REPROCESSING AND RETREATMENT
MWS has been operating Aachen reactors for its tailings retreatment efforts since 2018 , with recoveries typically in the order of 50 % from a head grade of 0.3 g / t , according to Maelgywn
Building upon this success , Maelgwyn has supplied multiple cells into the global copper reprocessing industry and now
has Mobile Modular Plant versions of its cells that can be rapidly deployed as a pre-assembled unit requiring minimal infrastructure .
Diamond opportunities
A revolutionary new concept in fines
scrubbing developed by Multotec Wear Linings is proving to be a game changer
for Ekapa at its Combined Treatment Plant ( CTP ) in Kimberley , South Africa , helping
process and recover both virgin underground kimberlite as well as tailings for retreatment .
The solution is effectively a pulping chute that scrubs and washes the recrushed product after it has passed through the high pressure grinding rolls ’ ( HPGR ) inter-particle tertiary crushing circuit .
The important advantage here , according to Multotec Wear Linings Projects Sales Manager , John Britton , is that the solution performs the scrubbing action faster and more efficiently than a traditional rotary scrubber would , and at a much lower cost .
Multotec commissioned two of these pulping chutes at Ekapa Minerals ’ diamond operation in late 2019 where they have been operating consistently and in line with expectations , the company said . With the use of patented wave generators , the pulping chute uses the gravitational energy from the slurry flow to create a constant turbulent mixing action that releases the mud , clay and slime sticking to the kimberlite particles .
Ekapa CEO , Jahn Hohne , said : “ The dual chute pulping plant is ideally suited to deconglomerating the HPGR cake product and is exceeding expectations in efficiency and effectiveness at over 600 t / h , which is a major relief on the existing overloaded pair of CTP scrubbers . The net result is a meaningful increase of up to 20 % throughput capacity of the entire processing plant which substantially improves the economy of scale of CTP , feeding directly to the bottom line .”
Multotec ’ s Britton highlighted the efficiency of the system , which can aggressively scrub the material in just three to four seconds as it passes through the chute . This represents just a fraction of the usual retention time in a rotary scrubber , which is three to four minutes , according to the company .
He also emphasised the drastic reduction in running cost the pulping chute achieves .
“ From our experience of plant layouts and flow diagrams , it is clear that fines scrubbers are significant contributors to a plant ’ s capital , operating and maintenance costs ,” Britton said .
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TECHNICAL LIBRARY
PROCESS OVERVIEW
AACHEN
TM
HIGH SHEAR REACTORS
BACKGROUND
The Aachen reactor is a highly efficient mass transfer device developed alongside Maelgwyn ’ s Imhoflot flotation technology .
The unit can be used for any application where it is required to intimately mix a gas with a liquid but has been found to be particularly suitable for gold leaching applications where it is required to boost the dissolved oxygen levels of slurry either prior to , or during the leach reaction .
USES
Can be used to increase the leach kinetics in gold and silver cyanidation . By thinning the Nernst diffusion layer and removing the passivation deposits .
Aachen applications for gold ores include : Oxides Transitional material Refractory ores Gold tailings retreatment
BENEFITS
Increased gold recoveries / lower residue grades Accelerated leach kinetics Reduced cyanide consumption Improved oxygen utilisation Increased tonnages without compromising recovery
SUITABILITY
Aachen reactors are particularly suitable for the treatment of transitional material consisting of a mixture of oxide and sulphides , or where sulphide grades are too low / variable for flotation .
Aachen reactors may be applied in a variety of ways . Can be used on a variety of ore types to increase gold and silver recoveries : Pre-Ox AAL - Aachen Assisted Leach Leachox™
Currently there are over 60 Aachen reactors installed globally .
AACHEN
HIGH SHEAR REACTORS
+ 44 ( 0 ) 2920 340 800 Ty Maelgwyn , 1A Gower Road , Cathays , Cardiff , CF24 4PA , United Kingdom www . maelgwyn . com tsambrook @ maelgwyn . com
APRIL 2021 | International Mining 53