Method for producing phosphoric acid-containing composition

Abstract

To provide a method for producing a phosphate-containing composition that can increase production efficiency.SOLUTION: Provided is a method for producing a phosphate-containing composition from an electroless nickel plating solution containing phosphoric acid compounds and organic matter. The method for producing the phosphate-containing composition includes: a separation step 60 of separating nickel ions by using a chelating resin from an electroless nickel plating solution with a pH of less than 7; and an electrolytic treatment step 62 of performing electrolytic treatment on the solution treated in the separation step 60 while maintaining a pH of less than 7. The method for producing the phosphate-containing composition includes a phosphate-containing composition acquisition step 64 of adding calcium hydroxide to the solution treated in the electrolysis step 62 to obtain a phosphate-containing composition containing calcium phosphate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a phosphoric acid-containing composition. [Background technology]

[0002] Patent Document 1 discloses a method for producing a phosphate-containing fertilizer solution.

[0003] In this manufacturing method, fine ozone bubbles are generated in the metal ion-removed plating waste solution in an oxidation tank to perform electrolytic oxidation, which promotes the oxidation of hypophosphite ions and phosphite ions contained in the metal ion-removed plating waste solution to produce orthophosphoric acid.

[0004] It is known that an oxidation reaction occurs in an alkaline solution, so it is conceivable to improve the efficiency of the electrolytic oxidation treatment by adding sodium hydroxide or the like to the metal ion removal plating waste solution to make it alkaline before performing the electrolytic oxidation treatment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-95108 Summary of the Invention [Problem to be solved by the invention]

[0006] In this production method, adding calcium hydroxide to the solution that has been electrolytically oxidized to obtain calcium phosphate promotes the formation of calcium carbonate, which is not the intended target. Therefore, in order to suppress the formation of calcium carbonate, it is necessary to perform a decarbonation treatment in which sulfuric acid or the like is added to the solution that has been electrolytically oxidized to lower the pH value and remove carbon dioxide.

[0007] On the other hand, if sulfuric acid is added to the solution until the pH value is lowered to a predetermined value or less in order to remove carbon dioxide, the amount of sodium sulfate produced by the reaction between sulfuric acid and sodium hydroxide increases, and the solution obtained after the decarbonation treatment contains a large amount of undesired sodium sulfate in addition to the intended calcium phosphate.

[0008] As a result, the content of calcium phosphate, which is the target of the obtained phosphate-containing composition, is reduced, resulting in a decrease in production efficiency.

[0009] The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a phosphoric acid-containing composition that can improve production efficiency. [Means for solving the problem]

[0010] One embodiment of the present invention relates to a method for producing a phosphate-containing composition from an electroless nickel plating solution containing a phosphate compound and an organic substance. This method includes a separation step of separating nickel ions from the electroless nickel plating solution having a pH of less than 7 using a chelating resin, and an electrolysis step of electrolyzing the solution treated in the separation step while maintaining the pH at less than 7. The method also includes a phosphate-containing composition obtaining step of adding calcium hydroxide to the solution treated in the electrolysis step to obtain the phosphate-containing composition containing calcium phosphate. In the electrolysis step, the solution treated in the separation step is treated with microbubbled ozone, and the boron-doped diamond electrode is used as an anode material for the electrolysis step. [Effects of the Invention]

[0011] According to this embodiment, in the separation step, by contacting the electroless nickel plating solution having a pH of less than 7 with a chelating resin, the nickel ions contained in the electroless nickel plating solution can be adsorbed onto the chelating resin by chelating action and separated.

[0012] Then, in the electrolysis step, the solution treated in the separation step is electrolyzed to convert the phosphoric acid compounds, hypophosphorous acid and / or phosphorous acid, into orthophosphoric acid.

[0013] At this time, in order to separate nickel ions using a chelating resin, the electrolytic treatment is carried out in a state in which the pH of the electroless nickel plating solution is maintained at less than 7. Therefore, in the electrolytic treatment step, a decarbonation treatment can be carried out simultaneously with the electrolytic treatment, in which carbon dioxide derived from organic acids contained in the electroless nickel plating solution is degassed as carbon dioxide gas.

[0014] In this way, an electroless nickel plating solution with a pH of less than 7 can be effectively used in both the adsorption treatment in which nickel ions are adsorbed by a chelating resin and the decarbonation treatment carried out in the electrolytic treatment step.

[0015] In addition, in the electrolysis treatment step, the electrolysis treatment is carried out without adjusting the pH value of the solution treated in the separation step so that it exceeds pH 7.

