Process for continuous production of aqueous basic aluminum salt solutions

Claim 1

A process for continuously producing a basic aluminum salt comprising passing (A) a slurry consisting of (1) an alumina selected from the group consisting of aluminum hydroxide, an alumina-containing mineral and a mixture thereof, and (2) a mineral acid selected from the group consisting of hydrochloric acid and nitric acid, or (B) a slurry resulting from the preliminary reaction of said slurry at a temperature of from normal temperature to the boiling point of an aqueous basic aluminum salt solution, through an indirectly heated tubular reactor maintained at a temperature of at least about 120°C at a flow rate such that solid material in the slurry is not settled, and then passing the slurry of basic aluminum salt of low basicity synthesized in the tubular reactor, said slurry containing unreacted alumina particles, through a holding treatment device having a larger inner diameter than said tubular reactor, the holding treatment device being indirectly heated and maintained at a temperature above the boiling point of the aqueous basic aluminum salt solution, at a flow rate lower than the flow rate at the feeding part of said tubular reactor and near the suspension limit rate to prevent unreacted alumina particles in the slurry from settling, thereby additionally dissolving the unreacted alumina contained in the slurry and obtaining a basic aluminum salt of a basicity higher than that of the salt obtained from said tubular reactor.