Method for removing and recycling vanadium in alumina seed precipitation mother liquor

Abstract

The invention provides a method for removing and recovering vanadium in alumina seed precipitation mother liquor, which comprises the following steps: mixing the alumina seed precipitation mother liquor, a calcium-containing precipitator and a settling aid, carrying out vanadium precipitation reaction, and carrying out solid-liquid separation to obtain vanadium-containing solid and vanadium-precipitated liquid; wherein the calcium-containing precipitant comprises an activated calcium-based compound; the settling agent comprises polymeric ferric sulfate. The method provided by the invention is high in vanadium removal efficiency, simple in condition and easy to operate, simple in process flow, free from influence on recovery of rare metals, high in high-value resource utilization rate of vanadium and wide in application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, and particularly relates to a method for removing and recovering vanadium in alumina seed mother liquor. BACKGROUND

[0002] Bauxite, as an important potential vanadium resource, contains rich value. The Bayer process, as the mainstream process for extracting alumina from bauxite, occupies a dominant position due to its efficiency and wide applicability. In this process, bauxite undergoes a series of key steps such as dissolution, seed decomposition, and high-temperature roasting, and finally is converted into alumina. However, in the dissolution link, the aluminum in bauxite is converted into sodium aluminate and dissolved into the mother liquor, at the same time, more than 30% of vanadium and part of phosphorus, arsenic, silicon and other impurities in bauxite are also dissolved into the mother liquor, and gradually enriched with the recycling of the mother liquor, which has an adverse effect on the subsequent aluminum hydroxide seed decomposition process, and becomes an important factor restricting the improvement of production efficiency and product quality.

[0003] Currently, in industrial production practice, evaporation cooling crystallization method is generally used to treat vanadium, phosphorus, arsenic, silicon and other impurities in the Bayer process mother liquor. Through the crystallization process, the crystals obtained can be further processed to prepare vanadium slag with V2O5 content of 10%-20%, which is specially called as the crystalline vanadium slag of the Bayer process alumina seed mother liquor in the industry. However, when treating this vanadium slag, the alumina plant usually dissolves it in water and then directly uses ammonium salt to precipitate vanadium to obtain crude ammonium metavanadate. Further calcination treatment can obtain crude V2O5 containing high content of phosphorus, arsenic, silicon, aluminum and other impurities, but the purity of this crude V2O5 is relatively low, which is difficult to meet the demand of high-purity vanadium products. More seriously, the high-salt ammonia-nitrogen wastewater produced in the ammonium salt vanadium precipitation process has a very high treatment cost, which not only further increases the production cost burden of the alumina plant, but also causes serious environmental pollution problems, bringing severe challenges to the sustainable development of enterprises.

[0004] CN119324240A discloses a method for preparing vanadium electrolyte by crystallizing vanadium slag from bayer seed mother liquor, which hydrolyzes VO(OH)2 by adding arsenic removal precipitant to the bayer seed mother liquor crystallized vanadium slag after reduction acid leaching; VO(OH)2 is converted into pentavalent vanadate solution by oxidation alkali leaching, and high-purity vanadate is obtained by further removing impurity ions such as arsenic, phosphorus, aluminum and silicon through crystallization; finally, VOSO4 electrolyte is prepared by hydrolyzing and acid dissolving with sulfuric acid after deep arsenic removal. The method can recover vanadium in the seed mother liquor and prepare vanadium electrolyte, but the recovery process is relatively complex, which needs to go through multiple leaching, hydrolysis and crystallization processes, the production process is long, the equipment requirement is high, the condition requirement is harsh, the production cost is high, a large amount of process wastewater is produced, and the environmental protection treatment cost is high.

[0005] CN102021334A discloses a method for extracting metal gallium and vanadium from bayer seed mother liquor, which adsorbs the bayer seed mother liquor by ion exchange resin, precipitates barium vanadate by adding BaO after washing and desorption, precipitates gallium hydroxide by adding NaOH to the solution after precipitating vanadium, and then dissolves with NaOH solution and electrolyzes to prepare metal gallium. Although the method can separate gallium and vanadium from the seed mother liquor, the preparation system is precise, the equipment requirement is high, the operation process is complex, the purification cost is high, and the process wastewater is much, which does not meet the actual production conditions.

[0006] In recent years, the recovery and purification technology of vanadium resources, and the environment-friendly purification process have been paid more and more attention. The method for removing vanadium from bayer seed mother liquor still needs further research to realize the goals of simplification, diversification and cleanness of vanadium recovery and purification process. SUMMARY

[0007] In view of the deficiencies in the prior art, the purpose of the present application is to provide a method for removing and recovering vanadium in bayer seed mother liquor, which can remove vanadium in bayer seed mother liquor, recover vanadium, and effectively recover rare metal resources, and has a wide application prospect.

