Aachen High Shear Reactor technology, predominantly used in the gold extraction process, has grown in popularity, as evidenced by commercial minerals processing and metallurgical testwork company Maelgwyn Mineral Services Africa’s (MMSA’s) moving from a first installation in 2009, to 75 units on the African continent by 2024, 25 of which have been installed in South Africa.

A further 14 units are expected to be installed this year, enthuses technology process manager Wiehan Botes.

The Aachen High Shear Reactor is well-suited for processing any gold ores where oxygen availability and cyanide efficiency are critical factors in gold dissolution.

This includes, but is not limited to gold tailings, oxides, transitional ores and refractory ores that are classified as moderately to mildly refractory in nature.

Recently, the company also successfully applied the technology to acid mine drainage water treatment and is now exploring its potential expansion into the copper industry.

Although the majority of the Aachen technology’s success has been in the treatment of mildly refractory ores, the reactors have been especially well received in the South African gold tailings retreatment market.

The technology is an innovative way of extracting more value from gold tailings – the leftover waste material after primary gold extraction from ore has been performed.

Botes adds, the technology aligns well with the specific requirements of the South African mining sector in several approaches such as improving gold recovery from tailings, reducing cyanide consumption in gold extraction from ore and enhancing operational processing efficiencies.

“The Aachen reactor has gained substantial traction in tailings reprocessing, owing to its ability to enhance oxygen mass transfer while enacting shear on the tailing’s particles.”

Botes says the Aachen High Shear Reactor is a highly efficient mass transfer and shear device, in that its high-shear environment facilitates the polishing of tailings particles, consequently ensuring that their surfaces are clean and optimised for cyanidation.

However, the increased throughput rates associated with tailings reprocessing demand greater oxygen input into the slurry, and in this regard, the Aachen reactor’s highly efficient oxygen mass transfer ability reduces the required oxygen supply, compared to that of conventional oxygenation methods.

Aachen reactor units are suited for greenfield and brownfield installations, and can be installed in two configurations either inside or outside the tank or vessel, with the placement of the units depending on operational considerations and possible space constraints.

MMSA prioritises maintenance and support, achieving over 98% equipment availability through routine servicing under its rental agreements. This commitment distinguishes Maelgwyn from its competitors,” concludes Botes.