[0016] Therefore, compared to when the pH value of the electroless nickel plating solution is increased to make it alkaline before electrolytic oxidation treatment to promote the oxidation reaction, the addition of sodium hydroxide to the electroless nickel plating solution is unnecessary, which makes it possible to suppress the generation of sodium sulfate.

[0017] Next, in the phosphoric acid-containing composition obtaining step, calcium hydroxide is added to the solution treated in the electrolytic treatment step to obtain a phosphoric acid-containing composition containing calcium phosphate.

[0018] Here, the solution treated in the electrolytic treatment step has carbon dioxide removed as carbon dioxide gas in the decarbonation treatment, and therefore, even if calcium hydroxide is added to the solution treated in the electrolytic treatment step to obtain calcium phosphate in the phosphoric acid-containing composition obtaining step, the generation of calcium carbonate can be suppressed.

[0019] In this way, it is possible to suppress the production of calcium carbonate while suppressing the increase in sodium sulfate, and therefore the contents of calcium carbonate and sodium sulfate contained in the obtained phosphate-containing composition can be reduced.

[0020] Therefore, the content of the calcium phosphate to be obtained can be increased in the obtained phosphate-containing composition, which makes it possible to increase the production efficiency of the calcium phosphate to be obtained. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a flowchart showing an outline of the manufacturing process of a method for manufacturing a phosphate-containing composition according to one embodiment. [Figure 2] FIG. 2 is a flow chart showing the steps of treating an electroless nickel plating solution in which a method for producing a phosphoric acid-containing composition according to one embodiment is carried out. [Figure 3] FIG. 3 is an explanatory diagram of an electrolytic treatment device used in a method for producing a phosphoric acid-containing composition according to one embodiment. [Figure 4] FIG. 4 is a table summarizing the conditions for each process step in the nickel recovery process. [Figure 5] FIG. 5 is a table summarizing the conditions for each treatment step in the phosphoric acid recovery treatment. [Figure 6] FIG. 6 is a table summarizing the analysis results of the compositions of the phosphoric acid-containing compositions obtained in the examples and the phosphoric acid-containing compositions of the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0022] A method for producing a phosphoric acid-containing composition according to one embodiment of the present invention will be described below.

[0023] [[Method of manufacturing a phosphoric acid-containing composition]] <Summary> FIG. 1 is a flowchart showing an outline of the manufacturing process of a method for manufacturing a phosphate-containing composition according to one embodiment.

[0024] As shown in FIG. 1, in one embodiment of the method for producing a phosphoric acid-containing composition, a waste liquid recovery step 20, a nickel separation step 22, a nickel recovery step 24, a phosphoric acid-containing composition recovery step 26, and a purification step 28 are carried out.

[0025] (Recovery process) In the waste liquid recovery step 20, the used electroless nickel plating solution is recovered and stored.

[0026] The basic composition of the electroless nickel plating solution to be recovered is made up of metal salts such as nickel sulfate, reducing agents such as sodium hypophosphite, complexing agents such as sodium citrate, and trace amounts of additives such as bismuth and sulfur compounds. In addition, the electroless nickel plating solution to be recovered is lead-free, meaning that the additives do not contain harmful substances such as lead.

[0027] Specifically, the electroless nickel plating solution contains nickel sulfate (NiSO), hypophosphorous acid (HPO), phosphorous acid (HPO), carboxylic acids, and trace amounts of additives, such as citric acid (CHO), succinic acid (CHO), malic acid (CHO), and other organic acids.

[0028] The additives do not contain harmful substances such as lead (Pb), antimony (Sb), and cadmium (Cb).

[0029] (Nickel separation process) The nickel separation step 22 performs an ion exchange treatment on the electroless nickel plating solution recovered in the waste liquid recovery step 20. In this ion exchange treatment, a nickel adsorption / desorption treatment is performed in which nickel (Ni) is adsorbed and desorbed.

[0030] The nickel adsorption / desorption treatment uses a chelating resin, such as an H-type strongly acidic cation exchange chelating resin.

[0031] Specifically, the electroless nickel plating solution is supplied to a column packed with an H-type strongly acidic cation exchange chelating resin and passed through the column, whereby the nickel ions contained in the electroless nickel plating solution are adsorbed onto the H-type strongly acidic cation exchange chelating resin and removed from the electroless nickel plating solution (deionization process).

[0032] In this nickel separation process, the amount of nickel contained in the solution that has passed through the column is reduced to a standard value or less, so that the phosphorus valuables obtained from the solution that has passed through the column can be used as animal feed.

[0033] At this time, the flow rate of the electroless nickel plating solution, the permeation time, the washing conditions, etc. are adjusted so that the nickel concentration in the solution that has passed through the column is 10 ppm or less.

