Patent ID: 6090353
Filing Date: 2000-07-18
Classification: C01B

Abstract:
A process for removing impurities contained in the crystal lattice of minerals, comprising the steps of:forming a mixture of a mineral capable of structurally reorganizing its crystal lattice and which contains an impurity in its crystal lattice, a halogen anion, water and a matrix-forming additive to facilitate the migration of the impurity from said crystal lattice, said matrix-forming additive is selected from the group consisting of a silicate, and a kaolinite clay;heating the mixture to the structural reorganization transition temperature of the mineral;holding the mixture at the structural reorganization transition temperature for a sufficient amount of time to freely migrate the impurity from the crystal lattice and combine with the halogen anion and matrix-forming additive; andseparating the combined impurity, matrix-forming additive and anion from said mixture to render the mineral essentially free of said impurity.