Method for supernormal enrichment of waste acid rhenium based on primary arsenic sulfide colloid

Abstract

The invention belongs to the technical field of hydrometallurgy and resource recovery, and particularly relates to a waste acid rhenium supernormal enrichment method based on primary arsenic sulfide colloid. The method comprises the following steps: 1) recovering the metal smelting waste acid, filtering to remove suspended matters, sequentially adding an arsenic source and a sulfur source under an acidic condition, and stirring to generate primary arsenic sulfide colloid; 2) carrying out heating reaction on the primary arsenic sulfide colloid, and stirring until a turbid solution is formed; and (3) putting the filtered and separated rhenium-rich vulcanized filter residues and alkali liquor into a high-pressure reaction kettle together, preferentially dissolving out rhenium in the form of ReO4 <-> into a leaching solution through oxygen pressure leaching, and recovering the ReO4 <-> in the leaching solution through an extraction or ion exchange method to obtain an ammonium rhenate product. The method has very important significance on recovery and enrichment of rhenium in the metal waste acid, the rhenium recovery rate limit can reach almost 99.9%, the rhenium element with extremely high value can return to an industrial chain again, direct discharge pollution of the waste acid is reduced, economic benefits are improved, and meanwhile interference of arsenate ions in the waste acid is remarkably inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and resource recovery, and in particular relates to a method for super-enriching contaminated rhenium acid based on primary arsenic sulfide colloid. Background Art

[0002] Rhenium, a rare earth metal, is widely used in aerospace, electronics, catalysts, and other fields. However, my country's rhenium reserves are very limited, and the country relies primarily on imports. Rhenium is found in copper and molybdenum ores, and although its content is low, the scale of copper smelting is enormous. The amount of rhenium dispersed in waste acid is substantial, yet it remains largely unrecovered. Therefore, the efficient extraction of rhenium from waste acid is a worthy technical challenge.

[0003] Currently, the main processes for directly recovering rhenium from waste acid include: ion exchange, activated carbon adsorption, liquid membrane, solvent extraction, chemical precipitation, etc. Activated carbon adsorption and ion exchange are not suitable for waste acid with extremely low rhenium content, a wide variety of impurities, and high content. In addition, the amount of rhenium adsorbed is greatly affected by the temperature during the adsorption process, the acidity of the waste acid, the contact area, etc. Although the liquid membrane method is applicable to waste acid systems with low rhenium content, its research is more limited to the laboratory and has not been applied industrially. Solvent extraction is the most widely studied and applied method, with a wide range of extractants to choose from, but the reagent loss is large and the economic benefits are low. The chemical precipitation method has problems such as low rhenium recovery rate and easy to cause secondary pollution of SO2 and As.

[0004] In order to improve the recovery efficiency and economic value of rhenium, the present invention proposes an extraordinary enrichment method based on primary arsenic sulfide colloid, which has excellent rhenium enrichment effect, simple operation process and lower cost. The rhenium concentration in copper smelting waste acid is low (usually <100 mg / L), but the total amount is large. The traditional process has problems such as poor selectivity, high cost, and susceptibility to arsenic interference. Although the traditional sulfide precipitation method has a certain enrichment effect on rhenium, it is limited by the influence of the complex system of waste acid. The coexisting ions are easily precipitated into the sulfide slag due to sulfide, which reduces the enrichment degree of rhenium. This patent utilizes the high specific surface area and active sites of primary arsenic sulfide colloids, and achieves rhenate (ReO4 - ) of abnormal enrichment. Summary of the Invention

[0005] In order to solve the problems of low rhenium recovery efficiency, complicated process and large reagent loss in existing metal smelting waste acid, the present invention provides a method for extraordinary enrichment of rhenium in waste acid based on primary arsenic sulfide colloid.

[0006] The main objectives of the present invention are: 1. It can effectively recover rhenium from waste acid; 2. Ensure high recovery rate, which can reach more than 99%; 3. Ensure that the impurity content in the recycled material is low and the target material has a high purity.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions.

[0008] A method for the extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloids. The method comprises: 1) Recovering metal smelting waste acid and filtering to remove suspended solids, sequentially adding arsenic source and sulfur source under acidic conditions, and in situ generating primary arsenic sulfide colloid with highly active surface under mechanical stirring; 2) heating the primary arsenic sulfide colloid system and continuously stirring it to form a turbid liquid system through Ostwald ripening of the colloid particles, and obtaining a rhenium-containing arsenic sulfide composite filter residue through adsorption and solid-liquid separation; 3) placing the rhenium-containing sulfide composite filter residue in an autoclave, adding alkaline solution for oxygen pressure leaching, and converting rhenium into ReO4 - form into alkaline leachate; 4) Use the extractant to perform multi-stage countercurrent extraction on the leachate, and obtain high-purity ammonium rhenate solution through ammonia back extraction, or use anion exchange resin to selectively adsorb ReO4 - The rhenium is then recovered by desorption with aqueous ammonia.

