Method for removing molybdenum from ammonium rhenate by flocculating and precipitating with ferric sulfate
Patent Information
- Application Number
- CN202610795214.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-04
- Publication Date
- 2026-08-28
AI Technical Summary
针对现有技术的不足，本发明提供了一种硫酸铁絮凝沉淀的铼酸铵除钼方法，解决了铼酸铵除钼效果不佳，铼回收率低的问题
本发明中，通过“弱碱反应-弱酸回调”的pH分段精准调控，沉淀前pH控制在8~10，确保铁离子缓慢水解并与钼结合，避免生成大量胶体；沉淀后回调至5~7，利用氢氧化铁的“捕捉效应”深度除钼，同时利用pH变化解吸被夹带的铼，显著提高了铼的收率；且通过控制硫酸铁用量0.2~0.8g/L，既保证了钼的充分沉淀，又避免了过量铁剂带来的过滤困难和铼的吸附损失；实现将钼含量降至1ppm以下的同时，规避传统铁盐法中铼夹带损失严重的问题。
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of rare metal hydrometallurgy and high-purity material preparation, and particularly relates to a method for removing molybdenum from ammonium rhenate flocculation and precipitation of iron sulfate. BACKGROUND
[0002] In recent years, rhenium (Re) is a kind of strategic rare metal, which is widely used in aerospace single crystal high-temperature alloy and petroleum chemical catalyst. In the process of copper smelting, rhenium is often oxidized and volatilized as a by-product element into the dust, and finally enriched in the waste acid after the acid-making process, and recovered in the form of ammonium rhenate (NH4ReO4).
[0003] Because rhenium and molybdenum belong to the same group in the periodic table, their chemical properties are very similar, and both exist in the form of oxygen-containing anions in aqueous solution, which leads to great difficulty in separation. The existing molybdenum removal technologies mainly include solvent extraction method, ion exchange method and sulfide precipitation method. The solvent extraction method needs to use a large amount of organic solvent, which has high cost and environmental pressure; the ion exchange method is prone to saturation of the resin when treating high-concentration feed solution, and the desorption is complicated; the traditional sulfide precipitation method (such as adding ammonium sulfide) can precipitate molybdenum, but produces toxic hydrogen sulfide gas, and the precipitation and filtration are difficult. The iron salt precipitation method is one of the research hotspots in recent years. Trivalent iron ions (Fe3+) can form iron-molybdenum polyacid complexes or adsorptive precipitates with molybdate under certain pH conditions, but they are extremely sensitive to pH value. If the pH value is not properly controlled, the iron ions are difficult to completely hydrolyze and precipitate, and the molybdenum removal is not complete; if the pH value is too high, a large amount of iron hydroxide colloid is generated in ammonium rhenate, which is easy to adsorb and co-precipitate, causing serious loss of rhenium. Therefore, how to ensure high recovery rate of rhenium while achieving deep removal of molybdenum is a technical problem to be solved in the field. SUMMARY
[0004] (I) Technical problems solved In view of the deficiencies of the prior art, the present application provides a method for removing molybdenum from ammonium rhenate flocculation and precipitation of iron sulfate, which solves the problems of poor molybdenum removal effect and low rhenium recovery rate of ammonium rhenate.
[0005] (II) Technical solutions In order to achieve the above object, the present application is realized by the following technical solutions: A method for removing molybdenum from ammonium rhenate flocculation and precipitation of iron sulfate, the method comprising: S1. Dissolving crude ammonium rhenate solid containing molybdenum impurities into deionized water to obtain an ammonium rhenate solution; slowly adding an acid-base reagent under stirring to adjust the pH value of the solution to 8-10 to obtain a pretreated solution; S2. Adding iron sulfate solid or iron sulfate solution to the pretreated solution, the amount of iron sulfate added being 0.2-0.8 g / L; after the addition is completed, stirring and reacting sufficiently at 60-85℃; S3. After the reaction is completed, continue stirring, and adjust the pH value of the solution to 5-7; then perform solid-liquid separation to obtain ammonium rhenate purification liquid after molybdenum removal and molybdenum-containing iron slag; S4. The ammonium rhenate purification liquid is cooled and crystallized, the crystals are separated by vacuum filtration, and the white high-purity ammonium rhenate crystals are dried.
[0006] Preferably, in S1, the molybdenum content in the crude ammonium rhenate solid containing molybdenum impurities is 0.001%-0.002%, and the rhenium content is 99.9%-99.99%.
[0007] Preferably, in S1, the concentration of the ammonium rhenate solution is 100g / L-303g / L.
[0008] Preferably, in S2, the stirring reaction time after the feeding is completed is 20-40 minutes.
[0009] Preferably, the acid-base reagent used to adjust the pH value of the solution includes ammonia, sodium hydroxide solution, sulfuric acid, and hydrochloric acid.
