Method for recycling waste materials in potassium fluotantalate production process

Abstract

The invention provides a method for recycling waste materials in a potassium fluotantalate production process, which comprises the following steps: by taking potassium fluotantalate crystallization mother liquor and crystallization waste materials as raw materials, heating, adjusting acid, dissolving, neutralizing and precipitating, carrying out solid-liquid separation and the like, converting the potassium fluotantalate crystallization waste materials into tantalum hydroxide solids, and returning the tantalum hydroxide solids to a production source to be reused as tantalum raw materials. According to the method, tantalum resources in the potassium fluotantalate crystallization mother liquor can be effectively recycled, meanwhile, high-impurity potassium fluotantalate crystal waste generated in the production process is converted into tantalum hydroxide solids, the recovery rate of the tantalum resources is increased, and waste of the tantalum resources is reduced. Compared with the prior art, the process flow is simple, the operation is convenient, the recovery flow can be effectively shortened, the problems of impurity enrichment and equipment blockage are avoided, the normal operation of equipment and the high purity and stability of the potassium fluotantalate product are ensured, and the industrial application prospect is good.

Description

Technical Field

[0001] The invention relates to the technical field of tantalum resource recovery, in particular to a method for recycling waste in the production process of potassium fluorotantalate, and belongs to the technical field of metal material metallurgy and chemical waste treatment. Background Art

[0002] Tantalum is a high-value rare metal, widely used in high-tech fields such as tantalum capacitors, high-temperature alloys, target materials, chemical corrosion protection, national defense and military industry, and cemented carbide. As a key element in high-tech industries, the effective utilization and recycling of tantalum resources are particularly important. However, the reserves of tantalum on the earth are relatively small. At present, the world's proven tantalum resources are mainly distributed in Australia and Brazil. Therefore, all countries have listed it as a strategic mineral resource. In order to maximize the use of tantalum resources, the tantalum and niobium industry has conducted a lot of research on the recovery and reuse of tantalum resources.

[0003] In the existing potassium fluorotantalate production process, the recovery technology of potassium fluorotantalate crystallization mother liquor mainly focuses on recovering tantalum resources through extraction or recycling. However, during the filtration and drying process of potassium fluorotantalate crystallization, contaminated crystal waste will be generated. The impurity content in this part of waste is high, which is difficult to effectively remove and recover through traditional methods such as recrystallization, resulting in its ineffective utilization and waste of resources.

[0004] In the prior art, there are studies on the recovery of tantalum resources from potassium fluorotantalate crystallization mother liquor. For example, the patent "Method for Recovering Tantalum Resources from Potassium Fluorotantalate Crystallization Mother Liquor" (Application Number: CN202010615924.8) applied by Jiangxi Tuohong New Materials Co., Ltd. proposes a method for recovering tantalum resources from potassium fluorotantalate crystallization mother liquor. The method includes four steps: acidification, extraction, separation and recovery: first, the potassium fluorotantalate crystallization mother liquor is acidified, and then an extractant is added for extraction and separation to obtain a tantalum-containing extract and a raffinate; then, the tantalum-containing extract is separated and purified to obtain a tantalum-containing separated liquid and a separated crystallization mother liquor, and finally the crystallization mother liquor is recycled. However, this method is mainly aimed at the recovery of tantalum resources in the potassium fluorotantalate crystallization mother liquor, and no effective treatment method is proposed for the waste generated during the crystallization process, and it is difficult to solve the problem of high impurities and difficulty in removing impurities in the crystal waste.

[0005] In addition, the patent "A Method for Preparing Potassium Fluotantalate" (application number: CN201410278306.3) applied by Zhuzhou Cemented Carbide Group Co., Ltd. proposes a technology for preparing potassium fluorotantalate through the method of internal circulation of mother liquor. In the production process of potassium fluorotantalate, this method does not use liquid ammonia neutralization process to recover and treat the mother liquor after crystallization, but adopts the method of internal circulation of mother liquor to prepare potassium fluorotantalate. This method uses potassium fluorotantalate crystallization mother liquor instead of water, decomposes it with hydrofluoric acid and sulfuric acid, and then adds fluorosilicic acid and sulfuric acid for low-acid preparation and low-acid extraction to finally obtain potassium fluorotantalate. However, this technology also does not propose an effective recovery plan for the crystal waste generated during the crystallization process, resulting in the problem that impurities in the waste cannot be removed and the waste utilization rate is low.

