Metakaolin (MK) is one of the most sustainable cementitious construction materials, which is derived through a direct heating procedure known as calcination. Calcination process takes place substantially lower temperatures than that required for Portland cement, making it a more environmentally sustainable alternative to traditional cement. This procedure causes the removal of hydroxyl water from the naturally occurring kaolin clay (AlSiO(OH) with MK (AlO·2SiO) as its product.
View Article and Find Full Text PDFThe disposal of mining wastes that contain cyanide are dumped in tailings from gold extraction is a public concern in mining countries such as South Africa. Many studies have shown the potential of microorganisms to degrade cyanide. However, no in-situ exploration, in tailings contaminated with cyanide, of the capability of indigenous microorganisms to act as a natural barrier for cyanide attenuation has been performed.
View Article and Find Full Text PDFCyanide, which remains the preferred chemical used in the gold extraction process, has the potential to be disposed of on goldmine tailings. South Africa has nine goldfields, producing approximately a third of the world's gold to date. The cyanide interacts with metals in the tailings environment, where Prussian blue [Formula: see text] and Turnbull's blue [Formula: see text] are among these.
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