Producing Ferromanganese From Oxidation Manganese Ore Based On Solid Phase Reduction With Carbothermic Method

About90%production of manganese in world are used in steel industry, manganese have important effect in steel especalily in improving the strength, toughness, hardness and quenching performance. Manganese is added in steel by the form of ferromanganese or ferromanganese-silicon alloy. But there are some probolem in the producing manganese alloy like high energy consumption, long process, heavy pollution and so on. Therefore, a new type of low energy consumption and pollution-free manganese resources utilization method has become the hotspot in research.In this paper low grade manganese oxide is used as the research object, the theoretical foundation of the alloy ferromanganese producing process and controlling conditions are researched by carbonthermal reduction in solid phase condition, the best parameters in reduction process are obtained by researching the thermodynamic process and the law of parameters in reduction process.Thermodynamics investigation with carbothermic indicates that indirect reduction reaction is the major way for high valence manganese oxide turning into low valence manganese oxide. The last reduction step is MnO turning into Mn, Mn3C or Mn7C3at1698K,1666K,1615K, which means Mn3C or Mn7C3is easily generated than Mn.Parameters of carbothermic in solid phase reduction process show that:the carbon in reduction process play the role of the performance for three aspects:carbon acts as reducing agent the reduction process, carbon is the intermediate in solid-solid reaction, carbon can promote metal phase condensation. Basicity deciding the generation of C2S and phase change in the process of cooling, phase change is the foundation of slag and metal separation, the min basicity should be no less than1.6for phase changing. The function of additive is promoting performance in metal condensed, reduced tension between slag and metal interfacial. A certain amount of additive can increase distribution of manganese between slag and metal and reduce the loss of metal elements in slag.Microscopic structure and component products analysis shows that with the temperature rising, FeMn2.6C1.1and FeMn5.5C4.1, changing into FeMn3.6C2.8, FeMn4.6C4, FeMn2.2C1.2.With the rise of temperature manganese content in melt metal increase gradually because of the manganese turning from manganese oxide into melt metal. With additive amount changing, the composition of the melt metal change from FeMn2.9C1.5and FeMn4.6C4to FeMn2.9C1.2and FeMn4.oC3by improving distribution of manganese between the slag and metal.Technology research shows that:in the condition that reaction temperature is1450℃, reduction time is30min, carbon coefficient is1.0, basicity is2.0, additive is5%of the total slag, after reaction the products is high carbon ferromanganese, whose composition content is manganese is72%, iron is17%, carbon is6.5%.The mainly innovation points in research are as follows:(1) thermodynamics is used as the foundation for designing parameter in reaction conditions on solid phase conditions to get high carbon ferromanganese products in one step with direct reaction and indirect reaction,(2) phase diagram calculation is used in designing slag and metal separation in the nature condition during cooling process.(3) giving the method of prompting the effect of carbonthermal reduction in solid phase condition and the parameter of additive is explained.