Ceramic products obtained from rock wastes

Abstract

Residue powders resulting from cutting and machining operations in slate quarries were processed by a press and sintering route to manufacture ceramic products such as flooring and roofing tiles. The first part of this work consisted of a laboratory study carried out by uniaxially pressing the powders to shape and sintering in air using a muffle type furnace. A plan of sintering experiments was followed in order to evaluate the effect of some processing parameters: particle size distribution of the rock waste powders, compacting pressure and sintering cycle (heating and cooling rates, sintering temperature). The sintering tests have shown that the density of the sintered specimens increased gradually up to 1150-1170 • C and then started decreasing. The second stage of this study was carried out at an industrial scale. Since particle size of the raw material was found to be an important parameter, atomisation was used to homogenise the particle dimensions and ensure proper feeding of the pressing systems. Moreover, atomisation is the best way to treat very fine wastes, both for economical and technical reasons. Tiles with the dimensions 200 mm × 100 mm × 7 mm were then uniaxially pressed at 40 MPa and subsequently sintered at temperatures close to 1150 • C. The properties of the products obtained are suitable for flooring tiles.

A pot experiment with mixtures of slate processing fines and compost

“…Only in the mining area of Valdeorras, situated in the South-East of Galicia, the annual production of these slate processing fines (SPF) may be around 120,000 t (Álvarez et al, 2000). By now this material is not recovered, although some potential uses of SPF have been defined, including the manufacture of cement, production of asphalt, as insulator of walls and as arid aggregates (Catarino et al, 2003). Also, slate waste can be suitable for its use as raw materials for ceramic tiles (Campos et al, 2004).…”

Novel mullite-based ceramics manufactured from inorganic wastes

“…In recent years, some attempts have been made to sinter both slate powder wastes (Vieira et al, 1999Catarino et al, 2003;Souza and Mansur, 2004;Campos et al, 2004) and slate-alumina mixtures (Martins et al, 2002(Martins et al, , 2004. However, the sintering mechanism is far from being well understood.…”

Utilização do resíduo do beneficiamento do caulim na produção de blocos e telhas cerâmicos

“…Recentemente, considerável esforço vem sendo dedicado aos estudos e pesquisas visando à reutilização e aplicação segura dos resíduos originados das indústrias de mineração e beneficiamento mineral [3,[6][7][8][9][10][11][12][13][14][15]. A maioria desses estudos mencionou que os resíduos podem ser considerados importantes recursos minerais secundários.…”