Research On Producing Ultraclean Industrial Pure Iron

Ultra pure iron is a important basic iron and steel materials, it can be used chiefly to refine various high temperature alloy, heat-resistant alloy, accurate alloy, maraging steel and so on for aerospace ,army plant and civil.it has a rapid development in recent years. Developing this technology of the high pure iron can improve the purity of the iron and enlarge the scope of application. In domestic country, the preparation technology of the ultra pure iron is not mature, the supply don't meet the demand. But the sponge iron refining the ultra pure iron in the vacuum induction furnace has many merits, firstly, using the sponge iron as raw materials, the price is very low relatively and the production is increasing gradually; secondly the residual elements(Pb,As,Sn,Sb,Bi,Cu and so on) in the sponge iron is very low, it can be used to tured out very ultra pure iron.Experiments were carried out in the lab to refine industrial pure iron by sponge iron in the 25Kg medium-frequency induction furnace and 25kg vacuum induction furnace. The main research content includes the thermodynamic and kinetics analysis of deep dephosphorization of the sponge iron , selecting of dephosphorizing slag and influencing factor of deep dephosphorization and so on. The sponge iron was refined in the induction furnace and the finial phosphorus content in the steel is about 10ppm.After that, The thermodynamic analysis of the steel deep desulfurization was carried out ,the influence of the melting point of slag, the mechanically mixed slag and premelted refining slag on desulfurization was discussion through the experiments. Several times deep desulfurization experiments was carried out in the induction furnace, it concluded that some conditions must be meet for the deep desulfurization of the liquid steel through the thermodynamic analysis and the experiments date, finally the sulfur content in the steel was reduced to about 10ppm in the induction furnace.The research proved that the ultra pure iron can be turned out by using the sponge iron or driect reduction iron in the induction furnace if the thermodynamics conditions and the fitting slag of dephosphorization and desulfurization are be controlled well. There will be a good prospect in future if the technology can be used in the industrial process.