Refractory Formulations Made of Different Wastes and Natural Sub-Products

Abstract

This work describes studies on the preliminary processing of calcium aluminate mortars based on several industrial wastes and natural sub-products. The starting materials are sludges (generated in Al-anodising and surface coating industrial processes, potable water filtration/cleaning operations and cutting process of natural marble rocks), and foundry sands. These materials are all classified as non-hazardous but high daily-produced amounts involve high transportation costs for disposal. Reusing alternatives should be sought.The characterization of the waste materials is reported, including physical and chemical parameters and thermal behaviour. Several powder mixtures were prepared and fired at different temperatures. Compositional changes were assessed by XRD and powder density, average particle size, and specific surface area, were determined. The compression and flexural strengths of the corresponding pressed and sintered samples are also given.

Extrusion and property characterisation of waste-based ceramic formulations

“…9 Even the basic activity of water filtration/clarification for human consumption generates a significant volume of sludge. 12 In general, the composition of a specific waste product reflects its source, showing various levels of contamination according to the processing/conditioning methods. In terms of chemical composition, the dominant oxide in the great majority of waste materials is silica (SiO 2 ), closely followed by alumina and lime (Al 2 O 3 , CaO), and finally by fluxing oxides (alkalies and iron).…”

“…However, there might be reusing or recycling alternatives that should be investigated and eventually implemented. [1][2][3][4][5][6][7][8][9][10] The extraction of mineral resources from the ground and their transformation are good examples of this scenario. 11 Industrial processes like aluminium anodising and powder surface coating, are highly water consuming and, in the end, a huge flow of wastewater has to be treated, leading to the formation of high amounts of sludge.…”

Fraguado de cementos basados en residuos estimado por espectroscopia de impedancia y medidas en temperatura

“…The foundry sand was milled and sieved through 75 µm; the other materials were used in the as-received condition. Their full characterisation is detailed elsewhere (21)(22)(23). The average chemical composition was determined by X-ray fluorescence (XRF, Philips X'UNIQUE II), and Figure 1 shows their location in the SiO 2 -Al 2 O 3 -CaO ternary composition diagram.…”

Caracterização de Resíduo Sólido de ETE da Indústria Cerâmica de Revestimento

“…Toda a produção e transformação de materiais industriais, seja em pequena ou grande escala, gera resíduos que muitas vezes não têm disposição ecologicamente correta ou adequada reutilização 2 . Em alguns casos, estes resíduos podem ser utilizados como produtos secundários ou podem ser reutilizados diretamente como matérias-primas em outros processos industriais (subprodutos), aumentando seu valor e, consequentemente, trazendo benefício socioambiental 3,4 . O desenvolvimento de práticas de reciclagem tem se tornado expressiva em todo o mundo.…”

“…Desta forma, a reciclagem desse resíduo pode desempenhar um importante papel na economia de matérias-primas brutas e na diminuição da poluição ambiental causada por estas indústrias 4,7 . Isso pode ser conseguido por meio da substituição de uma ou mais matérias-primas da composição original por lodo cerâmico, respeitando-se as características tecnológicas do processo e as propriedades do produto 8 .…”