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Distribution of bismuth between copper and FeOx-CaO-SiO 2 slags under copper converting conditions

journal contribution
posted on 2024-11-01, 15:22 authored by Lidya Paulina, Douglas SwinbourneDouglas Swinbourne, TakSeng Kho
Ferrous calcium silicate (FCS) slags (FeOx-CaO-SiO2) have been proposed for use in continuous copper converting, because they attack refractories to a much lesser extent than calcium ferrite slag. However, their ability to absorb unwanted minor elements, such as bismuth, from the molten copper is less well known. Bismuth in copper anodes causes problems in the electrorefinery, while in finished copper products it adversely affects their mechanical properties. In this work, the distribution ratio of bismuth between copper and copper saturated FCS slags at 1300°C and an oxygen partial pressure of 10-7 MPa (10-6 atm) was determined by three-phase equilibration. Copper entrainment in slag caused difficulties during data analysis. It was found that the slag/metal bismuth distribution ratio decreased as the CaO content of the slag increased but was much less affected by the Fe/SiO2 (w/w) ratio. The inferred distribution ratios were projected onto the FeO-CaO-SiO2 phase diagram, as was the calculated value of the limiting activity coefficient of BiO1·5 in the slags. The strong similarity between the way in which both bismuth and copper distributions are affected by the slag composition, as well as theoretical considerations, show that BiO1·5 behaves in slags as a neutral metal oxide. As a result, bismuth removal from blister copper is maximized with FCS slags of low CaO content, the Fe/SiO2 (w/w) ratio being relatively unimportant.

History

Journal

Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy

Volume

122

Issue

2

Start page

79

End page

86

Total pages

8

Publisher

Maney Publishing

Place published

Leeds, United Kingdom

Language

English

Copyright

© 2013 Institute of Materials, Minerals and Mining and The AusIMM.

Former Identifier

2006045777

Esploro creation date

2020-06-22

Fedora creation date

2015-01-18

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