The Ultimate Guide to Nickel Ore Beneficiation

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Nickel is a crucial metal for manufacturing stainless steel and batteries, but it is contained within different types of rocks that require entirely different extraction methods. One type of rock is processed using physical "washing and sorting" methods, while the other requires chemical or high-temperature "smelting" techniques. This article explains these two core methods in plain language and discusses future trends.

Nickel ore is the primary raw material for extracting metallic nickel. Based on genesis and composition, it is divided into two major categories: sulfide nickel ore and lateritic nickel ore (oxide nickel ore). Their compositions and characteristics differ significantly:

1. Sulfide Nickel Ore

 (1) Main Components:

Primarily consists of nickel sulfides. Common minerals include:

• Pentlandite: Chemical formula typically (Fe,Ni)₉S₈, the main nickel-bearing mineral.

• Pyrrhotite: Contains minor nickel.

• Chalcopyrite: Often associated with copper.

Frequently coexists with copper, cobalt, platinum group elements, etc., forming copper-nickel sulfide deposits.

2. Lateritic Nickel Ore (Oxide Ore)

 (1) Main Components:

• Limonite layer: Nickel coexists with iron oxides (containing 1%-1.5% nickel).

• Saprolite layer: Nickel is hosted within silicate minerals (containing 1.5%-3% nickel, high magnesium content).

1. Sulfide Nickel Ore

• Flotation: The primary method. Selective flotation or bulk flotation processes are commonly used to recover nickel, copper, and other metals.

• Magnetic Separation-Flotation Combination: For ores containing pyrrhotite. Magnetic separation is used first for separation, followed by flotation for enrichment.

2. Lateritic Nickel Ore (Oxide Ore)

 (1) Hydrometallurgy:

• High-Pressure Acid Leaching (HPAL): Suitable for low-grade limonitic ores. Acid leaching extracts nickel and cobalt.

• Atmospheric Acid Leaching: Used for saprolitic ores.

• Roast-Leach: Nickel is converted to a soluble state via reduction roasting, followed by leaching.

 (2) Pyrometallurgy:

• Rotary Kiln-Electric Furnace (RKEF) Smelting: The mainstream process, producing nickel pig iron (NPI).

• Sintering-Blast Furnace Smelting: Similar to ironmaking, produces nickel pig iron.

3. Other Methods

• Gravity Separation: Used for pre-treatment or auxiliary recovery of coarse-grained nickel minerals.

• Bioleaching: A potential technology for low-grade or complex ores.

The core objective is crushing, grinding, and enrichment via flotation.

1. Crushing Equipment

（1）Primary Crushing:

• Jaw Crusher

• Gyratory Crusher

（2）Secondary Crushing:

• Cone Crusher

（3）Tertiary/Fine Crushing:

• Cone Crusher

2. Grinding and Classification Equipment

（1）Mills:

• Semi-Autogenous Grinding (SAG) Mill

• Ball Mill

• Rod Mill

（2）Classification Equipment:

• Hydrocyclone

3. Flotation Equipment

• Mechanical Agitation Flotation Machine

• Inflatable Agitation Flotation Machine

• Flotation Column

4. Thickening and Filtration Equipment

（1）Thickener (Clarifier)

• High-Rate Deep Cone Thickener

• Inclined Plate Thickener

（2）Filter:

• Vacuum Disc Filter

• Chamber Filter Press

5. Auxiliary Systems

• Reagent Feeders

• Slurry Pumps

Nickel ore beneficiation primarily follows two routes: "physical flotation" for sulfide ores and "metallurgical extraction" for lateritic ores. The former produces high-grade concentrate through crushing, grinding, and flotation, offering lower costs and higher efficiency. The latter requires complex processes like high-pressure acid leaching or high-temperature smelting to produce nickel pig iron or intermediate products. Future technology will develop towards intelligence and low-carbon practices. By enhancing slag utilization and recycling, a more efficient and sustainable nickel resource supply chain will be established.