JP5041700B2 - Method for producing material with phosphate coating - Google Patents

Description

  The present invention relates to a method for producing a material with a phosphate coating used for coating base and plastic working.

  Conventionally, phosphate treatment has been performed on various materials for the purpose of improving performance such as corrosion resistance and paint adhesion and improving lubricity during plastic working. In general, after the phosphating, water is washed for the purpose of washing away the phosphating solution excessively adhering to the material to be treated. On the other hand, there are a spray method in which flush water is sprayed, a dip method in which the entire material to be treated is immersed in a bath filled with flush water, and the like.

  The performance of the material to be treated after the phosphate treatment varies greatly depending on whether the washing with water is good or bad. For example, if the excess phosphate treatment solution is removed by washing with higher purity water, better performance can be obtained. In particular, the body of automobiles and the surface of household electrical appliances affect the value of products, and the cleaning of materials to be treated is regarded as important.

When such washing is performed, new flush water is usually replenished at all times. For example, in the case of the dip method in which two or more bathtubs, which is a preferred embodiment, are provided, new flush water is constantly supplied to the downstream bathtub (tub for final cleaning). The flush water is then sent to the upstream tub and reused.
And finally, it is discharged from the most upstream bathtub as washing waste water outside the washing process system. This washing waste water contains a phosphating solution adhering to the material to be treated.

An example of such a dip cleaning method will be described with reference to FIG.
FIG. 2 is a schematic diagram of a line in which a material to be treated such as an automobile body is subjected to phosphate treatment and cleaned by a dip method. In the line shown in FIG. 2, the material to be treated 50 is immersed in the phosphating tank 1 to form a phosphate film. And the phosphate chemical conversion liquid adhering excessively to the to-be-processed material 50 is washed away in the 1st water washing tank 2, the 2nd water washing tank 3, and the 3rd water washing tank 4 one by one.
Flushing water (supplementary flushing water 5) is supplied to the third flushing tank 4 in order to perform good washing, and then used in the second flushing tank 3 through the third flushing overflow pipe 6, and further to the second flushing water. It passes through the overflow pipe 7 and is used in the first water washing tank 2, and finally passes through the first water washing overflow pipe 8 and is discharged as washing waste water 52. The replenishing flush water 5 is replenished on the downstream side in the conveying direction of the material to be treated 50 and is sequentially supplied and used on the upstream side, but the washing drainage 52 having the same amount as the replenishing flush water 5 replenished on the downstream side is provided. It is discharged through the first flush overflow pipe 8.

The washing waste water 52 contains a component in the phosphate chemical conversion treatment liquid (hereinafter also referred to as “phosphate chemical conversion treatment component”) and cannot be discharged as it is. Therefore, this is usually treated by wastewater treatment equipment, etc., and the wastewater is cleared to meet the wastewater standard value. In this wastewater treatment facility or the like, generally, a phosphate conversion component is insolubilized and separated by neutralization and coagulation precipitation, and then a separation liquid (supernatant liquid or the like) is discharged.
Most of the insolubilized phosphate chemical conversion components are currently treated as waste. Therefore, effective utilization of this phosphate chemical conversion component is desired.

Examples of conventional methods related to this include the methods described in Patent Documents 1 to 3 shown below.
In Patent Document 1, in the phosphate film conversion treatment of iron and steel, a multi-stage water washing step is provided after the film formation step, and a part of the washing water is reverse osmotic pressure with a reverse osmosis membrane having 1 to 10 A holes. A method is described in which the concentrated water is treated and returned to the film formation step, while the permeate is subjected to ion exchange treatment and then used as makeup water for the film formation and / or degreasing water washing step.
And according to this method, almost no wastewater treatment is required as in the conventional method, the washing water is subjected to reverse osmotic pressure treatment, and components useful for film formation in the washing water are concentrated and recovered, and reused for film formation. Membrane permeated water containing unnecessary components can be passed through ion exchange treatment to remove miscellaneous ions and reused as makeup water for final degreasing and / or film formation. It is described that it can be kept in a stable phosphating solution.

Patent Document 2 discloses a step of adjusting pH by adding alkali to washing water after nickel plating, and converting nickel ions in the washing water into nickel hydroxide or a mixture of nickel hydroxide and nickel carbonate, and generated hydroxylation. It comprises a step of separating nickel or a mixture of nickel hydroxide and nickel carbonate from washing water, and a step of dissolving and recovering the separated nickel hydroxide or a mixture of nickel hydroxide and nickel carbonate with a nickel plating solution. A nickel recovery method in the nickel plating step is described.
In this method, nickel in the washing water is separated as nickel hydroxide or a mixture of nickel hydroxide and nickel carbonate, and this is dissolved and recovered by the plating solution, so other components are brought into the nickel plating solution. It is described that there is an advantage that impurities are not accumulated and the plating solution is not broken, and there is an advantage that the washing water containing nickel does not need to be drained and discarded.

Furthermore, in Patent Document 3, pulse plating of the secondary molded product is performed in a plating tank containing a sulfuric acid plating bath, and the secondary molded product subjected to the pulse plating is washed in multiple stages. The washing water is sequentially sent to the upstream stage and finally supplied to the plating tank, and the washing water supplied to the plating bath is recovered by evaporating the plating bath in the plating tank. An electrogalvanizing method for secondary molded products is described.
And it is described that 100% recycling / closing of washing water and waste water can be realized by recovering the washing water for the amount evaporated in the plating bath.
Japanese Patent Publication No.59-10430 JP 2005-29874 A Japanese Patent Laid-Open No. 11-071696

  However, in the method described in Patent Document 1, it is necessary to use a large amount of membranes for separating and concentrating the phosphate chemical conversion component from a large amount of washing wastewater, which increases the equipment cost.

  In addition, when using a phosphating solution instead of the nickel plating solution used in the method described in Patent Document 2, the amount of phosphoric acid is larger than the metal component contained, so that metal ions and precipitates are used. Phosphoric acid that does not produce sucrose cannot be solidified even after neutralization and cannot be recovered. Therefore, with this method, it is difficult to efficiently recover phosphoric acid as a main component.

