Production of potassium feldspar concentrate from a low-grade pegmatitic ore in Turkey

Abstract

This paper describes the possibility of producing various grade feldspar concentrates by magnetic separation and flotation. A representative sample was obtained from the Manisa–Demirci region. It was composed of 5·94% K₂O, 3·14% Na₂O, 0·61% CaO, 0·41% MgO, 0·11% TiO₂, 0·65% Fe₂O₃, 15·7% Al₂O₃ and 73·08% SiO₂ as determined by the XRF technique. Microscopic studies on thin sections revealed that muscovite, biotite, tourmaline, sphene and rutile were disseminated in various sizes ranging between 20–500 μm in the matrix of orthoclase, albite and quartz, and for an adequate liberation the sample had to be ground to –300 μm. The non-magnetics were a basic mixture of feldspars and quartz with an alkaline content of 5·86% K₂O and 2·96% Na₂O, which was raised to 13·44% (9·22% K₂O + 4·22% Na₂O) by only feldspar flotation. For further improvement of K₂O, orthoclase was differentially floated while albite was simultaneously depressed with NaCl. Finally, a high-grade potassium feldspar concentrate was produced composed of 12·65% K₂O, 3·1% Na₂O, 0·11% Fe₂O₃, and 0·04% TiO₂ with a glossy white firing button at 1200°C.