Method for synchronously extracting vanadium and chromium by electrochemically decomposing vanadium slag in potassium hydroxide solution

Abstract

The invention relates to a method for synchronously extracting vanadium and chromium by electrochemically decomposing vanadium slag in a potassium hydroxide solution. The method comprises the steps as follows: introducing oxidizing gas into mixed slurry containing the vanadium slag, potassium hydroxide and water; carrying out electrochemical oxidization reaction; and after the reaction, carrying out solid-liquid separation on the mixed slurry to obtain tailings and a vanadium and chromium alkali solution. The method is low in cost, high in extraction efficiency, pollution-free and moderate in process conditions, and can be used for efficiently and synchronously extracting vanadium and chromium; the vanadium extraction rate can reach 85-99%; and the chromium extraction rate can reach 80-95%.

Description

technical field [0001] The invention relates to a method for synchronously extracting vanadium chromium by electrochemically decomposing vanadium slag, in particular to a method for synchronously extracting vanadium chromium by electrochemically decomposing vanadium slag in a potassium hydroxide solution. Background technique [0002] Vanadium slag is a vanadium-enriched material produced by blowing vanadium-containing molten iron in the presence of oxygen-containing gas. In the iron and steel industry, vanadium slag produced from vanadium-titanium magnetite is the main raw material for extracting vanadium. 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 vanadium slag in each factory is also very different, but its phase structure is basically the sa...

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Problems solved by technology

[0005] CN1884597A, CN86108218A, CN102477491A, CN102242274A etc. have carried out different improvements to factors such as additives and temperature control of sodium roasting process, and basic principle is all by using the additive (Na 2 CO 3 , NaCl, Na 2 SO 4 、Na 2 SO 3 etc.) and different temperature systems to improve and increase the extraction rate of vanadium, roasting time, furnace charge sintering and other indicators, but the above process is basically the same as the traditional sodium roasting principle, operation process, and operating temperature, and it is impossible to avoid excessive roasting temperature, etc. Problems with Traditional Crafts

[0007] 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 be achieved Extraction of 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 is proposed. By using 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. However, sodium nitrate medium is introduced, and subsequent separation Process steps increase; CN102531056A proposes a method for vanadium slag pressurized leaching to cleanly produce sodium vanadate sodium chromate, reaction temperature 100-400 ℃, pressure 0.1-5.0MPa, this method can realize vanadium chromium is extracted together, but reaction temperature is higher 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. However, this method requires high temperature and high Concentration KOH solution is the reaction medium, which has high requirements on equipment materials; CN102534232A proposes a method for extracting vanadium and chromium by adding carbonaceous substances to the solution of sodium hydroxide and decomposing vanadium slag under normal pressure to extract vanadium and chromium. Still low (less than 20%)

This method avoids the problems of high energy consumption and high pollution in the traditional leaching method, and it has wide application, good selectivity, mild process conditions and no pollution, but the leaching efficiency of this method is low

[0009] CN102534229A proposes a method for selectively leaching vanadium from converter vanadium slag, mixing powdery converter vanadium slag with sulfuric acid, tributyl phosphate and sulfonated kerosene to prepare ore slurry, and placing the ore slurry in an electrolytic leaching tank without a diaphragm , the leaching reaction is carried out under the action of an electric field, but this method uses a DSA anode and a titanium cathode coated with iridium tantalum oxide, and the cost is relatively high

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