A method for efficient leaching of low-grade high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus and arsenic

Abstract

The present invention relates to the field of green smelting of tungsten ores, and particularly to a method for efficiently leaching low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ores and simultaneously fixing fluorine, phosphorus, and arsenic. This method first subjects the low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ores to ball milling activation and crushing; then uses sodium hydroxide-sodium carbonate as a decomposing agent and calcium oxide-magnesium sulfate-calcium chloride as a reagent for deeply fixing fluorine, phosphorus, and arsenic. Under hot pressing conditions, tungsten and molybdenum are efficiently leached, while simultaneously inhibiting the synchronous dissolution of fluorine, phosphorus, and arsenic; then through single-stage filtration and washing; then uses calcium oxide-magnesium oxide for deep purification to remove fluorine, phosphorus, and arsenic, and finally through two-stage filtration and washing to complete solid-liquid separation, obtaining a sodium tungstate-molybdate solution with low fluorine, low phosphorus, and low arsenic. This method solves the common key problems of the synchronous dissolution of fluorine, phosphorus, and arsenic during the leaching process, resulting in diffusion and migration throughout the process, causing great difficulty in deep purification and high disposal costs, from the source.

Description

Technical Field

[0001] The present invention relates to the field of green smelting of tungsten ore, and particularly to a method for efficiently leaching a low-grade high-fluorine high-arsenic high-phosphorus mixed tungsten ore and simultaneously fixing fluorine, phosphorus, and arsenic. Background Art

[0002] Tungsten, as an indispensable metal in the modern industrial system, its safe and efficient extraction technology has important practical significance for the modern industrial system. As the core base of global tungsten smelting, China undertakes more than 80% of the supply of tungsten products and occupies an irreplaceable position in the global tungsten industrial chain. However, with the continuous consumption of high-quality tungsten ore resources, the large-scale utilization of low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore has become a key issue for the sustainable development of the industry. Due to the composite phase structure of scheelite phase (CaWO4) and wolframite phase (Fe(Mn)WO4) in such minerals, and rich in harmful elements such as F (0.5% - 2.0%), P (2% - 8%), As (3% - 10%), etc., while containing valuable components such as WO3 (15% - 30%), Mo (2% - 10%) and Ca (10% - 20%), it belongs to a typical refractory resource with high impurities associated. Although its potential economic value is significant, the complex mineralogical characteristics lead to two core contradictions in traditional smelting processes: on the one hand, the phase difference between scheelite and wolframite results in low decomposition efficiency of the main metal, and the actual recovery rate of WO3 in the mineral has been at a low level for a long time; on the other hand, impurities such as fluorine, phosphorus, and arsenic are dissolved synchronously with tungsten and molybdenum during the decomposition process, forming a highly polluting leaching solution, forcing subsequent processes to add multiple purification systems, which not only greatly increases the consumption of acid and alkali and the cost of waste residue disposal, but also easily causes the risk of heavy metal pollution, seriously restricting the efficient and clean utilization of resources.

[0003] In view of the above technical bottlenecks, the existing processes for treating such minerals mainly have three categories: one is the high-fold alkali decomposition method, which can increase the leaching rate of tungsten and molybdenum to a certain extent, but requires 4 - 6 times the theoretical amount of alkali reagent, and the residual amount of WO3 in the decomposition residue still reaches 1.5% - 2.5%, and it fails to effectively inhibit the dissolution of fluorine, phosphorus, and arsenic; the second is the sodium carbonate decomposition method, which shows good decomposition effect on the scheelite phase, but the decomposition efficiency of the wolframite phase is significantly reduced, and it also cannot solve the problem of synchronous dissolution of pollutants; the third is the acid decomposition method, which not only has extremely low decomposition efficiency for the wolframite phase, but also causes a large amount of dissolution of fluorine, phosphorus, and arsenic in an acidic medium, forming a new pollution control problem.

[0004] In summary, the existing technologies are restricted by the dual constraints of mineral phase differences and impurity co-dissolution, and generally have defects such as low metal recovery rate, difficult pollutant control, and high comprehensive cost. How to construct a synergistic reaction system that selectively decomposes the main metal and directionally inhibits the dissolution of harmful elements has become the core research direction to break through the technical barriers of green smelting of low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore. Summary of the Invention

[0005] In order to break through the traditional treatment process of low-grade tungsten ore with high fluorine, high phosphorus and high arsenic, where fluorine, phosphorus and arsenic are easily dissolved synchronously, leading to the diffusion and migration of fluorine, phosphorus and arsenic pollutants throughout the process, resulting in difficult deep purification and high disposal costs, the present invention provides a method for efficiently leaching low-grade tungsten ore with high fluorine, high phosphorus and high arsenic while synchronously solidifying fluorine, phosphorus and arsenic.

[0006] By providing a method for efficiently leaching low-grade tungsten ore with high fluorine, high arsenic and high phosphorus while synchronously solidifying fluorine, phosphorus and arsenic, the embodiments of the present application solve the problems in the prior art that fluorine, phosphorus and arsenic are easily dissolved synchronously, resulting in the diffusion and migration of fluorine, phosphorus and arsenic pollutants throughout the process, difficult deep purification and high disposal costs. Tungsten and molybdenum are efficiently leached in the form of sodium tungstate and sodium molybdate, while the synchronous dissolution of fluorine, phosphorus and arsenic is inhibited, realizing the resource utilization of valuable metals tungsten and molybdenum while deeply solidifying fluorine, phosphorus and arsenic.

