1. Ndwedwe kaolin feasibility study;Coates,1976
2. The production of alumina from Natal kaolinites;Edwards,1988
3. A technological comparison of six processes for the production of reduction-grade alumina from non-bauxite raw materials;Bengston,1979
4. Investigations on the production of low iron-content aluminium sulphate from clay;Siebert,1971
5. Alumina from clay—a nitric acid process;Dewey,1979