| 摘要 |
PROBLEM TO BE SOLVED: To produce a hydraulic alumina prolonged in pot life without using a hardening regulator by instantaneously calcining gibbsite under special conditions. SOLUTION: This hydraulic alumina has 8-15wt.% ignition loss, 100-250m<2> /g BET specific surface area, 1-20μm median grain diameter, at least <=50wt.% content of π-alumina and χ-alumina and rehydrating properties of manifesting moisture restoring properties at <=100 deg.C The hydraulic alumina is obtained by introducing gibbsite prepared in the Bayer's process into an instantaneous calcining device and instantaneously calcining the gibbsite while controlling the outlet temperature of a calcining pipe for a hot gas discharged simultaneously with the gibbsite to 350-500 deg.C. |
