Method for preparing vanadium, chromium, aluminum and silicon products through gradient separation of vanadium shale

Abstract

The invention relates to a method for preparing vanadium, chromium, aluminum and silicon products through gradient separation of vanadium shale. According to the technical scheme, silicon in the vanadium shale alkaline leaching solution is removed through a sulfuric acid precipitation method, and a desilicication solution and a siliceous precursor I are obtained; washing the siliceous precursor I with sulfuric acid, washing with water and calcining to obtain white carbon black; carrying out vanadium-chromium co-extraction on the desilicication liquid by adopting an amine extraction agent to obtain a vanadium-chromium organic phase; carrying out vanadium-aluminum extraction separation on the washing liquid by adopting an amine extraction agent to obtain a vanadium-rich organic phase and an aluminum-containing raffinate; the vanadium-rich organic phase and the vanadium-chromium organic phase are mixed, vanadium-chromium separation is achieved through step-by-step reverse extraction, and vanadium-rich liquid and chromium-rich liquid are obtained; adjusting the pH value of the aluminum-containing raffinate to precipitate aluminum hydroxide, and calcining to obtain aluminum oxide; carrying out ammonium salt vanadium precipitation on the vanadium-rich liquid to obtain ammonium polyvanadate, and calcining to obtain vanadium pentoxide; and reducing the chromium-rich liquid, adjusting the pH value, precipitating chromium hydroxide, and calcining to obtain chromium sesquioxide. The method is high in leaching rate, small in slag amount, high in product purity and high in recovery rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of vanadium extraction from shale. Specifically, it relates to a method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. Background Art

[0002] Alkali leaching of vanadium shale has the characteristics of good selectivity, few types of impurity ions, high alkalinity, high concentration of impurity ions in the solution, and less slag. However, the leaching solution belongs to a high-alkali multi-impurity system, and the pH of the leaching solution is usually higher than 14, containing high concentrations of Na + , K + , Si, Al, Cr and other impurity ions; under alkaline conditions, silicon exists in the form of SiO3 2- , and it is easy to form silicon-aluminum colloid with Al 3+ , adsorb vanadate ions, resulting in the loss of vanadium; then there is the problem of multi-metal separation. Chromium (Cr) and vanadium (V) have similar chemical properties, and it is difficult to achieve selective separation by traditional precipitation methods; while aluminum (Al) exists in the form of AlO2 - , and it will compete with vanadium for extraction sites when using the extraction method for separation, resulting in poor separation effect. The above problems seriously restrict the recovery of vanadium and the purity of vanadium products. Therefore, developing green and efficient separation technologies and realizing the separation and resource utilization of vanadium and impurity ions have become one of the hot topics of concern for scientific and technological personnel.

[0003] For the patented technology of "a method for extracting vanadium from vanadium shale by segmented microwave roasting-stepwise alkali leaching" (CN 115725863A), by utilizing the efficient selective heating characteristics of microwave on vanadium shale, the lattice destruction of vanadium-containing minerals in the microwave crystal-breaking roasting process is strengthened, and thus the efficiency of microwave crystal-breaking roasting is improved. However, the vanadium leaching rate of this process is relatively low, only 78.94%.

[0004] Long Sisi et al. (Long Sisi, Feng Qiming, Zhang Guofan, Ou Leming, Lu Yiping. Recovery of silicon and vanadium from the leaching solution of the V-Si-CO3 2- -H2O system and regeneration of the leaching agent [J]. Journal of Central South University (Science and Technology), 2014, 45: 663-670) proposed a process of stone coal oxidative roasting-alkali leaching-neutralization for impurity removal-solvent extraction-ammonium salt precipitation of vanadium-calcination to produce refined vanadium. This process directly precipitates silicon from the high-concentration silicon-containing leaching solution with CO2 as the pH adjuster, and uses the causticization process to increase the alkalinity of the remaining solution after vanadium extraction, so as to regenerate the leaching agent. However, the purity of the white carbon black product prepared by this process is relatively low, only reaching 98%.

[0005] The patented technology of "A method for leaching vanadium from vanadium-bearing shale ore" (CN 102031367A) involves crushing and grinding the vanadium-bearing shale ore, adding a leaching solution prepared with ammonium persulfate and mixed alkali, leaching at normal temperature and pressure, separating the solid and liquid after leaching to obtain a vanadium-containing leaching solution, purifying and adjusting the pH value of the leaching solution, enriching vanadium ions to obtain a vanadium precipitation mother liquor, removing impurities such as silicon and phosphorus from the vanadium precipitation mother liquor and then adding ammonia water or ammonium salt to obtain ammonium polyvanadate precipitate, and calcining the ammonium polyvanadate to obtain vanadium pentoxide. The process flow is shortened, the impurity treatment operation is simple, and the production cost can be reduced. However, for every 1 ton of V2O5 produced, approximately 46.39 - 59.67 tons of vanadium extraction tailings are generated, and the amount of tailings is relatively large.

[0006] Wang Xuewen et al. (Wang Xuewen, Wang Huaguang, Gao Daxiong. A clean technology to separate and recover vanadium and chromium from chromate solutions[J]. Hydrometallurgy, 2018, 177: 94 - 99.) precipitated a mixture of polyvanadic acid and sodium polyvanadate from a Na3VO4 solution by hydrolysis, and obtained V2O5 after calcining and washing it. Under the condition that the pH value is 3.8 - 4.5, Fe 2+ or Fe 3+ was added to remove vanadium residues in the vanadium precipitation mother liquor, and then Na2SO3 was used to reduce Cr(Ⅵ) in the solution to Cr(Ⅲ), and Cr2O3·xH2O precipitate was formed under the conditions of 90℃ and pH > 8.5. The chromium oxide hydrate can be processed to obtain Cr2O3. However, the purity of the obtained vanadium pentoxide product is 98.6%, and the purity of the chromium sesquioxide product is 98.7%, and the purities are both relatively low.

[0007] The patented technology of "A production process for extracting aluminum, vanadium, molybdenum, and nickel elements from black shale without three-waste emissions" (CN 104152687B) involves aging, leaching, and solid-liquid separation of the vanadium shale, adding ammonium salt or potassium salt to the solution to form alum crystals, then oxidizing the solution and using resin adsorption and desorption to obtain a vanadium-rich solution, precipitating vanadium with ammonium salt to form vanadium pentoxide, and then adjusting the pH to form molybdic acid crystals and evaporating and concentrating to form nickel sulfate crystals. However, the recovery rate of aluminum is less than 70%, and the recovery rate is relatively low.

[0008] In summary, the existing vanadium extraction processes from shale still have technical defects such as low leaching rate, large amount of slag, low product purity, and low recovery rate. Summary of the Invention

[0009] The present invention aims to overcome the defects of the prior art, and the purpose is to provide a method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale with high leaching rate, small slag amount, high product purity, and high recovery rate.

