A method for extracting vanadium-molybdenum from vanadium-bearing shale ore

Abstract

This invention relates to the field of vanadium extraction technology from shale coal, and more particularly to a method for extracting vanadium and molybdenum from shale coal vanadium ore. The method involves decarbonizing and roasting a ground shale coal vanadium ore sample, followed by sodium roasting; acid leaching in a sulfuric acid solution, separating the leaching solution and leaching residue; using a trihexyl(tetrafluoro)phosphonic chloride organic solution of appropriate concentration range as an extractant for the leaching solution, utilizing the significant differences in the extraction behavior of molybdenum and vanadium at different pH values ​​to achieve stepwise selective extraction; optimizing the sulfuric acid solution concentration to efficiently strip molybdenum and vanadium from the organic phase; extracting the remaining molybdenum from the leaching residue with ammonia leaching; and performing molybdenum precipitation, vanadium precipitation reactions, and calcination to obtain vanadium and molybdenum concentrate products. This method not only achieves efficient synergistic recovery of vanadium and molybdenum, but also yields vanadium and molybdenum concentrate products with extremely high purity, meeting the needs of high-end applications and possessing significant industrial application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of extracting vanadium from stone coal, and particularly relates to a method for extracting vanadium and molybdenum from stone coal vanadium ore. BACKGROUND

[0002] At present, vanadium resources in China mainly depend on vanadium slag extraction, and the production capacity faces a bottleneck. As a characteristic and advantageous resource in China, efficient development and utilization of stone coal vanadium ore is expected to break through the production capacity limit of vanadium products. However, stone coal vanadium ore is complex in composition and contains quartz, muscovite, pyrite, calcite, kaolinite and carbonaceous minerals, etc., resulting in that, in addition to the target element vanadium, the leaching solution also contains a large amount of interference ions such as calcium, iron, aluminum, silicon and molybdenum. Molybdenum among the interference ions has high economic value. If vanadium can be efficiently extracted while molybdenum is also efficiently extracted, the comprehensive utilization rate of resources and economic benefits can be significantly improved.

[0003] The existing vanadium extraction method generally consists of processes such as roasting, leaching, ion exchange or extraction, ammonium metavanadate precipitation, and calcination to prepare refined vanadium, such as salt-free roasting-acid leaching-solvent extraction method, fluidized roasting-acid leaching-ion exchange method, acid leaching-intermediate salt method, etc. Among them, the key problems faced in the purification and separation link are:

[0004] The selectivity of various ions is poor, and the selectivity of conventional organic extractants or ion exchange resins to various ions in the complex leaching solution is generally not strong. Impurity ions such as calcium, iron, aluminum and silicon are easily co-extracted or co-adsorbed with vanadium and molybdenum, which makes it difficult to remove impurities in the subsequent process and seriously affects the purity of the final vanadium product.

[0005] The separation efficiency of vanadium and molybdenum is low, and vanadium and molybdenum have similar chemical properties in solution (such as both being easy to form polyacid anions), which makes it difficult for conventional separation methods to achieve efficient and selective separation of vanadium and molybdenum. Incomplete separation of vanadium and molybdenum not only causes the loss of high-value molybdenum resources, but also interferes with the deep purification of vanadium, forming a mutually restraining bottleneck.

[0006] The molybdenum recovery rate is low. After acid leaching, part of the molybdenum element enters the acid leaching solution, and part of the molybdenum element remains in the acid leaching residue. The current conventional method only extracts molybdenum in the acid leaching residue, resulting in incomplete recovery of molybdenum and low recovery rate. SUMMARY

[0007] The purpose of the present application is to provide a method for extracting vanadium and molybdenum from stone coal vanadium ore, which can extract both vanadium and molybdenum from stone coal vanadium ore, and the purity of the products is high.

[0008] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0009] A method for extracting vanadium and molybdenum from stone coal vanadium ore, comprising the following steps:

[0010] (1) grinding the stone coal vanadium ore to a particle size of less than or equal to 0.08 mm; first decarburization roasting; then adding sodium carbonate for sodium roasting, the sodium carbonate addition amount being 6-8 wt% of the raw material after decarburization roasting, to obtain calcine;

[0011] (2) immersing the calcine into a 0.5-0.8 M sulfuric acid solution, stirring and leaching to obtain an acid leaching solution and an acid leaching residue;

[0012] (3) dissolving trihexyl(tetradecyl)phosphonium chloride in an aromatic hydrocarbon diluent to obtain a trihexyl(tetradecyl)phosphonium chloride organic solution;

[0013] adjusting the pH of the acid leaching solution to 0.3-0.5, adding the trihexyl(tetradecyl)phosphonium chloride organic solution, and extracting to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase;

[0014] (4) stripping the molybdenum-containing organic phase with a 3-5 M sulfuric acid solution to obtain a molybdenum-containing acid solution;

[0015] (5) after water washing the acid leaching residue, immersing it in ammonia water, heating in a water bath, and ammonia leaching molybdenum to obtain an ammonia leaching solution;

[0016] (6) mixing the molybdenum-containing acid solution and the ammonia leaching solution, adjusting the pH of the mixed solution to 1.5-2, then adding ammonium sulfate, stirring for molybdenum precipitation, standing, filtering, washing, drying, calcining, to obtain MoO3 fine powder;

[0017] (7) adjusting the pH of the vanadium-containing aqueous phase to 1.5-2.0, adding the trihexyl(tetradecyl)phosphonium chloride organic solution, and extracting to obtain a vanadium-containing organic phase;

[0018] (8) stripping the vanadium-containing organic phase with a 0.3-0.5 M sulfuric acid solution to obtain a vanadium-containing solution;

[0019] (9) adjusting the pH of the vanadium-containing solution to 9-10, adding ammonium sulfate, stirring for vanadium precipitation, standing, filtering, washing, drying, calcining, to obtain V2O5 fine powder.

