New technology could cement Indonesia’s dominance of vital nickel
greenhouse gases. With Western electric-car makers such as Tesla keen to tout the green credentials of their products, that is a big concern. The more fundamental problem is that much of Indonesia’s saprolite has already been dug up and exported, mostly to China.
In 2020 Indonesia imposed an export ban on what is left. But most of the country’s remaining nickel is locked up in deposits of limonite, which are not suitable for the RKEF process. For decades, mining firms have experimented with an alternative called high pressure acid leaching (HPAL).
Instead of melting the ore, it is put in a pressure cooker-like machine and mixed with sulphuric acid, which strips the nickel out. The method works with limonite, and can directly produce the high-purity nickel needed in batteries. But it has been hard to master, with pilot plants costing far more than planned and operating well under their supposed capacity.
Recently, though, that seems to have changed. Three HPAL plants have started up in Indonesia since 2021. Another seven (including five in Sulawesi) are under development, according to the Indonesian Nickel Miners Association.
Most are built with Chinese technology. Two of the three operating plants are based on designs from China Enfi Engineering Corporation, a subsidiary of the China Metallurgical Group Corporation that operates an HPAL plant in Papua New Guinea. Besides their ability to process limonite, HPAL plants are greener too—at least in some ways.
Without the need for high temperatures, they use much less energy than RKEF plants, and so produce less carbon. But the process also produces a great deal of toxic slurry. Known as “tailings" in mining jargon, these are difficult and expensive to dispose of safely.
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