Method for extracting white carbon black from shale vanadium extraction tailings

Abstract

The invention discloses a method for extracting white carbon black from shale vanadium extraction tailings. The method comprises the following steps: (1) crushing and screening the shale vanadium extraction tailings to obtain tailings powder; (2) uniformly mixing the tailing powder with a roasting additive, and then carrying out roasting treatment to obtain a roasted material; the roasting additive is prepared from alkali, CH3COONa and NaF; (3) leaching the roasted material, and carrying out solid-liquid separation to obtain a silicon-containing leachate; and (4) carrying out silicon precipitation, filtering, washing and drying treatment on the silicon-containing leachate to obtain the white carbon black. According to the method for extracting the white carbon black from the shale vanadium extraction tailings, the adopted roasting additives comprise the alkali, the CH3COONa and the NaF, and the alkali, the CH3COONa and the NaF have a synergistic effect, so that leaching of silicon dioxide in the shale vanadium extraction tailings can be promoted, leaching of impurities is reduced, the leaching rate of the silicon dioxide can be increased, and a high-dispersity and high-purity white carbon black product can be obtained.

Description

Technical Field

[0001] The invention belongs to the field of resource utilization of wastes, and in particular relates to a method for utilizing shale vanadium extraction tailings. Background Art

[0002] White carbon black, also known as hydrated silicon dioxide, is a new type of material formed by irregular accumulation of silicon dioxide tetrahedrons and water. It has multiple properties such as porosity, large specific surface area, high dispersibility, high temperature resistance, non-combustion and excellent electrical insulation. It is widely used in rubber, plastics, papermaking, ink, pesticides, feed, cosmetics, antibacterial materials and other chemical industries, especially in the field of silicone rubber, where it has an irreplaceable position and huge domestic demand.

[0003] Shale vanadium tailings are tailings produced after extracting vanadium metal from vanadium shale. The grade of vanadium in vanadium shale is low. On average, 120-150 tons of tailings will be produced for every ton of V2O5 produced by vanadium shale. The accumulation of a large amount of tailings not only occupies land and brings burden to the development of enterprises, but also under natural conditions, the heavy metal ions in the tailings are easily lost into the environment, causing environmental pollution. If the shale vanadium tailings can be prepared into white carbon black, it can not only solve the problem of tailings storage, but also produce qualified products to bring additional benefits.

[0004] Therefore, the use of shale tailings to prepare highly dispersed silica can not only realize the resource utilization of waste, but also provide a new source of raw materials for the production of silica.

[0005] Patent document CN110467186A discloses a method for extracting white carbon black from vanadium extraction tailings from shale. In this method, the silicon dioxide leaching rate can reach up to 95.2%, the reaction time is shortened to 60-150 minutes, and the SiO2 content in the product is detected to be above 92.8%. However, the purity of the white carbon black product obtained by this method is not high, the dispersibility is also poor, and the silicon dioxide leaching rate needs to be improved. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a method for extracting white carbon black from shale vanadium extraction tailings with high silica leaching rate, high purity and good dispersibility of the white carbon black product.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and screening the shale vanadium extraction tailings to obtain tailings powder; (2) uniformly mixing the tailings powder with a roasting additive, and then roasting the mixture to obtain a roasting material; the roasting additive includes alkali, CH3COONa and NaF; (3) leaching the roasted material, and when the leaching reaches equilibrium, separating the solid and the liquid to obtain a silicon-containing leaching solution; (4) The silicon-containing leaching solution is subjected to silicon precipitation, filtering, washing and drying treatment to obtain white carbon black.

[0008] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, the mass ratio of the tailings powder to the roasting additive is (1-20): (3-41).

[0009] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, the alkali is NaOH, and the mass ratio of NaOH, CH3COONa and NaF is (1-20): (1-10):1.

[0010] The present invention can achieve good leaching effect in the leaching process by controlling the mass ratio of tailings powder to the roasting additive and the mass ratio of each component in the roasting additive, while having lower cost. Too little use of NaOH, CH3COONa and NaF will reduce the silicon leaching rate, while too much use will increase the cost.

[0011] In the above method for extracting white carbon black from vanadium tailings from shale, preferably, during the roasting treatment, the roasting temperature is 700-900°C and the roasting time is 2-6 hours. Controlling within this temperature and time range can effectively achieve the best leaching effect. Too low a temperature will increase the difficulty of leaching, too high a temperature will increase energy consumption, too short a time will reduce the leaching efficiency, and too high a time will increase the cost.

