How Is Antimony Mined and Processed?

Antimony-processing-plant

Understanding how antimony is mined and processed is crucial for investors, manufacturers, and stakeholders in the global mining industry. This guide provides a detailed overview of antimony’s extraction—from geological occurrence and mining techniques to refining and end-use applications.

Antimony (Sb) is a silvery-gray, brittle metalloid most commonly found in nature as stibnite (Sb₂S₃), a sulfide mineral. While it occurs in more than 100 different minerals, stibnite is the primary source used for commercial production.

1. Geological Occurrence

Antimony is typically found in hydrothermal veins, often associated with minerals like gold, silver, and arsenic. 

2. Types of Antimony Ore

The two main categories of antimony ore are:

• Sulfide ores (mainly stibnite): Easier to process and more common.

• Oxide ores: Typically more complex and require different extraction techniques.

3. Mining Methods

a. Underground Mining

The most common method for antimony extraction is underground mining, especially when the ore body lies deep beneath the surface. Tunneling techniques include room-and-pillar and cut-and-fill mining.

b. Open-Pit Mining

For near-surface deposits, open-pit mining is used. This method is more economical for large-scale operations but can have greater environmental impacts if not managed carefully.

c. Small-Scale and Artisanal Mining

In regions like Myanmar and parts of Africa, artisanal and small-scale mining (ASM) plays a key role in antimony production. However, these operations often face challenges related to safety, environmental management, and regulatory compliance.

Once extracted, antimony ore undergoes several steps to separate the metal and produce usable products.

1. Crushing and Grinding

After mining, the ore is crushed and ground into a fine powder to liberate antimony minerals from surrounding gangue materials. This is a preparatory step before beneficiation.

2. Beneficiation and Concentration

a. Gravity Separation

Stibnite has a relatively high specific gravity, allowing gravity separation techniques—such as jigs, shaking tables, and spiral concentrators—to be effective in concentrating the ore.

b. Flotation

Froth flotation is widely used, especially when gravity methods are insufficient. Reagents are added to make the antimony particles hydrophobic, allowing them to attach to air bubbles and float to the surface for collection.

c. Magnetic or Electrostatic Separation

In some cases, additional separation technologies may be used, particularly when dealing with complex or mixed ores.

Once the concentrate is produced, the next step is refining the antimony to a saleable form. Two main methods are used:

1. Pyrometallurgy (Smelting)

a. Roasting

Concentrated antimony sulfide is first roasted in air to convert it into antimony oxide (Sb₂O₃), releasing sulfur dioxide (SO₂) gas

Roasting temperatures are typically in the range of 500–600°C.

b. Reduction

The antimony oxide is then reduced using carbon (usually coke) to produce metallic antimony

The molten antimony is poured into molds or cast into ingots.

2. Hydrometallurgy (Leaching)

For oxide ores and some low-grade deposits, hydrometallurgical methods like alkaline or acidic leaching are used. These involve dissolving the ore in chemical solutions and recovering the antimony through electrowinning or precipitation.

Although more environmentally friendly, hydrometallurgical techniques are still under development for large-scale commercial application.

With growing demand and concerns about supply concentration—over 70% of global antimony comes from China—there is increased interest in developing antimony projects in North America, Australia, and Europe.

Recycling and reprocessing of mine tailings also offer viable alternatives to traditional mining, especially in countries aiming to secure critical mineral supply chains. Welcome to contact for more.