JP2013075288A - Apparatus and method for metal recovery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for metal recovery, capable of directly performing solid-liquid separation of a crystal particle of a fine metal compound precipitated in water, without requiring a special reaction operation.SOLUTION: The metal recovery apparatus has: a precipitation tank 2 for precipitating the crystal particle of the metal compound from the water to be treated that contains a metal ion; a filter aid supply device 5 for supplying a filter aid having an average particle size of 0.5-20 μm in a free particle or aggregate containing a magnetic material; a mixing tank 6 for mixing the filter aid supplied from the filter aid supply device 5 with a dispersion medium; a solid-liquid separator 3 having a filter 33 for filtering a mixture supplied from the mixing tank 6 and for filtering the water to be treated that is supplied from the precipitation tank 2 to form a deposition layer of a metal compound crystal particle with the filter aid in the mixture; and a separation tank 4 for separating the metal compound crystal particle and the filter aid included in an exfoliated matter discharged from the solid-liquid separator 3 with the exfoliation water.

Description

  Embodiments described herein relate generally to a metal recovery apparatus and a metal recovery method for recovering metal present in water in the form of ions.

  In recent years, effective use of water resources is required due to industrial development and population growth. For this purpose, it is important to reuse wastewater such as industrial wastewater. In order to reuse wastewater, it is necessary to purify water, that is, to separate other substances from the water. As a method for separating other substances from water, there are various methods such as a membrane separation method, a centrifugal separation method, an activated carbon adsorption method, an ozone treatment method, and a removal method of suspended substances by aggregation. Using these methods, it is possible to remove substances having a large environmental impact such as phosphorus and nitrogen contained in water, and to remove oils and clays dispersed in water.

  Among these various water treatment methods, the membrane separation method is one of the most commonly used methods for removing insoluble substances in water. From the viewpoint of increasing the water flow rate of the contained water, filter aids are used in membrane separation methods.

  On the other hand, as a method for removing harmful substances and valuables from water, a method is known in which some kind of reaction is caused to a substance dissolved in water to cause precipitation as a precipitate, followed by solid-liquid separation. For example, Patent Document 1 describes a method in which copper ions in water are precipitated, a polymer having an aggregating function is added to aggregate precipitated copper, and copper is separated and recovered as an aggregate.

JP 2006-122817 A

  However, in the conventional method, since the aggregate itself contains a large amount of polymer, there is a problem that the copper purity per unit volume of the aggregate is low and the recovery efficiency is low. In addition, there is a problem that the amount of sludge remaining after separating copper from the agglomerate is large, and the sludge is finally discarded.

  The present invention has been made in order to solve the above-mentioned problems, and does not require a special reaction operation, and is capable of directly solid-liquid separating fine metal compound crystal particles precipitated in water, and a metal recovery apparatus. It aims to provide a method.

  In the metal recovery device according to the embodiment described herein, a precipitation tank for depositing crystal particles of a metal compound from water to be treated containing metal ions, and an average particle size of single particles or aggregates containing a magnetic substance is 0.5 to Filtration of a filter aid supply device for supplying a filter aid of 20 μm, a mixing tank for mixing the filter aid and dispersion medium supplied from the filter aid supply device, and a mixture supplied from the mixing tank. And a solid-liquid separation device having a filter on which the water to be treated supplied from the precipitation tank is filtered to form a deposited layer of the metal compound crystal particles in the water to be treated and the filter aid in the mixture; The treated water supply line for supplying the treated water from the precipitation tank to the solid-liquid separator and the treated water supply line, and the mixture from the mixing tank is joined to the treated water. Mixing line and the fill A stripping water supply line for supplying stripping water for stripping and removing the deposited layer from above onto the filter, and metal compound crystal particles contained in the stripped material discharged together with stripping water from the solid-liquid separator, A separation tank for separating the filter aid, a peeled material discharge line for discharging the peeled material from the solid-liquid separator to the separation tank, and a filter aid supply device for separating the filter aid separated in the separation tank. And a filter-auxiliary agent return line.

  In addition, the metal recovery apparatus according to the embodiment described herein mixes a filter aid having an average diameter of 0.5 to 20 μm with single particles or aggregates containing a magnetic substance and water to be treated containing metal ions, A mixed precipitation tank for making the water to be treated alkaline and depositing crystal particles of a metal compound, a filter aid supply device for supplying the filter aid to the mixed precipitation tank, and a treatment to be supplied from the mixed precipitation tank The solid solution having a filter that filters water and filters the mixture supplied from the mixing precipitation tank and forms a deposition layer of metal compound crystal particles in the water to be treated and a filter aid in the mixture on the water. A liquid separator, a water supply line for supplying water to be treated from the mixed precipitation tank to the solid-liquid separator, and peeling water for peeling and removing the deposited layer from the filter. Phi A separation water supply line that is supplied onto the separator, a separation tank that separates the metal compound and filter aid contained in the peeled material discharged together with the separation water from the solid-liquid separation device, and the separation from the solid-liquid separation device It has a peeling thing discharge line which discharges the exfoliation thing to a tank, and a filter aid return line which returns the filter aid separated by the separation tank to the filter aid supply device.

  In the metal recovery method according to the embodiment described herein, (a) a crystal particle of a metal compound is precipitated from water to be treated containing metal ions, and (b) an average diameter of single particles or aggregates containing a magnetic substance. Is prepared by mixing the filter aid of 0.5 to 20 μm and the water to be treated, and (c) filtering the mixture with a filter of a solid-liquid separator, and depositing the filter aid on the filter. And (d) supplying the water to be treated onto the filter, allowing the water to be treated to permeate the filter aid layer, and the metal compound crystal particles contained in the water to be treated. (E) supplying stripping water to the solid-liquid separator, stripping and removing the metal compound crystal particles together with the filter aid from above the filter with stripping water, and (f) stripping The metal compound crystal particles from the removed filter aid Separated and recovered, reused in (g) the separated recovered filter aid (b) step, characterized by.

  Further, the metal recovery method according to the embodiment described herein includes (i) precipitating crystal particles of a metal compound from water to be treated containing metal ions, and (ii) single particles or aggregates including a magnetic substance. A slurry aid is prepared by mixing a filter aid having an average diameter of 0.5 to 20 μm and the water to be treated. (Iii) The slurry solution is filtered by a filter of a solid-liquid separator, and the filtration is performed on the filter. A filter aid / metal compound crystal particle mixed layer is formed by depositing an auxiliary agent and metal compound crystal particles, and (iv) supplying stripping water to the solid-liquid separator, and filtering aid from above the filter by stripping water. The metal compound crystal particles are peeled and removed together with the agent, (v) the metal compound crystal particles are separated and recovered from the removed filter aid, and (vi) the separated and recovered filter aid is reused in the step (ii). It is characterized by.

The block diagram which shows the metal collection | recovery apparatus which concerns on 1st Embodiment. Process drawing which shows the metal collection | recovery method by the precoat method using the apparatus of FIG. (A) is a cross-sectional schematic diagram which shows the magnetic body particle | grains coat | covered with the polymer, (b) is a cross-sectional schematic diagram which shows the aggregate which the magnetic body particle aggregated. The block diagram which shows the metal collection | recovery apparatus which concerns on 2nd Embodiment. Process drawing which shows the metal collection | recovery method by the body feed method using the apparatus of FIG. The block diagram which shows the metal collection | recovery apparatus which concerns on 3rd Embodiment.

  The inventors of the present application have conducted many experiments on direct solid-liquid separation of copper hydroxide precipitates in wastewater using a filtration membrane, and as a result of various studies, copper hydroxide precipitates precipitated from wastewater. Since the particle diameter (initial diameter) of this was too fine, it was found that it was difficult to directly filter it. The embodiment described here has been made based on such knowledge.

  Various embodiments will be described below.

