Chromafora’s pilot project for a non-cyanide gold extraction process has recently been formally
reported to and fully approved by Sweden’s innovation agency and Co-Funder Vinnova. The results
demonstrate a groundbreaking method with high yield – so far up to 92% – combined with a
competitive economic outlook.
The Swedish impact company Chromafora has successfully developed a pioneering gold extraction
process. The method is cost-efficient and entirely non-toxic and has the potential to become the first
profitable alternative to conventional and hazardous cyanide leaching.
“Our method eliminates the toxic risks associated with cyanide and makes it possible to refine the ore
and gold concentrates directly at the mine site instead of transporting them elsewhere. This benefits
local communities and reduces transportation needs,” explains Johan Berg, Application Manager at
Chromafora and project lead for the gold leaching initiative.
High gold prices have increased interest in gold recovery from both primary mining operations and
secondary streams such as end-of-life electronics. Many countries have already banned cyanide
leaching, creating a strong demand for a competitive and environmentally friendly alternative.
The objective of the pilot project was to further develop the combination of a thiosulphate-based
lixiviant and Chromafora’s metal separation technology, Selmext, and to demonstrate its economic
and environmental potential. The test was conducted in collaboration with a mining company
between 1 March 2022 and 30 March 2025. Pilot-scale leaching yields ranged from 53-92%,
while laboratory yields were between 80-86%. In addition, recovery of the Selmext and
catalytic reagents showed that up to 96% recycling is possible. This result contributes to
economic competitiveness.
“When we assess a hypothetical full-scale plant with a capacity requirement of processing 15,000
tonnes of gold concentrate per year, the total operating cost of Chromafora’s gold leaching process is
comparable to that of conventional cyanide leaching,” says Johan Berg.
The gold leaching work is now entering a new phase. A demonstration plant is currently being
commissioned, and the door is open to new collaborations, with the goal of becoming the a
commercial alternative to cyanide leaching.
Advantages of Chromafora’s gold leaching method include:
- Non-toxic and based on a limited number of well-known chemicals
- A cost-efficient thiosulphate-based method
- Enables internal, direct recycling of almost all process chemicals
- Suitable for on-site leaching and gold recovery at the mine, benefiting local communities and
reducing transportation
Source: im-mining.com
