A gold recovery process designed by extraction company Sixth Wave is non-toxic, according to the most recent test undertaken by the Vancouver-based company.
The latest test found that effluent resulting from the IXOS process is nontoxic for fish and daphnia, as defined by Canadian environmental standards.
This finding was confirmed by independent H2Labs.
The test is Phase 2 of the Green Lixiviant for Gold Mining research program, which aims to replace chemical reagents for recovery of gold, lithium, rare earth elements, and other metals with green lixiviants. These substances are mostly non-toxic and biodegradable, and emit little or no vapour.
Following treatment with lixiviants, the metal is in concentrated form. Sixth Wave is also researching how to use this process on hard-to-leach and refractory gold.
Results of the phase 1 and 2 of the testing found the technology averaged 95% of the recoverable gold, with 90% less cyanide usage than when using conventional cyanidation.
The company has undertaken testing in lab and field trials in North and South America, and is now testing its IXOS pilot plant with Canadian gold producer Kinross.
Trials of the IXOS technology began in May 2021, including a combination of leaching and recovery tests.
Sixth launched its Green Alternatives for Gold Leach and Recovery initiative, to further develop its IXOS technology, in July 2020. Partners in that research project include Quebec's Centre Technologique des Residus Industriels and Australia's Mining and Process Solutions.
In January, gold miner Rio2 began a second phase of testing of the purification polymer at its Fenix gold project in Chile. Sixth Wave undertook the first round of tests in Salt Lake City facility in August 2021.
