Study On Shallow Oxidation Desiliconization And Preservation Of Vanadium And Chromium By Injecting Co₂ Into Hot Metal Containing Vanadium And Chromium

The Hongge mine in the Xichang area of Panzhihua city,Sichuan province,is rich in iron,titanium,vanadium and chromium.Thereinto,the chromium content accounts for nearly twice the country's proven reserves.The Hongge mine is currently the largest chromium ore resource in China.Vanadium and chromium are extremely important strategic resources,which are widely used in steel,chemical,pharmaceutical,aerospace,optics and other industries.In order to make full use of vanadium and chromium resources,the grade of vanadium and chromium slag needs to be improved.Because silicon is an important factor affecting the grade of vanadium and chromium slag when blowing vanadium and chromium slag,the process technology for obtaining low silicon and vanadium-containing chromium molten iron is particularly significant.This project intends to use CO2 as a weak oxidant to lightly oxidize vanadium-chromium-containing molten iron,and to separate silicon from vanadium-chromium in the molten iron,and to provide technical support for obtaining low-silicon vanadium-chrome slag.Firstly,the feasibility of desiliconization and vanadium retention during the CO2 shallow oxidation of molten iron and the balance between silicon,vanadium,chromium concentration and temperature in the molten iron were analyzed from the perspective of thermodynamics,which provides a theoretical basis for this experiment.Secondly,experimental conditions of desiliconization and vanadium-chromium retention were optimized.The main conclusions obtained in this project are as follows:(1)Using CO2 as a weak oxidant,the experimental results in the temperature range of 1350?1550 ? show that the oxidation rates of C,Si,Mn,V,Cr and other elements in vanadium chromium molten iron are different,and can be divided into four levels:the oxidation rate of silicon is the fastest and the degree of oxidation is the largest;the oxidation rate of carbon is the second;the oxidation rate of vanadium and chromium is the slowest,but the oxidation rate of chromium is greater than that of vanadium,and the oxidation degree of chromium is also greater than that of vanadium.(2)The optimal process conditions determined through experiments are:the inner diameter of the corundum tube is 3mm,the experimental temperature is 1500?,the flow rate of CO2 is 0.5L/min,and a certain amount of stirring is used.The oxidation rate of silicon can reach about 90%,the oxidation rate of vanadium is about 4%,and the oxidation rate of chromium is about 10%.(3)The desiliconization products sprayed with CO2 in vanadium-chromium-containing molten iron include not only SiO2,but also SiO gas.The distribution of these two products is related to the experimental temperature and the partial pressure of SiO and CO gas.In the experiment,due to the continuous injection of CO2,the partial pressure of SiO gas can be reduced.The experimental results show that in the temperature range of 1350?1550?,as the temperature increases,the proportion of SiO is higher;there are three directions of silicon in the molten iron:[Si]remaining in the vanadium chromium molten iron,forming SiO2 and entering the slag,and the generated SiO gas discharged from the exhaust pipe.