Method for intensively decomposing tungsten ore by using sulfuric acid

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a method for intensively decomposing tungsten ore by sulfuric acid, which adopts a low-cost single sulfuric acid system for treatment instead of high-valence alkali and volatile acid, thereby saving the treatment cost and reducing the equipment corrosion. The usage amount of sodium hydroxide outside the system is reduced, so that the generation of high-salinity wastewater is reduced, and the wastewater treatment cost is also saved; compared with conventional acid decomposition, the tungsten conversion rate is greater than 99% and the tungsten leaching rate after ammonia dissolution is greater than 98% after an auxiliary decomposition aid and sulfuric acid reinforced decomposition are adopted; and compared with alkali autoclaving, a large amount of energy is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for strengthening the decomposition of tungsten ore by sulfuric acid. Background Art

[0002] The classic method for processing tungsten ore in industry at present is high temperature and high pressure sodium hydroxide pressure cooking to obtain crude sodium tungstate and alkali cooking residue, and the crude sodium tungstate solution is transformed into ammonium tungstate solution by ion exchange or solvent extraction. However, this method has the following problems: first, the alkali used is expensive, resulting in high alkali decomposition cost; second, a large amount of alkali cooking residue is produced, which is solid hazardous waste and needs to be outsourced to qualified enterprises for treatment, which greatly increases the treatment cost; third, a large amount of sodium hydroxide is added, and sodium salt is added outside the system, which produces a large amount of high-salt wastewater, and the cost of wastewater treatment is high.

[0003] In order to reduce the decomposition cost of tungsten ore and achieve the reduction of slag, the acid treatment technology is a more reasonable process. Researchers have carried out technical research on the acid treatment of tungsten ore very early. The prior art records a method of using sulfuric acid to decompose black and white tungsten mixed ore, adding black tungsten ore to a certain concentration of sulfuric acid solution for transformation reaction, obtaining transformation filtrate and transformation material, adding a certain concentration of ammonium salt or sodium salt solution to the transformation material, obtaining ammonium tungstate solution or sodium tungstate solution, and achieving most of the decomposition of black and white tungsten ore; the prior art records a method of acid decomposition of black and white tungsten mixed ore to prepare tungsten products, through leaching-filtration washing-hydrogen peroxide extraction-decomposition and extraction of tungsten, thereby obtaining relatively pure tungstic acid, the decomposition slag produced by this process is gypsum, which is not a hazardous waste, but the process uses a large amount of hydrogen peroxide and has a high production cost. The prior art records a method for extracting tungsten by decomposing wolframite or black wolframite under pressure with sulfur-phosphorus mixed acid. A mixed acid of phosphoric acid and sulfuric acid is used as a reaction medium, and the reaction system is pressurized to make the reaction temperature 110-250°C. The extraction process does not require the addition of calcium-containing compounds to transform the wolframite, which simplifies the production process. However, this technology uses high-pressure processing technology, which places higher requirements on reaction equipment and operation.

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing ammonium tungstate solution by acid decomposing tungsten ore. The preparation method is simple, has a short process flow, uses less reagents, and reduces the generation of high-salt wastewater. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a method for decomposing tungsten ore by strengthening sulfuric acid.

[0006] According to one aspect of the present invention, the present invention provides the following technical solution:

[0007] A method for decomposing tungsten ore by strengthening sulfuric acid comprises the following steps:

[0008] S1, grinding the tungsten ore and mixing it with sulfuric acid, and then roasting it at low temperature;

[0009] S2, mixing the roasted material with water, stirring and leaching, and filtering to obtain a filter residue;

[0010] S3, washing the filter residue with water and then dissolving it with ammonia to obtain an ammonium tungstate solution.

[0011] The invention adopts single sulfuric acid and strengthens the decomposition of tungsten ore through low temperature roasting, thereby enhancing the decomposition efficiency of tungsten ore.

