Technology elaboration for borate ore utilization at iron ore pellets production

Abstract

Input of intensifying additives, influencing the strengthening of iron ore pellets, can be one of methods to strengthen the pellets and to decrease the volume of fines in them. Boron oxide ore borate ore can be used as such additives. Study of technology aspects of boron-containing pellets production and elaboration of technology of boron input into Kachkanar vanadiumcontaining raw materials was the purpose of the study, aimed at exclusion from BF burden of sinter, which does not contain vanadium. A possibility was justified to use borate ore at iron ore pellets production by a partial substitution of bentonite. Influence of borate ore additives on pellets metallurgical properties studied. As a result of laboratory studies it was determined, that the borate ore has not binding properties and its utilization is possible only in a mixture with bentonite. Optimal content of borate ore in pellets determined, exceeding of which a decrease of reducibility is observed, accompanied by a considerable swelling, which makes impossible the utilization of such pellets in blast furnaces. It was shown, that input of optimal volume of borate ore additives enables to keep the reducibility and swelling at the level of Kachkanar pellets being produced. The mechanism of borate ore content influence on strength characteristics of burnt pellets and their behavior during reducing studied. The regularity of borate ore additives influence on cold and hot pellets strength determined. It was determined, that at input of 0.5% of borate ore practically does not influence on the pellets reducibility while swelling will be constant. The input of borate ore up to 2% will result in a sharp increase of swelling. The decrease of reducibility with simultaneous increase of swelling of pellets having more than 0.5% of borate ore does not allow using such pellets in blast furnaces. Recommendations provided for slag regime optimizing, decreasing of metal losses with slag and test BF heats of pellets, having optimal additives of borate ore and bentonite carrying out.