Method for efficiently leaching and synchronously fixing fluorine, phosphorus and arsenic from low-grade high-fluorine high-arsenic high-phosphorus mixed tungsten ore

Abstract

The invention relates to the field of green smelting of tungsten ores, in particular to a method for efficiently leaching and synchronously fixing fluorine, phosphorus and arsenic from low-grade high-fluorine high-arsenic high-phosphorus mixed tungsten ores. The method comprises the following steps: firstly, carrying out ball-milling activation and crushing on the low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore; then sodium hydroxide-sodium carbonate is used as a decomposing agent, calcium oxide-magnesium sulfate-calcium chloride is used as a deep fluorine, phosphorus and arsenic fixing reagent, tungsten and molybdenum are efficiently leached out under the hot pressing condition, and meanwhile synchronous dissolution of fluorine, phosphorus and arsenic is inhibited; carrying out first-stage filtration and washing; then calcium oxide-magnesium oxide is used for deep purification to remove fluorine, phosphorus and arsenic, and finally, solid-liquid separation is completed through two-stage filtering and washing, so that a low-fluorine, low-phosphorus and low-arsenic sodium tungstate molybdate solution is obtained. According to the method, the common key problems of high deep purification difficulty and high treatment cost caused by diffusion and migration in the whole process due to synchronous dissolution of fluorine, phosphorus and arsenic in the leaching process are solved 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. Since this type of mineral has a composite phase structure of scheelite phase (CaWO 4 ), wolframite phase (Fe(Mn)WO 4 ), and is rich in harmful elements such as F (0.5% - 2.0%), P (2% - 8%), As (3% - 10%), etc., and also contains valuable components such as WO 3 (15% - 30%), Mo (2% - 10%), and Ca (10% - 20%), etc., 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 WO 3 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 acids and alkalis 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, there are mainly three types of existing processes for treating such minerals: one is the high-fold alkali decomposition method, although this method can increase the leaching rate of tungsten and molybdenum to a certain extent, it requires 4 - 6 times the theoretical amount of alkali reagent, and the residual amount of WO 3 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, although it shows good decomposition effect on the scheelite phase, 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, this method 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 the co-dissolution of impurities, and generally have defects such as low metal recovery rate, difficult pollutant control, and high comprehensive costs. 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 for breaking through the green smelting technology barriers of low-grade tungsten ores with high fluorine, high phosphorus, and high arsenic. Summary of the Invention

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

[0006] By providing a method for efficiently leaching low-grade tungsten ores with high fluorine, high arsenic, and high phosphorus while synchronously fixing fluorine, phosphorus, and arsenic, the embodiments of the present application solve the problems in the existing technologies where fluorine, phosphorus, and arsenic are easily co-dissolved, leading to the diffusion and migration of fluorine, phosphorus, and arsenic pollutants throughout the process, making it difficult to achieve deep purification and resulting in high disposal costs. The tungsten and molybdenum are efficiently leached in the form of sodium tungstate and sodium molybdate, while the co-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 ores with high fluorine, high arsenic, and high phosphorus while synchronously fixing fluorine, phosphorus, and arsenic, and the steps are as follows: S1. Ball milling activation and crushing: Weigh a certain amount of low-grade tungsten ores with high fluorine, high phosphorus, and high arsenic, perform 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.

[0008] S2. Hot pressure leaching while synchronously fixing fluorine, phosphorus, and arsenic: Add the mineral slurry, decomposing agent, and deep fluorine, phosphorus, and arsenic fixing reagent obtained in step S1 into a decomposition kettle for hot pressure leaching and synchronous fluorine, phosphorus, and arsenic fixation. The decomposing agent consists of sodium carbonate - sodium hydroxide, and calcium oxide - magnesium sulfate - calcium chloride is used as the deep fluorine, phosphorus, and arsenic fixing reagent. After decomposition is completed, a decomposed hot slurry is obtained and proceeds to the next step.