[0012] As a preferred embodiment of the method for decomposing tungsten ore with enhanced sulfuric acid according to the present invention, in step S1, a decomposition aid is added before low-temperature roasting; the decomposition aid is one of CeO2 and Ce(SO4)2 or a mixture of the two in any proportion, and the mass used is 0.1 to 5% of the mass of the tungsten ore.

[0013] The present invention adds a cerium-based decomposition aid to react with tungsten ore to generate a complex cerium-tungsten compound, collectively known as cerium tungstate (Ce2W3O 12 ), cerium tungstate decomposes into cerium sulfate and tungstic acid in high temperature and concentrated sulfuric acid, thereby further realizing the efficient conversion of tungsten ore. The decomposition aid not only forms new compounds with tungsten, but also oxidizes Fe(II) to Fe(III), destroying the crystal phase structure of tungsten ore, further improving the decomposition rate of tungsten ore, and realizing the enhanced decomposition of tungsten ore only under normal pressure and single sulfuric acid system, with tungsten conversion rate greater than 99% and tungsten leaching rate greater than 98%. Moreover, the added cerium-based decomposition aid does not produce gas, is not flammable or explosive, and completely enters the solution after water immersion, without affecting the quality of subsequent products.

[0014] The reactions involved are as follows:

[0015] FeWO4+Ce(IV)→Ce2W3O 12 +Fe(III)

[0016] Ce2W3O 12 +H2SO4→Ce(III)+H2WO4+SO3

[0017] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore with sulfuric acid according to the present invention, wherein: in step S1, the content of tungsten trioxide in the tungsten ore is 1-80wt%, and the particle size of the tungsten ore is 10-400 mesh. More preferably, the content of tungsten trioxide in the tungsten ore is 40-70wt%, and the particle size of the tungsten ore is 100-300 mesh.

[0018] As a preferred embodiment of the method for decomposing tungsten ore with enhanced sulfuric acid according to the present invention, in step S1, the decomposition aid is CeO2, and the mass used is 0.5-1% of the mass of the tungsten ore.

[0019] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore with sulfuric acid according to the present invention, in step S1, the mass concentration of sulfuric acid is 80-96%, and the weight ratio of sulfuric acid to tungsten ore is 20-200%. More preferably, the mass concentration of sulfuric acid is 90-96%, and the weight ratio of sulfuric acid to tungsten ore is 100-150%.

[0020] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore with sulfuric acid described in the present invention, in step S1, the roasting temperature is 150-280°C, and the roasting time is 30-300 minutes. More preferably, the roasting temperature is 200-250°C, and the roasting time is 60-120 minutes.

[0021] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore with sulfuric acid described in the present invention, wherein: in step S2, the mass of water used is 1 to 10 times the mass of the tungsten ore, the leaching temperature is room temperature to 100°C, and the leaching time is 30 to 300 minutes. More preferably, the mass of water used is 3 to 6 times the mass of the tungsten ore, the leaching temperature is 50 to 80°C, and the leaching time is 60 to 120 minutes.

[0022] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore with sulfuric acid described in the present invention, in step S3, the water washing is performed by countercurrent washing until the acid content in the filter residue is less than 0.1 mol / L.

[0023] As a preferred embodiment of the method for decomposing tungsten ore with enhanced sulfuric acid according to the present invention, in step S3, the washing liquid after washing is returned to step S2 to be mixed with water and leached.

[0024] As a preferred embodiment of the method for strengthening the decomposition of tungsten ore by sulfuric acid according to the present invention, in step S3, when performing ammonia dissolution, the ratio of the amount of ammonia used to the amount of tungsten trioxide in the filter residue is (2-20):1, the ammonia dissolution time is 30-300 minutes, the temperature is room temperature to 70°C, and the solid-liquid ratio is 1:(1-10). More preferably, the ratio of the amount of ammonia used to the amount of tungsten trioxide in the filter residue is (2-5):1, the ammonia dissolution time is 30-60 minutes, the temperature is 50-70°C, and the solid-liquid ratio is 1:(2-6).

