Decomposition of spodumene mineral in granitic rocks from South Kalimantan - Indonesia by potassium sulphate

Abstract

The decomposition behaviour of spodumene mineral in granitic rock from Kalimantan Indonesia by using potassium sulphate has been studied in this research. The granitic rock from Kalimantan is indicated to contain spodumene mineral. The sspodumene is one of the main minerals which contains lithium. The purpose of this study is to decompose the α-spodumene mineral in the granitic rock of Kalimantan to β-spodumene which is subsequently easier to be dissolved in water. In this study, the decomposition of α-spodumene was performed under variations of roasting temperatures (i.e. 350°C, 450°C, 550°C, 600°C, 700°C, 800°C, 900°C and 1000°C) and roasting times (20 min, 40 min and 60 min). The results of the decomposition products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). It was identified that the granitic rock from Kalimantan consists of α-spodumene (LiAlSi2O6) with lithium content of 3.09 ppm and the other major minerals are quartz (SiO2) and albite (NaAlSiO3O8). The α-spodumene was completely converted to β-spodumene at 700°C for 60 minutes.