INFLUENCE OF CHROMIUM ELECTROPLATING WASTEWATER SLUDGE ADDITIVE ON THE PROPERTIES OF CLAY BODY

This study focuses on estimating the possibility to use chromium electroplating wastewater sludge (GPN) as an additive to ceramic products. The influence of electroplating sludge addition on the properties of clay body from easily fusible clay was investigated. It was determined that clay sintering with a 5 % GPN sludge additive fired at 900–1025 °C was similar to that of the Girininkai clay. The total shrinkage of this ceramic body, depending on a sample firing temperature and time, is by 1.49–8.72 % less than that of clay body without additives. Water absorption is higher by 0.28–6.63 % than that of the Girininkai clay ceramic body. With increasing the additive concentration, the sintering of clay is getting worse. After firing at 1050 °C for 1 h, a ceramic body with the 10 % GP addition absorbs by 16.30 % more water than the Girininkai clay body does. Chromium ion concentration in the leachate from a ceramic body with 5 % the sludge additive fired at 1000−1050 °C for 4 h is less than the concentration limit to the natural environment. According to the results of clay body sintering and the chromium concentration in the leachate from this ceramic body, galvanic electroplating sludge could be used as an additive to building ceramic manufacturing. DOI: http://dx.doi.org/10.5755/j01.ct.65.1.8714