A high-efficiency comprehensive recovery and smelting method for low-grade tungsten and molybdenum ore

Abstract

The invention discloses a high-efficiency comprehensive recovery and smelting method for low-grade tungsten-molybdenum ore, which belongs to the field of tungsten-molybdenum metallurgy technology, including: grinding the ore to 40-80% of -0.074mm, making a 30-50% concentration slurry; adding sodium carbonate to adjust the pH to 8-10, using dodecyl mercaptan and oleic acid mixed flotation to obtain a tungsten-molybdenum mixed concentrate; passing the concentrate slurry through oxygen pressure oxidation at 120-150°C and 0.5-2.0MPa for 1-5h; filtering the filtrate and extracting and separating it to obtain ammonium molybdate and ammonium tungstate products. This method effectively solves the technical problems of low flotation recovery of tungsten-molybdenum ore, difficulty in obtaining tungsten and molybdenum concentrate products by flotation, and large amounts of tungsten and molybdenum resources being wasted or unable to be effectively developed.

Description

Technical Field

[0001] The invention belongs to the technical field of tungsten and molybdenum metallurgy, and relates to a high-efficiency comprehensive recovery and smelting method for low-grade tungsten and molybdenum ores. Background Art

[0002] Molybdenum minerals occur primarily in the forms of molybdenite, schistose, and schistose. Tungsten minerals primarily consist of scheelite and wolframite. Currently, the beneficiation processes for molybdenite, scheelite, and wolframite are mature, achieving excellent beneficiation and smelting performance. Numerous refractory tungsten and molybdenum ores also exist in nature. Molybdenum in these ores primarily consists of schistose and schistose, with a relatively low proportion of molybdenite. Tungsten primarily occurs as fine-grained scheelite. The ores also contain significant amounts of gangue minerals such as talc and chlorite. These gangue minerals float and absorb reagents during the flotation of molybdenum and tungsten, resulting in poor flotation recoveries and concentrate grades for these ores. These ores currently utilize a preferential flotation process, whereby molybdenite is first floated to produce a low-grade molybdenum concentrate. The tailings from the molybdenite flotation are then subjected to flotation of schistose and schistose to produce a low-grade tungsten-molybdenum mixed concentrate. Using this process, the resulting low-grade molybdenum concentrate has a molybdenum grade of approximately 20%, while the resulting tungsten-molybdenum mixed concentrate has a tungsten grade of approximately 20% and a molybdenum grade of approximately 5%. The total flotation recovery of molybdenum is less than 50%, and the total flotation recovery of tungsten is less than 40%. The resulting molybdenum and tungsten concentrates do not meet smelting requirements and can only be processed as auxiliary materials for the smelting of high-quality molybdenum and tungsten concentrates, resulting in a significant waste of molybdenum and tungsten resources.

[0003] CN115970871A discloses a method for the comprehensive recovery of low-grade tungsten, molybdenum, and bismuth. The method includes the following steps: grinding the raw ore to a fineness sufficient to dissociate the basic monomers of the target minerals before separation, then flotating the sulfide minerals to obtain a coarse molybdenum-bismuth concentrate; then utilizing molybdenum's natural floatability to separate the molybdenum and bismuth, and subjecting the sulfide tailings to tungsten flotation to obtain a coarse tungsten concentrate. This technical solution still utilizes two flotations and requires the addition of a costly modified hydroxyapatite composite carbon nanotube agent as an auxiliary agent.

[0004] CN116837232A discloses a combined inhibitor and method for recovering scheelite from ultra-low-grade tungsten-molybdenum associated ore. The combined inhibitor comprises sodium humate, sodium thioglycolate, ammonium citrate, sodium pyrophosphate, sodium fluorosilicate, and lead nitrate, with these six substances configured in a ratio of 1:1:(2-5):(1-5):(1-3):(2-5). This technical solution targets molybdenum tailings slurry from ultra-low-grade tungsten-molybdenum associated ore, employing a process that first flots molybdenite, followed by tungsten-molybdenite and scheelite.

