Geochemical aspects of the mining and processing of the large-tonne mineral resources of the hibinian alkaline massif

Abstract

This article presents an analysis of the influences of nature and production factors relating to the chemical-mineralogical composition of products that formed at the stages of mining and processing apatite-nepheline ores in the Khibiny Mountain Massif. It is shown that all main production processes are connected to the formation of dump waste products that are subject to further changes under the influence of exogenous factors, which include conditions of outdoor storage in dumps and sludge accumulators. According to the dead tails (stale tails) of apatite production, the characteristic changes in the chemical-mineralogical composition and grain-size distribution are determined and have a significant effect on the indicators of their mineral processing. The experimental study of dead tails includes processing a set of technological operations, and their flowsheets are also determined. These flowsheets provide a nepheline concentrate of the required composition with indicators no worse than when processing the tailings of the current composition. It is shown that the existing flowsheets for apatite or nepheline concentrate processing lead to the accumulation of significant amounts of mulls associated with the separation of less valuable components of raw materials into the dump waste products, including calcium and silica. The experimental work also demonstrates the conversion process of gypsum wastes produced during the production of phosphoric acid and shows the importance of additional hydrochemical treatment of belite mull to achieve an economically justified ratio of the main and by-products in the processing of aluminosilicate raw materials.