JP2007237054A - Method of recycling multicomponent metal plating waste liquid sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recycling multicomponent metal plating waste liquid sludge capable of separately recovering valuables from the multicomponent metal plating waste liquid sludge at a low cost to recycle it. <P>SOLUTION: The method comprises the first process for dissolving the multicomponent metal plating waste liquid in an inorganic acid to recover a first treated liquid containing nickel, copper, zinc, iron, chromium and an organic substance, the second process for separating copper from the first treated liquid as a copper disposed iron powder to recover a second treated liquid containing nickel, zinc, iron, chromium and the organic substance, the third process for separating iron and chromium from the second treated liquid to recover a third treated liquid containing nickel and zinc, the fourth process for loading the third treated liquid with an iron powder to separate a nickel disposed iron powder to recover a fourth treated liquid containing zinc and iron, the fifth process for separating iron in the fourth treated liquid to recover a fifth treated liquid containing zinc, and the sixth process for separating zinc from the fifth treated liquid to provide the sixth treated liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a processing method for separating and recovering valuable materials from multicomponent plating waste liquid sludge for recycling. Here, multi-component plating waste sludge is a mixture of each plating waste sludge generated in the plating process when nickel plating, copper plating, zinc plating, and chromium plating are performed using iron as the material to be plated. In this case, the metal component contains nickel, copper, zinc, iron, and chromium.

For example, as a method of recovering the nickel content in the nickel plating waste liquid sludge, sulfuric acid is added to the nickel plating waste liquid sludge to dissolve the solid content to prepare a solution, and the nickel sulfate crystals are prepared from this solution by cooling crystallization. In order to further increase the nickel content recovery method by crystallization and recovery, nickel sulfate crystals are crystallized and recovered from the solution, and iron powder is added to the filtrate obtained by filtering the nickel sulfate crystals. There has been proposed a method in which a cooling crystallization process in which nickel ions remaining therein are deposited and recovered on the iron powder surface and a cementation process are combined (for example, see Patent Document 1).

Alternatively, calcium carbonate is added to a solution obtained by adding sulfuric acid to nickel plating waste sludge to dissolve the solid content, and divalent iron ions in the solution are changed to trivalent iron ions, and then the pH is adjusted to remove iron. Form a nickel stock solution, add calcium hydroxide to this nickel stock solution, adjust the pH, add acid to the nickel-containing gypsum produced and recovered, dissolve it as nickel hydroxide, extract the nickel content, add sulfuric acid to this A method of cooling and crystallizing the nickel sulfate solution produced in this way to crystallize and recover nickel sulfate crystals has been proposed (see, for example, Patent Document 2).

JP 2004-284848 A JP 2005-15272 A

Generally, in a plating processing factory, the amount of plating waste liquid sludge generated when a single type of metal plating processing is performed is small, and more than two types of metal plating processing steps are often performed. The plating waste liquid sludge generated in the plating process is mixed, and the plating waste liquid sludge containing a multi-component metal component is taken out from the plating processing factory and disposed at the final disposal site. On the other hand, when trying to efficiently recover (recycle) valuable metals from plating waste sludge, the generated plating waste sludge is stored in, for example, a storage tank, and the plating waste sludge has reached a certain amount. From the viewpoint of economy, it is desirable to collect valuable metals by batch processing at the time.

Accordingly, the plating waste liquid sludge to be treated is not limited to the plating waste liquid sludge generated by nickel plating. It is in the state of component plating waste liquid sludge. Here, it is very difficult to separate and collect nickel, copper, zinc, iron, and chromium from multi-component plating waste sludge by a dry method based on dry refining technology, and at such a high temperature that the metal melts. Since the processing is performed below, the energy consumed is enormous, which causes a problem economically. For this reason, it is necessary to use wet methods such as a coagulation precipitation method, a cementation method, an ion exchange resin method using a chelate resin, and a solvent extraction method. However, the ion exchange resin used in the ion exchange resin method and the extraction solvent used in the solvent extraction method are extremely expensive ones designed specifically for each. It is difficult to economically separate and collect copper, zinc, iron, and chromium. In addition, when the invention of Patent Document 1 using the cementation method and the invention of Patent Document 2 using the coagulation precipitation method are applied to multicomponent plating waste liquid sludge, the recovered iron and nickel are respectively copper and chromium. , And zinc will be mixed. For this reason, there exists a problem that the separate collection | recovery of each valuable metal cannot be performed accurately. And the problem that the purity of the nickel and iron collect | recovered falls and the utility value as a resource also arises arises.

The present invention has been made in view of such circumstances, and a recycling method for multi-component plating waste liquid sludge capable of separating and recovering valuable materials from multi-component plating waste liquid sludge at low cost and recycling them. The purpose is to provide.

The recycling method for multi-component plating waste liquid sludge according to the first aspect of the present invention is to add an inorganic acid to the multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, chromium, and organic matter. A sludge dissolution treatment is performed to dissolve the multi-component plating waste liquid sludge to form a dissolution treatment product, and the insoluble matter is removed from the dissolution treatment product so that a part of nickel, copper, zinc, iron, chromium, and organic matter is removed. A first step provided with an insoluble matter removal treatment for obtaining a mixed first treatment liquid;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step of forming a second treatment liquid containing zinc, iron, chromium, and organic matter;
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjuster to the second treatment solution to adjust the pH, and performing chromium neutralization treatment to change chromium ions in the second treatment solution to chromium hydroxide. And an oxidizing agent is added to the chromium hydroxide dispersion treatment solution to decompose organic substances present in the chromium hydroxide dispersion treatment solution and oxidize ferrous ions in the chromium hydroxide dispersion treatment solution. Then, ferric hydroxide starch is produced by performing a first iron neutralization treatment in which a ferric ion is added and then a pH adjusting agent is added to adjust the pH to convert the ferric ion to ferric hydroxide. A third step of separating the ferric hydroxide starch together with the chromium hydroxide into a third treatment liquid containing nickel and zinc;
The iron powder is added to the third treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the third treatment liquid are replaced with iron, and the nickel-attached iron powder on which nickel is deposited is separated, and zinc is separated. And a fourth step as a fourth treatment liquid containing iron,
An intermediate treatment solution is prepared by oxidizing the ferrous ions in the fourth treatment solution to ferric ions, and a pH adjuster is added to the intermediate treatment solution to adjust the pH. A second iron neutralization treatment for converting ferric ions to ferric hydroxide is performed to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. A fifth step as a treatment liquid;
Zinc neutralization treatment is performed by adjusting the pH of the fifth treatment liquid and changing zinc ions in the fifth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And a sixth step of making a sixth treatment liquid from which zinc has been removed,
Organic substances are decomposed from the multicomponent plating waste sludge to separate and recover nickel, copper, zinc, iron, and chromium.
Here, nickel, copper, zinc, iron, and chromium include these compounds in addition to nickel, copper, zinc, iron, and chromium metals. The organic substance includes an organic polymer-based flocculant and the like.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. It is good to do.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, in the intermediate treatment, an oxidizing agent is added to the fourth treatment liquid to maintain a redox potential at 600 mV or higher, All ferrous ions in the treatment liquid can be oxidized to ferric ions.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, in the intermediate treatment, an oxidizing agent is added to the fourth treatment liquid to maintain the oxidation-reduction potential at 400 mV or more and 500 mV or less. Iron neutralization to convert ferric ions to ferric hydroxide by oxidizing a part of ferrous ions in the fourth treatment liquid to ferric ions and adjusting the pH by adding a pH adjuster. As an iron neutralization treatment liquid in which ferric hydroxide is dispersed, an oxidizing agent is added to the iron neutralization treatment liquid so that the oxidation-reduction potential is maintained at 600 mV or more, and the ferrous iron in the iron neutralization treatment liquid All ions can be oxidized to ferric ions. Here, the oxidizing agent added to the iron neutralization treatment liquid is preferably hydrogen peroxide.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, ferrous iron can be added together with an oxidant to the chromium hydroxide dispersion treatment liquid, and the oxidant added to the fourth treatment liquid Is preferably hydrogen peroxide. The oxidizing agent added to the chromium hydroxide dispersion treatment liquid is preferably hydrogen peroxide. Further, the first iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, instead of the third step, a pH adjuster is added to the second treatment liquid to adjust the pH, and the second treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to decompose organic substances present in the chromium removal solution and to oxidize a part of the ferrous ions present in the chromium removal solution. Further, a 1A iron neutralization treatment is carried out by adding a pH adjuster to adjust the pH to ferric hydroxide to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed. Add oxidant to make redox potential 600m While maintaining the above, the organic substances present in the dispersion treatment liquid are decomposed and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions, and then a pH adjuster is added to the dispersion treatment liquid. In addition, a ferrous hydroxide starch is formed by adjusting the pH and changing to ferric hydroxide to form a ferric hydroxide starch, separating the ferric hydroxide starch into nickel, and The 3rd A process used as the 3rd processing liquid containing zinc can be performed. The 1B iron neutralization treatment is preferably performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multi-component plating waste liquid sludge according to the first invention, instead of the third step, a pH adjuster is added to the second treatment liquid to adjust the pH, and the second treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 600 mV or more to decompose organic substances present in the chromium removal solution, and ferrous ions in the chromium removal solution are oxidized to ferric ions, and then a pH adjuster is added. To adjust the pH to ferric hydroxide to neutralize the 1C iron to produce ferric hydroxide starch, and separate the ferric hydroxide starch into nickel and zinc 3B process is carried out with the third treatment liquid containing And it can also be. Here, the 1C iron neutralization treatment is preferably performed at 60 ° C. or more, preferably 75 ° C. or more, and less than 100 ° C., preferably 85 ° C. or less.

A recycling method for multicomponent plating waste liquid sludge according to the second invention in accordance with the above object comprises adding an inorganic acid to a multicomponent plating waste liquid sludge containing nickel, copper, zinc, iron, and chromium, and A sludge dissolution treatment is performed to dissolve the component-based plating waste liquid sludge to form a dissolution treatment product. The first treatment solution in which nickel, copper, zinc, iron, and chromium are mixed by removing the insoluble matter from the dissolution treatment product A first step provided with an insoluble matter removal process to obtain;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step as a second treatment liquid containing zinc, iron, and chromium;
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjuster to the second treatment solution to adjust the pH, and performing chromium neutralization treatment to change chromium ions in the second treatment solution to chromium hydroxide. And oxidize the chromium hydroxide dispersion treatment solution to oxidize ferrous ions in the chromium hydroxide dispersion treatment solution to ferric ions, and then adjust the pH by adding a pH adjuster. Then, ferric hydroxide starch is produced by performing a first iron neutralization treatment for converting ferric ions to ferric hydroxide, and separating the ferric hydroxide starch together with the chromium hydroxide. And a third step of making a third treatment liquid containing nickel and zinc,
The iron powder is added to the third treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the third treatment liquid are replaced with iron, and the nickel-attached iron powder on which nickel is deposited is separated, and zinc is separated. And a fourth step as a fourth treatment liquid containing iron,
An intermediate treatment solution is prepared by oxidizing the ferrous ions in the fourth treatment solution to ferric ions, and a pH adjuster is added to the intermediate treatment solution to adjust the pH. A second iron neutralization treatment for converting ferric ions to ferric hydroxide is performed to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. A fifth step as a treatment liquid;
Zinc neutralization treatment is performed by adjusting the pH of the fifth treatment liquid and changing zinc ions in the fifth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And a sixth step of making a sixth treatment liquid from which zinc has been removed,
Nickel, copper, zinc, iron and chromium are separated and recovered from the multi-component plating waste sludge.
Here, nickel, copper, zinc, iron, and chromium include these compounds in addition to nickel, copper, zinc, iron, and chromium metals.

In the recycling method for multi-component plating waste liquid sludge according to the second invention, the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. Good to do.

In the recycling method for multi-component plating waste liquid sludge according to the second invention, in the intermediate treatment, an oxidizing agent is added to the fourth treatment liquid to maintain an oxidation-reduction potential at 600 mV or more. All ferrous ions in the treatment liquid can be oxidized to ferric ions. Here, the oxidizing agent added to the fourth treatment liquid is preferably hydrogen peroxide.

In the recycling method for multi-component plating waste liquid sludge according to the second invention, the intermediate treatment is performed by adding an oxidizing agent to the fourth treatment liquid and maintaining the oxidation-reduction potential at 400 mV or more and 500 mV or less. Iron neutralization to convert ferric ions to ferric hydroxide by oxidizing a part of ferrous ions in the fourth treatment liquid to ferric ions and adjusting the pH by adding a pH adjuster. As an iron neutralization treatment liquid in which ferric hydroxide is dispersed, an oxidizing agent is added to the iron neutralization treatment liquid so that the oxidation-reduction potential is maintained at 600 mV or more, and the ferrous iron in the iron neutralization treatment liquid All ions can be oxidized to ferric ions. Here, the oxidizing agent added to the fourth treatment liquid and the iron neutralization treatment liquid is preferably hydrogen peroxide.

In the recycling method for multicomponent plating waste liquid sludge according to the second invention, it is preferable that the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide. Further, the first iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multi-component plating waste liquid sludge according to the second invention, instead of the third step, a pH adjuster is added to the second processing solution to adjust the pH, and the second processing solution A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to oxidize part of the ferrous ions present in the chromium removal solution to ferric ions, and further adjust the pH by adding a pH adjuster. 1A iron neutralization treatment to convert to ferric hydroxide is performed to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed, and an oxidizing agent is added to the dispersion treatment liquid to keep the oxidation-reduction potential at 600 mV or more. The residue of ferrous ions in the dispersion treatment liquid Is oxidized to ferric ions, and then a pH adjusting agent is added to the dispersion treatment solution to adjust the pH to ferric hydroxide to perform 1B iron neutralization treatment, thereby ferric hydroxide A 3A process which makes a starch and isolate | separates this ferric hydroxide starch and makes it the 3rd process liquid containing nickel and zinc can be performed. Here, the 1B iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multi-component plating waste liquid sludge according to the second invention, instead of the third step, a pH adjuster is added to the second processing solution to adjust the pH, and the second processing solution A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 600 mV or more to oxidize ferrous ions in the chromium removal solution to ferric ions, and then a pH adjuster is added to adjust the pH to ferric hydroxide. Step 3B, wherein the iron neutralization treatment of 1C to be changed is performed to produce ferric hydroxide starch, and the ferric hydroxide starch is separated to form a third treatment liquid containing nickel and zinc. It can also be done. Here, the iron neutralization treatment of 1C is preferably performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

The method for recycling multi-component plating waste liquid sludge according to the third aspect of the present invention is to add an inorganic acid to the multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, chromium, and organic matter. A sludge dissolution treatment is performed to dissolve the multi-component plating waste liquid sludge to form a dissolution treatment product, and the insoluble matter is removed from the dissolution treatment product so that a part of nickel, copper, zinc, iron, chromium, and organic matter is removed. A first step provided with an insoluble matter removal treatment for obtaining a mixed first treatment liquid;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step of forming a second treatment liquid containing zinc, iron, chromium, and organic matter;
The iron powder is added to the second treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the second treatment liquid are replaced with iron, and the nickel-adhered iron powder on which nickel is deposited is separated, and zinc is separated. , A third step as a third treatment liquid containing iron, chromium, and organic matter,
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjusting agent to the third treatment solution to adjust the pH, and performing a chromium neutralization treatment in which chromium ions in the third treatment solution are changed to chromium hydroxide. And an oxidizing agent is added to the chromium hydroxide dispersion treatment solution to decompose organic substances present in the chromium hydroxide dispersion treatment solution and oxidize ferrous ions in the chromium hydroxide dispersion treatment solution. Then, a ferric hydroxide starch is formed by carrying out an iron neutralization treatment by adjusting the pH by adding a pH adjusting agent to convert the ferric ion to ferric hydroxide. A fourth step of separating ferric oxide starch together with the chromium hydroxide to form a fourth treatment liquid containing zinc;
Zinc neutralization treatment is performed by adjusting the pH of the fourth treatment liquid and changing zinc ions in the fourth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And having a fifth step as a fifth treatment liquid from which zinc has been removed,
Organic substances are decomposed from the multicomponent plating waste sludge to separate and recover nickel, copper, zinc, iron, and chromium.
Here, nickel, copper, zinc, iron, and chromium include these compounds in addition to nickel, copper, zinc, iron, and chromium metals. The organic substance includes an organic polymer-based flocculant and the like.