[0008] To achieve this purpose, the following technical solutions are adopted in the present application:

[0009] The present application provides a method for removing and recovering vanadium in bayer seed mother liquor, which comprises the following steps: mixing bayer seed mother liquor, calcium-containing precipitant and co-precipitant, carrying out vanadium precipitation reaction, and carrying out solid-liquid separation to obtain vanadium-containing solid and vanadium precipitation solution. The calcium-containing precipitant comprises activated calcium-based compound. The co-precipitant comprises polyferric sulfate.

[0010] The alumina seed mother liquor containing vanadium also contains impurities such as phosphorus, arsenic, silicon and aluminum, and the presence of these impurities makes it difficult to meet the preparation of high-purity vanadium products, and the treatment cost of high-salt ammonia-nitrogen wastewater generated in the traditional ammonium salt vanadium precipitation process is extremely high. The pre-removal method of vanadium from the alumina seed mother liquor provided by the present application uses activated calcium-based compounds as a precipitant and polymeric ferric sulfate as a co-precipitant, which can promote the precipitation of calcium vanadate and improve the precipitation rate of vanadium. Specifically, Fe 3+ Fe(OH)3colloid is quickly generated in an alkaline solution, and the Fe(OH)3colloid uses the surface charge adsorption to aggregate and flocculate the tiny calcium vanadate precipitate particles, thereby accelerating the precipitation of calcium vanadate and improving the precipitation rate of vanadium.

[0011] Furthermore, the present application uses activated calcium-based compounds, and high-activity calcium oxide is crucial for the reaction to generate calcium vanadate, especially in an alkaline system. This is because ordinary calcium oxide will react with CO2 in the air to form a CaCO3solid product layer after long-term placement in the air, and the solid product layer will hinder the reaction of CaO with water to generate soluble Ca(OH)2in an alkaline solution, thereby hindering the precipitation of calcium vanadate. High-temperature activation can completely decompose CaCO3and release high-activity sites, which is beneficial to the reaction of CaO with water.

[0012] Preferably, the calcium-based compound includes any one or a combination of at least two of calcium carbonate, calcium hydroxide, calcium oxide or calcium chloride, and a typical but non-limiting combination is a combination of calcium carbonate and calcium hydroxide, a combination of calcium oxide and calcium hydroxide, a combination of calcium carbonate and calcium oxide, a combination of calcium chloride and calcium hydroxide.

[0013] Preferably, the activation of the calcium-containing precipitant includes high-temperature activation treatment of the calcium-based compound.

[0014] Preferably, the temperature of the high-temperature activation treatment is 850-1000℃, for example, it can be 850℃, 870℃, 890℃, 900℃, 920℃, 940℃, 960℃, 980℃ or 1000℃, but is not limited to the listed values, and other unlisted values in this range are also applicable.

[0015] The present application preferably controls the temperature of the high-temperature activation treatment in the above range, which can further improve the precipitation effect of the precipitant.

[0016] Preferably, the high-temperature activation treatment time is 1 to 2 hours, for example, it can be 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2.0h, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, the alumina seed mother liquor includes sodium, aluminum, and gallium.

[0018] In the alumina seed mother liquor of this invention, sodium generally exists in the form of sodium ions, and aluminum generally exists as AlO2. - Gallium exists in the form of GaO2. - It exists in the form of.

[0019] Preferably, the concentration of sodium element in the alumina seed mother liquor, calculated as Na2O, is 100~200 g / L, for example, it can be 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, 160 g / L, 170 g / L, 180 g / L, 190 g / L or 200 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0020] Preferably, the concentration of aluminum element in the alumina seed mother liquor, calculated as Al2O3, is 50~100g / L, for example, it can be 50g / L, 55g / L, 60g / L, 65g / L, 70g / L, 75g / L, 80g / L, 85g / L, 90g / L, 95g / L or 100g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] Preferably, the concentration of gallium element in the alumina seed mother liquor, calculated as Ga2O3, is 100~300 mg / L, for example, it can be 100 mg / L, 120 mg / L, 140 mg / L, 160 mg / L, 180 mg / L, 200 mg / L, 220 mg / L, 240 mg / L, 260 mg / L, 280 mg / L or 300 mg / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0022] Preferably, the alumina seed mother liquor further includes any one or a combination of at least two of V, Si, or Fe, wherein typical but non-limiting combinations are combinations of V and Si, combinations of Fe and Si, combinations of V and Fe, and combinations of Fe, V, and Si.

[0023] In the alumina seed mother liquor of the present invention, V exists in the form of metavanadate and Si exists in the form of metasilicate.

[0024] Preferably, the concentration of V in the alumina seed mother liquor is 100~300 mg / L, for example, it can be 100 mg / L, 120 mg / L, 140 mg / L, 160 mg / L, 180 mg / L, 200 mg / L, 220 mg / L, 240 mg / L, 260 mg / L, 280 mg / L or 300 mg / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0025] Preferably, the concentration of Si in the alumina seed mother liquor is 0.05~5 g / L, for example, it can be 0.05 g / L, 0.50 g / L, 1.00 g / L, 1.50 g / L, 2.00 g / L, 2.50 g / L, 3.00 g / L, 3.50 g / L, 4.00 g / L, 4.50 g / L or 5.00 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the Fe concentration in the alumina seed mother liquor is 0.1~1 g / L, for example, it can be 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, or 1.0 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the settling aid is added in the form of a settling aid solution.