[0009] As a preference, In step 1), the Re content in the metal smelting waste acid is 10 to 100 mg / L.

[0010] As a preference, Step 1) The acidic conditions are controlled to have a pH value of 0.5 to 2.0, and hydrochloric acid and / or sulfuric acid and / or nitric acid are used to regulate the pH value; Step 1) The arsenic source is a soluble arsenic salt, and the sulfur source is a soluble sulfur salt; the sulfur salt includes sodium sulfite and / or sodium sulfide and / or polysulfide; In step 1), the equivalent ratio of S to As in the arsenic source and the sulfur source is 1.4 to 1.8.

[0011] As a preference, In step 2), the temperature of the temperature-elevated reaction is controlled to be 50-100° C., and the reaction time is 1-5 h.

[0012] As a preference, Step 3) The alkali solution is sodium hydroxide or potassium hydroxide solution, and its pH value is 10-14.

[0013] As a preference, In step 3), the oxygen partial pressure during the pressure leaching is 0.3-0.8 MPa. The pressure leaching temperature is 100-180°C. The pressure leaching time is 1-7 hours. The oxidant used in the pressure leaching is a combination of one or more of industrial oxygen, air, ozone, and hydrogen peroxide.

[0014] Step 4) The rhenium recovery method is to selectively extract rhenium in the leachate with an extractant and then strip the rhenium from the organic phase with ammonia, or selectively adsorb the rhenium with an ion exchange resin and then desorb the rhenium with ammonia.

[0015] The core of the technical solution of the present invention is to achieve ultra-high ratio enrichment of target elements by means of specific adsorption between coexisting elements. Therefore, the present invention first performs a simple particulate matter removal treatment on the waste acid (the metal smelting waste acid in the present invention generally refers to copper smelting waste acid and molybdenum smelting waste acid, and copper smelting waste acid is the actual main research object) to reduce the interference of particulate matter. On this basis, after adjusting the pH value to a suitable value, arsenic source and sulfur source are added to form arsenic sulfide colloid. During the temperature reaction, arsenic sulfide colloid reacts with ReO4 - It shows strong specific adsorption. The surface of arsenic sulfide colloid forms negatively charged adsorption sites, which can preferentially react with ReO4 - It binds to arsenate ions (AsO3 3- ) has a strong inhibitory adsorption effect, making the Re / As separation coefficient in the actual waste acid reach more than 1000. This combination has the characteristics of specificity, high efficiency and stability, making ReO4 - After enrichment, it can be stably present, and further auxiliary stirring is performed to allow the arsenic sulfide colloid to fully contact ReO4 - The actual enrichment ratio can reach 100 to 150 times or even higher. - The continuous enrichment of ReO4 in the solution will - The arsenic sulfide colloid is continuously entangled and coated, and finally precipitated in the form of particles. Since the rhenium content in the waste acid is not high, the solution will turn into a suspension state after the precipitation is complete. At this time, it can be confirmed that ReO4 - The enrichment is completed and the enrichment end point is reached.

[0016] After the enrichment is completed, the filter residue containing rhenium is separated, dissolved in alkali solution, and then leached by oxygen pressure to obtain ReO4 - into the leachate in the form of water, and then the ReO4 - It is converted into ammonium rhenate product, ultimately achieving extraordinary enrichment, separation and recovery of rhenium in metal waste acid.

[0017] The beneficial effects of the present invention are: The present invention is of great significance for the recovery and enrichment of rhenium in metal waste acid. The maximum rhenium recovery rate can reach 99.9%. It can not only allow the trace rhenium element in the waste acid that is difficult to separate and recover but has extremely high value to return to the industrial chain, but also significantly suppress the interference of arsenate ions in the recovery process, solving the problems of traditional processes, greatly improving the enrichment of rhenium, and achieving higher economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The XRD characterization results of the recovered liquid of the experimental groups of Examples 1-6 under different usage ratios of filter residue and sodium hydroxide aqueous solution; Figure 2 The XRD characterization results of the filter residues of the experimental groups of Examples 1-6 are shown; Figure 3 These are the SEM characterization results of the filter residues under different stirring time conditions of the experimental groups of Examples 1-6. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to specific embodiments and the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0020] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0021] Unless otherwise specified, the Re content in the copper smelting waste acid used in the embodiments of the present invention is 50 mg / L.

