MIXTURE FOR MANUFACTURING FIRECLAY ARTICLES AND METHOD OF PREPARATION OF REFRACTORIES Russian patent published in 2000 - IPC

FIELD: refractory industry. SUBSTANCE: mixture may be used in preparation of fireclay (mullite-siliceous) refractories of various applications, particularly, for lining of blast-furnace members, casting ladles and other units by method of semidry pressing with use of clays. The mixture includes fireclay powder from low-plastic clays, for instance, clays of arkalyk composition. In this case, clay additionally contains caustic soda with the following ratio of components, wt.%: refractory clay, 17-23; caustic soda, 0.2-0.5; lignosulfonate, 0.1-0.4; fireclay, the balance. In some versions of the invention mixture may additionally contain alumina. Additionally introduced into mixture may be dust from electrostatic precipitator of rotary furnaces of fireclay calcination in amount of 3-16% of mixture weight. Method of manufacture of refractory articles includes preparation of the mixture with wetting of mixture with slip having density of 1.4-1.6 g/cu.cm and subsequent mixing with binding clay, molding of articles, their drying and firing. Molding of mixture is carried out with delay (pause) for 3-4 s of press punch stroke in position of maximum application of force to molded mixture. Raw materials are fired at temperature of 1400-1450 C for 6-12 h (depending on speed of motion of wagons in furnace) to form in ready articles of at least 55 wt.% of mullite (3 Al₂O₃ . 2 SiO₂). EFFECT: higher resistance to heat of refractory lining with use of low-plastic, for instance, arkalyk clays and extended raw material base of alumosilicate refractories. 5 cl, 6 tbl, 1 ex