A method for purifying and recovering molybdenum metal from a uranium molybdenum ore leaching solution

Abstract

This invention belongs to the field of hydrometallurgical technology and relates to a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution. The method includes: adding an acidic flocculant to the filtrate after oxygen-pressure acid leaching, stirring and thickening, filtering, overflowing the concentrated supernatant into a potential regulating tank, adding hydrogen peroxide to the potential regulating tank for potential adjustment, and allowing it to stand for aging to obtain a settled filtrate and precipitate; filtering and cooling the settled filtrate to obtain a purified filtrate; collecting the settled precipitate, adding water to the precipitate for stirring and mixing, adding sodium carbonate to adjust the pH value, raising the temperature, continuing stirring, washing and filtering to obtain a filter cake and an alkaline leaching filtrate; recovering molybdenum metal from the filtered filter cake and alkaline leaching filtrate; adding acid to the alkaline leaching filtrate or purified filtrate to adjust the pH value, and extracting with an extractant to recover molybdenum metal. This invention can effectively reduce the turbidity of the acidic filtrate after oxygen-pressure acid leaching and improve the molybdenum recovery efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution. Background Technology

[0002] Uranium-molybdenum symbiotic deposits, as complex polymetallic minerals in China, have become a national strategic mineral resource for development and utilization. Through the innovation of hydrometallurgical technology and the application of new processes in recent years, the recovery and utilization rate of uranium-molybdenum symbiotic mineral resources has been greatly improved.

[0003] Currently, oxygen pressure acid leaching is a commonly used process for leaching and recovering metals from uranium-molybdenum symbiotic ores. The specific process route is as follows: ore crushing → water grinding → acid addition to slurry → oxygen pressure leaching of slurry → filtration and separation of slurry → clarification of filtrate by settling → fine filtration of filtrate → oxidation of filtrate to adjust potential → cooling of filtrate → extraction (separation and enrichment of uranium-molybdenum metals) → back-extraction of uranium-molybdenum → preparation of uranium-molybdenum products.

[0004] However, this process has the problem of low filtrate quality in metal recovery, which has a great impact on the operation of downstream fine filtration and extraction processes. The main problems are: (1) The turbidity of the filtrate after solid-liquid separation is between 200ppm and 500ppm. During the settling and clarification process, the finer mineral sands cannot sink due to gravity under the action of buoyancy, so the filtrate after settling and clarification still contains a lot of finer mineral sands and has high turbidity, reaching 150ppm-300ppm. This puts a lot of pressure on the downstream fine filtration. During the production process, the filter aid is frequently replaced and the solidified impurities are cleaned. The processing capacity and solid content control quality are affected, and the consumption of secondary filter aid is also too large. (2) During the clarification process of the filtrate, a large number of chemical impurities (Ca, Si, Fe, As, etc.) were not precipitated and intercepted before extraction. The impurity-containing filtrate entered the extraction process, and the impurities mixed with molybdenum, tertiary amine extractants, and acidic organophosphorus co-extractants during the extraction process. This resulted in frequent phase separation and unclear separation of the organic phase, emulsification of the organic phase, and the formation of a large number of molybdenum heteropolyacid salts and various macromolecular chelates, ultimately forming a large amount of three-phase precipitates. This also resulted in high extractant consumption during the extraction process, rapid generation of three-phase substances in the extraction equipment, difficulty in cleaning, and increased operating costs.

[0005] Therefore, there is an urgent need to develop a new process to solve the problems of high solid content and the need to purify chemical impurities in the filtrate after oxygen pressure acid leaching. Summary of the Invention

[0006] The purpose of this invention is to provide a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solutions. This method improves the operational quality and efficiency of the filtrate entering the fine filtration and extraction stages, while reducing the consumption of chemical raw materials such as filter aids and organic phases (extractants) required for these two processes. Simultaneously, it enables the efficient recovery of molybdenum metal from impurity precipitates generated during the aging stage of filtrate purification, further improving the utilization efficiency of molybdenum resources. It also effectively reduces the solid content and chemical element impurities in the acidic filtrate after oxygen pressure acid leaching, offering high efficiency, low cost, and environmental friendliness.

[0007] Technical solution to achieve the purpose of this invention:

[0008] A method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution, the method comprising:

[0009] Step 1: The uranium-molybdenum ore slurry is subjected to oxygen pressure leaching, flash evaporation to reduce temperature and pressure, and back-end cooling to obtain the leached ore slurry;

[0010] Step 2: Add acidic flocculant to the slurry after soaking in Step 1, mix quickly, and then filter to obtain the filtered slurry filtrate.

[0011] Step 3: Add acidic flocculant to the slurry filtrate after filtration in Step 2, stir and thicken, transport the bottom flocculent ore sand to the leaching slurry in Step 2, mix and filter, and overflow the thickened supernatant into the potential regulating tank to obtain overflow filtrate.