  Furthermore, in the method described in Patent Document 3, in the case of a line that uses a large amount of washing water, such as an automobile body line, a plating bath for the washing water to be used (phosphate treatment solution when applied to phosphate treatment). Since the evaporation amount of water is very small, 100% of the washing waste water cannot be recovered. Therefore, the merit to apply cannot be obtained.

  As described above, the conventional method has several problems. Accordingly, an object of the present invention is to provide a method for producing a material with a phosphate coating that solves these problems, and a method for recovering a phosphate chemical conversion treatment component, that is, phosphoric acid containing phosphate ions in washing waste water. The object is to provide a method for producing a material with a phosphate coating, which can efficiently separate and recover the chlorination treatment component and has low equipment costs and low running costs, and a method for recovering the phosphate conversion treatment component. .

The present inventor has intensively studied and found that the following (1) to ( 12 ) are means for solving the above problems.
(1) A phosphate chemical conversion treatment process in which a phosphate chemical conversion treatment component is obtained by bringing a treatment liquid containing a phosphate chemical conversion treatment component into contact with a material to be treated to obtain a phosphate coating material; A washing step of washing the treated material with washing water, a chemical addition step of adding a metal component and an alkali component to the washing waste water discharged in the washing step, and adding the metal component and the alkali component With a phosphate coating comprising a separation step of separating solids from the washing waste water, and a reuse step of using the separated solids as the phosphate chemical treatment component in the phosphate chemical treatment step A method of manufacturing a material ,
The metal component is selected from the group consisting of zinc nitrate, nickel nitrate, manganese nitrate, magnesium nitrate, zinc nitrite, zinc carbonate, nickel carbonate, manganese carbonate, magnesium carbonate, zinc oxide, nickel oxide, manganese oxide, and magnesium oxide. And
A method for producing a material with a phosphate coating, wherein the alkaline component is selected from the group consisting of sodium hydroxide, ammonia, and potassium hydroxide.
(2) In the recycling step, the separated solid content is added directly to the treatment liquid used in the phosphate chemical conversion treatment step or after being mixed with water, thereby adding the phosphatization. The method for producing a material with a phosphate film according to the above (1), which is used as a composition treatment component.
(3) In the recycling step, an acidic liquid is added to the separated solid to form a mixed solution, and the mixed solution is added to the treatment solution used in the phosphate chemical conversion treatment step, thereby the phosphate chemical conversion. The manufacturing method of the material with a phosphate film as described in said (1) utilized as a process component.
(4) A part of the treatment liquid used in water and / or the phosphate chemical conversion treatment step is added to the separated solid content, and the acidic liquid is further added to form a mixed solution. Of manufacturing a material with a phosphate coating.
(5) In the said reuse process, the manufacturing method of the material with a phosphate membrane | film | coat as described in said (3) or (4) whose pH of the said liquid mixture is 1-3.
(6) In the said chemical | medical agent addition process, after adding the said metal component to the said washing waste_water | drain, manufacture of the material with a phosphate membrane | film | coat in any one of said (1)-(5) which adds the said alkali component. Method.
(7) The method for producing a material with a phosphate film according to any one of (1) to (5), wherein in the chemical addition step, the metal component and the alkali component are simultaneously added to the washing waste water.
(8) The manufacturing method of the material with a phosphate film in any one of said (1)-(7) which satisfy | fills following formula (i).
Formula (i): 0.6 ≦ (B + C) × 2 / (A × 3) ≦ 1.5
A: Molar concentration (mol / L) of phosphate ion in the washing wastewater discharged in the washing step
B: Total molar concentration (mol / L) of metal ions in the washing wastewater discharged in the washing step
C: Total molar concentration conversion value (mol / L) of the addition amount of the metal component to the washing wastewater in the chemical addition step
(9) In the chemical addition step, the metal component and the alkali component are added to the washing waste water so that the pH of the washing waste water to which both the metal component and the alkali component are added is 7 to 11. The manufacturing method of the material with a phosphate film in any one of said (1)-(8).
(10) In the separation step, the solid content is separated from the washing waste water by at least one separation method selected from the group consisting of a sedimentation separation method, a pressure flotation separation method, a centrifugal separation method, and a membrane filtration separation method. The manufacturing method of the material with a phosphate membrane | film | coat in any one of said (1)-(9).
(11) The separation liquid is further separated in the separation step, and the separation liquid is used as washing water in the washing step and / or washing water after degreasing treatment performed before the phosphate chemical conversion treatment step. The method for producing a material with a phosphate coating according to any one of (1) to (10), further comprising a water recycling step.
(12) A method of recovering a phosphate chemical conversion component from a washing waste water after a phosphate chemical conversion treatment, a cleaning step of cleaning a material to be processed with a phosphate chemical conversion treatment with washing water, and the cleaning step The solid component is separated and recovered as a phosphate chemical treatment component from the chemical addition step of adding metal components and alkali components to the cleaning wastewater discharged in step 1, and the cleaning wastewater to which the metal components and alkali components are added. A method of recovering a phosphate chemical conversion treatment component comprising a separation step ,
The metal component is selected from the group consisting of zinc nitrate, nickel nitrate, manganese nitrate, magnesium nitrate, zinc nitrite, zinc carbonate, nickel carbonate, manganese carbonate, magnesium carbonate, zinc oxide, nickel oxide, manganese oxide, and magnesium oxide. And
A method for recovering a phosphate chemical conversion treatment component, wherein the alkali component is selected from the group consisting of sodium hydroxide, ammonia, and potassium hydroxide.

ADVANTAGE OF THE INVENTION According to this invention, the phosphate chemical conversion process component containing the phosphate ion in washing | cleaning waste_water | drain can be isolate | separated and collect | recovered efficiently.
In addition, in order to realize the present invention, since only simple equipment such as a solid-liquid separation device, a chemical addition tank and a pH adjustment tank are installed, the equipment cost can be suppressed, and there is no complicated management at the time of operation. Is also cheap.

  Further, the present invention further separates the separated liquid in the separation step, and the separated liquid is washed with water in the washing step and / or washed water after degreasing performed before the phosphate chemical conversion treatment step. As a result, it is possible to further include a water recycling step that is used as a waste water, and thereby it is possible to collect almost the entire amount of the washing waste water.