[0020] Preferably, in the step (1), the decarburization roasting temperature is 750-800℃, and the roasting time is 0.5-1 h; the sodium roasting temperature is 700-750℃, and the roasting time is 2-3 h.

[0021] Preferably, in the step (2), the mass ratio of the sulfuric acid solution to the calcine is 2:1-3:1; the leaching temperature is 70-90℃, the leaching time is 1.5-2 h, and the stirring speed is 400-800 r / min.

[0022] Preferably, in the step (3), the concentration of trihexyl(tetradecyl)phosphonium chloride in the organic solution is 0.05-0.15 M; the volume ratio of the acid leaching solution to the trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1-3:1; the extraction temperature is 30-50 DEG C; and the extraction time is 20-60 min.

[0023] Preferably, in the step (4), the volume ratio of the sulfuric acid solution to the molybdenum-containing organic phase is 2:1-3:1; the stripping temperature is 30-50 DEG C; and the stripping time is 20-60 min.

[0024] Preferably, in the step (5), the mass ratio of the ammonia water to the acid leaching residue is 8:1-10:1; the concentration of the ammonia water is 15-20 wt%; the ammonia leaching temperature is 70-90 DEG C; and the ammonia leaching time is 2-3 h.

[0025] Preferably, in the step (6), the molybdenum precipitation reaction temperature is 40-60 DEG C; the molybdenum precipitation reaction stirring time is 1-2 h; the standing time is 1-2 h; the calcination temperature is 300-500 DEG C; and the calcination time is 2-3 h.

[0026] Preferably, in the step (7), the concentration of trihexyl(tetradecyl)phosphonium chloride in the organic solution is 0.05-0.15 M; the volume ratio of the vanadium-containing aqueous phase to the trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1-3:1; the extraction temperature is 30-50 DEG C; and the extraction time is 20-60 min.

[0027] Preferably, in the step (8), the volume ratio of the sulfuric acid solution to the vanadium-containing organic phase is 2:1-3:1; the stripping temperature is 30-50 DEG C; and the stripping time is 20-60 min.

[0028] Preferably, in the step (9), the vanadium precipitation temperature is 40-50 DEG C; the vanadium precipitation reaction stirring time is 1-2 h; the standing time is 1-2 h; the calcination temperature is 300-400 DEG C; and the calcination time is 2-3 h.

[0029] The present application has the following advantages:

[0030] 1. The present application firstly grinds the stone coal vanadium ore, then removes carbon and roasts, which can effectively remove carbon, destroy mica lattice, oxidize low-grade vanadium and molybdenum, and promote the dissociation and conversion of vanadium and molybdenum; then roasts by adding sodium carbonate, the CO2 released by the decomposition of sodium carbonate makes the mineral structure loose, and the purpose of the two-stage roasting is to improve the leaching rate of vanadium and molybdenum in the leaching process through synergistic effect.

[0031] 2、The application adopts trihexyl (tetradecyl) phosphine chloride organic solution as an extractant, improves the selectivity of vanadium and molybdenum extraction separation by regulating the concentration of trihexyl (tetradecyl) phosphine chloride in the organic solution and the pH of the aqueous phase, reduces the content of impurity ions in the extraction phase, and realizes efficient separation of vanadium and molybdenum, and obtains high-purity vanadium-containing organic phase and molybdenum-containing organic phase; when the concentration of trihexyl (tetradecyl) phosphine chloride in the organic solution is 0.05-0.15M and the pH of the acid leaching solution is 0.3-0.5, the selectivity of the extractant to molybdenum is high; when the concentration of trihexyl (tetradecyl) phosphine chloride in the organic solution is 0.05-0.15M and the pH of the vanadium-containing aqueous phase is 1.5-2.0, the selectivity of the extractant to vanadium is high; by regulating the pH of the aqueous phase, efficient separation of vanadium and molybdenum is realized by using the above characteristics of the extractant; it should be noted that when the pH of the aqueous phase is 1.5-2.0, although the selectivity of the extractant to vanadium is high, a small amount of molybdenum will also be brought into the extraction process, which will affect the utilization rate of vanadium and the purity of the product, therefore, attention should be paid to the extraction sequence, molybdenum is extracted first, and then vanadium is extracted, so as to prevent molybdenum from entering the vanadium extraction phase and affecting the separation effect of vanadium and molybdenum.

[0032] 3、When a traditional acid leaching process is used for acid leaching of stone coal vanadium ore, molybdenum in the acid leaching residue is mainly extracted, about 20% of the molybdenum enters the acid leaching solution, and due to the high content of impurity ions in the acid leaching solution, this part of molybdenum is difficult to recover, the application uses trihexyl (tetradecyl) phosphine chloride organic solution as an extractant to extract the acid leaching solution, and high-purity molybdenum-containing organic phase can be obtained, and then sulfuric acid solution is used to strip the molybdenum-containing organic phase to obtain high-purity molybdenum-containing acid solution, and since the content of impurity ions in the molybdenum-containing acid solution is extremely low, the molybdenum in the acid leaching solution can also be recovered, compared with the prior art, the recovery rate of molybdenum is significantly improved. DETAILED DESCRIPTION

[0033] The specific implementation of the application is further illustrated below in combination with examples, but the implementation and protection of the application are not limited thereto. The examples use a certain stone coal vanadium ore sample from Qinghai Dagan Gou, and the mineral composition of the sample is shown in Table 1.