[0005] CN120041688A discloses a method for extracting tungsten and molybdenum from low-grade tungsten-molybdenum ore. The method involves leaching the low-grade tungsten-molybdenum ore with sulfuric acid, followed by solid-liquid separation to produce a leachate and a leach residue. Molybdenum is extracted from the leachate using a cationic extractant to produce a tungsten-containing molybdenum-extracted residual solution and a molybdenum-negative organic phase. Tungsten is then extracted from the tungsten-containing molybdenum-extracted residual solution using a neutral extractant to produce a tungsten-extracted residual solution and a tungsten-negative organic phase. This technical solution is targeted at tungsten-molybdenum ores with a (Mo + WO3) content of 5% to 30% after beneficiation.

[0006] There is an urgent need to develop an efficient comprehensive recovery and smelting method for low-grade tungsten and molybdenum ores to improve the recovery rate of tungsten and molybdenum resources and production efficiency. Summary of the Invention

[0007] The present invention aims to provide a highly efficient and comprehensive recovery and smelting method for low-grade tungsten-molybdenum ore. Addressing the shortcomings of existing technologies, this method utilizes a novel flotation collector system to separate and enrich tungsten-molybdenum-containing minerals such as molybdenite, tungstenite, scheelite, and wolframite from gangue minerals through a mixed flotation process, yielding a tungsten-molybdenum mixed concentrate and maximizing the flotation recovery rate of the tungsten-molybdenum minerals. During the flotation phase, the slurry pH is maintained at 8-10. The resulting mixed concentrate slurry undergoes a pressurized oxidation process, efficiently leaching the tungsten and molybdenum from the mixed concentrate into a leachate. The tungsten and molybdenum are then separated through an extraction process to produce tungsten-molybdenum chemical products such as ammonium molybdate and ammonium tungstate. This smelting method effectively addresses the technical challenges of low flotation recovery rates for tungsten-molybdenum ores, the difficulty in obtaining tungsten and molybdenum concentrate products, and the resulting waste or ineffective development of significant tungsten and molybdenum resources. This objective is achieved through the following specific technical solutions.

[0008] A high-efficiency comprehensive recovery and smelting method for low-grade tungsten and molybdenum ores comprises the following steps:

[0009] Step 1: Grind the low-grade tungsten and molybdenum ore to a suitable particle size to produce a slurry of a certain concentration;

[0010] Step 2: adding the ore pulp to a flotation machine, adding sodium carbonate as a pH adjuster to the ore pulp, adding dodecyl mercaptan and oleic acid as flotation collectors, and performing tungsten-molybdenum mixed flotation to obtain a tungsten-molybdenum mixed concentrate slurry containing molybdenite, tungstenite and scheelite;

[0011] Step 3: Add the tungsten-molybdenum mixed concentrate slurry into the reactor, heat it to the reaction temperature, introduce oxygen and keep it warm. After the reaction time is up, the reaction is completed and the slurry is cooled;

[0012] Step 4: After cooling, filtering is performed, and the filtrate is subjected to extraction and separation to obtain ammonium molybdate and ammonium tungstate products respectively.

[0013] The present invention provides a high-efficiency comprehensive recovery and smelting method for low-grade tungsten-molybdenum ore. By innovating the flotation collector system and combining mixed flotation with subsequent pressurized oxidation and extraction processes, the method achieves high-efficiency comprehensive recovery of tungsten and molybdenum from low-grade tungsten-molybdenum ore, solving the technical problems of low recovery rate and large amount of tungsten and molybdenum resources wasted in traditional processes.

[0014] Furthermore, in step 1, the low-grade tungsten and molybdenum ore is ground to a particle size of -0.074mm (i.e., below 0.074mm), accounting for 40-80%. This particle size range ensures the complete dissociation of the tungsten and molybdenum minerals in the ore, while preventing the sliming of gangue minerals caused by over-grinding, thereby improving the efficiency of subsequent flotation.