[0012] Step 4: Add hydrogen peroxide to the potential adjustment tank in step 3 to adjust the potential. Control the potential of the filtrate with a potentiometer to obtain the filtrate after potential adjustment.

[0013] Step 5: Pump the filtrate after potential adjustment in Step 4 into the clarification facility and let it stand for aging to obtain the filtrate and precipitate after standing for aging.

[0014] Step 6: Filter the filtrate after step 5 (after standing and aging) through a fine filtration device to obtain finely filtered filtrate.

[0015] Step 7: Cool the filtrate after fine filtration in Step 6 through a cooling device to obtain purified filtrate, which can be used in downstream extraction processes.

[0016] Step 8: Collect the precipitate after settling and aging in Step 5, add water to the precipitate and stir to mix, add sodium carbonate to adjust the pH value, heat up, continue stirring and then wash and filter to obtain filter cake and alkali leaching filtrate, and recover molybdenum metal from the filter cake and alkali leaching filtrate.

[0017] Step 9: Add acid to the filtrate after alkaline leaching in Step 8 to adjust the pH value, and then extract with an extractant; or mix the purified filtrate from Step 7 with the filtrate after alkaline leaching in Step 8, add acid to adjust the pH value, and then extract with an extractant to recover molybdenum metal after extraction.

[0018] The conditions for oxygen pressure leaching in step 1 are: temperature 162±1℃, pressure ≤0.95Mpa, oxygen partial pressure ≤40%, and oxygen pressure leaching time 1-1.5h; the conditions for flash evaporation cooling and depressurization are: temperature reduced to below 70℃, pressure reduced to 0.02-0.08Mpa; and the conditions for post-cooling are: addition of 20-30% carbide slag slurry, resulting in a post-leaching slurry acidity of 20-40g / l and a temperature below 80℃.

[0019] The acidic flocculant in steps 2 and 3 is a mixture of flocculants such as FZ3802, 25xv, 25s, 25v or higher, and the ratio of flocculant to water is 1:1000 by weight.

[0020] The amount of flocculant added in step 2 is 50-100 mg / L. 3 Add 1-3m of leaching pulp 3 The flocculant produced a turbidity of 200ppm-500ppm in the filtered slurry.

[0021] The amount of flocculant added in step 3 is 50-80 mg / L. 3 Add 0.2-0.5 mg of the filtered mineral slurry filtrate. 3 The flocculant is used, and the thickening process involves stirring the equipment at a speed of 3-5 min / r. The turbidity of the overflow filtrate is 80-100 ppm.

[0022] In step 4, the potential adjustment process involves controlling the filtrate potential from -450mV to -480mV using a potentiometer.

[0023] The settling and aging time in step 5 is 24 hours.

[0024] In step 6, the fine filtration device is a vacuum drum filter, and the filter aid for fine filtration is diatomaceous earth or a mixture of diatomaceous earth and perlite. The turbidity of the filtrate after fine filtration is reduced to 20-50 ppm.

[0025] The cooling temperature in step 7 is 25-32℃.

[0026] In step 8, the volume ratio of precipitate to water is 1:1, sodium carbonate is added to adjust the pH to 9.5-10, the temperature is raised to 60℃, and the stirring time is 30 minutes.

[0027] In step 9, acid is added to adjust the pH value to 2-3.

[0028] In step 9, the extractant is an organic phase extractant formed by mixing tertiary amine extractant, acidic organophosphorus synergistic extractant, and sulfonated kerosene in a volume ratio of 6.5%, 15%, and 78.5%.

[0029] The beneficial technical effects of this invention are as follows:

[0030] 1. The present invention provides a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution. By adding an acidic flocculant to the acidic filtrate after oxygen pressure acid leaching and thickening, the solid content of the filtrate is greatly reduced, and the turbidity of the filtrate is reduced from 200ppm-500ppm before thickening to below 100ppm. This reduces the pressure of downstream fine filtration and avoids the sedimentation of high-turbidity filtrate in the clarification container, thus reducing the impact on the clarification space of the filtrate.

[0031] 2. This invention provides a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution. After concentration, hydrogen peroxide is added to the upper, low-turbidity acidic filtrate to oxidize and adjust the filtrate potential. The filtrate is then allowed to stand for 24 hours for aging. During this aging process, due to the action of hydrogen peroxide, a large number of metal ions in the filtrate undergo redox reactions. Anions and cations combine with molybdate ions to form molybdenum heteropolyacid salts, and macromolecules formed by the coupling of fine mineral sands continuously precipitate out, forming precipitates. Most of these precipitates sink to the bottom of the clarification container under gravity, while a small portion floats in the filtrate and is intercepted during fine filtration. This significantly reduces impurity ions in the filtrate, improving the overall quality of the filtrate entering fine filtration, especially extraction. Fine filtration aid is reduced by more than 50%, phase separation during extraction is significantly accelerated, organic phase emulsification is significantly reduced, the production of three-phase materials is reduced by more than 60%, and organic phase loss is reduced by more than 30%.