In the recycling method for multi-component plating waste liquid sludge according to the third invention, the iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. Good. Furthermore, ferrous iron can be added together with an oxidizing agent to the chromium hydroxide dispersion treatment solution. The oxidizing agent added to the chromium hydroxide dispersion treatment liquid is preferably hydrogen peroxide.

In the recycling method for multi-component plating waste liquid sludge according to the third invention, instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to decompose organic substances present in the chromium removal solution and to oxidize a part of the ferrous ions present in the chromium removal solution. In addition, a first iron neutralization treatment is performed by adding a pH adjuster to adjust the pH to ferric hydroxide, thereby obtaining a dispersion treatment liquid in which ferric hydroxide is dispersed. Oxidizing agent added to reduce oxidation potential to 600 mV The organic substances present in the dispersion treatment liquid are decomposed while being held on the top, and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions, and then a pH adjuster is added to the dispersion treatment liquid. In addition, a second iron neutralization treatment is performed to adjust the pH to ferric hydroxide to produce ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc The 4A process which makes the 4th processing liquid to perform can be performed. Here, the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multi-component plating waste liquid sludge according to the third invention, instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 600 mV or more to decompose organic substances present in the chromium removal solution, and ferrous ions in the chromium removal solution are oxidized to ferric ions, and then a pH adjuster is added. A third iron neutralization treatment is performed to adjust the pH to ferric hydroxide to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. The 4B process which makes a 4th processing liquid can also be performed. Here, the third iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

A recycling method for multi-component plating waste liquid sludge according to the fourth aspect of the present invention in accordance with the above object comprises adding an inorganic acid to a multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, and chromium, and A sludge dissolution treatment is performed to dissolve the component-based plating waste liquid sludge to form a dissolution treatment product. The first treatment solution in which nickel, copper, zinc, iron, and chromium are mixed by removing insolubles from the dissolution treatment product A first step provided with an insoluble matter removal process to obtain;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step as a second treatment liquid containing zinc, iron, and chromium;
The iron powder is added to the second treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the second treatment liquid are replaced with iron, and the nickel-adhered iron powder on which nickel is deposited is separated, and zinc is separated. A third step as a third treatment liquid containing iron, chromium, and
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjusting agent to the third treatment solution to adjust the pH, and performing a chromium neutralization treatment in which chromium ions in the third treatment solution are changed to chromium hydroxide. And oxidize the chromium hydroxide dispersion treatment solution to oxidize ferrous ions in the chromium hydroxide dispersion treatment solution to ferric ions, and then adjust the pH by adding a pH adjuster. Then, ferric hydroxide starch is produced by performing iron neutralization treatment to convert ferric ions to ferric hydroxide, and the ferric hydroxide starch is separated together with the chromium hydroxide to form zinc. A fourth step as a fourth treatment liquid containing
Zinc neutralization treatment is performed by adjusting the pH of the fourth treatment liquid and changing zinc ions in the fourth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And having a fifth step as a fifth treatment liquid from which zinc has been removed,
Nickel, copper, zinc, iron and chromium are separated and recovered from the multi-component plating waste sludge.
Here, nickel, copper, zinc, iron, and chromium include these compounds in addition to nickel, copper, zinc, iron, and chromium metals.

In the recycling method for multi-component plating waste liquid sludge according to the fourth invention, the iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. Good. The oxidizing agent added to the chromium hydroxide dispersion treatment liquid is preferably hydrogen peroxide.

In the recycling method for multicomponent plating waste liquid sludge according to the fourth invention, instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to oxidize part of the ferrous ions present in the chromium removal solution to ferric ions, and further adjust the pH by adding a pH adjuster. The first iron neutralization process to convert to ferric hydroxide is performed to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed, and an oxidizing agent is added to the dispersion treatment liquid to maintain the oxidation-reduction potential at 600 mV or higher. The balance of ferrous ions in the dispersion treatment liquid Oxidized to ferric ions, and then a second iron neutralization treatment was performed by adding a pH adjuster to the dispersion treatment liquid to adjust the pH to ferric hydroxide, thereby converting to ferric hydroxide starch. The 4th A process which makes a product and can separate this ferric hydroxide starch and makes it the 4th processing liquid containing zinc can be performed. Here, the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multicomponent plating waste liquid sludge according to the fourth invention, instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid A chromium neutralization treatment is carried out by changing the chromium ions into chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 600 mV or more to oxidize ferrous ions in the chromium removal solution to ferric ions, and then a pH adjuster is added to adjust the pH to ferric hydroxide. Performing the fourth iron neutralization treatment to produce ferric hydroxide starch, and separating the ferric hydroxide starch into a fourth treatment solution containing zinc. You can also. Here, the third iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, and less than 100 ° C., preferably 85 ° C. or lower.

In the recycling method for multicomponent plating waste liquid sludge according to the first to fourth inventions, the pH adjuster is preferably a weak alkali agent.

In the recycling method of multi-component plating waste liquid sludge according to the first to fourth inventions, hydrochloric acid is used as the inorganic acid in the first step, and the sludge dissolution treatment has a pH of 0.5 or more. At a temperature of 80 ° C. or higher and lower than 100 ° C. In addition, between the sludge dissolution treatment and the insoluble matter removal treatment, sulfuric acid is added to the dissolution treatment product, and a calcium source is further added so that the pH is 1 or more and 2 or less, and the temperature is 80 ° C or more and less than 100 ° C. It is preferable to produce gypsum.

In the recycling method of multicomponent plating waste liquid sludge according to the first to fourth inventions, sulfuric acid is used as the inorganic acid in the first step, and the sludge dissolution treatment has a pH of 0.5. 2 or less at a temperature of 80 ° C. or more and less than 100 ° C. Between the sludge dissolution treatment and the insoluble matter removal treatment, a calcium source is added to the dissolution treatment product to adjust the pH to 1 or more and 2 or less. Further, it is possible to provide a sulfate radical removing treatment in which the temperature is set to 80 ° C. or higher and lower than 100 ° C. to remove sulfate radicals in the dissolved processed product as gypsum.

In the recycling method of the multi-component plating waste liquid sludge according to claims 1 to 44, each metal can be sequentially separated and recovered from the multi-component plating waste liquid sludge, and each recovered metal is effective as a resource. It becomes possible to use. Here, since the nickel is separately collected after the zinc is separated and collected, the quality of the recovered nickel and zinc can be improved.

In particular, in the recycling method for multicomponent plating waste liquid sludge according to claims 2, 9, 11, 13, 15, 21, 23, 25, 27, 31, 33, 35, 38, and 40, water The production rate of ferric oxide starch is increased, and the particles of ferric hydroxide starch can be coarsened, and the filterability can be improved.

In the recycling method for multi-component plating waste liquid sludge according to claim 3, since all ferrous ions in the fourth treatment liquid are oxidized, iron is efficiently recovered in the fourth step. be able to. Here, when the organic substance is present in the fourth treatment liquid, the organic substance is decomposed simultaneously with the oxidation of the ferrous ion in the fourth treatment liquid, so that the organic substance is mixed in the fifth treatment liquid. Can be prevented.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 4, ferric hydroxide nuclei are generated from a part of ferrous ions in the fourth processing liquid, and then the remaining first Since all iron ions are oxidized to make the ferric hydroxide nucleus and ferric ions coexist, iron neutralization is further performed, so the ferric hydroxide in which the ferric hydroxide produced is pre-existing It is possible to achieve coarsening of the particles of ferric hydroxide starch. As a result, the filterability of the ferric hydroxide starch is improved, and it becomes possible to efficiently separate the ferric hydroxide starch. Here, when an organic substance is present in the fourth treatment liquid, oxidation of ferrous ions and decomposition of the organic substance are performed at the same time, and it becomes possible to prevent the organic substance from being mixed into the fifth treatment liquid. .
In the recycling method of the multicomponent plating waste liquid sludge according to claim 5 and 6, since hydrogen peroxide is used, ferrous ions can be efficiently oxidized and in the fourth processing liquid. The hydroxyl radicals can be efficiently generated from hydrogen peroxide by the ferrous ions, and when the organic matter remains in the fourth treatment liquid, the organic matter can be efficiently decomposed. It is possible to prevent organic substances from being mixed into the treatment liquid.

In the recycling processing method for multi-component plating waste liquid sludge according to claim 7, since ferrous iron is added together with the oxidizing agent, decomposition of organic substances in the third processing liquid can be promoted.
In the recycling method of the multicomponent plating waste liquid sludge according to claim 8, since the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide, hydroxy radicals are efficiently generated from the hydrogen peroxide, Organic matter can be decomposed efficiently.

In the recycling processing method of the multi-component plating waste liquid sludge according to claim 10, chromium and iron can be separated and recovered, so that they can be effectively used as a chromium raw material and an iron raw material. Moreover, since the organic substance is decomposed by the oxidizing agent, the recovery rate of nickel in the fourth step can be improved. Further, since ferric hydroxide nuclei are generated by performing the 1A iron neutralization treatment, and then the 1B iron neutralization treatment is performed, the ferric hydroxide produced by the 1B iron neutralization treatment is performed. Can be precipitated around the nucleus of ferric hydroxide produced by the iron neutralization treatment of 1A, and the coarsening of the particles of ferric hydroxide starch is achieved to improve filterability Is possible.

In the recycling method for multi-component plating waste liquid sludge according to claim 12, chromium and iron can be separated and recovered, so that they can be effectively used as a chromium raw material and an iron raw material. Moreover, since the organic substance is decomposed by the oxidizing agent, the recovery rate of nickel in the fourth step can be improved. Furthermore, since all the ferrous ions in the chromium removal solution are oxidized, the third treatment solution can be efficiently recovered.

In the multi-component plating waste liquid sludge recycling treatment method according to claim 16, since all ferrous ions in the fourth treatment liquid are oxidized, the recovery of iron mixed in the fourth step is efficient. Can be done.
In the recycling method of the multicomponent plating waste liquid sludge according to claim 17, ferrous ions can be efficiently oxidized with hydrogen peroxide.

In the recycling method of the multi-component plating waste liquid sludge according to claim 18, ferric hydroxide nuclei are generated from a part of ferrous ions in the fourth processing liquid, and then the remaining first Since all iron ions are oxidized to make the ferric hydroxide nucleus and ferric ions coexist, iron neutralization is further performed, so the ferric hydroxide in which the ferric hydroxide produced is pre-existing It is possible to achieve coarsening of the particles of ferric hydroxide starch. As a result, the filterability of the ferric hydroxide starch is improved, and it becomes possible to efficiently separate the ferric hydroxide starch.
In the recycling method for multi-component plating waste liquid sludge according to claim 19, ferrous ions can be efficiently oxidized with hydrogen peroxide.
In the recycling method of the multicomponent plating waste liquid sludge according to claim 20, since the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide, ferrous ions in the chromium hydroxide dispersion treatment liquid are efficiently used. Can be oxidized to ferric ions.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 22, since chromium and iron can be separated and recovered, they can be effectively used as a chromium raw material and an iron raw material. In addition, since ferrous hydroxide nuclei are generated by performing the 1A iron neutralization treatment, and then the 1B iron neutralization treatment is performed, the ferric hydroxide produced by the 1B iron neutralization treatment is performed. Can be precipitated around the nucleus of ferric hydroxide produced by the iron neutralization treatment of 1A, and the coarsening of the particles of ferric hydroxide starch is achieved to improve filterability Is possible.

In the recycling method of the multicomponent plating waste liquid sludge according to the twenty-fourth aspect, chromium and iron can be separated and recovered, so that they can be effectively used as a chromium raw material and an iron raw material. In addition, since all ferrous ions in the chromium removal solution are oxidized, the third treatment solution can be efficiently recovered.

In the recycling method of the multicomponent plating waste liquid sludge according to the twenty-eighth aspect, ferrous iron is added together with the oxidizing agent, so that the decomposition of the organic matter can be promoted.
In the recycling treatment method for multi-component plating waste liquid sludge according to claim 29, since the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide, hydroxy radicals are efficiently generated from hydrogen peroxide, Organic matter can be decomposed efficiently.

In the recycling method of the multicomponent plating waste liquid sludge according to the thirty-third aspect, since chromium and iron can be separately collected, it can be effectively used as a chromium raw material and an iron raw material. Moreover, since the 2nd iron neutralization process is performed after performing the 1st iron neutralization process and producing | generating the nucleus of ferric hydroxide, the 2nd hydroxide produced | generated by the 2nd iron neutralization process Iron can be precipitated centering around the ferric hydroxide nucleus produced by the first iron neutralization treatment, and the coarsening of the ferric hydroxide starch particles is achieved, thereby improving the filterability. It becomes possible. Furthermore, since the organic substance is decomposed by the oxidizing agent, it is possible to prevent the organic substance from being mixed into the fourth treatment liquid.

In the recycling method of the multicomponent plating waste liquid sludge according to the thirty-second aspect, chromium and iron can be separated and recovered, so that they can be effectively used as a chromium raw material and an iron raw material. In addition, since all ferrous ions in the chromium removal solution are oxidized, the fourth treatment solution can be efficiently recovered. Furthermore, since the organic substance is decomposed by the oxidizing agent, it is possible to prevent the organic substance from being mixed into the fourth treatment liquid.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 36, since the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide, ferrous ions in the chromium hydroxide dispersion treatment liquid are efficiently used. Can be oxidized to ferric ions.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 37, since chromium and iron can be separated and recovered, they can be effectively used as a chromium raw material and an iron raw material. Moreover, since the 2nd iron neutralization process is performed after performing the 1st iron neutralization process and producing | generating the nucleus of ferric hydroxide, the 2nd hydroxide produced | generated by the 2nd iron neutralization process Iron can be precipitated centering around the ferric hydroxide nucleus produced by the first iron neutralization treatment, and the coarsening of the ferric hydroxide starch particles is achieved, thereby improving the filterability. It becomes possible.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 39, chromium and iron can be separated and recovered, so that they can be effectively used as a chromium raw material and an iron raw material. In addition, since all ferrous ions in the chromium removal solution are oxidized, the fourth treatment solution can be efficiently recovered.

In the recycling method for multi-component plating waste liquid sludge according to claim 41, since a weak alkaline agent is used as a pH adjuster, the generation of a local high pH region is suppressed during neutralization. Is possible. Thereby, it becomes possible to produce only a desired metal hydroxide, and it is possible to carry out fractional recovery of nickel, copper, zinc, iron, and chromium with high accuracy.

In the recycling method of the multi-component plating waste liquid sludge according to claim 42, each metal component is made to exist in a chloride state in the dissolved processed product by using hydrochloric acid, and each metal component is converted into a hydroxide. In this state, it is possible to easily recover, and it is possible to increase both the recovery accuracy and recovery rate of each metal component. Moreover, even if organic substance exists in multicomponent plating waste liquid sludge by making temperature into 80 to 100 degreeC, organic substance can be decomposed | disassembled.