[0025] The beneficial effects of the present invention are as follows:

[0026] (1) The present invention adopts a low-cost single sulfuric acid system for treatment, replacing high-valent alkali and volatile acid, saving treatment costs and reducing equipment corrosion;

[0027] (2) The amount of sodium hydroxide used outside the system is reduced, thereby reducing the generation of high-salt wastewater, thereby saving wastewater treatment costs;

[0028] (3) After using auxiliary decomposition aids and sulfuric acid to enhance decomposition, compared with conventional acid decomposition, the tungsten conversion rate is greater than 99%, and the tungsten leaching rate after ammonia dissolution is greater than 98%; compared with alkaline pressure cooking, a lot of energy is saved. DETAILED DESCRIPTION

[0029] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a method for decomposing tungsten ore with enhanced sulfuric acid, which uses a single sulfuric acid to decompose tungsten ore through low-temperature roasting, thereby enhancing the decomposition efficiency of tungsten ore. The present invention adds a cerium-based decomposition aid to react with tungsten ore to generate a complex cerium-tungsten compound, collectively referred to as cerium tungstate (Ce2W3O 12 ), cerium tungstate decomposes into cerium sulfate and tungstic acid in high temperature and concentrated sulfuric acid, thereby further realizing the efficient conversion of tungsten ore. The decomposition aid not only forms new compounds with tungsten, but also oxidizes Fe(II) to Fe(III), destroying the crystal phase structure of tungsten ore, further improving the decomposition rate of tungsten ore, and realizing the enhanced decomposition of tungsten ore only under normal pressure and single sulfuric acid system, with tungsten conversion rate greater than 99% and tungsten leaching rate greater than 98%. Moreover, the added cerium-based decomposition aid does not produce gas, is not flammable or explosive, and completely enters the solution after water immersion, without affecting the quality of subsequent products.

[0031] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0032] Example 1

[0033] The specific operation process in this embodiment is as follows:

[0034] Take 1000g wolframite (WO3% = 65wt%) and grind it to obtain 300-mesh wolframite, add 10g CeO2 solid, add 1000g industrial sulfuric acid (concentration of 96wt%) after mixing, stir evenly and put it into a muffle furnace for roasting for 2h (temperature is 200℃), take it out while hot, rinse it with 4000mL water and transfer it to a reactor, heat it to 80℃ and stir it for 2h, filter it, and obtain 3460mL of leaching solution and 920g of wet leaching residue; add 4000mL of water to the leaching residue for washing, the washing temperature is room temperature, the washing time is 30min, and 3970mL of primary washing solution is obtained after filtering. With 890g of primary washing slag, the obtained primary washing can be used for the leaching water of the next batch of roasted ore; add 4000mL of water to the primary washing slag for secondary washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3950mL of secondary washing liquid and 880g of secondary washing slag are obtained, and the obtained secondary washing liquid can be used for the next batch of primary washing water; add 4000mL of water to the secondary washing slag for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3960mL of tertiary washing liquid and 850g of tertiary washing slag are obtained, and the obtained tertiary washing liquid can be used for the next batch of secondary washing water. Add 3000mL of 6mol / L ammonia water to the tertiary washing slag, stir at room temperature for 60min, and dissolve in ammonia. After filtering, 2890mL of ammonium tungstate solution (the tungsten content in the ammonium tungstate solution is 220g / L) and 265g of ammonia slag (the tungsten content in the ammonia slag is 4.05wt%) are obtained.

[0035] According to calculation in this embodiment, the leaching rate of tungsten is 98.34%.

[0036] Calculation method of leaching rate,

[0037] Where: V 钨酸铵溶液 Indicates the volume of ammonium tungstate solution in mL; C 钨 Indicates the content of tungsten in ammonium tungstate solution, in g / L; m 氨溶渣 Indicates the content of tungsten in ammonia slag, in wt%; g 氨溶渣 Indicates the weight of ammonia slag in g.