[0022] Example 1 A method for super-enriching rhenium in polluted acid based on primary arsenic sulfide colloid, the method comprising: 1) Recovering the copper smelting waste acid and filtering it to remove solid impurities, adjusting the pH to 1.0 with industrial hydrochloric acid, and then sequentially adding sodium arsenate and sodium sulfide (or anhydrous sodium sulfite). After the addition of sodium arsenate, the initial arsenic concentration in the mixed solution was controlled to be 0.15 g / L and the atomic molar equivalent ratio S / As was 1.2 to 1.5. The solution was stirred for 15 minutes to generate primary arsenic sulfide colloid. 2) The primary arsenic sulfide colloid was heated to 90°C for 1 hour and stirred until a turbid solution formed. The precipitate was centrifuged at 5000 rpm for 6 minutes, filtered, and washed with deionized water. 3) The filter residue was leached with a 1 mol / L sodium hydroxide aqueous solution at a ratio of 10 g:1 L. The oxidant for the pressure leaching was hydrogen peroxide. The recovered leachate was heated to 150°C and maintained at an oxygen partial pressure of 0.5 MPa for 2 h to leach rhenium metal. The rhenium was then recovered from the leachate by extraction or ion exchange.

[0023] In this example, experiments were conducted with different S / As ratios and sulfur sources. The initial Re content was calculated using raw copper smelting waste acid. The Re content in the filtrate after separation of the filter residue in step 3) was characterized and the residual Re content was calculated. The precipitation efficiency was calculated as ((initial Re content - residual Re content) / initial Re content) × 100%. The results are shown in the following table.

[0024] From the table above, we can see that anhydrous sodium sulfite as a sulfur source has a higher precipitation efficiency for rhenium. When other conditions remain unchanged, the best rhenium precipitation efficiency is achieved when the S / As molar ratio is 1.4, reaching 99.85%, close to 99.9%. Based on the above, additional experiments were conducted using anhydrous sodium sulfite as the sulfur source, with S / As molar ratios of 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0. Based on the experimental results, to ensure a precipitation efficiency of over 98%, the S / As molar ratio needs to be controlled between 1.4 and 1.8. To achieve an extremely high yield of over 99% precipitation efficiency, the S / As molar ratio needs to be relatively strictly controlled between 1.4 and 1.6.

[0025] Secondly, taking the experimental group of Example 1-6 as an example, the amount ratio of the filter residue and the sodium hydroxide aqueous solution was controlled to be 5-15 g:1 L, and the recovered liquid was subjected to XRD characterization, and the filter residue of the original experimental group of Example 1-6 was subjected to XRD characterization. The characterization results were as follows: Figure 1 and Figure 2 As can be seen from the figure, the recovered liquid and filter residue after enrichment in the technical solution of the present invention have extremely high purity and show good selectivity.

[0026] In addition, based on the experimental groups of Examples 1-6, the primary arsenic sulfide colloid was generated by stirring for 1 min, 5 min and 15 min in step 1), and the filter residue in step 3) was recovered and characterized by SEM. The characterization results are as follows: Figure 3 As shown in Figure 2, it can be seen that as the stirring time increases, the specific capture effect of the formed primary arsenic sulfide colloid on rhenium increases. Therefore, the optimal stirring time should be controlled within 10 to 20 minutes.

[0027] Example 2 Based on the experimental groups in Examples 1-6 above, this example treated waste acid from copper smelting with different sources. The initial arsenic concentration in the mixed liquor after sodium arsenate addition was controlled at 0-0.4 g / L, and the same experimental preparation and characterization were performed. The specific results are shown in the table below. The initial arsenic concentration represents the relative dosage of sodium arsenate; the initial liquid phase concentration represents the concentrations of As and Re in the liquid phase sampled before stirring; the residual liquid concentration represents the concentrations of As and Re in the filtrate after separation of the filter residue in step 3). The precipitation efficiency was calculated as in Example 1, and the As precipitation efficiency was calculated as for Re; and the solid phase composition represents the composition of the filter residue.

[0028] The results in the table above show that at an arsenic concentration of 0 g / L, the rhenium precipitation efficiency was 13.95%, indicating that in the absence of arsenic, rhenium precipitation efficiency is low. At an arsenic concentration of 0.025 g / L, the precipitation efficiency increased significantly, reaching 76.8%. This result indicates that the presence of arsenic helps improve rhenium precipitation efficiency, but it remains at a low plateau. When the arsenic concentration exceeds 0.15 g / L, rhenium is almost completely precipitated, and as the arsenic concentration increases, the precipitation efficiency continues to increase, reaching 99.97%. This indicates that within a certain concentration range, increasing arsenic concentration significantly improves rhenium precipitation efficiency. However, at arsenic concentrations of 0.3 g / L and 0.4 g / L, the precipitation efficiency remains unchanged and even slightly decreases to 99.96%. Finally, at an arsenic concentration of 0.4 g / L, the precipitation efficiency remains at 99.96%, similar to that at 0.3 g / L. This indicates that the precipitation efficiency in this concentration range has reached saturation and is no longer significantly affected by arsenic concentration.

