Abstract: The operation of mineral wool cupolas is improved in several respects and a waste material is efficiently disposed of by using spent pot lining from electrolytic aluminum reduction vessels in the mineral wool cupolas as a partial or complete replacement for coke. The spent pot lining is impregnated with a cryolytic type slag material which aids in both reducing the reactivity of an already unreactive graphitic material such that it burns low in the cupola with desirable thermal results and also prevents the formation of siliceous build-up in the cupola hearth areas. Several variations of cryolytic impregnated carbonaceous materials having the desirable effect of the invention are possible and described.

Abstract: A process for producing mineral wool having a chemical composition comprised of between about 50 and 70 weight percent silica plus alumina, about 20 and 35 weight percent lime plug magnesia and about 5 and 15 weight percent iron oxides is described.The process includes feeding a first particulate waste material having a particle size of 100 weight percent -200 mesh and containing organic combustibles having heating values of about 10 mega J per kilogram of slag and inorganic non-combustibles, a second particulate waste material having a particle size of 100 weight percent -200 mesh and containing fluxstone, and preheated air at a velocity of between about 30 meters to 60 meters per second at a temperature of about 500.degree. C. into a high temperature cyclone-like furnace. The combustibles are substantially instantaneously burned and the non-combustibles and the fluxstone are melted and reacted to form a molten slag which can be fiberized into mineral wool.

Abstract: A method for treating a water slurry of granulated blast furnace slag containing particles of granulated slag having a size consist of about 0.635 centimeter .times. 0 (1/4 inch by 0) wherein a size separation of the particles is made at about 100 sieve. The sink fraction i.e. coarse particles larger than 100 mesh are partially dewatered and thermally dried prior to being comminuted with raw materials to make portland blast furnace slag cement. The float fraction i.e. fine particles smaller than 100 mesh can be used as is or partially dried prior to being used as an additive or extender for a cementitious material in the production of concrete products.