[0007] The embodiments of the present application provide a method for efficiently leaching low-grade tungsten ore with high fluorine, high arsenic and high phosphorus while synchronously solidifying fluorine, phosphorus and arsenic, and the steps are as follows:

[0008] S1. Ball milling activation and crushing: Weigh a certain amount of low-grade tungsten ore with high fluorine, high phosphorus and high arsenic, and carry out ball milling activation and crushing in a wet environment. After ball milling is completed, a mineral slurry is obtained and enters the next step.

[0009] S2. Hot pressure leaching while synchronously solidifying fluorine, phosphorus and arsenic: Add the mineral slurry, decomposing agent and deep fluorine, phosphorus and arsenic solidifying reagent obtained in step S1 into a decomposition kettle, carry out hot pressure leaching and synchronous fluorine, phosphorus and arsenic solidification. The composition of the decomposing agent is sodium carbonate - sodium hydroxide, and calcium oxide - magnesium sulfate - calcium chloride is used as the deep fluorine, phosphorus and arsenic solidifying reagent. After decomposition is completed, a decomposed hot slurry is obtained and enters the next step.

[0010] S3. First-stage filtration and washing: After step S2 is completed, filter and wash the decomposed hot slurry. First, filter the decomposed hot slurry to obtain a first-stage filtrate and a first-stage filter residue. Add hot tap water to the first-stage filter residue for primary washing, and mix the primary washing water and the first-stage filtrate to obtain a hot concentrated material, which is independently collected and processed in the next step. After the hot concentrated material is collected, wash it twice more. The first time, wash it with hot tap water, and collect the hot washing water separately and return it to step S1 for wet environment ball milling in the next time. Then, carry out secondary normal temperature tap water washing, and collect the normal temperature washing water for standby.

[0011] S4. Deep purification of fluorine, phosphorus and arsenic from the hot concentrated material: Add calcium oxide - magnesium oxide to the hot concentrated material obtained in step S3 and stir to carry out deep purification of fluorine, phosphorus and arsenic.

[0012] S5. Secondary filtration and washing: The slurry obtained in step S4 after deep purification to remove fluorine, phosphorus, and arsenic is subjected to secondary filtration and washing to obtain a sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic content. First, the slurry after deep purification to remove fluorine, phosphorus, and arsenic is filtered. After filtration is completed, secondary filtrate and secondary filter cake are obtained. The secondary filter cake is washed with normal temperature tap water. After mixing the secondary filtrate, secondary washing water, and the normal temperature washing water in step S3, a sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic content is obtained.

[0013] Sample and analyze the concentrations of fluorine, phosphorus, and arsenic in the sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic content, and the solidification rates of fluorine, phosphorus, and arsenic can be calculated.

[0014] As some embodiments of the present application, in step S1, the mass ratio of the water added during ball milling to the mass of the low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore added is 0.8:1 to 1:1, and the ball milling time is 10 min to 30 min.

[0015] As some embodiments of the present application, in step S1, after ball milling, the proportion of the mineral particle size -325 mesh is ≥97%, so as to ensure that the surface of the mineral is activated and the fine tungsten mineral particles wrapped are dissociated.

[0016] As some embodiments of the present application, in step S2, the total molar amount of the decomposition agent added is 3.0 to 5.0 times the theoretical molar amount when decomposed with sodium hydroxide alone.

[0017] As some embodiments of the present application, in step S2, the molar ratio of sodium hydroxide to sodium carbonate in the decomposition agent is 3:1 to 5:1.

[0018] As some embodiments of the present application, in step S2, the mass ratio of calcium oxide added to the original mass of the mineral is 1:20 to 1:5, the mass ratio of magnesium sulfate added to the original mass of the mineral is 1:40 to 1:20, and the mass ratio of calcium chloride added to the original mass of the mineral is 1:50 to 1:30.

[0019] As some embodiments of the present application, in step S2, the decomposition temperature is 150 °C to 220 °C, and the decomposition time is 3 h to 5 h.

[0020] As some embodiments of the present application, in step S3, the amount of hot tap water for the initial washing is 1 to 2 times the mass of the original mineral, and the temperature is 40 °C to 50 °C.

[0021] As some embodiments of the present application, in step S3, the water temperature for the first hot tap water washing is controlled at 40 °C to 50 °C, and the amount of washing water used is 1 to 2 times the mass of the original mineral.

[0022] As some embodiments of the present application, in step S3, the amount of washing water used for the secondary normal temperature tap water washing is 10 to 20 times the mass of the original mineral.

[0023] In some embodiments of the present application, in step S4, the stirring speed is controlled to be 60 r / min to 120 r / min, and the reaction time is 3 h to 6 h.

[0024] In some embodiments of the present application, in step S4, the total amount of calcium oxide - magnesium oxide added is 50 to 100 times the theoretical amount.

[0025] In some embodiments of the present application, in step S4, the molar ratio of calcium oxide to magnesium oxide is 3:1 to 5:1.

[0026] In some embodiments of the present application, in step S5, when washing the secondary filter residue with normal - temperature tap water, the washing is carried out until the soluble WO3 and soluble Mo in the residue are both less than 0.1%.