[0006] Therefore, in the prior art, there is no perfect method for treating and effectively recycling the contaminated crystal waste in the production process of potassium fluorotantalate. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a new process for converting potassium fluorotantalate waste into tantalum hydroxide and returning it to production as a tantalum raw material. The present invention can effectively remove impurities in crystal waste and realize the recycling and reuse of tantalum resources, thereby improving resource utilization and reducing the waste of tantalum resources.

[0008] A method for recycling waste materials in the production process of potassium fluorotantalate, the method uses potassium fluorotantalate crystallization mother liquor and crystallization waste materials as raw materials, and comprises the following steps:

[0009] Step 1: Heat the potassium fluorotantalate crystallization mother liquor to 80-85°C and keep stirring;

[0010] Step 2: Add industrial hydrofluoric acid to the heated potassium fluorotantalate crystal mother liquor and stir evenly;

[0011] Step 3: adding potassium fluorotantalate crystal waste to the solution treated in step 2, and maintaining the solution temperature between 80-85° C. for 1-2 hours until the waste is completely dissolved and the solution changes from turbid to transparent;

[0012] Step 4: Add ammonia gas to the transparent solution of step 3 for neutralization reaction. When the pH value of the solution reaches 8-9, stop adding ammonia and continue to stir evenly.

[0013] Step 5: When the temperature of the solution in step 4 drops to about 30° C., the solution is subjected to solid-liquid separation to obtain tantalum hydroxide solid;

[0014] Step 6: Wash the obtained tantalum hydroxide solid to remove ammonia nitrogen, then remove moisture by squeezing to obtain a tantalum hydroxide filter cake, which is returned to the production process as a tantalum raw material.

[0015] The potassium fluorotantalate crystallization mother liquor and crystallization waste are crystal wastes generated in the filtering and drying processes during the production of potassium fluorotantalate.

[0016] The industrial hydrofluoric acid is industrial hydrofluoric acid with a concentration of 55% by mass.

[0017] The steam pressure when the potassium fluorotantalate crystallization mother liquor is heated in step 1 is 0.1-0.3Mpa.

[0018] When the potassium fluorotantalate crystallization mother liquor is heated in step 1, the rotation speed of the stirring paddle is controlled at 70-80 rpm.

[0019] In step 3, when potassium fluorotantalate crystal waste is added to the heated solution, the addition ratio of the waste is 10-20% of the total mass of the potassium fluorotantalate crystal mother liquor.

[0020] The ammonia introduced during the neutralization reaction in step 4 is gaseous ammonia.

[0021] In step 5, the solid-liquid separation is carried out using a plate and frame filter press.

[0022] The tantalum content in the filtrate after washing in step 6 is less than 0.02 g / L.

[0023] The washed tantalum hydroxide filter cake in step 6 is squeezed to remove moisture and then directly returned to the tantalum raw material production process without affecting the quality of the final potassium fluorotantalate product.

[0024] The method for recycling waste materials in the production process of potassium fluorotantalate proposed by the present invention has the following beneficial effects:

[0025] Improve resource utilization:

[0026] This method can effectively recycle the tantalum resources in the potassium fluorotantalate crystal mother liquor, and at the same time convert the high-impurity potassium fluorotantalate crystal waste generated in the production process into tantalum hydroxide solid, greatly improving the resource recovery rate of potassium fluorotantalate.

[0027] The process is simple and easy to operate:

[0028] The invention does not require long-term acidification treatment, has a fast reaction process, is easy to operate, can effectively shorten the recovery process, and improves production efficiency.

[0029] Avoid equipment clogging and accumulation of harmful impurities:

[0030] The present invention effectively avoids the enrichment of impurities in the mother liquor and the precipitation of crystals through the steps of heating, acid adjustment, dissolution, neutralization precipitation, solid-liquid separation and the like, prevents the problem of mother liquor crystals blocking equipment during the hydrometallurgical process, and ensures the normal operation of the equipment.

[0031] Improve product quality:

[0032] The recovery method of the present invention can convert potassium fluorotantalate crystal waste with high impurities into tantalum hydroxide solid, which can then be reused in the production process as a tantalum raw material without affecting the quality of the potassium fluorotantalate product, thereby ensuring the stability and high purity of the product.

[0033] Significant environmental benefits:

[0034] The process flow of the present invention effectively solves the problem of recycling waste materials in the production process of potassium fluorotantalate, avoids direct discharge of waste materials and its pollution to the environment, and realizes green production and sustainable utilization of resources.

