Treatment method for tungsten-containing liquid and treatment device for tungsten-containing liquid

Abstract

A treatment method for a tungsten-containing liquid, including a flocculation treatment step for performing flocculation treatment of a tungsten-containing liquid with an inorganic flocculant and a solid-liquid separation step for performing solid-liquid separation of a flocculated sludge obtained in the flocculation treatment step, said treatment method being characterized in that the pH of water to be treated in the flocculation treatment step is adjusted to 5.5-6.4.

Description

Method for treating tungsten-containing liquid and apparatus for treating tungsten-containing liquid

[0001] The present invention relates to a method for treating a tungsten (W)-containing liquid and a treatment apparatus for a tungsten-containing liquid, and more specifically, to a method and apparatus for flocculating a tungsten-containing liquid with an inorganic flocculant and separating the resulting flocculated sludge into solid and liquid form.

[0002] Tungsten, a type of rare metal, is used in a wide range of industrial fields, including semiconductor applications such as sputtering targets, industrial machinery such as automobiles as cutting tools and wear-resistant tools, and chemical industries such as desulfurization and denitrification catalysts. Therefore, tungsten recycling is being considered.

[0003] Patent Document 1 describes a method for recovering tungsten from a tungsten-containing solution, which involves concentrating a rare metal ion-containing solution, such as tungsten, using a membrane, and then extracting the rare metal ions from the concentrated solution with an extractant.

[0004] Patent Document 2 describes a method for obtaining metallic tungsten by hydrogen reduction of tungstate in a tungstate-containing mineral, which is converted to tungsten oxide via alkali tungstate and ammonium tungstate. In this method, an aluminum compound is added to an aqueous solution of alkali tungstate to adsorb impurities in the alkali tungstate onto aluminum hydroxide and precipitate it, thereby purifying the alkali tungstate.

[0005] As a method for recovering tungsten from tungsten-containing materials, the method for recovering tungsten from superalloy scrap described in Non-Patent Document 1 has already been put into practical use.

[0006] Furthermore, Non-Patent Document 2 describes a method for removing tungsten from tungsten-containing liquids, which involves immobilizing the tungsten in tungsten-containing wastewater with an inorganic coagulant, followed by coagulation, sedimentation, and separation for removal. However, Non-Patent Document 2 only describes the removal of tungsten from tungsten-containing wastewater and does not disclose any method for treating the coagulated and settled sludge, nor any method for reusing the treated water as recovered water.

[0007] When treating tungsten-containing wastewater and using the treated water as recovered water, it is necessary to first coagulate the tungsten-containing wastewater, and then perform recovery treatments such as membrane separation and desalination in the treated water recovery process.

[0008] In other words, for example, the standard value for iron concentration in river discharge is less than 3 mg / L, but when treated water is used as recovered water, the required water quality varies depending on the water quality requirements of the destination, but a lower water quality than the river discharge standard is required, such as 0.02 to 0.1 mg / L or even lower.

[0009] However, in the coagulation treatment of tungsten-containing wastewater, iron-based inorganic coagulants such as ferric polysulfate and ferric chloride are usually used, making it easy for iron ions to leak into the treated water. As a result, the leaked iron places a heavy load on downstream solid-liquid separation equipment such as turbidity removal membranes and filters, and desalination equipment such as reverse osmosis (RO) membranes, causing problems such as blockages and leading to a deterioration of the water quality and recovery rate of the recovered water.

[0010] JP2023-55031A JP2023-107527A

[0011] "Commercialization of Tungsten Recycling from Carbide Alloy Scrap" (July 2016, SEI Technical Review, No. 189, pp. 9-14) "Removal of tungsten oxyanions from industrial wastewater by precipitation, coagulation, and flocculation processes" (Journal of Hazardous Materials, Vol. 148, Issue 3, 30 September 2007, Pages 613-615)

[0012] In view of the above-mentioned conventional situation, the present invention aims to provide a method for treating a tungsten-containing liquid and a treatment apparatus for a tungsten-containing liquid that treats the tungsten-containing liquid to recover tungsten as a valuable material, and when recovering the treated water, suppress the leakage of tungsten to efficiently recover tungsten as a valuable material, while also suppressing the leakage of metal components such as iron, thereby improving the water quality of the recovered water and improving the recovery rate.