[0012] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, the particle size of the tailings powder is 100-400 mesh. Controlling within this particle size range can effectively achieve the best leaching effect. Too fine a particle size will increase the grinding cost and energy consumption, while too large a particle size will increase the roasting cost and reduce the leaching effect.

[0013] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, when the roasted material is leached, the leaching liquid is a NaOH solution, and the mass ratio of NaOH in the NaOH solution to the roasted material is (0-1):1 (when the mass ratio is 0, the leaching liquid is an aqueous solution); the liquid-to-solid ratio of the NaOH solution to the roasted material is (1-20) mL:1 g.

[0014] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, when leaching the roasted material, the leaching temperature is 25-100° C. and the leaching time is 60-360 min.

[0015] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, during silicon precipitation, the silicon precipitation pH value endpoint of the silicon-containing leaching solution is controlled to be 3-9, and the silicon precipitation temperature is 25-95° C. Too low or too high temperature and pH are not conducive to silicon precipitation, and reduce the silicon precipitation rate.

[0016] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, during washing, the washing solution is at least one of sulfuric acid solution, anhydrous ethanol and pure water.

[0017] In the above method for extracting white carbon black from vanadium extraction tailings from shale, preferably, during the drying process, the drying temperature is 80-250° C. and the drying time is 60-480 min.

[0018] The shale vanadium extraction tailings of the present invention are tailings produced after vanadium extraction from stone coal vanadium ore, and the vanadium extraction process is the tailings produced after acid leaching of stone coal vanadium ore.

[0019] The roasting additive of the present invention includes alkali, CH3COONa and NaF, and the synergistic effect of the three can promote the leaching of silicon dioxide in shale vanadium extraction tailings, reduce the leaching of impurities, and be conducive to improving the leaching rate of silicon dioxide, and obtain a highly dispersed and high-purity white carbon black product. During the roasting process, CH3COONa and NaF will destroy the mineral crystal structure, making silicon dioxide more easily leached, and at the same time, adding alkali will effectively combine with the silicon dioxide after the structure is destroyed. Under the synergistic effect of the three substances, the roasting process generates water-soluble sodium silicate, which enters the aqueous solution during the leaching process, and the leaching of impurities is suppressed at the same time. The purity of the leachate is high, so the precipitation process does not need to be treated by impurity removal, and under suitable silicon precipitation temperature and pH conditions, a high-purity silicon dioxide product can be obtained, and the dispersibility of the obtained product is good. At the same time, the roasting additives of the present invention are all sodium salts, and new impurities will not be introduced, which is conducive to the subsequent silicon precipitation process.

[0020] In the present invention, in order to ensure the effect of the roasting additive, the amount of the roasting additive and the ratio of its components must be reasonably controlled. If the amount of the roasting additive is too small, it is difficult to improve the leaching rate of silicon dioxide in the tailings. Among the roasting additives, if the amounts of CH3COONa and NaF are too small, the crystal structure of the tailings cannot be well destroyed. For the tailings after acid leaching of vanadium, CH3COONa and NaF are both indispensable. The lack of any one of them will reduce the leaching rate of silicon dioxide in the tailings.

[0021] Compared with the prior art, the advantages of the present invention are: 1. The method for extracting white carbon black from vanadium extraction tailings of shale of the present invention comprises the following steps: firstly crushing the vanadium extraction tailings of shale to obtain tailings powder, then uniformly mixing the tailings powder with a roasting additive, then roasting the tailings powder, and then leaching and precipitating silicon to obtain a white carbon black product with high purity and high dispersion. During the roasting process, the synergistic effect of alkali, CH3COONa and NaF can be used to effectively destroy the structure of the tailings powder and reduce its structural stability, which is beneficial to the efficient leaching of silicon dioxide. Meanwhile, the leaching of impurities can also be suppressed, which is beneficial to obtaining a high-purity silicon product. The final results show that the method of the present invention can increase the silicon dioxide leaching rate to 96.91%, the silicon precipitation rate to 96.66%, the product purity to 95.43%, and the BET to 372.3m 2 / g, to produce highly dispersed and high-purity white carbon black products.

[0022] 2. The method of extracting white carbon black from shale vanadium extraction tailings of the present invention is simple and easy to operate, and effectively solves the problem of storage of shale vanadium extraction tailings. It has the characteristics of high tailings utilization rate, green environmental protection, high efficiency and energy saving, and also broadens the source of raw materials for preparing white carbon black, and has good application prospects. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0026] The shale vanadium extraction tailings in the following examples and comparative examples are tailings produced after vanadium extraction from a stone coal vanadium mine in Fenghuang, western Hunan, and the vanadium extraction process is the tailings after acid leaching of the stone coal vanadium mine.