[0028] Preferably, the concentration of the flocculant in the flocculant solution is 100~150 g / L, for example, it can be 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L, 135 g / L, 140 g / L, 145 g / L or 150 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] The present invention preferably controls the concentration of the flocculant in the flocculant solution within the above-mentioned range, which can significantly improve the vanadium recovery rate and the purity of vanadium in the purified solution.

[0030] Preferably, the amount of the flocculant solution added is 0.1 to 0.3% of the volume of the alumina seed mother liquor, for example, it can be 0.10%, 0.12%, 0.14%, 0.16%, 0.18%, 0.20%, 0.22%, 0.24%, 0.26%, 0.28%, or 0.30%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] The present invention preferably controls the amount of flocculant solution added within the above-mentioned range, which can significantly improve the precipitation effect of vanadium, thereby ensuring the removal effect of vanadium; and can also avoid the problems caused by excessive flocculant.

[0032] Preferably, the amount of calcium-containing precipitant added is 1.2 to 1.5 times the molar amount of vanadium in the alumina seed mother liquor, for example, it can be 1.20 times, 1.25 times, 1.30 times, 1.30 times, 1.35 times, 1.40 times, 1.45 times or 1.50 times, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] The present invention preferably controls the amount of calcium-containing precipitant added within the above-mentioned range, which can better improve the precipitation rate of vanadium and improve the purity of vanadium.

[0034] Preferably, the temperature of the vanadium precipitation reaction is 80~90℃, for example, it can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃ or 90℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the vanadium precipitation reaction time is 1 to 3 hours, for example, it can be 1.0 hours, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3.0 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the stirrer for the vanadium precipitation reaction is a disc turbine propeller.

[0037] Preferably, the shear force of the disc turbine propeller is 15~35kPa, for example, it can be 15kPa, 17kPa, 19kPa, 21kPa, 23kPa, 25kPa, 27kPa, 29kPa, 31kPa, 33kPa or 35kPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the stirring rate of the vanadium precipitation reaction is 500~900 r / min, for example, it can be 500 r / min, 540 r / min, 580 r / min, 620 r / min, 660 r / min, 700 r / min, 740 r / min, 780 r / min, 820 r / min, 860 r / min or 900 r / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Activated calcium oxide reacts with calcium hydroxide in solution, but calcium hydroxide has very low solubility. As soluble calcium ions continuously participate in the reaction to form calcium vanadate, new calcium hydroxide dissolves into the liquid phase. However, the formation of calcium vanadate encapsulates undissolved calcium hydroxide solids, hindering further dissolution of calcium ions. Strong shear force and high-speed stirring can significantly reduce the formation of the calcium vanadate solid product layer, allowing calcium ions to diffuse continuously into the solution unaffected by the product layer and react with vanadate ions. Therefore, these two factors are crucial for improving the precipitation rate of vanadium and the utilization rate of calcium ions.

[0040] Preferably, the removal and recovery method includes: mixing the vanadium-precipitated liquid and a flocculant for flocculation and precipitation, followed by solid-liquid separation to obtain impurity sludge and purified liquid.

[0041] This invention further removes impurities by flocculating and precipitating the vanadium-precipitated liquid, thereby obtaining a purified liquid with a high gallium content, which has broad application prospects.

[0042] Preferably, the flocculant comprises any one or a combination of at least two of polyethylene glycol, polyacrylamide, or sodium polyacrylate, wherein typical but non-limiting combinations are combinations of polyethylene glycol and polyacrylamide, combinations of sodium polyacrylate and polyacrylamide, and combinations of polyethylene glycol and sodium polyacrylate.

[0043] Preferably, the flocculant is added in the form of a flocculant solution.

[0044] Preferably, the concentration of flocculant in the flocculant solution is 1~3 g / L, for example, it can be 1.0 g / L, 1.2 g / L, 1.4 g / L, 1.6 g / L, 1.8 g / L, 2.0 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L or 3.0 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the flocculant solution accounts for 5-10% of the volume of the liquid after vanadium precipitation, for example, it can be 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5% or 10.0%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0046] Preferably, the flocculation and sedimentation time is 2 to 10 minutes, for example, it can be 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] Preferably, the flocculation and sedimentation temperature is 40~60℃, for example, it can be 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃ or 60℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] In this invention, the slurry after flocculation and sedimentation is filtered to obtain purified liquid and impurity sludge. Preferred filtration methods include plate and frame filter press and vacuum belt filter.

[0049] As a preferred technical solution of the present invention, the removal and recovery method includes:

[0050] (1) Calcium-based compounds are activated at 850~1000℃ for 1~2h to obtain calcium-containing precipitants.