[0009] S3. First-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 a first-stage filtrate and a first-stage filter residue. Hot tap water is added to the first-stage filter residue for primary washing, and the primary washing water and the first-stage filtrate are mixed to obtain a hot concentrated material, which is independently collected and processed in the next step. After the hot concentrated material is collected, two more washes are performed. The first wash uses hot tap water, and the hot washing water is separately collected and returned to step S1 for wet environment ball milling in the next cycle. Then, a secondary normal temperature tap water wash is performed, and the normal temperature washing water is collected for standby.

[0010] S4. Deep purification of hot concentrated material to remove fluorine, phosphorus, and arsenic: Add calcium oxide - magnesium oxide to the hot concentrated material obtained in step S3 and stir to conduct deep purification to remove fluorine, phosphorus, and arsenic.

[0011] S5. Secondary filtration and washing: Conduct secondary filtration and washing on the slurry after deep purification to remove fluorine, phosphorus, and arsenic obtained in step S4 to obtain a sodium tungstate - molybdate solution with low fluorine, low phosphorus, and low arsenic. First, filter the slurry after deep purification to remove fluorine, phosphorus, and arsenic. After filtration is completed, obtain secondary filtrate and secondary filter residue. Then wash the secondary filter residue 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 - molybdate solution with low fluorine, low phosphorus, and low arsenic is obtained.

[0012] Sample and analyze the concentrations of fluorine, phosphorus, and arsenic in the sodium tungstate - molybdate solution with low fluorine, low phosphorus, and low arsenic, and the solidification rates of fluorine, phosphorus, and arsenic can be calculated.

[0013] 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 high - arsenic mixed tungsten ore added is 0.8:1 to 1:1, and the ball - milling time is 10 min to 30 min.

[0014] 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 mineral surface is activated and the fine tungsten mineral particles wrapped are dissociated.

[0015] As some embodiments of the present application, 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.

[0016] As some embodiments of the present application, in step S2, the molar ratio of sodium hydroxide to sodium carbonate in the decomposing agent is 3:1 to 5:1.

[0017] As some embodiments of the present application, 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 addition amount of calcium chloride to the original mass of the mineral is 1:50 to 1:30.

[0018] 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.

[0019] As some embodiments of the present application, 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.

[0020] As some embodiments of the present application, in step S3, the water temperature of 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 original mass of the mineral.

[0021] As some embodiments of the present application, in step S3, the amount of washing water for the secondary normal temperature tap water washing is 10 to 20 times the original mass of the mineral.

[0022] As some embodiments of the present application, 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.

[0023] As 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.

[0024] As some embodiments of the present application, in step S4, the molar ratio of calcium oxide to magnesium oxide is 3:1 to 5:1.

[0025] As some embodiments of the present application, in step S5, when washing the secondary-stage filter residue with normal temperature tap water, wash until the soluble WO 3 and soluble Mo in the residue are both less than 0.1%.

