Geochemical constraints on the mobilization of Ni and critical metals in laterite deposits, Sulawesi, Indonesia: A mass‐balance approach
Geochemical constraints on the mobilization of Ni and critical metals in laterite deposits, Sulawesi, Indonesia: A mass‐balance approach
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DOI：
10.1111/rge.12266
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发表时间：
2021-05
期刊：
影响因子：
1.4
通讯作者：
A. Ito;T. Otake;A. Maulana;K. Sanematsu;Sufriadin;Tsutomu Sato
中科院分区：
文献类型：
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作者：
A. Ito;T. Otake;A. Maulana;K. Sanematsu;Sufriadin;Tsutomu Sato
印度尼西亚是世界上最大的镍矿石生产国之一，预计也将成为一些关键金属（例如钴、钪、稀土元素和铂族元素）的重要潜在来源。然而，很少有研究考察该国的镍红土矿床。在这项研究中，我们调查了印度尼西亚苏拉威西岛索罗阿科和波马拉矿区四个蛇纹石化程度和风化强度不同的红土剖面中镍的富集和关键金属的潜在积累。我们将地球化学评价与质量平衡方法和矿物学分析相结合，以更好地限制红土化过程中影响镍迁移的地球化学因素。蛇纹石化橄榄岩上强风化发育剖面的腐泥土层中镍含量高于未蛇纹石化方辉橄榄岩上弱风化发育的剖面。腐泥土层位中的镍含量与含镍镁页硅酸盐的镍含量有关，这表明镍再活化是剖面中镍富集的主要控制因素。质量平衡计算表明，剖面中获得的 Fe 和 Ni 的量呈正相关。这种关系表明，镍的重新分布可能是由含镍针铁矿的老化（溶解/重结晶）控制的，涉及有机物引起的配体促进溶解和/或表面附近微生物活动的还原溶解。关键金属在特定层位表现出富集。 Co 和稀土元素的富集受到型材氧化区中 Mn-羟基氧化物形成的强烈影响。相比之下，Sc、Pt 和 Pd 显示出残余富集模式，其品位主要受基岩中初始含量的影响。剖面显示 Sc 和 Fe 之间呈正相关，正如其他镍红土矿床的报道一样。在关键金属中，研究剖面中的 Sc、Pt 和 Pd 含量与全球其他镍红土矿床报告的值相当。
Indonesia is one of the largest Ni ore producers in the world and is also expected to be an important potential source of some critical metals (e.g., Co, Sc, rare‐earth elements, and platinum‐group elements). However, few studies have examined Ni laterite deposits in this country. In this study, we investigate Ni enrichment and the potential accumulation of critical metals in four laterite profiles with varying degrees of serpentinization and weathering intensity in the Soroako and Pomalaa mining areas of Sulawesi, Indonesia. We integrate geochemical evaluation with a mass‐balance approach and mineralogical analysis to better constrain the geochemical factors influencing the mobilization of Ni during lateritization. Nickel contents in the saprolite horizon of the profiles that are strongly weathered and developed over serpentinized peridotite are higher than those that are weakly weathered and developed over unserpentinized harzburgite. The bulk Ni contents of saprolite horizons are related to Ni contents of Ni‐bearing Mg‐phyllosilicates, which suggests that Ni remobilization is the main control on Ni enrichment in the profiles. Mass‐balance calculations reveal that the amounts of gained Fe and Ni in the profiles are positively correlated. This relationship indicates that the redistribution of Ni is likely controlled by the aging of Ni‐bearing goethite (dissolution/recrystallization) involving ligand‐promoted dissolution by organic matter and/or reductive dissolution by microbial activity near the surface. Critical metals show enrichment in specific horizons. Enrichments in Co and rare‐earth elements are strongly influenced by the formation of Mn‐oxyhydroxides in the oxide zone of the profiles. In contrast, Sc, Pt, and Pd show residual enrichment patterns, with grades influenced mainly by their initial contents in bedrock. The profiles show a positive correlation between Sc and Fe, as reported for other Ni laterite deposits. Among the critical metals, Sc, Pt, and Pd contents in the studied profiles are comparable with values reported from other Ni laterite deposits worldwide.