[0051] (2) Mix alumina seed mother liquor, calcium-containing precipitant and polyferric sulfate solution with a concentration of 100~150g / L. The amount of precipitant solution added is 0.1~0.3% of the volume of alumina seed mother liquor, and the amount of calcium-containing precipitant added is 1.2-1.5 times the molar amount of vanadium in alumina seed mother liquor. Under the conditions of stirring speed of 500~900r / min with a disc turbine impeller with a shear force of 15~35kPa and temperature of 80~90℃, vanadium precipitation reaction is carried out for 1~3h. After solid-liquid separation, vanadium-containing solid and vanadium-precipitated liquid are obtained.

[0052] (3) Mix the vanadium-precipitated liquid with a flocculant solution of 1~3g / L, the flocculant solution accounting for 5~10% of the volume of the vanadium-precipitated liquid, and flocculate and precipitate at a temperature of 40~60℃ for 2~10min, and then separate the solid and liquid to obtain impurity mud and purified liquid; wherein the flocculant includes any one or a combination of at least two of polyethylene glycol, polyacrylamide or sodium polyacrylate.

[0053] The present invention does not impose any special restrictions on the solid-liquid separation in the above process. Any device and method known to those skilled in the art for solid-liquid separation can be used. It can also be adjusted according to the actual process. For example, it can be filtration, centrifugation or sedimentation separation, or a combination of different methods.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] (1) The method for removing and recovering vanadium from alumina seed mother liquor provided by the present invention selects a suitable precipitant activated at high temperature to remove vanadium from alumina seed mother liquor with obvious selectivity, so as not to affect the precipitation of other high-value metals, effectively separate different elements, reduce the loss of other resources, the removal process is simple and efficient, and the requirements for the content of impurity elements are not high; specifically, under preferred conditions, the concentration of V in the purified liquid can be controlled within 55 mg / L, the concentration of Si in the purified liquid can be controlled within 180 mg / L, and the gallium entrainment in the vanadium-containing solid is within 0.14%, the gallium loss is low, and the purity of the obtained vanadium-containing solid is above 90%;

[0056] (2) The method for removing and recovering vanadium from alumina seed mother liquor provided by the present invention utilizes the characteristics of high-temperature activation to rapidly increase the removal efficiency of precipitant, give full play to the role of precipitant, and make the vanadium recovery rate in alumina seed mother liquor high, clean and environmentally friendly, and can realize industrial production.

[0057] (3) The method for removing and recovering vanadium from the mother liquor of alumina seed solution provided by the present invention can efficiently remove other impurity elements in the mother liquor of alumina seed solution through a simple subsequent flocculation and precipitation method. The purified liquid produced can be returned to the alumina preparation production line, which can achieve high-value comprehensive utilization of resources and greatly reduce the loss of alumina production costs. Attached Figure Description

[0058] Figure 1 This is a schematic flowchart of a method for removing and recovering vanadium from alumina seed mother liquor provided in a specific embodiment of the present invention. Detailed Implementation

[0059] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0060] In this invention, gallium is typically recovered by adsorbing it onto resin in the alumina seed mother liquor. However, during gallium recovery, the presence of vanadium (V) affects the resin adsorption process, and the presence of silicon (Si) also affects the resin's adsorption lifespan. The vanadium removal method provided in this invention significantly reduces the vanadium concentration, thereby facilitating subsequent resin adsorption and recovery of gallium from the alumina seed mother liquor. Therefore, it is essential to minimize gallium precipitation during vanadium removal to reduce gallium loss. This will be explained in detail below.

[0061] As a specific embodiment of the present invention, a method for removing and recovering vanadium from alumina seed mother liquor is provided, the process flow diagram of which is shown below. Figure 1 As shown, the removal and recovery method includes:

[0062] (1) Calcium-based compounds are activated at high temperature to obtain calcium-containing precipitants.

[0063] (2) Mix the mother liquor of alumina, calcium-containing precipitant and polyferric sulfate solution (i.e. precipitant) to carry out vanadium precipitation reaction, and then separate the solid and liquid (e.g., by filtration) to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0064] (3) Mix the vanadium-precipitated liquid and the flocculant solution, and carry out flocculation and precipitation, and then separate the solid and liquid (e.g., by filtration) to obtain impurity mud and purified liquid.

[0065] Example 1

[0066] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0067] (1) Calcium-based compounds (calcium carbonate) were activated at 950°C for 1 hour to obtain calcium-containing precipitants.