[0035] In summary, the present invention has significant advantages in improving resource utilization, simplifying process operation, avoiding impurity enrichment and improving product quality, and can be widely used in the field of potassium fluorotantalate and tantalum resource recovery. DETAILED DESCRIPTION

[0036] Preferred embodiments of the present invention are given below to illustrate the technical solutions of the present invention in detail.

[0037] Example 1

[0038] 1. Add raw materials:

[0039] Add 1000 L of potassium fluorotantalate crystallization mother liquor into the reactor, turn on the stirring paddle, and control the stirring paddle speed at 70-80 rpm.

[0040] 2. Heating:

[0041] The potassium fluorotantalate crystallization mother liquor is heated by steam to raise the solution temperature to 80°C, and the steam pressure is controlled at 0.1-0.3Mpa.

[0042] 3. Acidification treatment:

[0043] 50 L of 55% by mass industrial hydrofluoric acid was added to the heated solution and stirred for 5 minutes.

[0044] 4. Add waste and keep warm:

[0045] Reduce the amount of steam introduced, maintain the solution temperature at 80-85°C, slowly add 190 kg of potassium fluorotantalate crystal waste, and keep warm for 2 hours. Observe the state of the solution until the potassium fluorotantalate crystals are completely dissolved and the solution changes from turbid to transparent.

[0046] 5. Neutralization precipitation:

[0047] Ammonia gas was introduced into the above transparent solution to carry out precipitation reaction. When the pH value of the solution reached 8, the introduction of ammonia was stopped and stirring was continued to be uniform.

[0048] 6. Solid-liquid separation:

[0049] When the solution temperature drops to about 30° C., stirring is stopped and the solution is pressed into a plate and frame filter press for solid-liquid separation to obtain tantalum hydroxide solid.

[0050] 7. Washing and dehydration:

[0051] The tantalum hydroxide solid is washed to remove ammonia nitrogen, and the tantalum content in the filtrate is less than 0.02 g / L. The washed tantalum hydroxide solid is then squeezed and dehydrated to obtain a tantalum hydroxide filter cake.

[0052] Effect analysis:

[0053] Tantalum resource recovery rate: In this embodiment, the tantalum in the potassium fluorotantalate crystal waste is converted into tantalum hydroxide and then returned to the production source for reuse. The tantalum recovery rate can reach more than 98%, effectively improving the utilization efficiency of tantalum resources.

[0054] Impurity removal effect: The contents of C, Si and Ca in the tantalum hydroxide recovered and prepared by the method of the present invention are less than 0.1wt%, and the contents of As, Al, Pb, Fe, etc. are all less than 0.02wt%, indicating that the method can effectively purify tantalum resources without introducing additional impurities.

[0055] Improved production efficiency: The acidification treatment time in this embodiment is only 2 hours, which is much shorter than the 30 hours of acidification treatment time in the traditional method, and the process is more efficient.

[0056] Equipment operation stability: In this embodiment, by reasonably controlling the addition amount and dissolution temperature of potassium fluorotantalate waste, no equipment blockage and crystal precipitation problems were observed, the equipment operated smoothly, and the equipment maintenance cost was reduced.

[0057] Example 2

[0058] 1. Add raw materials:

[0059] Add 2000L of potassium fluorotantalate crystallization mother liquor into the reactor, turn on the stirring paddle, and control the stirring paddle speed at 70-80 rpm.

[0060] 2. Heating:

[0061] The potassium fluorotantalate crystallization mother liquor is heated by steam to raise the solution temperature to 80°C, and the steam pressure is controlled at 0.1-0.3Mpa.

[0062] 3. Acidification treatment:

[0063] 110 L of 55% by mass industrial hydrofluoric acid was added to the heated solution, and the mixture was stirred for 5 minutes.

[0064] 4. Add waste and keep warm:

[0065] Reduce the amount of steam introduced, maintain the solution temperature at 80-85°C, slowly add 380 kg of potassium fluorotantalate crystal waste, and keep warm for 2 hours. Observe the state of the solution until the potassium fluorotantalate crystals are completely dissolved and the solution changes from turbid to transparent.

[0066] 5. Neutralization precipitation:

[0067] Ammonia gas was introduced into the above transparent solution to carry out precipitation reaction. When the pH value of the solution reached 8, the introduction of ammonia was stopped and stirring was continued to be uniform.

[0068] 6. Solid-liquid separation:

[0069] When the solution temperature drops to about 30° C., stirring is stopped and the solution is pressed into a plate and frame filter press for solid-liquid separation to obtain tantalum hydroxide solid.

