Recovery of cobalt and manganese from waste streams of the petrochemical industry on the example of terephthalic acid production process

A 1% soln. of (COOH)(2) in 90% MeCOOH was added to a 90% MeCOOH soln. contg. Co and Mn ions at concns. of 500 and 300 ppm, resp., and impurities typical of the oxidn. of p-xylene to C6H4(COOH)2 (BzOH, HBr and Na ions) in amts. simulating the mother liquor compn. of a real industrial process. After mixing, the Co and Mn contents of the decanted liq. were detd. by AAS. Presence of impurities had no neg. impact on the ppt. formation. The presence of solid C6H4(COOH)(2) in the reaction mixt. had a pos. impact on the catalyst recovery process. Oxalates formed agglomerates on the surface of the solid C6H4(COOH)(2) which facilitated the sepn. of the ppt. from the mother liquor. The pptn. with (COOH)(2) is an efficient recovery method of spend Co(II) and Mn(II) homogeneous catalysts.