[0068] (2) A mixture of alumina seed mother liquor (sodium concentration of 150 g / L as Na2O, aluminum concentration of 70 g / L as Al2O3, gallium concentration of 200 mg / L as Ga2O3, V concentration of 200 mg / L, Si concentration of 3 g / L, and Fe concentration of 0.3 g / L), calcium precipitant, and polyferric sulfate solution with a concentration of 130 g / L was prepared. The amount of polyferric sulfate solution added was 0.2% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.3 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 2 h under the conditions of stirring at 700 r / min with a disc turbine impeller with a shear force of 23 kPa and a temperature of 90 °C. The mixture was then filtered by plate and frame press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0069] (3) Mix the vanadium-precipitated liquid with a polyethylene glycol solution of 2 g / L (polyethylene glycol has a weight-average molecular weight of 4000), and the flocculant solution accounts for 7% of the volume of the vanadium-precipitated liquid. Flocculation and precipitation are carried out at a temperature of 53℃ for 6 min, and then filtered to obtain impurity mud and purified liquid.

[0070] Example 2

[0071] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0072] (1) Calcium-based compound (calcium hydroxide) was activated at 1000℃ for 1 hour to obtain a calcium-containing precipitant.

[0073] (2) A mixture of alumina seed mother liquor (sodium concentration of 110 g / L as Na2O, aluminum concentration of 60 g / L as Al2O3, gallium concentration of 280 mg / L as Ga2O3, V concentration of 120 mg / L, Si concentration of 1 g / L, and Fe concentration of 0.1 g / L), calcium precipitant, and 110 g / L polyferric sulfate solution was prepared. The amount of polyferric sulfate solution added was 0.1% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.4 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 1 h under the conditions of stirring at 600 r / min with a disc turbine impeller with a shear force of 28 kPa and a temperature of 80 °C. The mixture was then filtered by plate and frame press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0074] (3) Mix the vanadium-precipitated liquid with a 1 g / L polyacrylamide solution (the weight-average molecular weight of polyacrylamide is 10 million), the flocculant solution accounts for 6% of the volume of the vanadium-precipitated liquid, and flocculate and precipitate at a temperature of 50℃ for 4 min, and then filter to obtain impurity mud and purified liquid.

[0075] Example 3

[0076] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0077] (1) Calcium-based compounds (calcium oxide) were activated at 950°C for 3 hours to obtain calcium-containing precipitants.

[0078] (2) A mixture of alumina seed mother liquor (sodium concentration of 180 g / L as Na2O, aluminum concentration of 90 g / L as Al2O3, gallium concentration of 120 mg / L as Ga2O3, V concentration of 280 mg / L, Si concentration of 4 g / L, and Fe concentration of 0.4 g / L), calcium precipitant, and polyferric sulfate solution with a concentration of 140 g / L was prepared. The amount of polyferric sulfate solution added was 0.15% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.4 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 3 h under the conditions of stirring at 800 r / min with a disc turbine impeller with a shear force of 24 kPa and a temperature of 90 °C. The mixture was then filtered by plate and frame filter press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0079] (3) Mix the vanadium-precipitated liquid with a sodium polyacrylate solution of 3 g / L (sodium polyacrylate has a weight-average molecular weight of 10 million), and the flocculant solution accounts for 8% of the volume of the vanadium-precipitated liquid. Flocculation and precipitation are carried out at a temperature of 55℃ for 8 min, and then filtered to obtain impurity mud and purified liquid.

[0080] Example 4

[0081] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0082] (1) Calcium-based compound (calcium chloride) was activated at 1000℃ for 2 hours to obtain a calcium-containing precipitant.

[0083] (2) A mixture of alumina seed mother liquor (sodium concentration of 120 g / L as Na2O, aluminum concentration of 90 g / L as Al2O3, gallium concentration of 300 mg / L as Ga2O3, V concentration of 280 mg / L, Si concentration of 5 g / L, and Fe concentration of 0.5 g / L), calcium precipitant, and polyferric sulfate solution with a concentration of 150 g / L was prepared. The amount of polyferric sulfate solution added was 0.3% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.5 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 1 h under the conditions of stirring at 500 r / min with a disc turbine impeller with a shear force of 28 kPa and a temperature of 80 °C. The mixture was then filtered by plate and frame press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0084] (3) Mix the vanadium-precipitated liquid with a 1 g / L polyacrylamide solution (the weight average molecular weight of polyacrylamide is 20 million), and the flocculant solution accounts for 10% of the volume of the vanadium-precipitated liquid. Flocculate and precipitate at a temperature of 45℃ for 10 min, and then filter to obtain impurity mud and purified liquid.

[0085] Example 5

[0086] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0087] (1) Calcium-based compound (calcium hydroxide) was activated at 850°C for 1 hour to obtain a calcium-containing precipitant.

