METHOD OF PREPARING CHROMO-ALUMINO-PHOSPHATE BINDER Russian patent published in 2002 - IPC

FIELD: manufacture of building materials. SUBSTANCE: invention relates to binders suitable for refractory concretes and to form heat-resistant compositions for gluing steels, bronzes, titanium, and molybdenum at working temperatures 1250 to 1500 C, and as component of molding blend in production of casting molds and mold cores. Chromo-alumino-phosphate binder is prepared from 64-66% orthophosphoric acid, chromium trioxide, aluminum hydroxide, and formaldehyde-containing product for reducing Cr(VI) into Cr(III). Reaction medium is prepared by successively dissolving, in indicated orthophosphoric acid, aluminum hydroxide and chromium trioxide. Above-mentioned formaldehyde-containing product is, in particular, urea-formaldehyde concentrate containing 54.5-59.5 % all forms of formaldehyde, including 20-36 % free form, 20-24.5 % urea, and 20-23 % water. Resulting binder contains reduced amount of free formaldehyde, shows elevated resistance to segregation on prolonged storage and improved joining ability. EFFECT: optimized preparation parameters and improved quality of product. 1 tbl