Abstract: Pure alumina (Al.sub.2 O.sub.3) is recovered from alunite (Al.sub.2 (SO.sub.4).sub.3.K.sub.2 SO.sub.4.4 Al (OH).sub.3) which is found mixed with various impurities by first calcinating the alunite in the presence of a chloride to produce impure Al.sub.2 O.sub.3 and other biproducts, and the impure Al.sub.2 O.sub.3 is then contacted with concentrated HCl to produce, after concentration and crystallization, crystals of AlCl.sub.3.6H.sub.2 O. These crystals are then calcinated to yield highly concentrated HCl and pure alumina.

Abstract: The nickel content from low grade nickel lateritic iron ore is upgraded by a combined process of segregation and magnetic separation or flotation. Ground ore is thoroughly mixed with a small quantity of calcium carbonate, calcium sulfate and coke and is sprayed with a solution of sodium chloride to make appropriate pellets. These pellets are gradually heated under a neutral or a slightly reducing atmosphere to a temperature of 1050.degree. C maximum for up to 90 minutes. Roasting at this temperature is carried out for a predetermined period of time so as to convert all the nickel from the ore to a metallic condition. The roasted material is cooled, ground in a water medium and finally subjected to a wet or dry magnetic separation or flotation separation treatment so as to obtain a rich nickel concentrate.The process may be carried without forming pellets merely by thoroughly mixing the ground ore with sodium chloride, limestone, gypsum and coke.

Abstract: Magnesite ores are upgraded by the removal of the contaminants from the ore by a reverse flotation treatment thereof. Removal is carried out with the aid of a mixture of quaternary ammonium compounds and primary amines in combination with the use of impure kerosene.

Abstract: A method for beneficiation of magnesite ore wherein the ore is subjected to calcination to decrease the bulk density of the magnesite relative to the gangue. Accordingly, after such calcination, conventional gravimetric separations can be conducted with greatly increased efficiency. When the calcination is conducted in a reducing atmosphere, initially non-magnetic gangue material is converted to a magnetic form and conventional magnetic separation procedures are conducted with enhanced efficiency.