[0027] Embodiment 1: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 100 mesh; (2) mixing the tailing powder in step (1) with NaOH, CH3COONa and NaF, wherein the mass ratio of the tailing powder to NaOH, CH3COONa and NaF is 20:20:10:1, to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 700° C. for 2 h to obtain a calcined material; (4) Leaching the roasted material in step (3), wherein the leaching solution is water, and the liquid-to-solid ratio is 1 mL:1 g; the leaching temperature is 25° C., and the leaching time is 60 min. When the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leaching solution; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH endpoint of the silicon-containing leachate to 3, and the silicon precipitation temperature to 35° C., to obtain a crude white carbon black product; (6) The crude silica product in step (5) is washed and dried with a 20 vol% sulfuric acid solution and pure water at a drying temperature of 80° C. for a drying time of 480 min to obtain a highly dispersed silica product.

[0028] In this embodiment, the silicon dioxide leaching rate is 95.88%, the silicon precipitation rate reaches 92.38%, the purity of the white carbon black product is 94.66%, and the BET is 182.9m 2 / g, to obtain a highly dispersed white carbon black product.

[0029] Embodiment 2: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 400 mesh; (2) mixing the tailing powder in step (1) with NaOH, CH3COONa and NaF in a mass ratio of 2:2:1:1 to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 900° C. for 6 h, and obtaining a calcined material after the calcination; (4) leaching the roasted material in step (3), wherein the leaching solution is a NaOH solution, the mass ratio of NaOH to the roasted material in the NaOH solution is 1:1, and the liquid-solid ratio is 3 mL:1 g; the leaching temperature is 100° C., the leaching time is 360 min, and when the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leachate; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH end point of the silicon-containing leachate to 5; and setting the silicon precipitation temperature to 65° C. to obtain a crude white carbon black product; (6) The crude silica product in step (5) is washed and dried with 20 vol% sulfuric acid solution, anhydrous ethanol and pure water at a drying temperature of 120°C for 180 min to obtain a highly dispersed silica product.

[0030] In this example, the silicon dioxide leaching rate is 96.91%, the silicon precipitation rate is 96.66%, the product purity is 95.43%, and the BET is 372.3m 2 / g, to obtain a highly dispersed white carbon black product.

[0031] Embodiment 3: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 200 mesh; (2) mixing the tailing powder in step (1) with NaOH, CH3COONa and NaF in a mass ratio of 2:1:1:1 to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 800° C. for 4 h to obtain a calcined material; (4) leaching the roasted material in step (3), wherein the leaching solution is a NaOH solution, the mass ratio of NaOH to the roasted material in the NaOH solution is 0.5:1, and the liquid-solid ratio is 5 mL:1 g; the leaching temperature is 80° C., the leaching time is 240 min, and when the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leachate; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH end point of the silicon-containing leachate to 7; and setting the silicon precipitation temperature to 80° C. to obtain a crude white carbon black product; (6) The crude silica product in step (5) is washed and dried with a 20 vol% sulfuric acid solution and anhydrous ethanol at a drying temperature of 250° C. for 60 min to obtain a highly dispersed silica product.

[0032] In this embodiment, the silicon dioxide leaching rate is 95.98%, the silicon precipitation rate reaches 96.43%, the product purity is 95.10%, and the BET is 267.8m 2 / g, to obtain a highly dispersed white carbon black product.

[0033] Comparative Example 1: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 400 mesh; (2) mixing the tailings powder in step (1) with NaOH in a mass ratio of 2:4 to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 900° C. for 6 h, and obtaining a calcined material after the calcination; (4) leaching the roasted material in step (3), wherein the leaching solution is a NaOH solution, the mass ratio of NaOH to the roasted material in the NaOH solution is 1:1, and the liquid-solid ratio is 3 mL:1 g; the leaching temperature is 100° C., the leaching time is 360 min, and when the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leachate; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH end point of the silicon-containing leachate to 5; and setting the silicon precipitation temperature to 65° C. to obtain a crude white carbon black product; (6) The crude white carbon black product in step (5) is washed and dried with 20 vol% sulfuric acid solution, anhydrous ethanol and pure water at a drying temperature of 120°C and a drying time of 180 min to obtain a white carbon black product.

[0034] In this comparative example, the silicon dioxide leaching rate is 76.60%, the silicon precipitation rate reaches 86.91%, the product purity is 82.33%, and the BET is 96.06m 2 / g.

