A method for simultaneously extracting vanadium chromium by electrochemically decomposing vanadium slag in a low-temperature low-concentration potassium hydroxide solution

Abstract

The invention relates to a method for synchronously extracting vanadium and chromium during electrochemical resolving of vanadium slag in low-temperature low-concentration potassium hydroxide solution. The method comprises the following steps: (1) batching and heating: mixing and heating vanadium slag and potassium hydroxide solution to prepare mixed slurry; (2) electrolysis: adding the preheated slurry into an electrolysis bath, leading oxidizing gas into the solution, and carrying out electrolysis to obtain reaction slurry; (3) solid-liquid separation: filtering the reaction slurry of the step (2) for separation, so as to obtain tail slag and aqueous alkali containing vanadium and chromium. The method has the advantages that the operation temperature is low; the energy consumption is low; the operation is easy; efficient co-extraction of vanadium and chromium can be realized; the extraction rate of vanadium can be 85 to 99 percent; the extraction rate of chromium can be 80 to 95 percent.

Description

technical field [0001] The invention relates to a method for synchronously extracting vanadium and chromium, in particular to a method for synchronously extracting vanadium and chromium by electrochemically decomposing vanadium slag in a low-temperature low-concentration potassium hydroxide solution. Background technique [0002] Vanadium slag is a general term for vanadium oxide-containing slag obtained from vanadium-containing molten iron through oxidation blowing during the vanadium extraction process or vanadium-containing iron concentrate through wet vanadium extraction. The vanadium slag produced from vanadium-titanium magnetite in the iron and steel industry is the main raw material for vanadium extraction. The composition of vanadium slag is related to the composition of vanadium-titanium magnetite and the production method. Generally speaking, vanadium slag is composed of V 2 o 5 , SiO 2 、Al 2 o 3 , MgO, Cr 2 o 3 、TiO 2 , CaO and other components, and the co...

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Problems solved by technology

[0006] CN102127655A proposes a method for decomposing vanadium slag with NaOH solution under normal pressure. The reaction temperature is 180-260°C. Compared with the roasting process, the temperature of the vanadium extraction process is greatly reduced, the energy consumption is reduced, and the efficiency of vanadium extraction is significantly improved, but it cannot achieve chromium extraction of vanadium and chromium; CN102127654A proposes a method of using sodium hydroxide molten salt to decompose vanadium-chromium-containing slag, the reaction temperature is 500-600°C, this process can realize co-extraction of vanadium and chromium, but the temperature of the molten salt reaction process is relatively high; CN102127656A proposes A method for liquid-phase oxidative decomposition of vanadium slag, through the use of sodium hydroxide and sodium nitrate medium, the process of oxidative decomposition of vanadium slag is strengthened, and the reaction temperature is lower than that of sodium hydroxide molten salt medium, but the sodium nitrate medium is introduced, and the subsequent separation process The steps are increased; CN102531056A proposes a method for the clean production of sodium vanadate and sodium chromate by pressurized leaching of vanadium slag, the reaction temperature is 100-400°C, and the pressure is 0.1-5.0MPa. This method can realize co-extraction of vanadium and chromium, but the reaction temperature is relatively high , and pressurized operation is required; CN101812588A proposes a method for decomposing vanadium slag with potassium hydroxide solution under normal pressure, reacting at 180-260°C, the temperature is greatly reduced, and co-extraction of vanadium and chromium can be realized. The disadvantage is the cost of potassium hydroxide medium Higher; CN102534232A proposes a method for extracting vanadium and chromium by adding carbonaceous substances to a sodium hydroxide solution and decomposing vanadium slag under normal pressure. This method can realize co-extraction of vanadium and chromium, but the extraction rate of chromium is still low (less than 20%)

However, this method uses stainless steel or iron as the anode, and there is a serious problem of anode corrosion, and the reaction medium is an alkaline solution with a concentration of more than 50%, and the medium is still highly corrosive.

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