Assessment of U. S. domestic capacity for producing reactor-grade thorium dioxide and controlling associated wastes and effluents

ThO2-based pellet fuels - their properties, methods of fabrication, and irradiation performance: a critical assessment of the state of the technology and recommendations for further work

“…The deposits are mined by suction dredging or excavation and concentrated by gravity and magnetic separation. The resulting monazite concentrate is then processed by digestion with caustic soda or sulfuric acid and step-wise precipitation of thorium and rare earths using ammonium hydroxide (Enderlin 1978).…”