[0032] 3. In the method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution provided by the present invention, the molybdenum heteropolyacid salts formed during the static aging process of the filtrate and the precipitates formed by coupling with fine mineral sands accumulate over a long period of time, with the dry basis molybdenum grade reaching more than 4%, resulting in high recovery value. By adding sodium carbonate to the precipitate and heating for alkaline leaching, the molybdenum metal can be transferred to the solution for modification, and then the molybdenum metal can be recovered by extraction, with a recovery rate of more than 90%. The overall filtrate purification process achieves minimal metal loss and substantial and effective treatment of the precipitate. Attached Figure Description

[0033] Figure 1 This is a flowchart of a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution provided by the present invention. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0035] like Figure 1 As shown, the present invention provides a method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution, which specifically includes the following steps:

[0036] Step 1: The uranium-molybdenum ore slurry is subjected to oxygen pressure leaching at a temperature of 162±1℃, a pressure of ≤0.95Mpa, and an oxygen partial pressure of ≤40%. It is then discharged into a flash tank to cool and depressurize, so that the slurry temperature is reduced to below 70℃ and the pressure is reduced to 0.02-0.08Mpa. After being buffered in an atmospheric pressure intermediate tank, it is pumped into a modified cooling tank and 20-30% of calcium carbide slag slurry is added to obtain a post-leaching slurry with an acidity of 20-40g / l and a temperature below 80℃.

[0037] Step 2: Add acidic flocculant to the slurry after leaching in Step 1, mix rapidly, and then filter to achieve solid-liquid separation. Filter out the slurry filtrate with a turbidity of 200ppm-500ppm. The solid tailings are stored in a tailings silo. The acidic flocculant is a mixture of FZ3802, 25xv, 25s, 25v, or higher flocculants; the flocculant-to-water ratio is 1:1000 by weight; the flocculant dosage is 50-100 mg / L. 3 Add 1-3m of leaching pulp 3 Flocculants.

[0038] Step 3: Add acidic flocculant to the filtrate after filtration in Step 2 and stir to thicken. Fine mineral sands will agglomerate under the action of the flocculant, continuously forming large molecular chains. Under gravity, they will sink to the bottom, forming a low-concentration slurry. The flocculent sand at the bottom is pumped to the leached slurry in Step 2 for mixing and filtration. During the thickening process, the stirring speed of the thickening equipment is 3-5 min / r (too fast a stirring speed will damage the large molecular chains of the flocculant, resulting in loss of flocculation). The supernatant from the thickening process overflows into the potential regulating tank, obtaining an overflow filtrate with a turbidity of 80-100 ppm. The acidic flocculant is a mixture of FZ3802, 25xv, 25s, 25v, or higher flocculants. The flocculant ratio is 1:1000 by weight of flocculant to water. The flocculant dosage is 50-80 mg / L. 3 Add 0.2-0.5 mg of the filtered mineral slurry filtrate. 3 Flocculants.

[0039] Step 4: Add hydrogen peroxide to the potential adjustment tank in step 3 to adjust the potential. Control the potential of the filtrate from -450mV to -480mV using a potentiometer to obtain the potential-adjusted filtrate.

[0040] Step 5: Pump the filtrate after potential adjustment in step 4 into the clarification facility and let it stand for 24 hours to obtain the filtrate and precipitate after standing and aging.

[0041] Step 6: Filter the filtrate after step 5 by passing it through a 3-5 cm thick layer of diatomaceous earth attached to a vacuum drum. The filter aid is diatomaceous earth or a mixture of diatomaceous earth and perlite. The filtrate after fine filtration is obtained, and the turbidity of the finely filtered filtrate is reduced to 20-50 ppm.

[0042] Step 7: Cool the filtrate after fine filtration in Step 6 through a cooling device to 25-32°C. The resulting purified filtrate is then used in the downstream extraction process.

[0043] Step 8: Collect the precipitate after settling and aging in Step 5. The precipitate contains 70%-85% water, and its main components and contents on a dry basis are: Mo: 3%-5%, SO42-: 30%-35%, Ca: 20%-25%, Si: 6%-10%, As: 2%-5%, Fe: 2%-5%, Al: 5%-8%. After drying, the precipitate appears white with a white surface layer containing fine mineral sand solids. Add clean water (or treated neutral hydrometallurgical system water) to the precipitate at a volume ratio of 1:1 and stir to mix. Add sodium carbonate to adjust the pH to 9.5-10, raise the temperature to 60℃, and continue stirring for 30 minutes. After stirring, wash and filter to obtain a filter cake and an alkaline leaching filtrate. Recover molybdenum metal from the filter cake and alkaline leaching filtrate. The Mo grade in the filter cake should be below 0.2%. The Mo concentration in the alkaline leaching filtrate should be 5-10 g / L. The molybdenum recovery rate reached over 92%.

