Potash Refining. The Sylvinite ores mined in conventional mines contain Sylvite (20 to 30% K2O), Halite, sometimes Carnallite and 1 to 5% insol. Liberation, in some cases, is substantial at 1 cm (3/8 inch), and virtually complete in all cases at 14 mesh. The separation processes include dissolution of the Carnallite, and removal of the insols ...Web