[0026] The process mechanism of the technical solution provided in the embodiments of the present application is as follows: By ball milling and activating and crushing the low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore, it lays a foundation for the next efficient decomposition. Then, hot pressure leaching is used to simultaneously fix fluorine, phosphorus, and arsenic. Using sodium hydroxide - sodium carbonate as the decomposing agent can not only ensure that the scheelite phase (CaWO 4 ) in the low-grade high-fluorine high-phosphorus high-arsenic mixed tungsten ore can be fully leached: CaWO 4(S) +Na 2 CO 3(aq) →Na 2 WO 4(aq) +CaCO 3(S) At the same time, it can efficiently decompose the wolframite phase (Fe(Mn)WO 4 ), and the simultaneously added calcium oxide - magnesium sulfate - calcium chloride is used as a deep fluorine, phosphorus, and arsenic fixation reagent, so that the dissolved F is solidified in the decomposition residue in the form of stable calcium fluorophosphate (Ca 5 (PO 4 ) 3 F): 5CaO (S) +5H 2 O - (aq) +F - (aq) +3PO 43- (aq) →Ca 5 (PO 4 ) 3 F (S) +10 OH - (aq) The dissolved P is solidified in the decomposition slag in the form of stable calcium phosphate (Ca 3 (PO 4 ) 2 ) and magnesium phosphate (Mg 3 (PO 4 ) 2 ): 3MgO (S) +3H 2 O (aq) +2PO 4 3- (aq) →Mg 3 (PO 4 ) 2(S) +6 OH - (aq) 3CaO (S) +3H 2 O+2PO 4 3- (aq) →Ca 3 (PO 4 ) 2(S) +6 OH - (aq) The dissolved As enters the slag in the form of poorly soluble calcium basic arsenate [Ca 3 (AsO 4 ) 2 ·Ca(OH) 2 : 4CaO(S)+4H 2 O+2AsO 4 3- (aq) →Ca 3 (AsO 4 ) 2 ·Ca(OH) 2(S) +6 OH - (aq) After filtration and washing in one stage, the obtained hot concentrated material enters the next processing step. The hot washing water is returned to the wet environmental ball milling step for recycling, and 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, the hot concentrated material is deeply purified to remove fluorine, phosphorus, and arsenic. 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 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 basic arsenate are all smaller than those of calcium tungstate and calcium molybdate, thus achieving deep purification of fluorine, phosphorus, and arsenic while inhibiting the secondary coprecipitation of tungsten and molybdenum to ensure the recovery rate of target metals). Two-stage filtration and washing are carried out to separate the residues of deep purification to remove fluorine, phosphorus, and arsenic from the sodium tungstate 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, making the deep purification difficult and the disposal cost high.

[0027] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. Synchronously and efficiently solidify fluorine, phosphorus, and arsenic, and inhibit the diffusion of pollutants at the source: By using a combination of calcium oxide - magnesium sulfate - calcium chloride reagents in the hot pressure leaching stage, the dissolved fluorine, phosphorus, and arsenic are respectively formed 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.

[0028] 2. Significantly improve the leaching rates of tungsten and molybdenum and achieve resource utilization: Using a sodium hydroxide - sodium carbonate composite decomposing agent and an optimized ball milling activation process to synchronously and efficiently decompose scheelite phase and wolframite phase, realizing the efficient leaching of tungsten and molybdenum, and effectively improving the utilization rate of low-grade tungsten ore resources.

[0029] 3. Low treatment cost and high applicability: By recycling the hot washing water to the ball milling step for reuse, and using the normal temperature washing water for batching with the purified concentrated material, the consumption of tap water and chemical reagents is reduced; combined with segmented filtration and washing and deep purification processes, the complexity of traditional multi-stage purification processes 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 ore qualities is guaranteed to meet the requirements of industrial production. Description of the Drawings

[0030] 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 the description of 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.

[0031] Figure 1 Schematic process flow diagram of an embodiment of the present invention. Specific embodiments

[0032] By providing a method for efficient leaching of low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic, the embodiments of the present application solve the problems of the prior art being restricted by the dual constraints of mineral phase differences and co-dissolution of impurities, and generally having defects such as low metal recovery rate, difficult pollutant control, and high comprehensive cost. The general idea is as follows: First, the low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore is ball-milled to complete the activation and crushing of mineral particles, and then hot-pressure leaching is carried out with simultaneous fixation of fluorine, phosphorus, and arsenic. Using sodium hydroxide-sodium carbonate as the decomposing agent and calcium oxide-magnesium sulfate-calcium chloride as the deep fluorine, phosphorus, and arsenic fixation reagent, under hot-pressure conditions, tungsten and molybdenum are efficiently leached in the form of sodium tungstate and sodium molybdate, while simultaneously inhibiting the co-dissolution of fluorine, phosphorus, and arsenic. This not only realizes the resource utilization of valuable metals tungsten and molybdenum, but also deeply solidifies fluorine, phosphorus, and arsenic. Then, through single-stage filtration and washing, the solid-liquid separation of the thick material and the slag is completed. The hot thick material is deeply purified to remove fluorine, phosphorus, and arsenic using calcium oxide-magnesium oxide, and then through two-stage filtration and washing, the solid-liquid separation is completed to obtain a low-fluorine, low-phosphorus, and low-arsenic sodium tungstate and sodium molybdate solution.

