Saint Petersburg State Polytechnical University, Saint Petersburg, Russia:

Volkov L. V., Professor

“Gipronikel Institute” LLC, Saint Petersburg, Russia:
Kalashnikova M. I., Head of Hydrometallurgical Laboratory, e-mail: MIKal@nikel.spb.su
Solovev E. M., Senior Researcher of Hydrometallurgical Laboratory

For the purpose of identification of cathode copper grade indices, which make an influence on spiral elongation number (SEN), there was made a comparison of actual grade of copper cathodes, manufactured by two groups of producers. The fi rst group of producers included the LBM-registered operations, which produce copper with 400 mm of SEN. The second group included highest grade copper producers (corresponding to М00к State Standard 859—2001 (according to Russian standards), though not certified at the LBM because of the lower SEN). The following grade indices were compared: presence of 9 elements-impurities; cathodes’ thickness; presence or absence of trade mark. Actual grades of cathodes’ and process parameters were taken from the Reports of the world major producers of copper cathodes, based on the primary feed, published in 2007. Eighteen plants (9 plants per each group, including all former USSR producers), which had not manufactured copper with required spiral elongation number, were selected out of 36 Electrolytic Copper Anode Refi neries. The grade comparison was performed using the Principal Components Analysis (РСА), intended for the multivariate data analysis at the variables, set in the digital form. Negative correlation of SEN and content of Se, Te, Bi, S and Ni impurities in copper was revealed, while correlation of SEN and the cathodes’ thickness was positive. Qualitative assessment was made according to the average impurities’ content, which proved the fact that Se, Te and Bi content in the fi rst group copper is 3–4 times lower, in comparison with the second group copper. According to this, mass of each content of element, equal to 0.1–1.0 g/t, is below the State Standard requirement value, equal to 2 g/t. In the first group of producers, average thickness of cathodes is 1.5 times higher than in the second group. There was defined the fact about indirect support, reasoning the difference in the cathodes’ grade: the second group producers’ copper is characterised by higher content of anode slime microparticulate inclusions.

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