[0015] Furthermore, the slurry concentration in step 1 is 30-50%. This concentration range ensures sufficient contact between the reagent and the mineral during the flotation process, while providing a suitable solid-liquid ratio for the subsequent pressurized oxidation reaction, thereby improving the leaching effect.

[0016] Furthermore, the low-grade tungsten-molybdenum ore in step 1 has a tungsten content of 0.08-0.35 wt%, and a molybdenum content of 0.06-0.25 wt%.

[0017] Furthermore, the amount of sodium carbonate added in step 2 makes the pH value of the slurry 8-10. This pH range not only enhances the selective adsorption of dodecyl mercaptan and oleic acid on tungsten and molybdenum minerals, but also provides an alkaline environment for the pressurized oxidation reaction, promoting efficient leaching of tungsten and molybdenum.

[0018] Furthermore, in step 2, the mass ratio of dodecyl mercaptan to oleic acid is 1:1 to 3:1, and the flotation collector (the sum of dodecyl mercaptan and oleic acid) is used in an amount of 20 to 200 g / t of dry ore. A reasonable ratio and flotation collector dosage can synergistically enhance the capture capacity of various minerals such as molybdenite, tungstenite, and scheelite, thereby increasing the enrichment rate of tungsten and molybdenum in the mixed concentrate.

[0019] Furthermore, the molybdenum content in the tungsten-molybdenum mixed concentrate slurry obtained in step 2 is 0.1-5wt%, and the tungsten content is 0.1-10wt%.

[0020] Furthermore, the reaction temperature in step 3 is 120-150° C. A suitable reaction temperature can promote the decomposition and dissolution of tungsten and molybdenum minerals while avoiding a surge in energy consumption caused by excessively high temperatures.

[0021] Furthermore, the reaction time in step 3 is 1 to 5 hours. An appropriate reaction time can ensure that the tungsten and molybdenum minerals are fully oxidized and leached. Shortening the reaction time can improve production efficiency, while extending the time can further increase the leaching rate, balancing efficiency and effect.

[0022] Furthermore, the pressure in the reactor in step 3 is 0.5-2.0 MPa. Appropriate reaction pressure can accelerate the oxidation reaction rate, promote the release of tungsten and molybdenum elements from the mineral lattice, and improve the leaching efficiency.

[0023] The present invention is based on the following principles:

[0024] The main molybdenum-containing minerals in low-grade tungsten-molybdenum ores are molybdenite, calamite, and tungsten-containing minerals, while tungsten-containing minerals are scheelite and wolframite. The ore is also associated with significant amounts of gangue minerals such as talc and chlorite. Traditional preferential flotation processes for these ores are difficult to produce qualified molybdenum and tungsten concentrates, and flotation recoveries are low. A mixed flotation process is employed: the ore is crushed to an appropriate particle size, sodium carbonate is added to adjust the slurry pH to 8-10, and dodecyl mercaptan and oleic acid are added as flotation collectors. Mixed flotation of the molybdenite, calamite, tungsten-containing minerals, scheelite, and wolframite in the ore is performed to separate these minerals from the gangue minerals and enrich them to produce a tungsten-molybdenum mixed concentrate. Since the slurry pH is 8-10, direct pressure oxidation allows the slurry to oxidize the molybdenum and tungsten in the slurry and release them into the leachate. After pressurized oxidation, the slurry undergoes solid-liquid separation, and tungsten and molybdenum enter the leachate. Tungsten and molybdenum are then efficiently separated through an extraction process to produce molybdenum and tungsten chemical products such as ammonium molybdate and ammonium tungstate. Using this process to treat low-grade tungsten and molybdenum ores can increase the overall recovery rates of molybdenum and tungsten by approximately 20 and 40 percentage points, respectively, and directly produce molybdenum and tungsten chemical products.