[0033] To better understand the above technical solutions, the following will detail the above technical solutions in specific embodiments.

[0034] Example 1: This example is a method for efficient leaching of low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic. The low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore used is provided by a certain mine in Hunan. The ore is first subjected to sample preparation and then quantitatively analyzed using a chemical method. The results are F 0.64%, P 3.15%, As 4.89%, Ca 11.79%, WO 3 17.15%, Mo 8.65%. As Figure 1 shown, the steps for efficient leaching of the low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore with simultaneous fixation of fluorine, phosphorus, and arsenic using the method of the present invention are as follows: 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 is completed, the proportion of mineral particles with a size of -325 mesh in the mineral slurry is 98.15%.

[0035] S2. Hot-pressure leaching for simultaneous fixation of fluorine, phosphorus and arsenic: 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), and carry out 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 amount of addition is 4.0 times the theoretical molar amount when using sodium hydroxide alone for decomposition (calculation method: the total molar amount of WO 3 and Mo in the mineral is 0.82 mol, among which WO 3 is 0.37 mol and Mo is 0.45 mol. If all are decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide used is 1.64 mol. According to the conditions, 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), among which 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 the added calcium oxide to the original mass of the mineral is 1:20 (25 g of calcium oxide is added), the mass ratio of the added magnesium sulfate to the original mass of the mineral is 1:40 (12.5 g of magnesium sulfate is added), the mass ratio of the added calcium chloride 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, a decomposed hot slurry is obtained.

[0036] 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 40°C and a volume of 1000 ml) twice the original mass of the mineral is added for primary washing. The primary wash 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 1265 ml (F 5.18 mg / L, P 42.68 mg / L, As 36.78 mg / L). After the hot concentrated material is collected, two more washes are carried out. The first time is washed with hot tap water, the water temperature is controlled at 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 step S1 for ball milling in the next time. Then, a secondary normal-temperature tap water wash is carried out, and the amount of washing water used is 10 times the original mass of the mineral (5000 ml). It is controlled that the soluble WO 3 and soluble Mo in the washed residue are both 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%, WO 3 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 WO 3 , Mo are 96.76% and 97.07% respectively.

[0037] 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 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). Among them, 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.

[0038] S5, Secondary filtration and washing: The deep purification 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 purification defluorinated, dephosphorized, and dearsenized 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 WO 3 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 times). 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 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 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.

[0039] Example 2: This example is a method for efficient leaching and simultaneous fixation 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 the same as that in Example 1. As Figure 1 shown, the steps for efficient leaching and simultaneous fixation 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: 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%.

[0040] S2, Hot pressure leaching and simultaneous fixation of fluorine, phosphorus, and arsenic: 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 perform 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 added molar amount is 3.8 times the theoretical molar amount when decomposing with sodium hydroxide alone (calculation method: the total molar amount of WO 3 and Mo in the mineral is 0.82 mol, where WO 3It is 0.37 mol, and Mo is 0.45 mol. If all is decomposed with sodium hydroxide, the theoretical consumption of sodium hydroxide is 1.64 mol. According to the conditions, the total designed consumption is 3.8 times the theoretical value, 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. Among them, the molar ratio of sodium hydroxide to sodium carbonate is 4:1 (so 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), 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, the decomposition time is 5 h. After decomposition is completed, a decomposed hot pulp is obtained.

[0041] 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 a first - stage filtrate and a first - stage filter residue. After filtration is completed, hot tap water (temperature is 45 °C, volume is 1000 ml) with a mass 2 times that of the original 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 detection, 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, it is washed twice more. The first time is washed with hot tap water, the water temperature is controlled at 45 °C, and the amount of washing water used is 1 times the mass of the original mineral (500 ml). The hot washing water is collected separately and returned to the next step S1 for ball - milling use. Then, it is washed with normal - temperature tap water for the second time, and the amount of washing water used is 10 times the mass of the original mineral (5000 ml). Control the soluble WO 3 and soluble Mo in the washing residue to be less than 0.1%. The normal - temperature washing water (after detection, its total volume is 4885 ml, F 0.71 mg / L, P 0.25 mg / L, As 0.15 mg / L) is collected for standby. The washing residue is dried and weighed to be 416.23 g. The sampling detection results are F 0.76%, P 3.77%, As 5.86%, WO 3 0.45%, Mo 0.28%. Calculate the synchronous solidification rates of fluorine, phosphorus, and arsenic to be 99.85%, 99.61%, 99.75% respectively, and the leaching rates of WO 3 and Mo to be 97.82% and 97.31% respectively.