[0027] The process mechanism of the technical solution provided in the embodiments of the present application is as follows:

[0028] By ball - milling and activating and crushing the low - grade high - fluorine high - phosphorus high - arsenic mixed tungsten ore, a foundation is laid for the next - step efficient decomposition. Then, hot - pressure leaching is used to simultaneously fix fluorine, phosphorus, and arsenic. Using sodium hydroxide - sodium carbonate as the decomposing agent, it not only ensures that the scheelite phase (CaWO4) in the low - grade high - fluorine high - phosphorus high - arsenic mixed tungsten ore can be fully leached:

[0029] CaWO 4(S) +Na2CO 3(aq) →Na2WO 4(aq) +CaCO 3(S)

[0030] At the same time, it can efficiently decompose the wolframite phase (Fe(Mn)WO4). Meanwhile, the calcium oxide - magnesium sulfate - calcium chloride added synchronously is used as a deep - fluorine, phosphorus, and arsenic - fixing reagent, so that the dissolved F is solidified in the decomposition residue in the form of stable calcium fluorophosphate (Ca5(PO4)3F):

[0031] 5CaO (S) +5H2O - (aq) +F - (aq) +3PO4 3- (aq) →Ca5(PO4)3F (S) +10OH - (aq)

[0032] The dissolved P is solidified in the decomposition residue in the forms of stable calcium phosphate (Ca3(PO4)2) and magnesium phosphate (Mg3(PO4)2):

[0033] 3MgO (S) +3H2O(aq) +2PO4 3- (aq) →Mg3(PO4) 2(S) +6OH - (aq)

[0034] 3CaO (S) +3H2O+2PO4 3- (aq) →Ca3(PO4) 2(S) +6OH - (aq)

[0035] The dissolved As enters the slag in the form of insoluble calcium arsenate hydroxide [Ca3(AsO4)2·Ca(OH)2]:

[0036] 4CaO(S)+4H2O+2AsO4 3- (aq) →Ca3(AsO4)2·Ca(OH) 2(S) +6OH - (aq)

[0037] Using single-stage filtration and washing, the obtained hot concentrated material enters the next treatment step. The hot washing water is returned to the wet environmental ball milling step for recycling. The normal temperature washing water is used for the batching of the concentrated material after subsequent deep purification to remove fluorine, phosphorus, and arsenic. Then, deep purification to remove fluorine, phosphorus, and arsenic is carried out on the hot concentrated material. Using calcium oxide and magnesium oxide as reagents for deep removal of fluorine, phosphorus, and arsenic, and the presence of sodium carbonate in the solution environment can purify and remove fluorine, phosphorus, and arsenic to the greatest extent, while also inhibiting the coprecipitation of tungsten and molybdenum (the solubility products of calcium fluorophosphate, calcium phosphate, magnesium phosphate, and calcium arsenate hydroxide are all smaller than those of calcium tungstate and calcium molybdate, thereby achieving deep purification to remove fluorine, phosphorus, and arsenic, while inhibiting the secondary coprecipitation of tungsten and molybdenum and ensuring the recovery rate of target metals). Two-stage filtration and washing are carried out to separate the deep purification to remove fluorine, phosphorus, and arsenic slag from the sodium tungstate and molybdate solution with low fluorine, low phosphorus, and low arsenic. This method solves the common key problems at the source, such as the synchronous dissolution of fluorine, phosphorus, and arsenic during the leaching process of low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore, resulting in the diffusion and migration of fluorine, phosphorus, and arsenic pollutants throughout the process, causing great difficulty in deep purification and high disposal costs.

[0038] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0039] 1. Synchronously and efficiently fix fluorine, phosphorus, and arsenic to inhibit the diffusion of pollutants at the source: By using a combined reagent of calcium oxide - magnesium sulfate - calcium chloride in the hot - pressure leaching stage, the dissolved fluorine, phosphorus, and arsenic are respectively converted into stable compounds of calcium fluorophosphate, calcium phosphate, magnesium phosphate, and calcium basic arsenate, which are solidified in the slag, blocking their dissolution and migration at the source, and significantly reducing the subsequent purification difficulty and pollution risk.

[0040] 2. Significantly improve the leaching rates of tungsten and molybdenum to achieve resource utilization: By using a composite decomposing agent of sodium hydroxide - sodium carbonate and an optimized ball - milling activation process, the scheelite phase and wolframite phase are decomposed synchronously and efficiently, realizing the efficient leaching of tungsten and molybdenum, and effectively improving the utilization rate of low - grade tungsten ore resources.

[0041] 3. Low treatment cost and high applicability: By recycling the hot washing water to the ball - milling section and using the normal - temperature washing water and the purified concentrated material for batching, the consumption of tap water and chemical reagents is reduced; combined with segmented filtration washing and deep purification processes, the complexity of the traditional multi - stage purification process is avoided. By precisely controlling the process conditions and reagent ratios, the process stability and repeatability are ensured, and the strong adaptability of the method to complex ores is guaranteed to meet the requirements of industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for describing the specific embodiments or the prior art. Obviously, the drawings in the following description are only one embodiment of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 It is a schematic process flow diagram of an embodiment of the present invention. SPECIFIC EMBODIMENTS

[0044] In this application, an embodiment provides a method for efficiently leaching a low - grade high - fluorine high - phosphorus high - arsenic mixed tungsten ore and synchronously fixing fluorine, phosphorus, and arsenic, which solves the problems in the prior art that are generally restricted by the dual constraints of mineral phase differences and co - dissolution of impurities, and commonly have defects such as low metal recovery rate, difficult pollutant control, and high comprehensive cost. The general idea is as follows:

[0045] First, the low-grade tungsten ore with high fluorine, high phosphorus and high arsenic is ball-milled to activate and crush the mineral particles, and then hot-pressure leaching is carried out to simultaneously fix fluorine, phosphorus and arsenic. Sodium hydroxide-sodium carbonate is used as the decomposing agent, and calcium oxide-magnesium sulfate-calcium chloride is used as the reagent for deep fixation of fluorine, phosphorus and arsenic. Under hot-pressure conditions, tungsten and molybdenum are efficiently leached in the form of sodium tungstate and sodium molybdate, while the synchronous dissolution of fluorine, phosphorus and arsenic is inhibited. Thus, the resource utilization of valuable metals tungsten and molybdenum is realized, and at the same time, fluorine, phosphorus and arsenic are deeply solidified. Then, through first-stage filtration and washing, the solid-liquid separation of the thick slurry and the slag is completed. The hot thick slurry is deeply purified to remove fluorine, phosphorus and arsenic by using calcium oxide-magnesium oxide, and then through second-stage filtration and washing, the solid-liquid separation is completed to obtain a sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus and low arsenic.

