South African chemicals company Axis House has developed and released a new polymetallic range of collectors – PolyQ – to be used in the flotation process to recover base metals from polymetallic ores.
“The PolyQ range of collectors are not only safer than standard reagents (xanthates) but also more efficient,” says Axis House technical laboratory manager Bernard Oostendorp.
The Axis House collectors display a significantly lower hazardous nature and are also more stable in comparison with xanthates, especially in terms of spontaneous combustion.
“The new base metals sulphide collectors present in liquid form, which means they are easier to handle, and no solution preparation is required,” he adds.
The PolyQ range boasts a minimum storage life of a year.
One of the PolyQ collectors, the PolyQ 167, applied on ore from an Axis House client in Turkey, improved the zinc concentrate grade by 9% and reduced iron contamination in the concentrate by 20%, while maintaining overall zinc recovery at plant targets. The product is currently at plant trials.
Local base metals processing plants, including platinum group metal (PGM) plants with copper and nickel by-products, have a renewed focus on introducing replacement collectors for xanthates or on introducing collectors that act as co-collectors to xanthates, he adds.
“Using co-collectors usually reduces the xanthate consumption while targeting specific minerals that are not recoverable by xanthates.”
These technologies are already available to local operations and Oostendorp notes that the collectors are being evaluated at additional operations in South African lead-zinc and PGM mines.
The research and further development of the PolyQ range is being conducted at the Axis House metallurgical laboratory, in Cape Town.
“The laboratory is equipped with the necessary equipment to carry out all flotation-related testwork, which is used during the development stage of reagents,” says Oostendorp.
The PolyQ range was developed over the past 18 months, which required visiting various local processing plants to carry out testwork on ore currently being treated; however, comprehensive testing for the PolyQ collectors has been conducted in Turkey.
Oostendorp explains that its Turkish and South Africa clients present similar mineralogy in terms of valuable metals, and as such, the testing in Turkey has proven to be effective as a base of comparison for similar testing operations in South Africa, especially lead and zinc.
“Apart from the targeted valuable minerals being similar, for example, sphalerite, the sulphide gangue mineralogy, that also plays a large part in reagent selection, is similar as well,” he emphasises.
Oostendorp points out that process-related challenges differ from client to client, and, in the case of Axis House’s South African zinc clients, selective collector development was its highest priority, which Axis House has addressed on site.
He concludes that other PolyQ collector alternatives to xanthates are an exciting development in the market.