Optimization Study On Preparation Of High Titanium Slag By Pre-reduction/Electrical Furnace Smelting From Ilmenite

As the main raw material of titanium industry, ilmenite is of abundant reserve and low cost, as well as the low grade of TiO2, thus it needs to be upgraded to Ti-rich material, which become the main crucial step in titanium industrial production processes, especially when the environmental requirements become much more strict today. Therefore, the basic research of finding a way which have high efficiency and low energy consumption in product the Ti-rich material is great significance in the development of the titanium industry.Electric furnace method which could product the Ti-rich material efficiently is predominant among those Ti-rich material preparation methods, but it still have the problem of high power consumption and smelting difficultly. pre-reduction/electrical furnace method for taking its advantages of energy saving and sulfur reducing in product. Therefore, it is of great importance to research further on the pre-reduction/electrical furnace method.Ilmenite resource as the raw material, additives, high pressure roller grind (HPRG) pretreatment, pre-oxidization, or a combination thereof, were investigated in this dissertation to optimize the pre-reduction step of ilmenite. From the study of basic principles of the electric furnace smelting, titanium slag performance and its factors, the slag type, and the key parameters of the smelting furnace, the conclusions were reached as follows:(1)The reduction efficiency of ilmenite was improved and the metallization rate of products was also increased when the raw material was added by additives, or pre-oxidized, or pretreated by HPRG. The effects of pre-oxidized was the best, and in the next places are HPRG and borax added.(2) The combination of pre-oxidation and additive is efficient to the reduction of ilmenite. However, the combination of HPRG and pre-oxidation, or the combination of HPRG and additive, are helpless even harmful for the reduction as the metallization rate was higher than HPRG only, but lower than pre-oxidation only. Taking the effects of ilmenite reduction and the strength of product into account, the combination of pre-oxidation and HPRG was considered as a optimal method to enhance the pre-reduction of ilmenite after the comprehensive analysis of the effects of those enhancements on the metallization rate and strength of products, cost, influences to the electric furnace smelting and so forth. The recommended condition was that pre-oxidization at1000℃for20min, then pre-reduction at1050℃for60min.(3) After the analysis of the phase composition in slag, melting temperature, FeO content, the key factors to electric furnace smelting of ilmenite are summed up, that are smelting parameters (smelting temperature and carbon content, etc.), control of FeO content in the smelting process (about7%), and phase composition in slag (to avoid the generation of TiC, TiN). The good separation of slag and Fe was generated when ilmenite was smelted for60min in1600-1650℃。It was best effect of smelting when the carbon content was5%, getting the high TiO2of70.52%.