[0042] S4. Deep purification of hot concentrated material to remove fluorine, phosphorus and arsenic: Add calcium oxide - magnesium oxide to the hot concentrated material obtained in step S3 for deep purification to remove fluorine, phosphorus and arsenic. The stirring speed is controlled at 60 r / min, the reaction time is 6 h, and 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, including 0.00025 mol of fluorine, 0.00169 mol of phosphorus, and 0.00064 mol of arsenic. 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). The molar ratio of calcium oxide to magnesium oxide is 5:1 (0.2627 mol of calcium oxide, totaling 14.71 g; 0.0525 mol of magnesium oxide, totaling 2.1 g). After the deep purification to remove fluorine, phosphorus and arsenic is completed, it enters the next process.

[0043] S5. Secondary filtration and washing: Perform secondary filtration and washing on the slurry obtained in step S4 after deep purification to remove fluorine, phosphorus and arsenic to obtain a sodium tungstate - molybdate solution with low fluorine, low phosphorus and low arsenic. First, filter the slurry after deep purification to remove fluorine, phosphorus and arsenic. After filtration is completed, obtain secondary filtrate and secondary filter residue, and then perform secondary washing. Wash with normal - temperature tap water until the soluble WO 3 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 times). After mixing the secondary filtrate, 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 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.

[0044] Example 3: This example is a method for efficient leaching of low - grade high - fluorine high - phosphorus high - arsenic mixed tungsten ore with simultaneous fixation of fluorine, phosphorus and arsenic. 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 by chemical method. The results are F 1.12%, P 4.45%, As 3.37%, Ca 16.44%, WO 3 29.62%, Mo 2.67%. As Figure 1 shown, the steps for efficient leaching of this low - grade high - fluorine high - phosphorus high - arsenic mixed tungsten ore with simultaneous fixation of fluorine, phosphorus and arsenic using the method of the present invention are as follows: 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 25 min. After ball milling is completed, the proportion of mineral particles with a size of -325 mesh in the mineral slurry is 98.61%.

[0045] S2. Hot pressure leaching for simultaneous fluorine, phosphorus and arsenic fixation: 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 carry out hot pressure leaching and simultaneous fluorine, phosphorus and arsenic fixation. The composition of the decomposing agent is 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 WO 3 and Mo in the mineral is 0.78 mol, where WO 3 is 0.64 mol and Mo is 0.14 mol. If all is decomposed with sodium hydroxide, the theoretical amount of sodium hydroxide used 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 (then 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 fluorine, phosphorus and arsenic fixation reagent. 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 addition amount of calcium chloride 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.

[0046] 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 the first-stage filtrate and the first-stage filter residue. After filtration is completed, hot tap water (temperature 50°C, volume 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 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 is washed with hot tap water, the water temperature is controlled at 50°C, and the amount of washing water used is 1 time the original mass of the mineral (500 ml). The hot washing water is separately collected and returned to step S1 for ball milling in the next time. Then, a secondary normal temperature tap water wash is carried out, and the amount of washing water used is 12 times the original mass of the mineral (6000 ml), controlling the soluble WO 3 and soluble Mo in the washed residue to be less than 0.1%. The normal temperature washing water (after testing, its total volume is 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%, WO 3 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 WO 3 and Mo are 98.10% and 93.46% respectively.

[0047] 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, of which 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 amount of calcium oxide or magnesium oxide required is 0.293 mol), where 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.

