Tantalum-niobium acid wastewater resourceful treatment method

Abstract

The invention belongs to the technical field of wastewater treatment and recycling, and particularly relates to a tantalum-niobium acid wastewater recycling treatment method. The invention provides a tantalum-niobium acid wastewater resourceful treatment method which comprises the following steps: mixing tantalum-niobium acid wastewater and a potassium salt aqueous solution for crystallization reaction, and carrying out solid-liquid separation to obtain a potassium fluosilicate crystal product and a potassium fluosilicate mother solution; and washing the potassium fluosilicate crystallization product with water to obtain potassium fluosilicate. According to the method provided by the invention, firstly, the tantalum-niobium acid wastewater is treated with the potassium salt aqueous solution, the fluorine resource in the tantalum-niobium acid wastewater is recovered in the form of potassium fluosilicate, and more than 80% of the fluorine resource in the tantalum-niobium acid wastewater can be effectively recovered.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment and resource utilization, and specifically relates to a method for resource utilization treatment of tantalum-niobium acid wastewater. Background Art

[0002] At present, hydrofluoric acid-sulfuric acid system is generally used to decompose ore in the process of tantalum-niobium hydrometallurgy. Therefore, a large amount of acidic silicon-containing wastewater, namely tantalum-niobium acid wastewater, is generated in the production process. Tantalum-niobium acid wastewater is mainly the water phase after tantalum-niobium ore is decomposed and extracted by industrial hydrofluoric acid and sulfuric acid. Its main components are hydrofluoric acid, sulfuric acid, fluorosilicic acid, fluorotitanic acid, fluorine complex iron and silicon tetrafluoride, etc., and its composition is very complex.

[0003] In the related art, the treatment method of tantalum-niobium acid wastewater usually adopts lime neutralization precipitation method. However, when tantalum-niobium acid wastewater is neutralized with lime, on the one hand, a large amount of solid waste residue will be generated, resulting in more and more waste residue and greatly increased treatment costs; on the other hand, the resources in the wastewater are not effectively utilized, resulting in a large amount of resource waste. Summary of the invention

[0004] The purpose of the present invention is to provide a method for resource recovery of tantalum-niobium acid wastewater. The method provided by the present invention recovers fluorine resources in tantalum-niobium acid wastewater in the form of potassium fluorosilicate, and can effectively recover more than 80% of the fluorine resources in tantalum-niobium acid wastewater.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0007] The tantalum-niobium acid wastewater and the potassium salt aqueous solution are mixed to carry out a crystallization reaction, and after solid-liquid separation, a potassium fluorosilicate crystal product and a potassium fluorosilicate mother liquor are obtained;

[0008] The potassium fluorosilicate crystal product is washed with water to obtain potassium fluorosilicate.

[0009] Preferably, the potassium salt aqueous solution is a potassium chloride aqueous solution.

[0010] Preferably, the mass concentration of potassium salt in the potassium salt aqueous solution is 200-300 g / L.

[0011] Preferably, when the tantalum-niobium acid wastewater and the potassium salt aqueous solution are mixed, the reaction excess coefficient of the potassium salt in the potassium salt aqueous solution is 1 to 1.5.

[0012] Preferably, the tantalum-niobium acidic wastewater contains Si and F elements, the mass concentration of the Si element is 25-35 g / L, and the mass concentration of the F element is 110-155 g / L.

[0013] Preferably, the temperature of the crystallization reaction is room temperature and the pressure is normal pressure.

[0014] Preferably, the mixing is: adding the potassium salt aqueous solution into the tantalum-niobium acid wastewater; the mixing is carried out under stirring, the stirring speed is 50 to 200 rpm, and the addition time of the potassium salt aqueous solution is 20 to 40 minutes.

[0015] Preferably, after the potassium salt aqueous solution is added, a crystallization mixed solution is obtained; and the method further comprises: subjecting the crystallization mixed solution to continuous crystallization reaction under standing conditions, wherein the standing time is 0.5 to 3 hours.

[0016] Preferably, the water washing further produces washing water, and the pH value of the washing water is 4 to 5;

[0017] The method also includes: using the wash water to prepare a potassium salt aqueous solution.

[0018] Preferably, the method further comprises: subjecting the potassium fluorosilicate mother liquor to resource processing to recover other valuable metals.