A first aspect of the present invention is a phosphate chemical conversion treatment step in which a treatment liquid containing a phosphate chemical conversion treatment component is brought into contact with a material to be treated to perform a phosphate chemical conversion treatment to obtain a phosphate coating material. A washing step of washing the material to be treated that has undergone the phosphate conversion treatment with washing water, a chemical addition step of adding a metal component and an alkali component to the washing waste water discharged in the washing step, the metal component and the metal A separation step of separating a solid content from the washing wastewater to which an alkali component is added; and a reuse step of using the separated solid content as the phosphate chemical conversion treatment component in the phosphate chemical conversion treatment step. It is a manufacturing method of the material with a phosphate film.
Hereinafter, such a production method is also referred to as a “production method of the present invention”.

Moreover, the second aspect of the present invention is a method for recovering a phosphate chemical conversion treatment component from the washing waste water after the phosphate chemical conversion treatment, wherein the material to be treated which has been subjected to the phosphate chemical conversion treatment is washed with washing water. From the washing step, the chemical addition step of adding a metal component and an alkali component to the washing wastewater discharged in the washing step, and the washing wastewater to which the metal component and the alkali component are added, as a phosphate chemical conversion treatment component And a separation step of separating and recovering a solid content.
Hereinafter, such a method for recovering the phosphate chemical conversion component is also referred to as “the recovery method of the present invention”.
In addition, the simple description of “the present invention” means both the production method of the present invention and the recovery method of the present invention.

The first aspect of the present invention (the production method of the present invention) and the second aspect (the recovery method of the present invention) are different from the first aspect that includes a phosphate chemical conversion treatment step and a reuse step. The second embodiment is different in that it does not include these steps.
Since the first aspect and the second aspect of the present invention differ only in these points, the manufacturing method of the present invention which is the first aspect of the present invention will be described below.

The manufacturing method of this invention is demonstrated using FIG.
FIG. 1 is a schematic diagram showing a preferred embodiment of the manufacturing method of the present invention.

<Phosphate chemical conversion treatment process>
In the production method of the present invention, the phosphate chemical conversion treatment step is performed by bringing a treatment liquid containing a phosphate chemical conversion treatment component (hereinafter also referred to as “chemical conversion treatment liquid”) into contact with the material to be treated. And a step of obtaining a material with a phosphate coating.

  Here, the material to be treated is not particularly limited, and any material can be used as long as it can form a phosphate film on the surface thereof by, for example, contacting a chemical conversion treatment solution described below by a conventionally known method. . A material having a metal on at least a part of its surface is preferable. Specific examples include electrical products such as cold rolled steel sheets and galvanized steel sheets, or aluminum-based materials, automobile bodies, automobile parts, and the like.

  Further, as the chemical conversion treatment liquid, known treatment liquids such as zinc phosphate-based and zinc calcium phosphate-based can be used. Among these, zinc phosphate-based chemical conversion treatment liquids are preferably used when applied to materials to be treated such as automobile bodies, building materials, and electrical parts because they form a film having good corrosion resistance and coating adhesion. This zinc phosphate-based chemical conversion treatment liquid contains phosphoric acid and zinc as main components, and may contain heavy metals such as nickel and manganese, fluorine, nitric acid and the like as subcomponents. Furthermore, you may contain the oxidizing agent used as promoters, such as nitrous acid.

In the phosphate chemical conversion treatment step of the production method of the present invention, there is no particular limitation on the method of phosphate chemical conversion treatment by bringing such chemical conversion treatment liquid into contact with the material to be treated. For example, a conventionally known method is applied. can do.
In the preferred embodiment shown in FIG. 1, the chemical conversion treatment tank 9 performs the phosphate chemical conversion treatment by immersing the material 50 to be treated, which is conveyed by the conveying means, in the chemical conversion liquid.
As another method for bringing the chemical conversion treatment solution into contact with the material to be treated and performing the phosphate chemical conversion treatment, a method of spraying the chemical conversion treatment solution onto the material to be treated with a shower nozzle or the like can be cited.

<Washing process>
In the production method of the present invention, the washing step is a step of washing the material to be treated which has undergone the phosphate conversion treatment with washing water.

In the cleaning step of the production method of the present invention, a method for performing such cleaning is not particularly limited, and for example, a conventionally known method can be applied.
The washing process in the preferred embodiment shown in FIG. 1 has three washing tanks: a first washing tank 10, a second washing tank 11, and a third washing tank 12. In this preferred embodiment, the material to be treated 50 that has been subjected to the phosphate chemical treatment in the phosphate chemical treatment step is first immersed in the first water rinsing tank 10 and washed. Then, the second water washing tank 11 and the third water washing tank 12 are dipped in this order and continuously washed.
As another cleaning method that can be applied in the cleaning step of the production method of the present invention, for example, a method of spraying water to be treated with a shower nozzle or the like can be mentioned.

  In the cleaning step in the preferred embodiment shown in FIG. 1, replenished flush water 17 is replenished to the third flush tank 12 as flush water. The flush water is supplied to the second flush tank 11 through the third flush overflow pipe 18, is further supplied to the first flush tank 10 through the second flush overflow pipe 19, and finally passes through the flush drainage liquid feeding pipe 20. Drained. In this way, the flush water is replenished on the downstream side in the conveying direction of the material to be treated 50 and is sequentially supplied and used on the upstream side.

In this way, the cleaning process is to wash away the chemical conversion treatment solution adhering excessively to the material to be treated. If these are not almost completely removed, the coating is performed on the phosphate film formed on the surface of the material to be treated. In such a case, the fixing state becomes unstable and the coating quality and the like are deteriorated. Therefore, it is preferable to wash with water a plurality of times (three times in the preferred embodiment) as in the preferred embodiment described above.
In addition, the manufacturing method of this invention may have the pure water washing process using a pure water as needed. In this case, it is usually added as a post-process of the third washing tank 12. This is preferable because the cleaning can be performed at a higher level.

<Drug addition process>
In the production method of the present invention, the chemical addition step is a step of adding a metal component and an alkali component to the cleaning wastewater discharged in the cleaning step.

