Physical And Chemical Behavior Of Fe And Mn Impurities In The Reduction Process For Sponge Titanium Production By Kroll Process

With the development of high-tech materials in the titanium field,the quality requirements for high-quality sponge titanium are getting higher and higher.The content of impurities in sponge titanium is an important index reflecting the quality of sponge titanium and the level of reduction and distillation.The uneven distribution of impurities makes sponge titanium divided into many grades of titanium,so the distribution of impurities is an important factor that affects the grade classification of sponge titanium.In order to control the content of impurities,it is necessary to clarify the specific input and output of impurities in the production and the distribution of impurities.However,at present,researchers have only conducted qualitative research on the input of impurities,but never quantitatively research and analysis the input and output of impurities;As for the study of the distribution of impurities,the researchers only divided the area by higher or lower concepts,and never have a quantitative description of the content of impurities.It is the shortage of these studies that has resulted in insufficient knowledge of the physicochemical behavior of impurities,resulting in no clear direction in controlling the content of impurities.Therefore,this paper based on the input-output analysis method,combined with the industrial production characteristics of sponge titanium,the input-output model was established,and the input-output amount of impurities was calculated based on this model.Based on the flow analysis of the impurities,the input and output of impurities in the reduction and distillation process,product sorting process and magnesium processing process were obtained.The results of the study clarified the ins and outs of impurities,and concluded that the solubility of Fe and Mn in Mg is much higher than the solubility in Mg Cl₂,so a proposal of reduce the Mg excess coefficient is proposed.On the basis of impurities input-output analysis,the proportion of impurities from different input is calculated,simultaneously calculated the mass fraction of impurities in qualified sponge titanium and waste titanium.Based on these results,the physical and chemical behaviors of Fe and Mn impurities sources are analyzed theoretically.It is found that Fe impurity is mainly input by the equipment,Mn impurity is mainly input by the raw material Mg,and the chemical reaction equations of Fe and Mn impurities in the reduction process are determined.In order to further explore the behavior of impurities and the distribution law of impurities.This paper takes the titanium in industrial production as the experimental object,after sampling and preparing samples,the contents of Fe,Mn and Mg impurities in the samples were determined by ICP-AES method,and the contents of Cl impurity in the samples were determined by silver chloride spectrophotometry method.After sorting out the experimental data,the impurities distribution nephogram is made according to different positions and corresponding impurity content,and the highest and lowest values of impurities content in the whole titanium lump are obtained.The impurities content is classified according to the distribution nephogram,and the proportion of impurities content of different grades in the whole titanium lump and in different reduction stages is calculated.Then,according to the distribution of impurities on the cross section,the radial direction analysis of titanium lump is carried out,and the linear correlation between cross section position and impurities content is analyzed.Finally,the axial direction analysis of the titanium lump is carried out,the distribution figure of impurities in the axial direction of the titanium lump is made,and the change of impurities content in the axial direction of the sponge titanium is analyzed.