  (1) A metal recovery apparatus according to an embodiment described herein includes a precipitation tank 2 for precipitating crystal particles of a metal compound from water to be treated containing metal ions, and an average particle diameter of single particles or aggregates containing a magnetic substance. Is supplied from the mixing tank, a filter aid supplying device 5 for supplying a filter aid of 0.5 to 20 μm, a mixing tank 6 for mixing the filter aid supplied from the filter aid supplying apparatus and the dispersion medium, and A filter that forms a deposition layer of the metal compound crystal particles in the water to be treated and the filter aid in the mixture by filtering the water to be treated supplied from the precipitation tank. Solid-liquid separation device 3, treated water supply line L2 for supplying treated water from the precipitation tank to the solid-liquid separation device, connected to the treated water supply line, and the mixture from the mixing tank A mixing line L7 for joining the water to be treated, and the Stripping water supply line L31 for supplying stripping water for stripping and removing the deposited layer from the filter onto the filter, and metal compound crystals contained in the stripped material discharged together with the stripping water from the solid-liquid separator Separation tank 4 for separating particles and filter aid, stripped material discharge line L4 for discharging the stripped material from the solid-liquid separator to the separation tank, and filtering the filter aid separated in the separation tank. And a filter aid return line L5 for returning to the aid supply device.

  In this embodiment, the water to be treated is made alkaline in the precipitation tank to precipitate the metal compound crystal particles, and in the mixing tank, a single particle or agglomerate containing a magnetic substance is dispersed with a filter aid having an average particle diameter of 0.5 to 20 μm. The mixture is supplied to the solid-liquid separation device from the mixing tank via the treated water supply line, a deposited layer of filter aid is formed on the filter, and then the treated water supply line is used. The water to be treated is supplied from the precipitation tank to the solid-liquid separator, the water to be treated is permeated through the filter aid layer, and the crystal particles of the metal compound are captured by the filter aid. Further, the peel water is supplied via the peel water supply line. Is supplied to the solid-liquid separator, and the crystal particles of the metal compound are peeled and removed from the filter together with the filter aid, and the peeled material is discharged from the solid-liquid separator to the separation tank via the peeled material discharge line. Filter aid removed by washing While separating the crystal particles of the metal compound and collecting the separated metal compound crystal particles, the filter aid separated and recovered from the separation tank to the filter aid supply device via the filter aid return line is returned to the filter aid. The filter aid separated and recovered in the agent supply device can be reused, and the precipitated metal compound crystal particles with a fine particle size are directly solid-liquid separated from the water to be treated without requiring a special reaction operation. (FIGS. 1 and 6). Examples of metals that can be precipitated in the form of crystal grains of metal compounds in water include copper, zinc, aluminum, cadmium, gallium, gold, silver, iron, chromium, cobalt, nickel, lead, beryllium, magnesium, and manganese. The metal recovery apparatus and the metal recovery method according to the embodiments described herein are used to recover these metals present in the form of ions in water. In the embodiment described here, the metal compound includes a hydroxide and a hydroxide salt. In the embodiment described herein, copper hydroxide as an example of a metal compound includes not only copper (II) hydroxide but also double salts and mixed salts containing copper hydroxide. For example, a combination of copper carbonate and copper hydroxide, copper sulfate and copper hydroxide, or the like can be given.

  (2) In the apparatus of (1) above, the filter aid is composed of an aggregate formed by aggregating magnetic particles whose surfaces are coated with a polymer, and the average particle diameter D1 of the magnetic particles is in the range of 0.5 to 20 μm. It is preferable that the average aggregate diameter D2 of the aggregate satisfies D1 <D2 ≦ 20 μm, and the average coating thickness t of the polymer satisfies 0.01 ≦ t ≦ 0.25 μm (FIG. 3).

  In this embodiment, the average particle diameter D1 of the magnetic particles is preferably in the range of 0.5 to 20 μm, more preferably the diameter D1 is in the range of 0.5 to 15 μm. When the average particle diameter D1 of the magnetic particles is less than 0.5 μm, the particles are too densely aggregated and the distance between the particles becomes too small, making it difficult to obtain an effective water flow rate. On the other hand, when the average particle diameter D1 exceeds 20 μm, the particles are coarsely aggregated and the distance between the particles becomes too large, making it easy to pass fine precipitates in water, and the recovery efficiency of precipitated copper hydroxide is greatly increased. It will decline. Further, when the average particle diameter D1 is set to 15 μm or less, the recovery efficiency of the copper hydroxide particles is further improved. By the way, the inventors of the present application have obtained knowledge that by performing a verification test, effective copper recovery efficiency cannot be achieved when the average particle diameter D1 of the magnetic particles is, for example, 26 μm. This also shows that when the average particle diameter D1 of the magnetic particles becomes excessive, the copper recovery efficiency decreases.

  In the present embodiment, the average aggregate diameter D2 of the aggregates of the magnetic particles preferably satisfies D1 <D2 ≦ 20 μm, but more preferably satisfies D1 <D2 ≦ 15 μm. When the average aggregate diameter D2 of the aggregates exceeds 20 μm, it becomes easy to pass fine precipitates in water as described above, and the recovery efficiency of copper hydroxide decreases. Further, when the average agglomerated diameter D2 is set to 15 μm, the recovery efficiency of the copper hydroxide particles is further improved as described above.

  In this embodiment, the average coating thickness t of the polymer preferably satisfies 0.01 ≦ t ≦ 0.25 μm, but more preferably the thickness t satisfies 0.01 ≦ t ≦ 0.15 μm. When the average coating thickness t of the polymer is less than 0.01 μm, not only the desired coating effect cannot be obtained, but the strength of the agglomerates is lowered and cannot be used. On the other hand, when the coating thickness t exceeds 0.25 μm, the gap between the magnetic particles in the aggregate is filled with resin, not only the flow rate of the water to be treated is decreased, but also the unevenness is reduced. The recovery efficiency of copper hydroxide tends to decrease. Furthermore, when the coating thickness t is 0.15 μm or less, since it has moderate irregularities, the capturing performance for capturing copper hydroxide particles is increased, and the water flow rate of the water to be treated is increased, so that the copper hydroxide recovery efficiency is increased. Further improve.

  (3) In either of the above-mentioned apparatuses (1) or (2), the apparatus is connected to the upper part of the introduction space of the solid-liquid separator, and tap water is supplied to the introduction space to be included in the deposited layer on the filter. It is preferable to further have a desalting line L10 for removing ions in the copper compound (FIG. 6).

  According to this embodiment, a large amount of tap water is introduced into the introduction space of the solid-liquid separation device via the desalting line, and ions (Na ions, Ca ions, Mg ions, etc.) contained in the deposited layer are introduced. It can be effectively removed.

  (4) In the apparatus of any one of the above (1) to (3), connected to the side portion of the introduction space of the solid-liquid separator, and tap water is supplied from the side to the introduction space and deposited from above the filter. It is preferable to further have a cleaning line L11 for peeling off and removing the layers (FIG. 6).

  According to the present embodiment, a sufficient amount of tap water is introduced from the side into the introduction space of the solid-liquid separator via the washing line, and the deposited layer is peeled off from the filter by the water pressure and removed. be able to. In this case, if an injection nozzle is attached to the connection portion between the cleaning line and the solid-liquid separation device and water is jetted vigorously from the nozzle, the effect of removing the deposited layer is enhanced and the removal efficiency is improved.

  (5) The metal recovery apparatus according to the embodiment described herein mixes a filter aid having an average diameter of 0.5 to 20 μm with single particles or aggregates containing a magnetic substance and water to be treated containing metal ions, Supplied from the mixed precipitation tank 2A for making the water to be treated alkaline and depositing crystal particles of the metal compound, a filter aid supply device 5 for supplying the filter aid to the mixed precipitation tank, and the mixed precipitation tank A filter that filters the water to be treated, filters the mixture supplied from the mixing precipitation tank, and forms a deposited layer of the metal compound crystal particles in the water to be treated and the filter aid in the mixture on the filter. A solid-liquid separation device 3 having, a treated water supply line L2 for supplying treated water from the mixed precipitation tank to the solid-liquid separation device, and for removing the deposited layer by peeling off the filter Release water The separation water supply line L31 to be supplied onto the separator, the separation tank 4 for separating the metal compound and the filter aid contained in the peeled material discharged together with the separation water from the solid-liquid separation device, and the solid-liquid separation device. A separation product discharge line L4 for discharging the separation product to the separation tank, and a filter aid return line L5 for returning the filter aid separated in the separation tank to the filter aid supply device.