[0044] Step 9: Add acid to the filtrate after alkaline leaching in Step 8 to adjust the pH to 2-3, and then extract using an extractant; or mix the purified filtrate from Step 7 with the filtrate after alkaline leaching in Step 8, add acid to adjust the pH to 2-3, and then extract using an extractant. Molybdenum metal is recovered after extraction. The extractant is an organic phase extractant formed by mixing tertiary amine extractant, acidic organophosphorus co-extractant, and sulfonated kerosene in a volume ratio of 6.5%, 15%, and 78.5%. After extraction, the Mo concentration in the raffinate water is below 0.05 g / L.

[0045] The method of this invention effectively reduces the solid content of the filtrate before fine filtration and the concentration of impurity ions in the extraction solution. The efficiency of static aging and fine filtration is significantly improved, and the amount of fine filtration aid is reduced by more than 50%. Phase separation during extraction is significantly accelerated, organic phase emulsification is reduced, the amount of three-phase material generated is reduced by more than 60%, and the loss of organic phase is reduced by more than 30%. By alkali leaching the impurity precipitates generated during filtrate aging (under the same alkalinity conditions, alkali leaching effect: sodium carbonate ≥ sodium hydroxide ≥ ammonia), the alkali leaching Mo leaching rate is ≥92%, and the comprehensive Mo recovery rate is ≥90%, achieving the recycling and reuse of molybdenum metal and increasing the added value of enterprises.

[0046] Example 1:

[0047] Taking the uranium-molybdenum ore leachate obtained by recovering uranium-molybdenum metal using oxygen pressure acid leaching technology from a certain uranium-molybdenum ore (molybdenum grade 0.8%, uranium grade 0.06%) as an example, this invention provides a method for purifying uranium-molybdenum ore leachate and recovering molybdenum metal from impurities. The specific steps are as follows:

[0048] Step 1: Oxygen pressure leaching uses ore with a particle size of -100 mesh and a daily processing capacity of 570 t / d dry ore.

[0049] After uranium-molybdenum ore leaching at 162±1℃, ≤0.95Mpa, and ≤40% oxygen partial pressure for 1-1.5h, the ore slurry is discharged into a flash tank for cooling and depressurization, reducing the slurry temperature to below 70℃ and the pressure to 0.02-0.08Mpa. After being buffered in an atmospheric pressure intermediate tank, the slurry is pumped into a modified cooling tank and 20-30% calcium carbide slag slurry is added to obtain a post-leaching slurry with an acidity of 25g / l and a temperature of 70℃.

[0050] Step 2: Process the leaching slurry obtained in Step 1 according to the following steps: per 50m³ 3 Add 1m of slurry 3 The FZ3802+25XV mixed flocculant (flocculant concentration: flocculant to water weight ratio of 1:1000) is subjected to solid-liquid separation in a diaphragm plate and frame filter press. After two washings in the diaphragm plate and frame (to transfer the metal attached to the ore sand to the filtrate), the filter tailings are transported to the tailings storage. The turbidity of the resulting filtered slurry filtrate is 286ppm, and it proceeds to the next process.

[0051] Step 3: Mix the filtered slurry filtrate obtained in Step 2 with FZ3802+25XV mixed flocculant (per 50m³). 3 Add 0.2 mg of flocculant to the filtrate. 3 The flocculant concentration is set at 1:1000 (flocculator to water weight ratio of 1:1000). This mixture is then fed into a deep cone thickener for thickening. During thickening, the agitation speed of the thickener is 3 min / r. In the thickener, fine mineral sands agglomerate under the action of the flocculant, continuously forming large molecular chains. Under gravity, these chains settle to the bottom, forming a low-concentration slurry, which is then pumped into step 2 for membrane filtration. The supernatant overflowing from the top of the thickener flows into a potential regulating tank, yielding overflow filtrate (turbidity 89 ppm), which proceeds to the next process.

[0052] Step 4: Add hydrogen peroxide to the potential adjustment tank to adjust the potential. Mix the overflow filtrate obtained in Step 3 with hydrogen peroxide to obtain a potential-adjusted filtrate with a potential of -455mV.

[0053] Step 5: Pour the potential-adjusted filtrate obtained in Step 4 into a clarification tank and let it stand for 24 hours to age, obtaining the aged filtrate and precipitate. After one month of continuous production, it will be in a total volume of 3000m³. 3 The bottom of the clarification pool is about 100m 3 The soft sediment.

[0054] Step 6: Filter the filtrate obtained in Step 5 after settling and aging through a vacuum drum filter (the filter aid is diatomaceous earth, and the air permeability of the drum filter cloth is 300 L / m). 2 After ·S), a finely filtered filtrate was obtained, with a turbidity of 26 ppm.

[0055] Step 7: After the finely filtered filtrate obtained in Step 6 is cooled to 30°C by a filtrate cooling device, the purified filtrate is then introduced into the extraction process for further processing.