[0019] The present invention provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps: mixing tantalum-niobium acid wastewater and potassium salt aqueous solution for crystallization reaction, obtaining potassium fluorosilicate crystal product and silicon removal liquid after solid-liquid separation; washing the potassium fluorosilicate crystal product to obtain potassium fluorosilicate. The method provided by the present invention first uses potassium salt aqueous solution to treat tantalum-niobium acid wastewater, recovers fluorine resources in the tantalum-niobium acid wastewater in the form of potassium fluorosilicate, and can effectively recover more than 80% of fluorine resources in the tantalum-niobium acid wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention provides a flow chart of a method for resource treatment of tantalum-niobium acid wastewater. DETAILED DESCRIPTION

[0021] The present invention provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0022] The tantalum-niobium acid wastewater and the potassium salt aqueous solution are mixed to carry out a crystallization reaction, and after solid-liquid separation, a potassium fluorosilicate crystal product and a silicon removal liquid are obtained;

[0023] The potassium fluorosilicate crystal product is washed with water to obtain potassium fluorosilicate.

[0024] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0025] The present invention mixes tantalum niobium acid wastewater and potassium salt aqueous solution for crystallization reaction, and obtains potassium fluorosilicate crystal product and silicon removal liquid after solid-liquid separation. In the present invention, the tantalum niobium acid wastewater contains Si element and F element, and the mass concentration of the Si element is preferably 20-40 g / L, and specifically 32.51 g / L or 25 g / L in the embodiment. The mass concentration of the F element is preferably 110-160 g / L, and specifically 154.80 g / L or 130.21 g / L in the embodiment. The potassium salt aqueous solution is specifically a potassium chloride aqueous solution. The mass concentration of potassium salt in the potassium salt aqueous solution is preferably 200-300 g / L, and specifically 250 g / L. When the tantalum niobium acid wastewater and the potassium salt aqueous solution are mixed, the reaction excess coefficient of potassium salt in the potassium salt aqueous solution is preferably 1-2, and specifically 1, 1.1 or 1.2 in the embodiment. The reaction excess coefficient of the potassium salt is the ratio of the actual use mass to the theoretical use mass when potassium salt reacts with the tantalum niobium acid wastewater to generate potassium fluorosilicate.

[0026] In the present invention, the temperature of the crystallization reaction is room temperature (25°C) and the pressure is normal pressure (101Kpa). The mixing is preferably: adding the potassium salt aqueous solution to the tantalum-niobium acid wastewater; the mixing is carried out under stirring, and the stirring speed is preferably 50-200rpm, and specifically 75rpm in the embodiment. The conversion time is preferably 50-200min, and specifically 60min, 120min or 150min in the embodiment. After the potassium salt aqueous solution is added, a crystallization mixed slurry is obtained; the present invention preferably also includes: continuing the crystallization reaction under the condition of standing, and the standing time is preferably 30-180min, and specifically 30min, 60min or 180min in the embodiment. .

[0027] In a specific embodiment of the present invention, the specific implementation method of mixing the tantalum-niobium acid wastewater and the potassium salt aqueous solution for crystallization reaction preferably includes: adding the potassium salt aqueous solution into the tantalum-niobium acid wastewater for mixing, and obtaining a crystallization mixed slurry after the potassium salt aqueous solution is added; and continuing the crystallization reaction of the crystallization mixed slurry under static conditions.

[0028] After obtaining the potassium fluorosilicate crystalline product, the present invention washes the potassium fluorosilicate crystalline product with water to obtain potassium fluorosilicate. The water used for the water washing is specifically industrial water. The water washing is preferably multiple water washings, and the total volume of the water used for the water washing and the mass ratio of the potassium fluorosilicate crystalline product are preferably (300-500) L: 300 kg. The washing method of the water washing is preferably centrifugal washing. The water washing also obtains washing water (water after washing), and the pH value of the washing water is 4-5. After the water washing is completed, the present invention preferably centrifuges and spins the washed product to obtain the potassium fluorosilicate. In the present invention, the particle size range of the potassium fluorosilicate is -60 mesh to +200 mesh, that is, the material under the 60 mesh sieve and the material on the 200 mesh sieve. In the present invention, the purity of the potassium fluorosilicate is >99%, the chloride ion content is <0.1%, and the moisture content is <5%.

[0029] The present invention preferably further comprises using the wash water to prepare a potassium salt aqueous solution. In a specific embodiment of the present invention, the wash water and the potassium salt are mixed to obtain the potassium salt aqueous solution, and the potassium salt is preferably potassium chloride.