  In the present embodiment, the water to be treated is made alkaline in the mixed precipitation tank to precipitate metal compound crystal particles, and the filter aid is supplied from the filter aid supply device into the mixed precipitation tank, and the metal compound is supplied to the filter aid. The crystal particles are adsorbed and captured, and the water to be treated is supplied from the mixed precipitation tank to the solid-liquid separation device via the water to be treated supply line. A filter aid / metal compound crystal particle mixed layer is formed by depositing, and further, stripping water is supplied to the solid-liquid separator through the stripping water supply line, and the crystal particles of the metal compound are combined with the filter aid from above the filter. The exfoliated material is removed from the solid-liquid separation device through the exfoliated material discharge line to the separation tank, and the crystal particles of the metal compound are separated from the filter aid washed and removed in the separation tank. Result While collecting particles, return the filter aid separated and recovered from the separation tank to the filter aid supply device via the filter aid return line, and reuse the filter aid separated and recovered in the filter aid supply device Thus, the crystal particles of the metal compound having a fine particle size can be directly separated from the water to be treated without requiring a special reaction operation (FIG. 4).

  (6) In the apparatus of (5) above, the filter aid is composed of an aggregate formed by aggregating magnetic particles whose surfaces are coated with a polymer, and the average particle diameter D1 of the magnetic particles is in the range of 0.5 to 20 μm. It is preferable that the average aggregate diameter D2 of the aggregate satisfies D1 <D2 ≦ 20 μm, and the average coating thickness t of the polymer satisfies 0.01 ≦ t ≦ 0.25 μm (FIG. 3).

  In the present embodiment, the same effect as the above (2) can be obtained.

  (7) In the metal recovery method of the embodiment described here, (a) crystal particles of a metal compound are precipitated from water to be treated containing metal ions, and (b) single particles or aggregates containing a magnetic substance A mixture of a filter aid having an average diameter of 0.5 to 20 μm and the water to be treated is prepared. (C) The mixture is filtered by a filter of a solid-liquid separator, and the filter aid is placed on the filter. And (d) supplying the water to be treated onto the filter, allowing the water to be treated to permeate the filter aid layer, and the metal compound contained in the water to be treated. Crystal particles are captured by the filter aid, (e) stripping water is supplied to the solid-liquid separator, and the metal compound crystal particles are stripped and removed from the filter together with the filter aid by stripping water, (f ) The metal compound crystal grains from the removed filter aid The separated and recovered, reused in (g) the separated recovered filter aid (b) step.

  In the present embodiment, the water to be treated is made alkaline to precipitate crystal particles of the metal compound, and a single particle or agglomerate containing a magnetic substance is mixed with a filter aid having a mean diameter of 0.5 to 20 μm and a dispersion medium. The mixture is supplied from the mixing tank to the solid-liquid separator via the water supply line to be treated, and a deposition layer of filter aid is formed on the filter, and then the solid-liquid separator from the precipitation tank via the water to be treated supply line The water to be treated is supplied to the filter aid layer so that the water to be treated passes through the filter aid layer, and the crystal particles of the metal compound are captured by the filter aid. Then, the crystal particles of the metal compound are peeled and removed together with the filter aid from the filter, and the peeled material is discharged from the solid-liquid separation device to the separation tank via the peeled material discharge line. Separate crystal particles of metal compounds While collecting the separated crystal particles of the metal compound, the filter aid separated and recovered from the separation tank is returned to the filter aid supply device via the filter aid return line, and the filter aid separated and recovered by the filter aid supply device is recovered. The agent can be reused, and the crystal particles of the fine metal particle precipitated can be directly separated from the water to be treated without requiring a special reaction operation (FIG. 2).

  (8) In the metal recovery method of the embodiment described herein, (i) a crystal particle of a metal compound is precipitated from water to be treated containing metal ions, and (ii) single particles or aggregates including a magnetic substance A slurry aid is prepared by mixing a filter aid having an average diameter of 0.5 to 20 μm and the water to be treated. (Iii) The slurry solution is filtered by a filter of a solid-liquid separator, and the filtration is performed on the filter. A filter aid / metal compound crystal particle mixed layer is formed by depositing an auxiliary agent and metal compound crystal particles, and (iv) supplying stripping water to the solid-liquid separator, and filtering aid from above the filter by stripping water. The metal compound crystal particles are peeled and removed together with the agent, (v) the metal compound crystal particles are separated and recovered from the removed filter aid, and (vi) the separated and recovered filter aid is reused in the step (ii). To do.

  In the present embodiment, the water to be treated is made alkaline to precipitate metal compound crystal particles, a filter aid is added thereto, the precipitated metal compound crystal particles are captured by the filter aid, and the water to be treated is supplied. The water to be treated is supplied from the mixed precipitation tank to the solid-liquid separation device through the filter, and the filter aid / metal compound crystal particles are formed by depositing the filter aid and the metal compound crystal particles on the filter in the solid-liquid separation device. A mixed layer is formed, stripping water is further supplied to the solid-liquid separation device through the stripping water supply line, and the crystal particles of the metal compound are stripped and removed together with the filter aid from the filter, and the solid particles are separated through the stripping material discharge line. The exfoliation material is discharged from the liquid separator to the separation tank, and the crystal particles of the metal compound are separated from the filter aid washed and removed in the separation tank, and the separated crystal particles of the metal compound are recovered, while the filter aid return line Through The filter aid separated and recovered from the separation tank to the filter aid supply device can be returned, and the filter aid separated and recovered in the filter aid supply device can be reused and deposited without requiring a special reaction operation. The crystal particles of the metal compound having a fine particle size can be directly solid-liquid separated from the water to be treated (FIG. 5).

  Hereinafter, various preferred embodiments and specific examples thereof will be described with reference to the accompanying drawings.

  In the embodiments or examples described below, an aqueous alkali solution is directly introduced into water to be treated containing copper ions such as an aqueous copper sulfate solution to precipitate copper hydroxide. The type of alkali is not particularly limited, but sodium hydroxide is most suitable. Such direct charging of the alkali solution makes the particle size of the copper particles precipitated fine, and separation from water becomes very difficult. However, since the fine copper compound particles (average particle diameter of 0.01 to 10 μm) can be removed by using the method of the present embodiment, the number of processes is reduced and the apparatus is easily simplified.

  There are two types of metal recovery methods, a pre-coating method and a body feed method, but the apparatus used for each method is different in configuration, so each will be described below.

(First embodiment)
First, with reference to FIG. 1, the metal recovery apparatus used for the precoat method as 1st Embodiment is demonstrated. Although this embodiment describes the case of recovering copper, any metal that can precipitate metal compound crystal particles in water can be applied.

  The metal recovery apparatus 1 of this embodiment is an apparatus used for the precoat method, and is effectively used particularly when the concentration of the copper compound precipitated in the water to be treated is low. The metal recovery apparatus 1 has a precipitation tank 2, a solid-liquid separation apparatus 3, a separation tank 4, a filter aid tank 5, a mixing tank 6, a raw water supply source (not shown), an alkali addition apparatus, and a copper concentrated water storage tank. These devices and apparatuses are connected to each other by a plurality of piping lines L1 to L8. Various pumps P1 to P9, valves V1 to V3, measuring instruments and sensors (not shown) are attached to the piping lines L1 to L8. Detection signals are input from these measuring instruments and sensors to an input section of a controller (not shown), and control signals are output from the output section of the controller to pumps P1 to P9 and valves V1 to V3, respectively, and their operations are controlled. It has become so. As described above, the entire metal recovery apparatus 1 is comprehensively controlled by a controller (not shown).