[0046] In order to better understand the above technical solution, the following is a detailed description of the above technical solution in specific embodiments.

[0047] Example 1: This example is a method for efficient leaching of low-grade tungsten ore with high fluorine, high phosphorus and high arsenic and simultaneous fixation of fluorine, phosphorus and arsenic. The low-grade tungsten ore with high fluorine, high phosphorus and high arsenic used is provided by a mine in Hunan. The mineral is first subjected to sample preparation and then quantitatively analyzed by chemical methods. The results are as follows: F 0.64%, P 3.15%, As 4.89%, Ca 11.79%, WO3 17.15%, Mo 8.65%. As Figure 1 shown, the steps for efficient leaching of the low-grade tungsten ore with high fluorine, high phosphorus and high arsenic and simultaneous fixation of fluorine, phosphorus and arsenic by using the method of the present invention are as follows:

[0048] S1. Ball-milling activation and crushing: Weigh 500 g of the above-mentioned low-grade tungsten ore with high fluorine, high phosphorus and high arsenic, and carry out ball-milling activation and crushing in a wet environment. Control the mass ratio of the water added during ball-milling to the mass of the added low-grade tungsten ore with high fluorine, high phosphorus and high arsenic to be 1:1, and the ball-milling time to be 15 min. After ball-milling, the proportion of the mineral particle size -325 mesh in the mineral slurry is 98.15%.

[0049] S2. Simultaneous fixation of fluorine, phosphorus, and arsenic during hot-pressure leaching: Add the activated and crushed mineral slurry obtained in step S1 into a decomposition kettle (the inner volume of the decomposition kettle used in this example is 5000 ml), conduct hot-pressure leaching and simultaneous fixation of fluorine, phosphorus, and arsenic. Control the composition of the decomposing agent to be sodium carbonate - sodium hydroxide, and the total molar amount added is 4.0 times the theoretical molar amount when using sodium hydroxide alone for decomposition (calculation method: The total molar amount of WO3 and Mo in the mineral is 0.82 mol, where WO3 is 0.37 mol and Mo is 0.45 mol. If all are decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide is 1.64 mol. According to the condition, the designed total amount is 4 times the theory, so the total molar amount of sodium hydroxide is 6.56 mol, that is, the total molar amount of sodium carbonate - sodium hydroxide added is 6.56 mol), where the molar ratio of sodium hydroxide to sodium carbonate is 5:1 (then the amount of sodium hydroxide used is 5.47 mol, totaling 218.80 g; the amount of sodium carbonate used is 1.09 mol, totaling 115.54 g). Calcium oxide - magnesium sulfate - calcium chloride is used as a reagent for deep fixation of fluorine, phosphorus, and arsenic. The mass ratio of calcium oxide added to the original mass of the mineral is 1:20 (25 g of calcium oxide is added), the mass ratio of magnesium sulfate added to the original mass of the mineral is 1:40 (12.5 g of magnesium sulfate is added), and the mass ratio of calcium chloride added to the original mass of the mineral is 1:50 (10 g of calcium chloride is added). The decomposition temperature is 180 °C, and the decomposition time is 4 h. After decomposition is completed, decomposed hot slurry is obtained.

[0050] S3. First-stage filtration and washing: After step S2 is completed, the decomposed hot pulp is filtered and washed. First, the decomposed hot pulp is filtered to obtain first-stage filtrate and first-stage filter residue. After filtration is completed, hot tap water (at a temperature of 40°C and a volume of 1000 ml) twice the original mass of the mineral is added for primary washing. The primary washing water and the first-stage filtrate are mixed to obtain hot concentrated material, which is independently collected. After testing, the volume of the collected hot concentrated material is 1265 ml (F 5.18 mg / L, P 42.68 mg / L, As 36.78 mg / L). After the hot concentrated material is collected, it is washed twice more. The first time is washed with hot tap water at a temperature of 40°C, and the amount of washing water used is 1 times the original mass of the mineral (500 ml). The hot washing water is collected separately and returned to the next step S1 for ball milling. Then, it is washed with normal-temperature tap water for the second time, and the amount of washing water used is 10 times the original mass of the mineral (5000 ml). The soluble WO3 and soluble Mo in the washed residue are controlled to be less than 0.1%. The normal-temperature washing water (after testing, its total volume is 4915 ml, F 0.5 mg / L, P 0.4 mg / L, As 0.11 mg / L) is collected for standby. The washed residue is dried and weighed to be 408.75 g. The sampling test results are F 0.78%, P 3.84%, As 5.97%, WO3 0.68%, Mo 0.31%. The synchronous solidification rates of fluorine, phosphorus, and arsenic are calculated to be 99.63%, 99.54%, and 99.80% respectively, and the leaching rates of WO3 and Mo are 96.76% and 97.07% respectively.

