Matrix and pH effects on the degradation kinetics of xanthates in mining waters

Determination of optimal pH conditions for a xanthate solution representative of a real matrix in an industrial setting (such as a flotation tank or a tailings pond) was researched to help ensure mill efficiency in mines. The primary method for analysis was the use of headspace GC-MS. Aqueous samples of xanthates in basic solutions without minerals were tested for degradation by testing for the generation of carbon disulfide (CS2). Potassium isopropyl xanthate (PIPX) and potassium amyl xanthate (PAX) were primarily studied and rate constants were compared to determine optimal pH conditions for the slowest degradation of individual xanthates. The rate constant for 110.6 ppm PIPX was found to be 5.79 x 10-5 h-1 at pH 7.73; at the same pH, the rate constant was found to be 3.91 x 10-6 h-1 for 1075.2 ppm. The rate constant for PAX was found to be 5.43 x 10-5 h-1 at pH 9.08, 1.23 x 10-5 h-1 at pH 9.26, 8.12 x 10-6 h 1 at pH 9.34, and 4.36 x 10-5 h-1 at pH 9.48.Supervisor Dr. Kingsley DonkorXanthateDecompositionRateCarbon disulfideGas chromatography-mass spectrometr