Relating enthalpies of adsorption of thiol collectors and collector mixtures on base metal sulfide minerals to their floatability

J. Taguta, C. T. O’Connor, B. McFadzean

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

In order to recover minerals by flotation, the sub-processes of collector adsorption onto the valuable minerals followed by bubble-particle attachment should occur efficiently. This paper investigates both of these sub-processes for various thiol collectors and their mixtures onto base metal sulfide minerals. The aim of the work was to investigate whether there is a correlation between the strength of the collector interaction with the mineral and the subsequent bubble-particle attachment. The collector-mineral affinity was measured experimentally using an isothermal titration calorimeter in order to determine the molar enthalpy of adsorption for each collector-mineral system. The bubble-particle attachment was measured using a microflotation device which essentially determines the hydrophobicity of the mineral. Sodium ethyl xanthate (SEX) and sodium diethyl dithiocarbamate (DTC) and mixtures thereof were used as collectors with either single minerals or binary mixtures of pyrite and chalcopyrite, respectively. The adsorption enthalpies of the collectors were interpreted with reference to the chemical structure of the collector molecule and showed that the greater the positive inductive effect of the collector, which may be qualitatively related to their pKa, the greater their affinity for the mineral surface. In the microflotation studies, recoveries were strongly related to the alkyl chain length but there was no correlation between the enthalpies of adsorption and the flotation recoveries. When mixtures of collectors were used there was clear evidence of synergistic effects and in the case of DTC/xanthate mixtures it is possible that this synergism is related to a DTC promoted oxidation of xanthate to dixanthogen. When mixtures of pyrite and chalcopyrite were used the flotation recovery and enthalpy of adsorption of SEX onto the individual pyrite particles in the mixture increased substantially compared to the case of pyrite alone. Mechanisms are proposed to interpret these important observations.

Original languageEnglish (US)
Title of host publicationIMPC 2016 - 28th International Mineral Processing Congress
PublisherCanadian Institute of Mining, Metallurgy and Petroleum
ISBN (Electronic)9781926872292
StatePublished - 2016
Externally publishedYes
Event28th International Mineral Processing Congress, IMPC 2016 - Quebec City, Canada
Duration: Sep 11 2016Sep 15 2016

Publication series

NameIMPC 2016 - 28th International Mineral Processing Congress
Volume2016-September

Conference

Conference28th International Mineral Processing Congress, IMPC 2016
Country/TerritoryCanada
CityQuebec City
Period9/11/169/15/16

Bibliographical note

Publisher Copyright:
© 2017 TAPPI Press. All rights reserved.

Keywords

  • Base metal sulfide
  • Bubble-particle interactions
  • Collector mixtures
  • Enthalpy of adsorption
  • Mineral mixtures
  • Surface reactions

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