Journal of Sustainable Metallurgy

, Volume 5, Issue 2, pp 210–218 | Cite as

Evaluation of Oxidation Reaction of Copper Concentrate Mixed with Silica Sand by Hot-Thermocouple Method

  • Hiromichi TakebeEmail author
  • Yusuke Takahashi
  • Takahiko Okura
Research Article


The hot-thermocouple method was applied to observe the oxidation reaction of a copper concentrate/silica sand mixture and the separation process of sulfide matte/oxide slag melts. The powder sample (0.3–0.4 mg), attached to a Pt–13%Rh/Pt thermocouple, was heated rapidly up to ≥ 1250 °C in Ar gas with the aid of an exothermic reaction of the chalcopyrite due to the introduction of oxidizing gas flow via a needle located near the sample. The sample was a mixture of Cu concentrate/silica sand with an initial Fe/SiO2 mass ratio of 2.0. The reaction processes were monitored by a charge-coupled device through the microscope and recorded by a personal computer. The hot-thermocouple method revealed chalcopyrite ignition with oxygen flow for optimized conditions (temperature of the sample raised rapidly within 1 s up to ≥ 1300 °C). Then, sulfide matte melt spread along the Pt–13%Rh/Pt thermocouple wire and sulfide droplets were isolated inside the oxide slag melt held between the thermocouple wires. The rapid temperature change of the sample within 2 s was evaluated using a previously obtained relation between the temperature and sample color for fayalite slag melt with a composition of 2FeO·SiO2. The quenched samples were characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy to observe microstructures of the compositions of the matte and slag, unreacted mineral particles, and the presence of magnetite precipitates. The conditions to form magnetite under the hot-thermocouple experiments were qualitatively discussed in terms of the Cu–Fe–S–O–SiO2 phase diagram.


Copper smelting Ignition In situ observation Microstructure 



This research was financially supported by Grants-in-Aid for Scientific Research (B) No. 15H041617 from the Ministry of Education, Science and Culture of the Japanese Government, 2015–2017.


  1. 1.
    Sridha R, Toguri JM, Simeonov S (1997) Copper losses and thermodynamic considerations in copper smelting. Metall Mater Trans B 28B:191–200. CrossRefGoogle Scholar
  2. 2.
    Northey S, Haque N, Mudd G (2013) Using sustainability reporting to assess the environmental footprint of copper mining. J Clean Prod 40:118–128. CrossRefGoogle Scholar
  3. 3.
    Wang Q, Guo X, Tian Q (2017) Copper smelting mechanism in oxygen bottom-blown furnace. Trans Nonferrous Met Soc China 27:946–953. CrossRefGoogle Scholar
  4. 4.
    De Wilde E, Bellemans I, Campforts M, Guo M, Vanmeensel K, Blanpain B, Moelans N, Verbeken K (2017) Study of the effect of spinel composition on metallic copper losses in slags. J Sustain Metall 3:416–427. CrossRefGoogle Scholar
  5. 5.
    Kojo IV, Storch H (2006) Copper production with Outokumpu flash smelting: An update. In: Kongoli F, Reddy RG (eds) Sohn Inter Symp Advanced Processing of Metals and Materials, vol 8—Inter Symp on Sulfide Smelting 2006, TMS, Pittsburgh, pp 225–238Google Scholar
  6. 6.
    Kuman T, Ishida S, Wase K, Asano N (1980) Fundamental studies on the oxidation of copper concentrates in the shaft of flash smelting furnace. J Min Mater Proc Inst Jpn 96:559–564. Google Scholar
  7. 7.
    Jörgensen FRA, Koh PTL (2019) Combustion in flash smelting furnaces. JOM 53:16–20. CrossRefGoogle Scholar
  8. 8.
    Kemori N, Ojima Y, Kondo Y (1990) Optical microscopic examination of suspended copper particles in a flash furnace. J MMIJ 106:545–550. CrossRefGoogle Scholar
  9. 9.
    Yanagase T, Morinaga K, Kang JS, Kammel R (1982) Direct observation of matte-slag melts on hot thermocouple. Metallwissenschaft und Technik 36:540–543Google Scholar
  10. 10.
    Arman Arma LH, Takebe H (2017) Viscosity measurement and prediction of gasified and synthesized coal slag melts. Fuel 200:521–528. CrossRefGoogle Scholar
  11. 11.
  12. 12.
    Sohn HY, Chaubal PC (1993) The ignition and combustion of chalcopyrite concentrate particles under suspension-smelting conditions. Metall Trans B 24B:975–985. CrossRefGoogle Scholar
  13. 13.
  14. 14.
    Yazawa A (1974) Thermodynamic considerations of copper smelting. Can Metall Q 13:443–453. CrossRefGoogle Scholar
  15. 15.
    Kemori N, Denholm WT, Kurokawa H (1989) Reaction mechanism in a copper flash smelting furnace. Metall Trans B 20B:327–335. CrossRefGoogle Scholar
  16. 16.
    Imris I, Sanchez M, Achurra G (2004) Copper losses to slags obtained from the El Teniente process. In: Procs. VII Inter Conf on Molten Slags Fluxes and Salts, The South Africa Institute of Mining and Metallurgy, pp. 177–182.
  17. 17.
    Roghani G, Takeda Y, Itagaki K (2000) Phase equilibrium and minor elements distribution between FeOx–SiO2–MgO–based slag and Cu2S–FeS matte at 1573 K under high partial pressures of SO2. Metall Mater Trans B 31B:705–712. CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  1. 1.Department of Materials Science and Biotechnology, Graduate School of Science and TechnologyEhime UniversityMatsuyamaJapan

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