EFFECTS OF ADDITIVES ON PRECIPITATION OF SODIUM ALUMINATE SOLUTION AND SUPER-FINE ALUMINUM HYDROXIDE MORPHOLOGY

摘要

Due to its flame retardence and better appearance, super-fine aluminum hydroxide has been used as filler for plastic, rubber and synthetic marble. As filler, the particle size and the shape of super-fine aluminum hydroxide are important properties. In order to control the particle shape, the effects of precipitation temperature, additives and the amount of additives on the precipitation ratio and the crystal morphology are investigated in this paper. The experimental results show that the precipitation temperature and the organic additives can affect the precipitation ratio and the crystal morphology. Some carboxy-containing additives can change the particle shape effectively. The mechanism of additives on the crystal growth of aluminum hydroxide is analyzed according to the experimental results. It is concluded that the crystal growth can be affected by the additives absorbed on the crystal surface and by changing surface property of the seeds.