[0056] Step 8: Collect the precipitate from step 5 after settling and aging into a 10m³ mixing tank. 3 (The precipitate contains 75% of the filtrate obtained in step 5, and its main components and contents on a dry basis are: Mo: 3.2%, SO42-: 33%, Ca: 22%, Si: 6.8%, As: 2.5%, Fe: 3.3%, Al: 6.2%). Add 10 ml of water at a volume ratio of 1:1 between the precipitate and the purified water. 3 Start stirring and add sodium carbonate to adjust the pH of the slurry to 9.6. Heat to 60°C with steam and stir continuously for 30 minutes to obtain the recovered slurry.

[0057] Step 9: Filter the recovered slurry obtained in Step 8 using a plate and frame filter press, and perform a 1m wash. 3 The material was then pressed and discharged to obtain a filter cake and an alkaline leaching filtrate. Analysis of the filter cake showed a dry basis molybdenum content of 0.16%, and the molybdenum concentration of the filtrate was 6.3 g / L.

[0058] Step 10: The filtrate obtained in Step 9 after alkaline leaching was adjusted to pH 2.8 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water after extraction was measured to be 0.04 g / L. Separately, a portion of the purified filtrate obtained in Step 7 was mixed with the filtrate obtained in Step 9. The pH was adjusted to 2.5 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water was 0.02 g / L.

[0059] After adopting the above process method:

[0060] (1) The turbidity of the uranium-molybdenum ore oxygen pressure acid leaching filtrate after the thickening process is reduced from 286ppm to 26ppm in the clarification tank, which alleviates the clarification space in the clarification tank; at the same time, the filtrate is thickened and then aged by potential regulation, which can cause a large amount of impurity ions that affect the extraction operation to precipitate out, improve the quality of the raw liquid entering the extraction, and improve the fine filtration and extraction operation quality and efficiency of the filtrate.

[0061] (2) Through data comparison, the consumption of fine filter aid diatomite per ton of ore before and after adopting this process method was 3.4 kg / t ore and 1.37 kg / t ore, respectively, and the consumption of filter aid was reduced by 59.7%.

[0062] (3) The organic phase extraction consumption per ton of ore before and after adopting this process method is 2.8 kg / t ore and 1.9 kg / t ore respectively, and the organic phase consumption is reduced by 32.1%.

[0063] (4) The extraction and phase separation are accelerated before and after using this process, the emulsification phenomenon is significantly reduced, and the production of three phases is greatly reduced from 1.35 tons per month to 0.5 tons, a reduction of 62.96%.

[0064] (5) By heating and alkali leaching the stagnant aged impurity metals, the Mo recovery rate in the sludge reached 95.8%, realizing efficient recovery of molybdenum metal from impurities, reducing the loss of molybdenum metal in this process, and further improving the utilization rate of molybdenum resources.

[0065] Example 2:

[0066] Taking the uranium-molybdenum ore leachate obtained by recovering uranium and molybdenum metals from a certain uranium-molybdenum symbiotic ore (molybdenum grade 0.88%, uranium grade 0.043%) using oxygen pressure acid leaching technology as an example, this invention provides a method for purifying uranium-molybdenum ore leachate and recovering molybdenum metal from impurities. The specific steps are as follows:

[0067] Step 1: Oxygen pressure leaching uses ore with a particle size of -100 mesh and a daily processing capacity of 600 t / d dry ore.

[0068] After leaching the uranium-molybdenum ore slurry at a temperature of 162±1℃, a pressure of ≤0.95Mpa, and an oxygen partial pressure of ≤40% for 1-1.5h, it is discharged into a flash tank to cool and depressurize, reducing the slurry temperature to below 70℃ and the pressure to 0.02-0.08Mpa. After being discharged into an atmospheric pressure intermediate tank for buffering, it is pumped into a modified cooling tank and 20-30% of calcium carbide slag slurry is added to obtain a post-leaching slurry with an acidity of 28g / l and a temperature of 72℃.

[0069] Step 2: Process the leaching slurry obtained in Step 1 according to the following steps: per 50m³ 3 Add 1m of slurry 3The 25s+25xv mixed flocculant (flocculant concentration: flocculant to water weight ratio of 1:1000) is subjected to solid-liquid separation in a diaphragm plate and frame filter press. After two washings in the diaphragm plate and frame (to transfer the metal attached to the ore sand to the filtrate), the filter tailings are transported to the tailings storage. The turbidity of the resulting filtered slurry filtrate is 271ppm, and it proceeds to the next process.

[0070] Step 3: Mix the filtered slurry filtrate obtained in Step 2 with a 25s+25xv mixed flocculant (per 50m³). 3 Add 0.2 mg of flocculant to the filtrate. 3 The flocculant concentration is set at 1:1000 (flocculator to water weight ratio of 1:1000). This mixture is then fed into a deep cone thickener for thickening. During thickening, the agitation speed of the thickener is 4 min / r. In the thickener, fine mineral sands agglomerate under the action of the flocculant, continuously forming large molecular chains. Under gravity, these chains settle to the bottom, forming a low-concentration slurry, which is then pumped into step 2 for membrane filtration. The supernatant overflowing from the top of the thickener flows into a potential regulating tank, yielding overflow filtrate (turbidity 76 ppm), which proceeds to the next process.

