Abstract

MALULEKE, K.C. et al. Preliminary investigation into the extraction of light rare earth elements from different resources using the sulphation roasting process. J. S. Afr. Inst. Min. Metall. [online]. 2020, vol.120, n.5, pp.319-325. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/778/2020.

Rare earth elements (REEs) are commonly extracted from various resources using hydrometallurgical processes. However, these processes tend to be unselective, with high co-extraction of gangue components. Co-extraction of gangue elements is undesirable as it complicates downstream separation and purification processes. Preliminary tests were conducted on synthetic cerium oxide (chemical grade CeO₂) to investigate the technical feasibility of the sulphation roasting process for the extraction of REEs from different resources. Sulphation roasting was also applied to a REE-bearing ore under selected conditions. The highest REE extraction efficiency of 89% from synthetic CeO₂ was achieved under sulphation roasting conditions of 700°C over 24 hours in a gas atmosphere made up of 32% SO₂ and 16% O₂ (2:1, SO₂:O₂ ratio). The extraction efficiencies from the REE-bearing ore were 47% Ce, 46% La, and 67% Nd, 4% Fe, and 10% Mn after sulphation roasting at 750°C for 24 hours. These preliminary results indicate that it may be feasible to produce REEs from different resources using the established selective sulphation roasting process.

Keywords : rare earth elements; selective extraction; sulphation roasting.

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