[0030] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0033] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0034] (2) taking 2 L of tantalum-niobium acid wastewater with a component content of Si: 32.51 g / L and F: 154.80 g / L, starting stirring, controlling the stirring speed at 75 rpm, adding the potassium chloride solution obtained in step (1) at a potassium chloride excess coefficient of 1.0 at 25° C. and a pressure of 101 KPa, controlling the conversion time to 60 min, and standing for 30 min after the conversion is completed to precipitate potassium fluorosilicate crystals;

[0035] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor (silicon content: 0.82 g / l, fluorine content: 9.3 g / l);

[0036] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L (total water volume) is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0037] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0038] In this embodiment, the fluorine recovery rate in the tantalum-niobium acidic wastewater is 80.5%, the potassium fluorosilicate content is 99.28%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0039] Example 2

[0040] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0041] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0042] (2) taking 2 L of tantalum-niobium acid wastewater with a component content of Si: 32.51 g / L and F: 154.80 g / L, starting stirring, controlling the stirring speed at 75 rpm, adding the potassium chloride solution obtained in step (1) at a potassium chloride excess coefficient of 1.2 at 25° C. and a pressure of 101 KPa, controlling the conversion time to 60 min, and standing for 30 min after the addition to precipitate potassium fluorosilicate crystals;

[0043] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor;

[0044] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L of water is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0045] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0046] In this embodiment, the fluorine recovery rate in the tantalum-niobium acidic wastewater is 83.8%, the potassium fluorosilicate content is 98.27%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0047] Example 3

[0048] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0049] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0050] (2) taking 2 L of tantalum-niobium acid wastewater with a component content of Si: 32.51 g / L and F: 154.80 g / L, starting stirring, controlling the stirring speed at 75 rpm, adding the potassium chloride solution obtained in step (1) at a potassium chloride excess coefficient of 1.1 at 25° C. and a pressure of 101 KPa, controlling the conversion time to 120 min, and standing for 60 min after the addition is completed to precipitate potassium fluorosilicate crystals;

[0051] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor;

[0052] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L of water is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0053] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0054] In this embodiment, the fluorine recovery rate in the tantalum-niobium acidic wastewater is 82.3%, the potassium fluorosilicate content is 98.88%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0055] Example 4

[0056] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0057] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0058] (2) 10,000 L of tantalum-niobium acid wastewater with a component content of Si: 25 g / L and F: 130.21 g / L was transferred into a potassium fluorosilicate synthesis tank, stirring was started, the stirring speed was controlled at 75 rpm, and the potassium chloride solution obtained in step (1) was added at a potassium chloride excess coefficient of 1.0 at 25° C. and a pressure of 101 KPa. The conversion time was controlled at 120 min. After the addition was completed, the solution was allowed to stand for 180 min to precipitate potassium fluorosilicate crystals;

[0059] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor;

[0060] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L of water is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0061] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0062] In this embodiment, the fluorine recovery rate in the tantalum-niobium acidic wastewater is 80.2%, the potassium fluorosilicate content is 99.1%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0063] Example 5

[0064] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0065] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0066] (2) 10,000 L of tantalum-niobium acid wastewater with a component content of Si: 25 g / L and F: 130.21 g / L was transferred into a potassium fluorosilicate synthesis tank, stirring was started, the stirring speed was controlled at 75 rpm, and the potassium chloride solution obtained in step (1) was added at a potassium chloride excess coefficient of 1.2 at 25° C. and a pressure of 101 KPa. The conversion time was controlled at 120 min. After the addition was completed, the solution was allowed to stand for 180 min to precipitate potassium fluorosilicate crystals;

[0067] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor;

[0068] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L of water is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0069] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0070] In this embodiment, the fluorine recovery rate in the tantalum-niobium acid wastewater is 83.4%, the potassium fluorosilicate content is 99.2%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0071] Example 6

[0072] This embodiment provides a method for resource treatment of tantalum-niobium acid wastewater, comprising the following steps:

[0073] (1) Prepare 250 g / L potassium chloride solution for standby use;