[0010] To achieve the above object, the specific steps of the technical solution adopted by the present invention are as follows:

[0011] Step 1: Mix vanadium shale fine abrasive and sodium hydroxide according to the mass ratio of vanadium shale fine abrasive to sodium hydroxide of 1:0.2 - 5, roast, leach in a water bath, and perform solid-liquid separation to obtain vanadium shale alkaline leaching solution.

[0012] Charge materials according to the mass ratio of the sum of cetyltrimethylammonium bromide and sodium carboxymethylcellulose to the mass of silicon in the vanadium shale alkaline leaching solution of 1 - 10:100, mix to obtain a mixed solution; wherein, the molar ratio of cetyltrimethylammonium bromide to sodium carboxymethylcellulose is 1:1 - 10; then adjust the pH value of the mixed solution to 6.0 - 10.0 with sulfuric acid with a concentration of 30 - 50 vol%, place it in a water bath for reaction, and perform solid-liquid separation to obtain desiliconized solution and silicon precursor I.

[0013] Wash silicon precursor I with sulfuric acid with a concentration of 5 - 15 vol% for 1 - 5 times to obtain silicon precursor II and acid washing solution.

[0014] Wash silicon precursor II with clear water for 1 - 5 times to obtain silicon precursor III and water washing solution.

[0015] Mix the acid washing solution and the water washing solution to obtain a washing solution.

[0016] Step 2: Adjust the pH of the desiliconized solution to 8.0 - 12.0 with sodium hydroxide solution to obtain the desiliconized solution with adjusted pH, and then co-extract vanadium and chromium in the desiliconized solution with adjusted pH according to the volume ratio of blank organic phase to the desiliconized solution with adjusted pH of 1:0.1 - 10. The co-extraction time is 1 - 9 min to obtain vanadium-chromium organic phase.

[0017] Adjust the pH of the washing solution to 1.0 - 2.0 with sodium hydroxide to obtain the washing solution with adjusted pH, and then extract and separate vanadium and aluminum in the washing solution with adjusted pH according to the volume ratio of blank organic phase to the washing solution with adjusted pH of 1:0.1 - 10. The extraction and separation time is 1 - 9 min to obtain vanadium-rich organic phase and aluminum-containing raffinate.

[0018] Charge materials according to the volume ratio of the vanadium-rich organic phase to the vanadium-chromium organic phase of 1:1 - 3, mix to obtain a mixed organic phase; then perform acid back-extraction on the mixed organic phase with a sulfuric acid solution with a concentration of 0.5 - 2.5 mol / L to obtain vanadium-rich solution and chromium-containing organic phase.

[0019] The chromium-containing organic phase is subjected to alkaline back-extraction with a sodium hydroxide solution having a concentration of 0.5 to 2.5 mol / L to obtain a chromium-rich solution and a lean organic phase.

[0020] Step 3: Wash the lean organic phase 2 to 4 times with sulfuric acid having a concentration of 5 to 15 vol% to obtain a regenerated organic phase, and return the regenerated organic phase to Step 2 to replace the blank organic phase for cyclic extraction of vanadium and chromium and vanadium and aluminum. Among them, the volume ratio of sulfuric acid having a concentration of 5 to 15 vol% to the lean organic phase is 1:1 to 10.

[0021] Step 4: Calcinate the silica precursor III at 550 to 850 °C for 0.5 to 2 h to obtain a white carbon black product.

[0022] Adjust the pH of the aluminum-containing raffinate to 5 to 6 with sodium hydroxide to form aluminum hydroxide precipitate, and calcine it at 600 to 800 °C for 0.5 to 2 h to obtain an aluminum oxide product.

[0023] Adjust the pH of the vanadium-rich solution to 1.8 to 2.0 with ammonia water, precipitate vanadium at 90 to 95 °C for 1.5 to 2.0 h to obtain ammonium polyvanadate, and calcine the ammonium polyvanadate at 500 to 600 °C for 0.5 to 2 h to obtain a vanadium pentoxide product.

[0024] Add sodium sulfite to the chromium-rich solution, adjust the pH to 8 to 10 to form chromium hydroxide, and calcine the chromium hydroxide at 800 to 1000 °C for 1.5 to 3.0 h to obtain a chromium sesquioxide product.

[0025] In this technical solution:

[0026] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of less than 74 μm accounting for 75 wt%. Among them, the vanadium shale: V2O5 is 0.50 to 1.8 wt%, SiO2 is 45 to 60 wt%, Al2O3 is 5 to 10 wt%, Cr2O3 is 0.1 to 1.0 wt%, K2O is 2 to 6 wt%, CaO is 3 to 8 wt%, and Na2O is 0.2 to 0.6 wt%.

[0027] The temperature of the roasting is 400 to 600 °C, and the time of the roasting is 0.5 to 2 h.

[0028] The liquid-solid ratio of the water leaching is 1 to 4:1, the temperature of the water leaching is 25 to 95 °C, and the time of the water leaching is 0.5 to 2 h.

[0029] The temperature of the reaction in the water bath is 50 to 95 °C, and the time is 60 to 120 min.

[0030] The blank organic phase refers to the organic phase containing an amine extractant, a synergistic extractant, and sulfonated kerosene; wherein: the proportion of the amine extractant in the blank organic phase is 5-25 vol%, the proportion of the synergistic extractant in the blank organic phase is 5-15 vol%, and the rest is sulfonated kerosene.

[0031] The amine extractant is one of N235, N1923, and N263; the synergistic extractant is one of sec-octanol and TBP.

[0032] The acid stripping is carried out with a sulfuric acid solution. The acid consumption for acid stripping is 1.0-2.5 mol / L, the phase ratio O / A for acid stripping is 1-5:1, and the time for acid stripping is 15-30 min.

[0033] The alkali stripping is carried out with a sodium hydroxide solution. The alkali consumption for alkali stripping is 0.5-2.0 mol / L, the phase ratio O / A for alkali stripping is 1-5:1, and the time for alkali stripping is 5-20 min.

[0034] Compared with the prior art, the advantages of the present invention are as follows:

[0035] 1. The present invention introduces molten alkali, causing local deformation of the fine vanadium shale abrasive, thereby achieving complete decomposition of the fine vanadium shale abrasive. During the transformation of the fine vanadium shale abrasive into Na2SiO3 and anorthite, the defects of the fine vanadium shale abrasive are enhanced, promoting the dissolution of silicon, resulting in the expansion and cracking of the fine vanadium shale abrasive. Therefore, more cracks appear in the fine vanadium shale abrasive, and it becomes more porous, strengthening the release of vanadium and effectively promoting the improvement of the vanadium and silicon leaching rates.