[0025] The present invention has the following advantages:

[0026] 1. The present invention performs mixed flotation on tungsten-molybdenum ore by adding dodecyl mercaptan and oleic acid as flotation collectors, and no longer performs tungsten and molybdenum flotation separation to obtain a tungsten-molybdenum mixed concentrate, which can effectively improve the flotation recovery rate of molybdenum and tungsten in the ore.

[0027] 2. In the present invention, sodium carbonate is added to adjust the pH value of the ore pulp to 8-10, which can improve the flotation recovery rate of tungsten and molybdenum minerals in the ore, and at the same time provide a suitable pH value for the next step of pressurized oxidation leaching of tungsten and molybdenum in the mixed concentrate pulp.

[0028] 3. This invention uses direct pressurized oxidation of flotation pulp to leach tungsten and molybdenum. Under suitable temperature and reaction time conditions, efficient leaching of tungsten and molybdenum can be achieved. The leachate is then separated from the tungsten and molybdenum through an extraction process to produce tungsten and molybdenum chemical products.

[0029] 4. The present invention's beneficiation and smelting method for tungsten-molybdenum ore can achieve efficient and comprehensive recovery of this type of ore. Compared with traditional flotation processes, the molybdenum recovery rate increases by approximately 40 percentage points, and the tungsten recovery rate increases by approximately 20 percentage points, while producing qualified tungsten and molybdenum chemical products. This method improves both the flotation recovery rate of tungsten-molybdenum ore and the product grade of this type of ore. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] The tungsten-molybdenum ore used in the examples contained the following components in weight percentages: Mo 0.06-0.25%, W 0.08-0.35%. The molybdenum-containing minerals were molybdenite, tungstenite, and tungstenite, accounting for 20-30%, 55-65%, and 15-25%, respectively. The tungsten-containing minerals were scheelite and wolframite, accounting for 75-85% and 15-25%, respectively. The dodecyl mercaptan, oleic acid, and extractant used in the examples were all commercially pure, while the sodium carbonate and other reagents were chemically pure. Example 1

[0032] Step 1: Grind 1 kg of tungsten-molybdenum ore to a particle size of -0.074 mm, accounting for 55% of the total particle size. Adjust the slurry concentration to 30%. The ore contains 0.12% Mo, comprised of 40% molybdenite, 50% tungstenite, and 10% molybdenum tungsten. The tungsten content is 0.20%, comprised of 85% scheelite and 15% wolframite.

[0033] Step 2: Pour the slurry into a flotation machine and add sodium carbonate to adjust the pH to 9. Dodecyl mercaptan and oleic acid are added in a 1:1 mass ratio. A flotation collector is used at a rate of 20g / t of dry ore. After thorough stirring and dispersion, flotation is performed. The resulting tungsten-molybdenum mixed concentrate slurry has a molybdenum grade of 3.8% and a tungsten grade of 4.5%. The flotation tailings have a molybdenum grade of 0.010% and a tungsten grade of 0.025%. The molybdenum flotation recovery rate is 91.67%, and the tungsten flotation recovery rate is 87.5%.

[0034] Step 3: Add the tungsten-molybdenum mixed concentrate slurry directly into the reactor, heat it to 135°C, introduce oxygen, set the pressure in the reactor to 2.0 MPa, keep the reaction warm for 4 hours, and cool it to room temperature.

[0035] Step 4: Filter the pressurized oxidation product from step 3, dry the filter cake, weigh it, and test its molybdenum and tungsten content. Add sulfuric acid and EDTA to the filtrate to adjust the pH to 2. Extract the molybdenum in the solution with 10% P204 and kerosene. The molybdenum-containing organic phase is stripped with ammonia to produce an ammonium molybdate solution, which is crystallized to obtain the ammonium molybdate product. Extract the remaining molybdenum solution with N235, octanol, and kerosene to extract tungsten. The tungsten-containing organic phase is stripped with ammonia to produce an ammonium tungstate solution, which is crystallized to obtain the ammonium tungstate product. This achieves separation of tungsten and molybdenum in the solution, and produces tungsten and molybdenum products, respectively.