In the recycling method of the multicomponent plating waste liquid sludge according to claim 43, gypsum is present in the insoluble matter, and the filtration resistance of the insoluble matter layer is lowered to move the liquid in the insoluble matter layer. This makes it possible to easily remove the insoluble matter. As a result, it becomes possible to efficiently separate insoluble components. Moreover, since the organic substance which was not decomposed | disassembled with hydrochloric acid adheres to the gypsum which produces | generates, an organic substance can also be isolate | separated efficiently.

In the recycling method for multi-component plating waste liquid sludge according to claim 44, a dissolved processed product can be obtained at low cost by using sulfuric acid. Further, by setting the temperature to 80 ° C. or more and less than 100 ° C., the organic matter can be decomposed even if the organic matter is present in the multicomponent plating waste liquid sludge. Moreover, since the organic substance which was not decomposed | disassembled with a sulfuric acid adheres to the gypsum which produces | generates, organic substance can also be isolate | separated efficiently. Then, by performing the sulfate radical removal treatment, gypsum is present in the insoluble content layer, the filtration resistance is lowered, and the liquid can be easily moved in the insoluble content layer, and the insoluble content is easily removed. It becomes possible. Furthermore, the content of sulfate radicals in the first treatment liquid can be reduced, and an inexpensive alkaline agent containing calcium such as slaked lime can be used, so that the treatment cost can be reduced.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 and FIG. 2 are partial process explanatory views of the method for recycling the multi-component plating waste liquid sludge according to the first embodiment of the present invention, and FIG. 3 shows the recycling of the multi-component plating waste liquid sludge. FIG. 4 and FIG. 5 are partial process explanatory views of a multi-component plating waste liquid sludge recycling process method according to the second embodiment of the present invention, and FIG. 6 is a partial process explanatory view according to a modified example of the recycling method of the multi-component plating waste liquid sludge, and FIGS. 7 and 8 show the re-treatment of the multi-component plating waste liquid sludge according to the third embodiment of the present invention. FIG. 9 is a partial process explanatory diagram according to a modified example of the multi-component plating waste liquid sludge recycling process method, and FIGS. 10 and 11 illustrate the fourth embodiment of the present invention. Partial process of recycling method of multi-component plating waste liquid sludge according to form FIG. 12 is an explanatory diagram of partial processes according to a modification of the recycling method for multi-component plating waste liquid sludge, and FIGS. 13 and 14 are multi-component plating according to the fifth embodiment of the present invention. FIG. 15 and FIG. 16 are partial process explanatory views of a multi-component plating waste liquid sludge recycling treatment method according to the sixth embodiment of the present invention. 17 is a partial process explanatory diagram according to a modification of the multi-component plating waste liquid sludge recycling method, and FIGS. 18 and 19 are drawings of the multi-component plating waste liquid sludge according to the seventh embodiment of the present invention. FIG. 20 and FIG. 21 are partial process explanatory views of a recycling process method for multi-component plating waste liquid sludge according to the eighth embodiment of the present invention, and FIG. Changes in recycling method of component plating waste liquid sludge It is a partial process diagram according to the embodiment.

As shown in FIGS. 1 and 2, the multi-component plating waste liquid sludge recycling method (hereinafter simply referred to as sludge recycling method) according to the first embodiment of the present invention is, for example, While adding organic acid and hydrochloric acid as an inorganic acid to multi-component plating waste sludge (hereinafter simply referred to as sludge) in which nickel, copper, zinc, iron, and chromium are all present in the state of hydroxide, the organic substance is decomposed. Insoluble content removal that obtains the first treatment liquid in which nickel, copper, zinc, iron, chromium, and a part of organic matters are mixed by performing sludge dissolution treatment to form a dissolution treatment product and removing insoluble matter from the dissolution treatment product The first step in which the treatment is provided, and hydrochloric acid, which is an example of iron powder and acid, are added to the first treatment liquid to adjust the oxidation-reduction potential and the pH, and the copper ions and iron in the first treatment liquid are replaced on the surface. Forms copper-adhered iron powder with deposited copper Copper recovery cementation) is, by separating the copper deposited iron powder has nickel, zinc, iron, chromium, and a second step of the second processing solution containing an organic material. Here, the organic substance refers to, for example, an organic polymer used as a flocculant when neutralizing a plating waste liquid discharged from a plating establishment and aggregating and precipitating it as a hydroxide.

In addition, the waste sludge recycling treatment method adds a weak alkaline agent such as calcium carbonate to the second treatment liquid as a pH adjuster to adjust the pH, and converts chromium ions in the second treatment liquid to chromium hydroxide. Change the chromium neutralization treatment to make a chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed, add hydrogen peroxide as an oxidizing agent to the chromium hydroxide dispersion treatment liquid, and remove the organic matter remaining in the chromium hydroxide dispersion treatment liquid. It decomposes and oxidizes ferrous ions in the chromium hydroxide dispersion treatment solution to ferric ions, and then adjusts the pH by adding a weak alkaline agent such as calcium carbonate as a pH adjuster to adjust the pH. A first ferrous hydroxide neutralization treatment is performed to convert the ions to ferric hydroxide to produce ferric hydroxide starch, and the ferric hydroxide starch is separated together with chromium hydroxide to contain nickel and zinc. First And a third step of the process liquid.

Furthermore, the waste sludge recycling treatment method adds iron powder and hydrochloric acid, which is an example of an acid, to the third treatment liquid to adjust the oxidation-reduction potential and pH to replace nickel ions and iron in the third treatment liquid. And forming a nickel-attached iron powder with nickel deposited on the surface (nickel recovery cementation), separating the nickel-attached iron powder into a fourth treatment liquid containing zinc and iron, and a fourth treatment liquid Intermediate treatment solution is prepared by oxidizing intermediate ferrous ions to ferric ions, and a weak alkaline agent such as calcium carbonate is added to the intermediate treatment solution to adjust the pH. Then, a second iron neutralization treatment is performed to convert ferric ions to ferric hydroxide to produce ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. The fifth step as the fifth treatment liquid and the fifth treatment liquid with alkali For example, pH is adjusted by adding slaked lime, zinc neutralization treatment is performed by changing zinc ions in the fifth treatment liquid to zinc hydroxide to produce zinc hydroxide starch, and zinc hydroxide starch is separated. And a sixth step as a sixth treatment liquid from which zinc has been removed. Hereinafter, these will be described in detail.

As shown in FIG. 1 and FIG. 2, in the first step, first, multi-component plating waste liquid sludge is received and mixed with stirring to prepare a slurry having a solid content concentration of about 10 wt%, for example. Next, hydrochloric acid is added to the slurry to adjust the pH to 0.5 or more and 2 or less, for example, about 1, and the mixture is stirred for 60 minutes or more. At this time, the temperature of the slurry is adjusted to 80 ° C. or more and less than 100 ° C. By the above operation, the solid content (hydroxide of each metal) in the slurry is dissolved as ions by the following reaction (hereinafter, sludge dissolution treatment).
Cr (OH) ₃ + 3H ⁺ + 3Cl ⁻ → Cr ³⁺ + 3Cl ⁻ + 3H ₂ O
Cu (OH) ₂ + 2H ⁺ + 2Cl ⁻ → Cu 2 ⁺ + 2Cl ⁻ + 2H ₂ O
Fe (OH) ₂ + 2H ⁺ + 2Cl ⁻ → Fe ²⁺ + 2Cl ⁻ + 2H ₂ O
Fe (OH) ₃ + 3H ⁺ + 3Cl ⁻ → Fe ³⁺ + 3Cl ⁻ + 3H ₂ O
Ni (OH) ₂ + 2H ⁺ + 2Cl ⁻ → Ni ²⁺ + 2Cl ⁻ + 2H ₂ O
Zn (OH) ₂ + 2H ⁺ + 2Cl ⁻ → Zn ²⁺ + 2Cl ⁻ + 2H ₂ O
Here, the pH is set to 0.5 to 2 because when the pH exceeds 2, the amount of undissolved sludge increases and the amount of recovered metal decreases, which is not preferable. This is because the amount of acid used is extremely increased and becomes uneconomical. Moreover, organic substance can be decomposed | disassembled by making temperature of a slurry into 80 degreeC or more and less than 100 degreeC, and stirring for 60 minutes or more.

Subsequently, the dissolved processed product is treated with, for example, a filter press which is an example of solid-liquid separation, and the insoluble matter is separated as a solid layer (hereinafter referred to as cake), and the first treatment liquid is recovered (insoluble matter removal). processing). Insoluble matter (insoluble residue) separated as a cake is disposed of as waste. Here, since the organic matter contained in the sludge is decomposed, clogging of the filter cloth can be suppressed when performing the filter press. Then, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion (the first step).

While adding iron powder to the recovered first treatment liquid, hydrochloric acid is added so that the pH is 3 or less, and the temperature of the first treatment liquid is maintained at 30 to 80 ° C., for example, 40 ° C. (ORP) is adjusted to −400 mV or more and stirred for a predetermined time (20 to 60 minutes, for example, 30 minutes) (copper recovery cementation). Thereby, the chemical reaction shown below progresses between the copper ions and iron in the first treatment liquid, copper-adhered iron powder in which copper is deposited on the surface of the iron powder is formed, and the copper ions in the solution are removed. . As iron powder, for example, atomized iron powder or converter dust refined iron powder can be used.
2Fe ³⁺ + Fe → 3Fe ²⁺
Cu ²⁺ + Fe → Cu ↓ + Fe ²⁺ (Copper recovery cementation)
Fe + 2H ⁺ + 2Cl ⁻ → Fe ²⁺ + 2Cl ⁻ + H ₂ ↑
Here, by setting the pH to 3 or less, it is possible to prevent the chromium ions in the first treatment liquid from being precipitated as chromium hydroxide starch during copper recovery cementation. Moreover, it can prevent that nickel ion and iron substitute and nickel precipitates on the iron powder surface by making ORP into -400mV or more. And after predetermined time progress, the 1st processing liquid in which copper adhesion iron powder is suspended is separated into solid and liquid, for example with a filter press, and copper adhesion iron powder is separated as a cake, and the 2nd processing liquid is collected (above). , The second step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion. The separated copper-attached iron powder can be used as a copper refining raw material, for example.

The temperature of the recovered second treatment liquid is kept at 30 to 80 ° C., for example 60 ° C., and a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 3 or more and 5 or less, for example, about 4.2. And stirring for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, the chemical reaction shown below proceeds between the chromium ions and calcium carbonate in the second treatment liquid, the chromium ions are changed to chromium hydroxide, and the chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed is obtained. It is formed.
Cr ³⁺ + 3Cl ⁻ + 3CaCO ₃ + 3H ₂ O
→ Cr (OH) ₃ ↓ + 3Cl ⁻ + 3Ca ²⁺ + 3HCO ₃ ^{− *}
Here, HCO ₃ ^{- *} may, HCO ₃ ^- is obtained by collectively underwater carbon dioxide produced by the decomposition of various carbon component and calcium carbonate are dissolved, such as. The reason why the pH is 3 to 5 is that when the pH is less than 3, the neutralization amount of chromium decreases, and when the pH exceeds 5, nickel hydroxide is generated together with chromium hydroxide. By using calcium carbonate, which is a weak alkali, it is possible to suppress the formation of a local high pH region and prevent the formation of nickel hydroxide when performing chromium neutralization.

Subsequently, the temperature of the chromium hydroxide dispersion treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the chromium hydroxide dispersion treatment liquid to 600 mV or more for a predetermined time (20 Stir for ~ 60 minutes, eg 25 minutes. As a result, the chemical reaction shown below proceeds, and all the ferrous ions in the chromium hydroxide dispersion treatment liquid are oxidized to change to ferric ions, and remain in the chromium hydroxide dispersion treatment liquid. Organic substances are also oxidized and decomposed.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance. Further, when a large amount of organic substance is present in the chromium hydroxide dispersion treatment liquid, ferrous iron is added. Thereby, a large amount of hydroxy radicals are generated, and the decomposition of the organic matter is promoted.

Then, the temperature of the chromium hydroxide dispersion treatment liquid is maintained at 60 ° C. or more and less than 100 ° C., for example, 80 ° C., and a weak alkali agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less. Adjust to about 3.5 and stir for a predetermined time (20 to 60 minutes, for example, 30 minutes) (first iron neutralization). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the chromium hydroxide dispersion treatment liquid, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Moreover, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only part of the ferric iron became ferric hydroxide, and when the pH exceeded 5, This is because zinc oxide is generated. By setting the temperature to 60 ° C. or higher and lower than 100 ° C., preferably 75 ° C. or higher and 85 ° C. or lower, the production rate of ferric hydroxide can be increased. By agglomerating chromium hydroxide present in the dispersion treatment liquid as a nucleus, particles of ferric hydroxide starch can be coarsened. For this reason, after a predetermined time has passed, the filterability when a liquid containing ferric hydroxide starch is solid-liquid separated by, for example, a filter press is improved, and the ferric hydroxide starch is converted to chromium hydroxide. It is separated as a cake together with the starch, and the third treatment liquid can be easily recovered (the third step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

While adding iron powder to the recovered third treatment liquid, hydrochloric acid is added so that the pH is 5 or less, and the temperature of the third treatment liquid is kept at 30 to 80 ° C., for example, 60 ° C., and the ORP of the third treatment liquid. Is adjusted to −400 mV or less, for example, −500 mV, and stirred for a predetermined time (180 to 300 minutes, for example, 240 minutes) (nickel recovery cementation). As a result, the chemical reaction shown below proceeds between the nickel ions and iron in the third treatment liquid to form nickel-attached iron powder in which nickel is deposited on the iron powder surface, and the nickel ions in the third treatment liquid are removed. Is done. As iron powder, for example, atomized iron powder or converter dust refined iron powder can be used.
2Fe ³⁺ + Fe → 3Fe ²⁺
Ni ²⁺ + Fe → Ni ↓ + Fe ²⁺ (nickel recovery cementation)
Fe + 2H ⁺ + 2Cl ⁻ → Fe ²⁺ + 2Cl ⁻ + H ₂ ↑
In addition, since organic substance is decomposed | disassembled in the 1st and 3rd process and the content of organic substance is reduced, nickel recovery cementation can be performed efficiently.

By adjusting the pH to 5 or less, it is possible to prevent zinc ions in the third treatment liquid from being precipitated as zinc hydroxide starch during nickel recovery cementation. Moreover, when ORP exceeds -400 mV, substitution of nickel ion and iron is not performed, which is not preferable. The temperature of 30 to 80 ° C. is not preferable when the temperature is lower than 30 ° C., and the rate of progress of nickel recovery cementation is slow, and when the temperature exceeds 80 ° C., iron dissolution becomes remarkable and iron consumption increases. Then, after a predetermined time has elapsed, the third treatment liquid in which the nickel-adhered iron powder is suspended is solid-liquid separated by, for example, a filter press to separate the nickel-attached iron powder as a cake, and the fourth treatment liquid is recovered (above). , The fourth step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion. The separated nickel-adhered iron powder can be used as, for example, a stainless steel refining raw material.