[0048] 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 and sodium 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 WO 3 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 times). 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 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 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.

[0049] Comparative Example: The low-grade tungsten ore with high fluorine, high phosphorus and high arsenic 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: S1, Ball Milling Activation and Crushing: Weigh 500 g of low-grade tungsten ore with high fluorine, high phosphorus and high arsenic, 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 tungsten ore with high fluorine, high phosphorus and high arsenic to be 1:1, and the ball milling time is 25 min. After ball milling is completed, the proportion of the mineral particle size -325 mesh in the mineral slurry is 98.72%.

[0050] 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 WO 3 and Mo in the mineral is 0.78 mol, among which WO 3 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, totaling 262.08 g), the decomposition temperature is 190 °C, and the decomposition time is 6 h. After decomposition is completed, enter the next step; 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%, WO 3 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 WO 3 , Mo are 93.97% and 81.14% respectively.

[0051] 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 difficult deep purification and high disposal costs caused by the diffusion and migration of fluorine, phosphorus, and arsenic pollutants during tungsten smelting.

[0052] 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 to include the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0053] 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 also intends to include these changes and modifications.

Claims

1. A method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore, characterized in that: Here are the steps: S1. Ball milling activation and crushing: Weigh a certain amount of low-grade high-fluorine, high-phosphorus, and high-arsenic mixed tungsten ore, and perform ball milling activation and crushing in a wet environment. After the ball milling is completed, a mineral slurry is obtained and the next step is entered; S2. Hot-pressing leaching and simultaneous fluorine, phosphorus and arsenic fixation: adding mineral slurry, decomposer and deep fluorine, phosphorus and arsenic fixation reagent into a decomposition kettle for hot-pressing leaching and simultaneous fluorine, phosphorus and arsenic fixation; the decomposer is composed of sodium carbonate-sodium hydroxide, and the deep fluorine, phosphorus and arsenic fixation reagent is composed of calcium oxide-magnesium sulfate-calcium chloride. After decomposition is completed, decomposed hot ore slurry is obtained and the next step is entered; S3, one-stage filtration and washing: first, the decomposed hot slurry is filtered to obtain a filtrate and a filter residue, hot tap water is added to the filter residue for primary washing, the primary washing water and the filtrate are mixed to obtain a hot concentrated material, which is collected independently and processed in the next step; Then, two more washings are performed. The first washing is performed with hot tap water, and the hot washing water is collected separately for the next step S1 of wet environment ball milling. The second washing is performed with normal temperature tap water, and the normal temperature washing water is collected for later use. S4. Deep purification of hot concentrated material for removal of fluorine, phosphorus and arsenic: Add calcium oxide-magnesium oxide to the hot concentrated material and stir to perform deep purification for removal of fluorine, phosphorus and arsenic, and obtain a deep purification slurry for removal of fluorine, phosphorus and arsenic; S5, second-stage filtration and washing: first, filter the deep-purification fluorine, phosphorus and arsenic removal slurry to obtain the second-stage filtrate and the second-stage filter residue, then wash the second-stage filter residue with normal temperature tap water, and finally mix the second-stage filtrate, the second-stage washing water and the normal temperature washing water in step S3 to obtain a low-fluorine, low-phosphorus, low-arsenic sodium tungstate molybdate solution.

2. The method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore according to claim 1 is characterized in that: In step S1, the mass ratio of water added to the ball milling to the mass ratio of 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; after the ball milling is completed, the mineral particle size -325 mesh accounts for ≥97%.

3. The method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore according to claim 1 is 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 sodium hydroxide is used alone for decomposition.

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

1.

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

30.

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

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

8. The method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore according to claim 1 is characterized in that: 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.

9. The method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore according to claim 1 is 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. The method for efficiently leaching and simultaneously fixing fluorine, phosphorus and arsenic from low-grade, high-fluorine, high-arsenic and high-phosphorus mixed tungsten ore according to claim 1 is characterized in that: In step S5, the second-stage filter residue is washed with tap water at room temperature until the soluble WO3 and soluble Mo in the residue are less than 0.1%.

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