Thermomagnetic concentration and dephosphorizing of brown clay iron ore and concentrates

Abstract

Oolitic brown clay iron ores are of prime economic importance because of their enormous stocks in the world. However, their use in metallurgical production is very severely limited at the present time because of the high content of phosphorus in them. The process of phosphorus extracting from these ores almost cannot be realized by the known enrichment methods, since phosphorus presents in oolites in the emulsionated and impregnated state, without forming the independent minerals in this case. Therefore, using of ores of the given type is very limited. Growth of the world steel production at this time has considerably increased demand for iron ore, for that reason in the last decades in the world there were made considerable efforts on creation of new manufacturing schemes of brown clay iron ores obtaining standard iron ore concentrates. Considerable reduction of rich and easily beneficiated iron ores in Kazakhstan results in necessity to attract in metallurgical production the huge resources of the easily extracted ooli tic brown clay iron ores of Lissakovsk, Ayat, Priaral, and other fields with the iron content from 35 to 40  % and phosphorus up to 1  %. The technology of thermomagnetic beneficiation is represented as the most self-sustainable and acceptable dephosphorizing technology of brown limonites. The essence of the technology consists in the reproduction by liquid hydrocarbon reducer (LHR), mesmerizing roasting of the concentrate, magnetic concentration of the roasted raw material receiving the magnetic concentrate with the subsequent dephosphorizing of the obtained concentrate by the acid leaching method. The technology was tested in pilot conditions by representative samplings of the Lissakovsk concentrate and the ores of Ayat and Kokbulak fields.