Categories
Base Metals Junior Mining Precious Metals

Nickel industry – Part 1 – Processing nickel laterites and sulfides

 Blog home

NICKEL MAGAZINERAW MATERIALS

Nickel industry – Part 1 – Processing nickel laterites and sulfides

MAY 03 – 2024

Let’s dive into this new series of articles on sustainability, treatment processes and innovations in nickel production, starting with nickel ores.

Nickel is primarily used in two areas today: stainless steel and other alloys, and chemical uses including batteries. Stainless steel is the largest part of the nickel market, while batteries are the fastest growing.

To meet the global nickel demand, nickel is produced from two main sources: fresh ores and recycled materials. Recycling (whether stainless steel and nickel alloys or batteries) is an important part of the nickel value chain. The very high recylability of nickel is a critical part of its sustainability profile, but most of the nickel market is focused on the fresh material put into the supply chain, now about 3 million tonnes/year.

Two broad ore types

Nickel occurs in two broad ore types:

  1. laterite (oxide) ores, principally located in tropical and sub-tropical areas, and
  2. sulfide ores, principally located in the temperate to sub-Arctic regions.

Major nickel mining locations are depicted in the map – but some of these locations have many operations, and some only one. More than 50 % of nickel produced today is mined in Indonesia. Ore is often processed near the mine site, but there is substantial regional and global trade in nickel laterite ores, and some trade in nickel sulfide concentrates.

Laterite ores

Laterite ores occur as surface deposits and are traditionally separated into two main types: limonites (lower nickel, high iron) and saprolites (higher nickel, low iron). Limonites typically have cobalt as an additional value component, while saprolite is treated for its nickel value only.

Today, limonite ores are mostly treated by leaching, where the ore is reacted with sulfuric acid and the dissolved nickel and cobalt are recovered as nickel-cobalt intermediate products. These intermediates can be refined to nickel metal or directly into the battery supply chain. This processing based on dissolution in water is called hydrometallurgy.Saprolite ores are treated by smelting, where the ore is dried and melted using energy from coal and electricity – often coal-based – to recover the nickel as an iron-nickel alloy. The iron-nickel alloy is generally used directly to make stainless steel. With growing battery demand, we have seen a resurgence of a past practice to convert the alloy into a higher-grade material (nickel matte) for refining. The  processing based on melting materials at high temperatures is called pyrometallurgy.

Sulfide ores

Sulfide ores can be at (or near) the surface or deep underground, and often have additional value  streams beyond cobalt such as copper, platinum, and palladium. Together, these can be worth more than the nickel.

These ores are treated differently to laterites. They can almost always be upgraded at the mine site to a shippable nickel concentrate. The concentrate can then be treated at centralised facilities. Most of these are nickel smelters, where the concentrate is melted  using the energy from the contained sulfur and electricity to create nickel matte which is subjected to further refining, but there are also direct hydrometallurgical approaches in use.

General industry flowchart for fresh nickel materials

General industry flowchart for fresh nickel materials

This is the first in a new series of articles on the nickel industry, written from an inside perspective to offer a deeper view of what we do, how we do it, and some of the challenges in the production of this important and versatile element. 

Future articles will unpack technologies a little bit further, identifying some of the historical and ongoing improvements, some of the sustainability challenges faced by the industry, and some of the potential alternative routes which might come to fruition alongside the current commercial approaches.

This article was first published in our Nickel Magazine VOL 39-1, in April 2024.