[0010] (Three) beneficial effects The application provides a method for removing molybdenum from ammonium rhenate flocculated and precipitated by iron sulfate. Compared with the prior art, the method has the following beneficial effects: In the application, through pH segment precise control of "weak alkali reaction-weak acid readjustment", the pH before precipitation is controlled at 8-10, the slow hydrolysis of iron ions is ensured, and the combination with molybdenum is avoided to prevent the generation of a large amount of colloid; the pH is readjusted to 5-7 after precipitation, the "capture effect" of iron hydroxide is used to deeply remove molybdenum, the desorption of rhenium entrained by the pH change is used, and the yield of rhenium is significantly improved; and by controlling the amount of iron sulfate to be 0.2-0.8g / L, the sufficient precipitation of molybdenum is ensured, and the problems of filtration difficulty and rhenium adsorption loss caused by excessive iron agent are avoided; the molybdenum content is reduced to below 1ppm, and the problem of serious rhenium entrainment loss in the traditional iron salt method is avoided. BRIEF DESCRIPTION OF DRAWINGS
[0011] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0012] Figure 1 The flow chart of the method in the embodiments of the application. DETAILED DESCRIPTION
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0014] This application provides a method for removing molybdenum from ammonium perrylate through ferric sulfate flocculation precipitation, which solves the problems of poor molybdenum removal effect and low rhenium recovery rate of ammonium perrylate.
[0015] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods. Example
[0016] like Figure 1 As shown, this invention provides a method for removing molybdenum from ammonium rhenium by ferric sulfate flocculation precipitation, the method comprising: S1. Crude ammonium perrylate dissolution and pH pre-adjustment 85 kg of crude ammonium perrylate containing molybdenum impurities was weighed and dissolved in 280 L of deionized water to obtain a solution with an ammonium perrylate concentration of 303 g / L. With the stirrer on, acid and base reagents were slowly added to adjust the pH of the solution to 8.5 to obtain a pretreated solution. At this point, the solution was clear and transparent with no obvious precipitate. S2. Ferric sulfate precipitation reaction Ferric sulfate solid was added to the pretreatment solution at a concentration of 0.6 g / L. After the addition was complete, the mixture was stirred at 80°C for 20 minutes. During the reaction, the solution gradually became turbid and a yellowish-brown precipitate was formed. S3. Post-reaction pH adjustment and solid-liquid separation After the reaction was completed, the mixture was stirred for 30 minutes and the pH of the solution was adjusted to 6.5. Then, solid-liquid separation was performed to obtain the molybdenum-removed ammonium rhenium purified solution and molybdenum-containing iron slag. S4. Post-processing The purified ammonium perryate solution was cooled and crystallized, the crystals were separated by vacuum filtration, and dried at 105℃ for 5 hours to obtain white high-purity ammonium perryate crystals.
[0017] The product was tested and found to contain 0.13 ppm of Mo and 0.12 ppm of Fe.
[0018] The compositional analysis results of the crude ammonium rhenium solid containing molybdenum impurities in S1 showed that the rhenium content was 99.99% and the molybdenum content was 0.002%. Example
[0019] This invention provides a method for removing molybdenum from ammonium rhenium by ferric sulfate flocculation precipitation, the method comprising: S1. Crude ammonium perrylate dissolution and pH pre-adjustment 85 kg of crude ammonium perrylate containing molybdenum impurities was weighed and dissolved in 290 L of deionized water to obtain a solution with an ammonium perrylate concentration of 293 g / L. With the stirrer on, acid and base reagents were slowly added to adjust the pH of the solution to 8 to obtain a pretreated solution. At this point, the solution was clear and transparent with no obvious precipitate. S2. Ferric sulfate precipitation reaction Ferric sulfate solid was added to the pretreatment solution at a concentration of 0.8 g / L. After the addition was complete, the mixture was stirred at 85°C for 30 minutes. During the reaction, the solution gradually became turbid and a yellowish-brown precipitate was formed. S3. Post-reaction pH adjustment and solid-liquid separation After the reaction was completed, the mixture was stirred for 30 minutes and the pH of the solution was adjusted to 5. Then, solid-liquid separation was performed to obtain the molybdenum-removed ammonium rhenium purified solution and molybdenum-containing iron slag. S4. Post-processing The purified ammonium perryate solution was cooled and crystallized, the crystals were separated by vacuum filtration, and dried at 102℃ for 6 hours to obtain white high-purity ammonium perryate crystals.
[0020] The product was tested and found to contain less than 0.05 ppm of Mo and 0.48 ppm of Fe.
