Devising technology for utilizing water treatment waste to produce ceramic building materials

Based on the modern ideas about environmental protection, this paper reports a study into the utilization of water-treated waste from heavy metals (using copper(II) compounds as an example) for the manufacture of ceramic building materials. The examined clay minerals from local deposits and the optimal conditions for their heat treatment (at 1,100 °C) have been proposed for the sorption removal of pollutants of inorganic origin from wastewater. The use of wastewater after its treatment makes it possible to address several tasks at the same time: to protect the environment from pollution by technological wastewater, as well as to reuse wastewater in order to resolve the issue of water scarcity. Ceramic building materials were manufactured based on water purification waste (in the amount of 5 %) and clay raw materials. Their structural-mechanical and physicochemical characteristics have been comprehensively studied. Sintering processes begin at lower temperatures, which is why, with an increase in the annealing temperature to 1,000 °C and higher, their strength rapidly decreases. In the temperature range of 600‒1,100 °C, there are possibilities to apply ceramic technology to immobilize heavy metals in ceramic matrices. The prospect of utilizing water purification waste in the technological process of manufacturing inorganic ceramic materials has been shown. The safety of the building materials, manufactured by leaching pollutants from the ceramic samples using various aggressive environments (leaching to 6.4 %, 0.083 mg·cm2/day) has been investigated. The high strength and degree of the copper ion fixation in the structure of polymineral clay have been confirmed while secondary environmental pollution is almost absen