[0036] 2. The present invention introduces cetyltrimethylammonium bromide and sodium carboxymethyl cellulose. During the production of silica white, the two act on silica white in the form of van der Waals forces and hydrogen bonds, alternately adsorbing on the surface of silica white, hindering the adsorption of impurity ions on the surface of silica white, thereby improving the purity of the silica white product, and the purity of the silica white (silicon dioxide) product is higher than 99%. When extracting and separating vanadium and aluminum, vanadium in the solution forms a V-O bond with the amine extractant, enriching vanadium in the organic phase, while aluminum cannot form a bond with the amine extractant, reducing the ion concentration in the solution, thereby improving the purity of aluminum trioxide, and the purity of the aluminum trioxide product is higher than 98.8%. When co-extracting vanadium and chromium, vanadium binds to the amine extractant through a V-O bond, and chromium binds to the amine extractant through a Cr-O bond. Vanadium and chromium are enriched in the organic phase. During acid stripping, the acid breaks the V-O bond, while the Cr-O bond remains unchanged, enriching vanadium in the vanadium-rich solution. During alkali stripping, the Cr-O bond is broken, enriching chromium in the chromium-rich solution, thereby improving the purity of vanadium pentoxide and chromium trioxide products; the purity of the vanadium pentoxide product is higher than 98.5%, and the purity of the chromium trioxide product is higher than 98.8%.

[0037] 3. The improvement of the vanadium and silicon leaching rates in the present invention reduces the remaining vanadium extraction tailings. For every 1 ton of V2O5 produced by the present invention, 34.56 tons of vanadium extraction tailings are generated, which is a 25.5% - 42.08% reduction in the amount of tailings compared to the general alkali leaching process. In contrast, for every 1 ton of V2O5 extracted by the traditional shale vanadium extraction process, 120 - 150 tons of tailings are generated. Compared with this, the amount of generated tailings is reduced by 71.2% - 76.96%.

[0038] 4. The present invention adopts a cascade separation process, which reduces the adsorption of vanadium, aluminum, and chromium during the preparation of silicon products. In the subsequent extraction process, through countercurrent extraction, 99.9% extraction and stripping of vanadium and chromium in the desiliconized liquid are achieved, fully enriching vanadium and chromium. For every 1000 tons of vanadium shale processed by the present invention: 13.23 tons of vanadium pentoxide products, 381.75 tons of silicon dioxide products, 18.10 tons of aluminum oxide products, and 2.65 tons of chromium oxide products are produced; the recovery rate of vanadium is higher than 89.8%, the recovery rate of silicon is higher than 90.8%, the recovery rate of aluminum is higher than 87.9%, and the recovery rate of chromium is higher than 90.4%.

[0039] Therefore, the present invention has the characteristics of high leaching rate, less tailings, high product purity, and high recovery rate. Specific Embodiments

[0040] To facilitate the understanding of the present invention, the following will describe the present invention more comprehensively and meticulously in combination with specific embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0041] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and do not limit the protection scope of the present invention.

[0042] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0043] A method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. The steps of the method described in this specific embodiment are as follows:

[0044] Step 1: Mix vanadium shale fine abrasive and sodium hydroxide according to a mass ratio of vanadium shale fine abrasive : sodium hydroxide of 1 : 0.2 - 5, roast, leach in a water bath, and perform solid-liquid separation to obtain vanadium shale alkali leaching liquid.

[0045] Charge materials according to the mass ratio of the sum of cetyltrimethylammonium bromide and sodium carboxymethyl cellulose to silicon in the alkaline leaching solution of vanadium shale of 1-10:100, mix to obtain a mixed solution; wherein, the molar ratio of cetyltrimethylammonium bromide to sodium carboxymethyl cellulose is 1:1-10; then adjust the pH value of the mixed solution to 6.0-10.0 with sulfuric acid with a concentration of 30-50 vol%, place it in a water bath to react, and perform solid-liquid separation to obtain a desilicified solution and a silica precursor I.

[0046] Wash the silica precursor I 1-5 times with sulfuric acid with a concentration of 5-15 vol% to obtain a silica precursor II and an acid washing solution.

[0047] Wash the silica precursor II 1-5 times with clear water to obtain a silica precursor III and a water washing solution.

[0048] Mix the acid washing solution and the water washing solution to obtain a washing solution.

[0049] Step 2: Adjust the pH of the desilicified solution to 8.0-12.0 with a sodium hydroxide solution to obtain a desilicified solution with adjusted pH, and then co-extract vanadium and chromium in the desilicified solution with adjusted pH according to the volume ratio of the blank organic phase to the desilicified solution with adjusted pH of 1:0.1-10. The co-extraction time is 1-9 min to obtain a vanadium-chromium organic phase.

[0050] Adjust the pH of the washing solution to 1.0-2.0 with sodium hydroxide to obtain a washing solution with adjusted pH, and then extract and separate vanadium and aluminum in the washing solution with adjusted pH with the blank organic phase according to the volume ratio of the blank organic phase to the washing solution with adjusted pH of 1:0.1-10. The extraction and separation time is 1-9 min to obtain a vanadium-rich organic phase and an aluminum-containing raffinate.

[0051] Charge materials according to the volume ratio of the vanadium-rich organic phase to the vanadium-chromium organic phase of 1:1-3, mix to obtain a mixed organic phase; then perform acid back-extraction on the mixed organic phase with a sulfuric acid solution with a concentration of 0.5-2.5 mol / L to obtain a vanadium-rich solution and a chromium-containing organic phase.

[0052] Perform alkaline back-extraction on the chromium-containing organic phase with a sodium hydroxide solution with a concentration of 0.5-2.5 mol / L to obtain a chromium-rich solution and a lean organic phase.

[0053] Step 3: Wash the lean organic phase 2-4 times with sulfuric acid with a concentration of 5-15 vol% to obtain a regenerated organic phase, and return the regenerated organic phase to Step 2 to replace the blank organic phase for cyclic extraction of vanadium-chromium and vanadium-aluminum, wherein the volume ratio of sulfuric acid with a concentration of 5-15 vol% to the lean organic phase is 1:1-10.

[0054] Step 4: Calcinate the silica precursor III at 550-850 °C for 0.5-2 h to obtain a white carbon black product.

[0055] Adjust the pH of the aluminum-containing raffinate to 5 - 6 with sodium hydroxide to form aluminum hydroxide precipitate, and calcine it at 600 - 800 °C for 0.5 - 2 h to obtain aluminum oxide product.

[0056] Adjust the pH of the vanadium-rich solution to 1.8 - 2.0 with ammonia water, precipitate vanadium at 90 - 95 °C for 1.5 - 2.0 h to obtain ammonium polyvanadate, and calcine ammonium polyvanadate at 500 - 600 °C for 0.5 - 2 h to obtain vanadium pentoxide.

[0057] Add sodium sulfite to the chromium-rich solution, adjust the pH to 8 - 10 to form chromium hydroxide, and calcine chromium hydroxide at 800 - 1000 °C for 1.5 - 3.0 h to obtain chromium oxide.

