Key factors affecting nickel recovery during the segregation of laterite ores

ABSTRACT

The segregation process as applied to nickel laterite ores involves the formation of gaseous nickel and iron chlorides which are subsequently reduced to form ferronickel on the surface of a solid carbon reductant. A fundamental study of the process has been carried out using limonite, nontronite and garnierite ores. The study highlighted the significant impacts that ore mineralogy and carbon addition have on the amount of nickel which is segregated rather than retained within the ore due to in situ reduction. These important aspects affecting nickel recovery and the success of the process are discussed in this paper.

RÉSUMÉ

Le procédé de ségrégation appliqué aux minerais de latérite de nickel implique la formation de nickel gazeux et de chlorures de fer qui sont réduits subséquemment pour former du ferronickel à la surface d’un carbone solide réducteur. On a effectué une étude fondamentale du procédé en utilisant des minerais de limonite, de nontronite et de garniérite. L’étude a mis en évidence l’importance des impacts de la minéralogie du minerai et de l’addition de carbone sur la quantité de nickel qui est séparé plutôt que retenu dans le minerai dû à la réduction sur place. Dans cet article, on discute des aspects importants affectant la récupération du nickel et le succès du procédé.

KEYWORDS:

• Carbon reductant
• chloride addition
• in situ reduction
• laterite
• mineralogy
• nickel segregation

Acknowledgements

The authors would like to express their appreciation to Heron Resources for providing the laterite ores used in this study.

Disclosure statement

No potential conflict of interest was reported by the author.

Notes on contributors

David E. Grimsey recently completed PhD studies into the segregation process applied to nickel laterites at the Western Australian School of Mines in Kalgoorlie. David now works as the senior hot metals process engineer at the Kalgoorlie Nickel Smelter.

Eric J. Grimsey is a pyrometallurgist with expertise in process thermodynamics, heat and mass balances and process modelling. He is an Emeritus Professor with Curtin University and an Honorary Fellow of Australasian Institute of Mining and Metallurgy.

Don C. Ibana is an associate professor in Metallurgical Engineering and Extractive Metallurgy at the Western Australian School of Mines, Curtin University. The processing of nickel laterite ores is one of the areas of his research work.

ORCID

David E. Grimsey http://orcid.org/0000-0002-2498-6797

Notes

1. For garnierite, the rate was also controlled by the rate of H₂ generation at the carbon surface by the water gas reaction.

Additional information

Funding

The authors thank the Mineral Research Institute of Western Australian and the Australian Government (Australian Postgraduate Award) for the provision of PhD scholarships for DEG.