Abstract: Incorporate the attapulgite and the system of Ca(OH)_2-H_2O-CO_2, the composite powder of attapulgite modified by calcium carbonate used the method of heterogeneous nucleation were prepared. The whiteness, distribution of particle size, the phase constitution and the microscopic pattern were tested and analysed.The results show that the whiteness of attapulgite has raised from 71.13 to 93.37, the average particle size D90 decreases rapidly from 244.620 μm to 22.091 μm and the size of calcium carbonate particle is 30-40 nm. The formation mechanics of composite powder were discussed.

Key words: modifying%attapulgite%composite powder%whiteness%size distribution