[0013] As a result of repeated studies to solve the above problems, the inventors of the present invention have found that the above problems can be solved by adjusting the pH of the treated water to a predetermined pH during the coagulation treatment of a tungsten-containing liquid with an inorganic coagulant and then separating the solid and liquid.

[0014] In other words, the gist of this invention is as follows:

[0015] [1] A method for treating a tungsten-containing liquid, comprising a coagulation step of coagulating the tungsten-containing liquid with an inorganic coagulant, and a solid-liquid separation step of separating the coagulated sludge obtained in the coagulation step into solid and liquid form, characterized in that the pH of the water to be treated in the coagulation step is adjusted to 5.5 to 6.4.

[0016] [2] The method for treating a tungsten-containing liquid according to [1], characterized in that the pH of the water to be treated is adjusted to 5.8 to 6.4.

[0017] [3] The method for treating a tungsten-containing liquid according to [1] or [2], characterized in that the inorganic flocculant is one of aluminum sulfate, ferrous sulfate, polyferric sulfate, aluminum chloride, polyaluminum chloride, and ferric chloride.

[0018] [4] A method for treating a tungsten-containing liquid according to any one of [1] to [3], characterized in that it includes a pH adjustment step of adjusting the pH of the tungsten-containing liquid prior to the coagulation treatment step.

[0019] [5] A method for treating a tungsten-containing liquid according to any one of [1] to [4], characterized in that, in the coagulation treatment step, coagulation treatment is performed with the inorganic coagulant, followed by coagulation treatment with the polymer coagulant.

[0020] [6] A method for treating a tungsten-containing liquid according to any one of [1] to [5], further comprising a sludge return step of returning a portion of the separated sludge obtained in the solid-liquid separation step to the coagulation treatment step.

[0021] [7] A method for treating a tungsten-containing liquid according to any one of [1] to [6], comprising a filtration step of filtering the separated water obtained in the solid-liquid separation step and a reverse osmosis membrane separation step of filtering the filtered water obtained in the filtration step.

[0022] [8] A method for treating a tungsten-containing liquid according to any one of [1] to [7], wherein the tungsten concentration of the tungsten-containing liquid is 1 mg-W / L or more.

[0023] [9] A tungsten-containing liquid treatment apparatus comprising a flocculation treatment means for flocculating a tungsten-containing liquid with an inorganic flocculant, and a solid-liquid separation means for solid-liquid separation of the flocculated sludge obtained by the flocculation treatment means, characterized in that the apparatus has a pH adjustment means for adjusting the pH of the water to be treated in the flocculation treatment means to 5.5 to 6.4.

[0024]

[10] The apparatus for tungsten-containing liquid according to [9], characterized in that it has a sludge return means for returning a portion of the separated sludge obtained by the solid-liquid separation to the coagulation treatment means.

[0025]

[11] The apparatus for processing a tungsten-containing liquid according to [9] or

[10] , comprising a filtration means for filtering the separated water obtained by the solid-liquid separation means, and a reverse osmosis membrane separation means for filtering the filtered water obtained by the filtration means.

[0026] According to the present invention, in the treatment of a tungsten-containing liquid in which a tungsten-containing liquid is coagulated with an inorganic coagulant and the coagulated sludge is separated into solid and liquid form, by adjusting the pH of the treated water to a limited predetermined range, the leakage of tungsten into the coagulated water is suppressed, as is the leakage of metal components such as iron. Under the following effects, tungsten in the tungsten-containing liquid can be efficiently recovered as a W valuable material, and recovered water with good water quality can be obtained with a high recovery rate.

[0027] (1) By reducing the leakage of metal components such as tungsten and iron into the coagulated water, it is possible to improve the quality of wastewater recovery treatment water and stabilize subsequent treatment.

[0028] (2) By reducing the leakage of metal components such as tungsten and iron into the coagulated water, the water recovery rate can be improved and stabilized by stabilizing the wastewater recovery treatment.

[0029] (3) By reducing tungsten leakage into the coagulated water, the utilization of valuable materials can be promoted.

[0030] (4) Based on (1) to (3), it is possible to achieve stable operation of the entire factory and to significantly reduce operating costs such as energy costs.

[0031] Figure 1 is a flow chart showing one embodiment of the tungsten-containing liquid processing apparatus of the present invention. Figure 2 is a graph showing the relationship between the W concentration and total Fe concentration of the coagulated water in Experimental Examples 1 to 7 and the pH during coagulation treatment.

