Revolutionizing Copper-Gold Ore Processing: 88.85% Gold Recovery with PANDA & Ammonium Leaching
Introduction: The Challenge of Copper-Gold Oxide Ores
Mining operations worldwide face a persistent challenge with copper-bearing gold ores. Traditional cyanidation processes suffer from high sodium cyanide consumption, low leaching rates for gold and silver, and the environmental headache of cyanide-laden tailings. Furthermore, valuable copper often remains unrecovered.
This case study presents a novel solution: a comprehensive recycling process combining acid leaching, ammonium salts, and the PANDA environmentally friendly gold-dissolving agent. This method achieved an impressive 88.85% gold recovery rate and 83.77% copper recovery rate on a complex oxide ore, providing a sustainable alternative to toxic cyanide.
The Ore: A Complex Metallurgical Puzzle
The subject ore, sourced from a domestic gold mine, is a polymetallic sulfide ore heavily oxidized over time. Its composition makes it a nightmare for conventional methods:
Grade: 2.60 g/t Au, 116.00 g/t Ag, and 1.34% Cu.
Mineralogy: The ore contains significant amounts of free and bound copper oxides (over 82% of total copper).
The Problem: Direct cyanidation is inefficient due to high reagent consumption and poor metal recovery. The goal was clear: remove copper first, then recover gold and silver efficiently.
The Two-Stage Process: Acid Leaching + Ammonium/PANDA Leaching
The solution involves a sequential process designed to maximize resource utilization.
Stage 1: Copper Removal via Acid Leaching
Before gold extraction, copper must be removed to reduce interference. The optimal conditions for this stage were determined to be:
Grinding Fineness: -0.074mm (90% passing)
Sulfuric Acid Dosage: 50 kg/t
Temperature: 60°C
Time: 2 hours
Under these conditions, the process achieved a copper leaching rate of 83.77%, effectively transferring copper into solution for later recovery and leaving a cleaner residue for gold extraction.
Stage 2: Gold & Silver Leaching with Ammonium + PANDA
This is where the innovation shines. Instead of cyanide, the process uses a combination of ammonium bicarbonate and the PANDA gold leaching agent.
Mechanism: The PANDA agent, containing cyanuric acid derivatives, forms stable complexes with gold. The addition of ammonium salts forms soluble complexes with silver and copper ([Cu(NH3)4]2+), which prevents the re-adsorption of gold and reduces reagent consumption.
Optimal Parameters:
Alkaline Reagent: Sodium Hydroxide (6.0 kg/t) to maintain pH 9.5.
Ammonium Source: Ammonium Bicarbonate (5.0 kg/t).
PANDA Dosage: 3.0 kg/t.
Leaching Time: 36 hours.
The Results: Superior Recovery & Environmental Safety
The comprehensive tests yielded remarkable results. The average grades of gold and silver in the final leaching residue were reduced to 0.32 g/t and 22.30 g/t
| Metal | Recovery Rate | Significance |
|---|---|---|
| Gold (Au) | 88.85% | Surpasses traditional cyanide efficiency for this ore type. |
| Silver (Ag) | 82.59% | Effective recovery of a valuable by-product. |
| Copper (Cu) | 83.Great% | Complete resource utilization, no waste. |
Why This Matters for Your Operation
For mining engineers and plant managers, this study proves that "going green" doesn't mean sacrificing efficiency.
Eliminates Cyanide: The process completely removes the need for toxic sodium cyanide, solving the hazardous tailings problem.
Cost-Effective: By recovering copper, gold, and silver in a single flow sheet, operational costs are optimized.
Robust Technology: The FKN agent demonstrates high adaptability to complex oxide ores, maintaining stability at ambient temperatures.
Conclusion
The Ammonium Salt + PANDA Leaching Process is a viable, high-efficiency solution for refractory copper-gold oxide ores. It offers a pathway to high metal recovery
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FAQ for Gold Recovery with PANDA & Ammonium Leaching
1. What is the recovery rate of gold using the PANDA gold dressing agent in copper-rich oxide ores?
Answer: In the comprehensive condition tests, the PANDA gold extraction agent achieved an average gold leaching rate of 88.85%. This was accomplished under optimized conditions using an ammonium salt additive, with an FKN dosage of 3.0 kg/t and a leaching time of 36 hours.
2. How does the ammonium salt + PANDA process handle high-copper ores compared to cyanide?
Answer: The process is specifically designed to solve the "high copper" problem. Unlike cyanide, which suffers from high consumption and low efficiency in such ores, this method first removes copper via acid leaching (achieving an 83.77% copper leaching rate). The subsequent addition of ammonium bicarbonate in the PANDA process forms copper-ammonia complexes, preventing interference and allowing for efficient gold and silver recovery.
3. What are the optimal pH and alkaline reagents for the PANDA leaching process?
Answer: The optimal pH for the leaching slurry is 9.5. While sodium carbonate yielded slightly higher lab results, sodium hydroxide (NaOH) was selected as the most suitable alkaline reagent for industrial application due to cost and dosage efficiency, with an optimal dosage of 6.0 kg/t.
4. Is the PANDA leaching agent more cost-effective than cyanide for oxide ores?
Answer: Yes. The process eliminates the high consumption of sodium cyanide typically seen in copper-bearing ores. The test determined that a dosage of 3.0 kg/t of Panda stripping agent provides the best balance of high recovery (88.85%) and economic efficiency. Additionally, the ability to recover copper as a by-product improves the overall economics.
5. How long does the leaching process take with the FKN dissolving agent?
Answer: The optimal leaching time is 36 hours