[0051] S4. Deep purification of fluorine, phosphorus, and arsenic from hot concentrated material: Calcium oxide-magnesium oxide is added to the hot concentrated material obtained in step S3 for deep purification of fluorine, phosphorus, and arsenic. The stirring speed is controlled at 60 r / min, and the reaction time is 6 h. The total amount of calcium oxide-magnesium oxide added is 60 times the theoretical amount (calculation method: the total number of moles of fluorine, phosphorus, and arsenic in the hot concentrated material is 0.0027 mol, of which fluorine is 0.00034 mol, phosphorus is 0.00174 mol, and arsenic is 0.00062 mol. According to the dominant reaction mechanism, if all calcium oxide or magnesium oxide is used, the total required amount of calcium oxide or magnesium oxide is 0.2412 mol). The molar ratio of calcium oxide to magnesium oxide is 5:1 (calcium oxide 0.201 mol, totaling 11.256 g; magnesium oxide 0.0402 mol, totaling 1.608 g). After the deep purification of fluorine, phosphorus, and arsenic is completed, it enters the next process.

[0052] S5. Secondary filtration and washing: The slurry with deep purification of removing fluorine, phosphorus and arsenic obtained in step S4 is subjected to secondary filtration and washing to obtain a sodium tungstate molybdate solution with low fluorine, low phosphorus and low arsenic. First, filter the slurry with deep purification of removing fluorine, phosphorus and arsenic. After filtration is completed, secondary filtrate and secondary filter residue are obtained. Then, perform secondary washing. Wash with normal-temperature tap water until the soluble WO3 and soluble Mo in the residue are both less than 0.1%. In this embodiment, the added amount of washing water is 100 ml (washed in two times). After mixing the secondary filtrate, the secondary washing water and the normal-temperature washing water in step S3, the obtained sodium tungstate molybdate solution with low fluorine, low phosphorus and low arsenic can enter the tungsten smelting process. In this embodiment, the total volume of the obtained sodium tungstate molybdate solution with low fluorine, low phosphorus and low arsenic is 6280 ml. The sampling analysis results are F 0.8 mg / L, P 0.38 mg / L, As 0.15 mg / L, and the solidification rates of F, P and As are 99.99%, 99.98% and 99.99% respectively.

[0053] Example 2: This example is a method for efficient leaching of low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore with simultaneous solidification of fluorine, phosphorus and arsenic. The low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore used is the same as that in Example 1. As Figure 1 shown, the steps for efficient leaching of the low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore with simultaneous solidification of fluorine, phosphorus and arsenic by using the method of the present invention are as follows:

[0054] S1. Ball milling activation and crushing: Weigh 500 g of low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore, and perform ball milling activation and crushing in a wet environment. Control the mass ratio of the water added for ball milling to the mass of the added low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore to be 0.8:1, and the ball milling time to be 30 min. After ball milling is completed, the proportion of the mineral particle size of -325 mesh in the obtained mineral slurry is 99.38%.

[0055] S2. Simultaneous fixation of fluorine, phosphorus, and arsenic during hot-pressure leaching: Add the activated and crushed mineral slurry obtained in step S1 into a decomposition kettle (in this embodiment, the inner volume of the decomposition kettle is 5000 ml), and conduct hot-pressure leaching and simultaneous fixation of fluorine, phosphorus, and arsenic. Control the composition of the decomposing agent to be sodium carbonate - sodium hydroxide, and add a total molar amount that is 3.8 times the theoretical molar amount when using sodium hydroxide alone for decomposition (Calculation method: The total molar amount of WO3 and Mo in the mineral is 0.82 mol, where WO3 is 0.37 mol and Mo is 0.45 mol. If all are decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide is 1.64 mol. According to the condition, the designed total amount is 3.8 times the theory, so the total molar amount of sodium hydroxide is 6.232 mol, that is, the total molar amount of sodium carbonate - sodium hydroxide added is 6.232 mol), where the molar ratio of sodium hydroxide to sodium carbonate is 4:1 (then the amount of sodium hydroxide used is 4.9856 mol, totaling 199.42 g; the amount of sodium carbonate used is 1.2464 mol, totaling 132.07 g). Calcium oxide - magnesium sulfate - calcium chloride is used as a reagent for deep fixation of fluorine, phosphorus, and arsenic. The mass ratio of calcium oxide added to the original mass of the mineral is 1:15 (33.33 g of calcium oxide is added), the mass ratio of magnesium sulfate added to the original mass of the mineral is 1:40 (12.5 g of magnesium sulfate is added), and the mass ratio of calcium chloride added to the original mass of the mineral is 1:50 (10 g of calcium chloride is added). The decomposition temperature is 200 °C, and the decomposition time is 5 h. After the decomposition is completed, the decomposed hot slurry is obtained.

[0056] S3. Single-stage filtration and washing: After step S2 is completed, the decomposed hot slurry is filtered and washed. First, the decomposed hot slurry is filtered to obtain the first-stage filtrate and the first-stage filter residue. After filtration is completed, hot tap water (at a temperature of 45°C and a volume of 1000 ml) twice the original mass of the mineral is added for primary washing. The primary washing water and the first-stage filtrate are mixed to obtain a hot concentrated material, which is independently collected. After testing, the volume of the collected hot concentrated material is 1120 ml (F 4.3 mg / L, P 46.71 mg / L, As 42.60 mg / L). After the hot concentrated material is collected, two more washes are carried out. The first time, it is washed with hot tap water at a water temperature controlled at 45°C, and the amount of washing water used is 1 times the original mass of the mineral (500 ml). The hot washing water is collected separately and returned to step S1 for ball milling in the next cycle. Then, it is washed with normal-temperature tap water for the second time, and the amount of washing water used is 10 times the original mass of the mineral (5000 ml). The soluble WO3 and soluble Mo in the washed residue are controlled to be less than 0.1%. The normal-temperature washing water (after testing, its total volume is 4885 ml, F 0.71 mg / L, P 0.25 mg / L, As 0.15 mg / L) is collected and reserved for later use. The washed residue is dried and weighed to be 416.23 g. The sampling test results are F 0.76%, P 3.77%, As 5.86%, WO3 0.45%, Mo 0.28%. The synchronous solidification rates of fluorine, phosphorus, and arsenic are calculated to be 99.85%, 99.61%, and 99.75% respectively, and the leaching rates of WO3 and Mo are 97.82% and 97.31% respectively.