[0034] In this nickel separation step 22, the nickel adsorbed on the H-type strongly acidic cation exchange chelating resin is separated from the H-type strongly acidic cation exchange chelating resin, thereby regenerating the H-type strongly acidic cation exchange chelating resin (regeneration step).

[0035] Hydrochloric acid (HCl) is used as the desorbing agent, and the chemical reaction shown in (Equation 1) occurs.

[0036] (Formula 1) R.H. + +Ni 2+ ⇔ R·Ni 2+ +H + R.H. + : Chelate resin

[0037] (Nickel recovery process) In the nickel recovery step 24, nickel sludge generation and settling treatment is carried out.

[0038] In the nickel recovery step 24, sodium hydroxide (NaOH) is used as a neutralizing agent, and the chemical reaction shown in (Equation 2) occurs.

[0039] (Formula 2) 2NaOH + NiCl2 --> Ni(OH)2 + 2NaCl

[0040] Then, in the nickel recovery step 24, solid-liquid separation is carried out, and the separated solid component is dried, thereby recovering nickel as a valuable resource.

[0041] (Phosphoric acid-containing composition recovery step) In the phosphoric acid-containing composition recovery step 26, the solution treated in the nickel separation step 22 is subjected to an electrolytic oxidation treatment, which is an electrolytic treatment, and a chemical oxidation treatment using ozone treatment, and a phosphoric acid-containing composition is recovered from the solution treated in the nickel separation step 22.

[0042] Specifically, the solution treated in the nickel separation step 22 contains phosphorus compounds and organic matter. Sulfuric acid (H2SO4) is added to the solution treated in the nickel separation step 22 to adjust the pH value to between pH 1.5 and pH 1.7.

[0043] The pH-adjusted solution is then subjected to electrolytic oxidation using a boron-doped diamond electrode as the anode material, followed by chemical oxidation using microbubbled ozone injection, which has a strong oxidizing power. This decomposes the organic components in the pH-adjusted solution and converts hypophosphorous acid and / or phosphorous acid to orthophosphoric acid. This results in the chemical change shown in Equation 3.

[0044] (Formula 3) H3PO2 or H3PO3--> H3PO4

[0045] The ozone concentration, flow rate, and treatment time of the chemical oxidation treatment are adjusted so that the COD (chemical oxygen demand: an indicator of the amount of pollutants in water) derived from the complexing agent is 500 mg / L or less. Also, the current and treatment time of the electrolytic oxidation treatment are adjusted so that the concentration ratio of hypophosphorous acid to orthophosphoric acid is 4% or less.

[0046] In addition, various organic acids in the solution treated in the nickel separation step 22 are decomposed into carbon dioxide (CO2) and water (H2O), and the carbon dioxide (CO2) is degassed.

[0047] (purification process) In the purification step 28, calcium phosphate production and precipitation treatment is carried out, and a phosphate-containing composition having a water content of 20% or less is obtained from the solution treated in the phosphate-containing composition recovery step 26.

[0048] Specifically, in the purification step 28, an emulsion containing a suspension of calcium hydroxide (Ca(OH)2) fine powder is added to the solution treated in the phosphoric acid-containing composition recovery step 26. This adjusts the pH value of the solution treated in the phosphoric acid-containing composition recovery step 26 to a pH of 8.5 or higher and 9.0 or lower.

[0049] At this time, the chemical reaction shown in (Equation 4) occurs.

[0050] (Formula 4) 3Ca(OH)2+2H3PO4--> Ca3(PO2)2+6H2O

[0051] The solution to which the emulsion has been added is stirred for at least 5 hours, and then allowed to stand for at least 8 hours to obtain a precipitate whose main component is calcium phosphate.

[0052] Here, calcium phosphate is a general term for salts consisting of calcium ions and phosphate or diphosphate ions. There are several compounds that are collectively called calcium phosphate, and each compound has a different ratio of Ca ions to PO 4 ions.

[0053] Next, the obtained precipitate is subjected to solid-liquid separation and drying to obtain a phosphoric acid-containing composition containing calcium phosphate as a main component.

[0054] Specifically, the obtained precipitate is subjected to solid-liquid separation using a centrifugal separator, and then dried and recovered on a heated drum, thereby obtaining a phosphate-containing composition as a solid, which is mainly composed of powdery or flaky calcium phosphate with a moisture content of 20% or less.

[0055] Here, as a solid-liquid separation treatment, a method using an apparatus such as a filter press, a screw press, a roller press, a belt press, etc. When using these apparatuses, the water content of the phosphoric acid-containing composition obtained after dehydration is 70% or more and 80% or less.

[0056] Phosphate-containing compositions with such moisture contents may develop toxic molds during the summer, etc. Therefore, such compositions cannot be used as feed. Furthermore, such compositions have a loose clay-like consistency, which can cause problems during blending and other processes when used as feed.