Here, the metal component is added to the washing waste water discharged in the washing step, and when pH adjustment is performed as necessary, it reacts with phosphoric acid in the washing waste water to form a solid compound insoluble in water ( It is not particularly limited as long as it forms a solid content in the separation step described later. It may be a mixture of two or more metal components.
For example, zinc nitrate, nickel nitrate, manganese nitrate, copper nitrate, magnesium nitrate, calcium nitrate, cobalt nitrate, zinc nitrite, calcium nitrite, zinc carbonate, nickel carbonate, manganese carbonate, copper carbonate, magnesium carbonate, calcium carbonate, carbonate Cobalt, zinc oxide, nickel oxide, manganese oxide, copper oxide, magnesium oxide, calcium oxide, cobalt oxide, zinc sulfate, nickel sulfate, manganese sulfate, copper sulfate, magnesium sulfate, calcium sulfate, cobalt sulfate, zinc hydroxide, hydroxide Examples of the metal salt include nickel, manganese hydroxide, copper hydroxide, magnesium hydroxide, calcium hydroxide, and cobalt hydroxide. A mixture of two or more of these may be used. Such a metal component is preferably a component of the chemical conversion treatment solution used in the phosphate chemical conversion treatment step or a compound thereof (metal salt). For example, when a zinc phosphate-based chemical conversion treatment solution is used as the chemical conversion treatment solution in the phosphate chemical conversion treatment step, the metal component used here is preferably a zinc-based compound. Since zinc has a high rate of precipitation as a chemical conversion film, it can be added in a large amount. Therefore, phosphoric acid can be efficiently recovered while keeping the components of the chemical conversion treatment liquid substantially constant.

Further, in consideration of reactivity when added to the washing waste water, workability in addition of the metal component, and the like, it is preferable to add the metal component to the washing waste water in a dissolved state.
Moreover, you may add with powder. This powder preferably has a particle size of 2 mm or less. A powder having such a particle size is preferable because of high reactivity. However, it is possible to use even larger particle diameters.

The amount of the metal component added is preferably determined by the following method.
First, an electrical conductivity meter is installed in the first washing tank 10 or the washing drainage liquid feeding pipe 20, and the electrical conductivity of the washing drainage sent to the metal component addition tank 13 is measured. Then, the relationship between the measured value of the electrical conductivity and the molar concentration (mol / L) of phosphate ions and the molar concentration of metal ions (mol / L) in the cleaning wastewater discharged in the cleaning step is obtained in advance. Keep it. This relationship is generally a directly proportional relationship.
Then, at the time of operation, the electrical conductivity is measured to determine the molar concentration (mol / L) of the phosphate ion and the molar concentration (mol / L) of the metal ion.
Further, as another method, the cleaning waste water may be sampled and chemically analyzed to obtain the molar concentration thereof.

Next, the obtained molar concentration of phosphate ion and the molar concentration of metal ion are applied to (A) and (B) of the following formula (i), and the addition amount (C) of the metal component satisfying this formula (i) Ask for.
Formula (i): 0.6 ≦ (B + C) × 2 / (A × 3) ≦ 1.5
A: Molar concentration (mol / L) of phosphate ion in the washing wastewater discharged in the washing step
B: Total molar concentration (mol / L) of metal ions in the washing wastewater discharged in the washing step
C: Total molar concentration conversion value (mol / L) of the addition amount of the metal component to the washing wastewater in the chemical addition step

  It is preferable that the added amount of the metal component satisfying the formula (i) (C (mol / L)) since phosphate ions can be efficiently recovered. It is preferable that the value of (B + C) × 2 / (A × 3) in the formula (i) is 0.6 or more because the phosphate ion recovery efficiency is increased. Moreover, it is preferable that it is 1.5 or less because the amount of the solid content separated in the later-described separation step and not derived from phosphate ions or metal ions in the washing waste water does not increase. For example, when the solid content separated in the separation step described later is reused, the amount of the acidic liquid used is unnecessarily large when the solid content is reused after being dissolved by adding the acidic liquid. This is preferable. Further, for example, in the chemical addition step, when the pH of the washing waste water is adjusted to a preferable range, the amount of the alkaline component to be used is not unnecessarily increased, which is preferable.

  Moreover, in this chemical | medical agent addition process, an alkaline component will not be specifically limited if it has the effect | action which raises the pH of this washing wastewater, when it adds to the said washing wastewater. For example, sodium hydroxide, calcium hydroxide, ammonia, potassium hydroxide and the like, and aqueous solutions in which these are dissolved can be mentioned. Among these, it is preferable that they are the sodium hydroxide aqueous solution which is the aqueous solution containing the component contained in the said chemical conversion liquid, and ammonia water.

Further, in consideration of reactivity when added to the washing waste water, workability in the addition, etc., it is preferable to add the alkali component to the washing waste water in a state dissolved in a liquid.
Moreover, you may add with powder. This powder preferably has a particle size of 2 mm or less. A powder having such a particle size is preferable because of high reactivity. However, it is possible to use even particle sizes larger than this.

  Moreover, the addition amount of an alkali component should just be the quantity used as the pH which the solid content mentioned later in the said washing waste_water | drain produces | generates. The preferred pH is 7-11, more preferably 8-10. A pH in such a range is preferable because almost all of the phosphate chemical conversion component to be recovered, which will be described later, becomes a solid content and can be recovered more efficiently. Moreover, it is preferable that the pH is 11 or less because the amount of the alkali component does not increase so much that phosphoric acid and zinc are redissolved and the active ingredient cannot be efficiently recovered.

In the chemical addition process in the preferred embodiment shown in FIG. 1, the cleaning wastewater discharged in the cleaning process passes through the cleaning wastewater supply pipe 20 and is sent to the metal component addition tank 13. Then, the metal component is added from the metal component addition pipe 29 in the metal component addition tank 13.
The cleaning wastewater to which the metal component is added is supplied to the alkali component addition tank 14 through the metal component addition tank overflow pipe 21. And an alkali component is supplied from the alkali component addition piping 30 here.

  Moreover, in order to raise the reaction efficiency in the metal component addition tank 13 and the alkali component addition tank 14, it is preferable to stir in each tank. Furthermore, the reaction efficiency may be increased by adjusting the temperature and residence time. Moreover, you may add the powder etc. which become an aggregation nucleus when adding an alkali component to the alkali component addition tank 14.

