Fundamental Research On Separation Of Jilin Linjiang Lingyang Iron Ore

Since1996, the Chinese steel output has kept the first in the world. With the rapid development of steel industrial production, it is caused that swift increase of demand and production of iron ores, and demand of iron ores exceeds supply. Since2003, China has become the largest importer of iron ore in the world. Furthermore, iron ores of383millions tons were imported in2007and the imports of iron ores was up to433millions tons in2008. Authough, the internal output steel has declined due to the effect of global economic crisis, with upgrading of consumed structure of resident and development of industrialization and urbanization, the demand for steel product will increase continuously and steel industry will continue to develop. Thus, the situation that the most iron ores relies on importing from other countries is hard to get torsion in short period.The resource of high grade iron ores is gradually exhausted in China, and then in addition of the price of iron ores rise substantially, so potential iron ores resource have to be developed with strategic and foresighted vision. The major characteristic of the Chinese iron ores is "poor","fine" and "miscellaneous", and average grade of iron in China is32%and lower11percents than that in the world. Not only that, but iron ores of97.5%in China need to conduct mineral processing, and the proportion of complex refractory hematite is greater (20.8%of iron ores reserves). Therefore, it is particularly important to develop the crucial technology of mineral processing for low grade refractory iron ores.In this paper, Lingyang iron ore from Linjiang Jilin (namely Jilin antelope iron ore) was chosen as research object. On the foundation of technology mineralogy research, the effect of various testing conditions on separation results of the iron ore were studied systematacially with different technology, such as magnetic separation flotation, roast-magnetic separation,deep reduction-selection, etc.The study results showed that iron minerals were not separated effectively by the means of conventional magnetic separaton and flotation due to superfine useful minerals in the iron ore and ternary association between useful and gangue minerals.The iron concentrate according with quality requirement could be gotten by roast-magnetic separation technology, that is said, roast-magnetic separation technology was most effective process for Lingyang iron ore. When roast temperature was750℃～800℃and roast time was40-120min, the grade of iron concentrate was up to67%; With secondly bituminite of Hebei Fongning coal as reductant and suitable proportion of coal to iron ore was8%, the grade and recovery of iron concentrate was over58%and about60%respectively. The classification results of roasted products showed that in the reduction clinker, the coarse and medium grain size products were green roasting, however, the fines were complete roasting. Thus, before roasting, it had better crush iron ore to be fine grain size equably.The deep reduction tests were conducted in the box resistance furnace and one-way heating furnace, technique conditions in reduction process were determined. Rduction iron powders with mllization ratio of86.91%, iron grade of88.09%and iron recovery of88.32%were produced in suitable reduction condition and feasible processing flowsheets and technics. The contents of magnesium and calcium in the deep reduction iron powders used washery coal as reduction reagent were low comparatively and contents of silicon and aluminum met demand of direct reduced iron. Furthermore, the growing process of iron particle could be divided into three stages including nucleation, deep reduction and particle growth.Above-mentioned research results provided feasible program and theoretical basis how to use and develop Lingyang iron ore efficiently and reasonably and offer reference for another kinds of complex refractory iron ore.