[0036] Weighing and calculation show that the filter cake obtained in step 4 of this embodiment contains 0.1% molybdenum and 0.2% tungsten, resulting in a molybdenum leaching rate of 97.36% and a tungsten leaching rate of 95.56%. Comprehensive calculations show that the above method for treating tungsten-molybdenum ore has a total molybdenum recovery rate of 88.35% and a total tungsten recovery rate of 82.61%, achieving efficient and comprehensive recovery of difficult-to-separate tungsten-molybdenum ore.

[0037] The ore is processed by conventional preferential flotation process to obtain molybdenum concentrate with a molybdenum grade of 24% and a molybdenum recovery rate of 37%, and tungsten-molybdenum mixed concentrate with a tungsten grade of 18%, a molybdenum grade of 6% and a tungsten recovery rate of 55%.

[0038] Compared with the traditional preferential flotation process, the process provided by the present invention can increase the molybdenum recovery rate by 51.35 percentage points, the tungsten recovery rate by 27.61 percentage points, and obtain qualified molybdenum and tungsten chemical products. Example 2

[0039] Step 1: Grind 1 kg of tungsten-molybdenum ore to a particle size of -0.074 mm, accounting for 65% of the total. Adjust the slurry concentration to 45%. The ore has a Mo grade of 0.10%, consisting of 42% molybdenite, 55% tungstenite, and 3% tungsten sinter. The tungsten grade is 0.15%, consisting of 81% scheelite and 19% wolframite.

[0040] Step 2: Pour the ore pulp into a flotation machine and add sodium carbonate to adjust the pH value to 10. Add dodecyl mercaptan and oleic acid at a mass ratio of 2:1. Use 50g of flotation collector per ton of dry ore, stir thoroughly, and then flotate. The resulting tungsten-molybdenum mixed concentrate slurry has a molybdenum grade of 3.1% and a tungsten grade of 3.9%. The flotation tailings have a molybdenum grade of 0.009% and a tungsten grade of 0.018%. The molybdenum flotation recovery rate is 90.00%, and the tungsten flotation recovery rate is 88.00%.

[0041] Step 3: Add the tungsten-molybdenum mixed concentrate slurry directly into the reactor, heat it to 120°C, introduce oxygen, set the pressure in the reactor to 2.0 MPa, keep the reaction warm for 5 hours, and cool it to room temperature.

[0042] Step 4: Filter the pressurized oxidation product from step 3, dry the filter cake, weigh it, and test its molybdenum and tungsten content. Add sulfuric acid and EDTA to the filtrate to adjust the pH to 2. Extract the molybdenum in the solution with 10% P204 and kerosene. The molybdenum-containing organic phase is stripped with ammonia to produce an ammonium molybdate solution, which is crystallized to obtain the ammonium molybdate product. Extract the remaining molybdenum solution with N235, octanol, and kerosene to extract tungsten. The tungsten-containing organic phase is stripped with ammonia to produce an ammonium tungstate solution, which is crystallized to obtain the ammonium tungstate product. This achieves separation of tungsten and molybdenum in the solution, and produces tungsten and molybdenum products, respectively.

[0043] Weighing and calculation show that the filter cake obtained in step 4 of this embodiment contains 0.09% molybdenum and 0.17% tungsten, resulting in a molybdenum leaching rate of 97.10% and a tungsten leaching rate of 95.64%. Comprehensive calculations show that the above method for treating tungsten-molybdenum ore has a total molybdenum recovery rate of 87.39% and a total tungsten recovery rate of 84.96%, achieving efficient and comprehensive recovery of difficult-to-separate tungsten-molybdenum ore.

[0044] The ore is processed by traditional preferential flotation process to obtain molybdenum concentrate with a molybdenum grade of 22.45% and a molybdenum recovery rate of 39.55%, and tungsten-molybdenum mixed concentrate with a tungsten grade of 17.88%, a molybdenum grade of 3.21% and a tungsten recovery rate of 47.20%.