[0057] S4. Deep purification of fluorine, phosphorus, and arsenic from the hot concentrated material: Calcium oxide-magnesium oxide is added to the hot concentrated material obtained in step S3 for deep purification of fluorine, phosphorus, and arsenic. The stirring speed is controlled at 60 r / min, and the reaction time is 6 h. The total amount of calcium oxide-magnesium oxide added is 80 times the theoretical amount (calculation method: the total number of moles of fluorine, phosphorus, and arsenic in the hot concentrated material is 0.00258 mol, of which fluorine is 0.00025 mol, phosphorus is 0.00169 mol, and arsenic is 0.00064 mol. According to the dominant reaction mechanism, if all calcium oxide or magnesium oxide is used, the total amount of calcium oxide or magnesium oxide required is 0.3152 mol), and the molar ratio of calcium oxide to magnesium oxide is 5:1 (calcium oxide 0.2627 mol, totaling 14.71 g; magnesium oxide 0.0525 mol, totaling 2.1 g). After the deep purification of fluorine, phosphorus, and arsenic is completed, it enters the next process.

[0058] S5. Secondary filtration and washing: The deep-purified defluorinated, dephosphorized, and dearsenized slurry obtained in step S4 is subjected to secondary filtration and washing to obtain a sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic. First, filter the deep-purified defluorinated, dephosphorized, and dearsenized slurry. After filtration is completed, secondary filtrate and secondary filter residue are obtained. Then, perform secondary washing. Wash with tap water at room temperature until the soluble WO3 and soluble Mo in the residue are both less than 0.1%. In this embodiment, the amount of washing water added is 100 ml (washed in two batches). After mixing the secondary filtrate, secondary washing water, and the room-temperature washing water in step S3, the obtained sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic can enter the tungsten smelting process. In this embodiment, the total volume of the obtained sodium tungstate and sodium molybdate solution with low fluorine, low phosphorus, and low arsenic is 6065 ml. The sampling analysis results are F 0.65 mg / L, P 0.32 mg / L, As 0.18 mg / L, and the solidification rates of F, P, and As are 99.87%, 99.99%, and 99.99% respectively.

[0059] Example 3: This example is a method for efficient leaching and simultaneous solidification of fluorine, phosphorus, and arsenic from a low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore. The low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore used is provided by a mine in Hunan. The ore is first subjected to sample preparation and then quantitatively analyzed using a chemical method. The results are F 1.12%, P 4.45%, As 3.37%, Ca 16.44%, WO3 29.62%, Mo 2.67%. As Figure 1 shown, the steps for efficient leaching and simultaneous solidification of fluorine, phosphorus, and arsenic from the low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore using the method of the present invention are as follows:

[0060] S1. Ball milling activation and crushing: Weigh 500 g of the above-mentioned low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore and perform ball milling activation and crushing in a wet environment. Control the mass ratio of the water added during ball milling to the mass of the added low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore to be 1:1, and the ball milling time to be 25 min. After ball milling is completed, the proportion of the mineral particles with a particle size of -325 mesh in the mineral slurry is 98.61%.

[0061] S2. Simultaneous fixation of fluorine, phosphorus, and arsenic during hot - pressure leaching: Add the activated and crushed mineral slurry obtained in step S1 into a decomposition kettle (in this embodiment, the inner volume of the decomposition kettle is 5000 ml), and conduct hot - pressure leaching and simultaneous fixation of fluorine, phosphorus, and arsenic. The decomposition agent consists of sodium carbonate - sodium hydroxide, and the total amount added is 4.2 times the theoretical molar amount when using sodium hydroxide alone for decomposition (Calculation method: The total molar amount of WO3 and Mo in the mineral is 0.78 mol, where WO3 is 0.64 mol and Mo is 0.14 mol. If all are decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide is 1.56 mol. According to the condition, the designed total amount is 4.2 times the theory, so the total molar amount of sodium hydroxide is 6.552 mol, that is, the total molar amount of sodium carbonate - sodium hydroxide added is 6.552 mol). Among them, the molar ratio of sodium hydroxide to sodium carbonate is 5:1 (so the amount of sodium hydroxide used is 5.46 mol, totaling 218.40 g; the amount of sodium carbonate used is 1.092 mol, totaling 115.75 g). Calcium oxide - magnesium sulfate - calcium chloride is used as a deep - fixation reagent for fluorine, phosphorus, and arsenic. The mass ratio of calcium oxide added to the mineral mass is 1:15 (33.33 g of calcium oxide is added), the mass ratio of magnesium sulfate added to the mineral mass is 1:40 (12.5 g of magnesium sulfate is added), and the mass ratio of calcium chloride added to the mineral mass is 1:45 (11.11 g of calcium chloride is added). The decomposition temperature is 190 °C, and the decomposition time is 6 h. After decomposition is completed, a decomposed hot slurry is obtained.