[0057] Therefore, in this embodiment, the obtained precipitate is subjected to solid-liquid separation, and then heated and dried to obtain a phosphoric acid-containing composition having a moisture content of 20% or less, which can be used as a raw material for feed or fertilizer.

[0058] <Operation Procedure> 2 is a flowchart showing the steps of treating an electroless nickel plating solution in which a method for producing a phosphoric acid-containing composition according to one embodiment is carried out. The procedure for treating an electroless nickel plating solution will be described with reference to FIG. 2.

[0059] First, used electroless nickel plating solution (Ni-P based electroless Ni plating waste liquid) collected from a factory or the like is stored in a waste liquid tank (Step A1). The electroless nickel plating solution to be collected is a Ni-P based electroless nickel plating solution, and is a lead-free type that does not contain harmful substances such as lead.

[0060] (separation process) This electroless nickel plating solution is supplied to an ion exchange treatment device for separation treatment (Step A2: nickel separation step 22). Hydrochloric acid and water are added as desorbing agents.

[0061] In this ion exchange treatment device, the electroless nickel plating solution is fed into a column packed with H-type strongly acidic cation exchange chelating resin and passed through the column, whereby the nickel ions contained in the electroless nickel plating solution are adsorbed onto the H-type strongly acidic cation exchange chelating resin and separated.

[0062] The solution that has passed through the column is then subjected to phosphoric acid recovery treatment, and the H-type strongly acidic cation exchange chelating resin that has adsorbed nickel ions is then subjected to nickel recovery treatment.

[0063] The washing water used in this nickel separation step 22 is treated in an existing wastewater treatment device (step B1) and then discharged into a river or the like.

[0064] [Nickel recovery processing] The H-type strongly acidic cation exchange chelating resin that has adsorbed nickel ions is added with hydrochloric acid and water as a desorbing agent to separate the nickel ions from the H-type strongly acidic cation exchange chelating resin, and the resulting solution is an aqueous solution of nickel chloride, which is then placed in a nickel release solution tank (step A3).

[0065] The aqueous nickel chloride solution from which the nickel ions have been separated is then sent to a nickel hydroxide production settling treatment tank, where sodium hydroxide is added as a neutralizing agent to produce nickel hydroxide (step A4).

[0066] The supernatant liquid from the nickel hydroxide production sedimentation treatment tank is treated in an existing wastewater treatment device (step B1) and then discharged into a river or the like.

[0067] The nickel sludge settled in the nickel hydroxide production settling treatment tank contains nickel hydroxide. This nickel sludge is treated in a nickel hydroxide solid-liquid separation treatment device, and nickel hydroxide containing nickel is obtained as a valuable resource (step A6). An example of the solid-liquid separation device is a dry separator.

[0068] The solution separated in the nickel hydroxide solid-liquid separation treatment device is sent to a circulation tank (step A7) and then returned to the nickel hydroxide production sedimentation treatment tank.

[0069] [Phosphate recovery process] The solution that has passed through the column in the nickel separation step 22 is stored in a phosphorus waste liquid tank (step C1) and then sent to an electrolytic treatment device.

[0070] (Electrolytic treatment equipment) Here, the electrolytic treatment device will be described.

[0071] FIG. 3 is an explanatory diagram of an electrolytic treatment device 10 used in a method for producing a phosphoric acid-containing composition according to one embodiment.

[0072] As shown in FIG. 3, the electrolytic treatment device 10 constituting the oxidation treatment device includes a treatment tank 30 that contains the solution treated in the nickel separation process 22, an electrolysis device 32 that performs electrolysis treatment S1 on the solution in the treatment tank 30, and an ozone device 34 that performs ozone treatment S2 on the solution in the treatment tank 30.

[0073] The electrolysis device 32 includes a rectifier 40 that outputs a DC voltage, an anode plate 42 that applies the positive electrode from the rectifier 40 to the solution in the treatment tank 30, and a cathode plate 44 that applies the negative electrode from the rectifier 40 to the solution in the treatment tank 30. The electrolysis device 32 electrolytically oxidizes the solution in the treatment tank 30 by applying a voltage between the anode plate 42 and the cathode plate 44 as the electrolysis treatment S1.

[0074] The anode material constituting the anode plate 42 is made of a boron-doped diamond electrode. The boron-doped diamond electrode is a P-type semiconductor formed by adding boron as a dopant (impurity) to diamond, which is an insulator, and its conductivity is adjusted by the amount of boron added.

