MINING CHEMICALS
Calculated chemistry
Chemistry innovations in various parts of the mining chain can bring big productivity and environmental wins, reports Paul Moore
BME has developed a unique solution for colloidal silica in copper and cobalt leaching
The world of mining chemicals is characterised by applying innovative approaches to specific mineral processing problems. And this includes leaching and SX-EW. Following decades of challenges in the mining sector caused by colloidal silica in copper and cobalt leaching, BME Metallurgy told IM that it has succeeded in developing and applying an innovative solution that promises potential in other commodity segments.
According to Daniel Verwey, Business Development Manager at BME Metallurgy, colloidal silica can cause serious operational issues in hydrometallurgical plants and particularly in solvent extraction.“ For many years, process plants have grappled with the impacts of silica, a highly prevalent gangue mineral that is leached into solution during acid leaching of valuable metals,” said Verwey.“ Depending on its quantity, it can undermine the efficiency of the extraction process – even to the extent of shutting down the process.”
Partnering with Innospec – who provide a specialised coagulant called DEHSCOFIX ® SC12 – BME Metallurgy assisted its customer MMG to apply this novel solution at its Kinsevere copper mine in the DRC.
“ The product is designed to remove colloidal silica by promoting coagulation of particles,” he explained.“ It binds to the particle surface and destabilises the colloid, so that the coagulated particles can be flocculated and removed from the solution.”
The removal of the colloidal silica in Kinsevere’ s solvent extraction plant delivered many important benefits, including a reduction in total suspended solids, in crud formation and in entrainment. Importantly, there was increased pregnant leach solution throughputs – allowing improved copper production and cathode quality.
The Kinsevere project demanded considerable laboratory test work conducted with DEHSCOFIX ® SC12, he said. This showed not only that it could remove a significant proportion of colloidal silica from the pregnant leach solution, but there was an improvement in phase disengagement time and an elimination of stable emulsion formation. Plant trials were then conducted, where these results were confirmed.
“ In its full plant implementation of this coagulant, MMG Kinsevere used the DEHSCOFIX ® SC12 coagulant to dose the leach discharge slurry,” he said.“ The positive outcome was that the silica in pregnant leach solution was reduced from an average of 1,400 ppm to below 500 ppm.”
This resulted in the solvent extraction plant immediately recovering its stability and resuming operations at full capacity – bringing production back to historical levels and improving the quality of its copper cathodes.
So successful was the result that MMG and BME Metallurgy presented the outcome of the project in a joint paper at the Southern African Institute of Mining and Metallurgy( SAIMM) Copper and Cobalt Africa conference in 2023 in Livingstone, Zambia. Verwey went on to present an update on the DEHSCOFIX ® SC12 solution at the SAIMM Hydrometallurgy for the Future conference in 2024 in Cape Town.
“ Our collaboration with Innospec and our customers has allowed us to replicate these results on a number of other copper mines in Africa,” said Verwey.“ With the growth in demand for uranium, we have also been working on its application in uranium plants; our successful test work confirms that this solution will work for this commodity, where it has a promising future.”
He noted that these successes were part of BME Metallurgy’ s decade-long journey to becoming a specialised provider of chemicals and solutions that delivers process efficiency and improvement.
Draslovka’ s glycine leaching progress
Draslovka is a chemical technologies, products and services company, well known in mining as a leading global producer of sodium cyanide, a chemical vital for gold recovery, however, arguably its most important contribution to the sector is its Glycine Leaching Technology( GLT), a proprietary technology that leaches metals( including gold, copper, nickel and cobalt) in a more profitable and sustainable manner. The company states that GLT is further enhanced through its AI-powered solutions such as its in-line mineral analysers and MetOptima AI Metallurgist, unlocking further recovery and throughput improvements.
The company states that GLT enables profitable tailings re-processing, unlocking additional value from mine waste at a fraction of the cost as well as enhancing environmental compliance, reducing carbon footprint and reducing the risk of tailings incidents.
GLT uses glycine, a non-toxic, recyclable and biodegradable amino acid that is commonly used as a food additive, to recover gold, copper, nickel and cobalt. GLT was inspired by nature when researchers at Curtin University in Perth observed plants absorbing gold and other metals out of the soil through the presence of glycine, which carries those metals through the soil and into the plant.
Fundamentally, GLT helps mines extract metals in a way that is more cost effective, more environmentally friendly, and safer for staff and communities around the mine. Draslovka’ s GLT consists of two technologies – GlyCat TM( GlyCat) for extraction of precious metals and GlyLeach TM( GlyLeach) for base metals. Draslovka argues that GLT has the capacity to revolutionise the mining industry and the potential to save mining companies billions of dollars in the long run. It says it reduces processing costs by up to 50 %, enhances a mine’ s sustainability profile by reducing both cyanide usage( by up to 90 %) and carbon emissions, while also extending mine life by lowering the cut-off grade. GLT unlocks significant new production from deposits that were previously deemed uneconomical to process due to their high reagent consumption. The company states that in certain cases, the process also results in higher recoveries. Another benefit of GLT, is profitable utilisation of tailings – with numerous benefits, both environmental and financial.
Sika’ s admixtures boost backfill
A presentation at Paste 2024 in Melbourne led by Sika’ s Aguilar Sánchez, outlined the crucial role that chemicals are playing
58 International Mining | MAY 2025