Briquetting of porous alumina-containing materials with organic binders

Abstract

Waste from corundum production in the form of porous alumina sludge is a promising material for providing ferrous metallurgy with cheap alumina-containing slag-formers. However, the direct feeding of the pulverized materials to the steelmaking furnace generally results in a significant carryover of such materials with waste gases. This paper considers the possibility of making briquettes from porous sludge of corundum production by cold briquetting using various common binders (molasses, cement, powder based on polyacrylamide, emulsion based on polyvinyl acetate). A comparison of the features of cold briquetting of powdered porous materials (slimes from the production of electrocorundum) and dispersed crystalline materials (fines of chrome ore) was made. Experiments were carried out to determine the impact strength of briquettes on different binder (“cold” strength) and tests to determine the “hot” strength (by the “thermal shock” test method). The authors have determined the consumption of the binder required to obtain satisfactory characteristics of briquettes from corundum slimes and from chrome ore fines. A technique has been developed and a mechanism for the binding of particles of loose and crystalline materials has been determined during briquetting using polyacrylamide powder. The destruction of a briquette of loose materials occurs mainly along the grains of the most porous material, and briquettes of crystalline materials are destroyed along the boundaries of the grains glued with a binder. For porous materials, the binder consumption increases more than twice as compared to briquetting on the same binder crystalline bodies of a fine fraction, and the binder must necessarily impregnate the entire volume of the porous material.