تقنية الاستخلاص بالهيلب — التصميم والتشغيل للاستخلاص بالهيلب للذهب والنحاس

Heap Leaching Fundamentals

Heap leaching is a mineral processing technique where crushed ore is stacked in a heap and irrigated with chemical solutions that dissolve valuable metals. It is particularly suitable for low-grade ores that would be uneconomical to process by conventional milling.

Gold Heap Leaching

Process Overview:

• Crushed ore stacked on lined pad (typically -1.5mm or 10mm)
• Cyanide solution sprayed over heap
• Gold dissolves in cyanide solution (Elsner's equation)
• Solution collected and gold recovered

Key Parameters:

• Crush size: Finer crushing improves recovery but costs more
• Irrigation rate: 5-15 L/m²/hr typical
• Leach time: 30-90 days depending on ore
• Cyanide concentration: 100-500 ppm

Copper Heap Leaching

Oxide Copper Minerals:

• Chrysocolla, malachite, azurite respond well
• Sulfuric acid leaching (pH 1-2)
• Lower cost than cyanide
• Established technology

Sulfide Copper Minerals:

• Requires bacteria-assisted leaching (bioleaching)
• Longer leach times
• Lower recovery rates

Heap Leaching Technology

Heap Construction

Pad Liner System:

• Clay or synthetic liner prevents solution loss
• Leak detection system recommended
• Drainage gravel and piping for solution collection

Heap Geometry:

• Typical lift height: 4-10 meters
• Multiple lifts build the final heap
• Solution distribution through drip or spray emitters

Solution Management

• Pregnant Leach Solution (PLS): Carries dissolved gold/copper
• Barren solution: After metal recovery, recirculated
• Make-up solution: Replenishes losses
• Recovery process: Activated carbon (gold), solvent extraction (copper)

WSHT provides heap leaching equipment including irrigation systems, solution management and process design support.