[0075] The ozone device 34 includes an ozonizer 46 that generates ozone gas, and a circulation path 50 having a pump 48 that circulates the solution at the bottom of the treatment tank 30 to the top of the treatment tank 30. The ozone device 34 also includes a microbubble generator 54 that mixes the ozone gas supplied from the ozonizer 46 to the circulation path 50 with the solution, and supplies the ozone gas mixed with the solution as microbubbles 52 to the treatment tank 30.

[0076] Here, the microbubbles 52 refer to small bubbles having a diameter of 1 μm or more and less than 100 μm, and in this embodiment, small bubbles having a diameter of 1 μm or more and less than 50 μm are used.

[0077] The ozone device 34 performs an ozone treatment (S2) on the solution in the treatment tank 30 using the microbubbles 52 supplied to the treatment tank 30.

[0078] In this way, the oxidation reaction proceeds by simultaneously carrying out the electrolysis treatment S1 and the ozone treatment S2.

[0079] (Electrolytic treatment process) As shown in FIG. 2, in the electrolytic treatment device 10, sulfuric acid is added to the delivered solution while maintaining the pH of the solution at less than 7 (for example, about pH 3) to adjust the pH value to between pH 1.5 and pH 1.7.

[0080] Then, in the electrolytic treatment device 10, the sent solution is subjected to electrolytic oxidation treatment, which is electrolytic treatment S1, and at the same time, microbubbled ozone is injected to perform chemical oxidation treatment, which is ozone treatment S2 (step C2: electrolytic treatment process 62).

[0081] This converts hypophosphorous acid and / or phosphorous acid in the solution treated in the nickel separation step 22 into orthophosphoric acid. In addition, organic components in the solution treated in the nickel separation step 22 are decomposed into carbon dioxide and water, and the carbon dioxide is degassed.

[0082] The solution treated in the electrolysis process 62 is stored in an oxidation treatment phosphorus waste liquid tank (step C3), and then sent to a calcium phosphate production treatment tank.

[0083] <Step of obtaining phosphoric acid-containing composition> (stirring process) In the calcium phosphate production treatment tank, an emulsion containing suspended calcium hydroxide (slaked lime) powder is added and stirred with a stirring device so that the pH value of the stored solution becomes pH 8.5 or higher and pH 9.0 or lower (Step C4: Stirring step 66 of phosphoric acid-containing composition obtaining step 64).

[0084] The supernatant liquid from the calcium phosphate production treatment tank is treated in an existing wastewater treatment device (step B1) and then discharged into a river or the like.

[0085] (Precipitate Obtaining Process) The stirred solution is then transferred to a calcium phosphate settling tank and allowed to stand, allowing the phosphate-containing composition containing calcium phosphate to settle, thereby obtaining a precipitate, phosphate sludge (Step C5: precipitate obtaining step 68 of phosphate-containing composition obtaining step 64).

[0086] The supernatant liquid from the calcium phosphate settling tank is treated in an existing wastewater treatment device (step B1) and then discharged into a river or the like.

[0087] (Dehydration process) Next, the phosphate sludge settled in the calcium phosphate settling tank is subjected to solid-liquid separation and drying in a calcium phosphate solid-liquid separation treatment device. The water content of the phosphate sludge is reduced by the solid-liquid separation and drying treatment, and a phosphate-containing composition containing calcium phosphate is obtained as a valuable resource (Step C6: dehydration step 70).

[0088] As a result, a powdery or scaly phosphate-containing composition having a moisture content of 20% or less is obtained as a phosphorus valuable material.

[0089] The solution separated in the solid-liquid separation treatment device is sent to a circulation tank (step C7) and then returned to the calcium phosphate precipitation treatment tank.

[0090] (Action and effect) Next, the effects of this embodiment will be described.

[0091] The method for producing a phosphate-containing composition according to this embodiment is a method for producing a phosphate-containing composition from an electroless nickel plating solution containing a phosphate compound and an organic substance. The method for producing a phosphate-containing composition includes a nickel separation step 22 in which nickel ions are separated from an electroless nickel plating solution having a pH of less than 7 using a chelating resin. The method for producing a phosphate-containing composition includes an electrolysis treatment step 62 in which the solution treated in the nickel separation step 22 is electrolyzed while maintaining the pH at less than 7. The method for producing a phosphate-containing composition includes a phosphate-containing composition acquisition step 64 in which calcium hydroxide is added to the solution treated in the electrolysis treatment step 62 to obtain a phosphate-containing composition containing calcium phosphate.

[0092] According to this manufacturing method, in the nickel separation step 22, the electroless nickel plating solution having a pH of less than 7 is brought into contact with a chelating resin, and the nickel ions contained in the electroless nickel plating solution are adsorbed onto the chelating resin by chelating action and separated.