[0032] The following describes in detail embodiments of the method for treating tungsten-containing liquids and the apparatus for treating tungsten-containing liquids according to the present invention.

[0033] [Method for treating tungsten-containing liquid] The present invention relates to a method for treating tungsten-containing liquid, comprising a coagulation treatment step of coagulating the tungsten-containing liquid with an inorganic coagulant, and a solid-liquid separation step of separating the coagulated sludge obtained in the coagulation treatment step into solid and liquid form, characterized in that the pH of the water to be treated in the coagulation treatment step is adjusted to 5.5 to 6.4.

[0034] [Mechanism] According to the present invention, by adjusting the pH of the treated water to a limited pH range of 5.5 to 6.4 when a tungsten-containing liquid is treated with an inorganic coagulant, it is possible to suppress the leakage of tungsten into the treated water, as well as the leakage of metal components such as iron.

[0035] That is, as is clear from the results of Experimental Examples 1 to 7 described below, there is a correlation between the pH of the water to be treated when coagulating the tungsten-containing liquid with an inorganic coagulant and the W concentration and Fe concentration of the resulting coagulated treated water. The W concentration tends to increase as the pH increases, while the Fe concentration tends to decrease and then increase as the pH increases. If the pH is in the range of 5.5 to 6.4, preferably 5.8 to 6.4, both the leakage of W and Fe can be suppressed, and coagulated treated water with sufficiently reduced W concentration and Fe concentration can be obtained.

[0036] Therefore, in the present invention, the pH of the water to be treated (the water to be coagulated) during the coagulation treatment is adjusted to 5.5 to 6.4, preferably 5.8 to 6.4.

[0037] [Tungsten-containing liquid] As the tungsten-containing liquid, tungsten-containing wastewater is preferable. Examples of tungsten-containing wastewater include used tungsten catalyst-containing wastewater used in organic synthesis such as heavy oil refining, tungsten-containing wastewater used in NO removal in thermal power plants, tungsten-containing liquids obtained by an alkali extraction method or an alkali dissolution method in the recycling process of cemented carbide scrap, underground contaminated water and leachate in landfill sites, and wastewater discharged from electronic component manufacturing processes, etc., but are not limited thereto. Ｘ The tungsten concentration in the tungsten-containing wastewater to be treated in the present invention is usually 1 mg-W / L or more, for example, 1 to 3000 mg-W / L, particularly preferably about 20 to 500 mg-W / L, but is not limited thereto.

[0038] [Coagulation treatment step] In the coagulation treatment step, an inorganic coagulant is added to the above-mentioned tungsten-containing liquid for coagulation treatment. In the coagulation treatment step, after adding the inorganic coagulant, a polymer coagulant may be used to coarsen the flocs.

[0039]

[0040] ​<Inorganic Coagulant> As the inorganic coagulant used for the coagulation treatment of the tungsten-containing solution, salts such as aluminum and iron are suitable, and sulfates or chlorides are particularly preferred. Specifically, ferrous sulfate, ferrous sulfate monohydrate, polyferric sulfate, aluminum chloride, polyaluminum chloride, ferric chloride, etc. are preferred. Among these, in the present invention, from the viewpoint of the coagulation effect of tungsten, polyferric sulfate is particularly preferred.

[0041] The addition amount of the inorganic coagulant is appropriately determined according to the W concentration in the tungsten-containing solution and the type of the inorganic coagulant used. When the tungsten concentration of the tungsten-containing solution is about 20 to 500 mg / L, for example, it is preferably about 100 to 4000 mg / L as polyferric sulfate (total iron 11%).

[0042] <pH Adjustment> In the present invention, the pH is adjusted with a pH adjuster (acids such as hydrochloric acid and sulfuric acid, or alkalis such as sodium hydroxide) so that the pH of the water to be treated during the coagulation treatment with the inorganic coagulant is 5.5 to 6.4, preferably 5.8 to 6.4.

