Method for separating and extracting vanadium and chromium from vanadium slag sodium-modified roasting water leachate

Abstract

The invention discloses a method for separating and extracting vanadium and chromium from vanadium slag sodium-modified roasting water leachate. The method comprises the following steps: adding ammonium salt into the vanadium slag sodium modified roasting water leachate, controlling the pH value of the solution system at pH7.5-9.5, stirring to react, and carrying out solid-liquid separation to obtain ammonium metavanadate crystals and filtrate A; extracting an organic phase B and the filtrate A to obtain raffinate A1 and a loaded organic phase B1; subjecting the loaded organic phase B1 to backextraction by adopting a sodium hydroxide solution to obtain strip liquor A2; recycling the raffinate A1; adding a vanadium precipitation agent into the strip liquor A2, carrying out ball milling atroom temperature, and filtering to obtain vanadium-containing filter residues C1 and chromium-containing filtrate A3; adding the raffinate A1 into the vanadium-containing filter residue C1, carrying out ball milling, and filtering to obtain filter residues C2 and vanadium-containing filtrate A4; and calcining the filter residues C2, continuously using the calcined filter residues C2 as a vanadiumprecipitation agent, separating and recovering vanadium in the vanadium-containing filtrate A4 by adopting an ammonium salt vanadium precipitation method, removing impurities from the chromium-containing filtrate A3, and carrying out evaporative crystallization to obtain a sodium chromate product. The method has the advantages that vanadium and chromium can be separated and recycled, and the sodium element and the vanadium and chromium extracted liquid can be recycled.

Description

technical field [0001] The invention belongs to the field of metallurgical separation and circular metallurgy, and in particular relates to a method for separating and extracting vanadium chromium from vanadium slag sodium roasting water leaching solution. Background technique [0002] Vanadium slag is the main industrial raw material for vanadium extraction, and the vanadium slag in my country mainly comes from the pyrometallurgy process of vanadium-titanium magnetite. Vanadium-titanium magnetite is a compound ore in which iron, vanadium, titanium, chromium and other valuable elements coexist. Due to the similar properties of vanadium and chromium, the trend of vanadium and chromium in the pyrometallurgy process is basically the same. The vanadium slag obtained by pyrometallurgy is actually a chromium-containing vanadium slag. Usually, the content of vanadium in slag is much higher than that of chromium, so it is generally called vanadium slag. [0003] The most industrial...

AI Technical Summary

Problems solved by technology

The process is simple, but there are a series of problems: (1) can not handle the solution with high concentration of vanadium and chromium

(2) Chromium cannot be recycled, and a large amount of hazardous solid waste is produced

The treatment of this mother liquor is usually the reduction-neutralization method: firstly, V(V) and Cr(VI) in the solution are reduced, and then neutralized and precipitated to obtain vanadium-chromium reduction slag, which has complex components and can be regenerated It is difficult to use and is a dangerous solid waste

(3) The solution after vanadium precipitation cannot be reused

Although primary ammonium N1923 step-by-step extraction can realize the separation and recovery of vanadium and chromium, the two-step extraction method for separating and extracting vanadium and chromium from the leachate has high cost and no economic applicability, and the separation and extraction of primary ammonium N1923 will produce a large amount of Sodium sulfate raffinate, this raffinate cannot be reused, and the treatment cost is high and difficult

Chinese patent 201711079106.5 first uses the calcium salt precipitation method to selectively and directly precipitate all the vanadium in the vanadium slag sodium roasting water leaching solution, and then uses the carbonate solution to leach the vanadium in the precipitate and recover it. The solution after the vanadium precipitation is electrodialysis- The crystallization method can realize the recovery of chromium and sodium carbonate; but the method is complicated and consumes a lot of alkali

Chinese patent 200610089232.4 discloses a process for extracting and separating vanadium and chromium with primary-secondary amines, using primary-secondary amines to selectively extract vanadium, leaving chromium in the water phase, then recovering chromium by reduction precipitation, and recovering vanadium by ammonium salt precipitation; The method can realize the separation and recovery of vanadium and chromium, but the alkali consumption is large, the waste water cannot be recycled, and the extraction process is difficult to control and the cost of the extraction agent is high.

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