In the chemical addition step of the manufacturing method of the present invention, the order in which the metal component and the alkali component are added to the cleaning wastewater is not limited, but as in the preferred embodiment shown here, When the alkali component is added after adding the metal component, the probability that the phosphate ion in the cleaning wastewater reacts with the added metal component to form a compound increases, and the phosphate ion in the cleaning wastewater is increased. Is preferable in that it can be separated and recovered more efficiently.
Further, when the metal component and the alkali component are simultaneously added to the washing waste water, for example, two tanks of the metal component addition tank 13 and the alkali component addition tank 14 as shown in FIG. 1 are combined into one tank. It is preferable because it can be operated. Moreover, it is preferable if the number of tanks can be reduced to one, because the equipment cost can be reduced. Here, “adding the metal component and the alkali component simultaneously” means, for example, adding a liquid containing the metal component and the alkali component, or a compound of the metal component and the alkali component. Is added.

  Further, when the washing wastewater contains two or more kinds of metal components and their precipitation pHs (pH to be precipitated as solids described later) are different, addition of alkali components and separation described later are performed in two stages. May be.

<Separation process>
In the production method of the present invention, the separation step is a step of separating a solid content from the washing wastewater to which the metal component and the alkali component are added.
That is, in this separation step, by adding the metal component and the alkali component, the solid content precipitated as a water-insoluble compound, and the solid content suspended in the washing wastewater can be reduced by any method. Separate from cleaning wastewater.

  Here, the method for separating the solid content from the washing waste water is not particularly limited, and for example, a conventionally known method can be applied. The separation is preferably performed by at least one separation method selected from the group consisting of a sedimentation separation method, a pressure flotation separation method, a centrifugal separation method, and a membrane filtration separation method.

  Here, the solid content is mainly composed of a compound of phosphoric acid, zinc, nickel, manganese, copper, magnesium, calcium, cobalt and the like, which are the phosphate chemical conversion treatment components, and the added metal component. Specifically, zinc phosphate, nickel phosphate, manganese phosphate, copper phosphate, magnesium phosphate, calcium phosphate, cobalt phosphate, etc. are the main components. In addition, calcium fluoride, iron phosphate, etc. May contain. Further, it usually contains 50 to 95% by mass of water.

  In such a separation step, chemicals such as a flocculant and a filter aid may be added in order to increase the solid-liquid separation property.

Further, when the solid content is separated from the washing waste water, a liquid remains, but this liquid usually contains components such as Na and NO ₃ .
In this separation step, at least a part of the remaining liquid is separated as a separation liquid, and this separation liquid can be used as washing water in the washing step.
Moreover, in the manufacturing method of this invention, since these components are discharged | emitted out of the system, the problem which accumulate | stores in a chemical conversion liquid does not arise. On the other hand, in the conventional method (for example, the method described in Patent Document 1) in which components in washing wastewater are collected using a reverse osmosis membrane, components such as Na and NO ₃ accumulate in the chemical conversion liquid. Therefore, its chemical conversion gradually deteriorates as the processing amount increases.

Moreover, it is preferable to use this separation liquid as washing water in the washing step after the advanced treatment described later. Similarly, this separated liquid can be used as washing water after the degreasing treatment performed before the phosphate chemical conversion treatment step, and is preferably used after the advanced treatment described later. Furthermore, it is preferable to reuse this separated liquid in the pure water washing step after the advanced treatment described later.
That is, in the production method of the present invention, the separation liquid is further separated in the separation step, and the separation liquid is washed with water in the washing step and / or after the degreasing treatment performed before the phosphate chemical conversion treatment step. It is possible to further include a water recycling process that is used as washing water.
Here, the advanced treatment is a treatment for separating and removing components such as Na, NO ₃ , and F from the separation liquid. For example, a method of separating a conventionally known dissolved component and water, such as a reverse osmosis membrane, an ion exchange resin, and a treatment using distillation, can be used.

  In the separation step in the preferred embodiment shown in FIG. 1, the washing waste water after the addition of the metal component and the alkali component discharged from the chemical addition step passes through the alkali component addition tank overflow pipe 22 to form a solid-liquid separation. It is supplied to the device 15. And it isolate | separates into solid content and a separated liquid, a solid content is sent to the reuse process mentioned later, and a separated liquid is discharged | emitted from the solid-liquid separation tank overflow piping 23. FIG. And the separation liquid discharged | emitted here can be utilized as the washing water in the said washing | cleaning process.

<Reuse process>
In the production method of the present invention, the reuse step is a step of using the separated solid content as the phosphate chemical treatment component in the phosphate chemical treatment step.

  In the production method of the present invention, the solid content separated in the separation step contains the same components as the phosphate chemical conversion component of the chemical conversion treatment liquid used in the phosphate chemical conversion treatment step. It can be used as an acid chemical conversion treatment component.

In this reuse step, a method of using the separated solid content as the phosphate chemical conversion component is not particularly limited.
For example, the separated solid content can be directly added to the chemical conversion solution and reused.
Moreover, after mixing the said solid content with water, it can add to the said chemical conversion liquid, and can be reused.
Moreover, after mixing the said solid content with a part of said chemical conversion liquid, it can add to the said chemical conversion liquid and can be reused.
Moreover, after adding the said solid content to an acidic liquid as a liquid mixture, this liquid mixture can be added to the said chemical conversion liquid, and can be reused.
In addition, after the solid content is dispersed in water and added to the acidic liquid to form a mixed liquid, the mixed liquid can be added to the chemical conversion liquid and reused.
Further, after the solid content is dispersed in a part of the chemical conversion treatment liquid, it is added to the acidic liquid to form a mixed liquid, and then this mixed liquid can be added to the chemical conversion liquid and reused.
Here, the separation liquid separated in the separation step can be used as water to be mixed with the solid content or as water in the acidic liquid to be added.
In addition, the solid content can be stored after being separated in the separation step and reused later.

