Reduction in alpha-transformation temperature of gibbsite and boehmite by powder mixing with seed

Addition of fine alpha -alumina powder as a seed by up to 50 wt% to a gibbs ite (Al(OH)(3)) powder sample enables it to reduce its alpha -transformatio n temperature from about 1360 to 1090 degreesC. Intensive mixing of the sam ple with 50 wt% seed using a planetary mill lessens the alpha -transformati on temperature further down to around 910 degreesC. A similar trend can be seen in the boehmite sample. The intensive mixing (grinding) of these sampl es by the planetary mill is accompanied with their size reduction, dispersi ng fine particles that play a significant role to reduce the cr-transformat ion temperature in the calcination stage.