How to extract antimony

The extraction methods of antimony are mainly divided into two categories: pyrometallurgy and hydrometallurgy, each of which is further subdivided into multiple technologies based on the type of ore and process requirements. The following are the main methods and characteristics of antimony extraction:

1. Pyrometallurgical smelting

Pyrometallurgical smelting is a traditional antimony extraction method suitable for processing sulfide antimony ore and oxide antimony ore, mainly including the following steps:

Volatile roasting/smelting: Oxidation of antimony sulfide ore at high temperatures to produce easily volatile antimony trioxide (Sb2O3), which is then collected through a dust collection system for antimony oxide powder. ‌

Reduction smelting: Mix antimony oxide powder with a reducing agent (such as coal) and reduce it to metallic antimony in a reverberatory furnace. ‌

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Refining: Alkaline refining is carried out by adding soda ash and blowing air to remove impurities and improve the purity of antimony.

The advantages of pyrometallurgy are mature process and strong adaptability, but there are problems such as high energy consumption and environmental pollution (such as SO2 emissions). ‌

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2. Wet smelting

Wet smelting is an environmentally friendly extraction method suitable for processing complex antimony ores and low-grade ores, mainly including the following two processes:

Acidic hydrometallurgy: using ferric chloride or chlorine gas as leaching agents, antimony is leached under acidic conditions, and then metal antimony or antimony white is prepared by electrodeposition or hydrolysis methods. ‌

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Alkaline hydrometallurgy: using a mixed solution of sodium sulfide and sodium hydroxide to leach antimony, and then obtaining high-purity metallic antimony through electrodeposition. This method has the advantages of low energy consumption and minimal pollution.

The advantages of wet smelting are good environmental protection and low energy consumption, but high equipment anti-corrosion requirements and complex processes.

3. Special processes

Precipitation melting: suitable for processing rich ores, producing crude antimony directly through melting method, but not suitable for processing lead containing ores. ‌

Antimony white production: Fine antimony is melted in a reverberatory furnace and blown into air for oxidation to produce antimony trioxide (antimony white), which is widely used in flame retardants and other fields.

4. Complex ore processing

For complex antimony lead ores, a combination of boiling furnace roasting and reflection furnace reduction smelting is commonly used to separate antimony and lead, and recover precious metals.