[0038] Example 2

[0039] The difference from Example 1 is that CeO2 is not added.

[0040] It was determined that the volume of the ammonium tungstate solution was 2908 mL, the tungsten content was 211 g / L, the ammonia slag weighed 272 g, the tungsten content was 12.83 wt %, and the tungsten leaching rate was 94.62%, which was 3.72% less than that in Example 1, indicating that the addition of the decomposition aid of the present invention can further improve the conversion of tungsten in tungsten ore, thereby improving the leaching efficiency of tungsten.

[0041] Example 3

[0042] The specific operation process in this embodiment is as follows:

[0043] Take 1000g of scheelite (WO3% = 56wt%) and grind it into 300 mesh, add 100g of Ce(SO4)2 solid, mix it, then add 2000g of industrial sulfuric acid (concentration of 80wt%), stir it evenly, put it into a muffle furnace and roast it for 30h (temperature is 280℃), take it out while hot, rinse it with 10000mL of water and transfer it to a reactor, stir it at room temperature for 2 hours, filter it, and obtain 9424ml of leaching liquid and 872g of wet leaching residue; add 1000mL of water to the leaching residue for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 979ml of primary washing liquid and 842g of primary washing residue are obtained. The obtained primary washing It can be used for the leaching water of the next batch of roasted ore; add 1000mL of water to the first washing slag for secondary washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 956mL of secondary washing liquid and 930g of secondary washing slag are obtained, and the obtained secondary washing liquid can be used for the next batch of primary washing water; add 1000mL of water to the secondary washing slag for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 966mL of tertiary washing liquid and 936g of tertiary washing slag are obtained, and the obtained tertiary washing liquid can be used for the next batch of secondary washing water. Add 4000mL of a mixed solution (4mol / L ammonia water and 2mol / L ammonium carbonate) to the tertiary washing slag, stir at room temperature for 60min, dissolve in ammonia, and after filtering, 3290mL of ammonium tungstate solution (the tungsten content in the ammonium tungstate solution is 165g / L) and 480g of ammonia slag (the tungsten content in the ammonia slag is 1.25wt%) are obtained. It is calculated that the tungsten leaching rate is 98.91%.

[0044] Example 4

[0045] The specific operation process in this embodiment is as follows:

[0046] Take 1000g of black and white tungsten ore (WO3% = 55wt%) and grind it into 300 mesh, add 50g of CeO2 solid, mix it, and then add 1500g of industrial sulfuric acid (concentration of 96wt%), stir it evenly, put it into a muffle furnace and roast it for 2h (temperature is 250℃), take it out while hot, rinse it with 4000mL of water, transfer it to a reactor, heat it to 80℃ and stir it for 2h, filter it, and get 3556mL of leaching solution and 896g of wet leaching residue; add 4000mL of water to the leaching residue for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, get 3830mL of primary washing solution and 86 5g of primary washing slag, the primary washing can be used for the leaching water of the next batch of roasted ore; add 4000mL of water to the primary washing slag for secondary washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3915mL of secondary washing liquid and 855g of secondary washing slag are obtained, and the secondary washing liquid can be used for the next batch of primary washing water; add 4000mL of water to the secondary washing slag for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3943mL of tertiary washing liquid and 848g of tertiary washing slag are obtained, and the tertiary washing liquid can be used for the next batch of secondary washing water. Add 5000mL of a mixed solution (2mol / L ammonia water and 2mol / L ammonium carbonate) to the tertiary washing slag, stir at room temperature for 300min, and dissolve in ammonia. After filtering, 4710mL of ammonium tungstate solution (the tungsten content in the ammonium tungstate solution is 115g / L) and 424g of ammonia slag (the tungsten content in the ammonia slag is 1.11wt%) are obtained. It is calculated that the leaching rate of tungsten is 99.14%.

