Co–Mn Mineralisations in the Ni Laterite Deposits of Loma Caribe (Dominican Republic) and Loma de Hierro (Venezuela)

Abstract

Cobalt demand is increasing due to its key role in the transition to clean energies. Although the main Co ores are the sediment-hosted stratiform copper deposits of the Democratic Republic of the Congo, Co is also a by-product of Ni–Co laterite deposits, where Co extraction efficiency depends, among other factors, on the correct identification of Co-bearing minerals. In this paper, we reported a detailed study of the Co mineralisation in the Ni­–Co laterite profiles of Loma Caribe (Dominican Republic) and Loma de Hierro (Venezuela). Cobalt is mainly associated with Mn-oxyhydroxide minerals, with a composition between Ni asbolane and lithiophorite, although a Co association with phyllosilicates has also been recorded in a Loma de Hierro deposit. In Loma Caribe, Co-bearing Mn-oxyhydroxide minerals mainly developed colloform aggregates, and globular to spherulitic grains, while in Loma de Hierro, they displayed banded colloform, fibrous or tabular textures. Most of the compositional analyses of Mn-oxyhydroxides yielded 20 and 40 wt.% Mn, with Ni and Co up to 16 and 10 wt.%, respectively. In both profiles, Mn-bearing minerals were mainly found in the transition from the oxide horizon to the saprolite, as observed in other laterite profiles in the world, where the precipitation of Mn-bearing minerals is enhanced because of the pore solution saturation and pH increase.

Nickel mass balance and isotopic records in a serpentinic weathering profile: Implications on the continental Ni budget

“…The genesis of laterite Ni-deposits in tropical conditions has been extensively investigated in Brazil (Colin et al, 1990;Silva and Oliveira, 1995;Ratié et al, 2018), Colombia (Gleeson, et al, 2004), Indonesia (Fu et al, 2014;Fan and Gerson, 2015), Cuba and the Dominican Republic (Gleeson et al, 2004;Aiglsperger et al, 2016;Domènech et al, 2022), New Caledonia (Dublet et al, 2012;Ulrich et al, 2019), Philippines (Tupaz et al, 2020;, and Myanmar (Sun et al, 2022). During weathering, Ni is relatively soluble and may be strongly adsorbed, incorporated, and coprecipitated into Mn and Fe oxyhydroxides in the upper layer, which are rich in goethite, hematite, and Mn oxides (Elias, 2002;Freyssinet et al, 2005;Golightly, 2010;Dublet et al, 2012;Butt and Cluzel, 2013;Ugwu et al, 2019).…”