Development of environmentally safe acid-resistant ceramics using heavy metals containing waste

Abstract

The paper presents research results concerning charge composition development to produce environmentally safe acid-resistant ceramics on the basis of low-plastic clay of the Vladimir region possessing self-glazing effect. 5 wt. % boric acid, 5 wt. % lanthanum oxide and up to 5 wt. % electroplating sludge have been introduced into the charge composition as functional additives. Boric acid serves as a flux and a source acid-resistant and heat-resistant vitreous phase based on borosilicates, but compositions contained in the electroplating sludge are decomposed in the process of ceramics firing causing the formation of calcium oxide and heavy metal oxides, which additionally increase material acid-resistance and heat-resistance like lanthanum oxide. To receive the developed material, semidry pressing technology has been applied under the charge forming moisture of 8 wt. %, specific pressure of 15 МPа and one-stage firing at max temperature of 1050 °C. The research presents the testing results of ceramics principal operating properties and environmental safety. The developed material can be used in clinker and acid-resistant bricks and tiles production for masonry and tiling in aggressive environment like buildings foundations and bases, premises with high moisture, as well as in sewerage systems, chimneys and ventilation ducts.