Patent ID: 7820119

Claim:
A system for making ferric chloride with low amount of hydrochloric acid for a water treatment process, the system comprising: a ferric oxide source and a hydrochloric acid source; a reactant batch comprising between about 20 weight percent and 25 weight percent ferric oxide and between about 24 weight percent and 27 weight percent hydrochloric acid of the reactant batch in aqueous solution at a predetermined molar ratio that is stoichiometrically rich in a concentration of ferric oxide relative to a concentration of hydrochloric acid, the ferric oxide and the hydrochloric acid respectively from the ferric oxide source and the hydrochloric acid source and added together to form the reactant batch; a batch reactor in fluid communication with the ferric oxide and hydrochloric acid sources, and receiving the reactant batch the batch reactor having inner side walls and a bottom integral with the inner side walls, the batch reactor having baffles disposed on the inner side walls and a mixer having a rotating shaft and an impeller disposed at the bottom of the reactor, the mixer being configured to mix the reactant batch at an agitation speed between about 60 and 150 revolutions per minute and form a reaction product comprising ferric chloride, unreacted ferric oxide and between about 0.1 and 3 weight percent hydrochloric acid; a scrubber in fluid communication with the batch reactor to receive hydrochloric acid vapors vented from the batch reactor for hydrochloric acid processing; and a filter in fluid communication with the batch reactor for filtering the reaction product.