  Among these, an acidic liquid is added to the separated solid to form a mixed solution, and the mixed solution is added to the treatment liquid (the chemical conversion treatment liquid) used in the phosphate chemical conversion treatment step, thereby the phosphorus. It is preferable to utilize as an acid chemical conversion treatment component. Moreover, it is preferable that pH of the said liquid mixture is 1-3. If this pH is 1 or more, the amount of acidic liquid required is not excessive, which is preferable. Moreover, if this pH is 3 or less, since the said solid content can be melt | dissolved almost completely, the recycle efficiency of the said solid content increases more, and it is preferable. In addition, if this acidic liquid is an acidic liquid which melt | dissolves the said solid content, it will not be limited. For example, nitric acid, phosphoric acid, and hydrofluoric acid can be used.

  Further, in this way, when the solid content is dispersed and mixed in water, acidic liquid or the like and then added to the chemical conversion treatment liquid and reused, the amount added is the tank for chemical conversion treatment liquid (chemical conversion treatment liquid). Considering the rise in the liquid level of the treatment tank), the amount of natural evaporation of the chemical conversion liquid in the chemical conversion tank is almost the same. However, when the solid content is added to the chemical conversion treatment liquid as it is, the liquid is not supplied from outside the system, so that even if the amount of the chemical conversion liquid as the dispersion medium is increased, the liquid level of the chemical conversion tank does not rise. There is. Further, after the solid content is dispersed in a part of the chemical conversion treatment liquid and then added to the acidic liquid as a mixed liquid, the liquid level of the chemical conversion tank increases when this mixed liquid is added to the chemical conversion liquid and reused. Furthermore, the solid content is more preferable because almost all of the solid content is dissolved.

In the reuse process in the preferred embodiment shown in FIG. 1, the solid content discharged from the separation process is supplied to the acidic liquid tank 16 through the solid content feeding pipe 24. An acidic liquid is added to the acidic liquid tank 16 from an acidic liquid addition pipe 31. The acidic liquid is not particularly limited as long as it has an effect of lowering pH, but is preferably contained in the chemical conversion treatment liquid. In this preferred embodiment, the acidic liquid is nitric acid, phosphoric acid, or hydrofluoric acid. Further, in order to improve the reaction efficiency (dissolution efficiency) in the acidic liquid tank 16, stirring is performed in this preferred embodiment.
After the solid content is dissolved in the acidic liquid tank 16, it is added to the chemical conversion treatment tank 9 through the mixed liquid feeding pipe 25 and used in the method for manufacturing the material with a phosphate film.

  In the production method of the present invention, the solid content separated in the recycling step is added to the chemical conversion treatment liquid. In order to keep the effective component concentration of the chemical conversion treatment liquid constant, phosphoric acid, a metal component, Components of the chemical conversion treatment liquid such as F and Si are added.

  Such an embodiment of the present invention is considered to have stable solid-liquid separation capability even when the oil and suspended substances (SS component) are present in the washing waste water and the apparatus is operated for a long time. On the other hand, for example, when the method described in Patent Document 1 is applied to an actual line, it is necessary to remove the oil and SS contained in the washing waste water because they adversely affect the performance of the reverse osmosis membrane. There are disadvantages such as complicated management of the entire system and requiring labor for maintenance.

Further, in Patent Document 1, the increased amount in the phosphate treatment tank (film chemical conversion) supplied with concentrated water or the like obtained by concentrating the washing wastewater is discharged as water vapor into the atmosphere, so that the balance of the liquid amount is maintained. For example, when a low-temperature phosphating solution of about 40 ° C. or lower is used, the amount of evaporation is small. Less concentrated). However, if the concentration of the concentrated water is increased in order to reduce the amount of concentrated water generated here, the active ingredient may be precipitated. In this case, since the performance of the reverse osmosis membrane is lowered and it becomes difficult to concentrate the washing waste water, the concentration of the concentrated water does not increase and the amount thereof does not decrease. And the amount of concentrated water increases with respect to the evaporation amount, and almost all of the concentrated water cannot be recovered. Therefore, the active ingredient cannot be recovered efficiently.
In contrast, in the present invention, the active ingredient is solidified and then added directly to the chemical conversion treatment liquid, water and / or a part of the chemical conversion treatment liquid is added, and the acidic liquid is further added to form a mixed liquid. It can add to the said chemical conversion liquid. In this case, it is considered that the total amount of the solid matter can be recovered and the active ingredient can be recovered efficiently by making the amount of the mixed solution to be added below the evaporation amount of the chemical conversion treatment solution.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Example 1>
Using the process shown in FIG. 1, a phosphate chemical conversion treatment step, a washing step, a chemical addition step, and a separation step were performed to produce a phosphate-coated material. However, the reuse process was not performed. Moreover, the pretreatment process was performed before the phosphate chemical conversion treatment process.

First, in the pretreatment step, an alkaline degreasing treatment was performed on the SPC steel plate (70 × 150 mm).
The alkaline degreasing agent aqueous solution used in the alkaline degreasing treatment was prepared as follows.
Two chemicals, a fine cleaner E2081A and a fine cleaner E2081B (both manufactured by Nihon Parkerizing Co., Ltd.) were prepared. First, the fine cleaner E2081A (powder) was dissolved in tap water. Here, the concentration was 13 g / L. Next, the fine cleaner E2081B (liquid) was further added to the aqueous solution in which the fine cleaner E2081A was dissolved so as to have a concentration of 7 g / L, and sufficiently stirred. In this way, 5 L of an alkaline degreaser aqueous solution in which the fine cleaner E2081A and the fine cleaner E2081B were dissolved was obtained.
And after adjusting this alkaline degreaser aqueous solution to 42 degreeC, the alkaline degreasing process was performed by immersing a SPC steel plate here for 120 seconds, shaking suitably.

The SPC steel sheet after the alkali degreasing treatment by such a method was subjected to a water washing treatment after degreasing.
The post-degreasing water washing treatment was performed using a first water washing tank after degreasing and a second water washing tank after degreasing. All of these post-degreasing water washing tanks have a capacity of 1L. The tap water is degreased and then supplied to the second flushing tank, and then the tap water is degreased and then sent to the first flushing tank, and is drained from the first flushing tank after the degreasing. After this degreasing, the amount of tap water supplied to the second washing tank was 100 mL / hr.
In such post-degreasing water washing treatment, the SPC steel plate after the alkali degreasing treatment was first immersed in a first water washing tank for 30 seconds after degreasing. And after degreasing, it was immersed in the 2nd washing tank for 30 seconds, and the water washing process was performed after degreasing.

