Research On Deep Reduction Technology Of Oolitic Hematite

In the last few years, Chinese steel industry has developed significantly and therefore domestic iron ores can not meet the tremendous demands of steel companies. China has imported more iron ore than any other country in the world since2003. The imported iron ores in2009reached628million and increased by41.6%compared with2008. Chinese demand for iron ore keeps rapid growth, and so it has become an important issue for the sustainable development of Chinese steel industry to explore domestic resources and reduce the dependence on imported ore.There are a lot of refractory iron ore resources in China which can not be developed and utilized fully because they are difficult to separate and concentrate. Deep reduction technology, a process in which mineral processing is put after smelting, is effective in treating refractory iron ores. Therefore the refractory iron ores can be utilized and Chinese dependence on imported resources can be reduced.In this paper, researches were done on hematite from some place. This oolitic hematite is an extremely refractory iron ore. Iron minerals are fine and have close association with other iron minerals and gangue. Thereby this hematite can not be treated effectively by traditional beneficiation methods.Deep reduction technology was adopted to deal with this oolitic hematite in this paper. Roasting temperature, roasting time, thickness of the samples and ratio of iron to coal were influential factors in experiments. The results indicated that, in temperature range1448-1573K, the higher the reduction temperature was, the better effect was observed and the optimum temperature was1523K; the increase in roasting time was in favor of deep reduction reactions and the suitable roasting time was determined to be30min, considering both reducing effect and economic benefit; thickness of samples showed a great effect on deep reduction and the suitable thickness was determined to be30mm; good reduction effect was obtained when the mass ratio of iron to coal was2:1; the grain size of samples showed weak influence on concentrate grade and recovery and size were determined to be2mm; the coal size of samples were determined to be1.5mm.Deep reduction-magnetic roasting was investigated in this paper, and therefore a theoretical basis can be provided for further researches.