  The precipitation tank 2 has a stirring screw that stirs the water to be treated. Factory drainage containing copper ions serving as the water to be treated is introduced from a raw water supply source (not shown) via the line L1 to temporarily store the water to be treated. During storage, an appropriate amount of sodium hydroxide (NaOH) is introduced from an alkali addition device (not shown) to precipitate copper ions contained in the water to be treated as copper hydroxide.

  The solid-liquid separation device 3 includes a filter 33 that partitions the interior into an upper introduction space 31 and a lower discharge space 32. As the filter 33, for example, a polymer fiber such as polyester, nylon, polypropylene, fluorine fiber, or cellulose acetate knitted with a plain weave, a twill weave, a double weave, or the like can be used. The filter thickness is approximately 1 mm or less, and the filter aperture is approximately 1 to 20 μm.

  The introduction space 31 of the solid-liquid separator is connected to the precipitation tank 2 via a water to be treated supply line L2 having a pressure pump P1. Further, a cleaning line L31 having a pump P5 and a cleaning discharge water line L4 are respectively connected to the side portions of the introduction space 31.

  On the other hand, the discharge space 32 of the solid-liquid separator is connected to a treated water distribution line L3 having three three-way valves V1, V2, and V3. At the first three-way valve V1, the above-described separation water supply line L31 branches from the treated water distribution line L3. A treated water line L32 having a pump P2 branches from the treated water distribution line L3 at the second three-way valve V2. At the third three-way valve V3, two lines L33 and L34 are branched from the treated water distribution line L3. One branch line L33 has a pump P4 and is connected to a separation tank 4 described later. The other branch line L34 has a pump P5 and is connected to a mixing tank 6 described later.

  The separation tank 4 has a stirring screw for stirring the washing discharged water received from the introduction space 31 of the solid-liquid separation device through the peeled material discharge line L4, and separates into a precipitated copper compound and a filter aid. An electromagnet 41 is built in. The electromagnet 41 is connected to a power source (not shown) that is on / off controlled by a controller (not shown).

  In addition to the separated product discharge line L4, a branch line L33 branched from the treated water distribution line L3 is connected to the upper part of the separation tank 4, and a part of the treated water that has passed through the filter 33 of the solid-liquid separator is part of it. A part of the treated water is supplied to the separation tank 4 and reused in the separation tank 4. On the other hand, a copper concentrate discharge line L8 and a filter aid return line L5 are connected to the lower part of the separation tank 4, respectively. The copper concentrate discharge line L8 has a pump P9 and is a pipe for discharging copper concentrate from the separation tank 4 to a storage tank (not shown). The filter aid return line L5 has a pump P6 and is a pipe for returning the filter aid separated from the separation tank 4 to the filter aid tank 5.

  The filter aid tank 5 is newly replenished with a filter aid supply source (not shown), and the filter aid separated in the separation tank 4 is returned through the above-described filter aid return line L5. It has become so. The filter aid tank 5 is adapted to supply an appropriate amount of filter aid to the mixing tank 6 via a filter aid supply line L6 having a pump P7.

  The mixing tank 6 has a stirring screw for stirring water, and a dispersion medium is added to the filter aid supplied from the filter aid tank 5 and mixed by stirring. ). It is preferable to use water as the dispersion medium. A branch line L34 branched from the treated water distribution line L3 is connected to the upper part of the mixing tank 6, and a part of the treated water that has passed through the filter 33 of the solid-liquid separator is supplied to the mixing tank 6. A part of the treated water is reused as a dispersion medium.

  In addition, a mixing line L7 having a pump P8 communicates with an appropriate place of the mixing tank 6. The mixing line L7 is connected and joined at an appropriate position of the treated water supply line L2. The mixture (suspension) containing the filter aid from the mixing line L7 is added to the water to be treated flowing through the water to be treated supply line L2. A flow rate control valve (not shown) is attached to the mixing line L7, and the flow rate of the mixture (suspension) containing the filter aid is adjusted by the controller.

(First metal recovery method)
Next, with reference to FIG. 2 and FIG. 1, the precoat method as a 1st metal collection | recovery method using said apparatus is demonstrated.

  First, the magnetic substance-containing filter aid and the dispersion medium are mixed in the mixing tank 6 to prepare a suspension containing the filter aid (step S1). The filter aid includes magnetic particles and may further include a polymer that coats the magnetic particles. As the dispersion medium, water is mainly used, but other dispersion mediums can be appropriately used. The concentration of the filter aid in the suspension is not particularly limited as long as a precoat layer, that is, a particle deposition layer can be formed by the following operation, but is adjusted to, for example, about 10,000 to 200,000 mg / L.

  Next, the suspension is passed through the filter 33 of the solid-liquid separator 3, the filter aid in the suspension is filtered off, and is left on the filter. Layer) is formed (step S2). In addition, the water flow to the filter 33 by the pressurizing pump P1 is performed at a predetermined pressure. In addition, since the precoat layer is formed and held by the action of external force as described above, the above-described filtering is performed, for example, by placing the filter so as to close a container opening of a predetermined container. The filter aid remains on the filter 33 so that it is arranged and stacked. In this case, the precoat layer is formed and held by the external force from the wall surface of the container and the downward external force (gravity) due to the weight of the filter aid positioned above. The thickness of the precoat layer varies depending on the concentration of the liquid to be processed, but is about 0.5 to 10 mm.

  Next, the waste water on which the copper compound is deposited is passed through the precoat layer formed as described above to remove insoluble matters (step S3). Water flow is mainly performed under pressure. At this time, the copper compound (mainly copper hydroxide) is removed by adsorbing on the surface of the precoat layer, specifically, the filter aid constituting the precoat layer. At this time, by setting the filter aid to a special configuration as described later, this insoluble matter can be trapped and a sufficient water flow rate can be obtained.

  After removing the copper compound in water, the precoat layer is dispersed in the dispersion medium, the precoat layer is decomposed into a filter aid, and the filter aid is washed (step S4). This cleaning may be performed in a container in which a filter is installed, or may be performed in another container. When using other containers, the precoat layer is decomposed into filter aids by means such as washing, and then transported. Although water is used for washing, washing with a surfactant or an organic solvent is also possible.

  Next, the washed filter aid is recovered using magnetic separation (step S5). The method of magnetic separation is not particularly limited, but there are a method of collecting permanent magnets or electromagnets in a container and recovering, a method of recovering particles by opening a magnetic field by recovering with a metal mesh magnetized by a magnet, etc. Can be mentioned. Specifically, after the filter aid is fixed with an electromagnet, the cleaning liquid is discharged from the drain of the cleaning container, or the filter aid is fixed with an electromagnet and then moved to another container and collected.

  In the first copper recovery method, a precoat layer is formed on the filter in advance, and then drainage is passed through, so that the amount of copper compound adsorbed on the surface of the filter aid increases with the treatment time. . As a result, especially the excessively adsorbed copper compound embeds the voids of the filter aid, so that the water flow rate is reduced. Therefore, as described above, the first method is effective when the concentration of the copper compound in water is low.

(Filter aid)
Next, the filter aid will be described in detail.

  As the filter aid, one containing magnetic particles and having an average particle size in the range of 0.5 to 20 μm is used. The filter aid may be a single particle of magnetic material, or the surface of the magnetic particle 11 may be coated with a coating agent 12 such as a polymer as shown in FIG. The filter aid may be an aggregate 13 in which the polymer-coated magnetic particles 11 are aggregated as shown in FIG.

  More preferably, the filter aid has an average particle diameter D1 of the magnetic substance of 0.5 to 20 μm, and the magnetic substance is partly aggregated by the polymer or trialkoxysilane, and the average aggregate diameter D2 is D1 <D2 ≦ 20 μm. And the polymer surface coating thickness t is preferably in the range of 0.01 ≦ t ≦ 0.25 μm. Here, the average particle diameter is measured by a laser diffraction method. Specifically, it can be measured by a SALD-DS21 type measuring device (trade name) manufactured by Shimadzu Corporation. When the average particle diameter of the magnetic material as the primary particles exceeds 20 μm, the distance between the particles becomes too large, and fine precipitates in water described later may pass therethrough. On the other hand, when the primary particle diameter is smaller than 0.5 μm, the particles are densely aggregated and fine precipitates in the water can be removed, but an effective water flow rate may not be obtained.