Subsequently, the temperature of the recovered fourth treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., hydrogen peroxide is added as an oxidizing agent, and the ORP of the fourth treatment liquid is adjusted to 600 mV or more for a predetermined time (20 to 60). Stir for minutes, eg 25 minutes. Thereby, all the ferrous ions in the fourth treatment liquid are oxidized and changed to ferric ions. Even if organic matter remains in the fourth treatment liquid, the organic matter is simultaneously oxidized and decomposed when ferrous ions are oxidized to ferric ions. Next, the temperature of the fourth treatment liquid is maintained at 60 ° C. or higher and lower than 100 ° C., for example, 80 ° C., and a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or higher and 5 or lower, for example, 3. Adjust to about 5 and stir for a predetermined time (30 to 90 minutes, for example, 60 minutes) (second iron neutralization). As a result, a chemical reaction proceeds between the ferric ions and calcium carbonate in the fourth treatment liquid, and an intermediate treatment liquid in which the ferric ions are changed to ferric hydroxide is prepared.

Here, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only a part of the ferric ion became ferric hydroxide, and when the pH exceeded 5, ferric hydroxide. This is because zinc hydroxide is produced. By setting the temperature to 60 ° C. or more and less than 100 ° C., preferably 75 ° C. or more and 85 ° C. or less, the production rate of ferric hydroxide can be increased, and the resulting ferric hydroxide starch particles are coarse. Can be For this reason, the filterability at the time of solid-liquid separation of the liquid containing ferric hydroxide starch after, for example, a filter press can be improved. And the fifth treatment liquid can be easily recovered (the fifth step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion. The separated ferric hydroxide is dissolved in hydrochloric acid and used as ferric chloride.

The temperature of the recovered fifth treatment liquid is kept at 20 to 80 ° C., preferably 60 ° C. or more and 80 ° C. or less, and slaked lime is added as an alkaline agent to adjust the pH to 9 or more and 11 or less, for example, about 9.5, and predetermined Stir for time (15-60 minutes, eg 30 minutes) (zinc neutralization). Thereby, the chemical reaction shown below progresses between the zinc ions and the slaked lime in the fifth treatment liquid, and the zinc ions change to zinc hydroxide.
Zn ²⁺ + 2Cl ⁻ + Ca (OH) ₂ → Zn (OH) ₂ ↓ + Ca ²⁺ + 2Cl ⁻
Here, the reason why the pH is set to 9 to 11 is that when the pH is less than 9, only a part of zinc becomes zinc hydroxide, and when the pH exceeds 11, the zinc hydroxide is redissolved. Moreover, the production | generation rate of zinc hydroxide can be enlarged by making temperature into 60 to 80 degreeC, and the particle | grains of the zinc hydroxide starch to produce | generate can be coarsened. For this reason, after a predetermined time, the filterability when the liquid containing zinc hydroxide starch is solid-liquid separated by, for example, a filter press can be improved, and the zinc hydroxide starch can be easily recovered as a cake. Thus, the sixth processing liquid can be easily separated (sixth step). The separated cake is washed with washing water to reduce the residual liquid adhering to the cake side. Thereby, the amount of impurities contained in zinc hydroxide can be reduced.
Then, the separated sixth treatment liquid (process wastewater) is supplied to the water treatment facility and treated so that the chemical oxygen demand (COD), pH, etc. are below the emission standard value. Drain.

As shown in FIG. 3, in the modified example of the multi-component plating waste liquid sludge recycling method (hereinafter simply referred to as the waste sludge recycling process method) according to the first embodiment of the present invention, In 5 steps of intermediate treatment, hydrogen peroxide is added to the fourth treatment liquid as an oxidant to keep the oxidation-reduction potential at 400 mV or more and 500 mV or less to oxidize a part of ferrous ions in the fourth treatment liquid. Iron neutralization in which ferric hydroxide is dispersed by converting the ferric ion to ferric hydroxide by adjusting the pH by adding a weak alkali as a pH adjuster. As a treatment liquid, an intermediate treatment is performed by adding an oxidizing agent to the iron neutralization treatment liquid and maintaining the oxidation-reduction potential at 600 mV or more to oxidize all ferrous ions in the iron neutralization treatment liquid to ferric ions. A is performed to prepare an intermediate processing solution. Hereinafter, the intermediate process A will be described in detail.

The temperature of the fourth treatment liquid is kept at 20 to 80 ° C., for example 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the fourth treatment liquid to about 400 to 500 mV, for example about 450 mV, for a predetermined time (3 to 3 Stir for 10 minutes, eg 6 minutes. As a result, the chemical reaction shown below proceeds, and part of the ferrous ions in the fourth treatment liquid is oxidized to become ferric ions.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

Then, the temperature of the fourth treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., and calcium carbonate is added as a weak alkaline agent to adjust the pH to 2.5 or more and 5 or less, for example, about 3.5. Stir for time (3-10 minutes, eg 6 minutes). As a result, the chemical reaction shown below proceeds between the ferric ion and calcium carbonate in the fourth treatment liquid, and the ferric ion is changed to ferric hydroxide. It becomes an iron neutralization treatment liquid in which nuclei are dispersed (seeds of ferric hydroxide are generated) (iron neutralization (seeds generation)).
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Next, the temperature of the iron neutralization treatment solution is kept at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the iron neutralization treatment solution to 600 mV or more for a predetermined time (20 to 60). Stir for minutes, eg 25 minutes. As a result, an intermediate treatment liquid is formed in which all of the ferrous ions in the iron neutralization treatment liquid are oxidized and changed to ferric ions. In addition, even if organic matter remains in the fourth treatment liquid, the organic matter is oxidized and decomposed simultaneously when ferrous ions are oxidized to ferric ions, and the organic matter remains in the intermediate treatment liquid. Can be prevented.

As shown in FIGS. 4 and 5, the waste liquid sludge recycling process method according to the second embodiment of the present invention is the first of the waste liquid sludge recycling process method according to the first embodiment. The process is characterized in that a gypsum generation process for generating gypsum is provided between the sludge dissolution process and the insoluble matter removal process. In addition, the waste sludge recycling treatment method according to the second embodiment of the present invention uses the second treatment instead of the third step of the waste liquid sludge recycling treatment method according to the first embodiment. A weak alkaline agent is added to the solution as a pH adjuster to adjust the pH, a chromium neutralization treatment is performed by changing chromium ions in the second treatment solution to chromium hydroxide, and a chromium hydroxide starch is produced. The starch is separated into a chromium removal solution, an oxidant is added to the chromium removal solution, and ORP is maintained at 400 mV to 500 mV to decompose a part of organic substances present in the chromium removal solution and in the chromium removal solution. A part of the ferrous ions present in the iron is oxidized to ferric ions, and a weak alkaline agent is added to adjust the pH to ferric hydroxide to perform the iron neutralization treatment of 1A, Dispersion treatment liquid in which ferric hydroxide is dispersed Then, an oxidizing agent is added to the dispersion treatment liquid to maintain ORP at 600 mV or more to decompose the remaining organic matter remaining in the dispersion treatment liquid and oxidize the remaining ferrous ions in the dispersion treatment liquid to ferric iron. Then, a weak alkaline agent is added to the dispersion treatment solution to adjust the pH to ferric hydroxide, which is converted to ferric hydroxide to produce ferric hydroxide starch. It is characterized by performing the 3A process of separating ferric starch to form a third treatment liquid containing nickel and zinc, and other processes are recycling waste sludge according to the first embodiment. It is substantially the same as the processing method. For this reason, only a gypsum production | generation process and 3rd A process are demonstrated.

In the gypsum generation process, sulfuric acid is added to the dissolved product obtained by the sludge dissolution process, and then calcium carbonate, which is an example of a calcium source, is added to adjust the pH to 1 or more and 2 or less, for example, about 1.5. And stirring for a predetermined time (15 to 60 minutes, for example, 30 minutes). At this time, the temperature of the slurry is adjusted to 80 ° C. or more and less than 100 ° C. In the dissolved processed product, calcium carbonate and sulfuric acid react to form gypsum. At this time, organic substances present in the dissolved processed product are taken up by the gypsum and aggregate. For this reason, when performing the insoluble matter removal process by the filter press which is an example of solid-liquid separation, the filter cloth is prevented from being clogged with organic substances. Furthermore, since the gypsum produced | generated by the insoluble content removal process transfers to the cake side, the water permeability of a cake becomes large and the collection rate of a 1st process liquid becomes large. Here, the amount of gypsum produced in the gypsum production treatment is preferably limited to the amount necessary to improve the water permeability of the cake, and the weight of sulfuric acid added is, for example, 0.5 g per 100 g of dried sludge. ~ 5g. As a result, the amount of cake generated (the total amount of insoluble matter and gypsum) can be reduced by reducing the amount of gypsum produced, and the burden of waste treatment can be reduced.

In the 3A step, first, the temperature of the second treatment liquid is maintained at 30 to 80 ° C., for example, 60 ° C., and calcium carbonate is added as a weak alkaline agent to adjust the pH to 3 or more and 5 or less, for example, about 4.2. And stirring for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, a chemical reaction proceeds between the chromium ions and calcium carbonate in the second treatment liquid, and the chromium ions are changed to chromium hydroxide to form a liquid containing chromium hydroxide starch. And after predetermined time progress, the liquid containing a chromium hydroxide starch is solid-liquid separated, for example with a filter press, chromium hydroxide starch is isolate | separated as a cake, and chromium removal liquid is collect | recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

Next, the temperature of the chromium removal liquid from which the chromium hydroxide starch is separated is maintained at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent, so that the ORP of the chromium removal liquid is about 400 to 500 mV, for example, about 450 mV. And stirring for a predetermined time (3 to 10 minutes, for example, 6 minutes). As a result, the chemical reaction shown below proceeds, a part of the organic matter present in the chromium removal solution is decomposed, and a part of the ferrous ions present in the chromium removal solution is oxidized to ferric ions. become.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

And the temperature of chromium removal liquid is maintained at 20-80 degreeC, for example, 60 degreeC, calcium carbonate is added as a weak alkaline agent, pH is adjusted to 2.5 or more and 5 or less, for example, about 3.5, and predetermined time. Stir (3 to 10 minutes, for example, 6 minutes) (1A iron neutralization treatment). As a result, the chemical reaction shown below proceeds between the ferric ion and calcium carbonate in the chromium removal solution, and the ferric ion is changed to ferric hydroxide. Becomes a dispersion treatment liquid in which ferrous hydroxide seeds are produced.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Subsequently, the temperature of the dispersion treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the dispersion treatment liquid to 600 mV or more for a predetermined time (20 to 60 minutes, for example, 25 Stir for minutes). As a result, the chemical reaction shown below proceeds, and all the ferrous ions in the dispersion treatment liquid are oxidized to change to ferric ions, and the organic matter remaining in the dispersion treatment liquid is also oxidized and decomposed. To do.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

Then, the temperature of the dispersion treatment liquid is kept at 60 ° C. or less and less than 100 ° C., for example, 80 ° C., and a weak alkali agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less, for example, 3.5 It adjusts to a grade and it stirs for a predetermined time (20-60 minutes, for example, 30 minutes) (1B iron neutralization process). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the dispersion treatment liquid, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, HCO ₃ ^{- *} may, HCO ₃ ^- is obtained by collectively underwater carbon dioxide produced by the decomposition of various carbon component and calcium carbonate are dissolved, such as.

Moreover, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only a part of the ferric ion became ferric hydroxide, and when the pH exceeded 5, the ferric hydroxide was used. This is because zinc hydroxide is generated. By setting the temperature to 60 ° C. or more and less than 100 ° C., preferably 75 ° C. or more and 85 ° C. or less, the production rate of ferric hydroxide can be increased, and the produced ferric hydroxide is contained in the dispersion treatment liquid. By agglomerating the existing ferric hydroxide as a nucleus, the particles of ferric hydroxide starch can be coarsened. For this reason, after a predetermined time has passed, the filterability when the liquid containing ferric hydroxide starch is solid-liquid separated by, for example, a filter press is improved, and the ferric hydroxide starch is separated as a cake. The third treatment liquid can be easily recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

As shown in FIG. 6, in the modified example of the waste sludge recycling treatment method according to the second embodiment of the present invention, a weak alkaline agent is used as a pH adjuster in the second treatment liquid instead of the 3A step. Is added to adjust the pH, and the chromium ion in the second treatment liquid is changed to chromium hydroxide to carry out chromium neutralization to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to remove the chromium hydroxide. An oxidant is added to the chromium removal solution to maintain ORP at 600 mV or more to decompose organic substances remaining in the chromium removal solution and oxidize ferrous ions in the chromium removal solution to ferric ions, Then, a weak alkaline agent is added as a pH adjuster to adjust the pH to ferric hydroxide to perform 1C iron neutralization treatment to produce ferric hydroxide starch, and ferric hydroxide starch The product is separated and contains nickel and zinc. And performing the 3B step of the processing solution. Hereinafter, the 3B process will be described.

In the 3B step, first, the temperature of the second treatment liquid is maintained at 30 to 80 ° C., for example, 60 ° C., and a weak alkaline agent, for example, calcium carbonate is added to adjust the pH to 3 or more and 5 or less, for example, about 4.2. Adjust and stir for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, the chromium ion is changed to chromium hydroxide, and a liquid containing chromium hydroxide starch is formed. And after predetermined time progress, the liquid containing a chromium hydroxide starch is solid-liquid separated, for example with a filter press, chromium hydroxide starch is isolate | separated as a cake, and chromium removal liquid is collect | recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away.

Next, the temperature of the chromium removal liquid from which the chromium hydroxide starch has been separated is maintained at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the chromium removal liquid to 600 mV or more to obtain a predetermined value. Stir for time (20-60 minutes, eg 25 minutes). As a result, the chemical reaction shown below proceeds and all the ferrous ions in the chromium removal solution are oxidized to ferric ions, and organic substances present in the chromium removal solution are also oxidized and decomposed. To do.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

Then, the temperature of the chromium removal solution is kept at 60 ° C. or less and less than 100 ° C., for example, 80 ° C., and a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less, for example, 3.5 It adjusts to a grade and it stirs for a predetermined time (20 to 60 minutes, for example, 30 minutes) (1C iron neutralization process). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the chromium removal solution, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, HCO ₃ ^{- *} may, HCO ₃ ^- is obtained by collectively underwater carbon dioxide produced by the decomposition of various carbon component and calcium carbonate are dissolved, such as.

Moreover, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only a part of the ferric ion became ferric hydroxide, and when the pH exceeded 5, the ferric hydroxide was used. This is because zinc hydroxide is generated. By setting the temperature to 60 ° C. or more and less than 100 ° C., preferably 75 ° C. or more and 85 ° C. or less, the production rate of ferric hydroxide can be increased, and the particles of ferric hydroxide starch are coarsened. be able to.