[0043] The lower the pH of the water to be treated during the coagulation treatment, the easier it is for metal components such as iron derived from the inorganic coagulant to leak. Therefore, the pH is 5.5 or higher, preferably 5.8 or higher. The leakage of iron decreases with the increase in pH. However, when the pH exceeds 6.4, iron is likely to leak again, and tungsten also starts to leak. This is because when the pH exceeds 6.4, tungsten exists in the form of WO ４ ２－ and the reactivity with the inorganic coagulant becomes low. If the pH is 6.4 or lower, tungsten exists in the form of W <​​​​​​Furthermore, since the pH of the tungsten-containing liquid used for coagulation treatment is often 4 or less, it is preferable to perform pH adjustment and coagulation treatment with an inorganic coagulant in separate processes in order to more effectively obtain the effects of pH adjustment. Accordingly, it is preferable to include a pH adjustment step before the coagulation treatment step with an inorganic coagulant, adjust the pH of the tungsten-containing liquid to about 4 to 5.5 in the pH adjustment step, and then adjust the pH as necessary in the coagulation treatment step to maintain a pH of 5.5 to 6.4, preferably 5.8 to 6.4. If the pH in this pH adjustment step exceeds 5.5, it becomes difficult to adjust the pH in the coagulation treatment step, so it is preferable that the adjusted pH value in the pH adjustment step is 5.5 or less.

[0045] <Polymer flocculants> After flocculation treatment with inorganic flocculants, further flocculation treatment can be performed by adding polymer flocculants. In this case, anionic polymer flocculants or nonionic polymer flocculants can be used as polymer flocculants, but generally, anionic polymer flocculants that are copolymers of acrylamide and acrylic acid or partial hydrolysates of polyacrylamide are preferred, and the amount added is preferably 0.1 to 20 mg / L, and particularly preferably about 1 to 10 mg / L.

[0046] [Solid-Liquid Separation Process] In the solid-liquid separation process, the flocculated sludge obtained in the flocculation process is separated into solid and liquid to obtain separated sludge. In this invention, for the following reasons, it is preferable to return a portion of the obtained separated sludge to the flocculation process, subject the remainder to dewatering treatment, and recover the separated water (flocculated water).

[0047] In other words, by returning a portion of the dewatered sludge to the coagulation process, the unreacted inorganic coagulant in the coagulation process reacts with the coagulated flocs of the returned sludge, promoting floc growth and increasing the floc diameter. As a result, tungsten in the tungsten-containing liquid can be efficiently recovered as a valuable material, and recovered water of good quality can be obtained with a high recovery rate.

[0048] If the pH of the return point for the separated sludge is low, the flocs will be destroyed by the redissolution of the sludge. However, if the return point for the separated sludge is a flocculation treatment process where the pH is adjusted to 5.5 to 6.4, preferably 5.8 to 6.4, then the redissolution of the returned sludge can be prevented, promoting floc growth and increasing the floc diameter.

[0049] [Dewatering Process] In the dewatering process, the remaining portion of the returned sludge obtained in the solid-liquid separation process is dewatered. It is preferable to use a filter press dewatering machine for this dewatering process because it can achieve a low moisture content.

[0050] The dewatered sludge obtained through this dewatering process is typically a highly concentrated sludge with a water content of 70% or less, and contains tungsten from the tungsten-containing liquid with a high recovery rate. Therefore, it can be reused in various fields as a valuable material.

[0051] [Wastewater Treatment Process] The dewatered filtrate obtained in the above dewatering process is of good water quality that meets the discharge standards and may be discharged as is. However, in order to recover it and reuse it for various water uses inside and outside the facility, a filtration process is provided in which it is filtered using an ultrafiltration (UF) membrane or a microfiltration (MF) membrane, and an RO membrane treatment process is provided in which the filtered water obtained in the filtration process is treated with a reverse osmosis (RO) membrane to remove salt.

[0052] The treated water obtained by filtering the dehydrated filtrate and then treating it with a reverse osmosis membrane has very good water quality and can therefore be recovered and effectively reused.

[0053] [Tungsten-containing liquid treatment apparatus] The present invention relates to a tungsten-containing liquid treatment apparatus comprising a flocculation treatment means for flocculating a tungsten-containing liquid with an inorganic flocculant, and a solid-liquid separation means for separating the flocculated sludge obtained by the flocculation treatment means into solid and liquid components, characterized in that it comprises a pH adjustment means for adjusting the pH of the water to be treated in the flocculation treatment means to 5.5 to 6.4.

[0054] Preferably, the tungsten-containing liquid processing apparatus of the present invention further includes a sludge return means for returning a portion of the separated sludge obtained by the solid-liquid separation means to a coagulation processing means, a filtration processing means for filtering the separated water obtained by the solid-liquid separation means, and a reverse osmosis membrane separation processing means for reverse osmosis membrane separation processing the filtered water obtained by the filtration processing means.

