Manufacturing of ceramic products using calamine hydrometallurgical processing wastes

Because of the physical, chemical and environmental risks related to industrial wastes and the high consumption of finite natural resources in the construction industry, this paper presents an ecological and sustainable way to manufacture ceramic products using calamine hydrometallurgical processing wastes. This process generates a by-product called herein calamine process tailings (CPMT). Moreover, a sample of treated calamine process tailings (TCPMT) with low amounts of lead was also studied. The aim of this study is to characterize both wastes in order to assess the feasibility of their reuse potential as ceramic alternative materials. The effect of firing temperature on the chemical, mineralogical, environmental behaviors and the physical and mechanical properties of ceramic samples as well as the characterization of the fumes released during firing process are assessed. The results showed that increasing firing temperature enhances the flexural strength of ceramic samples and decreases their open porosity and water absorption. The TCPMT ceramic samples showed very different physical and mechanical properties in comparison with those made with CPMT. These latter samples present high flexural strength values and very low level of water absorption when fired at 1050 °C. This difference might be attributed to high amounts of glassy phase produced in CPMT fired samples. Moreover, the amount of leached metals is reduced significantly after the thermal treatment. However, arsenic, which was in a non-leachable form in the green samples, was found to be leached when tailings are fired. The scanning electron microscopy analysis (SEM-EDS) of condensed fumes evolved during the thermal treatment shows that lead is slightly volatilized.