The waste sludge recycling treatment method according to the third embodiment of the present invention shown in FIG. 7 and FIG. 8 is applied to the multicomponent plating waste liquid sludge containing nickel, copper, zinc, iron, and chromium as an inorganic acid. Sludge dissolution treatment is performed to dissolve the multi-component plating waste liquid sludge by adding hydrochloric acid to form a dissolution treatment product. The insoluble matter is removed from the dissolution treatment product and nickel, copper, zinc, iron, and chromium are mixed. 1st process which provided the insoluble matter removal process which obtains 1 process liquid, while adding iron powder to 1st process liquid, adjusting oxidation-reduction potential and pH, substituting the copper ion and iron in the 1st process liquid, and the surface The second step of separating the copper-deposited iron powder on which copper has been deposited to form a second treatment liquid containing nickel, zinc, iron, and chromium, and adjusting the pH by adding a pH adjuster to the second treatment liquid And the chromium ions in the second treatment liquid are converted to chromium hydroxide. Chromium neutralization treatment is performed to obtain a chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed, and an oxidizing agent is added to the chromium hydroxide dispersion treatment liquid to oxidize ferrous ions in the chromium hydroxide dispersion treatment liquid. Ferric hydroxide starch is then formed by adding a pH adjuster to adjust the pH and converting the ferric ion to ferric hydroxide to neutralize the iron. A third step of separating ferric hydroxide starch together with chromium hydroxide to form a third treatment solution containing nickel and zinc; adding iron powder to the third treatment solution; A fourth step of replacing the nickel ions and iron in the third treatment liquid and separating the nickel-attached iron powder on which nickel is deposited on the surface to obtain a fourth treatment liquid containing zinc and iron; 4 Oxidize ferrous ions in the processing solution to ferric ions An intermediate treatment solution is prepared by preparing an intermediate treatment solution, a pH adjuster is added to the intermediate treatment solution to adjust the pH, and a second iron neutralization treatment is performed to convert ferric ions to ferric hydroxide. 5th process which produces | generates ferric oxide starch, isolate | separates ferric hydroxide starch, and makes it the 5th process liquid containing zinc, adjusts the pH of a 5th process liquid, 5th process liquid A zinc neutralization treatment in which zinc ions are changed to zinc hydroxide to produce a zinc hydroxide starch, and a sixth treatment solution is obtained by separating the zinc hydroxide starch and removing zinc. It is characterized by the separate recovery of nickel, copper, zinc, iron, and chromium from multicomponent plating waste liquid sludge. Here, the organic substance contained in the sludge described in the first embodiment is decomposed simultaneously when the sludge is dissolved in an inorganic acid and when ferrous ions are oxidized to ferric ions. Therefore, the waste sludge recycling process method of the third embodiment is substantially the same except for the waste sludge recycling process example and the organic matter decomposition process according to the first embodiment. Can be the same.

Further, a modified example of the waste sludge recycling treatment method of the third embodiment shown in FIG. 9 is an intermediate treatment of the fifth step, in which hydrogen peroxide is added to the fourth treatment solution as an oxidant to reduce oxidation. The potential is kept at 400 mV or more and 500 mV or less by oxidizing part of ferrous ions in the fourth treatment liquid to ferric ions, and adding a weak alkali as a pH adjuster to adjust pH. As an iron neutralization treatment liquid in which ferric hydroxide is dispersed by performing iron neutralization to convert ferric hydroxide to ferric hydroxide, an oxidizing agent is added to the iron neutralization treatment liquid to maintain the redox potential at 600 mV or higher. Then, an intermediate treatment liquid is prepared by performing an intermediate treatment A that oxidizes all ferrous ions in the iron neutralization treatment liquid to ferric ions, and relates to the first embodiment. It should be substantially the same as the modification of the waste sludge recycling process. Kill. For this reason, the description about the waste liquid sludge recycling processing method of the third embodiment and its modification are omitted.

Further, the waste sludge recycling process method according to the fourth embodiment of the present invention shown in FIGS. 10 and 11 is the third step of the waste sludge recycling process method according to the third embodiment. Instead of adding a weak alkaline agent as a pH adjuster to the second treatment liquid, the pH is adjusted, and a chromium neutralization treatment is performed by changing chromium ions in the second treatment liquid to chromium hydroxide. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution to maintain the ORP at 400 mV or more and 500 mV or less to remove ferrous ions present in the chromium removal solution. Part 1 was oxidized to ferric ion, further weak alkaline agent was added to adjust pH to ferric hydroxide 1A iron neutralization treatment, ferric hydroxide was dispersed Add the oxidizing agent to the dispersion treatment liquid. RP is maintained at 600 mV or more, and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions. Then, a weak alkaline agent is added to the dispersion treatment liquid to adjust the pH, thereby adding a second hydroxide. Step 3A, wherein the iron neutralization treatment of 1B to be converted to iron is performed to produce ferric hydroxide starch, and the ferric hydroxide starch is separated to form a third treatment liquid containing nickel and zinc. The waste sludge recycling process method according to the fourth embodiment is a waste sludge recycling process example according to the second embodiment and the gypsum generation process of the first step. Can be substantially the same except for.

Further, in the modified example of the waste sludge recycling method of the fourth embodiment shown in FIG. 12, instead of the 3A step, a weak alkaline agent is added to the second treatment liquid as a pH adjuster to adjust the pH. The chromium ion in the second treatment liquid is changed to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated into a chromium removal liquid. Add an oxidizing agent to keep ORP at 600 mV or more to oxidize ferrous ions in the chromium removal solution to ferric ions, and then adjust the pH by adding a weak alkaline agent as a pH adjusting agent. Performing a 1C iron neutralization treatment to convert to ferric hydroxide to produce ferric hydroxide starch, separating the ferric hydroxide starch, and a third treatment liquid containing nickel and zinc; It is a feature that the 3B process is performed, and the second implementation It can be modified example substantially identical to the recycling processing method of the waste sludge according to state. For this reason, the description about the waste liquid sludge recycling processing method of the fourth embodiment and its modification are omitted.

As shown in FIGS. 13 and 14, the sludge recycling method according to the fifth embodiment of the present invention is such that, for example, organic matter and nickel, copper, zinc, iron, and chromium are all hydroxylated. Sludge dissolution treatment that decomposes organic matter by adding hydrochloric acid as an inorganic acid to multi-component plating waste sludge (hereinafter simply referred to as sludge) that exists in the state of the product to form a solution treatment product, and insoluble matter from the solution treatment product A first step of providing an insoluble matter removal treatment to obtain a first treatment liquid in which nickel, copper, zinc, iron, chromium, and a part of organic matter are mixed, and iron powder and acid in the first treatment liquid Hydrochloric acid is added as an example to adjust the oxidation-reduction potential and pH, replace copper ions and iron in the first treatment liquid, and form copper-attached iron powder with copper deposited on the surface (copper recovery cementation), Separation of copper adhering iron powder and nickel Zinc has iron, chromium, and a second step of the second treatment liquid containing organic matter. Here, the organic substance refers to, for example, an organic polymer used as a flocculant when neutralizing a plating waste liquid discharged from a plating establishment and aggregating and precipitating it as a hydroxide.

In addition, the waste sludge recycling treatment method according to the fifth embodiment adjusts the oxidation-reduction potential and pH by adding hydrochloric acid, which is an example of iron powder and acid, to the second treatment liquid, thereby adjusting the second treatment liquid. A nickel adhering iron powder in which nickel ions and iron are substituted and nickel is deposited on the surface is formed (nickel recovery cementation), and the nickel adhering iron powder is separated to contain zinc, iron, chromium, and organic matter. In the third step of making the treatment liquid, and adding a weak alkaline agent, for example, calcium carbonate, to the third treatment liquid as a pH adjuster to adjust the pH and changing the chromium ions in the third treatment liquid to chromium hydroxide A chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed by performing a summing treatment, and hydrogen peroxide as an oxidizing agent is added to the chromium hydroxide dispersion treatment liquid to decompose organic substances present in the chromium hydroxide dispersion treatment liquid. Both ferrous ions in the chromium hydroxide dispersion treatment are oxidized to ferric ions, and then a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH. Ferric hydroxide starch is produced by performing iron neutralization treatment to change to ferric hydroxide, and ferric hydroxide starch is separated together with chromium hydroxide to form a fourth treatment liquid containing zinc. And a fourth step.

Furthermore, the waste sludge recycling treatment method according to the fifth embodiment adjusts the pH by adding, for example, slaked lime as an alkaline agent to the fourth treatment liquid, and hydroxylates zinc ions in the fourth treatment liquid. A zinc neutralization treatment for changing to zinc to produce a zinc hydroxide starch, and a fifth step of separating the zinc hydroxide starch and removing the zinc to form a fifth treatment solution. Here, the first and second steps can be substantially the same as the first and second steps in the waste liquid sludge recycling treatment method of the first embodiment, respectively. For this reason, the 3rd-5th process in the recycling processing method of the waste liquid sludge concerning a 5th embodiment is explained.

While adding iron powder to the recovered second treatment liquid, hydrochloric acid is added so that the pH is 3 or less, and the temperature of the second treatment liquid is kept at 30 to 80 ° C., for example, 60 ° C., and the ORP of the second treatment liquid. Is adjusted to −400 mV or less, for example, −500 mV, and stirred for a predetermined time (180 to 300 minutes, for example, 240 minutes) (nickel recovery cementation). As a result, the chemical reaction shown below proceeds between nickel ions and iron in the second treatment liquid to form nickel-attached iron powder in which nickel is deposited on the iron powder surface, and the nickel ions in the second treatment liquid are removed. Is done. As iron powder, for example, atomized iron powder or converter dust refined iron powder can be used.
2Fe ³⁺ + Fe → 3Fe ²⁺
Ni ²⁺ + Fe → Ni ↓ + Fe ²⁺ (nickel recovery cementation)
Fe + 2H ⁺ + 2Cl ⁻ → Fe ²⁺ + 2Cl ⁻ + H ₂ ↑
In addition, since organic substance is decomposed | disassembled in the 1st process and content of organic substance is reduced, nickel recovery cementation can be performed efficiently.

By setting the pH to 3 or less, it is possible to prevent the chromium ions in the second treatment liquid from being precipitated as chromium hydroxide starch during nickel recovery cementation. Moreover, when ORP exceeds -400 mV, substitution of nickel ion and iron is not performed, which is not preferable. The temperature of 30 to 80 ° C. is not preferable when the temperature is lower than 30 ° C., and the rate of progress of nickel recovery cementation is slow, and when the temperature exceeds 80 ° C., iron dissolution becomes remarkable and iron consumption increases. Then, after a predetermined time has elapsed, the second treatment liquid in which the nickel-adhered iron powder is suspended is solid-liquid separated by, for example, a filter press to separate the nickel-attached iron powder as a cake, and the third treatment liquid is recovered (above). , Third step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion. The separated nickel-adhered iron powder can be used as, for example, a stainless steel refining raw material.

The temperature of the recovered third treatment liquid is kept at 30 to 80 ° C., for example, 60 ° C., and a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 3 or more and 5 or less, for example, about 4.2. And stirring for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, the chemical reaction shown below proceeds between the chromium ions and calcium carbonate in the third treatment liquid, the chromium ions are changed to chromium hydroxide, and the chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed is obtained. It is formed.
Cr ³⁺ + 3Cl ⁻ + 3CaCO ₃ + 3H ₂ O
→ Cr (OH) ₃ ↓ + 3Cl ⁻ + 3Ca ²⁺ + 3HCO ₃ ^{− *}
Herein, HCO ₃ ^{- *} may, HCO ₃ ^- is obtained by collectively underwater carbon dioxide produced by the decomposition of various carbon component and calcium carbonate are dissolved, such as. Further, the reason why the pH was set to 3 to 5 is that when the pH is less than 3, the neutralization amount of chromium decreases, and when the pH exceeds 5, zinc hydroxide is generated together with chromium hydroxide. And by using calcium carbonate which is a weak alkali, when carrying out chromium neutralization, the production | generation of a local high pH area | region can be suppressed and the production | generation of zinc hydroxide can be prevented.

Subsequently, the temperature of the chromium hydroxide dispersion treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the chromium hydroxide dispersion treatment liquid to 600 mV or more for a predetermined time (20 Stir for ~ 60 minutes, eg 25 minutes. As a result, the chemical reaction shown below proceeds, and all the ferrous ions in the chromium hydroxide dispersion treatment liquid are oxidized to change to ferric ions, and remain in the chromium hydroxide dispersion treatment liquid. Organic substances are also oxidized and decomposed.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance. Further, when a large amount of organic substance is present in the chromium hydroxide dispersion treatment liquid, ferrous iron is added. Thereby, a large amount of hydroxy radicals are generated, and the decomposition of the organic matter is promoted.

Then, the temperature of the chromium hydroxide dispersion treatment liquid is maintained at 60 ° C. or more and less than 100 ° C., for example, 80 ° C., and a weak alkali agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less. Adjust to about 3.5 and stir for a predetermined time (20 to 60 minutes, for example, 30 minutes) (iron neutralization). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the chromium hydroxide dispersion treatment liquid, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Moreover, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only a part of the ferric ion became ferric hydroxide, and when the pH exceeded 5, the ferric hydroxide was used. This is because zinc hydroxide is generated. By setting the temperature to 60 ° C. or higher and lower than 100 ° C., preferably 75 ° C. or higher and 85 ° C. or lower, the production rate of ferric hydroxide can be increased. By agglomerating chromium hydroxide present in the dispersion treatment liquid as a nucleus, particles of ferric hydroxide starch can be coarsened. For this reason, after a predetermined time has passed, the filterability when a liquid containing ferric hydroxide starch is solid-liquid separated by, for example, a filter press is improved, and the ferric hydroxide starch is converted to chromium hydroxide. The fourth treatment liquid can be easily recovered by separating it as a cake together with the starch (the fourth step). Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

The temperature of the recovered fourth treatment liquid is kept at 20 to 80 ° C., preferably 60 ° C. or more, and slaked lime is added as an alkaline agent to adjust the pH to 9 or more and 11 or less, for example, about 9.5 for a predetermined time (15 Stir (Zinc neutralization) for ~ 60 minutes, e.g., 30 minutes. Thereby, the chemical reaction shown below progresses between the zinc ions and the slaked lime in the fourth treatment liquid, and the zinc ions change to zinc hydroxide.
Zn ²⁺ + 2Cl ⁻ + Ca (OH) ₂ → Zn (OH) ₂ ↓ + Ca ²⁺ + 2Cl ⁻
Here, the reason why the pH is set to 9 to 11 is that when the pH is less than 9, only a part of zinc becomes zinc hydroxide, and when the pH exceeds 11, the zinc hydroxide is redissolved. Moreover, the production | generation speed | rate of zinc hydroxide can be enlarged by making temperature into 60 degreeC or more, and the particle | grains of the zinc hydroxide starch to produce | generate can be coarsened. For this reason, after a predetermined time, the filterability when the liquid containing zinc hydroxide starch is solid-liquid separated by, for example, a filter press can be improved, and the zinc hydroxide starch can be easily recovered as a cake. Thus, the fifth processing liquid can be easily separated (the fifth step). The separated cake is washed with washing water to reduce the residual liquid adhering to the cake side. Thereby, the amount of impurities contained in zinc hydroxide can be reduced.
Then, the separated fifth treatment liquid (process wastewater) is supplied to the water treatment facility and processed so that the chemical oxygen demand (COD), pH, etc. are below the emission standard value. Drain.

As shown in FIGS. 15 and 16, the waste sludge recycling process method according to the sixth embodiment of the present invention is the fourth of the waste liquid sludge recycling process method according to the fifth embodiment. Instead of the process, a weak alkaline agent is added to the third treatment liquid as a pH adjuster to adjust the pH, and a chromium neutralization treatment is performed by changing chromium ions in the third treatment liquid to chromium hydroxide. Part of the organic matter present in the chromium removal solution by separating the chromium hydroxide starch into a chromium removal solution and adding an oxidizing agent to the chromium removal solution to maintain the ORP at 400 mV to 500 mV. The first ferrous ions present in the chromium removal solution are oxidized to ferric ions, and a weak alkaline agent is added to adjust the pH to ferric hydroxide. Iron neutralization treatment, ferric hydroxide The dispersed dispersion is made into a dispersed dispersion, and an oxidizing agent is added to the dispersion to keep ORP at 600 mV or more to decompose the remaining organic matter remaining in the dispersion and to oxidize the remainder of ferrous ions in the dispersion. Then, ferric hydroxide starch is obtained by performing a second iron neutralization treatment in which the pH is adjusted by adding a weak alkaline agent to the dispersion treatment liquid and changing to ferric hydroxide. It is characterized in that the step 4A is carried out by separating the ferric hydroxide starch into a fourth treatment liquid containing zinc, and the other steps are the waste liquid sludge according to the fifth embodiment. This is substantially the same as the recycling processing method. For this reason, only the 4th A process is explained.

