Technique And Mechanism Of Oxidation Roasting Of Vanadium Slag Produced From Pangang Group

oxidation roasting of vanadium slag plays an important role in vanadium industry.However due to the fact that chemical composition and phase structure of vanadium slag is relatively complex,a lot of components including spinel,silicate,and a small amount of iron are oxidized simultaneously in the roasting process.Their oxidation temperature and oxidation rate are different.At the same time,various oxidation products react with each other.Therefore,the phase structure of this process is more complex,so it is necessary for us to conduct a comprehensive analysis of the technique and mechanism of oxidation roasting of vanadium slag.This article takes the vanadium slag of Pangang Group as raw material and carried out oxidation roasting and acid leaching technology.The roasting process and leaching results under various conditions are investigated by changing the factors of roasting temperature,roasting time,the ratio of calcium to vanadium and cooling rate.The roasting effect of roasting temperature,roasting time,the ratio of calcium to vanadium and cooling rate on roasting process is studied.The conclusions show that:under the conditions of roasting temperature at 900 ℃,roasting for 3 hours,the ratio of calcium to vanadium at 0.62 and rapid cooling,the effect of roasting is better and leaching rate can reaches 91.26%.The conclusions are further proved by analyzing and comparing phase difference between roasting clinker and leaching residues under various roasting conditions.The mechanism of oxidation roasting is studied further.The result shows that calcium vanadate is easily formed in thermodynamics.Through the process of roasting thermal analysis experiment,the further phase transformation mechanism during the roasting process is found including the main chemical reaction,the main phase change process,the effect of silicate to the degree of oxidation,the distribution of vanadium in slag and the appearance of liquid phase in the process of roasting.Through the research above,The mechanism of vanadium loss in roasting clinker is identified.The main reasons are the influence of silicate,the oxidation state of spinel,the state chage of vanadium and the existing way of calcium.Then effective measures are put forward.