Abstract: A process for purification of coal comprises forming an aqueous leaching solution containing nitric and hydrofluric acid. Impurities are removed by contacting coal having a mesh size not greater than 8 (Tyler Series) with the leaching solution for a period of 15 to 120 minutes at a temperature of 20.degree. to 100.degree. C. During the contacting of coal with leaching solution, a gaseous material such as air can be bubbled therethrough to provide additional mixing action and oxidant material. Thereafter, the solution is removed and the leached coal washed with water.

Abstract: A process for the production of activated carbon from coal comprises contacting the coal with mineral acids to leach impurities therefrom and removing the leached coal from the mineral acids. Activated carbon is produced by calcining the leached coal at a temperature in the range of 550.degree. to 775.degree. C.

Abstract: Aluminum-silicon alloys are formed by bringing a mix containing sources of alumina, silica and carbon to a temperature in the range of 1500.degree. and 1600.degree. C to form silicon carbide and carbon monoxide. The mix containing the silicon carbide is then brought to a temperature in the range of 1600.degree. to 1900.degree. C to form aluminum oxycarbide and carbon monoxide. Thereafter, the mix containing the silicon carbide and aluminum oxycarbide is brought to a temperature in the range of 1950.degree. to 2200.degree. C to produce an aluminum-silicon alloy.

Abstract: A method of producing an aluminum-silicon type alloy from alumina-silica bearing materials comprises providing the silica and alumina bearing materials in a mix having a weight ratio of silica to alumina in the range of 0.5 to 1.1. The method further comprises providing a source of carbonaceous material in the mix and carbothermically reducing it to form the aluminum-silicon alloy.