Abstract

HAVENGA, J.L  and  NEL, J.T. The manufacture of plasma-dissociated zircon (PDZ) via a non-transferred arc process utilizing three 150 kw DC plasma torches. J. S. Afr. Inst. Min. Metall. [online]. 2012, vol.112, n.spe, pp.497-500. ISSN 2411-9717.

South Africa produces about 400 Kt zircon (ZrSiC>4) per annum. This represents about 30 percent of the global demand. However, very little is beneficiated locally and more than 95 percent is exported with little or no value addition. Zircon is a very inert material and needs to undergo high-temperature alkaline melting processes to produce valuable zirconium products. The conversion of zircon to plasma-dissociated zircon (PDZ) produces a chemically reactive species (ZrO₂.SiC>2) which consist of finely divided submicron monoclinic ZrO₂ crystals dispersed in a SiO₂ matrix. In this paper, an in-flight, non-transferred arc pilot plasma plant with a capacity of 100 kg/h and which consists of three 150 kW DC plasma torches, is described. The optimization of the plant, which includes the use of different zircon concentrates, the influence of particle size, feed rates, plasma gas, and energy utilization, is discussed.

Keywords : plasma-dissociated zircon; PDZ, DC arc; non-transferred arc; plasma.

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