For example, a ferromagnetic substance can be generally used as the magnetic material, and examples thereof include iron and iron-containing alloys, magnetite, titanite, pyrrhotite, magnesia ferrite, cobalt ferrite, nickel ferrite, barium ferrite, and the like. . Of these, ferrite compounds having excellent stability in water can achieve the present invention more effectively. For example, magnetite (Fe ₃ O ₄ ), which is a magnetite, is preferable because it is not only inexpensive, but also stable as a magnetic substance in water and safe as an element, so that it can be easily used for water treatment. The magnetic body can take various shapes such as a spherical shape, a polyhedron, and an indeterminate shape, but is not particularly limited. The particle size and shape of the magnetic material desirable for use may be appropriately selected in view of the manufacturing cost, and a polyhedral structure with spherical or chamfered corners is particularly preferable. These magnetic materials may be subjected to normal plating treatment such as Cu plating and Ni plating if necessary.

  In addition, in an aggregate in which magnetic particles whose surfaces are coated with a polymer are aggregated, primary particles having a core / shell structure in which the magnetic material is a core and a polymer layer covering the surface constitutes a shell are aggregated to aggregate. It constitutes a collection.

  In the present invention, as the polymer that coats the surface of the magnetic particles and aggregates the particles, a suitable material can be selected according to the purpose. Preferably, it is easy to coat on a magnetic material, and is strongly adhered to polyacrylonitrile, polymethyl methacrylate, polystyrene, fluororesin and copolymers thereof having acid resistance and alkali resistance, a phenol resin excellent in dispersion in water, and a magnetic material. A trialkoxysilane condensate having high stability in water is preferably used. The average surface coating thickness t of this polymer is preferably coated such that 0.01 ≦ t ≦ 0.25 μm. If it is thinner than 0.01μm, the strength of the secondary agglomerates will be weak and it may be difficult to use it in water. If it is thicker than 0.25μm, the gap between particles will be narrow, which is effective when used as a filter aid. May not be able to secure a reasonable water flow rate. The polymer coating amount may be measured by observation with an optical microscope, a scanning electron microscope (SEM), etc., but preferably it is raised to a high temperature in an oxygen-free state, and the filter aid is thermally decomposed to reduce the weight. That is, when the polymer coating amount is obtained and the average thickness of the polymer layer is calculated from the specific surface area of the particles, it can be accurately obtained.

  In addition, when the above-described magnetic substance includes an aggregate in which particles coated with a polymer are aggregated, the aggregate preferably has a characteristic shape. That is, in the filter aid according to the present embodiment, the average aggregate diameter D2 of the aggregate satisfies D1 <D2 ≦ 20 μm, where the average particle diameter of the magnetic substance is D1. When the particles are aggregated at this size, the particle diameter is not neatly aggregated into a spherical shape and formed into an irregular shape. By having this irregular shape, when used as a filter aid or precoat material, it has moderate voids during filtration deposition, and it is possible to obtain a filtration flow rate while trapping copper compounds in the water to be treated. it can. If the average aggregate diameter D2 of the aggregates 13 exceeds 20 μm and becomes too large, the gaps between the aggregates may increase, and copper precipitates in water may not be trapped. Further, it is more preferable that D1 <D2 ≦ 15 μm. This is because it becomes easier to trap copper precipitates in the water by setting the average aggregate diameter D2 of the aggregates to 15 μm or less.

  The filter aid used in the embodiment described herein can be produced by any method as long as it can realize the structure of the filter aid as described above. As an example of such a method, a polymer is dissolved in an organic solvent capable of dissolving the polymer, a composition in which a magnetic material is dispersed in the solution is prepared, and the organic solvent is removed by spraying the composition. A spray drying method is mentioned. According to this method, the average particle diameter of the secondary aggregate in which the primary particles are aggregated can be adjusted by adjusting the environmental temperature of spray drying, the ejection speed, and the like, and the organic solvent can be removed from between the aggregated primary particles. When removed, pores are formed, and a suitable porous structure can be easily formed.

  On the other hand, industrially, a polymer solution was prepared by dissolving a polymer in a solvent capable of dissolving the polymer, and the polymer solution was poured onto the surface of a magnetic body placed in a mold, and the solvent was removed and solidified. The filter aid according to the present invention can also be formed by crushing a product, or crushing a product obtained by removing an organic solvent from a composition in which a magnetic material is dispersed in a polymer solution and crushing the product. Moreover, a filter aid can be manufactured by dripping the composition which melt | dissolved the polymer in the solvent to a Henschel mixer, a ball mill, or a granulator, and making it dry. At this time, a preferred filter aid can be produced through two steps of production conditions for covering the surface of the magnetic material and conditions for aggregating the magnetic material.

  Next, a method for adjusting the polymer coating thickness during production and a method for adjusting the aggregate diameter of the aggregate in which the polymer-coated magnetic particles are aggregated will be described.

  In order to determine the surface coating thickness on the surface of the magnetic material, it is calculated from the mixing ratio of the polymer and the magnetic material, the density of the resin and the specific surface area of the magnetic material. That is, when the volume of the resin to be added is obtained from the weight and density of the resin to be added and divided by the surface area of the magnetic body obtained from the weight and specific surface area of the magnetic body, the average coating thickness t of the polymer is obtained. In addition, the control of the particle size varies depending on the type of spray liquid and the spraying method, but in order to reduce the aggregate, the droplet size of the droplet to be spray-dried can be reduced, for example, the spray pressure of the spray nozzle can be increased. If the spraying speed is slowed or the spraying disk is rotated faster, the particle size of the produced aggregates becomes smaller.

  Next, a method for measuring the thickness of the polymer coating in the already formed aggregate will be described.

  The calculation of the coating thickness of the polymer may be measured by observation with an optical microscope or SEM. However, the polymer coating thickness is preferably raised to a high temperature in an oxygen-free state and the resin composite is thermally decomposed to reduce the weight loss, that is, the polymer coating weight It can be accurately obtained by calculating and calculating the average thickness of the polymer layer from the specific surface area of the particles.

(Second Embodiment)
With reference to FIG. 4, a metal recovery apparatus 1A according to a second embodiment used in the body feed method will be described. Although this embodiment describes the case of recovering copper, any metal that can precipitate metal compound crystal particles in water can be applied. In addition, description of the part which this embodiment overlaps with said embodiment is abbreviate | omitted.

  The metal recovery apparatus 1A of the present embodiment is used for the body feed method, and is effectively used particularly when the copper compound concentration in water is high. The difference between the metal recovery apparatus 1A of the present embodiment and the apparatus 1 of the first embodiment is that the apparatus 1A has no mixing tank 6 and is provided with a mixed precipitation tank 2A instead of the precipitation tank 2. The mixed precipitation tank 2A has both a precipitation function of adding alkali to the water to be treated and precipitating a copper compound, and a mixing function of adding a filter aid to the water to be treated and mixing them. That is, in the metal recovery apparatus 1A of the present embodiment, the filter aid is directly supplied from the filter aid tank 5 into the mixed precipitation tank 2A via the line L6 without going through the mixing tank. Yes.

(Second metal recovery method)
Next, a body feed method as a second metal recovery method using the above apparatus will be described with reference to FIGS.

  Also in this embodiment, the filter aid and the dispersion medium are first mixed to adjust the suspension. The dispersion medium used in this case is treated water existing in the mixed precipitation tank 2A. That is, in this method, the filter aid is directly added to the raw water that is the water to be treated to adjust the suspension from the raw water (step K1). The concentration of the filter aid in the suspension is not particularly limited as long as a filtration layer can be formed by the following operation, but is adjusted to, for example, about 10,000 to 200,000 mg / L.

  Next, the suspension (water to be treated) is passed through a filter, the filter aid in the suspension is filtered off and left on the filter to form a filter layer formed by aggregation of the filter aid (step) K2). In addition, water flow is performed under pressure.