[0034] Example 1

[0035] (1) For the sample with V2O5 grade of 0.95wt% and Mo grade of 0.35wt%, the sample is ground to a particle size of 0.08mm, and first decarburization roasting is performed, the roasting temperature is 800℃, and the roasting time is 45min. Then sodium roasting is performed by adding sodium carbonate, the sodium carbonate addition amount is 6wt% of the original material after decarburization roasting, the roasting temperature is 750℃, the roasting time is 2.5h, and the roasted sand is obtained after natural cooling.

[0036] (2) The calcine is subjected to sulfuric acid solution leaching, the leaching temperature is 70°C, the leaching time is 2h, the sulfuric acid solution concentration is 0.5M, the mass ratio of sulfuric acid solution to calcine is 2:1, the stirring speed is 400r / min, and the acid leaching liquid and acid leaching residue are obtained through solid-liquid separation. The concentrations of two-phase metals are analyzed and calculated by inductively coupled plasma atomic emission spectrometry (ICP-AES), the vanadium leaching rate is 92.31%, and the molybdenum leaching rate is 29.71%.

[0037] (3) Trihexyl(tetradecyl)phosphonium chloride is dissolved in ShellSol A150 aromatic hydrocarbon diluent (from Shell Company) to prepare a trihexyl(tetradecyl)phosphonium chloride organic solution, and the concentration of trihexyl(tetradecyl)phosphonium chloride is 0.1M.

[0038] The pH value is monitored by using a Hanna portable pH meter, and the pH of the acid leaching liquid is adjusted to 0.5 by sulfuric acid. The acid leaching liquid is extracted in a hexagonal glass reactor at a temperature of 45°C for 20min, and the volume ratio of acid leaching liquid to trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1. After extraction, filtration separation is performed by using a 0.45μm Supor membrane filter to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase. The molybdenum extraction rate reaches 97.5%, and a small amount of vanadium is contained, and the vanadium extraction rate is 0.25%.

[0039] (4) The molybdenum-containing organic phase is stripped in a hexagonal glass reactor by using a 5M H2SO4 solution, the volume ratio of sulfuric acid solution to molybdenum-containing organic phase is 2:1, the stripping temperature is 45°C, the stripping time is 20min, and a molybdenum-containing acid solution is obtained. The molybdenum stripping rate reaches 96.7%.

[0040] (5) After the acid leaching residue is washed with water twice, ammonia leaching is performed by using ammonia water / acid leaching residue with a mass ratio of 8:1, the concentration of ammonia water is 20%, the water bath heating temperature is 70°C, the ammonia leaching time is 2h, and the ammonia leaching liquid is obtained by filtration, and the molybdenum leaching rate is 95.2%.

[0041] (6) After the molybdenum-containing acid solution and the ammonia leaching liquid are mixed, the pH is adjusted to 2 by using sulfuric acid, ammonium sulfate is added, and molybdenum precipitation is performed. The molybdenum precipitation temperature is 60°C, the stirring reaction time is 2h, and the stirring reaction is placed for 1h, and the ammonium molybdate precipitate is obtained by filtration and washing. After the precipitate is dried, calcination is performed at a temperature of 500°C in a muffle furnace for 3h to obtain MoO3 fine powder products, and the MoO3 content in the molybdenum fine powder is 99.01%.

[0042] (7) The pH of the vanadium-containing aqueous phase in step (3) is adjusted to 2.0, and the trihexyl(tetradecyl)phosphonium chloride organic solution prepared in step (3) is added, the volume ratio of vanadium-containing aqueous phase to trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1, and extraction is performed in a hexagonal glass reactor at a temperature of 45°C for 20min to obtain a vanadium-containing organic phase. The vanadium extraction rate reaches 97.8%, and the molybdenum extraction rate is 0.16%.

[0043] (8) The vanadium-containing organic phase was stripped with 0.5 M H2SO4 solution in a hexagonal glass reactor, the volume ratio of sulfuric acid solution to vanadium-containing organic phase was 2:1, the stripping temperature was 45°C, and the stripping time was 20 min, to obtain a vanadium-containing solution. The vanadium back-extraction rate reached 97.8%.

[0044] (9) The vanadium-containing solution was adjusted to pH=9 by sodium hydroxide, and ammonium sulfate was added to carry out the vanadium precipitation reaction. The temperature was 45°C, stirring for 2 h and standing for 1 h, then filtering and washing to obtain ammonium metavanadate. After drying, the ammonium metavanadate was calcined in a muffle furnace at a temperature of 350°C for 3 h to obtain V2O5 fine powder product. The V2O5 content in the vanadium fine powder was 98.77%. Example 2

[0045] (1) For the sample with V2O5 grade of 0.9wt% and Mo grade of 0.50wt%, the sample was ground to a particle size of 0.075 mm, and pre-decarbonization roasting was carried out. The roasting temperature was 800°C, and the roasting time was 30 min. Sodium carbonate was added at a dosage of 6wt% for sodium roasting, the roasting temperature was 750°C, the roasting time was 2.5h, and the roasted sand was obtained after natural cooling.

[0046] (2) The roasted sand was subjected to acid leaching. The leaching temperature was 70°C, the leaching time was 2h, the sulfuric acid solution concentration was 0.6M, the mass ratio of sulfuric acid solution to roasted sand was 3:1, and the stirring speed was 600r / min. After solid-liquid separation, an acid leaching solution and an acid leaching residue were obtained. The concentrations of the two-phase metals were analyzed and calculated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The vanadium leaching rate was 93.52%, and the molybdenum leaching rate was 25.83%.

