Study On Comprehensive Utilization Of High-chromium Vanadium Slag

High-chromium vanadium titanium magnetite high chromium vanadium slag in the comprehensive utilization process,which contains China’s important strategic reserves of vanadium and chromium,unreasonable use of high chromium vanadium slag is not only a waste of resources will also bring huge environmental problems.In this paper,the technology of sodium roasting,water leaching,removing impurity,precipitation of vanadium,reduction of chromium and tail residue of sodium removed into blast furnace was used to comprehensively utilize high-chromium vanadium slag.The following conclusions are drawn from the above research.Vanadium and chromium mainly occurs in the spinel phase accounted for about 29%of high-chromium vanadium slag.Sodium salt can reduce the oxidation temperature of high chromium vanadium slag,and can react with vanadium chromite spinel to achieve the extraction of vanadium and chromium from high chromium vanadium slag.The process parameters of sodium roasting water leaching were as follows:calcination temperature 850℃,sodium salt ratio of 50%,calcination time 120min,80℃ leaching 30min with liquid solid ratio 2:1.Ammonium magnesium compound salt can remove impurities such as As,Si,and P in the leaching solution containing vanadium and chromium.The addition amount of medicament is 10 times the theoretical amount of ammonium salt,the theoretical amount of magnesium salt is about 5 times,the temperature is about 80℃,the pH value is 9,the time is 1hour.Under the condition of pH 1.8 and the temperature of 120℃,under the condition of 180min reaction,the precipitation rate of vanadium can be reduced by 90%,and the rate of chromium loss is about 5%by the hydrothermal method.The process parameters of reduction and precipitation were as follows:reducing the pH<4,reducing the dosage to 1.1 times of the theoretical amount,at room temperature,the reaction of was about 30 min,and the optimum pH value of precipitation of chromium was 6.9.The high chromium content in the tailings can be detoxified by adding 15%of the pulverized coal to 30min at a temperature of 1000℃.The slag can be returned to the blast furnace after the removal of sodium by the lime hydrothermal method,and the parameters of the sodium removal process are as follows:the sodium removal temperature is not less than 160℃,the time is 2 hour and the liquid solid ratio is not less than 5:1,and the CaO/Na2O is greater than 2.Finally,the vanadium oxide product with V2O5 content of more than 99%was obtained,and the Cr2O3 content was more than 98%.