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- Sun, Zhongxi, et al.
(author)
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Degradation kinetics of ethyl-xanthate as a function of pH in aqueous solution
- 1997
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In: Minerals Engineering. - 0892-6875 .- 1872-9444. ; 10:4, s. 389-400
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Journal article (peer-reviewed)abstract
- 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 pHgt;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.The rate 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.
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- Evertsson, Magnus, 1967, et al.
(author)
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Investigation of Interparticle Breakage as Applied to Cone Crushing
- 1997
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In: Minerals Engineering. - 0892-6875. ; 10, s. 199-214
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Journal article (peer-reviewed)abstract
- The breakage of material in cone type gyratory crushers is traditionally regarded as relying upon single particle breakage. In the last ten years the emphasis has shifted with manufacturers trying to generate higher degrees of interparticle breakage. Increasing the degree of interparticle crushing is claimed to improve crushing efficiency and product shape. The current study uses form conditioned crushing tests (geometry controlled compression) to investigate how multiple particles respond to crushing loads. By variation of test parameters the breakage characteristics of a rock material can be determined and compared to traditional single particle crushing. The selection function, S (probability of crushing a single particle), seems to be related to the ratio between stroke and bed height, s/b, with a second order polynomial in s/b. An analysis of a given crusher chamber gives selection values in the range 0.05
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