[0047] (3) Trihexyl(tetradecyl)phosphonium chloride was dissolved in ShellSol A150 aromatic hydrocarbon diluent (from Shell Company) to prepare a trihexyl(tetradecyl)phosphonium chloride organic solution. The concentration of trihexyl(tetradecyl)phosphonium chloride was 0.1M.

[0048] The pH value was monitored using a Hanna portable pH meter. The pH of the acid leaching solution was adjusted to 0.5 by sulfuric acid. The acid leaching solution and the trihexyl(tetradecyl)phosphonium chloride organic solution were mixed in a hexagonal glass reactor at a volume ratio of 3:1 and extracted at 45°C for 60 min. After extraction, the aqueous solution was filtered with a 0.45μm Supor membrane filter to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase. The molybdenum extraction rate reached 98.03%, and the vanadium extraction rate was 0.20%.

[0049] (4) The molybdenum-containing organic phase was stripped with 5M H2SO4 solution in a hexagonal glass reactor, the volume ratio of sulfuric acid solution to molybdenum-containing organic phase was 3:1, the stripping temperature was 45°C, and the stripping time was 60 min, to obtain a molybdenum-containing acid solution. The molybdenum back-extraction rate reached 96.24%.

[0050] (5) After twice water washing of the acid leaching residue, ammonia leaching was carried out with ammonia water and acid leaching residue in a mass ratio of 8:1, ammonia water concentration of 20%, water bath heating temperature of 90°C, and ammonia leaching time of 2h, to obtain an ammonia leaching solution, and the molybdenum leaching rate was 97.26%.

[0051] (6) After mixing the molybdenum-containing acid solution and the ammonia leaching solution, the pH was adjusted to 2, and ammonium sulfate was added to carry out molybdenum precipitation. The molybdenum precipitation temperature was 60°C, the stirring reaction time was 2h, and the standing time was 1h, to obtain ammonium molybdate precipitate after filtration and washing. After drying the precipitate, calcination was carried out in a muffle furnace at a temperature of 450°C for 3h to obtain MoO3 fine powder product, and the MoO3 content in the molybdenum fine powder was 99.21%.

[0052] (7) The pH of the vanadium-containing aqueous phase in step (3) was adjusted to 1.8, and the trihexyl(tetradecyl) phosphine chloride organic solution prepared in step (3) was added, and the volume ratio of the vanadium-containing aqueous phase to the trihexyl(tetradecyl) phosphine chloride organic solution was 2:1. Extraction was carried out in a hexagonal glass reactor at a temperature of 45°C for 60min to obtain a vanadium-containing organic phase. The vanadium extraction rate reached 97.43%, and the molybdenum extraction rate was 0.09%.

[0053] (8) The vanadium-containing organic phase was stripped in a hexagonal glass reactor with 0.5M H2SO4 solution, the volume ratio of the sulfuric acid solution to the vanadium-containing organic phase was 3:1, the stripping temperature was 45°C, and the stripping time was 20min to obtain a vanadium-containing solution. The vanadium stripping rate reached 97.39%.

[0054] (9) The vanadium-containing solution was adjusted to pH=9 by adding sodium hydroxide, and ammonium sulfate was added to carry out vanadium precipitation. The temperature was 45°C, the stirring time was 2h, and the standing time was 1h, to obtain ammonium metavanadate after filtration and washing. After drying, calcination was carried out in a muffle furnace at a temperature of 350°C for 2.5h to obtain V2O5 fine powder product, and the V2O5 content in the vanadium fine powder was 99.04%. Example 3

[0055] (1) For a sample with a V2O5 grade of 1.1wt% and a Mo grade of 0.65wt%, the sample was ground to a particle size of 0.075mm, and a pre-decarbonization roasting was carried out at a roasting temperature of 750°C for 60min. Sodium roasting was carried out by adding 7wt% sodium carbonate at a roasting temperature of 700°C for 3h, and the roasted sand was obtained after natural cooling.

[0056] (2) The roasted sand was subjected to acid leaching at a leaching temperature of 90°C for 1.5h, a sulfuric acid solution concentration of 0.8M, a sulfuric acid solution to roasted sand mass ratio of 2:1, and a stirring speed of 800r / min, to obtain an acid leaching solution and an acid leaching residue. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to analyze and calculate the metal concentrations in the two phases, and the vanadium leaching rate was 92.95% and the molybdenum leaching rate was 24.79%.

[0057] (3) Trihexyl (tetradecyl) phosphonium chloride was dissolved in ShellSol A150 aromatic hydrocarbon diluent to prepare a trihexyl (tetradecyl) phosphonium chloride organic solution, and the concentration of the trihexyl (tetradecyl) phosphonium chloride was 0.05M.

[0058] The pH value was monitored by using a Hanna portable pH meter, the pH of the acid leaching solution was adjusted to 0.3 by sulfuric acid, and the extraction was carried out at a temperature of 50°C for 30 min, and the volume ratio of the acid leaching solution to the trihexyl (tetradecyl) phosphonium chloride organic solution was 2:1. After extraction, the aqueous solution was filtered by using a 0.45 μm Supor membrane filter to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase. The molybdenum extraction rate reached 98.74%, and a small amount of vanadium was contained, and the vanadium extraction rate was 0.13%.

[0059] (4) The molybdenum-containing organic phase was stripped in a hexagonal glass reactor by using a 3M H2SO4 solution, the volume ratio of the sulfuric acid solution to the molybdenum-containing organic phase was 2:1, the stripping temperature was 30°C, and the stripping time was 60 min to obtain a molybdenum-containing acid solution. The molybdenum back-extraction rate reached 97.83%, and the vanadium content was substantially zero.

