Cyanide-Free Gold Extraction and Arsenic-Capture: Quebec Chemical Company Pioneers Non-Toxic Gold Extraction and Processing

       A chemical company from Quebec has developed a cyanide-free and generally non-toxic method to extract gold from mineral ores. This could relieve companies from environmental compliance burdens associated with toxic gold extraction and processing. Dundee Sustainable Technologies is offering a patented process they call GlassLock, which safely removes and recovers arsenic from gold ore. The process can replace the current practice of utilizing cyanide leaching to remove arsenic. Both arsenic and cyanide are highly toxic. In the process, arsenic is isolated and turned into inert glass. Andy Corbley of Good News Network explains the GlassLock arsenic removal process, followed by an explanation from the company's website: 

“Mixed with common components like silica, recycled glass, and hematite, the arsenic is then vitrified into a stable and insoluble glass product that can be removed and processed far more easily.”

     Below, he explains the CLEVR gold circuit extraction process, followed by an explanation from the company's website:

“Dundee’s gold circuit process uses sodium hypochlorite and sodium hypobromite in ambient pressures and room temperature to extract gold from ore at a fraction of the time of the cyanide-in-leach method. Contact time is short, just 2 hours compared to 36 hours, and the process operates in a fully closed loop. All chemicals are recycled within the circuit for reuse.”

     They call the cyanide-free extraction process CLEVR. 

     Neither of the two processes requires tailing ponds, which also reduces environmental risks of rain, flooding, acid mine drainage, and dam breaches.

     Mining companies are testing and using the process, including Freegold Ventures Limited, which is using the GlassLock process on its Golden Summit project in Alaska.

“In tests, Freegold used GlassLock to recover 95% of the gold contained in the ore while isolating 98% of the contained arsenic as inert glass, reducing the toxicity from 7% to 0.17%. It also was able to remove the need for cyanide leaching, and the resulting gold concentrate would be direct-to-smelter quality.”

“The results of this program were extremely positive and encouraging for Freegold as it advances the project through Pre-Feasibility,” the company wrote in a press release.

     Freegold is testing GlassLock among other oxidation processes, but it looks encouraging. Freegold notes in a press release:

“Recent results from the GlassLock Process™ demonstrate an enhanced gold grade in concentrate, with no measurable gold losses during processing, resulting in the production of a saleable, direct-to-smelter concentrate that avoids the use of cyanide while significantly reducing arsenic content. The concentrate would be highly attractive to numerous end users.(Source: PR, December 16th, 2025). Ongoing trade-off studies will determine whether the additional processing and capital investment required for further treatment are warranted, or whether a simpler gravity- and CIL-based flowsheet is more cost-effective despite lower recovery rates.”

 

 

References:

 

Quebec Firm Pioneers Cyanide-Free Gold Extraction and Arsenic-Capture to Clean up Mining Industry. Andy Corbley. July 10, 2026. Quebec Firm Pioneers Cyanide-Free Gold Extraction and Arsenic-Capture to Clean up Mining Industry

Dundee Sustainable Technologies. Website. Dundee – Sustainable mineral extraction technologies

Freegold Provides an Update on its 2026 Plans. Freegold Ventures Limited. January 23, 2026. Freegold Provides an Update on its 2026 Plans | Freegold Ventures Limited