A kind of vanadium precipitation method of high vanadium high chromium high sodium solution

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a vanadium precipitation method for a high-vanadium, high-chromium and high-sodium solution. The method comprises steps as follows: a, a hydrolysis inhibitor is added to the high-vanadium, high-chromium and high-sodium solution, and the mixture is stirred and heated to 40-80 DEG C; b, pH of the solution is adjusted to range from 3.5 to 7.5, and ammonium salt is added; c, pH of the solution is adjusted to range from 1.5 to 2.5, and the solution is heated to 90 DEG C or higher; d, seed crystals are added, the mixture is kept at the constant temperature until vanadium precipitation is completed and then is left to stand still and filtered, ammonium polyorthovanadate precipitates are obtained and calcined, and V2O5 is obtained. With the adoption of the method, vanadium and chromium in the high-vanadium, high-chromium and high-sodium solution can be effectively separated, sodium and chromium mixed in ammonium vanadate can be greatly reduced, the vanadium precipitation rate is high, the obtained V2O5 product meets quality requirements, produced waste gas is reduced, and the method is high in operability, simple, easy to implement and low in cost.

Description

technical field [0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for depositing vanadium in a high-vanadium, high-chromium, and high-sodium solution. Background technique [0002] The acidic ammonium salt vanadium precipitation process has been widely used at home and abroad because of its advantages such as high vanadium deposition rate and good product quality. But this technique is only applicable to the sodium vanadium solution system that vanadium concentration is lower than 35g / L at present, and for the vanadium solution of high concentration, especially high vanadium high sodium solution, when adopting conventional acidic ammonium salt vanadium precipitation method, due to vanadium and The concentration of sodium is high, it is easy to hydrolyze, and the red cake (xNa 2 O·yV 2 o 5 ·zH 2 O), it is difficult to separate solid and liquid, and the combination speed of sodium and vanadium is fast, it is very ...

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Problems solved by technology

Related reports about high-concentration vanadium precipitation are as follows, patent application "Method for Precipitating Vanadium from High-Nadium and High-Vanadium Solution" (CN105586500A): first preheat the high-sodium and high-vanadium solution, and then mix it with water, vanadium precipitation agent and pH The regulator is mixed with vanadium precipitation, and after vanadium precipitation, the mixed liquid is separated from solid and liquid, the liquid is vanadium precipitation wastewater, the solid is washed and then calcined to obtain vanadium pentoxide; this method uses vanadium precipitation wastewater to dilute the high-sodium and high-vanadium solution In the true sense of high-concentration vanadium precipitation, the number of cycles of vanadium precipitation wastewater needs to be considered during the implementation process; patent application "Method for preparing ammonium polyvanadate from high-concentration vanadium liquid" (CN106006732A): adjust the high-concentration vanadium liquid to a suitable temperature and pH value, add ammonium salt, and then slowly add it into the solution containing vanadium-containing powder material for reaction, and obtain ammonium polyvanadate at the end of the reaction; in this method, high-concentration vanadium liquid is slowly added to the solution containing vanadium-containing powder material Reacting in the medium undoubtedly reduces the concentration of vanadium liquid indirectly, and the whole vanadium precipitation process takes a long time at the same time; Adjust its pH value to 2-3 with acid, keep heating and stirring, slowly add high-concentration vanadium liquid and add acid to maintain pH value 2-3, continue the reaction until the precipitation is complete, then filter to obtain ammonium polyvanadate; this method will It takes a long time to slowly add high-concentration vanadium solution into a certain concentration of ammonium salt solution, and at the same time, a certain concentration of ammonium salt solution increases the water consumption

[0004] In the prior art, the acidic ammonium salt vanadium precipitation process involving high-concentration vanadium liquid is to achieve the purpose of vanadium precipitation by indirectly diluting the concentration of vanadium solution, that is, it needs to increase the amount of water, which is not a real high-concentration vanadium precipitation. None of them involve the influence of chromium in the solution, and there are no relevant research reports on the separation of vanadium and chromium in high-concentration vanadium-chromium solutions based on the precipitation of vanadium.

[0005] For high-vanadium, high-chromium and high-sodium systems, when conventional acidic ammonium salts are used to precipitate vanadium, in addition to being extremely prone to hydrolysis, the presence of high-concentration chromium in the solution will reduce the rate of vanadium precipitation, and at the same time, some Cr will be included in the precipitate. affect product quality

Therefore, for this high-vanadium, high-chromium, and high-sodium solution system, the method of hydrolysis vanadium precipitation-purification is currently used to obtain qualified vanadium products and realize the effective separation of vanadium and chromium, but the yield of vanadium precipitation in the hydrolysis process is low, and the follow-up needs Increase the purification process and increase the amount of wastewater