  Moreover, since the filtration layer is formed and held by the action of an external force as described above, the above-described filtering is performed, for example, by placing the filter so as to close a container opening of a predetermined container. The filter aid remains on the filter so that it can be arranged and stacked. In this case, the filtration layer is formed and held by an external force (gravity) downward due to the external force from the wall surface of the container and the weight of the filter aid positioned above.

  After removing the copper compound in the wastewater as described above, the filter layer is dispersed in the dispersion medium, the filter layer is decomposed into a filter aid, and the filter aid is washed (step K3). This cleaning may be performed in a container in which a filter is installed or in another container. When using other containers, the filter layer is decomposed into filter aids using means such as washing, and then transported. Although water is used for washing, washing with a surfactant or an organic solvent is also possible.

  Next, the washed filter aid is recovered using magnetic separation (step K4). The method of magnetic separation is not particularly limited, but there are a method of collecting permanent magnets or electromagnets in a container and recovering, a method of recovering particles by opening a magnetic field by recovering with a metal mesh magnetized by a magnet, etc. Can be mentioned.

  In the second metal recovery method, since the filter aid constituting the filter layer is contained in the water to be treated, that is, the suspension prepared using this water, the copper compound to be removed is removed. The aggregate is always supplied together with the water to be treated (suspension).

  Therefore, even when the amount of the copper compound in the water to be treated (suspension) is large, the supply of the copper compound and the supply of the filter aid are performed at the same time. Like the form, the excessively adsorbed copper compound does not bury the voids of the filter aid. For this reason, the filtration rate can be maintained for a long time. As a result, as described above, the metal recovery method of the second embodiment is effective when the concentration of the copper compound in the wastewater is high.

  In both the first and second metal recovery methods, the recovered copper compound can be easily washed (desalted). That is, it is possible to remove ionic components adhering to the copper compound by passing water through the filter aid and the copper compound deposited on the filter for a certain period of time.

(Third embodiment)
With reference to FIG. 6, the 3rd copper collection | recovery apparatus 1B utilized for a precoat method is demonstrated. In addition, description of the part which this embodiment overlaps with said embodiment is abbreviate | omitted.

  In the metal recovery apparatus 1B of the present embodiment, a desalting line L10 and a stripping water supply line L11, which are two lines for supplying tap water to the introduction space 31 of the solid-liquid separator 3B, are connected to each other. The desalting line L10 is connected to the upper part of the introduction space 31 of the solid-liquid separator 3B, and supplies tap water to the introduction space 31 to remove ions in the copper compound contained in the deposited layer on the filter 33. It is. Introducing abundant amounts of tap water into the introduction space of the solid-liquid separator via the desalting line L10, and effectively removing ions (Na ions, Ca ions, Mg ions, etc.) contained in the sedimentary layer Can do.

  The stripping water supply line L11 is connected to the side portion of the introduction space 31 of the solid-liquid separator 3B, and tap water is supplied to the introduction space 31 from the side to remove the deposited layer from the filter 33 and remove it. is there. A sufficient amount of tap water is introduced from the side into the introduction space 31 of the solid-liquid separator 3B via the peeling water supply line L11, and the deposited layer is peeled off from the filter 33 by the water pressure and removed. Can do. In this case, if an injection nozzle is attached to the connection portion between the separation water supply line L11 and the solid-liquid separation device 3B, and water is ejected vigorously from the nozzle, the effect of removing the deposited layer is enhanced and the removal efficiency is further improved. To do.

  This will be described in more detail below using examples.

[Preparation of filter aid]
The following six types of filter aids A to F were prepared as filter aids used in the water treatment method described above.

(Filter aid A)
Magnetite particles (average particle size 2 μm) were prepared.

(Filter aid B)
Magnetite particles (average particle size 0.5 μm) were prepared.

(Filter aid C)
Magnetite particles (average particle size 5 μm) were prepared.

(Filter aid D)
30 parts by weight of polymethyl methacrylate was dissolved in 3 liters of tetrahydrofuran to obtain a solution, and 300 parts by weight of magnetite particles having an average particle diameter D1 of 2 μm were dispersed in the solution to obtain a composition. The composition is sprayed slowly using a mini spray dryer (B-290 type, manufactured by Shibata Kagaku Co., Ltd.), and a filter aid having an average aggregate diameter (average secondary particle diameter) D2 of about 11 μm aggregated in a spherical shape is obtained. Produced. The average coating thickness t was 0.038 μm.

(Filter aid E)
30 parts by weight of polymethyl methacrylate was dissolved in 3 liters of tetrahydrofuran to obtain a solution, and 300 parts by weight of magnetite particles having an average particle diameter of 2 μm (A) were dispersed in the solution to obtain a composition. This composition was slowly sprayed using a mini spray dryer (B-290 type, manufactured by Shibata Kagaku Co., Ltd.) to prepare a filter aid having an average secondary particle diameter D2 of about 18 μm aggregated in a spherical shape. The average coating thickness was 0.038 μm (C).

(Filter aid F)
40 parts by weight of a resol type phenol resin is dissolved in 3 liters of water to form a solution, and 300 parts by weight of magnetite particles (specific surface area 2.5 m ² / g) having an average particle diameter of 2 μm (A) are dispersed in the solution. To obtain a composition. This composition was sprayed slowly using a mini spray dryer (B-290 type, manufactured by Shibata Kagaku Co., Ltd.) to produce a filter aid having an average secondary particle size of about 11 μm aggregated in a spherical shape. The average coating thickness calculated from the density of the polyphenol resin and the specific surface area of the magnetite was 0.044 μm (C).

Example 1
A device 1 shown schematically in FIG. 1 was produced. To-be-treated water containing copper is supplied to the precipitation tank 2, and an aqueous sodium hydroxide solution (denoted as NaOH in the figure) is added to the precipitation tank to make it alkaline, thereby precipitating copper hydroxide. Moreover, a filter aid is sent from the filter aid tank 5 to the mixing tank 6 and mixed with treated water that is partially reused to produce a filter aid slurry. This filter aid slurry is first sent to the introduction space 31 of the solid-liquid separator 3 to form a filter aid film on the filter 33. Then, the to-be-processed liquid which precipitated copper is supplied to the solid-liquid separation apparatus 3 under pressure, and solid-liquid separation (filtration) is performed with the membrane of the filter aid formed previously. The filtrate is a weakly alkaline treatment liquid from which copper has been removed, and may be drained through a neutralization tank. However, the washing water of the solid-liquid separation device 3, the washing water of the magnet 41 of the separation tank 4, and the filtration of the mixing tank 6 are used. It can also be used as a liquid when preparing an auxiliary slurry. When filtration of the water to be treated is completed, the filter 33 in the solid-liquid separator 3 has a cake of the filter aid and the precipitated copper compound. In order to peel this, peeling water is supplied from the side of the filter 33 to break up the cake, which is then supplied to the separation tank 4. The separation tank 4 includes a stirring mechanism and a magnet 41 (magnetic separation mechanism), separates the filter aid and the copper compound while mixing, and collects and separates only the filter aid with a magnet. The liquid recovered from the filter aid is recovered as copper concentrated water containing a high concentration of copper compound, washed with the supplied wash water, and returned to the filter aid tank 5. The filter aid returned in this way is supplied to the mixing tank 6 and reused.

  As water to be treated, an aqueous copper sulfate solution containing 50 mg / L in terms of copper was prepared. This was supplied to the precipitation tank 2, and 48% sodium hydroxide was further added dropwise to adjust the pH to 10. When mixed for a while, precipitation of a mixed salt (copper) compound of copper hydroxide and copper sulfate containing light green copper hydroxide as a main component was confirmed.