[0070] 7. Washing and dehydration:

[0071] The tantalum hydroxide solid is washed to remove ammonia nitrogen, and the tantalum content in the filtrate is less than 0.02 g / L. The washed tantalum hydroxide solid is then squeezed and dehydrated to obtain a tantalum hydroxide filter cake.

[0072] Effect analysis:

[0073] Tantalum resource recovery rate: In this embodiment, by increasing the processing volume of potassium fluorotantalate crystallization mother liquor and crystal waste, a larger scale of tantalum resource recovery is achieved. The final tantalum recovery rate can reach more than 97%, and the stable production of potassium fluorotantalate is maintained.

[0074] Optimization of reaction conditions: By appropriately adjusting the dosage of industrial hydrofluoric acid and the addition ratio of potassium fluorotantalate crystal waste, the dissolution efficiency of the crystal waste is further improved, the content of insoluble impurities in the reaction process is reduced, and the high efficiency of the entire process is ensured.

[0075] Improved product quality: The tantalum content in the filtrate of this embodiment is lower than 0.02 g / L, and the impurity level of the product is lower than the treatment result in the prior art, which has a higher market application value.

[0076] Process stability: By reasonably controlling the reaction temperature, stirring speed and neutralization precipitation conditions, in this embodiment, under large-scale production conditions, no equipment blockage and solution crystallization occurred, the process was stable and controllable, and the equipment maintenance cost was low.

[0077] Both Example 1 and Example 2 of the present invention can achieve efficient recycling of potassium fluorotantalate crystal waste under different processing scales, and have the advantages of high tantalum recovery rate, low impurity content, simple process flow, stable equipment operation, etc., which provide an effective solution for the recycling of waste materials in the production process of potassium fluorotantalate, and can be promoted and applied in large-scale industrial production.

Claims

1. A method for recycling waste materials in the production process of potassium fluorotantalate, characterized in that: The method uses potassium fluorotantalate crystallization mother liquor and crystallization waste as raw materials, and comprises the following steps: Step 1: Heat the potassium fluorotantalate crystallization mother liquor to 80-85°C and keep stirring; Step 2: Add industrial hydrofluoric acid to the heated potassium fluorotantalate crystal mother liquor and stir evenly; Step 3: adding potassium fluorotantalate crystal waste to the solution treated in step 2, and maintaining the solution temperature between 80-85° C. for 1-2 hours until the waste is completely dissolved and the solution changes from turbid to transparent; Step 4: Add ammonia gas to the transparent solution of step 3 for neutralization reaction. When the pH value of the solution reaches 8-9, stop adding ammonia and continue to stir evenly. Step 5: When the temperature of the solution in step 4 drops to about 30° C., the solution is subjected to solid-liquid separation to obtain tantalum hydroxide solid; Step 6: Wash the obtained tantalum hydroxide solid to remove ammonia nitrogen, then remove moisture by squeezing to obtain a tantalum hydroxide filter cake, which is returned to the production process as a tantalum raw material.

2. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1, characterized in that: The potassium fluorotantalate crystallization mother liquor and crystallization waste are crystal wastes generated in the filtering and drying processes during the production of potassium fluorotantalate.

3. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1 or 2, characterized in that: The industrial hydrofluoric acid is industrial hydrofluoric acid with a concentration of 55% by mass.

4. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1 or 3, characterized in that: The steam pressure when the potassium fluorotantalate crystallization mother liquor is heated in step 1 is 0.1-0.3Mpa.

5. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1, characterized in that: When the potassium fluorotantalate crystallization mother liquor is heated in step 1, the rotation speed of the stirring paddle is controlled at 70-80 rpm.

6. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1, characterized in that: In step 3, when potassium fluorotantalate crystal waste is added to the heated solution, the addition ratio of the waste is 10-20% of the total mass of the potassium fluorotantalate crystal mother liquor.

7. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1 or 6, characterized in that: The ammonia introduced during the neutralization reaction in step 4 is gaseous ammonia.

8. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1 or 7, characterized in that: In step 5, the solid-liquid separation is carried out using a plate and frame filter press.

9. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1, characterized in that: The tantalum content in the filtrate after washing in step 6 is less than 0.02 g / L.

10. The method for recycling waste materials in the production process of potassium fluorotantalate according to claim 1, characterized in that: The washed tantalum hydroxide filter cake in step 6 is squeezed to remove moisture and then directly returned to the tantalum raw material production process.