Beryllium—Geochemistry, Mineralogy and Beneficiation

Abstract

This paper presents a review of the geology, geochemistry and mineralogy of beryllium, and methods of beneficiation of beryl including the safety measures to be adopted while crushing and grinding of beryllium minerals. A typical lithophile element, beryllium forms a characteristic four fold coordination with oxygen forming the [BeO4]6− complex. Geochemically it accumulates in the acid and alkalic magmas during magmatic differentiation process. During crystallization of these two magmas beryllium follows different course; in the case of acid magma it gets concentrated in the residual pegmatitic and hydrothermal stage, while in the case of alkali magma it enters into the lattice of several rock forming and accessory minerals by diadochic capture preventing its concentration in the residual stage. Beryllium enters in the structure of as many as 40 minerals as an essential constituent and another 50 minerals as occasional and minor diadochic constituent. Of the 40 beryllium minerals, 26 are silicates reflecting the close geochemical similarity of [BeO4] 6− complex with [A1O4] 5− and [SiO4] 4− complexes. Beryl, Be3Al2[Si6O18] and bertrandite, Be4[Si207l are the ore minerals exploited as a source of beryllium. The physical, optical, chemical and paragenetic properties of beryl and bertrandite are described in detail. While beryl occurs in heterogenous zoned pegmatites, bertrandite comes from nonpegmatitic sources. Hand sorting and picking continues to be the principle means of concentration of beryl and bertrandite. However considerable studies have been reported on the application of flotation for the recovery of fine beryl in milled products. A review of literature on various aspects of flotation of beryl using both anionic and cationic collectors is presented.