Ore-dressing methods for copper minerals depend on the type and composition of the copper ore as well as the mineralogical associations. Copper minerals can occur as sulfides, oxides, or carbonates, and each type requires different beneficiation approaches. Here’s a summary of the techniques suited to the various types of copper ores:
1. For Copper Sulfide Ores (e.g., Chalcopyrite, Bornite, Chalcocite):
方法: Flotation
Flotation is the most commonly used technique for copper sulfide ores due to their high hydrophobicity.
Collectors like xanthates and frothers are used to selectively separate copper sulfide minerals from gangue minerals.
Additional Techniques:
Grinding and Concentration: Fine grinding liberates copper sulfides from the host rock.
製錬: Once copper concentrates are prepared through flotation, they are sent for smelting to extract metallic copper.
抑制剤: Lime or sodium cyanide may be added to depress unwanted pyrite or other sulfides.
2. For Copper Oxide Ores (e.g., Malachite, Azurite, Cuprite):
方法: Hydrometallurgical (Leaching-SX-EW) or Flotation
Solvent Extraction/Electrowinning (SX-EW): The solution from leaching is processed to extract pure copper metal.
浮選: Sulfidation may be employed to treat oxide ores. This involves adding sulfurizing agents (e.g., sodium hydrosulfide) to convert oxide surfaces into sulfide-like surfaces for flotation.
Direct Smelting: Sometimes used if the oxidation ores yield high copper content after concentration.
3. For Mixed Oxide-Sulfide Ores:
方法: Sequential Flotation or Combination of Flotation and Leaching
Sulfide and oxide minerals are processed separately:
Flotation first recovers sulfides, using selective reagents to suppress the oxidation phases.
The oxide portion is processed by leaching techniques if re-processing is practical.
Alternatively, bulk flotation can recover a mix of minerals, which are then separated during subsequent processing.
4. For Complex or Low-Grade Ores:
方法: Bioleaching or Pressure Oxidation
生物浸出: Certain bacteria (e.g., 鉄酸化硫黄菌) are used to oxidize sulfides, allowing recovery of copper from refractory or low-grade deposits.
圧力酸化: High-temperature processing under pressure decomposes sulfide minerals for copper recovery.
5. For Copper Carbonate Ores:
方法: Leaching
Similar to copper oxides, carbonate ores like malachite and azurite can be treated through acidic heap leaching processes followed by SX-EW.
By carefully analyzing the mineralogical composition of the ores, an optimal process can be chosen to ensure high recovery rates and economic feasibility.