[0088] (2) Mixed alumina seed mother liquor (sodium concentration of Na2O is 100 g / L, aluminum concentration of Al2O3 is 50 g / L, gallium concentration of Ga2O3 is 100 mg / L, V concentration is 100 mg / L, Si concentration is 0.05 g / L, Fe concentration is 0.5 g / L), calcium precipitant and polyferric sulfate solution with a concentration of 100 g / L, the amount of polyferric sulfate solution added is 0.1% of the volume of alumina seed mother liquor, the amount of calcium precipitant added is 1.2 times the molar amount of vanadium in alumina seed mother liquor, vanadium precipitation reaction is carried out for 1 h under the conditions of stirring speed of 900 r / min of disc turbine impeller with shear force of 20 kPa and temperature of 80℃, and then filtered by plate and frame filter press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0089] (3) Mix the vanadium-precipitated liquid with a 3 g / L polyacrylamide solution (the weight-average molecular weight of polyacrylamide is 15 million), and the flocculant solution accounts for 5% of the volume of the vanadium-precipitated liquid. Flocculation and precipitation are carried out at a temperature of 50℃ for 2 min, and then filtered to obtain impurity mud and purified liquid.

[0090] Example 6

[0091] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0092] (1) Calcium-based compound (calcium hydroxide) was activated at 850°C for 2 hours to obtain a calcium-containing precipitant.

[0093] (2) A mixture of alumina seed mother liquor (sodium concentration of 180 g / L as Na2O, aluminum concentration of 60 g / L as Al2O3, gallium concentration of 100 mg / L as Ga2O3, V concentration of 300 mg / L, Si concentration of 5 g / L, and Fe concentration of 0.6 g / L), calcium precipitant, and 100 g / L polyferric sulfate solution was prepared. The amount of polyferric sulfate solution added was 0.1% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.3 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 1 h under the conditions of stirring at 900 r / min with a disc turbine impeller at a shear force of 25 kPa and a temperature of 80 °C. The mixture was then filtered by plate and frame press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0094] (3) Mix the vanadium-precipitated liquid with a 1 g / L polyacrylamide solution (the weight-average molecular weight of polyacrylamide is 10 million), and the flocculant solution accounts for 10% of the volume of the vanadium-precipitated liquid. Flocculate and precipitate at a temperature of 55℃ for 8 min, and then filter to obtain impurity mud and purified liquid.

[0095] Example 7

[0096] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor, the method comprising the following steps:

[0097] (1) Calcium-based compound (calcium hydroxide) was activated at 900℃ for 2 hours to obtain a calcium-containing precipitant.

[0098] (2) A mixture of alumina seed mother liquor (sodium concentration of 160 g / L as Na2O, aluminum concentration of 80 g / L as Al2O3, gallium concentration of 180 mg / L as Ga2O3, V concentration of 280 mg / L, Si concentration of 4.8 g / L, and Fe concentration of 0.48 g / L), calcium precipitant, and polyferric sulfate solution with a concentration of 148 g / L was prepared. The amount of polyferric sulfate solution added was 0.28% of the volume of alumina seed mother liquor, and the amount of calcium precipitant added was 1.4 times the molar amount of vanadium in the alumina seed mother liquor. The vanadium precipitation reaction was carried out for 2.5 h under the conditions of stirring at 880 r / min with a disc turbine impeller with a shear force of 30 kPa and a temperature of 88 °C. The mixture was then filtered by plate and frame press to obtain vanadium-containing solid and vanadium-precipitated liquid.

[0099] (3) Mix the vanadium-precipitated liquid with a polyethylene glycol solution of 2.8 g / L (the weight average molecular weight of polyethylene glycol is 2000), and the flocculant solution accounts for 8% of the volume of the vanadium-precipitated liquid. Flocculation and precipitation are carried out at a temperature of 52℃ for 8 min, and then filtered to obtain impurity mud and purified liquid.

[0100] Example 8

[0101] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the addition amount of polyferric sulfate solution, which is 0.05% of the volume of alumina seed mother liquor, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0102] Example 9

[0103] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the addition amount of polyferric sulfate solution, which is 0.4% of the volume of alumina seed mother liquor, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0104] Example 10

[0105] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the addition of calcium precipitant at a rate of 1.0 times the molar amount of vanadium in the alumina seed mother liquor, the removal and recovery method is the same as in Example 1 and will not be repeated here.

[0106] Example 11

[0107] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the amount of calcium precipitant added being 1.6 times the molar amount of vanadium in the alumina seed mother liquor, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0108] Example 12

[0109] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the stirring speed of the vanadium precipitation reaction being 400 r / min, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0110] Example 13

[0111] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the stirring speed of 1000 r / min in the vanadium precipitation reaction, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0112] Example 14

[0113] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the fact that the flocculant solution accounts for 3% of the volume of the liquid after vanadium precipitation, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0114] Example 15

[0115] This embodiment provides a method for removing and recovering vanadium from alumina seed mother liquor. Except for the fact that the flocculant solution accounts for 15% of the volume of the liquid after vanadium precipitation, the removal and recovery method is the same as in Example 1, and will not be repeated here.

[0116] Comparative Example 1

[0117] This comparative example provides a method for treating alumina seed mother liquor. The method is the same as in Example 3 except that no flocculant is added, and will not be described again here.

[0118] Comparative Example 2

[0119] This comparative example provides a method for treating alumina seed mother liquor. The method is the same as in Example 3 except that no precipitant is added, and will not be described again here.

