Process Manufacturing builds and delivers turnkey cyanide destruct systems using the SO2/O2 process. The process can treat slurries and solutions at high cyanide concentrations, resulting in low cyanide weak acid dissociable, CNWAD and residual base metals in the tailings prior to tailings impoundment.
This process meets the target limits set by the Ministry of Environment and/or the ICMI Code compliance which can be as low as 1 mg/L CN total or less than 50 mg/L weak acid dissociable (WAD) cyanide for the discharge of final tails into a tailings storage facility. In Process Manufacturing’s cyanide detox system, pure oxygen or air is piped from the gas handling building to the cyanide destruction tank where the main chemical process occurs.
Also from the gas handling building, dry air is supplied to the SO2 storage tank to keep the tank pressurized for the supply of SO2 to the cyanide destruct tank via an automatic metering system.
- Can achieve low cyanide total in a single stage
- Low metals in solution
- Often lowest reagent cost
- Works well on both slurries and solutions
- Can remove iron cyanide
- Red Lake Cyanide Detox
A sodium metabisulfite reagent system can be provided which acts as a backup system in case of any issues with the SO2 system or SO2 supply. We can also provide copper sulphate and lime systems if required.
Online cyanide WAD analyzers can be provided so that SO2 flow rates are added automatically based on the incoming cyanide levels. The final CNWAD result informs the operators that the system is meeting target values at all times. The fully automated process requires little supervision by the mill operators.
Lime is added to the cyanide destruct tank to control the pH at target levels between a pH of 7 to 9. In the chemical process the metals are precipitated as hydroxides. The strong iron cyanide complexes are then precipitated with the addition of copper to form a cuproferrocyanide precipitate.
All systems and structures are assembled and tested at the Process Manufacturing facility in Surrey, BC and shipped complete to mine sites, saving on installation costs.