[0045] Compared with the traditional preferential flotation process, the process provided by the present invention can increase the molybdenum recovery rate by 47.84 percentage points, the tungsten recovery rate by 37.76 percentage points, and obtain qualified molybdenum and tungsten chemical products. Example 3

[0046] Step 1: Grind 1 kg of tungsten-molybdenum ore to a particle size of -0.074 mm, accounting for 75% of the total. Adjust the slurry concentration to 40%. The ore contains 0.20% Mo, comprised of 45% molybdenite, 45% tungstenite, and 10% molybdenum tungsten. The tungsten grade is 0.28%, comprised of 83% scheelite and 17% wolframite.

[0047] Step 2: Pour the ore pulp into a flotation machine and add sodium carbonate to adjust the pH to 9.5. Add dodecyl mercaptan and oleic acid in a 3:1 mass ratio. Use 100g of flotation collector per ton of dry ore. After thorough stirring and dispersion, flotation is performed. The result is a tungsten-molybdenum mixed concentrate with a molybdenum grade of 4.2% and a tungsten grade of 7.7%. The flotation tailings have a molybdenum grade of 0.019% and a tungsten grade of 0.031%. The molybdenum flotation recovery rate is 90.50%, and the tungsten flotation recovery rate is 88.93%.

[0048] Step 3: Add the tungsten-molybdenum mixed concentrate slurry directly into the reactor, heat it to 145°C, introduce oxygen, set the pressure in the reactor to 1.5MPa, keep the reaction warm for 3h, and cool it to room temperature.

[0049] Step 4: Filter the pressurized oxidation product from step 3, dry the filter cake, weigh it, and test its molybdenum and tungsten content. Add sulfuric acid and EDTA to the filtrate to adjust the pH to 2. Extract the molybdenum in the solution with 10% P204 and kerosene. The molybdenum-containing organic phase is stripped with ammonia to produce an ammonium molybdate solution, which is crystallized to obtain the ammonium molybdate product. Extract the remaining molybdenum solution with N235, octanol, and kerosene to extract tungsten. The tungsten-containing organic phase is stripped with ammonia to produce an ammonium tungstate solution, which is crystallized to obtain the ammonium tungstate product. This achieves separation of tungsten and molybdenum in the solution, and produces tungsten and molybdenum products, respectively.

[0050] Weighing and calculation show that the filter cake obtained in step 4 of this embodiment contains 0.15% molybdenum and 0.19% tungsten, resulting in a molybdenum leaching rate of 97.58% and a tungsten leaching rate of 97.53%. Comprehensive calculations show that the above method for treating tungsten-molybdenum ore has a total molybdenum recovery rate of 88.31% and a total tungsten recovery rate of 86.73%, achieving efficient and comprehensive recovery of difficult-to-separate tungsten-molybdenum ore.

[0051] The ore is processed by conventional preferential flotation process to obtain molybdenum concentrate with a molybdenum grade of 30.55% and a molybdenum recovery rate of 40.21%, and tungsten-molybdenum mixed concentrate with a tungsten grade of 26.72%, a molybdenum grade of 7.22% and a tungsten recovery rate of 60.83%.

[0052] Compared with the traditional preferential flotation process, the process provided by the present invention can increase the molybdenum recovery rate by 48.10 percentage points, the tungsten recovery rate by 25.90 percentage points, and obtain qualified molybdenum and tungsten chemical products. Example 4

[0053] Step 1: Grind 1 kg of tungsten-molybdenum ore to a particle size of -0.074 mm, accounting for 40% of the total particle size. Adjust the slurry concentration to 50%. The ore has a Mo grade of 0.18%, consisting of 55% molybdenite, 42% tungstenite, and 3% tungsten sinter. The tungsten grade is 0.15%, consisting of 75% scheelite and 25% wolframite.