[0074] (2) 10,000 L of tantalum-niobium acid wastewater with a component content of Si: 25 g / L and F: 130.21 g / L was transferred into a potassium fluorosilicate synthesis tank, stirring was started, the stirring speed was controlled at 75 rpm, and the potassium chloride solution obtained in step (1) was added at a potassium chloride excess coefficient of 1.0 at 25° C. and a pressure of 101 KPa. The conversion time was controlled at 150 min. After the addition was completed, the solution was allowed to stand for 180 min to precipitate potassium fluorosilicate crystals;

[0075] (3) separating the crystals obtained in step (2) to obtain potassium fluorosilicate crystals and a mother liquor;

[0076] (4) The potassium fluorosilicate crystals obtained in step (3) are added to industrial water, 300 kg of the crystals are added to 300 L of water for washing, 300 L of water is evenly divided into 3 centrifugal washings, the pH of the washing water is controlled at 4 to 5 and then centrifuged to dry, and finally a potassium fluorosilicate product (particle size range -60 mesh to +200 mesh) and washing water are obtained.

[0077] (5) The washing water obtained in step (4) is used for preparing the potassium chloride solution in step (1).

[0078] In this embodiment, the fluorine recovery rate in the tantalum-niobium acidic wastewater is 82.5%, the potassium fluorosilicate content is 99.15%, the chloride ion content is <0.1%, the moisture content is <5%, and the particle size is -60 mesh to +200 mesh.

[0079] Comparative Example 1

[0080] The preparation method is the same as that of Example 1, except that the stirring speed is 200 rpm, and the particle size of the obtained potassium fluorosilicate is too small (particle size range is -300 mesh to +500 mesh), which does not meet the product requirements.

[0081] Comparative Example 2

[0082] The preparation method is basically the same as that in Example 4, except that: the potassium chloride solution is directly separated after being added without being allowed to stand for 180 minutes, and the recovery rate of fluorine in the tantalum-niobium acid wastewater is 75.8%.

[0083] Comparative Example 3

[0084] The preparation method is basically the same as that of Example 4, except that potassium chloride solution is added at an excess coefficient of 2.0, and the purity of the obtained potassium fluorosilicate product is 95.2%.

[0085] From the above examples, it can be seen that the method provided by the present invention first uses a potassium salt aqueous solution to treat tantalum niobium acid wastewater, and recovers the fluorine resources in the tantalum niobium acid wastewater in the form of potassium fluorosilicate, which can recover more than 80% of the fluorine resources in the tantalum niobium acid solution.

[0086] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for resource treatment of tantalum-niobium acid wastewater, characterized in that: The following steps are involved: The tantalum-niobium acid wastewater and the potassium salt aqueous solution are mixed to carry out a crystallization reaction, and after solid-liquid separation, a potassium fluorosilicate crystal product and a potassium fluorosilicate mother liquor are obtained; The potassium fluorosilicate crystal product is washed with water to obtain potassium fluorosilicate.

2. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1, characterized in that: The potassium salt aqueous solution is a potassium chloride aqueous solution.

3. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1 or 2, characterized in that: The mass concentration of potassium salt in the potassium salt aqueous solution is 200-300 g / L.

4. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1, characterized in that: When the tantalum-niobium acid wastewater and the potassium salt aqueous solution are mixed, the reaction excess coefficient of the potassium salt in the potassium salt aqueous solution is 1 to 1.

5.

5. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1, characterized in that: The tantalum-niobium acid wastewater contains Si and F elements, the mass concentration of the Si element is 25-35 g / L, and the mass concentration of the F element is 110-155 g / L.

6. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1, characterized in that: The temperature of the crystallization reaction is room temperature and the pressure is normal pressure.

7. The method for resource treatment of tantalum-niobium acid wastewater according to any one of claims 1 to 6, characterized in that: The mixing is as follows: adding the potassium salt aqueous solution into the tantalum-niobium acid wastewater; the mixing is carried out under stirring conditions, the stirring speed is 50-200 rpm, and the potassium salt aqueous solution is added for 20-40 minutes.

8. The method for resource treatment of tantalum-niobium acid wastewater according to claim 7, characterized in that: After the potassium salt aqueous solution is added, a crystallization mixed solution is obtained; and the method further comprises: continuing the crystallization reaction of the crystallization mixed solution under a standing condition, wherein the standing time is 0.5 to 3 hours.

9. The method for resource treatment of tantalum-niobium acid wastewater according to claim 1, characterized in that: The water washing also produces washing water, wherein the pH value of the washing water is 4 to 5; The method also includes: using the wash water to prepare a potassium salt aqueous solution.

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