[0093] This makes it possible to reduce the amount of residual nickel ions remaining in the solution compared to when nickel ions are adsorbed using a general ion exchange resin.

[0094] Then, in the electrolysis step 62, the solution treated in the nickel separation step 22 is electrolyzed to convert the phosphoric acid compounds, hypophosphorous acid and / or phosphorous acid, into orthophosphoric acid.

[0095] At this time, the electrolytic treatment is carried out in a state where the pH of the electroless nickel plating solution is maintained below 7 in order to separate nickel ions using a chelating resin.

[0096] Therefore, in the electrolysis treatment step 62, a decarbonation treatment for removing carbon dioxide derived from organic acids contained in the electroless nickel plating solution as carbon dioxide gas can be carried out simultaneously with the electrolysis treatment S1.

[0097] Here, we will explain the decarbonation process. The electroless nickel plating solution that has undergone oxidation treatment contains a large amount of carbon dioxide derived from various organic acids that are components of the plating solution. When the pH value of the electroless nickel plating solution is high, the equilibrium reaction shifts toward ionic species. On the other hand, when the pH value of the electroless nickel plating solution is low, the equilibrium reaction shifts toward carbon dioxide gas.

[0098] Therefore, by lowering the pH value of the electroless nickel plating solution and shifting the equilibrium reaction toward carbon dioxide, the carbon dioxide derived from various organic acids in the electroless nickel plating solution can be released into the atmosphere as carbon dioxide.

[0099] In this way, the electroless nickel plating solution with a pH of less than 7 can be effectively used in both the nickel separation step 22, in which nickel ions are adsorbed and separated by a chelating resin, and the decarbonation treatment carried out in the electrolytic treatment step 62.

[0100] In the electrolysis step 62, the electrolysis step S1 is carried out without adjusting the pH value of the solution treated in the nickel separation step 22 so that it exceeds pH7.

[0101] Therefore, compared to when the pH value of the electroless nickel plating solution is increased to make it alkaline before electrolytic oxidation treatment to promote the oxidation reaction, the addition of sodium hydroxide to the electroless nickel plating solution is unnecessary, which makes it possible to suppress the generation of sodium sulfate.

[0102] Next, in the phosphoric acid-containing composition obtaining step 64, calcium hydroxide is added to the solution treated in the electrolytic treatment step 62 to obtain a phosphoric acid-containing composition containing calcium phosphate.

[0103] Here, the solution treated in the electrolysis treatment step 62 has carbon dioxide removed as carbon dioxide gas in the decarbonation treatment. Therefore, even if calcium hydroxide is added to the solution treated in the electrolysis treatment step 62 to obtain calcium phosphate in the phosphoric acid-containing composition obtaining step 64, the generation of calcium carbonate can be suppressed.

[0104] In this way, it is possible to suppress the production of calcium carbonate while suppressing the increase in sodium sulfate, and therefore the contents of calcium carbonate and sodium sulfate contained in the obtained phosphate-containing composition can be reduced.

[0105] Therefore, the content of the calcium phosphate to be obtained can be increased in the obtained phosphate-containing composition, which makes it possible to increase the production efficiency of the calcium phosphate to be obtained.

[0106] In addition, in the method for producing a phosphoric acid-containing composition of this embodiment, the electrolytic treatment step 62 involves performing an ozone treatment S2 on the solution treated in the nickel separation step 22 using microbubbled ozone, and also performing an electrolytic treatment S1 using a boron-doped diamond electrode as the anode material.

[0107] Here, for example, if lead dioxide is used as the anode material in the electrolysis process 62, lead eluted from the anode material may be mixed into the electrolytically treated solution. Also, if platinum or high-density carbon is used as the anode material, the decomposition efficiency and durability of organic matter are inferior, making it difficult to carry out the treatment efficiently and at low cost.

[0108] In contrast, the configuration of this embodiment can increase the efficiency of decomposing organic matter and improve the durability of the anode material, thereby enabling the electrolytic treatment S1 to be performed efficiently and at low cost.

[0109] In the method for producing a phosphoric acid-containing composition of this embodiment, the phosphoric acid-containing composition obtaining step 64 includes a stirring step 66 in which calcium hydroxide is added to the solution treated in the electrolytic treatment step 62 and the solution is stirred. The phosphoric acid-containing composition obtaining step 64 also includes a precipitate obtaining step 68 in which the solution treated in the stirring step 66 is allowed to stand to obtain a precipitate containing calcium phosphate.

[0110] According to the configuration of this embodiment, calcium hydroxide is added to the solution treated in the electrolytic treatment step 62 and stirred, thereby accelerating the production of calcium phosphate.