  And after that, the surface adjustment process was performed. Here, first, a surface conditioner (preparene X (registered trademark), manufactured by Nihon Parkerizing Co., Ltd.) was added to tap water so as to have a concentration of 3 g / L and stirred, and then an additive (AD-4777) was further added thereto. , Made by Nihon Parkerizing Co., Ltd.) to a concentration of 1.2 g / L, and 5 L was prepared by stirring and dissolving in the same manner. And it surface-treated by immersing here for 30 seconds, shaking suitably.

After performing such a pretreatment process, a phosphate chemical conversion treatment process was performed.
The main components of the phosphate chemical conversion treatment solution used here are Zn: 28 mmol / L, Ni: 17 mmol / L, and PO ₄ : 147 mmol / L. 5 L of such a phosphate chemical treatment solution was prepared and adjusted to 42 ° C. And the phosphate chemical conversion treatment was performed by immersing here for 120 seconds, shaking suitably. And the material with a phosphate film was obtained.
Here, when the phosphate chemical conversion treatment is performed on the SPC steel sheet, the concentration of the zinc phosphate treatment solution after the treatment changes. Therefore, various components were replenished to the zinc phosphate treatment solution so that the concentration was constant. Moreover, it always replenished so that a promoter density | concentration might also become fixed (4.5p). The accelerator used here is AC131 (registered trademark) (manufactured by Nippon Parkerizing Co., Ltd.).
This accelerator concentration was determined by adding 5 g of G205 (registered trademark) (manufactured by Nihon Parkerizing Co., Ltd.) after putting a 50 mL sample into an instrument similar to the Kuhne tube (common name: Saccharometer). The amount was measured, and the accelerator concentration was 1 p per 1 mL of generated gas.
Further, the consumption amount of zinc phosphate treatment liquid per SPC steel plate (attachment amount to the surface of the SPC steel plate) was 1.5 mL / sheet.

A washing step was performed after such a phosphate chemical conversion treatment step. The washing process was performed using the first, second, and third water washing tanks as shown in FIG. These washing tanks all have a capacity of 1L. And after supplying ion-exchange water to a 3rd water-washing tank and carrying out the preceding stage to a 2nd water-washing tank and a 1st water-washing tank, it is discharged | emitted from a 1st water-washing tank as washing | cleaning waste water. The ion exchange water supply amount was 199.5 mL / hr.
In such a cleaning step, the SPC steel plate after being treated in the phosphate chemical conversion treatment step was first immersed in a first water washing tank for 30 seconds. And it wash | cleaned by immersing for 30 second each similarly in a 2nd water washing tank and a 3rd water washing tank after that.

Such a pretreatment process, a phosphate chemical conversion treatment process, and a cleaning process were performed at 7 sheets / hr (the number of processed SPC steel sheets per hour).
Then, the above pretreatment step, phosphate chemical conversion treatment step, and washing step were performed until the concentration of phosphate ions, zinc ions, and nickel ions in the washing wastewater discharged in this washing step became stable. .
Table 1 shows the amounts of phosphoric acid, zinc, and nickel added to the zinc phosphate treatment solution when the concentration of phosphate ions, zinc ions, and nickel ions in the washing wastewater becomes stable. The component concentration and discharge amount of the waste water are shown in Table 2.

As described above, the chemical addition step was performed using 1 L of the cleaning wastewater discharged in the cleaning step when the concentration of phosphate ions, zinc ions, and nickel ions in the cleaning wastewater became stable. .
In the chemical addition step, first, 4.1 g (Zn: 10.2 mmol / L) of 47 mass% Zn (NO ₃ ) ₂ solution was added to 1 L of washing waste water.
Next, 25 mass% NaOH was added to adjust the pH to 9.
After such operation, solid content was generated in the washing waste water.

After such a chemical addition step, a separation step was performed.
In the separation step, the washing waste water containing the solid content was subjected to a centrifugal separation process (5000 rpm, 5 minutes), and the solid content in the washing waste water containing the solid content was separated.
The volume ratio between the solid content and the remainder after separation was 1:19.

67.5 mass% HNO ₃ was added to the solid content separated by the method as described above to adjust to pH 2. The acidic liquid obtained by dissolving the solid content obtained here is hereinafter referred to as a mixed liquid.
The concentration of each component (PO ₄ , Zn, Ni) of this mixed solution was measured. And the recovery rate of each component was computed by following Formula (ii). These values are shown in Table 3.

  Formula (ii): recovery rate = (component amount in mixed solution−metal component addition amount) / (component amount in 1 L of washing wastewater−metal component addition amount) × 100

Here, the component amount in the mixed solution is a measured value (mmol / L) obtained by measuring each component (PO ₄ , Zn, Ni) in the mixed solution using ICP.
Also, ingredient amounts in detergent drain 1L is each component in the washing waste water discharged in the washing step _(PO 4, Zn, Ni) to the measured value measured using ICP (mmol / L).
The metal component addition amount is the Zn addition amount (10.2 mmol / L in Example 1) in the chemical addition step, and is calculated by substituting this value only when calculating the Zn recovery rate. . When calculating the recovery rate of PO ₄ and Ni, 0 is substituted for the metal component addition amount of the above formula (ii).

  In this case, phosphoric acid components and metal ions (mainly Zn ions and Ni ions) contained in the washing waste water, and further added metal components (Zn ions) are precipitated as solids as phosphoric acid compounds. And most metal ions can be recovered.

<Example 2>
In the chemical addition process of Example 1, except that 4.4 g of 47 mass% Zn (NO ₃ ) ₂ solution was added to 1 L of washing wastewater (Zn: 10.9 mmol / L), all were the same as Example 1, Processing operation of each process was performed. Table 4 shows the concentration and recovery rate of each component (PO ₄ , Zn, Ni) of the resulting mixed liquid.

  In the case of Example 2, as in Example 1, phosphoric acid and metal ions (Zn ions, Ni ions) can be almost recovered.

<Comparative Example 1>
Except not adding a metal component in the chemical | medical agent addition process of Example 1, all were made the same as Example 1, and the processing operation of each process was performed.
The recovery rate is a calculated value with the addition amount of the metal component in the above formula (ii) as 0.
The results are shown in Table 5.

