Use of graphite-containing sludge in the composition of non-stick coatings

Abstract

The importance of a reasonable choice of effective technological solutions in the use of man-made resources is determined by such factors as the presence of large-scale man-madeformations in the region, which  makes them a promising raw material for the development of hightech industries with a reduced negative impact on the environment. Therefore, in this work, we studied the possibility of using graphite-containing sludge from the aspiration system for cleaning gases in the production of cryptocrystalline graphite as part of a self-drying non-stick coating. The elemental composition of graphite-containing sludge is represented by carbon (up to 45 %), sulfur (up to 1.95 %), silicon (up to 13.0 %); phase composition - graphite (up to 44 %), calcite (up to 12.7 %), crystallobalite (up to 1.5 %), pyrite (up to 3.65 %), quartz (up to 19.23 %), clinochlore (up to 17,1 %) and halite (up to 1.56 %). The sludge particle size is 3.64 microns, the total surface is 36 506 cm2/cm3. Replacing graphite with sludge in the coating composition leads to an increase in its density from 1220 to 1750 kg/m3; viscosity from 34 to 105 s; abrasion resistance from 175 to 245 g of sand. The sludge-based coating does not form a casing layer, while the depth of the penetrating layer can reach 6.0–6.5 mm. The results of the study of the value of burn-on on the surface of a gray iron casting showed that replacing graphite with sludge leads to a decrease in the thickness of burn-on on the surface of the casting by 1.5–3.0 times, depending on the thickness of the casting wall.