Integrated study on obtaining oxide pellets from brown iron ore

Abstract

Introduction. Currently, the main raw materials for the production of cast iron and steel at metallurgical plants are iron concentrates obtained from magnetite (ferrous) quartzites, titanium-magnetite, and skarn ores. The existing technologies for processing these types of ores, which mainly include separation processes based on magnetic properties, size, separating of equally falling grains, and surface wettability allow us to produce both ordinary iron concentrates and high quality ones. The use of such schemes in the processing of brown iron ore does not allow obtaining high rates of mineral concentration. One of the methods for processing this type of ore is a roasting-magnetic scheme, which allows converting weakly magnetic (non-magnetic) forms of iron into strongly magnetic ones. Research objective is to develop the mode of magnetizing roasting of brown iron ore, technology of concentrating of the burn-out product in order to obtain iron concentrate and oxide pellets. Methods of research. The duration of heat treatment of the charge consisting of iron ore from the Abail deposit and coal from the Ekibastuz deposit and the required mass fraction of solid carbon contained in the coal are determined. Technological studies of the roasted product were carried out in order to obtain a concentrate with a mass fraction of iron at least 67%. According to the developed technology, a batch of iron concentrate was developed in order to obtain and study raw and oxide pellets. Results. The modes of magnetizing roasting of brown iron ore from the Abail deposit and cooling of the roasted material have been developed. A scheme for mineral processing of the roasted material has been developed in order to obtain a concentrate with at least 67% of iron mass fraction. The process of obtaining strong raw and roasted pellets from iron concentrate is studied. Conclusions. The developed mode of magnetizing roasting of the charge consisting of coal and ore from the Abail deposit makes it possible to obtain a roasted product with a degree of magnetization of 93%. The using of desliming of the roasted product makes it possible to remove magnetic floccules from the processing that reduce the concentrate quality, and to obtain a concentrate with a mass fraction of iron of at least 67% in the last stage of magnetic separation. From the iron concentrate, it is possible to obtain oxidized pellets with a strength of at least 200 kg/pellet at temperature of pellets firing of 1325 °C.