[0120] Comparative Example 3

[0121] This comparative example provides a method for treating alumina seed mother liquor. The removal and recovery method is the same as in Example 6, except that calcium carbonate is added directly without high-temperature activation treatment, and will not be described again here.

[0122] Comparative Example 4

[0123] This comparative example provides a method for treating alumina seed mother liquor. The removal and recovery method is the same as in Example 1, except that the polyferric sulfate solution is replaced with polyaluminum sulfate solution, and will not be described again here.

[0124] Test methods: The concentrations of V, Ga, Al, and Si in the purified liquid were determined by ICP-OES (inductively coupled plasma optical emission spectrometry), and the purity of vanadium and the amount of gallium entrained in the vanadium-containing solid were determined by XRF (X-ray fluorescence spectrometry).

[0125] The test results of the above embodiments and comparative examples are shown in Table 1.

[0126] Table 1

[0127]

[0128] The following points can be observed from Table 1:

[0129] (1) As can be seen from Examples 1 to 7, the method for removing and recovering vanadium from alumina seed mother liquor provided by the present invention can achieve the removal and recovery of vanadium from alumina seed mother liquor. The concentration of V in the purified liquid can be controlled within 55 mg / L, the concentration of Si in the purified liquid can be controlled within 180 mg / L, and the amount of gallium entrained in the vanadium-containing solid is within 0.14%, the gallium loss is low, and the purity of the obtained vanadium-containing solid is above 90%.

[0130] (2) As can be seen from Examples 1 and 8-9, in Example 8, due to insufficient addition of flocculant, V in the solution could not completely precipitate in solid form after reacting with the calcium-containing precipitant. Therefore, some V would still remain in the vanadium-precipitated solution, resulting in incomplete vanadium removal. In Example 9, due to excessive addition of flocculant, too much flocculant remained in the solution, leading to waste of auxiliary materials. Furthermore, the excessive flocculant would preferentially react with the flocculant added during the flocculation and sedimentation process, ultimately affecting the impurity removal effect in the purified solution. This indicates that the present invention preferably controls the addition of flocculant within a reasonable range, which can better improve the vanadium removal effect in the alumina seed mother liquor.

[0131] (3) As can be seen from Examples 1 and 10-11, the addition of calcium-containing precipitant in Example 10 was insufficient, resulting in vanadium in the alumina seed mother liquor not fully participating in the reaction and precipitating out in solid form, ultimately leading to incomplete vanadium removal. In Example 11, the addition of excessive calcium-containing precipitant caused excess calcium-containing precipitant that did not participate in the vanadium precipitation reaction to preferentially react with the precipitant aid. Due to the insufficient precipitant aid, the vanadium-containing solid produced by the vanadium precipitation reaction could not precipitate out in a timely manner, ultimately resulting in incomplete vanadium removal. This indicates that by controlling the amount of calcium-containing precipitant added within a reasonable range, the present invention can better improve the vanadium removal effect.

[0132] (4) It can be seen from the combined examples 1 and 12-13 that in example 12, the vanadium-containing solid produced by the vanadium precipitation reaction first exists in the solution in the form of agglomerates. Due to the low stirring rate, the agglomerates cannot be broken up, resulting in some gallium being encapsulated. At the same time, the encapsulated vanadium cannot fully react with the calcium-containing precipitant, which ultimately leads to incomplete vanadium removal. In example 13, the stirring rate is too fast, which causes the added calcium-containing precipitant to be broken up before it has a chance to react with the vanadium in the solution, resulting in insufficient time for the vanadium precipitation reaction and ultimately affecting the vanadium removal effect in the solution. This shows that the present invention can further improve the vanadium removal effect by controlling the stirring rate within a reasonable range.

[0133] (5) It can be seen from the combined examples 1 and 14-15 that the amount of flocculant added in example 14 is too low, which will result in the flocculant not being completely flocculated and settled in the solution, resulting in insufficient impurity removal effect and affecting the purity of the purified solution; the amount of flocculant added in example 15 is too high, and the excess flocculant that does not participate in the flocculation and sedimentation reaction will exist in the solution, which will affect the purity of gallium products prepared from the purified solution. This shows that the present invention controls the amount of flocculant added within a reasonable range, which can further improve the vanadium removal effect.

[0134] (6) No flocculant or precipitant was added in Comparative Examples 1 and 2, and the vanadium removal effect was not good. In Comparative Example 3, calcium carbonate was added directly without high-temperature activation treatment, and the vanadium removal effect was significantly reduced compared with Example 6. In Comparative Example 4, polyferric sulfate solution was replaced with polyaluminum sulfate solution. The results showed that the addition of polyferric sulfate could precipitate a very small portion of V in the solution that had not undergone the vanadium precipitation reaction as ferric vanadate and vanadium-containing solid at the same time. However, after adding polyaluminum sulfate, due to the high reaction conditions, it could not react with V in the solution, resulting in a poor vanadium removal effect.

