Patent ID: 10723633

Abstract:
A process is provided for recovering a heavy metal from a waste stream resulting from a process for producing aromatic carboxylic acid by liquid-phase oxidation of an aromatic feedstock compound in the presence of a heavy metal catalyst. The process comprises: (a) producing a carbonate salt precipitate of the heavy metal by adding a source of metal ions and carbonate or bicarbonate ions into the waste stream; (b) separating the precipitate from the waste stream; (c) washing the precipitate with an alkali solution having metal ions therein, wherein at least a portion of the metal ions in the alkali solution are the same as at least a portion of metal ions in the source of metal ions and carbonate or bicarbonate ions; and, (d) recovering the washed precipitate wherein the washed precipitate comprises the heavy metal ions. In one embodiment, the aromatic carboxylic acid comprises terephthalic acid.