[0055] The tungsten-containing liquid processing apparatus of the present invention will be described more specifically below with reference to Figure 1, which shows one embodiment of the present invention. However, the tungsten-containing liquid processing apparatus of the present invention is not limited to the one shown in Figure 1.

[0056] In the tungsten-containing liquid treatment apparatus shown in Figure 1, the tungsten-containing liquid is supplied to the neutralization tank (pH adjustment tank) 2 via the raw water tank 1, and after its pH is adjusted to approximately 4 to 5.5 using a pH adjusting agent as described above, it is supplied to the reaction tank 3, where an inorganic coagulant is added for coagulation treatment. In the reaction tank 3, a pH adjusting agent is added as needed to adjust the pH to 5.5 to 6.4, preferably 5.8 to 6.4. The treated liquid from the reaction tank 3 is further treated in the coagulation tank 4 with the addition of a polymer coagulant, and the coagulated sludge with coarsely formed flocs is separated into solid and liquid in the sedimentation tank 5.

[0057] The separated water (sedimented water) from the sedimentation tank 5 is sent to the wastewater recovery facility 7 via the sedimentation treatment tank 6. The wastewater recovery facility 7 is equipment for reusing the sedimentation treatment water for various uses inside and outside the facility, and includes filtration devices such as ultrafiltration (UF) membranes and microfiltration (MF) membranes for removing suspended solids, and reverse osmosis (RO) membrane devices for desalination. The sedimentation treatment water may be discharged as is if it meets the discharge standards.

[0058] Meanwhile, a portion of the separated sludge from the sedimentation tank 5 is returned to the reaction tank 3, and the remainder is sent via the sludge storage tank 8 to the sludge dewatering machine 9 for dewatering treatment.

[0059] The sludge dewatering machine 9 is preferably a filter press dewatering machine, which efficiently dewaters the separated sludge.

[0060] The dewatered sludge obtained by the sludge dewatering machine 9 is fed to the W valuable material recovery facility 11 via the dewatered sludge storage tank 10, and further processed such as alkali melting and extraction, etc., and then reused as a W resource.

[0061] On the other hand, the dewatered filtrate obtained by the sludge dewatering machine 9 is fed to the wastewater treatment facility 13 via the dewatered filtrate storage tank 12. In the present invention, since the dewatered filtrate obtained by the sludge dewatering machine 9 has a low SS concentration and good water quality that meets the discharge standard value, the wastewater treatment facility 13 is not necessarily required, but discharge or advanced treatment is carried out according to the dissolved components.

[0062] The present invention will be described more specifically below by giving experimental examples in place of the examples.

[0063] [Test wastewater] As the test wastewater, the one prepared as follows was used.

[0064] Reagent-grade tungsten trioxide (WO ３ ) powder (particle size of about 0.01 - 0.05 μm) 89.7 g (50 g as W) and sodium tungstate (Na ２ WO ４ ·2H[[ID=1⑨ ２ O) 63.0 g (50 g as W) were put into 100 L of pure water and stirred to prepare an aqueous sodium tungstate solution in which tungsten trioxide powder was dispersed, and this was used as the test wastewater. Dissolved tungsten and undissolved tungsten coexist in the wastewater.

[0065] The total concentration of dissolved tungsten and undissolved tungsten in this test wastewater is 100 mg / L as W.

[0066] [Experimental Example 1] 300 mL of the above test wastewater was placed in a beaker, and after adjusting the pH to 5.4, 500 mg / L of ferric polysulfate (11% total iron) was added as an inorganic coagulant (sulfur equivalent concentration 39 mg-S / L). The mixture was rapidly stirred at 120 rpm for 5 min, and then slowly stirred at 40 rpm for 10 min. A pH adjuster was added to maintain the pH at 5.4 even after the addition of the ferric polysulfate. The supernatant water after coagulation was filtered using two layers of No. 5A filter paper, and the resulting filtrate was collected as the coagulated water. The total Fe concentration was analyzed by ICP emission spectrometry. The tungsten (W) concentration was analyzed by ICP emission spectrometry after adding a 4% choline solution and heating at 85°C for 10 minutes. The experiment was conducted at room temperature of 25°C.

[0067] [Experimental Examples 2-7] The same experiments as in Experimental Example 1 were conducted, except that the pH during the coagulation treatment was set as shown in Table 1.

[0068] [Results and Discussion] The analysis results of W concentration and total Fe concentration in experimental examples 1 to 7 are shown in Table 1 and Figure 2.

