Environmentally responsible chemical practices demand an integrated approach from mines, across the mining value chain, with hydrometallurgy included, according to Daniel Verwey, Business Development Manager at Omnia Holdings company BME Metallurgy.
Verwey said mining companies are increasingly searching for practical ways to reduce the risks associated with chemicals in applications, such as leaching, flotation, metal recovery and explosives. These efforts are also being driven by stricter legal regulations, in addition to demands by shareholders for mines to operate in a more environmentally sustainable manner.
“In response, BME Metallurgy works alongside these customers to explore safer, more sustainable approaches that reduce environmental risk and waste – while also boosting mines’ productivity and efficiency,” he said.
Minerals for energy transition
He added that producers of minerals that are critical in promoting decarbonisation and a just energy transition, are particularly under pressure to avoid contributing to the very problems that they are trying to solve.
“In many ways, BME Metallurgy is a front runner in ‘green’ hydrometallurgy, which has taken our business to the next level,” Verwey said. “Building on our strong track record in safe handling and application of chemicals, we combine our agility, expertise and R&D capacity to focus on customers’ needs.”
For instance, BME Metallurgy is helping clients to implement chemical circularity by recovering and recycling chemicals back into the system.
Nanofiltration
“We are deploying nanofiltration technology to help mines successfully recover and recycle reagents such as sulphuric and hydrochloric acid, as well as caustic soda,” he explained.
This approach has halved total reagent demand while also saving on the cost of chemical neutralisation – for safer and more responsible transportation of chemicals and waste disposal.
Verwey said that these interventions show how BME Metallurgy had firmly entrenched sustainability into its business model.
“While we may be selling significantly less reagents to mines, we have made a substantial contribution to our clients’ long-term sustainability,” he explained. “In this way, we enhance our brand by building trust and longstanding relationships, while also fostering closer collaboration for continued innovation.”
Replacement of hazardous products with greener alternatives
An example of one of the company’s chemical circularity projects is the replacement of environmentally hazardous products with environmentally friendly alternatives resulting in cleaner production. Verwey said that BME Metallurgy had also made strides in replacing pyrolusite with hydrogen peroxide as an oxidant in uranium acid leaching circuits.
“Hydrogen peroxide is a potent and effective oxidising agent, so only small volumes –substantially less than the volume needed when using pyrolusite – is required,” he said.
This translated into substantial cost savings in transport for mines. Hydrogen peroxide decomposes into water and oxygen, leaving no environmentally harmful residues.
Meanwhile, through its partnership with Hypex Bio, BME has also introduced hydrogen peroxide-based emulsions as a substitute to nitrate-based emulsions for blasting, reducing nitrogen oxide emissions by 90%. He added that hydrogen peroxide-based emulsions were also more energy efficient to manufacture, reducing the carbon footprint of the mining supply chain. Another notable BME initiative entails recycling waste oil, a significant environmental pollutant, into a sustainable energy fuel source within its explosives.
Acid mist abatement
“We have also tested a safer surfactant for acid mist abatement in base metals electrowinning circuits, with the solution already demonstrating significant commercial potential,” said Verwey.
He highlighted that efficiency improvements across the transport logistics value chain could further reduce the impact of mining chemicals on the environment. In one related instance, BME Metallurgy is working with mines to find optimal ways of managing the environmentally responsible disposal of packaging. This issue remains a large problem, he said, especially for remote mines who must incur high costs in transporting empty containers over long distances to the closest licensed off-site landfills or incinerators.
“A possible solution is to establish infrastructure on mine sites to support the procurement of chemicals in bulk or to recycle the packaging into a saleable product,” he said, adding that this required a major shift in the way mines procure chemicals and operate.
Bulk liquids
Meanwhile, BME Metallurgy is also working towards finding better ways of transporting bulk liquids to remote sites, considering that bulk tankers often have to return empty – an inefficient process that contributes to CO2 emissions.
He said moving forward, circularity would become even more important to the mining industry, driving demand for BME Metallurgy’s tailored “green” chemical solutions.
“Water recycling and reuse is a higher priority than recovering reagents, especially for mines located in water-stressed areas such as South Africa,” he said. “This is compounded by the high capital and operational costs for the advanced treatment of large complex contaminated water.”
Verwey said that nanofiltration technology has also proven to be a very effective way of recovering, purifying and recycling water.
“The process provides high water recovery rates, is more energy efficient than some other treatment methods and does not require chemical reagents,” he said.
He concluded by noting that through continued innovation in the safe and environmentally friendly responsible use and handling of chemicals, BME Metallurgy is helping mines align with global goals for a resilient future. This is in line with Omnia’s purpose of ‘Innovating to enhance life, together creating a greener future’.
