Production of facing brick by plasma treatment using raw material from technogenic deposits

Abstract

The production of facing brick by plasma treatment combined with technological operations of softening roasting and spray-coating of decorative material based on technogenic raw material is examined. A unified nomenclature of quality indicators for wall (facing) ceramic is developed.In housing construction, a great deal of importance is now placed on the exterior finishing of buildings and the longevity and quality of the facing materials and their architectural expressivity. Plasma treatment of the facing surface of structural materials is one of the most effective treatments, since it conserves resources and energy. Plasma technology is ecologically clean because it uses argon gas to form the plasma. The high plasma temperatures (7000 -10,000 K) greatly intensify the processes leading to the formation and accumulation of a glass phase in the surface layers of the ceramic being treated, including the facing surface of structural materials. As a result, the treatment time is shorter than for conventional technology.The present article presents the results of investigations of glazing on wall ceramic using powders based on raw material from technogenic deposits. Wastes from enrichment of KMA iron quartz, from claydite production, and from the production of ceramic sanitary ware were used for glazing. The chemical composition of the waste is presented in Table 1.A number of investigations have shown that powders with grain size 10 -250 mm are optimal for plasma spraying [1,2]. We used the 60 -250 mm fraction of KMA wastes for plasma spraying. Other production wastes were first milled in ball mills with uralite balls and sieved in sieves with cell sizes corresponding to plasma spraying technology.The UPU-8M serially produced plasmatron was used for plasma treatment. The operational parameters of the plasmatron were as follows: working voltage 30 -32 V and current strength 350 -450 A. Argon serves as the plasma form the gas; its flow rate was 2.5 m 3 /h at pressure 0.25 MPa. The flow rate of the water cooling the GN-5r plasma burner was 10 -12 liters/min. The Saha equation was use to calculate the temperature of the plasma flame [3]. The calculations show that the mass-average temperature of the plasma flame with current strength 350 -450 A and argon flow rate 2.5 m 3 /h is 7800 -8600 K.

Plasma Technologies in Construction Industry

“…Protective-Decorative Coatings for Silicate Materials. Previous research has demonstrated that when plasma flow contacts with the surface of silicate building materials, the formation of a layered structure occurs [16][17][18]. Another authors [19,20] presented the results of calculations for the temperature field distribution over the section of a treated product.…”

Chipboards with Plasma Protective Decorative Coatings

“…The most durable protective decorative coatings on wood materials are vitreous coats. Today, the plasma technology is effective, which allows to obtain protective decorative coatings without heating the entire substrate material to high temperatures [6][7][8][9][10]. Coatings obtained by plasma melting and spraying technology are of high quality and exceed the service life of coatings obtained by traditional technologies.…”