The oxidation of sulphide minerals

doi:10.1016/S0040-6031(96)03132-2

Thermochimica Acta

Volume 300, Issues 1–2, 15 October 1997, Pages 127-139

https://doi.org/10.1016/S0040-6031(96)03132-2 Get rights and content

Abstract

The literature associated with the thermal behaviour of mineral sulphides has been selectively and critically reviewed. Particular attention has been paid to:

•
• the importance of characterising the starting material, as well as intermediate products
•
• the effect of experimental variables on the thermal analysis results

The various reactions that sulphides can undergo in inert and oxidising atmospheres are presented. Under mild oxidising conditions, such as an air atmosphere and heating rates of 10–20°C min⁻¹, the oxidation occurs as a sequence of reactions usually controlled by oxygen diffusion, although in some situations decomposition of the sulphide with evolution of sulphur can occur. Besides the formation of oxides and sulphates, and the subsequent decomposition of the latter, solid-solid reactions can occur between sulphates and unreacted sulphides. In ternary systems, such as the iron-nickel sulphides, considerable ion diffusion can take place.

Under more vigorous oxidising conditions, such as an oxygen atmosphere with a heating rate in excess of 40°C min⁻¹, some sulphides can be ignited. Under these conditions the relative ignition temperatures of sulphides can be measured, and the effects of variables such as particle size and stoichiometry on the ignition temperature examined.

The oxidation of pyrite is presented as a case study of the effects of experimental variables on the results of thermal analysis. The application of the results of studies to the industrial processing of sulphides of economic importance has been discussed.

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Before leaching, the oxidation of sulfides can expose the wrapped gold, increasing the contact area of gold with the gold leaching agent and, thus, elevating the leaching efficiency of gold. The primary oxidizing techniques for sulfur-bearing refractory gold ores include roasting (LaBrooy et al., 1994; Angelidis and Kydros, 1995; Dunn, 1997), pressure oxidation (Mason, 1990; Thomas, 1991; Melashvili et al., 2015, 2016), chemical oxidation (Bouffard et al., 2006; Li et al., 2006; Constantin and Chirita, 2013), and biological oxidation (Lawrence and Bruynesteyn, 1983; Deng and Liao, 2002; Hol et al., 2010). In recent years, great progress has been achieved in the study of pyrite oxidation pretreatment for refractory gold ores.
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Pyrite, a kind of iron disulphide (FeS2), has been widely used in modern industry for the extraction of elemental sulfur (Yang et al., 2009). Previously published studies reported the decomposition and oxidation of pyrite under different atmospheres, indicating that elemental sulfur and pyrrhotite could be obtained during the thermal decomposition of pyrite in an inert atmosphere (Dunn, 1997; Dunn and Chamberlain, 1997; Boyabat et al., 2004; Hu et al., 2006; Bhargava et al., 2009; Lv et al., 2015). In this study, the generated elemental sulfur was the main ingredient for the preparation of Lime-Sulfur-Synthetic-Solution (LSSS), which can be used to extract gold from gold-bearing sulfides.
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The oxidation of sulphide minerals

Abstract

Thermochim. Acta

Thermochim. Acta

ICTAC News

Thermal Methods of Analysis

Thermogravimetry

Econ. Geology

Metall. Trans.

The effect of stoichiometry on the thermal properties of violarite and pentlandite

J. Therm. Anal.

J. Therm. Anal.

Russian Met. (English translation)

Trans. Met. Soc. AIME

Amer. Mineralogist

J. Therm. Anal.

J. Therm. Anal.

J. Therm. Anal.

J. Amer. Ceram. Soc.

J. Therm. Anal.

Indian J. Chem.

Trans. Indian Inst. Metals

J. Therm. Anal.

J. Therm. Anal.