Microcrystalline magnesium aluminium oxide hydrate - - formed from sodium aluminateand magnesium oxide

摘要

Microcrystalline magnesium aluminium oxide hydrate, for use as a white pigment in the coating industry, is made simply and rapidly by reacting sodium aluminate soln. with MgO suspension. The Mg/Al ratio should be 1:1 to 2:1. The mixt. is refluxed for 4-6 hrs., cooled to ambient temp. NaHCO3 is added if desired, and the prodt. is filtered, washed and dried. Pref. the sodium aluminate is made by dissolving this substance in water at 20-100 degrees C (60-70 degrees C). The pigment is easily espd. from the mixt., has good, non-fading whiteness and does not bloom.