[0060] (5) After the acid leaching residue was washed with water twice, ammonia leaching was carried out by using ammonia water and the acid leaching residue in a mass ratio of 8:1, the concentration of the ammonia water was 15%, the water bath heating temperature was 70°C, and the ammonia leaching time was 3 h, and the ammonia leaching solution was obtained by filtration, and the molybdenum leaching rate was 97.45%.

[0061] (6) After the molybdenum-containing acid solution and the ammonia leaching solution were mixed, the pH was adjusted to 1.5, and ammonium sulfate was added to carry out a molybdenum precipitation reaction. The molybdenum precipitation temperature was 50°C, the stirring reaction time was 1 h, and the standing time was 2 h, and the ammonium molybdate precipitate was obtained by filtration and washing. After the precipitate was dried, calcination was carried out in a muffle furnace at a temperature of 500°C for 2 h to obtain MoO3 fine powder products, and the MoO3 content in the molybdenum fine powder was 99.53%.

[0062] (7) The pH of the vanadium-containing aqueous phase in step (3) was adjusted to 1.5, and the trihexyl (tetradecyl) phosphonium chloride organic solution prepared in step (3) was added, the volume ratio of the vanadium-containing aqueous phase to the trihexyl (tetradecyl) phosphonium chloride organic solution was 3:1, and the extraction was carried out in a hexagonal glass reactor at a temperature of 50°C for 30 min to obtain a vanadium-containing organic phase. The vanadium extraction rate reached 98.04%, and the molybdenum extraction rate was 0.12%.

[0063] (8) The vanadium-containing organic phase was stripped in a hexagonal glass reactor by using a 0.3M H2SO4 solution, the volume ratio of the sulfuric acid solution to the vanadium-containing organic phase was 2:1, the stripping temperature was 30°C, and the stripping time was 60 min to obtain a vanadium-containing solution. The vanadium back-extraction rate reached 98.39%.

[0064] (9) The vanadium-containing solution was adjusted to pH=10 by sodium hydroxide, and ammonium sulfate was added to carry out the vanadium precipitation reaction. The temperature was 40°C, and after stirring for 1 h, it was placed for 2 h. Ammonium metavanadate was obtained by filtration and washing, and after drying, it was calcined in a muffle furnace at a temperature of 400°C for 2 h to obtain V2O5 fine powder product. The V2O5 content in the vanadium fine powder was 98.63%. Example 4

[0065] (1) For the sample with V2O5 grade of 1.2wt% and Mo grade of 0.80wt%, the sample was ground to a particle size of 0.07mm, and a decarburization roasting was carried out in advance. The roasting temperature was 750°C, and the roasting time was 50min. 7wt% of sodium carbonate was added for sodium roasting, the roasting temperature was 700°C, the roasting time was 2.5h, and the calcine was obtained by natural cooling.

[0066] (2) The calcine was subjected to acid leaching. The leaching temperature was 90°C, the leaching time was 2h, the sulfuric acid solution concentration was 0.8M, the mass ratio of sulfuric acid solution to calcine was 3:1, and the stirring speed was 600r / min. The acid leaching liquid and acid leaching residue were obtained by solid-liquid separation. The concentrations of two-phase metals were analyzed and calculated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The vanadium leaching rate was 93.64%, and the molybdenum leaching rate was 26.47%.

[0067] (3) Trihexyl(tetradecyl)phosphonium chloride was dissolved in ShellSol A150 aromatic hydrocarbon diluent (from Shell Company) to prepare an organic solution. The concentration of trihexyl(tetradecyl)phosphonium chloride was 0.15M.

[0068] The pH value was monitored using a Hanna portable pH meter. The pH of the acid leaching liquid was adjusted to 0.4 by sulfuric acid. The extraction was carried out in a hexagonal glass reactor at a temperature of 30°C for 40min. The volume ratio of acid leaching liquid to trihexyl(tetradecyl)phosphonium chloride organic solution was 3:1. After extraction, the aqueous solution was filtered with a 0.45μm Supor membrane filter to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase. The molybdenum extraction rate reached 98.59%, and a small amount of vanadium was contained, with a vanadium extraction rate of 0.11%.

[0069] (4) The molybdenum-containing organic phase was stripped in a hexagonal glass reactor with 3M H2SO4 solution. The volume ratio of sulfuric acid solution to molybdenum-containing organic phase was 3:1, the stripping temperature was 30°C, and the stripping time was 40min. A molybdenum-containing acid solution was obtained. The molybdenum stripping rate reached 97.62%.

[0070] (5) After the acid leaching residue was washed twice with water, ammonia leaching was carried out with an ammonia water and acid leaching residue mass ratio of 10:1. The ammonia water concentration was 15%, the water bath heating temperature was 80°C, and the ammonia leaching time was 3h. The ammonia leaching liquid was obtained by filtration, and the molybdenum leaching rate was 98.04%.

[0071] (6) The molybdenum-containing acid solution and the ammonia leaching solution are mixed, and then the pH is adjusted to 1.5, and ammonium sulfate is added to carry out the molybdenum precipitation reaction. The molybdenum precipitation temperature is 40°C, and after stirring for 1 h, it is allowed to stand for 2 h, and then the ammonium molybdate precipitate is obtained by filtration and washing. After drying the precipitate, calcination is carried out in a muffle furnace at a temperature of 350°C for 3 h to obtain MoO3 fine powder product, and the MoO3 content in the molybdenum fine powder is 99.43%.

