Texture and Mineral Composition of Magmatic Apatite-Nepheline Ores: Technological Consequences (Exemplified by Khibiny)

The paper considers the relationship between textural and structural features and gross mineral and chemical composition of minerals and the physical properties of apatite-nepheline ores and their processing. It is noted that the change in the physical properties of ores involves primarily the change in their mineral composition due to apatite depletion. An increase in the content of nepheline and pyroxene to 35-55 % sharply increases the ore strength up to 47-104 MPa, which entails the growth of energy consumption for grinding. An important factor is that the ore contains high-strength poikilitic intergrowths of apatite with nepheline, pyroxene, and titanite, in which about 20 % of fine-grained apatite is concentrated, and the extraction of which is a complex technological problem. The authors attribute a change in the chemical composition of apatite to the main factors deteriorating the product quality. According to the studies, the chemical composition of apatite is unstable and varies in the content of P 2 O 5 (37.20-42.6 %), SrO (2.29-5.36 %), and Tr 2 O 3 (0.51-1.05 %). It is noted that a change in the composition may affect the flotation properties and quality of the concentrate.