The use of tannery wastewater in the manufacture of clay bricks

摘要

Tannery wastewater contains a lot of harmful ions, mainly Chromium cations as well as sulfate and chloride anions. In the present paper, it is proposed to use this effluent water in forming clay bricks. The maximum plasticity of clay - water mixtures was reached at 50% wastewater addition. The following properties for samples fired at 1000℃ for two hours were tested in accordance with ASTM, as function of the percent sand addition : linear shrinkage, water absorption, porosity and bulk density. Also, the crushing strength and MOR of the fired samples were determined as function of sand level. Chemical and mineralogical analyses were performed on the green and fired samples. It was found that about 72% of the total chromium was retained in the fired products and that the prepared fired samples consisting of 100 parts clay, 20 parts sand and 50% wastewater, fired for two hours at 1000℃ gave sound bricks compatible with standards, while assisting in pollution abatement.