O uso do lodo de estação de tratamento de água e resíduos da indústria de celulose (dregs, grits e lama de cal) na produção de cerâmica vermelha

Abstract

The sludge is an inevitable residue of Water Treatment Plants. Quantities are growing as a consequence of development and expansion of modern society. The usual practice is to discharge it directly into the water without any kind of treatment. This procedure compromises not only the quality of water bodies as also the life of actual and futuregenerations. With crescent restrictive environmental legislation a new posture is being required from the managers of water works for the correct disposition of sludge. In this work the sludge from an industry situated in Belo Oriente (Minas Gerais), that realizes the processof coagulation with aluminum sulfate, is combined with three residues from the recuperation of chemicals of the cellulose industry (dregs, grits and lime mud) and one other from crushing and grinding of granite rock (granite fines) were used as raw material in the formulation ofceramic mass for brick production. This formulation is based on the grain size distribution of the residues and the proportions of calcium, sodium and potassium oxides in the mixtures. The objective is to obtain in the material, after burning, crystalline phases (anorthite, albite, gehlenite, mullite) that confer good mechanical properties. The statistic analysis of the data showed that, although the results do not attend all technological parameters evaluated for the red ceramic in the experimental conditions, the mixture B (50% sludge + 30% de sludge + 20% de granite fines), C (50% sludge + 30% sludge + 12% de granite fines + 8% dregs), D(70% sludge + 30% dregs) e F (65% de sludge + 20% dregs + 15% granite fines), at temperatures of 850 and 950 oC should be tested in the ceramic industry at pilot scale specially considering the attainment of reference values of ignition loss, firing shrinkage and flexural strength..