[0035] Comparative Example 2: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 400 mesh; (2) mixing the tailing powder in step (1) with NaOH and NaF in a mass ratio of 2:2:2 to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 900° C. for 6 h, and obtaining a calcined material after the calcination; (4) leaching the roasted material in step (3), wherein the leaching solution is a NaOH solution, the mass ratio of NaOH to the roasted material in the NaOH solution is 1:1, and the liquid-solid ratio is 3 mL:1 g; the leaching temperature is 100° C., the leaching time is 360 min, and when the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leachate; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH end point of the silicon-containing leachate to 5; and setting the silicon precipitation temperature to 65° C. to obtain a crude white carbon black product; (6) The crude white carbon black product in step (5) is washed and dried with 20 vol% sulfuric acid solution, anhydrous ethanol and pure water at a drying temperature of 120°C and a drying time of 180 min to obtain a white carbon black product.

[0036] In this comparative example, the silicon dioxide leaching rate is 88.08%, the silicon precipitation rate reaches 90.03%, the product purity is 89.22%, and the BET is 243.8m 2 / g.

[0037] Comparative Example 3: A method for extracting white carbon black from shale vanadium extraction tailings comprises the following steps: (1) crushing, ball milling, drying and sieving the shale vanadium extraction tailings to obtain tailings powder; the particle size of the tailings powder is 400 mesh; (2) mixing the tailing powder in step (1) with NaOH and CH3COONa in a mass ratio of 2:2:2 to obtain a material to be calcined; (3) calcining the material to be calcined in step (2) at a temperature of 900° C. for 6 h, and obtaining a calcined material after the calcination; (4) leaching the roasted material in step (3), wherein the leaching solution is a NaOH solution, the mass ratio of NaOH to the roasted material in the NaOH solution is 1:1, and the liquid-solid ratio is 3 mL:1 g; the leaching temperature is 100° C., the leaching time is 360 min, and when the leaching reaches equilibrium, the solid and liquid are separated to obtain a silicon-containing leachate; (5) subjecting the silicon-containing leachate in step (4) to silicon precipitation, controlling the silicon precipitation pH end point of the silicon-containing leachate to 5; and setting the silicon precipitation temperature to 65° C. to obtain a crude white carbon black product; (6) The crude white carbon black product in step (5) is washed and dried with 20 vol% sulfuric acid solution, anhydrous ethanol and pure water at a drying temperature of 120°C and a drying time of 180 min to obtain a white carbon black product.

[0038] In this comparative example, the silicon dioxide leaching rate is 85.36%, the silicon precipitation rate reaches 88.54%, the product purity is 83.30%, and the BET is 141.5m 2 / g.

Claims

1. A method for extracting white carbon black from shale vanadium extraction tailings, characterized in that: The following steps are involved: (1) crushing and screening the shale vanadium extraction tailings to obtain tailings powder; (2) uniformly mixing the tailings powder with a roasting additive, and then roasting the mixture to obtain a roasting material; the roasting additive includes alkali, CH3COONa and NaF; (3) leaching the roasted material and separating the solid and liquid to obtain a silicon-containing leaching solution; (4) The silicon-containing leaching solution is subjected to silicon precipitation, filtering, washing and drying treatment to obtain white carbon black.

2. The method for extracting white carbon black from shale vanadium extraction tailings according to claim 1, characterized in that: The mass ratio of the tailings powder to the roasting additive is (1-20): (3-41).

3. The method for extracting white carbon black from shale vanadium extraction tailings according to claim 1, characterized in that: The base is NaOH, and the mass ratio of NaOH, CH3COONa and NaF is (1-20): (1-10):

1.

4. The method for extracting white carbon black from shale vanadium extraction tailings according to claim 1, characterized in that: During the calcination process, the calcination temperature is 700-900°C and the calcination time is 2-6h.

5. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: The particle size of the tailings powder is 100-400 meshes.

6. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: When the roasted material is leached, the leaching liquid is a NaOH solution, the mass ratio of NaOH in the NaOH solution to the roasted material is (0-1):1; the liquid-solid ratio of the NaOH solution to the roasted material is (1-20) mL:1 g.

7. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: When the roasted material is leached, the leaching temperature is 25-100° C. and the leaching time is 60-360 minutes.

8. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: During silicon precipitation, the silicon precipitation pH value endpoint of the silicon-containing leaching solution is controlled to be 3-9, and the silicon precipitation temperature is 25-95°C.

9. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: During washing, the washing solution is at least one of sulfuric acid solution, anhydrous ethanol and pure water.

10. The method for extracting white carbon black from shale vanadium extraction tailings according to any one of claims 1 to 4, characterized in that: During the drying process, the drying temperature is 80-250°C and the drying time is 60-480min.