M Ghiani

Heavy metal immobilization in the mining-contaminated soils using various industrial wastes☆

The remediation of contaminated sites, legacies of past industrial activities, requires more or less complex and costly measures depending on the nature and extent of contamination, the environmental protection legislation currently in force, the anticipated future use and the commercial value of the land. Remedial action involves implementing techniques capable of removing or containing the contaminants to prevent them from migrating to surrounding areas. Here we explore the possibility of using red muds, bauxite ore processing waste, and/or fly ash produced by coal fired power stations for immobilizing the heavy metals contained in severely contaminated soils. The results of laboratory column leaching demonstrate that relatively small additions of fly ash or red muds, or a combination of the two, to the contaminated soils drastically reduces the heavy metal content in the effluent.

Ore and Coal Processing with the Turbocharger Electrostatic Separator

The features of the Turbocharger pilot plant set up at the Department’s laboratories are illustrated. The separation results are presented for different operating conditions, such as nature and temperature of the target surface, rotor spinning velocity, feed rate, electrostatic field intensity, electrode geometry and position of selection splitters. The effect of particle size is also underlined. Expected improvements with apparatus development and technique refinement are also pointed out. The problems connected with the commercial application of the system are dealt with in the conclusions.

Beneficiation of low grade feldspar ores for the ceramics industry

Abstract The decline in the production of single fired ceramic tiles has made it difficult to find a market for the poorer quality feldspars. Producers are thus faced with the problem of improving the quality of their products also with a view to increasing profit margins. In this context, the paper addresses the problems involved in enhancing the value of some raw materials currently sold to the less profitable markets or considered as waste material. Three different cases have been examined and the results of experimental studies have demonstrated the feasibility of applying basic mineral processing techniques such as magnetic separation, surface attrition and selective flotation for obtaining concentrates with high added value and as such more readily marketable. The processing flow sheets, usually a combination of the above techniques, become more complex and more expensive, the higher the quality desired of the final product.