Method for decomposing vanadium slag with solution of potassium hydroxide under normal pressure

Abstract

The invention relates to a method for decomposing vanadium slag with solution of potassium hydroxide under normal pressure, which comprises the following steps: adding the vanadium slag or pre-treated vanadium slag, water and KOH into a reactor, controlling the mass ratio of the KOH to the vanadium slag and the concentration of solution of KOH, performing oxidation reaction in the presence of oxidizing gas, and controlling the reaction temperature and reaction time in the reaction process; diluting the obtained reaction slurry with a diluting agent to obtain mixed slurry which contains potassium hydroxide, potassium vanadium, potassium chromate and tailings; and performing filtering separation on the mixed slurry to obtain the tailings and vanadium and chromium-containing aqueous solution. The method is only operated under normal pressure, is easy to perform and has high safety; the operation temperature is far lower than the traditional vanadium extraction temperature; the extraction rate of vanadium is high; and synchronous extraction of chromium in the vanadium slag can be realized. The total amount of the vanadium in the tailings is 0.2-1 weight percent (based on the amount of V2O5) and the total amount of the chromium is 0.2-1 percent (based on the amount of Cr2O3).

Description

technical field [0001] The invention relates to a method for wet treatment of vanadium slag, in particular to a method for decomposing vanadium slag under normal pressure with a potassium hydroxide solution. Background technique [0002] Vanadium is an important metal element, which is more and more widely used in various industrial fields because of its many special properties. About 85% of vanadium in the world is used in the steel industry, mainly as alloy additives to improve the strength, toughness, ductility and heat resistance of steel, and the remaining 15% is used in such fields as aerospace alloys, vanadium batteries, chemical industry, catalysts and other production fields. Chromium is also a metal with important strategic significance. Chromium salts are widely used, involving 15% of the national economy's commodity varieties. Vanadium and chromium are important strategic metal resources in China. With the recovery of my country's economy and the development of...

AI Technical Summary

Problems solved by technology

Using the traditional process of 850°C high-temperature sodium oxidation roasting-water immersion-ammonia salt precipitation of vanadium, the reaction mass transfer effect is poor, even if multiple high-temperature roasting is used, the single-pass recovery rate of vanadium is only 80%

Since the chromium spinel sodium oxidation roasting needs to be operated at a high temperature above 1100°C, in the traditional 850°C high-temperature roasting process to extract vanadium, the chromium spinel in the vanadium slag is difficult to decompose, and only about 10% of the chromium is oxidized to Hexavalent chromium, the vast majority of unconverted chromium resources enter the tailings and fail to be utilized

[0005] Chinese patent CN101215005A proposes a method for roasting vanadium slag and sodium salt (sodium carbonate, sodium chloride) or potassium salt (potassium carbonate, potassium chloride). This patent is suitable for high silicon and low vanadium vanadium slag, and the roasting temperature is 700 ~820°C, multi-temperature stage roasting, by controlling the temperature system and salt ratio, it can prevent the furnace material from sintering, make the process go smoothly, and also reduce the roasting holding time, and the V in the tailings 2 o 5 The content can reach 0.5~1%; Chinese patent CN1884597A, CN86108218A etc. all have carried out different improvement to the additive of sodium roasting process and temperature system, and basic principle all is 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. The problem of high traditional craft

[0008] The treatment of existing patent documents basically adopts high-temperature roasting method to treat vanadium slag, and there is no patent or report on using potassium hydroxide solution to treat vanadium slag to extract vanadium

Images