Experimental Study On Industrial Pure Iron Production Using Iron Ore In Liaoning

Industrial pure iron is a kind of iron alloy,which contains no less than 99.5%iron and no more than 0.04%carbon.It is often used in the production and manufacture of precision alloy,electric alloy,super alloy and clean steel etc,for its advantages of low coercivity,high toughness,strong corrosion resistance,and good thermal and soft magnetic properties.With the progress of technology,the requirements for quality of industrial pure iron,preparation technology and cost are becoming more stringent.Aiming at the current states of long process and high carbon emission of traditional industrial pure iron production,the research of preparation and procedure of industrial pure iron was undertaken,using iron ore concentrate produced in a certain area of Liaoning Province,by the short process and low cost preparation technology of "iron concentrate-high purity iron concentrate-direct reduction-electric furnace melting separation" for industrial pure iron based on impurity element content source control.In this paper,the chemical composition,gangue type and occurrence state of iron concentrate were analyzed at first,then high purity iron concentrate was obtained by two step grinding-magnetic separation,and its process parameters were studied.The obtained high purity iron concentrate was directly reducted with H2 to obtain ultrapure iron powder.The reduction process and reaction mechanism of H2 flow rate on the reduction process,with the analysis of the reduction thermodynamics.At last,the influencing factors of different metallization rate of pellets and high temperature alkalinity on smelting process were explored and industrial pure iron of high purity was prepared by electric furnace melting separation technology.Reserach results are as follows:(1)The rate of particle powder refinement had a good linear relationship with the square of the ball mill speed.The higher the speed was,the greater the ball material ratio and the energy carried by the ball were,leading to more energy carried by the powder,which were easier to be refined,so that the efficiency of milling was greatly improved.with the extension of the duration,the content of fine powder increased;in the initial stage of milling,the effect of powder refining was obvious,and with the extension of duration,the effect decreased.(2)The iron concentrate with 65.97%total iron and 3.61%SiO2 was used as the raw material.The iron concentrate with purity if 70.96%iron,0.55%SiO2 and iron recovery of 83.90%was obtained by a single grinding process,which was simple,economic and technical indicators ideal.(3)The kinetic model of the direct reduction process of high purity iron ore pellets was discussed preliminarily.The kinetic parameters were calculated to determine the interfacial chemical reaction in the direct reduction process.The apparent activation energy of the reduction reaction was 85.27 kJ·mol-1.(4)In direct reduction,the effect of reduction temperature and reduction time on the reduction degree and metallization ratio of pellets was investigated.In the temperature range from 850? to 950?,the reduction rate of the pellets increases gradually with the reduction temperature increasing,and the time required for the reduction stabizing decreased gradually and the metallization ratio of the reduction pellets increased.in same reaction time,the reduction temperature increased with the reduction of iron oxide,which was beneficial to the metalization rate of reduction product.However,the effect decreased to some extent with the increase of temperature.(5)The effect of different pellet metal.lization rate and reduction basicity on the total iron content of the melted product was investigated.Controlling the content of FeO in slag,was good to to increase the total iron content of the melting products and reduce the reduction task in the direct reduction stage.With the increase of basicity,the total iron content of melting production increased,which was helpful to remove impurity elements.