In the 4A step, first, the temperature of the third treatment liquid is maintained at 30 to 80 ° C., for example, 60 ° C., and calcium carbonate is added as a weak alkaline agent to adjust the pH to 3 or more and 5 or less, for example, about 4.2. And stirring for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, a chemical reaction proceeds between the chromium ions and calcium carbonate in the third treatment liquid, and the chromium ions are changed to chromium hydroxide to form a liquid containing chromium hydroxide starch. And after predetermined time progress, the liquid containing a chromium hydroxide starch is solid-liquid separated, for example with a filter press, chromium hydroxide starch is isolate | separated as a cake, and chromium removal liquid is collect | recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

Next, the temperature of the chromium removal liquid from which the chromium hydroxide starch is separated is maintained at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent, so that the ORP of the chromium removal liquid is about 400 to 500 mV, for example, about 450 mV. And stirring for a predetermined time (3 to 10 minutes, for example, 6 minutes). As a result, the chemical reaction shown below proceeds, a part of the organic matter present in the chromium removal solution is decomposed, and a part of the ferrous ions present in the chromium removal solution is oxidized to ferric ions. become.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

And the temperature of chromium removal liquid is maintained at 20-80 degreeC, for example, 60 degreeC, calcium carbonate is added as a weak alkaline agent, pH is adjusted to 2.5 or more and 5 or less, for example, about 3.5, and predetermined time. Stir (3 to 10 minutes, for example, 6 minutes) (first iron neutralization treatment). As a result, the chemical reaction shown below proceeds between the ferric ion and calcium carbonate in the chromium removal solution, and the ferric ion is changed to ferric hydroxide. Becomes a dispersion treatment liquid in which ferrous hydroxide seeds are produced.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Subsequently, the temperature of the dispersion treatment liquid is kept at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the dispersion treatment liquid to 600 mV or more for a predetermined time (20 to 60 minutes, for example, 25 Stir for minutes). As a result, the chemical reaction shown below proceeds, and all the ferrous ions in the dispersion treatment liquid are oxidized to change to ferric ions, and the organic matter remaining in the dispersion treatment liquid is also oxidized and decomposed. To do.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

Then, the temperature of the dispersion treatment liquid is kept at 60 ° C. or less and less than 100 ° C., for example, 80 ° C., and a weak alkali agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less, for example, 3.5 It adjusts to a grade and it stirs for the predetermined time (20-60 minutes, for example, 30 minutes) (2nd iron neutralization process). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the dispersion treatment liquid, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

In addition, the pH was set to 2.5 to 5 because when the pH was less than 2.5, only a portion of the ferric ion became ferric hydroxide, and when the pH exceeded 5, This is because zinc hydroxide is generated. By setting the temperature to 60 ° C. or more and less than 100 ° C., preferably 75 ° C. or more and 85 ° C. or less, the production rate of ferric hydroxide can be increased, and the produced ferric hydroxide is contained in the dispersion treatment liquid. By agglomerating the existing ferric hydroxide as a nucleus, the ferric hydroxide starch particles can be coarsened. For this reason, after a predetermined time has passed, the filterability when the liquid containing ferric hydroxide starch is solid-liquid separated by, for example, a filter press is improved, and the ferric hydroxide starch is separated as a cake. The fourth treatment liquid can be easily recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away. This further increases the recovery rate of each metal ion.

As shown in FIG. 17, in the modified example of the waste sludge recycling treatment method according to the sixth embodiment of the present invention, a weak alkaline agent is used as a pH adjuster in the third treatment liquid instead of the 4A step. Is added to adjust the pH, and chromium neutralization treatment is performed by changing chromium ions in the third treatment liquid to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to remove the chromium hydroxide. Then, an oxidant is added to the chrome removal liquid to maintain ORP at 600 mV or more to decompose organic substances present in the chrome removal liquid and oxidize ferrous ions in the chrome removal liquid to ferric ions, Then, a third alkali neutralization treatment is performed by adding a weak alkaline agent as a pH adjuster to adjust the pH to ferric hydroxide to produce ferric hydroxide starch. The fourth treatment liquid containing zinc is separated. And performing the 4B step. Hereinafter, the step 4B will be described.

In about 4B, first, the temperature of the third treatment liquid is maintained at 30 to 80 ° C., for example, 60 ° C., and a weak alkaline agent, for example, calcium carbonate is added to adjust the pH to 3 or more and 5 or less, for example, about 4.2. Adjust and stir for a predetermined time (20 to 60 minutes, for example, 30 minutes) (chromium neutralization). As a result, the chromium ion is changed to chromium hydroxide, and a liquid containing chromium hydroxide starch is formed. And after predetermined time progress, the liquid containing a chromium hydroxide starch is solid-liquid separated, for example with a filter press, chromium hydroxide starch is isolate | separated as a cake, and chromium removal liquid is collect | recovered. Here, the separated cake is washed with washing water so that each metal ion remaining on the cake side is washed away.

Next, the temperature of the chromium removal liquid from which the chromium hydroxide starch has been separated is maintained at 20 to 80 ° C., for example, 60 ° C., and hydrogen peroxide is added as an oxidizing agent to adjust the ORP of the chromium removal liquid to 600 mV or more to obtain a predetermined value. Stir for time (20-60 minutes, eg 25 minutes). As a result, the chemical reaction shown below proceeds and all the ferrous ions in the chromium removal solution are oxidized to ferric ions, and organic substances present in the chromium removal solution are also oxidized and decomposed. To do.
2Fe ²⁺ + 4Cl ⁻ + H ₂ O ₂
→ 2Fe ³⁺ + 4Cl ⁻ + 2OH ⁻ + 2 · OH (Ferrous iron oxidation reaction)
R + · OH → xCO ₂ + yH ₂ O (organic matter decomposition reaction)
Here, .OH represents a hydroxy radical, and R represents an organic substance.

Then, the temperature of the chromium removal solution is kept at 60 ° C. or less and less than 100 ° C., for example, 80 ° C., and a weak alkaline agent such as calcium carbonate is added as a pH adjuster to adjust the pH to 2.5 or more and 5 or less, for example, 3.5 It adjusts to a grade and it stirs for a predetermined time (20-60 minutes, for example, 30 minutes) (3rd iron neutralization process). Thereby, the chemical reaction shown below progresses between the ferric ion and calcium carbonate in the chromium removal solution, and the ferric ion changes to ferric hydroxide.
Fe ³⁺ + 2Cl ⁻ + OH ⁻ + CaCO ₃ + 2H ₂ O
→ Fe (OH) ₃ ↓ + Ca ²⁺ + 2Cl ⁻ + H ₂ CO ₃ ^*
Here, H ₂ CO ₃ ^* is a general term for various carbonic acid components dissolved in water such as H ₂ CO ₃ and carbon dioxide gas generated by decomposition of calcium carbonate.

Moreover, the pH was adjusted to 2.5 to 5 because when the pH was less than 2.5, only a part of the ferric ion became ferric hydroxide, and when the pH exceeded 5, the ferric hydroxide was used. This is because zinc hydroxide is generated. By setting the temperature to 60 ° C. or more and less than 100 ° C., preferably 75 ° C. or more and 85 ° C. or less, the production rate of ferric hydroxide can be increased, and the particles of ferric hydroxide starch are coarsened. be able to.

The waste liquid sludge recycling method according to the seventh embodiment of the present invention shown in FIG. 18 and FIG. 19 is a process in which nickel, copper, zinc, iron, and chromium are all present in a hydroxide state. Sludge dissolution treatment is performed by adding hydrochloric acid as an inorganic acid to component-based plating waste sludge (hereinafter referred to simply as "sludge") to form a dissolution treatment product. The insoluble matter is removed from the dissolution treatment product, and nickel, copper, zinc, iron And the first step of providing an insoluble matter removal treatment to obtain a first treatment liquid mixed with chromium, and adjusting the oxidation-reduction potential and pH by adding hydrochloric acid as an example of iron powder and acid to the first treatment solution, Replace the copper ions and iron in the first treatment liquid to form copper-adhered iron powder with copper deposited on the surface (copper recovery cementation), separate the copper-adhered iron powder, and add nickel, zinc, iron, and chromium A second step of containing a second treatment liquid; Add iron powder and hydrochloric acid as an example of acid to the second treatment liquid to adjust the oxidation-reduction potential and pH, replace the nickel ions and iron in the second treatment liquid and deposit nickel on the surface. Forming (nickel recovery cementation), separating the nickel-adhered iron powder into a third treatment liquid containing zinc, iron and chromium, and a weak alkaline agent as a pH adjuster in the third treatment liquid, for example, Then, the pH is adjusted by adding calcium carbonate, and the chromium neutralization treatment is performed to change the chromium ions in the third treatment liquid to chromium hydroxide to obtain a chromium hydroxide dispersion treatment liquid in which chromium hydroxide is dispersed. Hydrogen peroxide is added to the treatment liquid as an oxidizing agent to oxidize ferrous ions in the chromium hydroxide dispersion treatment liquid to ferric ions, and then a weak alkaline agent such as calcium carbonate as a pH adjuster. To adjust the pH and neutralize the ferric hydroxide by changing ferric ions to ferric hydroxide to produce ferric hydroxide starch. And a fourth step of separating into a fourth treatment liquid containing zinc, and adjusting the pH by adding, for example, slaked lime as an alkaline agent to the fourth treatment liquid, and converting zinc ions in the fourth treatment liquid to zinc hydroxide A zinc neutralization treatment to produce a zinc hydroxide starch, a fifth treatment solution for separating the zinc hydroxide starch and removing the zinc to form a fifth treatment solution, and a multi-component plating waste solution It is characterized by the separate recovery of nickel, copper, zinc, iron and chromium from sludge. Here, the organic substance contained in the sludge described in the fifth embodiment is decomposed simultaneously when the sludge is dissolved in an inorganic acid and when ferrous ions are oxidized to ferric ions. Therefore, the waste sludge recycling method according to the seventh embodiment is substantially the same as the waste sludge recycling method according to the fifth embodiment except for the organic matter decomposition treatment. It can be.

Further, the waste sludge recycling treatment method according to the eighth embodiment of the present invention shown in FIGS. 20 and 21 is the third step of the waste liquid sludge recycling treatment method according to the seventh embodiment. Instead of adding a weak alkaline agent as a pH adjuster to the fourth treatment liquid, the pH is adjusted, and chromium neutralization treatment is performed by changing chromium ions in the third treatment liquid to chromium hydroxide to perform chromium hydroxide starch. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution to maintain the ORP at 400 mV or more and 500 mV or less to remove ferrous ions present in the chromium removal solution. Partly oxidized to ferric ions, further weak alkaline agent added to adjust pH to ferric hydroxide to perform first iron neutralization treatment, ferric hydroxide was dispersed A dispersion treatment liquid is obtained, and an oxidizing agent is added to the dispersion treatment liquid. P is maintained at 600 mV or more, and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions. Then, a weak alkaline agent is added to the dispersion treatment liquid to adjust the pH, thereby adding a second hydroxide. 2nd iron neutralization process which changes to iron is performed, ferric hydroxide starch is produced | generated, and the 4th A process which makes a 4th process liquid which isolate | separates ferric hydroxide starch and contains zinc is performed The waste sludge recycling treatment method according to the eighth embodiment is substantially the same except for the waste liquid sludge recycling treatment method and the organic matter decomposition treatment according to the sixth embodiment. Can be the same.

Further, in the modified example of the waste liquid sludge recycling treatment method of the eighth embodiment shown in FIG. 22, instead of the 4A step, a weak alkaline agent is added to the third treatment liquid as a pH adjuster to adjust the pH. The chromium ion in the third treatment liquid is changed to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to form a chromium removal liquid. Add an oxidizing agent to keep ORP at 600 mV or more to oxidize ferrous ions in the chromium removal solution to ferric ions, and then adjust the pH by adding a weak alkaline agent as a pH adjusting agent. A third iron neutralization treatment that converts to ferric hydroxide is performed to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to form a fourth treatment solution containing zinc. The waste liquid according to the sixth embodiment is characterized by performing the 4B process. It can be substantially identical except for the decomposition process of the variation example and organic matter recycling processing method sludge. For this reason, the explanation about the recycling method of waste liquid sludge of the 8th embodiment and its modification is omitted.

Next, examples carried out for confirming the effects of the present invention will be described.
Copper, chromium and iron, nickel, iron, and zinc were separately collected in order from the multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, chromium, and organic matter. First, 112.14 g of water was added to multi-component plating waste liquid sludge (167.86 g, solid content was 50 g) to prepare a slurry. Table 1 shows the composition of the multicomponent plating waste liquid sludge. T. T. C is the total carbon content.

Subsequently, while heating so that the temperature of the slurry became 80 ° C., 220 g of 15% hydrochloric acid was added so that the pH was about 1.0, and the slurry was stirred for 60 minutes to dissolve the sludge. The temperature at the start of the sludge dissolution treatment was 81.1 ° C., the ORP was 515 mV, and the pH was 1.03. 50 g of make-up water was added 20 minutes after the start. Thereby, temperature fell to 78.1 degreeC, ORP was 481 mV, and pH became 1.11. After 40 minutes from the start of the sludge dissolution treatment, the temperature was 84.0 ° C., the ORP was 487 mV, the pH was 1.10, and the sludge dissolution treatment was completed (60 minutes after the start of the sludge dissolution treatment). 0.5 ° C., ORP was 478 mV, and pH was 1.06. From the quantification of the total carbon amount of the dissolved processed product after the sludge dissolution treatment, it was confirmed that 32% of the total organic matter contained in the sludge was decomposed by the sludge dissolution treatment. The dissolved treated product was vacuum filtered to collect the filtrate, and 100 g of washing water was supplied to the insoluble matter and vacuum filtration was performed again to collect the washing water and mixed with the filtrate to obtain a first treatment liquid. The insoluble content and the composition of the first treatment liquid are shown in Tables 1 and 2, respectively (first step).

While adding 15.0 g of iron powder to the recovered first treatment liquid (518.83 g), hydrochloric acid is added so that the pH is 2 or less, and the temperature of the first treatment liquid is kept at 40 ° C. Then, stirring was performed for 15 minutes so that the ORP became −400 mV or more, and copper was deposited on the surface of the iron powder to form a copper-adhered iron powder. The ORP of the liquid at the time of iron powder charging was 355 mV, the pH was 1.09, and the temperature was 37.7 ° C. The ORP of the liquid after 15 minutes was −88 mV, the pH was 1.10, and the temperature was 40. 7 ° C. Next, the filtrate is recovered by vacuum filtration, and 25 g of cleaning water is supplied to the separated copper-attached iron powder, and vacuum filtration is performed again to recover the cleaning water, which is mixed with the filtrate and mixed with the second treatment liquid. did. The compositions of the copper-adhered iron powder and the second treatment liquid are shown in Tables 1 and 2, respectively (the second step).