[0058] In this specific embodiment:

[0059] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of <74 μm accounting for 75 wt%; among them, the vanadium shale: V2O5 is 0.50 - 1.8 wt%, SiO2 is 45 - 60 wt%, Al2O3 is 5 - 10 wt%, Cr2O3 is 0.1 - 1.0 wt%, K2O is 2 - 6 wt%, CaO is 3 - 8 wt%, and Na2O is 0.2 - 0.6 wt%.

[0060] The roasting temperature is 400 - 600 °C, and the roasting time is 0.5 - 2 h.

[0061] The liquid-solid ratio of the water leaching is 1 - 4:1, the water leaching temperature is 25 - 95 °C, and the water leaching time is 0.5 - 2 h.

[0062] The reaction temperature in the water bath is 50 - 95 °C, and the time is 60 - 120 min.

[0063] The blank organic phase refers to the organic phase containing amine extractant, co-extractant, and sulfonated kerosene; among them: the proportion of amine extractant in the blank organic phase is 5 - 25 vol%, the proportion of co-extractant in the blank organic phase is 5 - 15 vol%, and the rest is sulfonated kerosene.

[0064] The amine extractant is one of N235, N1923, and N263; the co-extractant is one of sec-octanol and TBP.

[0065] The acid stripping is carried out with sulfuric acid solution. The acid consumption for acid stripping is 1.0 - 2.5 mol / L, the phase ratio O / A for acid stripping is 1 - 5:1, and the acid stripping time is 15 - 30 min.

[0066] The alkali back-extraction is carried out with a sodium hydroxide solution. The alkali dosage for the alkali back-extraction is 0.5 - 2.0 mol / L, the phase ratio O / A for the alkali back-extraction is 1 - 5:1, and the time for the alkali back-extraction is 5 - 20 min.

[0067] Example 1

[0068] A method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. The steps of the method in this example are as follows:

[0069] Step 1: Mix vanadium shale fine abrasive and sodium hydroxide according to a mass ratio of vanadium shale fine abrasive:sodium hydroxide of 1:0.2, roast, leach in a water bath, and perform solid-liquid separation to obtain a vanadium shale alkali leaching solution.

[0070] Charge materials according to a mass ratio of the sum of the mass of cetyltrimethylammonium bromide and sodium carboxymethylcellulose:silicon in the vanadium shale alkali leaching solution of 1:100, mix to obtain a mixed solution; among them, the molar ratio of cetyltrimethylammonium bromide:sodium carboxymethylcellulose is 1:1; then adjust the pH value of the mixed solution to 6.0 with sulfuric acid with a concentration of 30 vol%, place it in a water bath for reaction, and perform solid-liquid separation to obtain a desilicated solution and a silica precursor I.

[0071] Wash the silica precursor I once with sulfuric acid with a concentration of 5 vol% to obtain a silica precursor II and an acid washing solution.

[0072] Wash the silica precursor II once with clear water to obtain a silica precursor III and a water washing solution.

[0073] Mix the acid washing solution and the water washing solution to obtain a washing solution.

[0074] Step 2: Adjust the pH of the desilicated solution to 8.0 with a sodium hydroxide solution to obtain the desilicated solution with adjusted pH, and then co-extract vanadium and chromium in the desilicated solution with adjusted pH with a blank organic phase according to a volume ratio of blank organic phase:desilicated solution with adjusted pH of 1:10. The co-extraction time is 1 min to obtain a vanadium-chromium organic phase.

[0075] Adjust the pH of the washing solution to 1.0 with sodium hydroxide to obtain the washing solution with adjusted pH, and then extract and separate vanadium and aluminum in the washing solution with adjusted pH with a blank organic phase according to a volume ratio of blank organic phase:washing solution with adjusted pH of 1:10. The extraction and separation time is 1 min to obtain a vanadium-rich organic phase and an aluminum-containing raffinate.

[0076] Charge materials according to a volume ratio of the vanadium-rich organic phase:the vanadium-chromium organic phase of 1:1, mix to obtain a mixed organic phase; then perform acid back-extraction on the mixed organic phase with a sulfuric acid solution with a concentration of 0.5 mol / L to obtain a vanadium-rich solution and a chromium-containing organic phase.

[0077] The chromium-containing organic phase is subjected to alkaline back-extraction with a sodium hydroxide solution having a concentration of 0.5 mol / L to obtain a chromium-rich solution and a lean organic phase.

[0078] Step 3: The lean organic phase is washed twice with sulfuric acid having a concentration of 5 vol% to obtain a regenerated organic phase, and the regenerated organic phase is returned to Step 2 to replace the blank organic phase for cyclic extraction of vanadium and chromium and vanadium and aluminum. Among them, the volume ratio of sulfuric acid having a concentration of 5 vol% to the lean organic phase is 1:1.

[0079] Step 4: The silica precursor III is calcined at 550 °C for 0.5 h to obtain a white carbon black product.

[0080] The aluminum-containing raffinate is adjusted to pH 5 with sodium hydroxide to form aluminum hydroxide precipitate, and is calcined at 600 °C for 0.5 h to obtain an aluminum oxide product.

[0081] The vanadium-rich solution is adjusted to pH 1.8 with ammonia water, and vanadium is precipitated at 90 °C for 1.5 h to obtain ammonium polyvanadate. The ammonium polyvanadate is calcined at 500 °C for 0.5 h to obtain vanadium pentoxide.

[0082] Sodium sulfite is added to the chromium-rich solution, and the pH is adjusted to 8 to form chromium hydroxide. The chromium hydroxide is calcined at 800 °C for 1.5 h to obtain chromium trioxide.

[0083] In this example:

[0084] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of <74 μm accounting for 75 wt%. Among them, the vanadium shale: V2O5 is 0.50 wt%, SiO2 is 45 wt%, Al2O3 is 5 wt%, Cr2O3 is 0.1 wt%, K2O is 2 wt%, CaO is 3 wt%, and Na2O is 0.2 wt%.

[0085] The temperature of the roasting is 400 °C, and the time of the roasting is 0.5 h.

[0086] The liquid-solid ratio of the water leaching is 4:1, the temperature of the water leaching is 25 °C, and the time of the water leaching is 0.5 h.

[0087] The temperature of the reaction in the water bath is 50 °C, and the time is 60 min.

[0088] The blank organic phase refers to an organic phase containing an amine extractant, a co-extractant, and sulfonated kerosene. Among them: the proportion of the amine extractant in the blank organic phase is 5 vol%, the proportion of the co-extractant in the blank organic phase is 5 vol%, and the rest is sulfonated kerosene;

[0089] The amine extractant is N235; the co-extractant is sec-octanol.

[0090] The acid stripping is carried out using a sulfuric acid solution. The acid dosage for acid stripping is 1.0 mol / L, the phase ratio O / A for acid stripping is 1:1, and the time for acid stripping is 15 min.