[0072] (7) The pH of the vanadium-containing aqueous phase in step (3) is adjusted to 2.0, and the trihexyl(tetradecyl)phosphonium chloride organic solution prepared in step (3) is added, and the volume ratio of the vanadium-containing aqueous phase to the trihexyl(tetradecyl)phosphonium chloride organic solution is 3:1. Extraction is carried out in a hexagonal glass reactor at a temperature of 30°C for 40 min to obtain a vanadium-containing organic phase. The vanadium extraction rate reaches 98.52%, and the molybdenum extraction rate is 0.14%.

[0073] (8) The vanadium-containing organic phase is stripped with a 0.4M H2SO4 solution in a hexagonal glass reactor, and the volume ratio of the sulfuric acid solution to the vanadium-containing organic phase is 2:1. The stripping temperature is 30°C, and the stripping time is 40 min to obtain a vanadium-containing solution. The vanadium stripping rate reaches 98.62%.

[0074] (9) The vanadium-containing solution is adjusted to pH=9.5 by sodium hydroxide, and ammonium sulfate is added to carry out the vanadium precipitation reaction. The temperature is 50°C, and after stirring for 1 h, it is allowed to stand for 2 h, and then ammonium metavanadate is obtained by filtration and washing. After drying, calcination is carried out in a muffle furnace at a temperature of 400°C for 3 h to obtain V2O5 fine powder product, and the V2O5 content in the vanadium fine powder is 98.58%. Example 5

[0075] (1) For a sample with a V2O5 grade of 0.85wt% and a Mo grade of 0.94wt%, the sample is ground to a particle size of 0.08mm, and pre-decarbonization roasting is carried out. The roasting temperature is 780°C, and the roasting time is 40 min. Sodium roasting is carried out by adding 8wt% sodium carbonate, and the roasting temperature is 750°C, and the roasting time is 3h. The roasted sand is obtained by natural cooling.

[0076] (2) The roasted sand is subjected to acid leaching. The leaching temperature is 80°C, the leaching time is 2h, the sulfuric acid solution concentration is 0.8M, the mass ratio of the sulfuric acid solution to the roasted sand is 3:1, and the stirring speed is 400r / min. After solid-liquid separation, an acid leaching solution and an acid leaching residue are obtained. The metal concentrations in the two phases are analyzed and calculated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The vanadium leaching rate is 91.49%, and the molybdenum leaching rate is 27.58%.

[0077] (3) Trihexyl(tetradecyl)phosphonium chloride is dissolved in ShellSol A150 aromatic hydrocarbon diluent (from Shell Company) to prepare an organic solution, and the concentration of trihexyl(tetradecyl)phosphonium chloride is 0.1M.

[0078] The pH value was monitored using a Hanna portable pH meter, and the pH of the acid leaching solution was adjusted to 0.5 by sulfuric acid. The acid leaching solution and the trihexyl(tetradecyl)phosphonium chloride organic solution were extracted in a hexagonal glass reactor at a volume ratio of 2:1 for 30 min at 40°C. After extraction, the aqueous solution was filtered using a 0.45 μm Supor membrane filter to obtain an organic phase containing molybdenum and an aqueous phase containing vanadium. The molybdenum extraction rate reached 98.04%, and the aqueous phase contained a small amount of vanadium, with a vanadium extraction rate of 0.05%.

[0079] (4) The organic phase containing molybdenum was stripped in a hexagonal glass reactor using a 5M H2SO4 solution, the volume ratio of the sulfuric acid solution to the organic phase containing molybdenum was 2:1, the stripping temperature was 40°C, and the stripping time was 50 min to obtain a molybdenum-containing acid solution. The molybdenum back-extraction rate reached 96.94%.

[0080] (5) After the acid leaching residue was washed twice with water, ammonia leaching was performed using ammonia water and the acid leaching residue at a mass ratio of 9:1, the ammonia water concentration was 18%, the water bath heating temperature was 90°C, and the ammonia leaching time was 3 h. The ammonia leaching solution was filtered to obtain a molybdenum leaching rate of 96.21%.

[0081] (6) After the molybdenum-containing acid solution and the ammonia leaching solution were mixed, the pH was adjusted to 1.5, and ammonium sulfate was added to perform a molybdenum precipitation reaction. The molybdenum precipitation temperature was 60°C, the stirring reaction time was 2 h, and the standing time was 1 h. The molybdenum ammonium precipitate was obtained after filtration and washing. After the precipitate was dried and calcined in a muffle furnace at a temperature of 450°C for 2.5 h, a MoO3 fine powder product was obtained, and the MoO3 content in the molybdenum fine powder was 99.03%.

[0082] (7) The pH of the vanadium-containing aqueous phase in step (3) was adjusted to 1.5, and the trihexyl(tetradecyl)phosphonium chloride organic solution prepared in step (3) was added. The volume ratio of the vanadium-containing aqueous phase to the trihexyl(tetradecyl)phosphonium chloride organic solution was 3:1, the extraction temperature was 40°C, and the extraction time was 30 min in a hexagonal glass reactor to obtain a vanadium-containing organic phase. The vanadium extraction rate reached 97.94%, and the molybdenum extraction rate was 0.08%.

[0083] (8) The vanadium-containing organic phase was stripped in a hexagonal glass reactor using a 0.3M H2SO4 solution, the volume ratio of the sulfuric acid solution to the vanadium-containing organic phase was 3:1, the stripping temperature was 40°C, and the stripping time was 50 min to obtain a vanadium-containing solution. The vanadium back-extraction rate reached 97.95%, and the molybdenum content was negligible.

