Self-heating activation energy and specific heat capacity of sulphide mixtures at low temperature

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• 作者：Barnabe Ngabe ; James A. Finch
• 关键词：Mixtures of sulphide minerals ; Activation energy ; Specific heat capacity ; Self-heating apparatus
• 刊名：Minerals Engineering
• 出版年：January, 2014
• 年：2014
• 卷：55
• 期：Complete
• 页码：154-161
• 全文大小：1400 K

文摘

Energy of activation (E_a) and specific heat capacity (C_p) for mixtures of sulphide minerals that on their own do not self-heat (SH), sphalerite/pyrite, pyrite/galena, chalcopyrite/galena and sphalerite/galena, were determined using a self-heating apparatus at temperatures below 100 掳C in the presence of moisture. The mixtures all gave E_a ranging from 22.0 to 27.8 kJ mol^鈭?, similar to the range reported for Ni- and Cu-concentrates. The E_a is close to that for partial oxidation of H₂S which adds to the contention that the partial oxidation of H₂S contributes to SH of sulphides at low temperature. The C_p values ranged from 0.152 to 1.071 JK^鈭? g^鈭? as temperature rose from 50 掳C to 80 掳C, similar to the reported findings on Ni- and Cu-concentrates. The role of galvanic interaction in promoting SH is tested by examining correlations with the rest potential difference of the sulphides in the mixture.