[0091] The base stripping is carried out using a sodium hydroxide solution. The base dosage for base stripping is 0.5 mol / L, the phase ratio O / A for base stripping is 1:1, and the time for base stripping is 5 min.

[0092] In this example, after detection: the recovery rate of vanadium is 95.88%, the recovery rate of silicon is 99.10%, the recovery rate of aluminum is 88.43%, and the recovery rate of chromium is 90.41%; the purity of the V2O5 product is 99.28%, the purity of the white carbon black product is 99.42%, the purity of the Al2O3 product is 98.94%, and the purity of the Cr2O3 product is 99.01%.

[0093] Example 2

[0094] A method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. The steps of the method in this example are as follows:

[0095] Step 1: Mix vanadium shale fine grinding material and sodium hydroxide according to the mass ratio of vanadium shale fine grinding material to sodium hydroxide of 1:1, roast, leach in a water bath, and perform solid-liquid separation to obtain vanadium shale alkaline leaching solution.

[0096] Charge materials according to the mass ratio of the sum of cetyltrimethylammonium bromide and sodium carboxymethylcellulose to the silicon in the vanadium shale alkaline leaching solution of 4:100, mix to obtain a mixed solution; wherein, the molar ratio of cetyltrimethylammonium bromide to sodium carboxymethylcellulose is 1:4; then adjust the pH value of the mixed solution to 8.0 with sulfuric acid with a concentration of 35 vol%, place it in a water bath for reaction, and perform solid-liquid separation to obtain a desiliconized solution and a silica precursor I.

[0097] Wash the silica precursor I three times with sulfuric acid with a concentration of 8 vol% to obtain a silica precursor II and an acid washing solution.

[0098] Wash the silica precursor II twice with clear water to obtain a silica precursor III and a water washing solution.

[0099] Mix the acid washing solution and the water washing solution to obtain a washing solution.

[0100] Step 2: Adjust the pH of the desiliconized solution to 9.0 with a sodium hydroxide solution to obtain the desiliconized solution with adjusted pH. Then, according to the volume ratio of the blank organic phase to the desiliconized solution with adjusted pH of 1:1, co-extract vanadium and chromium in the desiliconized solution with adjusted pH using the blank organic phase. The co-extraction time is 3 min to obtain a vanadium-chromium organic phase.

[0101] Adjust the pH of the washing solution to 1.6 with sodium hydroxide to obtain the washing solution after pH adjustment. Then, according to the volume ratio of blank organic phase to the washing solution after pH adjustment being 1:1, extract and separate vanadium and aluminum in the washing solution after pH adjustment with the blank organic phase. The extraction and separation time is 3 min to obtain a vanadium-rich organic phase and an aluminum-containing raffinate.

[0102] Charge materials according to the volume ratio of the vanadium-rich organic phase to the vanadium-chromium organic phase being 1:2, and mix to obtain a mixed organic phase. Then, perform acid back-extraction on the mixed organic phase with a sulfuric acid solution having a concentration of 1.0 mol / L to obtain a vanadium-rich solution and a chromium-containing organic phase.

[0103] Perform alkali back-extraction on the chromium-containing organic phase with a sodium hydroxide solution having a concentration of 1.0 mol / L to obtain a chromium-rich solution and a lean organic phase.

[0104] Step 3: Wash the lean organic phase 3 times with sulfuric acid having a concentration of 10 vol% to obtain a regenerated organic phase, and return the regenerated organic phase to Step 2 to replace the blank organic phase for cyclic extraction of vanadium-chromium and vanadium-aluminum. Among them, the volume ratio of sulfuric acid having a concentration of 8 vol% to the lean organic phase is 1:4.

[0105] Calcine the silica precursor III at 650 °C for 1.0 h to obtain a white carbon black product.

[0106] Adjust the pH of the aluminum-containing raffinate to 5.2 with sodium hydroxide to form aluminum hydroxide precipitate, and calcine it at 650 °C for 1.0 h to obtain an aluminum oxide product.

[0107] Adjust the pH of the vanadium-rich solution to 1.9 with ammonia water, precipitate vanadium at 92 °C for 1.6 h to obtain ammonium polyvanadate, and calcine the ammonium polyvanadate at 540 °C for 1.0 h to obtain vanadium pentoxide.

[0108] Add sodium sulfite to the chromium-rich solution, adjust the pH to 9 to form chromium hydroxide, and calcine the chromium hydroxide at 900 °C for 2.0 h to obtain chromium trioxide.

[0109] In this embodiment:

[0110] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of <74 μm accounting for 75 wt%. Among them, the vanadium shale: V2O5 is 1.0 wt%, SiO2 is 50 wt%, Al2O3 is 7 wt%, Cr2O3 is 0.5 wt%, K2O is 3 wt%, CaO is 5 wt%, and Na2O is 0.4 wt%.

[0111] The temperature of the roasting is 450 °C, and the roasting time is 1.0 h.

[0112] The liquid-solid ratio of the water immersion is 3:1, the temperature of the water immersion is 60 °C, and the time of the water immersion is 1.0 h.

[0113] The temperature of the reaction in the water bath is 65 °C, and the time is 80 min.

[0114] The blank organic phase refers to the organic phase containing an amine extractant, a synergistic extractant, and sulfonated kerosene; among them: the proportion of the amine extractant in the blank organic phase is 10 vol%, the proportion of the synergistic extractant in the blank organic phase is 10 vol%, and the rest is sulfonated kerosene.

[0115] The amine extractant is N1923; the synergistic extractant is TBP.

[0116] The acid stripping is carried out using a sulfuric acid solution. The acid consumption for the acid stripping is 1.5 mol / L, the phase ratio O / A for the acid stripping is 3:1, and the time for the acid stripping is 20 min.

[0117] The alkali stripping is carried out using a sodium hydroxide solution. The alkali consumption for the alkali stripping is 1.0 mol / L, the phase ratio O / A for the alkali stripping is 3:1, and the time for the alkali stripping is 10 min.

[0118] In this example, after detection: the recovery rate of vanadium is 89.88%, the recovery rate of silicon is 99.12%, the recovery rate of aluminum is 89.22%, and the recovery rate of chromium is 92.41%; the purity of the V2O5 product is 98.78%, the purity of the white carbon black product is 99.22%, the purity of the Al2O3 product is 98.84%, and the purity of the Cr2O3 product is 98.89%.

[0119] Example 3

[0120] A method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. The steps of the method in this example are:

[0121] Step 1. Preparation of the vanadium shale alkali leaching solution: Mix vanadium shale fine abrasive and sodium hydroxide according to the mass ratio of vanadium shale fine abrasive: sodium hydroxide of 1:2, roast, perform water immersion in a water bath, and perform solid-liquid separation to obtain the vanadium shale alkali leaching solution.