[0071] Step 4: Add hydrogen peroxide to the potential adjustment tank to adjust the potential. Mix the overflow filtrate obtained in Step 3 with hydrogen peroxide to obtain a potential-adjusted filtrate with a potential of -472mV.

[0072] Step 5: Pour the potential-adjusted filtrate obtained in Step 4 into a clarification tank and let it stand for 24 hours to age, obtaining the aged filtrate and precipitate. After one month of continuous production, it will be in a total volume of 3000m³. 3 The bottom of the clarification pool is about 100m 3 The soft sediment.

[0073] Step 6: Filter the filtrate obtained in Step 5 after settling and aging through a vacuum drum filter (the filter aid is diatomaceous earth, and the air permeability of the drum filter cloth is 300 L / m). 2 After ·S), a finely filtered filtrate was obtained, with a turbidity of 23 ppm.

[0074] Step 7: The finely filtered filtrate obtained in Step 6 is cooled to 32°C by a filtrate cooling device to obtain purified filtrate, which is then introduced into the extraction process for further processing.

[0075] Step 8: Collect the precipitate from step 5 after settling and aging into a 10m³ mixing tank. 3 (The precipitate contains 72% of the filtrate obtained in step 5. The main components and contents on a dry basis are: Mo: 4.1%, SO42-) 2-(Content: 36%, Ca: 21%, Si: 7.2%, As: 1.8%, Fe: 4.2%, Al: 5.3%), add 10ml of water at a precipitate-to-water volume ratio of 1:1. 3 Start stirring and add sodium carbonate to adjust the pH of the slurry to 9.4. Heat the slurry to 62°C with steam and stir continuously for 30 minutes to obtain the recovered slurry.

[0076] Step 9: Filter the recovered slurry obtained in Step 8 using a plate and frame filter press, and perform a 1m wash. 3 The material was then pressed and discharged to obtain a filter cake and an alkaline leaching filtrate. Analysis of the filter cake showed a dry basis molybdenum content of 0.19%, and the molybdenum concentration of the filtrate was 6.9 g / L.

[0077] Step 10: The filtrate obtained in Step 9 after alkaline leaching was adjusted to pH 2.7 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water after extraction was measured to be 0.05 g / L. Separately, a portion of the purified filtrate obtained in Step 7 was mixed with the filtrate obtained in Step 9. The pH was adjusted to 2.6 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water was 0.03 g / L.

[0078] After adopting the above process method:

[0079] (1) The turbidity of the uranium-molybdenum ore oxygen pressure acid leaching filtrate after the thickening process is reduced from 271ppm to 23ppm in the clarification tank, which alleviates the clarification space in the clarification tank; at the same time, the filtrate is thickened and then aged by potential regulation, which can cause a large amount of impurity ions that affect the extraction operation to precipitate out, improve the quality of the raw liquid entering the extraction, and improve the fine filtration and extraction operation quality and efficiency of the filtrate.

[0080] (2) Through data comparison, the consumption of fine filter aid diatomite per ton of ore before and after adopting this process method was 3.4 kg / t ore and 1.36 kg / t ore, respectively, and the consumption of filter aid was reduced by 60%.

[0081] (3) The organic phase extraction consumption per ton of ore before and after adopting this process method is 2.8 kg / t ore and 1.95 kg / t ore respectively, and the organic phase consumption is reduced by 30.35%.

[0082] (4) Using this process, the extraction and phase separation are accelerated, the emulsification phenomenon is significantly reduced, and the production of three phases is greatly reduced from 1.35 tons per month to 0.5 tons, a reduction of 62.9%.

[0083] (5) By heating and alkali leaching the stagnant aged impurity metals, the Mo recovery rate in the sludge reached 94.6%, realizing efficient recovery of molybdenum metal from impurities, reducing the loss of molybdenum metal in this process, and further improving the utilization rate of molybdenum resources.

[0084] Example 3:

[0085] Taking a uranium-molybdenum ore leaching process (0.69% molybdenum grade, 0.057% uranium grade) as an example, this invention provides a method for purifying and recovering molybdenum metal from impurities in the uranium-molybdenum ore leaching solution. The specific steps are as follows:

[0086] Step 1: Oxygen pressure leaching uses ore with a particle size of -100 mesh and a daily processing capacity of 630 t / d dry ore.

[0087] After leaching the uranium-molybdenum ore slurry at a temperature of 162±1℃, a pressure of ≤0.95Mpa, and an oxygen partial pressure of ≤40% for 1-1.5h, it is discharged into a flash tank to cool and depressurize, reducing the slurry temperature to below 70℃ and the pressure to 0.02-0.08Mpa. After being discharged into an atmospheric pressure intermediate tank for buffering, it is pumped into a modified cooling tank and 20-30% of calcium carbide slag slurry is added to obtain a post-leaching slurry with an acidity of 28g / l and a temperature of 75℃.

