Analysis: Hydrogen peroxide, a multi-use agent crucial to mining – ESI Africa
In this exclusive ESI Africa article with Future Market Insights, we consider the use of hydrogen peroxide as a multi-use agent in the mining industry.
Diamonds, cobalt, oil, natural gas, copper, gold, and diamonds are just a few of the natural resources found on the African continent, making it a significant part of the global mining industry. However, when there are too many mines, there are increased environmental hazards associated with mining. Due to this, the mining industry is using several alternatives to reduce the environmental impact and to increase the yield of the ore.
The use of hydrogen peroxide in mining processes is one such solution. Hydrogen peroxide has three main applications- as a disinfectant chemical, an oxidizer, and a bleaching agent, according to a recent report by Future Market Insights.
This blog will explore the various advantages that hydrogen peroxide has for various mining activities. Different experiments have been conducted in Africa for many years to find an appropriate chemical to reduce mining waste. As a result of these experiments, hydrogen peroxide has proven to be the best chemical for better oxidizing, metal leaching, and extraction, as well as reducing re-entry times in mines.
Mining effluents containing cyanide are increasingly using hydrogen peroxide as a treatment reagent, having the advantage of being a ‘clean’ chemical in the treatment of wastewater. Despite its high concentration and storage for long periods without appreciable loss of activity, hydrogen peroxide is a safe choice for remote locations and in emergency detoxification units where low capital costs and quick start-up are necessities. Diverse local government initiatives in various parts of Africa have further appreciated the effectiveness of hydrogen peroxide.
The Polokwane Declaration, for instance, sets strict targets for mines and the disposal of mine waste. In South Africa, one of these goals is to steer 70% of mining waste away from landfills by 2022, which has recently been revised to ensure that zero waste will go to landfills. There are already several mining conglomerates that have signed the Polokwane Declaration and are adhering to the regulatory framework. The declaration stresses the use of hydrogen peroxide in the treatment of wastewater to reduce the overall emissions of waste.
Have you read?
Introducing ‘climate-smart’ mining on the road to Industry 4.0
The National Environmental Management Act (NEMA) 107 of 1998 and the Waste Act 59 of 2008 are also important pieces of legislation adhered to by local mining operations. These frameworks ensure that mines remain committed to eliminating waste and reusing waste whenever possible. A sustainable mining process is crucial to ensuring the mining sector’s resource efficiency in the long run. Among the mining industry’s priorities should be recovering waste for recycling or using it for energy production.
An experiment was conducted at a South African gold mine to establish that hydrogen peroxide can be used as an effective gold leaching agent. Using pure oxygen, hydrogen peroxide, and violent aeration with compressed air, the oxygen profiles in the pulp were compared. This was done to compare the efficiency of hydrogen peroxide with common oxidants encountered during cyanidation.
As a result of this experiment, it was determined that oxygen necessary for cyanidation can be introduced into a liquid through peroxide-assisted leaching. In this case, the following characteristics were observed: There was a significant increase in gold extraction. During the current cyanidation process, the final gold extraction was completed in 24 to 48 hours, while the final gold extraction (one tried in this experiment) took place between two to six hours. The hydrogen peroxide used during the PAL process does not attack the cyanide. The additional gold recovered allows the PAL process to be implemented without incurring further investment costs or supplementary reagent costs.
Have you read?
Making hydrogen projects cost-competitive
In the future, the plants using the conventional cyanidation technique will likely be much smaller than those using the conventional cyanidation technique. The investment costs will decrease as a result. Using hydrogen peroxide for the extraction and leaching of gold from the gold mines of Africa was a successful attempt. This is because the extraction rate in such a case was much higher than using the process of aeration or any other oxidizing agents. The substance also got much less corroded during the process, which resulted in better gold yields. The popularity of hydrogen peroxide in the mine extraction process has bolstered the growth of the industrial hydrogen peroxide market in Africa.
An improvement in development practices is consistently desired by the mining industry, enabling faster, safer access to underground deposits, and thereby enabling production ramp-up earlier than currently possible. Hydrogen peroxide (HP)-based explosives proved to be a suitable option for Southern African mines. As early cartridge products produced large amounts of gasses, they proved unsafe and ineffective. Due to the use of nitrates in the formulation, toxic fumes such as nitrous oxides (NOx) and carbon monoxide (CO) remain present. As a result of blasting activities, NOx and CO gas levels have a marked impact on the time required to re-enter underground mines.
Re-entry time, thus, refers to the non-producing phase of the process during which the toxic blast gasses get cleared from the underground environment. The production of toxic gasses can be minimized by using an explosive that has a nitrate-free oxidiser and/or a carbon-free sensitiser. It will reduce the time it takes for these gasses to clear so that personnel can safely enter the mine. Reducing non-production time directly increases the amount of time available to perform active work per shift, thus contributing to rapid development.
From our archives:
Op-ed: Hybrid solutions powering new mining frontiers
The HP explosives were tested in mines in Southern Africa, for instance. By using an alternative explosive based on hydrogen peroxide (HP), re-entry times are reduced by an average of 13% both for single-heading operations and multiple-heading operations. Through the use of HP alternative cartridge explosive products, carbon monoxide concentrations are generally reduced by 50% when compared to Ammonium Nitrate (AN) based underground emulsion explosives. The quantities of nitrous oxide are also reduced substantially.
A second optimization that took into account the possibility of reducing the number of blast holes in the face due to the higher energy per weight of the HP product compared to the AN emulsion showed further improvement in reentry time. As per the study, the re-entry times went down by 27% and 32% in single heading operations and multi-heading operations respectively, along with a 62% decrease in carbon monoxide.
Hydrogen peroxide, given its multi-use agent properties, is considered a crucial raw material for the African mining industry. With sustainability at its cornerstone, mining stakeholders are more than willing to investigate raw materials which are comparatively less polluting to the environment. Hence, hydrogen peroxide is emerging as the clear winner. Prominent manufacturers are looking to capitalise on this opportunity and introduce different hydrogen peroxide grades in the African market.
Have you read?
How mining plans to drive down carbon emissions
For instance, Nouryon, an African chemical leader, launched Eka HP, a hydrogen peroxide chemically processed for use in the mining industry. Eka HP is useful in several stages of mining processes, including separation and refining (purification) as well as leaching operations.
While the focus on using non-polluting materials will remain, countries are intending to adopt other alternatives, including digitization and automation. This could possibly lead to limitations of using hydrogen peroxide for mining operations. In spite of this, the continent is expected to retain its position as one of the most opportunistic hubs for hydrogen peroxide production. For instance, South Africa is a major exporter of hydrogen peroxide, with 21% of it being exported to Zimbabwe, being used as a medicament and as a mining raw material. ESI
Find out more about the Future Market Insights report on the Hydrogen Peroxide Market
About the author:
Nikhil Kaitwade is Associate Vice President (AVP) – Market Research at Future Market Insights, ESOMAR-certified market research and consulting firm Future Market Insights (FMI). The award-winning firm is headquartered in Dubai, with offices in the US, UK, and India.
Enlit Africa (the unifying brand for African Utility Week and POWERGEN Africa) invites you to join the conversation 7-9 June 2022 in Cape Town, South Africa.
© All content copyright 1997 – 2021 Vuka Group, unless specified otherwise.