While heating so that the temperature of the recovered second treatment liquid (511.23 g) is 60 ° C., 15.26 g of calcium carbonate is added to adjust the pH to about 4.2 and stirred for 30 minutes to remove chromium ions. Chromium neutralization was performed to change to chromium hydroxide. The ORP at the start of chromium neutralization was −93 mV, the pH was 4.03, and the temperature was 64.3 ° C. The ORP when the neutralization of chromium was completed was 52 mV, the pH was 4.19, and the temperature was 60. It was 4 ° C. Next, while heating to a temperature of 60 ° C., 8.64 g of 35% aqueous hydrogen peroxide was added and stirred for 20 minutes to oxidize ferrous ions to ferric ions. The ORP at the start of oxidation of ferrous ions was 627 mV, the pH was 2.27, the temperature was 63.8 ° C, the ORP after the oxidation was 603 mV, the pH was 2.16, and the temperature was 61.5 ° C. It was. Subsequently, 4.78 g of calcium carbonate is added so that the temperature is kept at 60 ° C. so that the pH is about 3.5, and then the temperature is kept at 80 ° C. and stirred for 30 minutes to hydroxylate ferric ions. It was changed to ferric iron (first iron neutralization treatment). The ORP at the start of the first iron neutralization treatment is 459 mV, the pH is 3.41, the temperature is 61.1 ° C., the ORP at the end of the first iron neutralization treatment is 276 mV, and the pH is 3. 49, the temperature was 82.0 ° C.
And the liquid after completion | finish of a 1st iron neutralization process is vacuum-filtered, filtrate is collect | recovered, 150g of washing water is supplied to the isolate | separated mixture of chromium hydroxide and ferric hydroxide, and it vacuum-filters again. The washing water was collected and mixed with the filtrate to obtain a third treatment liquid. The composition of the mixed starch of chromium hydroxide and ferric hydroxide and the composition of the third treatment liquid are shown in Tables 1 and 2, respectively (the third step).

457.0 g of iron powder is added to the recovered third treatment liquid (456.66 g), and 91.4 g of 15% hydrochloric acid is added so that the pH is 5 or less. Further, the temperature of the third treatment liquid is increased. It was kept at 60 ° C. and stirred for 180 minutes so that the ORP was −450 mV, and nickel was deposited on the surface of the iron powder to form nickel-adhered iron powder (nickel recovery cementation). The ORP of the liquid at the time of iron powder charging was −497 mV, the pH was 5.32, and the temperature was 62.8 ° C. The ORP of the liquid after 60 minutes was −566 mV, the pH was 4.82, and the temperature was 60. The ORP of the solution after lapse of 120 ° C. at −5 ° C. is −563 mV, the pH is 4.87, the temperature is 61.2 ° C., the ORP of the solution after 180 minutes (at the end of nickel recovery cementation) is −568 mV, pH Was 4.86 and the temperature was 61.3 ° C. Next, the filtrate is recovered by vacuum filtration, and 100 g of cleaning water is supplied to the separated nickel-adhered iron powder, and vacuum filtration is performed again to recover the cleaning water, which is mixed with the filtrate and mixed with the fourth treatment liquid. did. The compositions of the nickel-adhered iron powder and the fourth treatment liquid are shown in Tables 1 and 2, respectively (the fourth step).

Part of ferrous ions in the fourth treatment liquid by maintaining the temperature of the fourth treatment liquid (445.22 g) at 65 ° C., adding 12.82 g of 35% hydrogen peroxide and holding ORP at 450 mV for 6 minutes. Was oxidized to ferric ions. Next, 5.65 g of calcium carbonate is added to adjust the pH to 3.5, and the temperature is maintained at 60 ° C. for 6 minutes to change the ferric ion to ferric hydroxide and disperse ferric hydroxide. A neutralizing solution was formed. Subsequently, the iron neutralization treatment solution was brought to 60 ° C., 34.43 g of 35% hydrogen peroxide solution was added, and the ORP was raised to 600 mV or more and held for 20 minutes. Here, when ORP is held at 450 mV for 6 minutes, ORP is 450 mV, pH is 2.03, temperature is 65.0 ° C., and the iron neutralization treatment solution formed by adding calcium carbonate and holding for 6 minutes ORP is 158 mV, pH is 3.50, temperature is 61.4 ° C., ORP is 654 mV, pH is 1.85, temperature is 71.4 ° C. when hydrogen peroxide solution is added to the iron neutralization solution. Then, the hydrogen peroxide solution was added to the iron neutralization treatment solution, and after 20 minutes, the ORP of the intermediate treatment solution was 641 mV, the pH was 1.70, and the temperature was 61.8 ° C.

Then, 17.48 g of calcium carbonate is added so that the pH of the intermediate treatment solution becomes about 3.5, and then the temperature is kept at 80 ° C. and stirred for 60 minutes, and the ferric ion is changed to ferric hydroxide. (Second iron neutralization treatment). The ORP at the start of the second iron neutralization treatment is 332 mV, the pH is 3.47, the temperature is 80.1 ° C., the ORP at the end of the second iron neutralization treatment is 243 mV, and the pH is 3. 50, the temperature was 80.5 ° C.
And the liquid after completion | finish of a 2nd iron neutralization process is vacuum-filtered, filtrate is collect | recovered, 100g of washing water is supplied to the separated ferric hydroxide starch, vacuum filtration is performed again, and washing water is supplied. It collect | recovered and mixed with the filtrate, and it was set as the 5th process liquid. The compositions of ferric hydroxide starch and the fifth treatment liquid are shown in Tables 1 and 2, respectively (the fifth step).

Maintaining the temperature of the recovered fifth treatment liquid (325.15 g) at 60 ° C., adding 9.78 g of 48% sodium hydroxide so that the pH is about 10, and stirring for 30 minutes, (Zinc neutralization treatment). The ORP of the liquid immediately after adding sodium hydroxide is −520 mV, the pH is 10.43, the temperature is 68.5 ° C., and the ORP of the liquid after 30 minutes (when the zinc neutralization treatment is completed) is −508 mV, The pH was 10.36 and the temperature was 66.3 ° C. Next, the filtrate is recovered by vacuum filtration, and 100 g of washing water is supplied to the separated zinc hydroxide starch, vacuum filtration is performed again to collect the washing water, and the filtrate is mixed with the filtrate. It was. The compositions of the zinc hydroxide starch and the sixth treatment liquid are shown in Tables 1 and 2, respectively (the sixth step).
From the composition of the sixth treatment liquid, it was confirmed that all of nickel, copper, zinc, iron, chromium, and organic substances originally contained in the multicomponent plating waste liquid sludge were removed. In addition, recovery of each metal obtained from the collected copper-adhered iron powder, mixed starch of chromium hydroxide and ferric hydroxide, nickel-adhered iron powder, ferric hydroxide starch, and zinc hydroxide starch The rates were 91.0% for nickel, 99.4% for chromium, 96.4% for copper, and 64.1% for zinc. In addition, since iron melt | dissolves in a 1st process liquid when collect | recovering copper by a 2nd process and a 3rd process liquid when collect | recovering nickel by a 4th process, respectively, the recovery rate of iron is not calculated | required.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, The change in the range which does not change the summary of invention is possible, Each above-mentioned embodiment is possible. A case where the recycling method for multi-component plating waste liquid sludge according to the present invention is configured by combining some or all of the forms and modifications is also included in the scope of the present invention.
For example, in the first to eighth embodiments, multi-component plating waste liquid sludge is dissolved in hydrochloric acid in the first step, but sulfuric acid can also be used. In this case, the sludge dissolution treatment is performed under the conditions of pH of 0.5 or more and 2 or less, and the temperature of 80 ° C. or more and less than 100 ° C., and between the sludge dissolution treatment and the insoluble matter removal treatment, For example, it is necessary to provide a sulfate radical removal treatment in which calcium chloride is added to remove the sulfate radical in the dissolved treatment product as gypsum by setting the pH to 1 to 2 and the temperature to 80 ° C. to less than 100 ° C.

It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 1st Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 2nd Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 3rd Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 4th Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 5th Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 6th Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 7th Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge which concerns on the 8th Embodiment of this invention. It is partial process explanatory drawing of the recycling processing method of the multicomponent plating waste liquid sludge. It is partial process explanatory drawing which concerns on the modification of the recycling processing method of the multi-component plating waste liquid sludge.

Claims (44)