  Moreover, the filter aid was supplied from the filter aid tank 5 filled with the filter aid A to the mixing tank 6 and mixed with water to prepare a filter aid slurry. This was supplied to the solid-liquid separator 3, and a layer of filter aid having an average thickness of 1 mm was produced on the filter 33. After that, when water to be treated was supplied from the precipitation tank 2 to the solid-liquid separator 3 and filtered, it was confirmed that 99% or more of copper in the filtrate (treated water) was recovered. After the filtration treatment, washing water was supplied from the side of the filter 33 of the solid-liquid separator 3, and the layer formed on the filter 33 was broken and supplied to the separation tank 4. After operating the stirrer in the separation tank 4 to separate the filter aid and the copper compound, the magnet 41 was operated to separate only the filter aid, and the liquid was discharged to obtain a copper concentrate. When the copper concentrate was analyzed, it was confirmed that the main component of the slurry was a mixed salt of copper hydroxide and copper sulfate containing copper hydroxide as the main component. Thereafter, the magnetic field of the magnet 41 was released, cleaning water was supplied to make a filter aid slurry, and then returned to the filter aid tank 5. Thereafter, the mixture was supplied to the mixing tank 6 and the same operation was performed, but it could be reused without any problem.

(Example 2)
A test was performed in the same manner except that filter aid B was used instead of filter aid A using the same apparatus as in Example 1. The recovery rate of copper was 99% or more. Compared with Example 1, the water flow rate of the solid-liquid separator was halved, but it could be operated without problems.

(Example 3)
Using the same apparatus as in Example 1, a test was conducted in the same manner except that filter aid C was used instead of filter aid A. The recovery rate of copper was 99% or more. Compared with Example 1, the water flow rate of the solid-liquid separator almost doubled, but it could be operated without any problems.

(Comparative Example 1)
A test was performed in the same manner except that magnetite particles having an average particle size of 0.3 μm were used in place of the filter aid A using the same apparatus as in Example 1. When filtration was performed, the filter was clogged, and a sufficient filtration flow rate could not be obtained.

Example 4
A device 1A schematically shown in FIG. 4 was produced. Water to be treated containing copper is supplied to the mixed precipitation tank 2A, and an aqueous sodium hydroxide solution (indicated as NaOH in the figure) is added to the mixed precipitation tank 2A to make it alkaline, thereby depositing copper hydroxide. Further, the filter aid is also supplied from the filter aid tank 5 to the mixed precipitation tank 2A, and a mixed slurry of the copper deposit and the filter aid is made. This filter aid slurry is first sent to the solid-liquid separator 3 to form a filter aid film on the filter 33 and to remove the copper compound. The filtrate is a weakly alkaline treatment liquid from which copper has been removed and may be drained through a neutralization tank, but can also be used as stripping water for the solid-liquid separation device 3 and washing water for the magnet 41 in the separation tank 4. . When filtration of the water to be treated is completed, the filter 33 in the solid-liquid separator 3 has a cake of the filter aid and the precipitated copper compound. In order to peel this cake from the filter 33, peeling water is supplied from the side of the filter 33 to break the cake and supply it to the separation tank 4. The separation tank 4 includes a stirring mechanism and a magnet 41 (magnetic separation mechanism), separates the filter aid and the copper compound while mixing, and collects and separates only the filter aid with a magnet. The liquid recovered from the filter aid is recovered as copper concentrated water containing a high concentration of copper compound, washed with the supplied wash water, and returned to the filter aid tank 5. The filter aid returned in this way is supplied to the mixed precipitation tank 2A and reused.

  As the water to be treated, an aqueous copper sulfate solution containing 1000 mg / L in terms of copper was prepared. This was supplied to the mixed precipitation tank 2A, and 48% sodium hydroxide was further added dropwise to adjust the pH to 10. When mixed for a while, precipitation of a mixed salt (copper compound) of copper hydroxide and copper sulfate containing light green copper hydroxide as a main component was confirmed. Moreover, the filter aid was supplied from the filter aid tank 5 filled with the filter aid A to the mixed precipitation tank 2A so as to be 10000 mg / L, thereby preparing a slurry of the filter aid and the copper precipitate. When this was supplied to the solid-liquid separator 3 and filtered on the filter 33, it was confirmed that 99% or more of the copper in the filtrate (treated water) was recovered. After the filtration treatment, washing water was supplied from the side of the filter 33 of the solid-liquid separator 3, and the layer formed on the filter 33 was broken and supplied to the separation tank 4. After operating the stirrer in the separation tank 4 to separate the filter aid and the copper compound, the magnet 41 was operated to separate only the filter aid, and the liquid was discharged to obtain a copper concentrate. When the copper concentrate was analyzed, it was confirmed that the main component of the slurry was a mixed salt of copper hydroxide and copper sulfate containing copper hydroxide as the main component. Thereafter, the magnetic field of the magnet 41 was released, cleaning water was supplied to make a filter aid slurry, and then returned to the filter aid tank 5. Thereafter, the mixture was supplied to the mixed precipitation tank 2A and the same operation was performed, but it could be reused without any problem.

(Example 5)
A test was performed in the same manner except that filter aid D was used instead of filter aid A using the same apparatus as in Example 4. The recovery rate of copper was 99% or more. Although the water flow rate of the solid-liquid separator was 1.3 times that of Example 4, it could be operated without any problems.

(Example 6)
A test was performed in the same manner except that filter aid E was used instead of filter aid A using the same apparatus as in Example 4. The recovery rate of copper was 99% or more. Compared with Example 4, the water flow rate of the solid-liquid separator was approximately doubled, but could be operated without any problems.

(Example 7)
A test was performed in the same manner except that filter aid E was used instead of filter aid A using the same apparatus as in Example 4. The recovery rate of copper was 99% or more. Although the water flow rate of the solid-liquid separator was 1.2 times that of Example 4, the operation was possible without any problem.

(Example 8)
A device 1B schematically shown in FIG. 3 was produced. This device 1B is different from the device 1 of FIG. 1 in that a city water (tap water) supply port communicating with the desalting line L10 is provided at the top of the introduction space 31 of the solid-liquid separation device 3B, and the city water is separated after the solid-liquid separation. To allow desalting. In addition, a city water (tap water) supply port communicating with the separation water supply line L11 is also provided on the side of the introduction space 31 of the solid-liquid separator 3B so that the filter inside the solid-liquid separator can be washed with city water. I made it.

  As in Example 1, an aqueous copper sulfate solution containing 50 mg / L in terms of copper was prepared as the water to be treated. This was supplied to the precipitation tank 2, and 48% sodium hydroxide was further added dropwise to adjust the pH to 10. When mixed for a while, precipitation of a mixed salt (copper compound) of copper hydroxide and copper sulfate containing light green copper hydroxide as a main component was confirmed. Moreover, the filter aid was supplied from the filter aid tank 5 filled with the filter aid A to the mixing tank 6 and mixed with water to prepare a filter aid slurry. This was supplied to the solid-liquid separator 3, and a layer of filter aid having an average thickness of 1 mm was produced on the filter 33. After that, when water to be treated was supplied from the precipitation tank 2 to the solid-liquid separator 3 and filtered, it was confirmed that 99% or more of copper in the filtrate (treated water) was recovered. After the filtration treatment, the water to be treated was switched from the treated water to the city water, and the water flow was continued for 1 minute, and the ion content in the copper compound deposited on the filter 33 was removed. Thereafter, city water was supplied from the side of the filter 33 of the solid-liquid separator 3, and the layer formed on the filter 33 was peeled off and supplied to the separation tank 4. After operating the stirrer in the separation tank 4 to separate the filter aid and the copper compound, the magnet 41 was operated to separate only the filter aid, and the liquid was discharged to obtain a copper concentrate. When the copper concentrate was analyzed, it was confirmed that the main component of the slurry was a mixed salt of copper hydroxide and copper sulfate containing copper hydroxide as the main component. Thereafter, the magnetic field of the magnet was released, washing water was supplied to make a filter aid slurry, and then returned to the filter aid tank 5. Thereafter, the mixture was supplied to the mixing tank 6 and the same operation was performed, but it could be reused without any problem.

