How is nickel mined and processed?

Nickel is primarily mined from two types of deposits: sulfide deposits and laterite deposits. The mining and processing methods differ depending on the type of deposit. Here's an overview of the processes involved in mining and processing nickel:

1.Mining:

a. Sulfide Deposits: Sulfide nickel deposits are generally found deeper underground. To extract nickel from these deposits, underground mining methods are used. This involves creating tunnels and shafts to access the ore body.

b. Laterite Deposits: Laterite nickel deposits are located closer to the surface and are mined through open-pit or open-cut mining methods. This involves removing overburden (vegetation, soil, and rock) to expose the ore.

2.Ore Preparation:

After the nickel ore is extracted, it goes through various preparation stages to remove impurities and increase the concentration of nickel:

a. Crushing and Grinding: The mined ore is crushed and ground into fine particles.

b. Froth Flotation: The finely ground ore is mixed with water and chemicals, including collectors and frothers. Air is then bubbled through the mixture, causing the nickel-bearing minerals to attach to air bubbles and rise to the surface as a froth, which is collected.

3.Smelting and Refining:

a. Sulfide Deposits: The concentrate obtained from froth flotation contains nickel sulfide minerals. It is then processed through a smelting process called roasting, which involves heating the concentrate in a controlled environment to remove sulfur and transform the nickel sulfides into a matte.

b. Laterite Deposits: The laterite ore is typically processed using a hydrometallurgical approach. It involves leaching the ore with sulfuric acid or another suitable solvent to dissolve nickel and other metals. The resulting solution undergoes purification and precipitation steps to separate and recover nickel.

4.Nickel Production:

a. Matte Processing: In the case of sulfide deposits, the nickel matte produced through smelting is further processed using various techniques such as converting, refining, and electrowinning to obtain pure nickel metal or nickel-containing alloys.

b. Mixed Hydroxide Precipitate (MHP): In the case of laterite deposits, the purified nickel solution obtained from the leaching process is typically processed into a mixed hydroxide precipitate, which contains nickel, cobalt, and other valuable metals. The MHP can be further processed to obtain various nickel products.

It's worth noting that the specific processes involved in nickel mining and processing may vary depending on the ore grade, location, and economic factors. Additionally, environmental and sustainability considerations play a crucial role in modern mining operations, and efforts are made to minimize the environmental impact of nickel mining and processing.