  In this case, the metal component contained in the washing waste water was almost recovered, but the recovery rate of phosphoric acid as a main component was low.

FIG. 1 is a schematic diagram showing a preferred embodiment of the production method of the present invention. FIG. 2 is a schematic view of a line in which a material to be treated is treated with a phosphate and washed by a dip method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phosphate processing tank 2 1st water washing tank 3 2nd water washing tank 4 3rd water washing tank 5 Makeup water washing water 6 3rd water washing overflow piping 7 2nd water washing overflow piping 8 1st water washing overflow piping 9 Chemical conversion treatment tank 10 1st Washing tank 11 Second washing tank 12 Third washing tank 13 Metal component addition tank 14 Alkali component addition tank 15 Solid-liquid separator 16 Acid liquid tank 17 Replenished washing water 18 Third washing overflow pipe 19 Second washing overflow pipe 20 Washing drainage Liquid feed pipe 21 Metal component addition tank overflow pipe 22 Alkali component addition tank overflow pipe 23 Solid / liquid separation tank overflow pipe 24 Solid content liquid feed pipe 25 Mixed liquid feed pipe 26 Washing drainage liquid feed pump 27 Solid content liquid feed pump 28 Mixing Liquid feed pump 29 Metal component added piping 30 Alkaline component added piping 31 Acidic liquid Body-added piping 50 Material to be treated 52 Waste water for cleaning

Claims (12)

A phosphate chemical conversion treatment step in which a treatment liquid containing a phosphate chemical conversion treatment component is brought into contact with the material to be treated to perform a phosphate chemical conversion treatment to obtain a phosphate-coated material;
A washing step of washing the material to be treated which has undergone the phosphate conversion treatment with washing water;
A chemical addition step of adding a metal component and an alkaline component to the cleaning wastewater discharged in the cleaning step;
A separation step of separating a solid content from the washing wastewater to which the metal component and the alkali component are added;
A method for producing a material with a phosphate coating, comprising a recycling step of using the separated solid content as the phosphate chemical conversion treatment component in the phosphate chemical conversion treatment step ,
The metal component is selected from the group consisting of zinc nitrate, nickel nitrate, manganese nitrate, magnesium nitrate, zinc nitrite, zinc carbonate, nickel carbonate, manganese carbonate, magnesium carbonate, zinc oxide, nickel oxide, manganese oxide, and magnesium oxide. And
A method for producing a material with a phosphate coating, wherein the alkaline component is selected from the group consisting of sodium hydroxide, ammonia, and potassium hydroxide.   In the recycling step, the separated solid content is added directly to the treatment liquid used in the phosphate chemical treatment step or after being mixed with water, thereby adding the phosphate chemical treatment component. The manufacturing method of the material with a phosphate membrane | film | coat of Claim 1 utilized as these.   In the reuse step, an acidic liquid is added to the separated solid to form a mixed solution, and the mixed solution is added to the treatment solution used in the phosphate chemical conversion treatment step, thereby forming the phosphate chemical conversion treatment component. The manufacturing method of the material with a phosphate membrane | film | coat of Claim 1 utilized.   The phosphate according to claim 3, wherein water and / or a part of the treatment liquid used in the phosphate chemical conversion treatment step is added to the separated solid content, and the acidic liquid is further added to form a mixed solution. A method for producing a coated material.   The method for producing a material with a phosphate coating according to claim 3 or 4, wherein in the reuse step, the pH of the mixed solution is 1 to 3.   The method for producing a material with a phosphate coating according to any one of claims 1 to 5, wherein, in the chemical addition step, the alkali component is added after the metal component is added to the washing waste water.   The manufacturing method of the material with a phosphate film in any one of Claims 1-5 which adds the said metal component and the said alkali component to the said washing | cleaning waste_water | drain at the same time in the said chemical | medical agent addition process. The manufacturing method of the material with a phosphate membrane | film | coat in any one of Claims 1-7 which satisfy | fills following formula (i).
Formula (i): 0.6 ≦ (B + C) × 2 / (A × 3) ≦ 1.5
A: Molar concentration (mol / L) of phosphate ion in the washing wastewater discharged in the washing step
B: Total molar concentration (mol / L) of metal ions in the washing wastewater discharged in the washing step
C: Total molar concentration conversion value (mol / L) of the addition amount of the metal component to the washing wastewater in the chemical addition step In the said chemical | medical agent addition process, the said metal component and the said alkali component are added to the said washing | cleaning wastewater so that the pH of the said washing | cleaning wastewater to which both the said metal component and the said alkali component were added will be 7-11. The manufacturing method of the material with a phosphate membrane | film | coat in any one of -8.   In the separation step, the solid content is separated from the washing wastewater by at least one separation method selected from the group consisting of a sedimentation separation method, a pressurized flotation separation method, a centrifugal separation method, and a membrane filtration separation method. Item 10. A method for producing a material with a phosphate film according to any one of Items 1 to 9.   The separation liquid is further separated in the separation step, and the separation liquid is reused as water for washing in the washing step and / or water for washing after degreasing performed before the phosphate chemical conversion treatment step. The manufacturing method of the material with a phosphate film in any one of Claims 1-10 which further comprises a process. A method of recovering phosphate chemical treatment components from washing waste water after phosphate chemical treatment,
A washing step of washing the material to be treated that has undergone the phosphate conversion treatment with washing water;
A chemical addition step of adding a metal component and an alkaline component to the cleaning wastewater discharged in the cleaning step;
A method of recovering a phosphate chemical conversion treatment component comprising a separation step of separating and recovering a solid content as a phosphate chemical conversion treatment component from the washing wastewater to which the metal component and the alkali component are added ,
The metal component is selected from the group consisting of zinc nitrate, nickel nitrate, manganese nitrate, magnesium nitrate, zinc nitrite, zinc carbonate, nickel carbonate, manganese carbonate, magnesium carbonate, zinc oxide, nickel oxide, manganese oxide, and magnesium oxide. And
A method for recovering a phosphate chemical conversion treatment component, wherein the alkali component is selected from the group consisting of sodium hydroxide, ammonia, and potassium hydroxide.

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