Analysis Of Affecting Factors Of Oxidized Pellet RSI At Baotou Iron And Steel(Group) And Study On Its Reasonable Control

Because of the K,Na and F is contained in Baiyun Ebo iron concentrate,the RSI of oxidized pellet at Baotou Iron and Steel?Group?is worsened.With the advancement of beneficiation technology,the K,Na and F content of Baiyun Ebo iron concentrate has dropped to a lower level.Especially the K and Na content is lower than or equal to many domestic iron concentrates.The ratio of Baiyun Ebo iron concentrate is generally more than 30%,the RSI of oxidized pellet at Baotou Iron and Steel?Group?is often>20%.In this paper,the effect of trace K,Na and F and the interaction of SiO₂,CaO,MgO,TiO₂with K,Na and F on oxidized pellet RSI at Baotou Iron and Steel?Group?is studied.The reason of deterioration and the measure of inhibition on the RSI of oxidized pellet prepared using Baiyun Ebo concentrate is expanded.A better technical route that flux oxidized pellet is produced using Large proportion Baiyun Ebo concentrate is proposed.The experimental research shows that,because of the trace K,Na and F is contained in Baiyun Ebo concentrate,the oxidized pellet RSI at Baotou Iron and Steel is worsened.The RSI of oxidized pellet prepared using Large proportion Baiyun Ebo concentrate is inhibited Within 20%by adopting technical measure of increasing the content of SiO₂ in oxidized pellet or producing the flux oxidized pellet or increasing the content of TiO₂ in oxidized pellet.The mechanism research shows that,the iron whiskers is forming by catalysis of K and Na.The melting point and the Strength of the slag phase is reduced.The RSI of oxidized pellets is Substantially worsened by Comprehensive effect of F,K and Na.The forming of the iron whiskers and the reduced effect of the melting point and the Strength of the slag phase is inhibited by adopting technical measure of increasing the content of SiO₂in oxidized pellet or producing the flux oxidized pellet.The new minerals is appeared by physical chemical reaction of TiO₂ and Fe₂O₃.Due to the RI of the new minerals under the condition of high temperature is Low,the oxidized pellet RSI at Baotou Iron and Steel?Group?is inhibited.Upper limit of the control standard on flux oxidized pellet RSI at Baotou Iron and Steel?Group?is 25%.The research and development of Fluoride Flux Pellet shows that,If the ratio of Baiyun Ebo iron concentrate is generally more than 85%and the RSI of oxidized pellet at Baotou Iron and Steel?Group?is controlled within 20%,the MgO content of oxidized pellet is controlled between 2.0%and 2.5%.When the SiO₂ content of oxidized pellet is controlled between 2.0%and 2.5%,The upper limit of free alkalinity is 1.2.When the SiO₂content of oxidized pellet is controlled between 2.5%and 3.0%,The upper limit of free alkalinity is 1.0.When the SiO₂ content of oxidized pellet is controlled between 3.0%and3.5%,The upper limit of free alkalinity is 0.9.The green ball performance and the chemical composition of the pellets and the reduction performance and the desulfurization capacity of the Pellet factory at Baotou Iron and Steel?Group?and the iron concentrate supply status was comprehensively Considered.The program of producing flux oxidized pellet that 85%-90%Baiyun Ebo iron concentrate and 10%-15%Purchased iron concentrate and dolomite was proposed.