[0122] Charge materials according to the mass ratio of the sum of cetyltrimethylammonium bromide and sodium carboxymethylcellulose: the mass of silicon in the vanadium shale alkali leaching solution of 7:100, mix to obtain a mixed solution; among them, the molar ratio of cetyltrimethylammonium bromide: sodium carboxymethylcellulose is 1:8; then adjust the pH value of the mixed solution to 9.0 with sulfuric acid with a concentration of 40 vol%, place it in a water bath for reaction, and perform solid-liquid separation to obtain a desiliconized solution and a silica precursor I.

[0123] The silica precursor I was washed 4 times with sulfuric acid at a concentration of 10 vol%, obtaining the silica precursor II and the acid washing solution.

[0124] The silica precursor II was washed 3 times with clear water, obtaining the silica precursor III and the water washing solution.

[0125] The acid washing solution and the water washing solution were mixed to obtain the washing solution.

[0126] Step 2: The pH of the desilication solution was adjusted to 10 with sodium hydroxide solution, obtaining the desilication solution with adjusted pH. Then, according to the volume ratio of blank organic phase: desilication solution with adjusted pH being 1:0.2, the vanadium and chromium in the desilication solution with adjusted pH were co-extracted with the blank organic phase for 5 min, obtaining the vanadium-chromium organic phase.

[0127] The pH of the washing solution was adjusted to 1.8 with sodium hydroxide, obtaining the washing solution with adjusted pH. Then, according to the volume ratio of blank organic phase: washing solution with adjusted pH being 1:0.2, the vanadium and aluminum in the washing solution with adjusted pH were extracted and separated with the blank organic phase for 7 min, obtaining the vanadium-rich organic phase and the aluminum-containing raffinate.

[0128] According to the volume ratio of the vanadium-rich organic phase: the vanadium-chromium organic phase being 1:2, ingredients were prepared and mixed to obtain the mixed organic phase; then, the mixed organic phase was acid back-extracted with a sulfuric acid solution at a concentration of 2.0 mol / L to obtain the vanadium-rich solution and the chromium-containing organic phase.

[0129] The chromium-containing organic phase was alkali back-extracted with a sodium hydroxide solution at a concentration of 1.5 mol / L to obtain the chromium-rich solution and the lean organic phase.

[0130] Step 3: The lean organic phase was washed 4 times with sulfuric acid at a concentration of 12.5 vol% to obtain the regenerated organic phase, and the regenerated organic phase was returned to Step 2 to replace the blank organic phase for cyclic extraction of vanadium-chromium and vanadium-aluminum, where the volume ratio of sulfuric acid at a concentration of 12 vol%: lean organic phase was 1:7.

[0131] Step 4: The silica precursor III was calcined at 750 °C for 1.5 h to obtain the white carbon black product.

[0132] The pH of the aluminum-containing raffinate was adjusted to 5.6 with sodium hydroxide to form aluminum hydroxide precipitate, and it was calcined at 700 °C for 1.5 h to obtain the aluminum oxide product.

[0133] The pH of the vanadium-rich solution was adjusted to 1.95 with ammonia water, and vanadium was precipitated at 94 °C for 1.8 h to obtain ammonium polyvanadate. The ammonium polyvanadate was calcined at 580 °C for 1.5 h to obtain vanadium pentoxide.

[0134] Sodium sulfite is added to the chromium-rich solution, and the pH is adjusted to 9.5 to produce chromium hydroxide. The chromium hydroxide is calcined at 950 °C for 2.5 h to obtain chromium sesquioxide.

[0135] In this example:

[0136] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of <74 μm accounting for 75 wt%; among them, the vanadium shale contains 1.5 wt% of V2O5, 55 wt% of SiO2, 9 wt% of Al2O3, 0.8 wt% of Cr2O3, 4 wt% of K2O, 7 wt% of CaO, and 0.5 wt% of Na2O.

[0137] The roasting temperature is 500 °C and the roasting time is 1.5 h.

[0138] The liquid-solid ratio of the water leaching is 2:1, the water leaching temperature is 80 °C, and the water leaching time is 1.5 h.

[0139] The reaction temperature in the water bath is 75 °C and the time is 100 min.

[0140] The blank organic phase refers to the organic phase containing an amine extractant, a synergistic extractant, and sulfonated kerosene; among them: the proportion of the amine extractant in the blank organic phase is 20 vol%, the proportion of the synergistic extractant in the blank organic phase is 12.5 vol%, and the rest is sulfonated kerosene.

[0141] The amine extractant is N263; the synergistic extractant is sec-octanol.

[0142] The acid stripping is carried out using a sulfuric acid solution. The acid consumption for acid stripping is 2.0 mol / L, the phase ratio O / A for acid stripping is 4:1, and the acid stripping time is 25 min.

[0143] The base stripping is carried out using a sodium hydroxide solution. The base consumption for base stripping is 1.5 mol / L, the phase ratio O / A for base stripping is 4:1, and the base stripping time is 15 min.

[0144] This example is detected: the recovery rate of vanadium is 96.94%, the recovery rate of silicon is 90.86%, the recovery rate of aluminum is 88.24%, and the recovery rate of chromium is 91.23%; the purity of the V2O5 product is 99.30%, the purity of the white carbon black product is 99.01%, the purity of the Al2O3 product is 98.90%, and the purity of the Cr2O3 product is 99.12%.

[0145] Example 4

[0146] A method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale. The steps of the method in this example are:

[0147] Step 1: Mix vanadium shale fine abrasive and sodium hydroxide in a mass ratio of 1:5, roast, soak in water in a water bath, and perform solid-liquid separation to obtain the vanadium shale alkali leaching solution.

[0148] Weigh materials according to the mass ratio of the sum of cetyltrimethylammonium bromide and sodium carboxymethyl cellulose to the silicon in the vanadium shale alkali leaching solution of 10:100, mix to obtain a mixed solution; among them, the molar ratio of cetyltrimethylammonium bromide to sodium carboxymethyl cellulose is 1:10; then adjust the pH value of the mixed solution to 10.0 with sulfuric acid with a concentration of 50 vol%, place it in a water bath for reaction, and perform solid-liquid separation to obtain a desiliconized solution and a silica precursor I.

[0149] Wash the silica precursor I 5 times with sulfuric acid with a concentration of 15 vol% to obtain a silica precursor II and an acid washing solution.

[0150] Wash the silica precursor II 5 times with water to obtain a silica precursor III and a water washing solution.

[0151] Mix the acid washing solution and the water washing solution to obtain a washing solution.

[0152] Step 2: Adjust the pH of the desiliconized solution to 12.0 with a sodium hydroxide solution to obtain the desiliconized solution with adjusted pH, and then co-extract vanadium and chromium in the desiliconized solution with adjusted pH with a blank organic phase according to the volume ratio of the blank organic phase to the desiliconized solution with adjusted pH of 1:0.1. The co-extraction time is 9 min to obtain a vanadium-chromium organic phase.