[0135] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for removing and recovering vanadium from alumina seed mother liquor, characterized in that, The removal and recovery method includes the following steps: Mixed alumina mother liquor, calcium-containing precipitant and precipitant are used to carry out vanadium precipitation reaction, and after solid-liquid separation, vanadium-containing solid and vanadium-precipitated liquid are obtained; The calcium-containing precipitant includes an activated calcium-based compound; the precipitant aid includes polyferric sulfate.

2. The removal and recovery method according to claim 1, characterized in that, The calcium-based compound includes any one or a combination of at least two of calcium carbonate, calcium hydroxide, calcium oxide, or calcium chloride.

3. The removal and recovery method according to claim 1 or 2, characterized in that, The activation of the calcium-containing precipitant includes: subjecting the calcium-based compound to high-temperature activation treatment; Preferably, the temperature of the high-temperature activation treatment is 850~1000℃; Preferably, the high-temperature activation treatment takes 1 to 2 hours.

4. The removal and recovery method according to any one of claims 1 to 3, characterized in that, The alumina seed mother liquor includes sodium, aluminum, and gallium. Preferably, the concentration of sodium element in the alumina seed mother liquor, calculated as Na2O, is 100~200 g / L; Preferably, the concentration of aluminum element in the alumina seed mother liquor, calculated as Al2O3, is 50~100g / L; Preferably, the concentration of gallium element in the alumina seed mother liquor, calculated as Ga2O3, is 100~300 mg / L; Preferably, the alumina seed mother liquor further includes any one or a combination of at least two of V, Si, or Fe; Preferably, the concentration of V in the alumina seed mother liquor is 100~300 mg / L; Preferably, the concentration of Si in the alumina seed mother liquor is 0.05~5 g / L; Preferably, the concentration of Fe in the alumina seed mother liquor is 0.1~1g / L.

5. The removal and recovery method according to any one of claims 1 to 4, characterized in that, The settling aid is added in the form of a settling aid solution; Preferably, the concentration of the flocculant in the flocculant solution is 100~150g / L; Preferably, the amount of the flocculant solution added is 0.1 to 0.3% of the volume of the alumina seed mother liquor.

6. The removal and recovery method according to any one of claims 1 to 5, characterized in that, The amount of calcium-containing precipitant added is 1.2 to 1.5 times the molar amount of vanadium in the alumina seed mother liquor.

7. The removal and recovery method according to any one of claims 1 to 6, characterized in that, The temperature for the vanadium precipitation reaction is 80~90℃; Preferably, the vanadium precipitation reaction takes 1 to 3 hours.

8. The removal and recovery method according to any one of claims 1 to 7, characterized in that, The stirrer for the vanadium precipitation reaction is a disc turbine propeller; Preferably, the shear force of the disc turbine propeller is 15~35kPa; Preferably, the stirring rate of the vanadium precipitation reaction is 500~900 r / min.

9. The removal and recovery method according to any one of claims 1 to 8, characterized in that, The removal and recovery method includes: mixing the vanadium-precipitated liquid and flocculant for flocculation and precipitation, followed by solid-liquid separation to obtain impurity sludge and purified liquid; Preferably, the flocculant comprises any one or a combination of at least two of polyethylene glycol, polyacrylamide, or sodium polyacrylate; Preferably, the flocculant is added in the form of a flocculant solution; Preferably, the concentration of flocculant in the flocculant solution is 1~3 g / L; Preferably, the flocculant solution accounts for 5-10% of the volume of the liquid after vanadium precipitation; Preferably, the flocculation and sedimentation time is 2-10 minutes; Preferably, the temperature for flocculation and sedimentation is 40~60℃.

10. The removal and recovery method according to any one of claims 1 to 9, characterized in that, The removal and recovery method includes: (1) Calcium-based compounds are activated at 850~1000℃ for 1~2h to obtain calcium-containing precipitants; (2) Mix alumina seed mother liquor, calcium-containing precipitant and polyferric sulfate solution with a concentration of 100~150g / L. The amount of precipitant solution added is 0.1~0.3% of the volume of alumina seed mother liquor, and the amount of calcium-containing precipitant added is 1.2~1.5 times the molar amount of vanadium in alumina seed mother liquor. Under the conditions of stirring speed of 500~900r / min with a disc turbine impeller with a shear force of 15~35kPa and temperature of 80~90℃, vanadium precipitation reaction is carried out for 1~3h. After solid-liquid separation, vanadium-containing solid and vanadium-precipitated liquid are obtained. (3) Mix the vanadium-precipitated liquid with a flocculant solution of 1~3g / L, the flocculant solution accounting for 5~10% of the volume of the vanadium-precipitated liquid, and flocculate and precipitate at a temperature of 40~60℃ for 2~10min, and then separate the solid and liquid to obtain impurity mud and purified liquid; wherein the flocculant includes any one or a combination of at least two of polyethylene glycol, polyacrylamide or sodium polyacrylate.

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