[0084] (9) The vanadium-containing solution was adjusted to pH=10 by adding sodium hydroxide, and ammonium sulfate was added to perform a vanadium precipitation reaction. The temperature was 45°C, the stirring time was 1 h, and the standing time was 2 h. The ammonium metavanadate was obtained after filtration and washing, and was dried and calcined in a muffle furnace at a temperature of 400°C for 2.5 h to obtain a V2O5 fine powder product. The V2O5 content in the vanadium fine powder was 98.83%. Comparative Example 1

[0085] The sodium roasting was directly carried out at 750℃ for 3.25h without decarburization roasting in the present comparative example, and other processes were consistent with those of example 1. The vanadium leaching rate was 86.36% and the molybdenum leaching rate was 20.17% after sulfuric acid solution acid leaching in step (2). Comparative example 2

[0086] The concentration of trihexyl (tetradecyl) phosphine chloride was 0.2M in step (3) of the present comparative example, and other processes were consistent with those of example 1. The molybdenum extraction rate was 83.53%, the vanadium extraction rate was 2.45%, the iron extraction rate was 6.2%, and the potassium extraction rate was 0.5% in step (3). Comparative example 3

[0087] The pH of the acid leaching solution was 0.7 in step (3) of the present comparative example, and other processes were consistent with those of example 1. The molybdenum extraction rate was 82.83% in step (3). Comparative example 4

[0088] The pH of the vanadium-containing aqueous phase was 1.2 in step (7) of the present comparative example, and other processes were consistent with those of example 1. The vanadium extraction rate was 72.73% in step (7). Comparative example 5

[0089] The concentration of trihexyl (tetradecyl) phosphine chloride was 0.2M in step (7) of the present comparative example, and other processes were consistent with those of example 1. The vanadium extraction rate was 84.63%, the molybdenum extraction rate was 13.4%, the iron extraction rate was 10.35%, and the potassium extraction rate was 3.5% in step (7). Comparative example 6

[0090] The vanadium-molybdenum extraction order was changed in the present comparative example compared with example 1, i.e. vanadium was extracted first and then molybdenum was extracted, and other process conditions were the same. The steps were simplified as follows:

[0091] 1) The stone coal vanadium ore was ground to a particle size of ≤0.08mm, then decarburization roasting was carried out, then sodium roasting was carried out by adding sodium carbonate, the amount of sodium carbonate added was 6-8wt% of the decarburization roasted raw material, and the roasted sand was obtained by natural cooling;

[0092] 2) The roasted sand was immersed in a sulfuric acid solution and stirred to leach, obtaining an acid leaching solution and an acid leaching residue;

[0093] 3) Trihexyl (tetradecyl) phosphine chloride was dissolved in an aromatic hydrocarbon diluent to obtain a trihexyl (tetradecyl) phosphine chloride organic solution; the pH of the acid leaching solution was adjusted to 1.5-2.0, and the trihexyl (tetradecyl) phosphine chloride organic solution was added to obtain a vanadium-containing organic phase and a molybdenum-containing aqueous phase;

[0094] 4) The pH of the molybdenum-containing aqueous phase was adjusted to 0.3-0.5, and the trihexyl (tetradecyl) phosphine chloride organic solution was added to obtain a molybdenum-containing organic phase;

[0095] In step 3), the vanadium extraction rate reaches 90.5%, and part of the molybdenum is extracted, with a molybdenum extraction rate of 7.5%; in step 4), the molybdenum extraction rate reaches 97.22%.

[0096] The data obtained from the examples and comparative examples are shown in Tables 2 and 3.

[0097]

[0098]

[0099] As can be seen from the analysis of the test results of Examples 1-5 in Table 2, within the specified operating parameter range, the vanadium and molybdenum extraction rates of each step are high, the separation effect is good, and the product purity is high.

[0100] As can be seen from the analysis of the test results of the comparative examples in Table 3, the following can be seen:

[0101] Comparative Example 1 fully demonstrates the advantages of decarburization roasting. This process can effectively remove carbon, destroy the mica lattice, oxidize low-grade vanadium and molybdenum, promote the dissociation and conversion of vanadium and molybdenum, and improve the leaching rate of vanadium and molybdenum in the leaching process. Among them, the carbon content in stone coal is relatively high, and the leaching particle size is relatively fine and widely distributed in mineral particles, which affects the distribution of heat during roasting and consumes additional acid during leaching, seriously affecting the effect of vanadium extraction. Therefore, it is necessary to perform decarburization and oxidation roasting on stone coal. After acid leaching of the sulfuric acid solution after decarburization and oxidation roasting, the vanadium and molybdenum leaching rates are greatly improved. The vanadium leaching rate of Examples 1-5 is 91.49%-93.64%, and the molybdenum leaching rate is 24.79%-29.71%. According to the calculation method, the difference between the values of the examples and the values of the comparative examples is divided by the values of the comparative examples to calculate the improvement score of the leaching rate. The vanadium leaching rate of Example 1 after acid leaching of the sulfuric acid solution is improved by 6.89% compared with Comparative Example 1. The improvement of each leaching rate described below is also calculated according to this method.

[0102] Comparative Example 2 fully demonstrates that a high concentration of trihexyl(tetradecyl)phosphonium chloride organic solution is not conducive to the extraction of molybdenum. When the concentration of the organic solution is increased, the metal loading capacity is improved, and a certain amount of iron, potassium and other impurity elements are extracted, which relatively reduces the selectivity of molybdenum. The molybdenum extraction rate of Example 1 is improved by 16.72% compared with Comparative Example 2.

[0103] Comparative Example 3 fully demonstrates that when the pH of the acid leaching solution is higher than 0.5, the molybdenum extraction rate decreases. The molybdenum extraction rate of Example 1 is improved by 17.71% compared with Comparative Example 3.

