CERAMIC ARTICLE, RAW MIXTURE AND A METHOD OF CERAMIC ARTICLE MAKING Russian patent published in 1995 - IPC

FIELD: ceramics. SUBSTANCE: ceramic articles were made of the raw mixture consisting of, wt.-% clay 20-79.9; spent bentonite drilling fluid 20.1-80. Spent bentonite drilling fluid is dried up to the moisture 2-3% then mixed with clay up to definite composition mixture preparing. Then blanks were pressed or formed, dried and calcined in tunnel-type furnace, annular kiln or roller-hearth furnace. In tunnel-type furnace roasting is carried out at 950-1000 C for 18-40 hr, in annular kiln at 950-1000 C for 30-55 hr and in roller-hearth furnace at 1020-1080 C for 8-12 hr. Physico-mechanical indices: compression limit strength is 75-300kgs/cm², bending limit strength is 14-44kgs/cm², water absorption is 6-8% not less. EFFECT: enhanced quality of ceramics. 7 cl, 4 tbl