[0153] Adjust the pH of the washing solution to 2.0 with sodium hydroxide to obtain the washing solution with adjusted pH, and then extract and separate vanadium and aluminum in the washing solution with adjusted pH with a blank organic phase according to the volume ratio of the blank organic phase to the washing solution with adjusted pH of 1:0.1. The extraction and separation time is 9 min to obtain a vanadium-rich organic phase and an aluminum-containing raffinate.

[0154] Weigh materials according to the volume ratio of the vanadium-rich organic phase to the vanadium-chromium organic phase of 1:3, mix to obtain a mixed organic phase; then perform acid back-extraction on the mixed organic phase with a sulfuric acid solution with a concentration of 2.5 mol / L to obtain a vanadium-rich solution and a chromium-containing organic phase.

[0155] Perform alkali back-extraction on the chromium-containing organic phase with a sodium hydroxide solution with a concentration of 2.5 mol / L to obtain a chromium-rich solution and a lean organic phase.

[0156] Step 3: Wash the lean organic phase 4 times with sulfuric acid with a concentration of 15 vol% to obtain a regenerated organic phase, and return the regenerated organic phase to Step 2 to replace the blank organic phase for cyclic extraction of vanadium-chromium and vanadium-aluminum. Among them, the volume ratio of sulfuric acid with a concentration of 15 vol% to the lean organic phase is 1:10.

[0157] Step 4: Calcinate the silica precursor III at 850 °C for 2 h to obtain a precipitated silica product.

[0158] Adjust the pH of the aluminum-containing raffinate to 6 with sodium hydroxide to form aluminum hydroxide precipitate, and calcinate it at 800 °C for 2 h to obtain an aluminum oxide product.

[0159] Adjust the pH of the vanadium-rich solution to 2.0 with ammonia water, precipitate vanadium at 95 °C for 2.0 h to obtain ammonium polyvanadate, and calcinate the ammonium polyvanadate at 600 °C for 2 h to obtain vanadium pentoxide.

[0160] Add sodium sulfite to the chromium-rich solution, adjust the pH to 10 to form chromium hydroxide, and calcinate the chromium hydroxide at 1000 °C for 3.0 h to obtain chromium sesquioxide.

[0161] In this example:

[0162] The vanadium shale fine abrasive is obtained by first decarbonizing the vanadium shale and then grinding it to a particle size of less than 74 μm, with 75 wt% of the particles meeting this size requirement. Among them, the vanadium shale contains 1.8 wt% V2O5, 60 wt% SiO2, 10 wt% Al2O3, 1.0 wt% Cr2O3, 6 wt% K2O, 8 wt% CaO, and 0.6 wt% Na2O.

[0163] The roasting temperature is 600 °C, and the roasting time is 2 h.

[0164] The liquid-solid ratio of the water leaching is 1:1, the water leaching temperature is 95 °C, and the water leaching time is 2.0 h.

[0165] The reaction temperature in the water bath is 95 °C, and the time is 120 min;

[0166] The blank organic phase refers to the organic phase containing an amine extractant, a synergistic extractant, and sulfonated kerosene. Among them: the proportion of the amine extractant in the blank organic phase is 25 vol%, the proportion of the synergistic extractant in the blank organic phase is 15 vol%, and the rest is sulfonated kerosene.

[0167] The amine extractant is N263; the synergistic extractant is TBP.

[0168] The acid stripping is carried out using a sulfuric acid solution. The acid consumption for acid stripping is 2.5 mol / L, the phase ratio O / A for acid stripping is 5:1, and the acid stripping time is 30 min.

[0169] The base stripping is carried out using a sodium hydroxide solution. The base consumption for base stripping is 2.0 mol / L, the phase ratio O / A for base stripping is 5:1, and the base stripping time is 20 min.

[0170] In this example, through detection: the recovery rate of vanadium is 92.15%, the recovery rate of silicon is 98.99%, the recovery rate of aluminum is 87.94%, and the recovery rate of chromium is 92.21%; the purity of the V2O5 product is 99.23%, the purity of the silica white product is 99.24%, the purity of the Al2O3 product is 98.86%, and the purity of the Cr2O3 product is 99.02%.

[0171] The advantages of this specific embodiment are as follows:

[0172] 1. This specific embodiment introduces molten alkali, causing local deformation of the finely ground vanadium shale, thereby achieving complete decomposition of the finely ground vanadium shale. During the transformation of the finely ground vanadium shale into Na2SiO3 and anorthite, the defects of the finely ground vanadium shale are enhanced, promoting the dissolution of silicon, resulting in the expansion and cracking of the finely ground vanadium shale. Therefore, more cracks appear in the finely ground vanadium shale, and it becomes more porous, strengthening the release of vanadium and effectively promoting the increase in the leaching rates of vanadium and silicon.

[0173] 2. This specific embodiment introduces cetyltrimethylammonium bromide and sodium carboxymethyl cellulose. During the production of silica white, the two act on silica white in the form of van der Waals forces and hydrogen bonds, alternately adsorbing on the surface of silica white, hindering the adsorption of impurity ions on the surface of silica white, thereby improving the purity of the silica white product, and the purity of the silica white (silicon dioxide) product is higher than 99%. When extracting and separating vanadium and aluminum, vanadium in the solution forms a V - O bond with the amine extractant, enriching vanadium into the organic phase, while aluminum cannot form a bond with the amine extractant, reducing the concentration of ions in the solution, thereby improving the purity of aluminum oxide, and the purity of the aluminum oxide product is higher than 98.8%. When co - extracting vanadium and chromium, vanadium binds to the amine extractant through a V - O bond, and chromium binds to the amine extractant through a Cr - O bond. Vanadium and chromium are enriched into the organic phase. During acid back - extraction, the acid breaks the V - O bond, while the Cr - O bond remains unchanged, enriching vanadium into the vanadium - rich solution. During alkali back - extraction, the Cr - O bond is broken, enriching chromium into the chromium - rich solution, thereby improving the purity of the vanadium pentoxide and chromium sesquioxide products; the purity of the vanadium pentoxide product is higher than 98.5%, and the purity of the chromium sesquioxide product is higher than 98.8%.

[0174] 3. The increase in the leaching rates of vanadium and silicon in this specific embodiment reduces the remaining vanadium - extraction tailings. This specific embodiment produces 34.56 tons of vanadium - extraction tailings per ton of V2O5 produced, a reduction of 25.5% - 42.08% in the amount of tailings compared to the general alkali - leaching process; while the traditional vanadium - extraction process from shale produces 120 - 150 tons of tailings per ton of V2O5 extracted. In comparison, the amount of tailings generated is reduced by 71.2% - 76.96%.

