Antimony smelting process generating solid wastes and dust: characterization and leaching behaviors

Area of Science:

• Environmental Science
• Geochemistry
• Waste Management

Background:

• Antimony smelting generates substantial solid waste in China's "World Capital of Antimony."
• Characterization of waste from this process is crucial for environmental risk assessment.

Purpose of the Study:

• To comprehensively investigate the physical, chemical, and leaching characteristics of solid wastes from antimony smelting.
• To assess the environmental hazard posed by heavy metal and metalloid leaching from these wastes.

Main Methods:

• Analysis of physical and chemical properties of four distinct solid waste types: water-quenched slag, arsenic-alkali residue, desulfurized slag, and blast furnace dust.
• Leaching tests were conducted using the Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP).
• Extraction tests were performed to classify the waste.

Main Results:

• Arsenic-alkali residue showed extremely high concentrations of arsenic (As) and antimony (Sb), up to 8.6 × 10⁴ mg/kg and 3.16 × 10⁵ mg/kg, respectively.
• Leaching of Sb from desulfurized slag and water-quenched slag significantly exceeded regulatory limits.
• Arsenic leaching from arsenic-alkali residue was orders of magnitude higher than the regulatory level, indicating extreme hazard.

Conclusions:

• All investigated solid wastes from antimony smelting are classified as hazardous.
• The high leaching concentrations of Sb and As pose significant environmental risks.
• Urgent waste management strategies are needed for antimony smelting byproducts.