Sludge dissolution treatment is performed by adding an inorganic acid to a multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, chromium, and organic matter to dissolve the multi-component plating waste liquid sludge to form a dissolved processed product. A first step of providing an insoluble matter removal treatment for removing the insoluble matter from the dissolved treatment product to obtain a first treatment liquid in which a part of nickel, copper, zinc, iron, chromium, and organic matter is mixed;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step of forming a second treatment liquid containing zinc, iron, chromium, and organic matter;
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjuster to the second treatment solution to adjust the pH, and performing chromium neutralization treatment to change chromium ions in the second treatment solution to chromium hydroxide. And an oxidizing agent is added to the chromium hydroxide dispersion treatment solution to decompose organic substances present in the chromium hydroxide dispersion treatment solution and oxidize ferrous ions in the chromium hydroxide dispersion treatment solution. Then, ferric hydroxide starch is produced by performing a first iron neutralization treatment in which a ferric ion is added and then a pH adjusting agent is added to adjust the pH to convert the ferric ion to ferric hydroxide. A third step of separating the ferric hydroxide starch together with the chromium hydroxide into a third treatment liquid containing nickel and zinc;
The iron powder is added to the third treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the third treatment liquid are replaced with iron, and the nickel-attached iron powder on which nickel is deposited is separated, and zinc is separated. And a fourth step as a fourth treatment liquid containing iron,
An intermediate treatment solution is prepared by oxidizing the ferrous ions in the fourth treatment solution to ferric ions, and a pH adjuster is added to the intermediate treatment solution to adjust the pH. A second iron neutralization treatment for converting ferric ions to ferric hydroxide is performed to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. A fifth step as a treatment liquid;
Zinc neutralization treatment is performed by adjusting the pH of the fifth treatment liquid and changing zinc ions in the fifth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And a sixth step of making a sixth treatment liquid from which zinc has been removed,
An organic material is decomposed from the multi-component plating waste liquid sludge to separate and recover nickel, copper, zinc, iron, and chromium, and a method for recycling multi-component plating waste sludge. The recycling method for multi-component plating waste liquid sludge according to claim 1, wherein the second iron neutralization treatment is performed at 60 ° C or higher, preferably 75 ° C or higher, less than 100 ° C, preferably 85 ° C or lower. A recycling method for multi-component plating waste sludge characterized by the above. 3. The recycling method for multi-component plating waste liquid sludge according to claim 1, wherein the intermediate treatment is performed by adding an oxidizing agent to the fourth treatment liquid so that an oxidation-reduction potential is 600 mV or more. A method for recycling a multi-component plating waste liquid sludge, characterized in that the ferrous ions in the fourth treatment liquid are all oxidized to ferric ions. 3. The recycling method for multi-component plating waste liquid sludge according to claim 1, wherein the intermediate treatment is performed by adding an oxidizing agent to the fourth treatment liquid so that an oxidation-reduction potential is 400 mV or more. A part of the ferrous ions in the fourth treatment solution is oxidized to a ferric ion by holding at 500 mV or less, and the pH is adjusted by adding a pH adjusting agent to convert the ferric ions to the second hydroxide. As an iron neutralization treatment liquid in which ferric hydroxide is dispersed by performing iron neutralization to convert to iron, an oxidizing agent is added to the iron neutralization treatment solution to maintain a redox potential at 600 mV or more, thereby neutralizing the iron. A recycling method for multi-component plating waste liquid sludge, characterized in that all ferrous ions in the treatment liquid are oxidized to ferric ions. 5. The recycling method for multicomponent plating waste liquid sludge according to claim 4, wherein the oxidizing agent added to the iron neutralization processing liquid is hydrogen peroxide. Processing method. The multicomponent plating waste liquid sludge recycling treatment method according to any one of claims 3 to 5, wherein the oxidizing agent added to the fourth treatment liquid is hydrogen peroxide. Recycling method of plating waste liquid sludge. The multicomponent plating waste liquid sludge recycling treatment method according to any one of claims 1 to 6, wherein ferrous iron is added together with an oxidizing agent to the chromium hydroxide dispersion treatment liquid. Recycling method of component plating waste liquid sludge. The recycling method for multi-component plating waste liquid sludge according to any one of claims 1 to 7, wherein an oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide. Recycling method of component plating waste liquid sludge. The recycling method of the multicomponent plating waste liquid sludge according to any one of claims 1 to 8, wherein the first iron neutralization treatment is 60 ° C or higher, preferably 75 ° C or higher, and 100 ° C. Less preferably, it is performed at 85 degrees C or less, The recycling processing method of the multicomponent type plating waste liquid sludge characterized by the above-mentioned. In the recycling processing method of the multi-component plating waste liquid sludge according to any one of claims 1 to 6, a pH adjuster is added to the second treatment liquid instead of the third step to adjust the pH. Then, a chromium neutralization treatment is performed by changing chromium ions in the second treatment liquid to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to form a chromium removal liquid. An oxidizing agent is added to the removal liquid to keep the oxidation-reduction potential at 400 mV or more and 500 mV or less to decompose organic substances present in the chromium removal liquid and to remove some of the ferrous ions present in the chromium removal liquid. Dispersion treatment liquid in which ferric hydroxide is dispersed by performing iron neutralization treatment of 1A, which is oxidized to ferric ions, and further adjusted to pH by adding a pH adjuster to change to ferric hydroxide And oxidize by adding an oxidizing agent to the dispersion treatment liquid. While maintaining the original potential at 600 mV or more, the organic substances present in the dispersion treatment liquid are decomposed and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions. A ferric hydroxide starch is formed by adding a pH adjuster to adjust the pH to ferric hydroxide to produce ferric hydroxide starch, and separating the ferric hydroxide starch. A method of recycling the sludge of multi-component plating waste liquid, comprising performing step 3A of making a third treatment solution containing nickel and zinc. The recycling method for multi-component plating waste liquid sludge according to claim 10, wherein the iron neutralization treatment of 1B is performed at 60 ° C or higher, preferably 75 ° C or higher, less than 100 ° C, preferably 85 ° C or lower. A recycling method for multi-component plating waste sludge characterized by the above. In the recycling processing method of the multi-component plating waste liquid sludge according to any one of claims 1 to 6, a pH adjuster is added to the second treatment liquid instead of the third step to adjust the pH. Then, a chromium neutralization treatment is performed by changing chromium ions in the second treatment liquid to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to form a chromium removal liquid. An oxidizing agent is added to the removal liquid to maintain an oxidation-reduction potential at 600 mV or more to decompose organic substances present in the chromium removal liquid and oxidize ferrous ions in the chromium removal liquid to ferric ions. Next, a 1 C iron neutralization treatment is performed by adding a pH adjuster to adjust the pH to ferric hydroxide to produce a ferric hydroxide starch. Separately to be a third treatment liquid containing nickel and zinc Recycling processing method of the multi-component plating waste sludge and performing 3B step. 13. The recycling method for multicomponent plating waste liquid sludge according to claim 12, wherein the 1C iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. Sludge dissolution treatment is performed by adding an inorganic acid to multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, and chromium to dissolve the multi-component plating waste liquid sludge to form a dissolved treatment product, and the dissolution treatment A first step of providing an insoluble content removal treatment for removing a insoluble content from the product to obtain a first treatment liquid in which nickel, copper, zinc, iron, and chromium are mixed;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step as a second treatment liquid containing zinc, iron, and chromium;
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjuster to the second treatment solution to adjust the pH, and performing chromium neutralization treatment to change chromium ions in the second treatment solution to chromium hydroxide. And oxidize the chromium hydroxide dispersion treatment solution to oxidize ferrous ions in the chromium hydroxide dispersion treatment solution to ferric ions, and then adjust the pH by adding a pH adjuster. Then, ferric hydroxide starch is produced by performing a first iron neutralization treatment for converting ferric ions to ferric hydroxide, and separating the ferric hydroxide starch together with the chromium hydroxide. And a third step of making a third treatment liquid containing nickel and zinc,
The iron powder is added to the third treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the third treatment liquid are replaced with iron, and the nickel-attached iron powder on which nickel is deposited is separated, and zinc is separated. And a fourth step as a fourth treatment liquid containing iron,
An intermediate treatment solution is prepared by oxidizing the ferrous ions in the fourth treatment solution to ferric ions, and a pH adjuster is added to the intermediate treatment solution to adjust the pH. A second iron neutralization treatment for converting ferric ions to ferric hydroxide is performed to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. A fifth step as a treatment liquid;
Zinc neutralization treatment is performed by adjusting the pH of the fifth treatment liquid and changing zinc ions in the fifth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And a sixth step of making a sixth treatment liquid from which zinc has been removed,
A method for recycling a multicomponent plating waste liquid sludge, wherein nickel, copper, zinc, iron, and chromium are separated and recovered from the multicomponent plating waste liquid sludge. 15. The recycling method for multi-component plating waste liquid sludge according to claim 14, wherein the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. 16. The recycling method for multi-component plating waste liquid sludge according to claim 14, wherein the intermediate treatment is performed by adding an oxidizing agent to the fourth treatment liquid so that the oxidation-reduction potential is 600 mV or more. A method for recycling a multi-component plating waste liquid sludge, characterized in that the ferrous ions in the fourth treatment liquid are all oxidized to ferric ions. The recycling process for multicomponent plating waste liquid sludge according to claim 16, wherein the oxidizing agent added to the fourth processing liquid is hydrogen peroxide. Method. 16. The recycling method for multi-component plating waste liquid sludge according to claim 14, wherein the intermediate treatment is performed by adding an oxidizing agent to the fourth treatment liquid so that an oxidation-reduction potential is 400 mV or more. A part of the ferrous ions in the fourth treatment solution is oxidized to a ferric ion by holding at 500 mV or less, and the pH is adjusted by adding a pH adjusting agent to convert the ferric ions to the second hydroxide. As an iron neutralization treatment liquid in which ferric hydroxide is dispersed by performing iron neutralization to convert to iron, an oxidizing agent is added to the iron neutralization treatment solution to maintain a redox potential at 600 mV or more, thereby neutralizing the iron. A recycling method for multi-component plating waste liquid sludge, characterized in that all ferrous ions in a processing solution are oxidized to ferric ions. The multi-component plating waste liquid sludge recycling treatment method according to claim 18, wherein the oxidizing agent added to the fourth treatment liquid and the iron neutralization treatment liquid is hydrogen peroxide. A method for recycling waste sludge. 20. The recycling method for multi-component plating waste liquid sludge according to claim 14, wherein an oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide. Recycling method of component plating waste liquid sludge. The recycling method of the multi-component plating waste liquid sludge according to any one of claims 14 to 20, wherein the first iron neutralization treatment is 60 ° C or higher, preferably 75 ° C or higher, and 100 ° C. Less preferably, it is performed at 85 degrees C or less, The recycling processing method of the multicomponent type plating waste liquid sludge characterized by the above-mentioned. In the recycling method of the multi-component plating waste liquid sludge according to any one of claims 14 to 19, the pH is adjusted by adding a pH adjuster to the second treatment liquid instead of the third step. Then, a chromium neutralization treatment is performed by changing chromium ions in the second treatment liquid to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to form a chromium removal liquid. An oxidizing agent is added to the removal liquid, and the oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to oxidize part of the ferrous ions present in the chromium removal liquid to form ferric ions, and further a pH adjuster Is added to the ferric hydroxide to adjust the pH to perform ferrous hydroxide neutralization treatment to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed, and an oxidizing agent is added to the dispersion treatment liquid to oxidize it. The dispersion treatment is performed while maintaining the reduction potential at 600 mV or higher. 1B iron neutralization treatment in which the remaining ferrous ions in the mixture are oxidized to ferric ions, and then the pH is adjusted to ferric hydroxide by adding a pH adjuster to the dispersion treatment liquid. To produce ferric hydroxide starch, and to separate the ferric hydroxide starch into a third treatment solution containing nickel and zinc, and to perform step 3A. To recycle waste plating sludge. 23. The recycling method for multicomponent plating waste liquid sludge according to claim 22, wherein the 1B iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. In the recycling method of the multi-component plating waste liquid sludge according to any one of claims 14 to 19, the pH is adjusted by adding a pH adjuster to the second treatment liquid instead of the third step. Then, a chromium neutralization treatment is performed by changing chromium ions in the second treatment liquid to chromium hydroxide to produce a chromium hydroxide starch, and the chromium hydroxide starch is separated to form a chromium removal liquid. An oxidizing agent is added to the removal solution to maintain the oxidation-reduction potential at 600 mV or more to oxidize ferrous ions in the chromium removal solution to ferric ions, and then a pH adjuster is added to adjust the pH. The ferrous hydroxide starch is produced by carrying out the 1C iron neutralization treatment for converting to ferric hydroxide, and the ferric hydroxide starch is separated and the third treatment containing nickel and zinc. A multi-component system characterized by performing step 3B as a liquid Recycling processing method can waste sludge. 25. The recycling method for multi-component plating waste liquid sludge according to claim 24, wherein the 1C iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. Sludge dissolution treatment is performed by adding an inorganic acid to a multi-component plating waste liquid sludge containing nickel, copper, zinc, iron, chromium, and organic matter to dissolve the multi-component plating waste liquid sludge to form a dissolved processed product. A first step of providing an insoluble matter removal treatment for removing the insoluble matter from the dissolved treatment product to obtain a first treatment liquid in which a part of nickel, copper, zinc, iron, chromium, and organic matter is mixed;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step of forming a second treatment liquid containing zinc, iron, chromium, and organic matter;
The iron powder is added to the second treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the second treatment liquid are replaced with iron, and the nickel-adhered iron powder on which nickel is deposited is separated, and zinc is separated. , A third step as a third treatment liquid containing iron, chromium, and organic matter,
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjusting agent to the third treatment solution to adjust the pH, and performing a chromium neutralization treatment in which chromium ions in the third treatment solution are changed to chromium hydroxide. And an oxidizing agent is added to the chromium hydroxide dispersion treatment solution to decompose organic substances present in the chromium hydroxide dispersion treatment solution and oxidize ferrous ions in the chromium hydroxide dispersion treatment solution. Then, a ferric hydroxide starch is formed by carrying out an iron neutralization treatment by adjusting the pH by adding a pH adjusting agent to convert the ferric ion to ferric hydroxide. A fourth step of separating ferric oxide starch together with the chromium hydroxide to form a fourth treatment liquid containing zinc;
Zinc neutralization treatment is performed by adjusting the pH of the fourth treatment liquid and changing zinc ions in the fourth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And having a fifth step as a fifth treatment liquid from which zinc has been removed,
An organic material is decomposed from the multi-component plating waste liquid sludge to separate and recover nickel, copper, zinc, iron, and chromium, and a method for recycling multi-component plating waste sludge. 27. The recycling method for multi-component plating waste liquid sludge according to claim 26, wherein the iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. Recycling method of multi-component plating waste liquid sludge. The recycling method for multi-component plating waste liquid sludge according to any one of claims 26 and 27, wherein ferrous iron is added together with an oxidizing agent to the chromium hydroxide dispersion treatment liquid. Recycling method of component plating waste liquid sludge. 29. The recycling method for multi-component plating waste liquid sludge according to any one of claims 26 to 28, wherein an oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide. Recycling method of component plating waste liquid sludge. 27. In the recycling method for multi-component plating waste liquid sludge according to claim 26, instead of the fourth step, a pH adjusting agent is added to the third treatment liquid to adjust the pH, and the third treatment liquid contains Chromium neutralization treatment is carried out by changing chromium ions into chromium hydroxide to produce a chromium hydroxide starch. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. An oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to decompose organic substances present in the chromium removing solution and to oxidize a part of ferrous ions present in the chromium removing solution to form ferric ions. Further, a first iron neutralization treatment is performed by adding a pH adjusting agent to adjust the pH to ferric hydroxide to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed, and the dispersion treatment liquid is oxidized. To the redox potential of 600 mV The organic substances present in the dispersion treatment liquid are decomposed while being held on the top, and the remaining ferrous ions in the dispersion treatment liquid are oxidized to ferric ions, and then a pH adjuster is added to the dispersion treatment liquid. In addition, a second iron neutralization treatment is performed to adjust the pH to ferric hydroxide to produce ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc A method of recycling a multi-component plating waste liquid sludge, comprising performing the step 4A as a fourth treatment liquid. 31. The recycling method for multi-component plating waste liquid sludge according to claim 30, wherein the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. 27. In the recycling method for multi-component plating waste liquid sludge according to claim 26, instead of the fourth step, a pH adjusting agent is added to the third treatment liquid to adjust the pH, and the third treatment liquid contains Chromium neutralization treatment is carried out by changing chromium ions into chromium hydroxide to produce a chromium hydroxide starch. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. An oxidation-reduction potential is maintained at 600 mV or more to decompose organic substances present in the chromium removal solution, ferrous ions in the chromium removal solution are oxidized to ferric ions, and then a pH adjuster is added. A third iron neutralization treatment is performed to adjust the pH to ferric hydroxide to produce a ferric hydroxide starch, and the ferric hydroxide starch is separated to contain zinc. 4B process which makes 4 process liquid is performed, It is characterized by the above-mentioned Recycling processing method for component plating waste sludge. 33. The recycling method for multicomponent plating waste liquid sludge according to claim 32, wherein the third iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. Sludge dissolution treatment is performed by adding an inorganic acid to a multicomponent plating waste liquid sludge containing nickel, copper, zinc, iron, and chromium to dissolve the multicomponent plating waste liquid sludge to form a dissolution treatment product, and the dissolution treatment A first step of providing an insoluble content removal treatment for removing the insoluble content from the product to obtain a first treatment liquid mixed with nickel, copper, zinc, iron, and chromium;
Add iron powder to the first treatment liquid and adjust the oxidation-reduction potential and pH, replace the copper ions and iron in the first treatment liquid and separate the copper-attached iron powder on which copper is deposited, A second step as a second treatment liquid containing zinc, iron, and chromium;
The iron powder is added to the second treatment liquid and the oxidation-reduction potential and pH are adjusted, the nickel ions in the second treatment liquid are replaced with iron, and the nickel-adhered iron powder on which nickel is deposited is separated, and zinc is separated. A third step as a third treatment liquid containing iron, chromium, and
A chromium hydroxide dispersion treatment in which chromium hydroxide is dispersed by adding a pH adjusting agent to the third treatment solution to adjust the pH, and performing a chromium neutralization treatment in which chromium ions in the third treatment solution are changed to chromium hydroxide. And oxidize the chromium hydroxide dispersion treatment solution to oxidize ferrous ions in the chromium hydroxide dispersion treatment solution to ferric ions, and then adjust the pH by adding a pH adjuster. Then, ferric hydroxide starch is produced by performing iron neutralization treatment to convert ferric ions to ferric hydroxide, and the ferric hydroxide starch is separated together with the chromium hydroxide to form zinc. A fourth step as a fourth treatment liquid containing
Zinc neutralization treatment is performed by adjusting the pH of the fourth treatment liquid and changing zinc ions in the fourth treatment liquid to zinc hydroxide to produce a zinc hydroxide starch, and the zinc hydroxide starch is separated. And having a fifth step as a fifth treatment liquid from which zinc has been removed,
A method for recycling a multicomponent plating waste liquid sludge, wherein nickel, copper, zinc, iron, and chromium are separated and recovered from the multicomponent plating waste liquid sludge. 35. The recycling method for multi-component plating waste liquid sludge according to claim 34, wherein the iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. Recycling method of multi-component plating waste liquid sludge. 36. The recycling method for multicomponent plating waste liquid sludge according to any one of claims 34 and 35, wherein the oxidizing agent added to the chromium hydroxide dispersion treatment liquid is hydrogen peroxide. Recycling method of component plating waste liquid sludge. 35. The recycling method for multi-component plating waste liquid sludge according to claim 34, wherein instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid contains Chromium neutralization treatment is carried out by changing chromium ions into chromium hydroxide to produce a chromium hydroxide starch. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. The oxidation-reduction potential is maintained at 400 mV or more and 500 mV or less to oxidize a part of ferrous ions present in the chromium removal solution to ferric ions, and further adjust the pH by adding a pH adjuster. The first iron neutralization treatment to be converted to ferric hydroxide is performed to obtain a dispersion treatment liquid in which ferric hydroxide is dispersed, and an oxidizing agent is added to the dispersion treatment liquid to maintain the oxidation-reduction potential at 600 mV or more. The remainder of the ferrous ion in the dispersion treatment liquid Oxidized to ferric ions, and then a second iron neutralization treatment was performed by adding a pH adjuster to the dispersion treatment liquid to adjust the pH to ferric hydroxide, thereby converting to ferric hydroxide starch. And a step 4A of separating the ferric hydroxide starch into a fourth treatment solution containing zinc, and performing a recycling process for the multicomponent plating waste liquid sludge. 38. The recycling method of multi-component plating waste liquid sludge according to claim 37, wherein the second iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. 35. The recycling method for multi-component plating waste liquid sludge according to claim 34, wherein instead of the fourth step, a pH adjuster is added to the third treatment liquid to adjust the pH, and the third treatment liquid contains Chromium neutralization treatment is carried out by changing chromium ions into chromium hydroxide to produce a chromium hydroxide starch. The chromium hydroxide starch is separated into a chromium removal solution, and an oxidizing agent is added to the chromium removal solution. Maintaining the oxidation-reduction potential at 600 mV or more, ferrous ions in the chromium removal solution are oxidized to ferric ions, and then a pH adjuster is added to adjust the pH to change to ferric hydroxide. Performing a third iron neutralization treatment to produce ferric hydroxide starch, separating the ferric hydroxide starch, and performing step 4B as a fourth treatment liquid containing zinc. A recycling method for multi-component plating waste liquid sludge that is characterized. 40. The recycling method for multi-component plating waste liquid sludge according to claim 39, wherein the third iron neutralization treatment is performed at 60 ° C. or higher, preferably 75 ° C. or higher, less than 100 ° C., preferably 85 ° C. or lower. A recycling method for multi-component plating waste sludge characterized by the above. 41. The recycling method for multi-component plating waste liquid sludge according to claim 1, wherein the pH adjuster is a weak alkali agent. Recycling method. The recycling method for multi-component plating waste liquid sludge according to any one of claims 1 to 41, wherein in the first step, hydrochloric acid is used as the inorganic acid, and the sludge dissolution treatment is performed by adjusting the pH. A recycling method for multi-component plating waste liquid sludge, which is performed under conditions of 0.5 to 2 and a temperature of 80 ° C. to less than 100 ° C. The recycling method of the multicomponent plating waste liquid sludge according to claim 42, wherein between the sludge dissolution treatment and the insoluble matter removal treatment, sulfuric acid is added to the dissolution treatment product, and a calcium source is further added to adjust the pH. A recycling method for multi-component plating waste liquid sludge, wherein gypsum is produced by setting the temperature to 1 to 2 and the temperature to 80 ° C. to less than 100 ° C. In the recycling method of the multicomponent plating waste liquid sludge according to any one of claims 1 to 41, sulfuric acid is used as the inorganic acid in the first step, and the sludge dissolution treatment is performed at a pH of 0.5 to 2 and the temperature is 80 ° C. to less than 100 ° C., and between the sludge dissolution treatment and the insoluble matter removal treatment, a calcium source is added to the dissolution treatment product to adjust the pH to 1. Recycling of multi-component plating waste liquid sludge characterized by providing a sulfate radical removal treatment in which the temperature is 80 ° C. or higher and lower than 100 ° C. and the sulfate radical in the dissolved treatment product is removed as gypsum. Processing method.

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