The degradation kinetics of ethyl-xanthate as a function of pH in aqueous solution

Xanthate degradation kinetics plays an important role in sulfide mineral flotation and in the treatment of flotation tailings. Increasing environmental concern about consequences of flotation tailings makes this information even more important. In this paper, the degradation kinetics of xanthate in homogeneous solution as a function of pH at 5°C, 20°C and 40°C is systematically studied by UV-Visible spectrophotometric measurements. The results indicate that the degradation of ethyl xanthate is rapidly increased with decreasing pH at pH < 7. At pH 7–8, the maximum half-life of the xanthate appears. The degradation was faster at pH 9–10, but at pH > 10 the half-lives of xanthate once again increase. The investigations are also extended to different media other than pure water, such as, 0.1 M NaClO4, 0.1 M NaNO3, 0.1 M NaCl as well as in the supernatants of flotation tailings of sulfide minerals. te constants of xanthate degradation are calculated and presented together with half-lives and activation energies of xanthate degradation. The degradation products and reaction mechanisms are discussed based on experimental results.