[0021] The compositional analysis results of the crude ammonium rhenium solid containing molybdenum impurities in S1 showed that the rhenium content was 99.99% and the molybdenum content was 0.0015%. Example
[0022] This invention provides a method for removing molybdenum from ammonium rhenium by ferric sulfate flocculation precipitation, the method comprising: S1. Crude ammonium perrylate dissolution and pH pre-adjustment Weigh 30 kg of crude ammonium permanganate containing molybdenum impurities and dissolve it in 300 L of deionized water to obtain a solution with an ammonium permanganate concentration of 100 g / L. With the stirrer on, slowly add acid and base reagents to adjust the pH of the solution to 10 to obtain a pretreated solution. At this point, the solution is clear and transparent with no obvious precipitate. S2. Ferric sulfate precipitation reaction Ferric sulfate solution was added to the pretreatment solution at a concentration of 0.2 g / L. After the addition was complete, the mixture was stirred at 60°C for 40 minutes. During the reaction, the solution gradually became turbid and a yellowish-brown precipitate was formed. S3. Post-reaction pH adjustment and solid-liquid separation After the reaction was completed, the mixture was stirred for 30 minutes and the pH of the solution was adjusted to 7. Then, solid-liquid separation was performed to obtain the molybdenum-removed ammonium rhenium purified solution and molybdenum-containing iron slag. S4. Post-processing The purified ammonium perrylate solution was cooled and crystallized, the crystals were separated by vacuum filtration, and dried at 110℃ for 5 hours to obtain white high-purity ammonium perrylate crystals.
[0023] The product was tested and found to contain less than 0.05 ppm of Mo and 0.47 ppm of Fe.
[0024] The compositional analysis results of the crude ammonium rhenium solid containing molybdenum impurities in S1 showed that the rhenium content was 99.9% and the molybdenum content was 0.001%.
[0025] Comparative example: The difference from Example 1 is that the pH of the crude ammonium perrylate solution was directly adjusted to 10, and then 0.6 g / L ferric sulfate was added to carry out the reaction.
[0026] The addition of iron salts instantly generates a large amount of reddish-brown colloid, making filtration extremely difficult. Significant rhenium loss occurs. This indicates that at excessively high pH, iron rapidly forms ferric hydroxide colloid, leading to the adsorption and co-precipitation of large amounts of rhenium. After post-treatment, the product contains numerous impurities, with Mo content at 17 ppm and Fe content at 30 ppm.
[0027] In summary, compared with the prior art, the present invention has the following beneficial effects: 1. In this embodiment of the invention, the pH is precisely controlled in stages through "weak base reaction - weak acid correction". Before precipitation, the pH is controlled at 8-10 to ensure that iron ions are slowly hydrolyzed and combined with molybdenum, avoiding the generation of a large amount of colloid. After precipitation, the pH is corrected to 5-7. The "capture effect" of ferric hydroxide is used to deeply remove molybdenum. At the same time, the pH change is used to desorb the rhenium that was entrained, which significantly improves the rhenium yield. This achieves the goal of reducing the molybdenum content to below 1 ppm while avoiding the problem of severe rhenium entrainment loss in the traditional iron salt method.
[0028] 2. In this embodiment of the invention, by controlling the amount of ferric sulfate to 0.2~0.8 g / L, both the sufficient precipitation of molybdenum and the filtration difficulties and rhenium adsorption losses caused by excessive iron agent are ensured.
[0029] 3. In the embodiments of the present invention, the reagent ferric sulfate is widely available and inexpensive, and does not produce toxic gases such as H2S. The entire process is carried out at room temperature and pressure, with low equipment requirements and is easy to promote industrially.
[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for removing molybdenum from ammonium perrylate by ferric sulfate flocculation precipitation, characterized in that, The method includes: S1. Dissolve crude ammonium perrye solid containing molybdenum impurities in deionized water to obtain an ammonium perrye solution; slowly add acid or base reagents while stirring to adjust the pH of the solution to 8-10 to obtain a pretreated solution; S2. Add solid ferric sulfate or ferric sulfate solution to the pretreatment solution, with the amount of ferric sulfate added being 0.2~0.8 g / L; after the addition is complete, stir the mixture at 60~85℃ until the reaction is complete. S3. After the reaction is complete, continue stirring and adjust the pH of the solution to 5-7; then perform solid-liquid separation to obtain the molybdenum-removed ammonium rhenium purified solution and molybdenum-containing iron slag. S4. Cool the purified ammonium perrylate solution to crystallize it, separate the crystals by vacuum filtration, and dry it to obtain white high-purity ammonium perrylate crystals.
2. The method for removing molybdenum from ammonium rhenium by ferric sulfate flocculation precipitation as described in claim 1, characterized in that, In S1, the crude ammonium rhenium solid containing molybdenum impurities has a molybdenum content of 0.001% to 0.002% and a rhenium content of 99.9% to 99.99%.
3. The method for removing molybdenum from ammonium perrylate by ferric sulfate flocculation precipitation as described in claim 1, characterized in that, In S1, the concentration of the ammonium perrylate solution is 100 g / L to 303 g / L.
4. The method for removing molybdenum from ammonium perrylate by ferric sulfate flocculation and precipitation as described in claim 1, characterized in that, In step S2, the stirring reaction time after the addition of materials is completed is 20-40 minutes.
5. The method for removing molybdenum from ammonium perrylate by ferric sulfate flocculation precipitation as described in claim 1, characterized in that, Acid-base reagents used to adjust the pH of a solution include: ammonia, sodium hydroxide solution, sulfuric acid, and hydrochloric acid.