Sodium aluminate recovery from dil. solns. - by evapn. in fluidised bed

摘要

Sodium aluminate is recovered from solns., in which the Na2O content is 45-350 g/l pref. 250-280 g/l. and the molar ratio Na2O:Al2O3 is 1.1:1.8 (pref. 1.1-1.3) by evapn. in a fluidised bed at 250-400 degrees C. Dil solns. contg. 45-180 g Na2O/l are pref. preliminarily conc. to 250-350 g/l NaOH/l. in an evaporator(s), opt. under vacuum. This process is esp. suitable for the recovery of sodium aluminate from dil. solns. such as the washing water from the Bayer process. This process is highly effective and more economical then in the known similar processes. The prod. can be obtd. in the form of powder or granules.