[0175] 4. This specific embodiment adopts a cascade separation process, reducing the adsorption of vanadium, aluminum, and chromium during the preparation of silicon products. In the subsequent extraction process, through countercurrent extraction, 99.9% extraction and stripping of vanadium and chromium in the desiliconized liquid are achieved, enriching vanadium and chromium sufficiently. For every 1000 tons of vanadium shale processed in this specific embodiment: 13.23 tons of vanadium pentoxide products, 381.75 tons of silicon dioxide products, 18.10 tons of aluminum oxide products, and 2.65 tons of chromium sesquioxide products are produced; the recovery rate of vanadium is higher than 89.8%, the recovery rate of silicon is higher than 90.8%, the recovery rate of aluminum is higher than 87.9%, and the recovery rate of chromium is higher than 90.4%.

[0176] Therefore, this specific embodiment features high leaching rate, less slag volume, high product purity, and high recovery rate.

Claims

1. A method for preparing vanadium, chromium, aluminum, and silicon products by stepwise separation of vanadium shale, characterized in that, The specific steps of the method are: Step 1, mixing ingredients according to the mass ratio of hexadecyltrimethylammonium bromide and sodium cellulose carboxylate: the mass ratio of silicon in the vanadium shale alkali leaching solution is 1-10:100, and obtaining a mixed solution; wherein the molar ratio of hexadecyltrimethylammonium bromide: sodium cellulose carboxylate is 1:1-10; adjusting the pH value of the mixed solution to 6.0-10.0 with sulfuric acid having a concentration of 30-50 vol%, placing the mixed solution in a water bath for reaction, and performing solid-liquid separation to obtain a desiliconization solution and a siliceous precursor I; The silicon precursor I is washed 1 to 5 times with sulfuric acid having a concentration of 5 to 15 vol% to obtain a silicon precursor II and an acid washing solution; Washing the silicon precursor II with clean water for 1 to 5 times to obtain silicon precursor III and a washing liquid; Mixing the acid wash solution and the water wash solution to obtain a washing solution; Step 2, preparing the vanadium-rich organic phase and the vanadium-chromium organic phase in a volume ratio of 1:1-3, mixing to obtain a mixed organic phase; then stripping the mixed organic phase with a sulfuric acid solution having a concentration of 0.5-2.5 mol / L to obtain a vanadium-rich solution and a chromium-containing organic phase; The chromium-containing organic phase is subjected to alkaline stripping with a sodium hydroxide solution having a concentration of 0.5 to 2.5 mol / L to obtain a chromium-rich solution and a lean organic phase; Step 3, washing the lean organic phase with 5-15 vol% sulfuric acid for 2-4 times to obtain a regenerated organic phase, returning the regenerated organic phase to step 2 to replace the blank organic phase for cyclic extraction of vanadium chromium and vanadium aluminum, wherein the volume ratio of 5-15 vol% sulfuric acid to the lean organic phase is 1:1-10; Step 4, calcining the siliceous precursor III at 550-850° C. for 0.5-2 h to obtain a white carbon black product; The aluminum-containing raffinate is adjusted to pH 5-6 with sodium hydroxide to generate aluminum hydroxide precipitate, which is calcined at 600-800°C for 0.5-2h to obtain an aluminum oxide product; The vanadium-rich solution is adjusted to a pH of 1.8 to 2.0 with ammonia water, vanadium is precipitated at 90 to 95° C. for 1.5 to 2.0 hours to obtain polyammonium vanadate, and the polyammonium vanadate is calcined at 500 to 600° C. for 0.5 to 2 hours to obtain vanadium pentoxide; Sodium sulfite is added to the chromium-rich solution to adjust the pH to 8-10 to generate chromium hydroxide, and the chromium hydroxide is calcined at 800-1000° C. for 1.5-3.0 hours to obtain chromium trioxide.

2. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, wherein The preparation of the vanadium shale alkali leaching solution is as follows: the vanadium shale fine ground material and sodium hydroxide are mixed evenly according to the mass ratio of vanadium shale fine ground material to sodium hydroxide of 1:0.2-0.5, roasted, immersed in a water bath, and separated into solid and liquid to obtain the vanadium shale alkali leaching solution; The vanadium shale fine abrasive is prepared by first decarburizing the vanadium shale and then grinding it to a particle size of less than 74 μm, which accounts for 75 wt% of the vanadium shale fine abrasive; wherein the vanadium shale comprises: 0.50-1.8 wt% of V2O5, 45-60 wt% of SiO2, 5-10 wt% of Al2O3, 0.1-1.0 wt% of Cr2O3, 2-6 wt% of K2O, 3-8 wt% of CaO, and 0.2-0.6 wt% of Na2O.

3. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 2, wherein The roasting temperature is 400 - 600 °C, and the roasting time is 0.5 - 2 h.

4. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 2, characterized in that, The liquid-solid ratio of water leaching is 1 - 4:1, the water leaching temperature is 25 - 95 °C, and the water leaching time is 0.5 - 2 h.

5. The method for preparing vanadium, chromium, aluminum, and silicon products by stepwise separation of vanadium shale according to claim 1, characterized in that, The reaction temperature in the water bath is 50 - 95 °C, and the time is 60 - 120 min.

6. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, wherein The blank organic phase refers to the organic phase containing an amine extractant, a co-extractant, and sulfonated kerosene; wherein: the proportion of the amine extractant in the blank organic phase is 5 - 25 vol%, the proportion of the co-extractant in the blank organic phase is 5 - 15 vol%, and the rest is sulfonated kerosene; The amine extractant is one of N235, N1923, and N263; the co-extractant is one of sec-octanol and TBP.

7. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, characterized in that, Preparation of the vanadium-chromium organic phase: Adjust the pH of the desiliconized solution to 8.0 - 12.0 with a sodium hydroxide solution to obtain the desiliconized solution with adjusted pH, and then co-extract vanadium and chromium in the desiliconized solution with adjusted pH using the blank organic phase at a volume ratio of blank organic phase:desiliconized solution with adjusted pH of 1:0.1 - 10 for 1 - 9 min to obtain the vanadium-chromium organic phase.

8. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, characterized in that, Preparation of the vanadium-rich organic phase: Adjust the pH of the washing solution to 1.0 - 2.0 with sodium hydroxide to obtain the washing solution with adjusted pH, and then extract and separate vanadium and aluminum in the washing solution with adjusted pH using the blank organic phase at a volume ratio of blank organic phase:washing solution with adjusted pH of 1:0.1 - 10 for 1 - 9 min to obtain the vanadium-rich organic phase and the aluminum-containing raffinate.

9. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, characterized in that, The acid back-extraction is carried out using a sulfuric acid solution. The acid consumption for acid back-extraction is 1.0 - 2.5 mol / L, the phase ratio O / A for acid back-extraction is 1 - 5:1, and the acid back-extraction time is 15 - 30 min.

10. The method for preparing vanadium, chromium, aluminum, and silicon products by cascade separation of vanadium shale according to claim 1, characterized in that, The base back-extraction is carried out using a sodium hydroxide solution. The base consumption for base back-extraction is 0.5 - 2.0 mol / L, the phase ratio O / A for base back-extraction is 1 - 5:1, and the base back-extraction time is 5 - 20 min.