Evaluation of Sc Concentrations in Ni-Co Laterites Using Al as a Geochemical Proxy

Abstract

Scandium (Sc) is used in several modern industrial applications. Recently, significant Sc concentrations (~100 ppm) were reported in some nickel-cobalt lateritic ores, where Sc may be valuably co-produced. However, Sc is typically not included in routine analyses of Ni-Co ores. This contribution examines the relevance of using routinely analysed elements as geochemical proxies for estimating Sc concentration and distribution. Three Ni-Co lateritic deposits from New Caledonia were investigated. In each deposit, Sc is well correlated with Al2O3. The slopes of deposit-scale Sc-Al2O3 regression lines are remarkably controlled by the composition of enstatite from the parent peridotite. In all deposits, maximum Sc enrichment occurs in the yellow limonite, above the highest Ni and Co enrichment zones. Sc- and Al-bearing crystalline goethite is predominant in the oxide-rich zones, though Sc shows a higher affinity for amorphous iron oxides than Al. We propose that, in already assayed Ni-Co lateritic ores, the concentration and distribution of Sc can be estimated from that of Al. Deposit-scale Sc-Al2O3 correlations may be determined after analysing a limited number of spatially and chemically representative samples. Therefore, mining operators may get a first-order evaluation of the Sc potential resource in Ni-Co lateritic deposits at low additional costs.

Reactive Transport Modeling in Porous Fractured Media: Application to Weathering Processes

“…Such mineralogical distribution leads to fractures characterized by high Ni content ranging from more than 10 wt.% to 30 wt.%, and almost no Mg (<1 wt.%), while the matrix is characterized by Ni content ranging from 1 wt.% to 6 wt.%. These results are consistent with field observations where fractures present high Ni concentrations ranging from 10 wt.% to 40 wt.% (Cathelineau et al, 2016(Cathelineau et al, , 2017, while Ni grades do not exceed 2 to 4 wt.% in porous matrix (Butt & Cluzel, 2013;Cathelineau et al, 2016;Teitler et al, 2019Teitler et al, , 2022.…”

Ni(Co) Laterite Deposits of Southeast Asia: A Review and Perspective

“…In addition to Ni ore and economic contents of Co, the Ni(Co) laterite deposits host critical metals or high-tech elements that are increasingly demanded by many industries. These deposits are becoming worth targets for Sc, REE, and PGE [94,[113][114][115][116][117]. Recent studies have shown that Ni(Co) laterite deposits from the Caribbean, Balkan, and Pacific regions are enriched in critical metals (e.g., REE, PGE, and Sc) that could be economically extractable [94,[116][117][118].…”

“…These deposits are becoming worth targets for Sc, REE, and PGE [94,[113][114][115][116][117]. Recent studies have shown that Ni(Co) laterite deposits from the Caribbean, Balkan, and Pacific regions are enriched in critical metals (e.g., REE, PGE, and Sc) that could be economically extractable [94,[116][117][118]. However, few studies have been conducted on the occurrence and distribution of Sc, REE, and PGE in Ni(Co) laterite deposits of SE Asia (see Section 4).…”

Pseudo-Karst Silicification Related to Late Ni Reworking in New Caledonia

“…When peridotites are submitted to a hot and humid climate, the complete olivine dissolution yields a residual soil, the laterite. The latter is formed essentially of goethite and hematite due to the very low solubility of Fe 3+ iron oxides and hydroxides under oxidising conditions [11][12][13][14]. In the lower part of the lateritic profile, Mg-Ni-silicates form at the boundary with the bedrock in the so-called saprolite horizon [12,14].…”

“…The latter is formed essentially of goethite and hematite due to the very low solubility of Fe 3+ iron oxides and hydroxides under oxidising conditions [11][12][13][14]. In the lower part of the lateritic profile, Mg-Ni-silicates form at the boundary with the bedrock in the so-called saprolite horizon [12,14]. The homogeneous lowering of the weathering front and the generation of a weathering horizon of several tens of meters thick implies a duration of at least 10 Ma [15,16].…”