Patent ID: 7645435

Claim:
A sodium carbonate monohydrate process for recovering refined soda ash from waste deposits that contain sodium carbonate and sodium bicarbonate, by combining at least two aqueous streams derived from streams of waste sodium carbonate deposits that contain sodium carbonate and sodium bicarbonate and that contain sodium carbonate in amounts too dilute to be effectively separately recovered by a monohydrate process, comprising: a. proportioning and pretreating the said waste streams in a mix tank to produce a combined feed stream enriched in and containing at least 29% sodium carbonate, and reducing the sodium bicarbonate and sodium sulfate contained in said waste streams to below a concentration of 3.5% sodium bicarbonate and less than about 1.4% of sodium sulfate; and b. introducing said proportioned and pretreated waste streams directly to a monohydrate process to produce the refined soda ash product.