[0111] Furthermore, by leaving the stirred solution to stand and collecting the precipitate, the efficiency of obtaining calcium phosphate can be increased.

[0112] The method for producing a phosphoric acid-containing composition of this embodiment further includes a dehydration step 70 for reducing the water content of the precipitate obtained in the precipitate obtaining step 68 to obtain a phosphoric acid-containing composition.

[0113] According to the configuration of this embodiment, the water content of the obtained phosphoric acid-containing composition can be reduced, thereby suppressing mold growth in the obtained phosphoric acid-containing composition.

[0114] Here, we will explain mycotoxins. Mycotoxins, typified by aflatoxins, are known to be carcinogenic. Furthermore, mycotoxins are known to be passed through the bodies of livestock and end up in milk, etc., and strict control standards have been set for feed manufacturers under the jurisdiction of the Ministry of Agriculture, Forestry and Fisheries.

[0115] Therefore, when the obtained phosphate-containing composition is used as feed or a feed compounding agent, it is necessary to suppress the growth of mold, and in order to suppress the growth of mold, it is effective to reduce the moisture content of the obtained phosphate-containing composition.

[0116] The phosphate-containing composition obtained by the method for producing a phosphate-containing composition of the present embodiment can suppress mold growth by reducing the moisture content, and therefore can be used as a feed or a feed compounding agent.

[0117] Furthermore, as described above, the content of the calcium phosphate to be obtained can be increased in the obtained phosphate-containing composition, and therefore the total amount of the phosphate-containing composition required to obtain a predetermined amount of calcium phosphate can be reduced.

[0118] Therefore, compared to when the total amount of the phosphate-containing composition is increased in order to obtain a predetermined amount of calcium phosphate, dehydration treatments such as solid-liquid separation treatment and drying treatment can be carried out efficiently without reducing the treatment efficiency.

[0119] In the method for producing the phosphoric acid-containing composition of this embodiment, the stirring step 66 includes adding an emulsion in which calcium hydroxide powder is suspended.

[0120] According to the configuration of this embodiment, the mixing operation of calcium hydroxide into the solution in the stirring step 66 is easier than when calcium hydroxide powder is directly added.

[0121] Furthermore, in the method for producing the phosphoric acid-containing composition of this embodiment, the electroless nickel plating solution used in the nickel separation step 22 does not contain lead.

[0122] According to the configuration of this embodiment, a phosphate-containing composition suitable for use as a feed or a feed compounding agent can be obtained.

[0123] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Example]

[0124] The method for producing a phosphoric acid-containing composition according to the embodiment described above was used to treat an electroless nickel plating solution containing a phosphoric acid compound and an organic substance, and the composition of the obtained phosphoric acid-containing composition was measured. The production method and the measurement results will be described below.

[0125] Figure 4 is a table showing the conditions for each process step in the nickel recovery process. Figure 5 is a table showing the conditions for each process step in the phosphoric acid recovery process.

[0126] [Production of Phosphate-Containing Compositions According to Examples] A method for producing a phosphoric acid-containing composition according to an embodiment will be described.

[0127] 2 and 4, the treatment (step A2) performed in the ion exchange treatment device includes a deionization step 80 and a regeneration step 82. The electroless nickel plating solution to be treated and the adsorption capacity of the adsorption device (a column filled with a chelating resin) used in the ion exchange treatment are indicated by a first condition 100.

[0128] In the deionization step 80, in accordance with the second condition 102, the electroless nickel plating solution was passed through a column (adsorption device) packed with H-type strongly acidic cation exchange chelating resin, and the nickel ions were adsorbed onto the H-type strongly acidic cation exchange chelating resin.

[0129] In the regeneration step 82, the H-type strong acid cation exchange chelating resin with adsorbed nickel ions was treated according to the third condition 104.

[0130] In the treatment in the nickel hydroxide production and precipitation treatment device (step A4), the neutralizing agent 84 based on the fourth condition 106 was used, and each treatment was carried out in accordance with the fourth condition 106.

[0131] The treatment carried out in the nickel hydroxide solid-liquid separation treatment device (step A6) was carried out in accordance with the fifth condition 108.

[0132] As shown in FIGS. 2 and 5, the treatment (step C2) performed in the oxidation treatment device includes an electrolytic treatment S1 and an ozone treatment S2, and each treatment was performed in accordance with the sixth condition 110.

[0133] In the calcium phosphate production treatment tank (step C4), calcium phosphate production treatment was carried out, and in the comparative example, decarbonation treatment was additionally carried out. These treatments were carried out in accordance with the seventh condition 112.

[0134] The treatment carried out in the calcium phosphate precipitation tank (step C5) was carried out in accordance with the eighth condition 114, and the treatment carried out in the calcium phosphate solid-liquid separation treatment device (step C6) was carried out in accordance with the ninth condition 116.

