A method for synchronously extracting vanadium chromium by electrochemically strengthening the decomposition of vanadium slag in sodium hydroxide solution

Abstract

The invention relates to a method for synchronously extracting vanadium and chrome in electrochemical reinforced vanadium slag decomposition of sodium hydroxide solution. The method comprises the following steps: (1) ingredient preheating: vanadium slag and sodium hydroxide water solution are mixed and heated to prepare mixed slurry; (2) electrolysis: the preheated slurry is added in an electrolytic bath; and oxide gas is fed in the solution for electrolyzing to obtain reactive slurry; and (3) solid-liquid separation: the reactive slurry in the step (2) is filtered and separated to obtain tailings and vanadium and chrome-contained aqueous alkali. The method is low in operation temperature, low in energy consumption and simple in operation, and can realize efficient coextraction of the vanadium and the chrome; the extraction rate of the vanadium can reach 85-99%; and the extraction rate of the chrome can reach 80-95%.

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 in a sodium hydroxide solution through electrochemically enhanced decomposition of vanadium slag. 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 composition of vanad...

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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 relatively serious anode corrosion problem, and this method uses potassium hydroxide as the reaction medium, and the cost is relatively high

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