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Valorization of Foundry Sand in Clay Bricks at Industrial Scale

Environmental Behavior of Clay−Sand Mixtures


Address correspondence to:
Ana Andrés
Department of Chemical Engineering
 and Inorganic Chemistry
University of Cantabria
Avda. Los Castros s/n
39005 Santander, Spain


In this article, foundry sand as waste material has been valorized in ceramic brick manufacturing at industrial scale. The employment of a waste coming from one industry as an input for another is one of the key concepts of industrial ecology. To study the environmental behavior of the ceramic bodies in different life cycle stages, three leaching tests have been developed. We used an EN 12457 equilibrium leaching test with distilled water and a Wastewater Technology Centre acid neutralization capacity (WTC-ANC) leaching test with different acidic leachates to carry out the environmental evaluation under different granular scenarios to ascertain the possibilities of the reuse or disposal of this granular material at the end of its useful life (end-of-life stage). Finally, we used a NEN 7345 diffusion leaching test for construction materials, with the aim of studying the environmental assessment at the use stage. Regulated pollutants in both stages have been evaluated. Furthermore, other soluble salts have been analyzed because they are closely related to the efflorescence phenomenon in bricks. Results indicate that core and green sand from the foundry industry can be used to replace clay content in construction materials, and that these foundry-sand-based ceramics improve some soluble salt results. Despite this fact, at the end-of-life stage in an inert waste landfill, lead, arsenic and chromium can be an environmental problem, both for commercial bricks and for foundry-sand-based bricks. This work can contribute to the determination of viability of sustainable processes of brick manufacturing that use foundry wastes as raw materials.

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