[0062] S3. One-stage filtration and washing: After step S2 is completed, the decomposed hot pulp is filtered and washed. First, the decomposed hot pulp is filtered to obtain a first-stage filtrate and a first-stage filter residue. After filtration is completed, hot tap water (at a temperature of 50°C and a volume of 1000 ml) twice the original mass of the ore is added for primary washing. The primary washing water and the first-stage filtrate are mixed to obtain a hot concentrated material, which is collected independently. After testing, the volume of the collected hot concentrated material is 1285 ml (F 2.89 mg / L, P 40.12 mg / L, As 9.76 mg / L). After the hot concentrated material is collected, two more washes are carried out. The first time, it is washed with hot tap water with the water temperature controlled at 50°C and the amount of washing water being 1 times the original mass of the ore (500 ml). The hot washing water is collected separately and returned to step S1 in the next cycle for ball milling. Then, a secondary normal-temperature tap water wash is carried out with the amount of washing water being 12 times the original mass of the ore (6000 ml), controlling the soluble WO3 and soluble Mo in the washed residue to be less than 0.1%. The normal-temperature washing water (after testing, with a total volume of 5815 ml, F 0.64 mg / L, P 0.36 mg / L, As 0.20 mg / L) is collected for standby. The washed residue is dried and weighed to be 397.11 g. The sampling test results are F 1.41%, P 5.59%, As 4.24%, WO3 0.71%, Mo 0.22%. The synchronous solidification rates of fluorine, phosphorus, and arsenic are calculated to be 99.98%, 99.75%, and 99.81% respectively, and the leaching rates of WO3 and Mo are 98.10% and 93.46% respectively.

[0063] S4. Deep purification of fluorine, phosphorus, and arsenic from the hot concentrated material: Calcium oxide - magnesium oxide is added to the hot concentrated material obtained in step S3 for deep purification of fluorine, phosphorus, and arsenic. The stirring speed is controlled at 60 r / min, and the reaction time is 6 h. The total amount of calcium oxide - magnesium oxide added is 100 times the theoretical amount (calculation method: the total molar amount of fluorine, phosphorus, and arsenic in the hot concentrated material is 0.00203 mol / L, where fluorine is 0.0002 mol, phosphorus is 0.00166 mol, and arsenic is 0.00017 mol. According to the dominant reaction mechanism, if all calcium oxide or magnesium oxide is used, the total required amount of calcium oxide or magnesium oxide is 0.293 mol), and the molar ratio of calcium oxide to magnesium oxide is 5:1 (calcium oxide 0.2442 mol, totaling 13.68 g; magnesium oxide 0.0488 mol, totaling 1.952 g). After the deep purification of fluorine, phosphorus, and arsenic is completed, it enters the next process.

[0064] S5, Secondary Filtration and Washing: The deep-purified defluorinated, dephosphorized, and dearsenified slurry obtained in step S4 is subjected to secondary filtration and washing to obtain a sodium tungstate and sodium molybdate solution with low fluoride, low phosphorus, and low arsenic content. First, filter the deep-purified defluorinated, dephosphorized, and dearsenified slurry. After filtration is completed, secondary filtrate and secondary filter residue are obtained. Then, perform secondary washing. Wash with normal-temperature tap water until the soluble WO3 and soluble Mo in the residue are both less than 0.1%. In this embodiment, the addition amount of washing water is 100 ml (washed in two batches). After mixing the secondary filtrate, secondary washing water, and the normal-temperature washing water in step S3, the obtained sodium tungstate and sodium molybdate solution with low fluoride, low phosphorus, and low arsenic content can enter the tungsten smelting process. In this embodiment, the total volume of the obtained sodium tungstate and sodium molybdate solution with low fluoride, low phosphorus, and low arsenic content is 7200 ml. The sampling analysis results are F 0.39 mg / L, P 0.37 mg / L, As 0.11 mg / L, and the solidification rates of F, P, and As are 99.95%, 99.99%, and 99.99% respectively.

[0065] Comparative Example: The low-grade high-fluoride, high-phosphorus, and high-arsenic mixed tungsten ore used in this comparative example is the same as that in Example 3. The leaching amounts of various substances are detected by direct hot-pressure leaching. The process steps are as follows:

[0066] S1, Ball Milling Activation and Crushing: Weigh 500 g of low-grade high-fluoride, high-phosphorus, and high-arsenic mixed tungsten ore, and perform ball milling activation and crushing in a wet environment. Control the mass ratio of the water added for ball milling to the mass of the added low-grade high-fluoride, high-phosphorus, and high-arsenic mixed tungsten ore to be 1:1. The ball milling time is 25 min. After ball milling is completed, the proportion of the mineral particles with a particle size of -325 mesh in the mineral slurry is 98.72%.

[0067] S2, Direct Hot-Pressure Leaching: Add the activated and crushed mineral slurry obtained in step S1 into a decomposition kettle (the inner volume of the decomposition kettle used in this comparative example is 5000 ml), and perform hot-pressure leaching. The decomposing agent is sodium hydroxide, and the addition amount is 4.2 times the theoretical amount (Calculation method: The total molar amount of WO3 and Mo in the mineral is 0.78 mol, where WO3 is 0.64 mol and Mo is 0.14 mol. If all are decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide is 1.56 mol. According to the condition design, the total amount used is 4.2 times the theory, so the total molar amount of sodium hydroxide is 6.552 mol, totaling 262.08 g). The decomposition temperature is 190 °C, and the decomposition time is 6 h. After decomposition is completed, proceed to the next step;

[0068] S3. Filtration and washing: After step S2 is completed, the decomposed hot slurry is filtered and washed. First, the decomposed hot slurry is filtered to obtain a first-stage filtrate and a first-stage filter residue. After filtration is completed, hot tap water (at a temperature of 50 °C and a volume of 1000 ml) twice the original mass of the mineral is added for primary washing, and then secondary normal-temperature tap water washing is carried out. The amount of washing water used is 12 times the original mass of the mineral (6000 ml). The washed residue is dried and weighed to be 354.67 g. The sampling test results are F 1.52%, P 6.01%, As 4.22%, WO3 2.52%, Mo 0.71%. Then the dissolution rates of F, P, and As are 3.73%, 4.19%, and 11.17% respectively, and the leaching rates of WO3 and Mo are 93.97% and 81.14% respectively.

