Early removal of minor elements avoids dispersing them through downstream processing of concentrates.
Minimising the effect of minor elements
A new beneficiation flowsheet could help unlock the value in ores containing high levels of minor elements.
11 May 2007 | Updated 14 October 2011
As the number of simple, high-grade ore deposits dwindles, operators are turning to more complex, lower-grade deposits that were previously unattractive or uneconomic because of the presence of minor elements.
Minor elements – a major problem
In addition to often being hazardous or toxic, minor elements are often difficult to separate from the valuable minerals in an ore.
Even at low levels in an ore body, minors quickly become concentrated in smelter feeds where they are deported to mattes, metals, gases, slags, dusts and tailings streams at the smelter.
CSIRO Minerals project leader Mr Warren Bruckard explains, ‘As the tonnages processed increase, so too does the dispersion of these hazardous elements into the biosphere. This situation is unsustainable for industry, consumers and the community.’
A potential solution
Through the Centre for Sustainable Resource Processing, researchers from CSIRO, the Australian Nuclear Science and Technology Organisation (ANSTO) and the Julius Kruttschnitt Mineral Research Centre (JKMRC), are developing a process to address the problem of minors deportment and dispersion.
‘We are bench-scale testing an early removal flowsheet in which minors are separated efficiently from valuable minerals at the flotation stage,’ says Mr Bruckard.
“Implementing the flowsheet will help reduce smelter emissions and wastes,
and provide processors greater access to some previously uneconomic deposits.”
Mr Warren Bruckard, project leader, CSIRO Minerals
The clean concentrates are sent to smelters, while the minors concentrate is selectively roasted to capture the minor elements in a low-volume stream.
This stream is then stabilised and sent back to the mine for safe disposal. Any valuable element in the minors concentrate is recovered as a calcine, which can go straight to the smelter with the clean concentrate.
According to Mr Bruckard, the new flowsheet offers several benefits. ‘It will improve management of minor element dispersion and waste disposal, without compromising recovery of valuables. Implementing the flowsheet will help reduce smelter emissions and wastes, and provide processors greater access to some previously uneconomic deposits.’
Learn more about our work to extract value from waste at New integrated slag treatment process creates value.