[0047] Comparative Example 1

[0048] 1000g industrial sulfuric acid (concentration of 96wt%) was dissolved in 4L water, and then mixed with 1000g wolframite (WO3%=65wt%) ground to 300 mesh, heated to 80℃ and stirred for 2h, filtered to obtain 3570mL leaching solution and 941g wet leaching residue; 4000mL water was added to the obtained leaching residue for washing, the washing temperature was room temperature, the washing time was 30min, and after filtering, 3956mL primary washing solution and 921g primary washing residue were obtained, and the obtained primary washing can be used for the next batch of roasted ore. leaching water; add 4000mL water to the first washing residue for secondary washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3942mL of secondary washing liquid and 898g of secondary washing residue are obtained, and the obtained secondary washing liquid can be used for the next batch of primary washing water; add 4000mL water to the secondary washing residue for washing, the washing temperature is room temperature, the washing time is 30min, and after filtering, 3968mL of tertiary washing liquid and 889g of tertiary washing residue are obtained, and the obtained tertiary washing liquid can be used for the next batch of secondary washing water. Add 3000mL of 6mol / L ammonia water to the tertiary washing residue, stir at room temperature for 60min, and dissolve in ammonia. After filtering, 2864mL of ammonium tungstate solution (the content of tungsten in the ammonium tungstate solution is 164g / L) and 732g of ammonia slag (the content of tungsten in the ammonia slag is 22.92wt%) are obtained. It is calculated that the tungsten leaching rate is 73.68%.

[0049] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for decomposing tungsten ore by sulfuric acid enhancement, characterized in that: The steps include: S1, grinding the tungsten ore and mixing it with sulfuric acid, and then roasting it at low temperature; S2, mixing the roasted material with water, stirring and leaching, and filtering to obtain a filter residue; S3, washing the filter residue with water and then dissolving it with ammonia to obtain an ammonium tungstate solution.

2. The method for decomposing tungsten ore by sulfuric acid enhancement according to claim 1, characterized in that: In the step S1, before low-temperature roasting, a decomposition aid is added; the decomposition aid is one of CeO2 and Ce(SO4)2 or a mixture of the two in any proportion, and the mass used is 0.1-5% of the mass of the tungsten ore.

3. The method for decomposing tungsten ore with enhanced sulfuric acid according to claim 1, characterized in that: In the step S1, the content of tungsten trioxide in the tungsten ore is 1-80wt%, and the particle size of the tungsten ore is 10-400 meshes.

4. The method for decomposing tungsten ore with sulfuric acid according to claim 2, characterized in that: In the step S1, the decomposition aid is CeO2, and the mass used is 0.5-1% of the mass of the tungsten ore.

5. The method for decomposing tungsten ore by sulfuric acid enhancement according to claim 1, characterized in that: In the step S1, the mass concentration of sulfuric acid is 80-96%, and the weight ratio of sulfuric acid to tungsten ore is 20-200%.

6. The method for decomposing tungsten ore with sulfuric acid according to claim 1, characterized in that: In the step S1, the calcination temperature is 150-280° C., and the calcination time is 30-300 min.

7. The method for decomposing tungsten ore with sulfuric acid according to claim 1, characterized in that: In step S2, the mass of water used is 1 to 10 times the mass of the tungsten ore, the leaching temperature is room temperature to 100° C., and the leaching time is 30 to 300 minutes.

8. The method for decomposing tungsten ore with sulfuric acid according to claim 1, characterized in that: In step S3, the water washing is performed by countercurrent washing until the acid content in the filter residue is less than 0.1 mol / L.

9. The method for decomposing tungsten ore with enhanced sulfuric acid according to claim 1, characterized in that: In step S3, the washing liquid after washing is returned to step S2 to be mixed with water and leached.

10. The method for decomposing tungsten ore with enhanced sulfuric acid according to claim 1, characterized in that: In the step S3, when ammonia dissolution is performed, the ratio of ammonia dosage to tungsten trioxide in the filter residue is (2-20):1, the ammonia dissolution time is 30-300 min, the temperature is room temperature to 70° C., and the solid-liquid ratio is 1:(1-10).

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