[0054] Step 2: Pour the ore pulp into a flotation machine and add sodium carbonate to adjust the pH value to 9.5. Add dodecyl mercaptan and oleic acid in a mass ratio of 3:1. Use 180g / t of dry ore as a flotation collector. After thorough stirring and dispersion, flotation is performed. The resulting tungsten-molybdenum mixed concentrate slurry has a molybdenum grade of 4.7% and a tungsten grade of 6.2%. The flotation tailings have a molybdenum grade of 0.019% and a tungsten grade of 0.014%. The molybdenum flotation recovery rate is 89.44%, and the tungsten flotation recovery rate is 90.66%.

[0055] Step 3: Add the tungsten-molybdenum mixed concentrate slurry directly into the reactor, heat it to 150°C, introduce oxygen, set the pressure in the reactor to 2.0 MPa, keep the temperature for 1 hour, and cool it to room temperature.

[0056] Step 4: Filter the pressurized oxidation product from step 3, dry the filter cake, weigh it, and test its molybdenum and tungsten content. Add sulfuric acid and EDTA to the filtrate to adjust the pH to 2. Extract the molybdenum in the solution with 10% P204 and kerosene. The molybdenum-containing organic phase is stripped with ammonia to produce an ammonium molybdate solution, which is crystallized to obtain the ammonium molybdate product. Extract the remaining molybdenum solution with N235, octanol, and kerosene to extract tungsten. The tungsten-containing organic phase is stripped with ammonia to produce an ammonium tungstate solution, which is crystallized to obtain the ammonium tungstate product. This achieves separation of tungsten and molybdenum in the solution, and produces tungsten and molybdenum products, respectively.

[0057] Weighing and calculation show that the filter cake obtained in step 4 of this embodiment contains 0.15% molybdenum and 0.19% tungsten, resulting in a molybdenum leaching rate of 97.37% and a tungsten leaching rate of 96.94%. Comprehensive calculations show that the above method for treating tungsten-molybdenum ore has a total molybdenum recovery rate of 87.09% and a total tungsten recovery rate of 87.89%, achieving efficient and comprehensive recovery of difficult-to-separate tungsten-molybdenum ore.

[0058] The ore is processed by traditional preferential flotation process to obtain molybdenum concentrate with a molybdenum grade of 25.44% and a molybdenum recovery rate of 50.21%, and tungsten-molybdenum mixed concentrate with a tungsten grade of 17.89%, a molybdenum grade of 3.22% and a tungsten recovery rate of 59.42%.

[0059] Compared with the traditional preferential flotation process, the process provided by the present invention can increase the molybdenum recovery rate by 36.88 percentage points, the tungsten recovery rate by 28.43 percentage points, and obtain qualified molybdenum and tungsten chemical products. Example 5

[0060] Step 1: Grind 1 kg of tungsten-molybdenum ore to a particle size of -0.074 mm, accounting for 80% of the total particle size. Adjust the slurry concentration to 42%. The ore has a Mo grade of 0.17%, consisting of 50% molybdenite, 41% tungstenite, and 9% tungsten ore. The tungsten grade is 0.22%, consisting of 81% scheelite and 19% wolframite.

[0061] Step 2: Pour the ore pulp into a flotation machine and add sodium carbonate to adjust the pH to 8. Add dodecyl mercaptan and oleic acid at a mass ratio of 3:1. Use 200g / t of dry ore as a flotation collector. After thorough stirring and dispersion, flotation is performed. The resulting tungsten-molybdenum mixed concentrate slurry has a molybdenum grade of 3.2% and a tungsten grade of 7.5%. The flotation tailings have a molybdenum grade of 0.016% and a tungsten grade of 0.025%. The molybdenum flotation recovery rate is 90.59%, and the tungsten flotation recovery rate is 88.64%.

[0062] Step 3: Add the tungsten-molybdenum mixed concentrate slurry directly into the reactor, heat it to 140°C, set the pressure in the reactor to 0.5MPa, introduce oxygen, keep the temperature and react for 3h, and cool it to room temperature.

