Critical metal extraction from laterite ores using reductive dissolution and Fe(II) catalysed recrystallisation

Critical metal extraction from laterite ores using reductive dissolution and Fe(II) catalysed recrystallisation

 

Maximilian Mann¹, Andrew J Frierdich¹, Zhen Wang¹ and Jessica Hamilton²

¹School of Earth, Atmosphere & Environment, Monash University, 9 Rainforest Walk, Clayton, Victoria, 3168, Australia

²Australian Synchrotron (ANSTO), 800 Blackburn Rd, Clayton, Victoria, 3168, Australia

 

Critical metals such as nickel (Ni) and cobalt (Co), are essential for modern green technologies (e.g., solar panels, windmill turbines and batteries)[1, 2]. The majority of the world’s Ni reserves are associated with iron (oxyhydr)oxides or laterites [3], while Co is mostly a by-product of Ni and Cu mining [4]. To produce Co metal, the three main deposit types are nickel sulphide ores, copper sulphide ores and nickel laterites [4]. This work examines the extraction of Co and Ni from various mining ores using Fe(II)-catalysed recrystallisation. Compared to conventional Ni extraction techniques that often involve high-pressure acid leaching, Fe(II)-catalysed recrystallisation has been shown to enhance the release of Ni from goethite and hematite under ambient and circumneutral pH, thus offering an environmentally benign strategy for Ni extraction. Although high Co release was observed, the Ni release was lower as expected. Interestingly, along with the high Co release, a high Mn release was also observed. As Co is often associated with manganese oxides [4], is seems that the Fe(II) used for the recrystallisation lead to a reductive dissolution of these manganese oxides resulting in Co release. This led to the conclusion that the Fe(II) is consumed during a reductive dissolution of cobalt rich manganese oxides. Hence, further experiments are underway to determine if more Co and Ni release can be archived by the addition of more Fe (II). Exploring these alternative Ni and Co extraction and recovery pathways can help reduce the environmental impact of mining and supply the resources needed for green technologies.

 

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