The usage of iron-containing sludge wastes in ceramic bricks production

Abstract

The article considers the opportunity of utilizing sludge wastes, generated at the vanadic pentoxide and ferrovanadium alloys production cycle, in walling ceramics production. The considered materials belong to polymineral systems in their chemical and mineral composition, and contain the crystalline phases – calcium carbonate and sulphate, and the iron-containing components – hematite, wustite, the sulphate form of hydrated calcium sulfoferrite and the residual amount of lime. The metal oxides are contained in the amorphized state. The ferriferrous concentrate sludge, added to the raw mix, due to the high content of iron compounds in it, demonstrates mineralizing and fluxing properties. At baking the raw mix, containing limestone-gypseous composition, the processes of intensive release of such gases as CO2 and water vapor is observed, as the products of carbonate and sulphate components. The adding of sludge materials to the raw mix composition results in the alteration of the color of the obtained samples from red-brown to black-brown. The adding of sludge to the raw charge of ceramic brick in amount of 3–5% of weight doesn’t impair its physical and mechanical characteristics. The increase of its content to 30% causes the porous structure formation and reduces the density and strength characteristics of materials. The obtained wall ceramic products can be used as structural and heat-insulating materials for making enclosing structures and interior partitions.