10 May 2025
Indonesia is home to the world’s largest reserves of nickel ore — a mineral that plays a critical role across multiple industries, from stainless steel production to electric vehicle batteries. Yet, nickel does not occur in nature as a solid metal. Instead, it is found in the form of nickel ores, of which there are two main types globally: saprolite and limonite.
Although both ores originate from the same rock weathering process, saprolite and limonite differ significantly in terms of composition, color, depth of deposit, and the technologies required for processing.
Here, we take a closer look at the key differences between the two!
Often referred to as "high-grade nickel ore," saprolite typically contains between 1.5% and 3.0% nickel.
Due to its higher nickel content, the extraction process for saprolite ore is comparatively more efficient, utilizing smelting methods such as Rotary Kiln Electric Furnace (RKEF).
However, saprolite deposits are located in deeper layers of the earth’s crust, which presents greater challenges in mining.
The primary product derived from saprolite ore is ferronickel—an alloy of iron and nickel—which is a key raw material in the production of stainless steel.
Limonite is generally classified as "low-grade nickel ore," with nickel content ranging from 0.8% to 1.5%. However, limonite ore also offers distinct advantages due to its cobalt content, which typically ranges between 0.1% and 0.2%.
Processing limonite requires more advanced technologies, such as High-Pressure Acid Leach (HPAL)—a method that involves leaching the ore with heated sulfuric acid to extract valuable metals.
The result is Mixed Hydroxide Precipitate (MHP), a solid mixture of nickel and cobalt, which can be further refined into nickel sulfate and cobalt sulfate for use in various industries, including battery manufacturing.
Harita Nickel is not only engaged in nickel ore mining but also the integrated processing of ore into value-added products. All operations are conducted on Obi Island, located in South Halmahera Regency.
As of August 2024, Harita Nickel’s latest refinery facility has been fully commissioned and is now operational, following the completion of the company’s RKEF smelting facilities in 2023.
Today, Harita Nickel operates a total of 12 RKEF production lines, with a combined capacity of 120,000 tons of contained nickel in ferronickel, alongside 6 HPAL production lines, with an equivalent capacity of 120,000 tons of contained nickel in MHP.
A clear understanding of the distinctions between saprolite and limonite nickel ores highlights the complexity of modern nickel processing—from the inherent properties of the ores themselves to the advanced technologies utilized.
At Harita Nickel, this process is carried out through an integrated and sustainable approach, delivering high-value nickel products while prioritizing environmental responsibility.
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