Title: Application of coupled thermostatted columns in civil engineering and for leaching heavy metals of wastes from foundry sands and mining industry

Authors: J. Vite-Torres, A. Diaz-Calva, C. Carreno de Leon, M. Vite-Torres

Addresses: Gerencia de Ciencias Ambientales, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, Col. Escandon, CP 11801, Mexico. Investigaciones Nucleares, Apartado Postal 18-1027, Col. Escandon, CP 11801, Mexico. Investigaciones Nucleares, Apartado Postal 18-1027, Col. Escandon, CP 11801, Mexico. SEPI ESME Instituto Politecnico Nacional, Unidad Profesional ''Adolfo Lopez Mateos'', Departamento de Ingenieria Mecanica, Av. Instituto Politecnico Nacional s/n Edif. 5, tercer piso, cubiculo 23, Col. Lindavista, CP 07738, Mexico

Abstract: For many years, the mining industry at Pachuca Hidalgo, Mexico, has produced silver and gold through a cyanide process. Solid wastes (tailings) of this process have been deposited close to centres of population. Many of the metals in these wastes are dispersed via wind and rain, and can be toxic to flora and fauna. Foundry sands are wastes, produced by the automotive industry, the metallurgy industry and others, which are contaminated with many metals such as Fe, Cr, Zn, Pb, Au Ag, Ti, Ge, Co, As, Al, etc. We have previously patented a process for the extraction of toxic and valuable metals from foundry sands using a thermostatted column. The results of this study indicate that the process and the device could be used for removing heavy metals from tailings. In this research both types of waste (foundry sands and tailings) were leached using four coupled thermostatted columns. The presence of heavy metals in the solid wastes was studied using the ICP-AS technique and scanning electron microscopy, and to study the structure we used X-ray diffraction. After leaching we used the solid wastes (without toxic metals) to produce bricks. The mechanical properties of the bricks were assessed against international standards.

Keywords: bricks; civil engineering; coupled thermostatted columns; foundry sands; heavy metals; leaching; tailings.

DOI: 10.1504/IJEP.2003.003306

International Journal of Environment and Pollution, 2003 Vol.19 No.1, pp.46 - 65

Published online: 13 Dec 2003 *

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