Patent ID: 9718712
Date: 2017-08-01
CPC Classifications: C02F

Claim:
1. A method for treating caustic materials comprising the steps of: providing a first caustic solution stream comprising phenolic constituents and naphthenic constituents, the first caustic solution stream having a pH greater than about 7.0; mixing the first caustic solution stream with an acid solution to reduce the pH of the first caustic solution stream to a pH of about 3.5 to about 4.5, thereby chemically transforming the phenolic constituents of the first caustic solution stream to phenolic acids; separating the phenolic acids from the first caustic solution stream to form a first separated caustic solution stream and a phenolic acid stream; further mixing the first separated caustic solution stream with an additional acid solution to reduce the pH of the first caustic solution stream to a pH of about 1.5 to about 2.5, thereby chemically transforming the naphthenic constituents of the first caustic solution stream to naphthenic acids; separating the naphthenic acids from the first separated caustic solution stream to form a naphthenic acid stream and a first remaining caustic solution stream having a pH of from about 1.5 to about 2.5; providing a second caustic solution stream comprising sulfidic constituents, the second caustic solution stream having a pH greater than about 7.0; mixing the first remaining caustic solution stream with the second caustic solution stream to form a combined caustic solution stream, the combined caustic solution stream having a pH that is more neutral than either the first remaining caustic solution or the second caustic solution streams individually; and oxidizing the sulfidic constituents of the combined caustic solution stream.