[0063] Step 4: Filter the pressurized oxidation product from step 3, dry the filter cake, weigh it, and test its molybdenum and tungsten content. Add sulfuric acid and EDTA to the filtrate to adjust the pH to 2. Extract the molybdenum in the solution with 10% P204 and kerosene. The molybdenum-containing organic phase is stripped with ammonia to produce an ammonium molybdate solution, which is crystallized to obtain the ammonium molybdate product. Extract the remaining molybdenum solution with N235, octanol, and kerosene to extract tungsten. The tungsten-containing organic phase is stripped with ammonia to produce an ammonium tungstate solution, which is crystallized to obtain the ammonium tungstate product. This achieves separation of tungsten and molybdenum in the solution, and produces tungsten and molybdenum products, respectively.

[0064] Weighing and calculation show that the filter cake obtained in step 4 of this embodiment contains 0.13% molybdenum and 0.42% tungsten, with a molybdenum leaching rate of 95.94% and a tungsten leaching rate of 94.40%. Comprehensive calculations show that the above method for treating tungsten-molybdenum ore has a total molybdenum recovery rate of 86.91% and a total tungsten recovery rate of 83.68%, achieving efficient and comprehensive recovery of difficult-to-separate tungsten-molybdenum ore.

[0065] The ore is processed by conventional preferential flotation process to obtain molybdenum concentrate with a molybdenum grade of 19.88% and a molybdenum recovery rate of 45.22%, and tungsten-molybdenum mixed concentrate with a tungsten grade of 28.45%, a molybdenum grade of 2.41% and a tungsten recovery rate of 58.76%.

[0066] Compared with the traditional preferential flotation process, the process provided by the present invention can increase the molybdenum recovery rate by 41.69 percentage points, the tungsten recovery rate by 24.92 percentage points, and obtain qualified molybdenum and tungsten chemical products.

[0067] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A high-efficiency comprehensive recovery and smelting method for low-grade tungsten and molybdenum ores, characterized in that: The following steps are involved: Step 1: Grind the low-grade tungsten and molybdenum ore to a suitable particle size to produce a slurry of a certain concentration; Step 2: adding the ore pulp to a flotation machine, adding sodium carbonate as a pH adjuster to the ore pulp, adding dodecyl mercaptan and oleic acid as flotation collectors, and performing tungsten-molybdenum mixed flotation to obtain a tungsten-molybdenum mixed concentrate slurry containing molybdenite, tungstenite and scheelite; Step 3: Add the tungsten-molybdenum mixed concentrate slurry into the reactor, heat it to the reaction temperature, introduce oxygen and keep it warm. After the reaction time is up, the reaction is completed and the slurry is cooled; Step 4: After cooling, filtering is performed, and the filtrate is subjected to extraction and separation to obtain ammonium molybdate and ammonium tungstate products respectively.

2. The method according to claim 1, characterized in that Step 1: Grind the low-grade tungsten and molybdenum ore to a particle size of -0.074mm, accounting for 40~80%.

3. The method according to claim 1, characterized in that The mass concentration of the slurry in step 1 is 30-50%.

4. The method according to claim 1, wherein The low-grade tungsten-molybdenum ore in step 1 has a tungsten content of 0.08-0.35wt% and a molybdenum content of 0.06-0.25wt%.

5. The method according to claim 1, wherein The amount of sodium carbonate added in step 2 is such that the pH value of the slurry is 8-10.

6. The method according to claim 1, characterized in that In step 2, the mass ratio of dodecyl mercaptan to oleic acid is 1:1-3:1, and the amount of flotation collector used is 20-200 g / t dry ore.

7. The method according to claim 1, characterized in that The molybdenum content in the tungsten-molybdenum mixed concentrate slurry obtained in step 2 is 0.1-5wt%, and the tungsten content is 0.1-10wt%.

8. The method according to claim 1, characterized in that The reaction temperature in step 3 is 120-150°C.

9. The method according to claim 1, characterized in that The reaction time in step 3 is 1 to 5 hours.

10. The method according to claim 1, characterized in that In step 3, the pressure in the reactor is 0.5~2.0MPa.