Thermodynamic study of oxide phase compositions at reducing iron ore coosit by coals of Karazhyra deposit

Abstract

Application of coals as reducing agents in the direct iron reducing process is a perspective way. For solid-phase iron reducing from iron ore concentrate of Bapy deposit, Republic of Kazakhstan, application of coals of Karazhyra deposit was proposed. Chemical composition of iron ore concentrate of Bapy deposit is presented. By application of methods and means of thermodynamic simulation, analysis of oxide phase composition was carried out. As a result of thermodynamic studies, it was revealed that at reducing of concentrate of specified composition, iron and aluminum oxides, magnesium, calcium, barium, and alkaline metals silicates, sulfides and phosphor compounds are presented in the oxide phase. A dependence of oxide phase parameters on temperature and coal rate was established. It was shown that a number of aluminum oxide, titanium and barium compounds and calcium and magnesium silicates is not practically varying within the whole temperature interval. The number of compounds, containing phosphor, potassium, natrium is decreasing while temperature is increasing due to elements transferring in gas phase. The number of sulfides is decreasing with temperature increase till the whole disappearance in the condensed phase. The number of iron oxides at the temperature higher 872K depends only on reducing agent rate. The number of oxide phase at the temperature lower 853K is maximum, then begins to decrease while the temperature is increasing, the reducing processes are developing and at the temperature of 1013K after completion of reducing process it reaches its maximum value which is not changing then up to temperature 1773K. The studies carried out enable to evaluate slag properties at elaboration of resource-saving technologies of iron direct reducing and can be used at forecasting and evaluation of metallization processes and the further re-melting of materials obtained from Bapy deposit iron ore concentrate of and Karazhyra deposit coals.