[0088] Step 2: Process the leaching slurry obtained in Step 1 according to the following steps: per 50m³ 3 Add 1m of slurry 3 The 25V+25XV mixed flocculant (flocculant concentration: flocculant to water weight ratio of 1:1000) is subjected to solid-liquid separation in a diaphragm plate and frame filter press. After two washings in the diaphragm plate and frame (to transfer the metal attached to the ore sand to the filtrate), the filter tailings are transported to the tailings storage. The turbidity of the filtered slurry filtrate is 238ppm, and it proceeds to the next process.

[0089] Step 3: Mix the filtered slurry filtrate obtained in Step 2 with a 25V+25XV mixed flocculant (per 50m³). 3 Add 0.2 mg of flocculant to the filtrate. 3 The flocculant concentration is set at 1:1000 (flocculator to water weight ratio of 1:1000). This mixture is then fed into a deep cone thickener for thickening. During thickening, the agitation speed of the thickener is 5 min / r. In the thickener, fine mineral sands agglomerate under the action of the flocculant, continuously forming large molecular chains. Under gravity, these chains settle to the bottom, forming a low-concentration slurry, which is then pumped into step 2 for membrane filtration. The supernatant overflowing from the top of the thickener flows into a potential regulating tank, yielding overflow filtrate (turbidity 81 ppm), which proceeds to the next process.

[0090] Step 4: Add hydrogen peroxide to the potential adjustment tank to adjust the potential. Mix the overflow filtrate obtained in Step 3 with hydrogen peroxide to obtain a potential-adjusted filtrate with a potential of -483mV.

[0091] Step 5: Pour the potential-adjusted filtrate obtained in Step 4 into a clarification tank and let it stand for 24 hours to age, obtaining the aged filtrate and precipitate. After one month of continuous production, it will be in a total volume of 3000m³. 3 The bottom of the clarification pool is about 100m 3 The soft sediment.

[0092] Step 6: Filter the filtrate obtained in Step 5 after settling and aging through a vacuum drum filter (the filter aid is diatomaceous earth, and the air permeability of the drum filter cloth is 300 L / m). 2 After ·S), a finely filtered filtrate was obtained, with a turbidity of 20 ppm.

[0093] Step 7: After the finely filtered filtrate obtained in Step 6 is cooled to 30°C by a filtrate cooling device, the purified filtrate is then introduced into the extraction process for further processing.

[0094] Step 8: Collect the precipitate from step 5 after settling and aging into a 10m³ mixing tank. 3 (The precipitate contains 78% of the filtrate obtained in step 5. The main components and contents on a dry basis are: Mo: 3.8%, SO42-3.8%.) 2- (Content: 34%, Ca: 26%, Si: 6.3%, As: 2.3%, Fe: 3.8%, Al: 6.4%), add 10ml of water at a precipitate-to-water volume ratio of 1:1. 3 Start stirring and add sodium carbonate to adjust the pH of the slurry to 9.5. Heat to 60°C with steam and stir continuously for 30 minutes to obtain the recycled slurry;

[0095] Step 9: Filter the recovered slurry obtained in Step 8 using a plate and frame filter press, and perform a 1m wash. 3 The material was then pressed and discharged to obtain a filter cake and an alkaline leaching filtrate. Analysis of the filter cake showed a dry basis molybdenum content of 0.18%, and the molybdenum concentration of the filtrate was 5.6 g / L.

[0096] Step 10: The filtrate obtained in Step 9 after alkaline leaching was adjusted to pH 2.9 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water after extraction was measured to be 0.05 g / L. Separately, a portion of the purified filtrate obtained in Step 7 was mixed with the filtrate obtained in Step 9. The pH was adjusted to 2.4 by adding concentrated sulfuric acid. Molybdenum metal was then extracted using an organic phase formed by mixing TFA, TBP, and sulfonated kerosene in a ratio of 6.5%, 15%, and 78.5%, respectively. The molybdenum concentration in the raffinate water was 0.03 g / L.

[0097] After adopting the above process method:

[0098] (1) The turbidity of the uranium-molybdenum ore oxygen pressure acid leaching filtrate after the thickening process is reduced from 238 ppm to 20 ppm in the clarification tank, which alleviates the clarification space in the clarification tank; at the same time, after the filtrate is thickened, it is subjected to potential regulation and aging, which can cause a large amount of impurity ions that affect the extraction operation to precipitate out, improve the quality of the raw liquid entering the extraction, and improve the fine filtration and extraction operation quality and efficiency of the filtrate.

[0099] (2) Through data comparison, the consumption of fine filter aid diatomite per ton of ore before and after adopting this process method was 3.4 kg / t ore and 1.46 kg / t ore, respectively, and the consumption of filter aid was reduced by 57.1%.

