Preliminary investigation into the extraction of light rare earth elements from different resources using the sulphation roasting process

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.