Thiocyanate Removal
Innovative Technologies for Thiocyanate Removal
Thiocyanate (SCN-) is one of the most challenging nitrogen compounds in mine wastewater because it is highly stable and typically passes through standard cyanide destruction circuits virtually untouched. If left untreated, it builds up in process water or discharges into the environment where it can slowly degrade into toxic ammonia and cause downstream eutrophication. BQE Water offers a proprietary non-biological approach to thiocyanate removal that provides unique advantages over sensitive biological systems:
- Selectively targets and removes thiocyanate from mine effluents to below 5 mg/L.
- Utilizes electro-oxidation to break down thiocyanate and recover at least 75% of the nitrogen as free cyanide (CN-) for recycle.
- Eliminates the massive footprint, temperature sensitivities, and biological sludge associated with biological treatment plants.
- Mitigates the risk of algae blooms and nutrient plumes in the receiving environment.
ION EXCHANGE & ELECTRO-OXIDATION
Our process utilizes selective ion exchange to directly target and concentrate thiocyanate from mining effluents into a small volume of brine. This spent regenerant is then treated in an electrochemical cell where the thiocyanate is oxidized. This innovative electro-oxidation process converts the thiocyanate into free cyanide, which can then be safely recycled back into the gold extraction circuit.
INTEGRATION WITH CYANIDE MANAGEMENT
Because thiocyanate generation is inextricably linked to cyanide use in gold metallurgy, our thiocyanate removal technologies are designed to integrate seamlessly into our broader cyanide management strategies. By placing this technology alongside our SART process and existing cyanide destruction circuits, we ensure the holistic, cost-effective management of all nitrogen species on your site.
CASE STUDIES & RESEARCH
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MANAGEMENT OF NITROGEN COMPOUNDS
Read our comprehensive bench-scale treatability study comparing selective adsorption and electro-oxidation against biological systems for the management of thiocyanate and other nitrogen compounds in mine wastewater.
MASTRA MINE
Our expertise in cyanide and nitrogen species management is proven at operations like Mastra, where our SART plant breaks metal-cyanide complexes to recover 80% of cyanide from barren leach solutions, drastically reducing cyanide consumption.
Frequently Asked Questions About Thiocyanate Removal
Why is thiocyanate difficult to treat in mine wastewater?
Thiocyanate is highly recalcitrant and relatively stable, meaning it passes through conventional cyanide destruction treatments virtually untouched. If discharged, it can slowly degrade into ammonia and sulphate, creating long-term toxicity and eutrophication risks for aquatic environments.
Can you recover free cyanide from thiocyanate?
Yes. By combining ion exchange with electro-oxidation, our non-biological process not only removes thiocyanate from the wastewater but can convert and recover at least 75% of the nitrogen contained within it as free cyanide (CN-) for reuse in the gold leaching circuit.