[0135] [Production of a Phosphate-Containing Composition According to a Comparative Example] The method for producing a phosphoric acid-containing composition according to the comparative example will be described only in terms of the differences from the method for producing a phosphoric acid-containing composition according to the example.

[0136] The method for producing a phosphoric acid-containing composition according to the comparative example and the method for producing a phosphoric acid-containing composition according to the example are significantly different in the treatment in the electrolytic treatment step 62 and the treatment in the stirring step 66 .

[0137] In the comparative example of the method for producing a phosphoric acid-containing composition, in the electrolytic treatment S1 of the electrolytic treatment step 62, sodium hydroxide is added so that the pH value of the solution treated in the nickel separation step 22 is between pH 9.0 and pH 9.5 (see sixth condition 110).

[0138] Furthermore, in the comparative example of the method for producing a phosphoric acid-containing composition, sulfuric acid is added in the decarbonation treatment S5 of the stirring step 66 so that the pH value of the solution treated in the electrolytic treatment step 62 is between pH 2.0 and pH 2.5 (see seventh condition 112).

[0139] On the other hand, in the method for producing a phosphate-containing composition according to the embodiment, decarbonation treatment was actively carried out in the treatment in the oxidation treatment device (step C2), but decarbonation treatment was not actively carried out in the treatment in the calcium phosphate production treatment tank (step C4).

[0140] [evaluation] FIG. 6 is a table summarizing the analytical results of the compositions of the phosphoric acid-containing compositions obtained in the Examples and the phosphoric acid-containing compositions of the Comparative Examples, and FIG. 6 shows the analytical method for each composition.

[0141] 6, the phosphate-containing composition obtained by the method for producing a phosphate-containing composition according to the Example has a lower content of calcium sulfate and sodium sulfate than the phosphate-containing composition obtained by the method for producing a phosphate-containing composition according to the Comparative Example. It was also confirmed that the phosphate-containing composition obtained by the method for producing a phosphate-containing composition according to the Example has a higher content of the target tricalcium phosphate than the phosphate-containing composition obtained by the method for producing a phosphate-containing composition according to the Comparative Example.

[0142] Therefore, the phosphate-containing composition obtained by the method for producing a phosphate-containing composition according to the example was able to increase the content of calcium phosphate, which was the target of production, and was able to increase the production efficiency of calcium phosphate, which was the target of production. [Explanation of symbols]

[0143] 10 Electrolytic treatment equipment 22 Separation process 44 cathode plate 52 Microbubbles 62 Electrolytic treatment process 64 Phosphate-containing composition obtaining step 66 Stirring process 68 Precipitate acquisition process 70 Dehydration process S1 Electrolytic treatment S2 Ozone Treatment S5 Decarboxylation

Claims

1. A method for producing a phosphoric acid-containing composition from an electroless nickel plating solution containing a phosphoric acid compound and an organic substance, comprising: a separation step of separating nickel ions from the electroless nickel plating solution having a pH of less than 7 using a chelating resin; an electrolysis treatment step in which the solution treated in the separation step is electrolyzed while maintaining the pH at less than 7; a phosphoric acid-containing composition obtaining step of adding calcium hydroxide to the solution treated in the electrolytic treatment step to obtain the phosphoric acid-containing composition containing calcium phosphate; Including, The electrolysis step involves ozone treatment of the solution treated in the separation step with microbubbled ozone, and electrolysis using a boron-doped diamond electrode as an anode material. A method for producing a phosphoric acid-containing composition.

2. A method for producing the phosphoric acid-containing composition according to claim 1, comprising: The phosphoric acid-containing composition obtaining step includes: a stirring step of adding the calcium hydroxide to the solution treated in the electrolytic treatment step and stirring the solution; a precipitate obtaining step of allowing the solution treated in the stirring step to stand and obtaining a precipitate containing the calcium phosphate; Including, A method for producing a phosphoric acid-containing composition.

3. A method for producing the phosphoric acid-containing composition according to claim 2, comprising: The method further comprises a dehydration step of reducing the water content of the precipitate obtained in the precipitate obtaining step to obtain the phosphoric acid-containing composition. A method for producing a phosphoric acid-containing composition.

4. A method for producing the phosphoric acid-containing composition according to claim 2 or 3, comprising: The stirring step includes adding an emulsion in which calcium hydroxide powder is suspended. A method for producing a phosphoric acid-containing composition.

5. A method for producing the phosphoric acid-containing composition according to any one of claims 1 to 4, comprising: The electroless nickel plating solution treated in the separation step is lead-free. A method for producing a phosphoric acid-containing composition.

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