Gold elution is the final stretch, the part of the process where months of hard work in the pit finally translate into pure metal.
But when elution performance dips, even slightly, the losses can be serious. Sometimes it’s easy to see, longer cycle times, lower recovery, or dull electrowinning plates. Other times, the system looks fine on the surface but hides inefficiencies that bleed gold over time.
After two decades in this field, here are the five most common problems that reduce elution efficiency, and how we fix them at Bulawayo Elutions.
1. Poor Water Quality
We’ve seen this time and time again: clients blame the carbon or chemicals, but the problem starts with water quality.
If your water has high hardness, iron, or other dissolved solids, it interferes with the chemistry that releases gold from carbon. Hard water forms scale, iron ties up cyanide, and pH fluctuations throw off the entire process.
How to Fix It:
✅ Test your water at least quarterly.
✅ Install a basic filtration or softening unit.
✅ Adjust chemical balances (especially NaOH and CN⁻) to compensate for local conditions.
For a full breakdown of how water chemistry impacts gold stripping, read: Why Water Quality Affects Gold Elution Efficiency.
2. Inconsistent Temperature Control
Gold elution is temperature-sensitive. When your heaters or heat exchangers fluctuate even a few degrees, stripping efficiency drops. Low temperatures slow desorption; excessive heat risks degrading the carbon and damaging the solution chemistry.
Common causes include fouled heat exchangers, faulty thermostats, and scaling buildup from mineral-rich water.
How to Fix It:
✅ Regularly descale heaters and check temperature sensors.
✅ Keep your operating temperature steady between 110–140°C (depending on ZADRA or AARL).
✅ Monitor temperature at both column inlet and outlet, not just the tank.
Operating temperatures differ slightly depending on your system type. Here’s how ZADRA and AARL compare: ZADRA vs AARL: Which Gold Elution System Performs Better in Zimbabwe.
3. Dirty or Degraded Carbon
Even the best system can’t perform well if the carbon is in bad shape. Over time, carbon becomes fouled with oil, fine solids, and metal contaminants that block adsorption sites. This reduces both loading capacity and stripping performance.
How to Fix It:
✅ Use proper acid washing before elution.
✅ Replace carbon after several cycles or when activity drops.
✅ Avoid using carbon that’s been contaminated with organic lubricants or flotation reagents.
If you’re unsure how carbon fits into the elution cycle, this post explains it step-by-step: How the Elution Process Works: From Loaded Carbon to Pure Gold.
4. Incorrect Solution Chemistry
Elution chemistry relies on the right balance between caustic soda (NaOH) and cyanide (NaCN). If concentrations are too low, gold stays bound to the carbon. Too high, and you waste chemicals while risking safety and equipment corrosion.
We often see problems where operators mix solutions by eye rather than measuring precisely, or where buildup in tanks alters the ratios over time.
How to Fix It:
✅ Check caustic and cyanide concentrations before every run.
✅ Calibrate dosing pumps regularly.
✅ Keep tanks clean and free of scale or residues that affect mixing.
5. Poorly Maintained Elution Columns
Blocked nozzles, corroded pipes, or leaky valves can create uneven flow, leaving parts of the carbon bed under-stripped. This is especially common in older systems that haven’t been refurbished or inspected in years.
How to Fix It:
✅ Backwash and clean columns regularly.
✅ Replace valves, gaskets, and piping before leaks become critical.
✅ Schedule full plant inspections every 6–12 months.
If you’re new to gold elution or just want a refresher on why this stage is so important, start here: What Is Gold Elution and Why It’s the Heart of Gold Recovery.
Bonus: Operator Training
Even a perfectly tuned system will struggle if the operators aren’t trained. Small mistakes — like opening valves in the wrong order or skipping pH checks — can undo the chemistry in minutes.
That’s why at Bulawayo Elutions, we don’t just set up your plant. We train your operators to understand why each step matters. That’s the difference between consistent recovery and constant troubleshooting.
Conclusion
Gold elution performance isn’t luck, it’s discipline.
Regular maintenance, clean water, stable chemistry, and proper training are the cornerstones of every efficient plant.
At Bulawayo Elutions, we combine technical expertise with hands-on experience from real Zimbabwean operations. Whether you’re running ZADRA, AARL, or a custom hybrid system, we can help you recover more gold, faster, and more reliably.