[0029] Furthermore, the solid phase composition in the table above shows that at an arsenic concentration of 0.025 g / L, the solid phase percentage of rhenium reaches a maximum of 8.45%. When the arsenic concentration increases to 0.05 g / L, the solid phase percentage of arsenic significantly increases to 11.47%, while the solid phase percentage of rhenium decreases to 8.02% and the solid phase percentage of sulfur decreases to 80.51%. This indicates that the precipitation efficiency of rhenium gradually increases with increasing arsenic concentration. As the arsenic concentration continues to increase to 0.1 g / L, 0.15 g / L, and 0.2 g / L, although the solid phase percentage of rhenium gradually decreases, the change is not significant, ranging from 7.19% to 7.95%. At this time, the solid phase percentage of arsenic gradually increases, remaining between 12.24% and 16.70%, while the solid phase percentage of sulfur gradually decreases, remaining between 76.11% and 79.81%. This indicates that the precipitation efficiency of rhenium gradually increases with increasing arsenic concentration. When the arsenic concentration continued to increase to 0.3 g / L and 0.4 g / L, the solid phase component proportion of rhenium significantly decreased to 4.36% and 3.88%, the solid phase proportion of arsenic increased to 19.79% and 20.35%, and the solid phase proportion of sulfur decreased to 75.85% and 75.77%. This shows that the precipitation efficiency of rhenium has been close to saturation. Continuing to increase the arsenic concentration will significantly reduce the solid phase component proportion of rhenium. At this time, the reaction is almost no longer affected by the arsenic concentration.

[0030] It can be clearly seen from the above examples that the present invention can effectively achieve extraordinary enrichment and recovery of rhenium in a waste acid system, with a recovery rate of over 99%, which is of great significance for the recovery of rare strategic metal rhenium.

Claims

1. A method for the extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid, characterized in that: The method comprises: 1) Recovering metal smelting waste acid and filtering to remove suspended solids, sequentially adding arsenic source and sulfur source under acidic conditions, and in situ generating primary arsenic sulfide colloid with highly active surface under mechanical stirring; 2) heating the primary arsenic sulfide colloid system and continuously stirring it to form a turbid liquid system through Ostwald ripening of the colloid particles, and obtaining a rhenium-containing arsenic sulfide composite filter residue through solid-liquid separation; 3) placing the rhenium-containing sulfide composite filter residue in an autoclave, adding alkaline solution for oxygen pressure leaching, and converting rhenium into ReO4 - form into alkaline leachate; 4) Use the extractant to perform multi-stage countercurrent extraction on the leachate, and obtain high-purity ammonium rhenate solution through ammonia back extraction, or use anion exchange resin to selectively adsorb ReO4 - The rhenium is then recovered by desorption with aqueous ammonia.

2. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: In step 1), the Re content in the metal smelting waste acid is 10 to 100 mg / L.

3. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: Step 1) The acidic conditions are controlled to have a pH value of 0.5 to 2.0, and hydrochloric acid and / or sulfuric acid and / or nitric acid are used to regulate the pH value; Step 1) The arsenic source is a soluble arsenic salt, and the sulfur source is a soluble sulfur salt; the sulfur salt includes sodium sulfite and / or sodium sulfide and / or polysulfide; In step 1), the equivalent ratio of S to As in the arsenic source and the sulfur source is 1.4 to 1.

8.

4. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: In step 2), the temperature of the temperature-elevated reaction is controlled to be 50-100° C., and the reaction time is 1-5 h.

5. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: Step 3) The alkali solution is sodium hydroxide or potassium hydroxide solution, and its pH value is 10-14.

6. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: Step 3) The oxygen pressure leaching method comprises placing the rhenium-containing sulfide composite filter residue in a high-pressure reaction system, using at least one of industrial oxygen, air, ozone, and hydrogen peroxide as an oxidant under an oxygen partial pressure of 0.3-0.8 MPa and a temperature of 100-180°C, and regulating the leaching time to 1-7 hours to efficiently leach the rhenium in a soluble state.

7. The method for extraordinary enrichment of rhenium in polluted acid based on primary arsenic sulfide colloid according to claim 1, characterized in that: Step 4) The rhenium recovery method is to selectively extract rhenium in the leachate with an extractant and then strip the rhenium from the organic phase with ammonia, or selectively adsorb the rhenium with an ion exchange resin and then desorb the rhenium with ammonia.

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