Mining Institute, Kola Science Center, Russian Academy of Sciences, Apatity, Russia

A. S. Opalev, Deputy Director of Science, Candidate of Engineering Sciences
S. A. Alekseeva, Senior Researcher, s.alekseeva@ksc.ru

EuroChem Mineral and Chemical Company, Moscow, Russia
I. S. Barmin, Head of School, Candidate of Engineering Sciences

Kovdor Mining and Processing Plant, Kovdor, Russia
N. A. Smirnova, Chief Dresser

The article presents the studies on the potential increase in the volume of processing of magnetite–apatite ore from the Kovdor deposit. To solve this task, improvement of ore pretreatment through the preliminary screening before the first stage rod milling is discussed. The analysis of an actual dressing plant operation finds out that the feed of the first stage rod milling contains more than 30% of the finished class of -2 mm, which can be taken out of the mill feed and sent directly to magnetic separation. The study focused on the effect of the pre-screening operation on the indicators of milling and subsequent magnetic separation. The studies determined the coefficient of relative grindability of different-size ore, analyzed the influence of the pre-screening coarseness on the amount of the pay class in the milled product and on the dynamics of dissociation of magnetite and apatite, and estimated the magnetic separation efficiency after the milling in the improved regime. The implemented research shows that processing circuit reaches the largest increment in productivity by 22% at the pre-screening output coarseness of 0.56 mm. The economic efficiency of the new pretreatment technology introduced at the first stage of ore processing lies in the higher productivity and, accordingly, in the larger volume of marketable products at a processing factory. Since the technology implementation needs no growth in number of milling equipment, which is most energy-intensive in mineral beneficiation process, it is expected that economic performance of the whole mining and processing plant also improves.

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