The usage of water conditioning sludge from heat power industry enterprises in wall ceramics production

Abstract

Abstract The paper considers the ecological problems of water conditioning systems at heat power industry facilities. It is noted that the stable operation of water-heating equipment is provided with the quality of feed water. Various water-soluble salts, which can incrust the inner walls of boilers or pipelines, are removed from the natural water. For desalination of natural water the physical-chemical methods are mostly used. The by-product of desalination or chemical water-conditioning systems is the sludge waste. This work presents the results of using chemical water conditioning sludge from JSC Verofarm in the raw charge for wall ceramics production. The sludge is a finely-divided powder, the mineral composition of which is presented with calcium and magnesium carbonates, brucite and iron compounds, which make the sludge pink. It has been determined that the baking of sludge-containing ceramic samples at temperature 1000°C results in dissociation of calcium and magnesium carbonates with the formation of gaseous products H2O and CO2, which make the structure of ceramic materials porous. The presence of iron compounds in the raw charge promotes the formation of low-temperature silicate melt, which intensifies the baking process of ceramic samples. The optimal sludge content in the charge that doesn’t reduce the strength characteristics of wall ceramics is 10%. Such sludge content forms the liquid phase on the surface of the raw mix’s particles, which solidifies the forming pores. The increase of sludge content up to 20% intensifies gas generation; the amount of the formed liquid phase is not sufficient, which increases porosity and reduces the density and strength of ceramic materials. At that, the engobe layer is formed on the surface of the obtained wall ceramics samples. The wall ceramics products, obtained with the use of chemical water conditioning sludge, can be used as structural heat-insulation materials in making building envelopes or interior partitions.