[0069] It can be seen from Example 1, Example 2, Example 3 and the comparative example that the method of the present invention can effectively improve the leaching rates of tungsten and molybdenum, and has a significant effect on the synchronous solidification of fluorine, phosphorus, and arsenic during leaching. After deep purification to remove fluorine, phosphorus, and arsenic, a sodium tungstate and molybdate solution with low fluorine, low phosphorus, and low arsenic can be obtained, effectively avoiding the common key problems of high difficulty in deep purification and high disposal cost caused by the diffusion and migration of fluorine, phosphorus, and arsenic pollutants during tungsten smelting.

[0070] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0071] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A method for efficient leaching of low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic, characterized in that, The steps are as follows: S1. Ball milling activation and crushing: Weigh a certain amount of low-grade tungsten ore with high fluorine, high phosphorus, and high arsenic, and conduct ball milling activation and crushing in a wet environment. After ball milling is completed, a mineral slurry is obtained and proceeds to the next step; S2. Hot-pressure leaching for simultaneous fluorine, phosphorus, and arsenic fixation: Add the mineral slurry, decomposing agent, and deep fluorine, phosphorus, and arsenic fixation reagent into the decomposition kettle for hot-pressure leaching and simultaneous fluorine, phosphorus, and arsenic fixation. The decomposing agent consists of sodium carbonate - sodium hydroxide, and the deep fluorine, phosphorus, and arsenic fixation reagent consists of calcium oxide - magnesium sulfate - calcium chloride. After decomposition is completed, a decomposed hot slurry is obtained and enters the next step; S3. First-stage filtration and washing: First, filter the decomposed hot slurry to obtain a first-stage filtrate and a first-stage filter residue. Add hot tap water to the first-stage filter residue for primary washing, and mix the primary washing water and the first-stage filtrate to obtain a hot concentrated material, which is independently collected and processed in the next step; Then, conduct two more washes. The first wash uses hot tap water, and the hot washing water is separately collected for use in the next step S1 for wet ball milling. The second wash uses normal-temperature tap water, and the normal-temperature washing water is collected for standby; S4. Deep purification of fluorine, phosphorus, and arsenic from the hot concentrated material: Add calcium oxide - magnesium oxide to the hot concentrated material and stir for deep purification of fluorine, phosphorus, and arsenic to obtain a slurry after deep purification of fluorine, phosphorus, and arsenic; S5. Second-stage filtration and washing: First, filter the slurry after deep purification of fluorine, phosphorus, and arsenic to obtain a second-stage filtrate and a second-stage filter residue. Then, wash the second-stage filter residue with normal-temperature tap water. Finally, mix the second-stage filtrate, the second-stage washing water, and the normal-temperature washing water in step S3 to obtain a sodium tungstate - molybdate solution with low fluorine, low phosphorus, and low arsenic.

2. The method for efficient leaching of low-grade high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore and simultaneous fixation of fluorine, phosphorus and arsenic according to claim 1, characterized in that, In step S1, the mass ratio of the water added during ball milling to the mass of the added low-grade tungsten ore with high fluorine, high phosphorus, and high arsenic is 0.8:1 to 1:1, and the ball milling time is 10 min to 30 min; after ball milling is completed, the proportion of the mineral particle size -325 mesh is ≥97%.

3. A method for efficient leaching of low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S2, the total molar amount of the decomposing agent added is 3.0 to 5.0 times the theoretical molar amount when decomposed with sodium hydroxide alone.

4. A method for efficiently leaching a low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore and simultaneously fixing fluorine, phosphorus, and arsenic according to claim 3, characterized in that, In step S2, the molar ratio of sodium hydroxide to sodium carbonate in the decomposing agent is 3:1 to 5:

1.

5. A method for efficient leaching of low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S2, the mass ratio of the calcium oxide added to the original mass of the mineral is 1:20 to 1:5, the mass ratio of the magnesium sulfate added to the original mass of the mineral is 1:40 to 1:20, and the mass ratio of the calcium chloride added to the original mass of the mineral is 1:50 to 1:

30.

6. A method for efficiently leaching a low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore and simultaneously fixing fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S2, the decomposition temperature is 150°C to 220°C, and the decomposition time is 3 h to 5 h.

7. A method for efficiently leaching a low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore and simultaneously fixing fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S3, the amount of hot tap water for primary washing is 1 to 2 times the mass of the original mineral, and the temperature is 40°C to 50°C; the water temperature for the first hot tap water wash is controlled at 40°C to 50°C, and the amount of washing water used is 1 to 2 times the mass of the original mineral; the amount of washing water used for the second normal-temperature tap water wash is 10 to 20 times the mass of the original mineral.

8. A method for efficient leaching of low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S4, the stirring speed is controlled at 60 r / min to 120 r / min, and the reaction time is 3 h to 6 h.

9. The method for efficient leaching of low-grade high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore with simultaneous fixation of fluorine, phosphorus and arsenic according to claim 1, characterized in that, In step S4, the total amount of calcium oxide - magnesium oxide added is 50 to 100 times the theoretical amount; the molar ratio of calcium oxide to magnesium oxide is 3:1 to 5:

1.

10. A method for efficiently leaching a low-grade high-fluorine, high-arsenic, and high-phosphorus mixed tungsten ore and simultaneously fixing fluorine, phosphorus, and arsenic according to claim 1, characterized in that, In step S5, when washing the secondary filter residue with normal-temperature tap water, wash until the soluble WO3 and soluble Mo in the residue are both less than 0.1%.

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