[0104] Comparative Example 4 fully demonstrates that in the process of extracting vanadium with trihexyl(tetradecyl)phosphonium chloride organic solution, a too low pH of the vanadium-containing aqueous phase is not conducive to improving the vanadium extraction rate. The vanadium extraction rate of Example 1 is improved by 34.47% compared with Comparative Example 4.

[0105] The comparative example 5 fully illustrates that, in the process of extracting vanadium by using trihexyl (tetradecyl) phosphonium chloride organic solution, the concentration of trihexyl (tetradecyl) phosphonium chloride is too high to be unfavorable for the extraction of vanadium; after the concentration of the organic solution is increased, the metal loading capacity is improved, and other impurity elements such as iron and potassium are extracted, and relatively, the selectivity for vanadium is reduced; the vanadium extraction rate of the example 1 is increased by 15.56% compared with the comparative example 5;

[0106] The comparative example 6 changes the extraction order of vanadium and molybdenum in the system compared with the example 1, that is, vanadium is extracted first and then molybdenum is extracted, and other process conditions are the same; it is verified that the extraction of vanadium from the acid leaching solution is simplified, the vanadium extraction rate is 90.5%, and part of molybdenum is contained, the molybdenum extraction rate is 7.5%, and the extraction effect is not ideal.

Claims

1. A method for extracting vanadium and molybdenum from stone coal vanadium ore, characterized in that, The method comprises the following steps: (1) grinding stone coal vanadium ore to a particle size of less than or equal to 0.08 mm; first decarburization roasting; then adding sodium carbonate for sodium roasting, the sodium carbonate addition amount being 6-8 wt% of the raw material after decarburization roasting, to obtain roasted sand; (2) immersing the roasted sand in a 0.5-0.8 M sulfuric acid solution, and stirring to leach, to obtain an acid leaching solution and an acid leaching residue; (3) dissolving trihexyl(tetradecyl)phosphonium chloride in an aromatic hydrocarbon diluent to obtain a trihexyl(tetradecyl)phosphonium chloride organic solution; adjusting the pH of the acid leaching solution to 0.3-0.5, adding the trihexyl(tetradecyl)phosphonium chloride organic solution, and extracting to obtain a molybdenum-containing organic phase and a vanadium-containing aqueous phase; the concentration of trihexyl(tetradecyl)phosphonium chloride in the organic solution is 0.05-0.15 M; (4) stripping the molybdenum-containing organic phase with a 3-5 M sulfuric acid solution to obtain a molybdenum-containing acid solution; (5) after washing the acid leaching residue, immersing it in ammonia water, and heating in a water bath to perform ammonia leaching of molybdenum, to obtain an ammonia leaching solution; (6) mixing the molybdenum-containing acid solution and the ammonia leaching solution, adjusting the pH of the mixed solution to 1.5-2, and then adding ammonium sulfate to stir to perform molybdenum precipitation, standing, filtering, washing, drying, and calcining, to obtain MoO3 fine powder; (7) adjusting the pH of the vanadium-containing aqueous phase to 1.5-2.0, adding the trihexyl(tetradecyl)phosphonium chloride organic solution, and extracting to obtain a vanadium-containing organic phase; the concentration of trihexyl(tetradecyl)phosphonium chloride in the organic solution is 0.05-0.15 M; (8) stripping the vanadium-containing organic phase with a 0.3-0.5 M sulfuric acid solution to obtain a vanadium-containing solution; (9) adjusting the pH of the vanadium-containing solution to 9-10, adding ammonium sulfate to stir to perform vanadium precipitation, standing, filtering, washing, drying, and calcining, to obtain V2O5 fine powder.

2. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (1), the decarburization roasting temperature is 750-800 DEG C, and the roasting time is 0.5-1 h; the sodium roasting temperature is 700-750 DEG C, and the roasting time is 2-3 h.

3. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (2), the mass ratio of the sulfuric acid solution to the roasted sand is 2:1-3:1; the leaching temperature is 70-90 DEG C, the leaching time is 1.5-2 h, and the stirring speed is 400-800 r / min.

4. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (3), the volume ratio of the acid leaching solution to the trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1-3:1, the extraction temperature is 30-50 DEG C, and the extraction time is 20-60 min.

5. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (4), the volume ratio of the sulfuric acid solution to the molybdenum-containing organic phase is 2:1-3:1; the stripping temperature is 30-50 DEG C, and the stripping time is 20-60 min.

6. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (5), the mass ratio of the ammonia water to the acid leaching residue is 8:1-10:1, the ammonia water concentration is 15-20 wt%, the ammonia leaching temperature is 70-90 DEG C, and the ammonia leaching time is 2-3 h.

7. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (6), the molybdenum precipitation reaction temperature is 40-60 DEG C, the molybdenum precipitation reaction stirring time is 1-2 h, the standing time is 1-2 h, the calcining temperature is 300-500 DEG C, and the calcining time is 2-3 h.

8. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (7), the volume ratio of the vanadium-containing aqueous phase to the trihexyl(tetradecyl)phosphonium chloride organic solution is 2:1-3:1, the extraction temperature is 30-50 DEG C, and the extraction time is 20-60 min.

9. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (8), the volume ratio of sulfuric acid solution to vanadium-containing organic phase is 2:1-3:1; the stripping temperature is 30-50℃, and the stripping time is 20-60 min.

10. The method for extracting vanadium and molybdenum from stone coal vanadium ore according to claim 1, characterized in that, In the step (9), the vanadium precipitation temperature is 40-50℃, the vanadium precipitation reaction stirring time is 1-2 h, and the standing time is 1-2 h; the calcination temperature is 300-400℃, and the calcination time is 2-3 h.

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