[0069]

[0070] From Table 1 and Figure 2, the following can be seen:

[0071] When coagulation treatment was performed at pH 5.4, 5.5, and 5.6, the W concentration in the treated water was 0 mg / L. On the other hand, the total Fe concentration decreased with increasing pH: 3.19 mg / L at pH 5.4, 1.50 mg / L at pH 5.5, and 1.01 mg / L at pH 5.6.

[0072] When coagulation treatment was performed at pH 6.4 and 6.5, the total Fe concentration in the treated water was 0.03 mg / L and 0.089 mg / L, and the W concentration was 0.54 mg / L and 1.08 mg / L, both increasing with increasing pH.

[0073] These results indicate that in order to keep the upper limit of the total Fe concentration below the discharge standard value of 3 mg / L and the W concentration below 1.0 mg / L, the pH needs to be between 5.5 and 6.4. To achieve a total Fe concentration of 0.5 mg / L or less, which is desirable for RO membrane water supply, the pH should preferably be between 5.8 and 6.4.

[0074] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible within the scope of achieving the effects of the invention. This application is based on Japanese Patent Application No. 2025-026939, filed on 21 February 2025, and Japanese Patent Application No. 2025-135891, filed on 18 August 2025, which are incorporated herein by reference in their entirety.

[0075] 1. Raw water tank 2. Neutralization tank 3. Reaction tank 4. Coagulation tank 5. Sedimentation tank 6. Sedimentation treatment tank 7. Wastewater recovery equipment 8. Sludge storage tank 9. Sludge dewatering machine 10. Dewatered sludge storage tank 11. W valuable material recovery equipment 12. Dewatered filtrate storage tank 13. Wastewater treatment equipment

Claims

1. A method for treating a tungsten-containing liquid, comprising a coagulation treatment step of coagulating the tungsten-containing liquid with an inorganic coagulant, and a solid-liquid separation step of separating the coagulated sludge obtained in the coagulation treatment step into solid and liquid form, characterized in that the pH of the water to be treated in the coagulation treatment step is adjusted to 5.5 to 6.

4.

2. The method for treating a tungsten-containing liquid according to claim 1, characterized in that the pH of the water to be treated is adjusted to 5.8 to 6.

4.

3. The method for treating a tungsten-containing liquid according to claim 1, characterized in that the inorganic flocculant is one of aluminum sulfate, ferrous sulfate, polyferric sulfate, aluminum chloride, polyaluminum chloride, and ferric chloride.

4. The method for treating a tungsten-containing liquid according to claim 1, characterized in that it includes a pH adjustment step for adjusting the pH of the tungsten-containing liquid prior to the coagulation treatment step.

5. The method for treating a tungsten-containing liquid according to claim 1, characterized in that, in the coagulation treatment step, coagulation treatment is performed with the inorganic coagulant, followed by coagulation treatment with the polymer coagulant.

6. The method for treating a tungsten-containing liquid according to claim 1, further comprising a sludge return step of returning a portion of the separated sludge obtained in the solid-liquid separation step to the coagulation treatment step.

7. A method for treating a tungsten-containing liquid according to claim 1, comprising a filtration step of filtering the separated water obtained in the solid-liquid separation step, and a reverse osmosis membrane separation step of subjecting the filtered water obtained in the filtration step to reverse osmosis membrane separation.

8. A method for treating a tungsten-containing liquid according to any one of claims 1 to 7, wherein the tungsten concentration of the tungsten-containing liquid is 1 mg-W / L or more.

9. A tungsten-containing liquid treatment apparatus comprising a coagulation treatment means for coagulating a tungsten-containing liquid with an inorganic coagulant, and a solid-liquid separation means for separating the coagulated sludge obtained by the coagulation treatment means into solid and liquid components, wherein the apparatus is characterized by having a pH adjustment means for adjusting the pH of the water to be treated in the coagulation treatment means to 5.5 to 6.

4.

10. The apparatus for tungsten-containing liquid according to claim 9, characterized in that it has a sludge return means for returning a portion of the separated sludge obtained by the solid-liquid separation means to the coagulation treatment means.

11. The apparatus for processing tungsten-containing liquid according to claim 9, comprising a filtration means for filtering the separated water obtained by the solid-liquid separation means, and a reverse osmosis membrane separation means for filtering the filtered water obtained by the filtration means.

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