[0100] (3) The organic phase extraction consumption per ton of ore before and after adopting this process method is 2.8 kg / t ore and 1.8 kg / t ore respectively, and the organic phase consumption is reduced by 35.7%.

[0101] (4) Using this process, the extraction and phase separation are accelerated, the emulsification phenomenon is significantly reduced, and the production of three phases is greatly reduced from 1.35 tons per month to 0.4 tons, a reduction of 70.3%.

[0102] (5) By heating and alkali leaching the stationary aged impurity metals, the Mo recovery rate in the sludge reached 95.26%, realizing efficient recovery of molybdenum metal from impurities, reducing the loss of molybdenum metal in this process, and further improving the utilization rate of molybdenum resources.

[0103] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. A method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution, characterized in that, The method includes: Step 1: The uranium-molybdenum ore slurry is subjected to oxygen pressure leaching, flash evaporation to reduce temperature and pressure, and back-end cooling to obtain the leached ore slurry; Step 2: Add acidic flocculant to the slurry after soaking in Step 1, mix quickly, and then filter to obtain the filtered slurry filtrate. Step 3: Add acidic flocculant to the slurry filtrate after filtration in Step 2, stir and thicken, transport the bottom flocculent ore sand to the leaching slurry in Step 2, mix and filter, and overflow the thickened supernatant into the potential regulating tank to obtain overflow filtrate. Step 4: Add hydrogen peroxide to the potential adjustment tank in step 3 to adjust the potential. Control the potential of the filtrate with a potentiometer to obtain the filtrate after potential adjustment. Step 5: Pump the filtrate after potential adjustment in Step 4 into the clarification facility and let it stand for aging to obtain the filtrate and precipitate after standing for aging. Step 6: Filter the filtrate after step 5 (after standing and aging) through a fine filtration device to obtain finely filtered filtrate. Step 7: Cool the filtrate after fine filtration in Step 6 through a cooling device to obtain purified filtrate, which is then used in the downstream extraction process. Step 8: Collect the precipitate after settling and aging in Step 5, add water to the precipitate and stir to mix, add sodium carbonate to adjust the pH value, heat up, continue stirring and then wash and filter to obtain filter cake and alkali leaching filtrate, and recover molybdenum metal from the filter cake and alkali leaching filtrate. Step 9: Add acid to the filtrate after alkaline leaching in Step 8 to adjust the pH value, and then extract with an extractant; or mix the purified filtrate from Step 7 with the filtrate after alkaline leaching in Step 8, add acid to adjust the pH value, and then extract with an extractant to recover molybdenum metal after extraction.

2. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The conditions for oxygen pressure leaching in step 1 are: temperature 162±1℃, pressure ≤0.95Mpa, oxygen partial pressure ≤40%, and oxygen pressure leaching time 1-1.5h; the conditions for flash evaporation cooling and depressurization are: temperature reduced to below 70℃, pressure reduced to 0.02-0.08Mpa; and the conditions for post-cooling are: addition of 20-30% carbide slag slurry, resulting in a post-leaching slurry acidity of 20-40g / l and a temperature below 80℃.

3. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The acidic flocculant in steps 2 and 3 is a mixture of flocculants such as FZ3802, 25xv, 25s, 25v or higher, and the ratio of flocculant to water is 1:1000 by weight.

4. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The amount of flocculant added in step 2 is 50-100 mg / L. 3 Add 1-3m of leaching pulp 3 The flocculant produced a turbidity of 200ppm-500ppm in the filtered slurry.

5. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The amount of flocculant added in step 3 is 50-80 mg / L. 3 Add 0.2-0.5 mg of the filtered mineral slurry filtrate. 3 The flocculant is used, and the thickening process involves stirring the equipment at a speed of 3-5 min / r. The turbidity of the overflow filtrate is 80-100 ppm.

6. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, In step 4, the potential adjustment process involves controlling the filtrate potential from -450mV to -480mV using a potentiometer.

7. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The aging time in step 5 is 24 hours.

8. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, In step 6, the fine filtration device is a vacuum drum filter, and the filter aid for fine filtration is diatomaceous earth or a mixture of diatomaceous earth and perlite. The turbidity of the filtrate after fine filtration is reduced to 20-50 ppm.

9. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, The cooling temperature in step 7 is 25-32℃.

10. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, In step 8, the volume ratio of precipitate to water is 1:1, sodium carbonate is added to adjust the pH to 9.5-10, the temperature is raised to 60℃, and the stirring time is 30 minutes.

11. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, In step 9, acid is added to adjust the pH value to 2-3.

12. The method for purifying and recovering molybdenum metal from impurities in uranium-molybdenum ore leaching solution according to claim 1, characterized in that, In step 9, the extractant is an organic phase extractant formed by mixing tertiary amine extractant, acidic organophosphorus synergistic extractant, and sulfonated kerosene in a volume ratio of 6.5%, 15%, and 78.5%.

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