Example 9
The same apparatus as in Example 8 was used. As water to be treated, waste water containing 500 mg / L of Cr ³⁺ was prepared. This waste water was accommodated in the precipitation tank 2, sodium hydroxide was added to adjust the waste water to pH 8.5, and Cr ³⁺ in the waste water was precipitated as chromium hydroxide. Moreover, the filter aid was supplied from the filter aid tank 5 filled with the filter aid A to the mixing tank 6 and mixed with water to prepare a filter aid slurry. This was supplied to the solid-liquid separator 3, and a layer of filter aid having an average thickness of 1 mm was produced on the filter 33. After that, when water to be treated was supplied from the precipitation tank 2 to the solid-liquid separator 3 and filtered, it was confirmed that 99% or more of chromium in the filtrate (treated water) was recovered.

(Example 10)
The same apparatus as in Example 8 was used. As treated water, nickel complex waste water containing 500 mg / L in terms of nickel was prepared. This waste water was accommodated in the precipitation tank 2, sodium hydroxide was added to adjust the waste water to pH 9.8, and Ni ²⁺ in the waste water was precipitated as nickel hydroxide. Moreover, the filter aid was supplied from the filter aid tank 5 filled with the filter aid A to the mixing tank 6 and mixed with water to prepare a filter aid slurry. This was supplied to the solid-liquid separator 3, and a layer of filter aid having an average thickness of 1 mm was produced on the filter 33. After that, when water to be treated was supplied from the precipitation tank 2 to the solid-liquid separator 3 and filtered, it was confirmed that 99% or more of nickel in the filtrate (treated water) was recovered.

  The metals that can be reacted with hydroxide ions in water to form hydroxides using the method of the above embodiment, and the generated hydroxides settle in water to be separated and recovered as precipitates are listed below.

Cu, Cr, Ni, Zn, Al, Cd, Ga, Au, Ag, Co, Fe, Pb, Be, Mg, Mn
According to the above embodiment, no special reaction operation is required, and the fine metal compound particles precipitated in water can be directly solid-liquid separated.

1, 1A, 1B ... Metal recovery device, 2 ... Precipitation tank, 2A ... Mixed precipitation tank,
3, 3B ... solid-liquid separator, 31 ... introduction space, 32 ... discharge space,
33 ... filter,
4 ... separation tank, 5 ... filter aid tank, 6 ... mixing tank,
11: Filter aid (magnetic single particles), 12: Coating agent (polymer),
13 ... Filter aid (aggregates of magnetic particles),
P1-P9 ... pump, V1-V3 ... valve (three-way valve),
L2 ... treated water supply line, L3 ... treated water distribution line, L31 ... stripped water supply line, L32 ... treated water carry-out line, L33 ... treated water reuse line, L34 ... treated water reuse line,
L4 ... exfoliation discharge line, L5 ... filter aid return line, L6 ... filter aid supply line, L7 ... mixing line, L8 ... copper concentrated water discharge line,
L10 ... desalting line, L11 ... stripping water supply line.

Claims (8)

A precipitation tank for precipitating metal compound crystal particles from water to be treated containing metal ions;
A filter aid supply device for supplying a filter aid having an average particle size of 0.5 to 20 μm of single particles or aggregates containing a magnetic substance;
A mixing tank for mixing the filter aid and the dispersion medium supplied from the filter aid supply device;
The mixture supplied from the mixing tank is filtered, and the water to be treated supplied from the precipitation tank is filtered thereon to deposit the metal compound crystal particles in the water to be treated and the filter aid in the mixture. A solid-liquid separation device having a filter to form
A treated water supply line for supplying treated water from the precipitation tank to the solid-liquid separator,
A mixing line that is connected to the treated water supply line and joins the mixture from the mixing tank to the treated water;
A stripping water supply line that supplies stripping water on the filter for stripping and removing the deposited layer from the filter;
A separation tank for separating the metal compound crystal particles and the filter aid contained in the peeled material discharged together with the peeling water from the solid-liquid separation device;
A peeled material discharge line for discharging the peeled material from the solid-liquid separator to the separation tank;
A filter aid return line for returning the filter aid separated in the separation tank to the filter aid supply device;
A metal recovery apparatus comprising:   The filter aid comprises an aggregate obtained by aggregating magnetic particles whose surfaces are coated with a polymer, and the average particle diameter D1 of the magnetic particles is in the range of 0.5 to 20 μm, and the average aggregation of the aggregates 2. The apparatus according to claim 1, wherein the diameter D2 satisfies D1 <D2 ≦ 20 μm, and the average coating thickness t of the polymer satisfies 0.01 ≦ t ≦ 0.25 μm.   The apparatus further comprises a desalting line connected to an upper portion of the introduction space of the solid-liquid separator, and supplying tap water to the introduction space to remove ions contained in a deposited layer on the filter. Item 3. The device according to any one of Items 1 and 2.   The apparatus further comprises a stripping water line connected to a side portion of the introduction space of the solid-liquid separation device, supplying tap water from the side to the introduction space, and stripping and removing the deposited layer from the filter. The apparatus according to any one of claims 1 to 3. A single particle or agglomerate containing a magnetic substance is mixed with a filter aid having an average diameter of 0.5 to 20 μm and water to be treated containing metal ions, and the water to be treated is made alkaline to precipitate crystal particles of the metal compound. A mixed precipitation tank;
A filter aid supply device for supplying the filter aid to the mixed precipitation tank;
While filtering the to-be-treated water supplied from the said mixing precipitation tank, the mixture supplied from the said mixing precipitation tank is filtered, and the metal compound crystal particle in the to-be-processed water and the filter aid in the said mixture on it A solid-liquid separator having a filter for forming a deposited layer of
A treated water supply line for supplying treated water from the mixed precipitation tank to the solid-liquid separator,
A stripping water supply line that supplies stripping water on the filter for stripping and removing the deposited layer from the filter;
A separation tank for separating the metal compound and the filter aid contained in the peeled material discharged together with the peeling water from the solid-liquid separation device;
A peeled material discharge line for discharging the peeled material from the solid-liquid separator to the separation tank;
A filter aid return line for returning the filter aid separated in the separation tank to the filter aid supply device;
A metal recovery apparatus comprising:   The filter aid comprises an aggregate obtained by aggregating magnetic particles whose surfaces are coated with a polymer, and the average particle diameter D1 of the magnetic particles is in the range of 0.5 to 20 μm, and the average aggregation of the aggregates 6. The apparatus according to claim 5, wherein the diameter D2 satisfies D1 <D2 ≦ 20 μm, and the average coating thickness t of the polymer satisfies 0.01 ≦ t ≦ 0.25 μm. (A) precipitating metal compound crystal particles from water to be treated containing metal ions;
(B) A single particle or agglomerate containing a magnetic substance is mixed with a filter aid having an average diameter of 0.5 to 20 μm and the water to be treated;
(C) filtering the mixture with a filter of a solid-liquid separator to form a filter aid layer in which the filter aid is deposited on the filter;
(D) supplying the water to be treated onto the filter, allowing the water to be treated to permeate the filter aid layer, and capturing the metal compound crystal particles contained in the water to be treated by the filter aid;
(E) Supplying stripping water to the solid-liquid separator, stripping and removing the metal compound crystal particles together with the filter aid from above the filter with stripping water,
(F) separating and recovering the metal compound crystal particles from the filter aid removed and removed;
(G) A metal recovery method characterized by reusing the separated and recovered filter aid in the step (b). (I) precipitating metal compound crystal particles from water to be treated containing metal ions;
(Ii) A slurry liquid is prepared by mixing a filter aid having an average diameter of 0.5 to 20 μm with single particles or aggregates containing a magnetic substance and the water to be treated;
(Iii) filtering the slurry liquid through a filter of a solid-liquid separator, forming a filter aid / metal compound crystal particle mixed layer in which the filter aid and metal compound crystal particles are deposited on the filter;
(Iv) supplying stripping water to the solid-liquid separator, stripping and removing the metal compound crystal particles together with the filter aid from above the filter with stripping water,
(V) separating and recovering the metal compound crystal particles from the removed filter aid;
(Vi) A metal recovery method, wherein the separated and recovered filter aid is reused in the step (ii).

Images