Alumina sols contg. chloride or fluoride - rapidly and controllably prepd. by predigesting alumina to provide part aluminium content

摘要

sol. contg. combined chloride or fluoride and 13-15 wt.% Al is mfrd. by digesting sufficient solid Al2O3 particles to provide 5-25 wt.% of desired Al content in HCl or HF before digesting metallic Al in the selected acid to provide the rest of the desired Al content. The amt. of HCl or HF used for digestion is selected to provide a sol. contg. combined chloride or fluoride in 0.5-2.0 at. ratio with Al. A controlled reaction can be obtained using fine Al particles for rapid reaction rate. Formation of undesirable high molecular wt. sol. polymers is avoided and the sol. has improved homogeneity and reproducibility.