Using Gold-Silver Tailings on the Elaboration of Ceramic Foams

Ceramic foams were elaborated from gold-silver tailings and sodium silicates as foaming agent. The effects of the temperature and sintering time in a range of 850-880 degrees C and 30-45 min, respectively, were evaluated. The foams obtained were characterized determining their apparent density, porosity percentage, volumetric expansion, mean pore size, and mechanical strength. The results show that the sintering time had a greater impact on the properties of the foamed material than the sintering temperature, since it was observed that the characteristics of the studied foams as a function of time had a bigger variation. In addition, an almost direct linear trend with porosity, pore diameter, volumetric expansion, and an inverse linear trend with apparent density and mechanical strength was observed. The ceramic foams obtained in the investigation achieved commercial properties at certain conditions, showing uniform pore distribution, apparent densities lower than 1.0 ton/m(3), pore size lower than 1.0 mm, and mechanical strength greater than 0.4 MPa. Regarding these features, the parameters that achieved the best characteristics of ceramic foams from gold-silver tailings were obtained at temperatures of 850 oC and 860 oC and sintering times from 45 and 35 min, respectively.