State and development options for the raw material base of aluminum in non-bauxite regions

Abstract

Aluminum production is the basis for the leading industrial sectors and ensures the stable growth of any national economy. However, many regions of the world have limited or zero reserves of bauxites, which necessitates the use of alternative raw materials. Kaolinite ores and clay rocks are among the leading alternatives, with their global reserves estimated at 20–25 billion tons and occurrence confined to various non-bauxite regions. The current mining and processing of kaolinite raw materials has an established infrastructure, is provided with raw materials and, in the long term, may be adapted to the production of alumina and associated products. The chemical composition of kaolins at industrially mined deposits in various regions was studied using the X-ray fluorescence method, with the material composition determined by X-ray diffraction and by the combined method of differential thermal and thermogravimetric analysis. It is shown that, regardless of the region of formation and occurrence, all kaolin ores have the same chemical and mineral composition with a fairly stable content of basic chemical elements and minerals. This largely determines the technology for their processing into alumina and by-products. The results are presented for calculating the theoretical consumption of reagents and the yield of products per 1 ton of Al2 O3 in kaolinite processing by sintering of a three-or two-com-ponent charge with subsequent leaching of the sintered material. It is shown that reasonable selection of the processing method for a particular raw material depends on the chemical and mineralogical characteristics of the latter and on the technical and economic conditions of the region.