Block parts for glass-making furnaces

Abstract

Borovichi Refractory Plant JSC has performed a complex of works on manufacturing fireclay block parts for the lower structure of glass-making furnaces. The characteristics of the technology for producing the parts and the process line as well as upgrading technological equipment and guaranteeing product quality are examined. The physical and chemical properties of ShSU-33 and MLS-62 parts and the advantages of such parts over similar products from other manufacturers are presented.Block parts are ordinarily used in the masonry at the bottom of the melting tank of glass-making furnaces [1]. Before cast baddeleito-corundum parts came into use, because of their large size and the small number of seams large aluminosilicate parts provided the required furnace-tank life; now they also impart stability to the bottom structure of the furnace and reliable thermal insulation there.Work on replacing fired fireclay parts with concrete parts is now being performed [2]. It should be noted that unfired low-cement concrete parts must be put into the operating temperature regime correctly because when heated they undergo a continuous series of chemical and phase transformations: dehydration of the cement, a reaction forming calcium hexa-aluminate in the matrix, and interaction of the calcium hexa-aluminate with the aluminosilicate component of the matrix with formation of mullite and a glass phase [3]. In the course of these transformations, stresses accumulate in the parts as a result of volume changes during phase transitions, and these stresses can weaken the parts and even cause them to fail in the masonry. In fired fireclay parts, the formation of the phase composition is completed during firing at the manufacturing plant and remains unchanged during heating and operation of the furnace over the entire run.All concrete parts (fired and unfired) contain refractory cement -calcium aluminates, chemically less resistant to silicate glass, especially at high temperatures, which can result in chemical corrosion and service life reduction.In 2005, because Podol'skogneupor JSC ceased the production of fireclay block parts, the production of these parts was organized at Borovichi Refractory Plant JSC so as not to lose in Russia the production of the refractory products required by glass enterprises.The K-5000 hydraulic press (Fig. 1) and the SM-1500 continuous intense-action mixer manufactured by Tyazhstankogidropress JSC (Novosibirsk) formed the basis for the mixing-forming line. The powerful 5000 ton K-5000 hydraulic press (Germany) is a unique machine, which makes it possible to provide the force required for semi-dry pressing of large parts. Stromizmeritel' JSC (Nizhny Novgorod) manufactures and delivers mass proportioning equipment for the mixer; this equipment is well-known and needs no further consideration. In addition, a sieve was installed in front of the bucket to prevent size-separation of the mass when the bucket is loaded. Two magnetic iron separators were installed in the mass feed line from the mixer into the process...