How can we decarbonise the mining and cement industries?

The green transition is increasing the demand for metals and minerals that are needed to produce wind turbines, solar panels, electric vehicles, battery storage, and other electronic equipment. Metals such as copper, lithium and vanadium, are central to green technologies and energy generation and storage.

In a 2020 report, the International Energy Agency states how clean energy technologies generally require more minerals than fossil fuel-based counterparts, with an electric car using five times as many minerals as a conventional car.

Meanwhile, global economic growth and urbanisation continue to increase the demand for cement. Investments in infrastructure provide people with increased mobility, better economic access, improved quality of life and can lower inequality. However, with cement production contributing approximately 7-8% of CO₂ emissions and the mining industry between 4-7%, the path to a low-carbon, sustainable future and higher living standards does not look very green.

Mining and cement have traditionally been seen by the media and public as carbon intensive industries. But the truth is both play a key role for a green, low-carbon future, as well as being central to the realisation of the Paris Agreement and vital to the effective implementation of green recovery packages post-Covid-19.

A World Bank report in 2020 emphasised how “all stakeholders along the mineral and renewable energy supply chains have a vital role to play in the transition to a cleaner energy system to achieve Sustainable Development Goal 7 (Affordable and Clean Energy for All), while ensuring that it does not come at the cost of the climate, the environment, and people” and “the deployment of renewable energy is essential in helping us meet the Paris Agreement, even if it means that more minerals will be needed to get there”.

The question is what actions need to be taken to transition these industries and accelerate solutions towards decarbonisation. At FLSmidth, we have dedicated the overall business and sustainability strategy, to addressing this question. We call it MissionZero. We need to move both the cement and mining industries towards zero emissions by 2030, which requires some drastic engineering decisions.

Let us take the cement industry first. One of the key solutions here is finding alternative fuels. Producing cement is a very energy-intensive process, demanding substantial energy to reach the heat needed for the processes involved. The combustion of fuels counts for 32% of the CO₂ emissions coming from the process. Traditionally fossil energy sources have been preferred for this process, as these provide a stable clean source of energy. But to reduce CO₂ emissions, energy substitution is required.

One energy source is the so-called Refuse Derived Fuels (RDF), where fossil fuel is substituted with the burning of garbage and used in the calcination process. We are seeing the positive effects from projects around the world; with the Vietnamese Cement company VICEM and Golden Bay Cement in New Zealand. In both cases solving two problems at the same time; you remove coal as the source of energy and you combat the waste issue at the same time.

Another CO₂ emission challenge for the cement industry is the use of clinker as the main ingredient. The calcination of the limestone clinker is actually the main source of CO₂ emission from the industry, representing as much as 57% of the total emission from the process. We want to lower the volume of clinker by accelerating the deployment of clay calcination and promoting the use of clinker/clay/limestone blends to reduce emissions. The first step will be to demonstrate industrial-scale clay calcination for use as a binder, a second step is to decarbonise this process using electrification and renewable energy. Clay is particularly interesting as it is abundant in growth regions, which also face a lack of good quality limestone.

Finally, digitalisation will play a key role in bringing down emissions. We have seen under the Covid-19 pandemic a significant rise in customers interested in applying digital solutions. This, of course, is because travel restrictions are making it hard for technicians to come on-site and carry out repairs and maintenance. Digitalising the cement factory processes allow you to apply energy efficiency solutions, make sure that the cement blends you use are exact by automating the sampling and testing the quality, and ensure the right blend of the CO₂-heavy limestone clinker and other less heavy supplementary materials.

While new solutions to decarbonise the industry are becoming available to reduce CO₂ emissions in cement production, this is not enough. In order to accelerate investment by cement producers, demand for low-carbon cement needs to be stimulated through new requirements in public-procured infrastructure projects, integration of low-carbon production processes in building codes, and stimulation of green investments across the sector.

All together it is not one single solution that brings the cement industry towards zero emissions but rather a combination of many innovations.

Just as in cement there are several new solutions and concepts that aim to lower CO₂ emissions and the climate footprint of the mining industry.

The use of water is a specific focus area in our mining solutions. Approximately 70% of mines are located in water-stressed areas. Water is a scarce resource in some areas and mining can be a very water-demanding process. To address this, we have reduced water usage by 95% through larger filtration equipment and dry stack tailings.

We can also process mineral deposits containing arsenic to recover copper, gold, and silver, while complying with stringent environmental regulations. This means refractory ores can be processed at lower temperatures, saving energy use, while it also reduces risk or arsenic pollution from smelters.

When it comes to CO₂ within mining, we must eliminate all diesel-driven equipment, replacing trucks with belt conveyors, which move mined material much more efficiently.

Over the last decade, miners have started to establish in-pit crushing and conveying (IPCC) systems on a large scale, substituting their truck fleets powered by fossil fuels with continuous material transportation on conveyor belts powered by electrical drives. The positive environmental impact of these systems is enormous, while the use of IPCC systems increases the degree of automation and digitalisation bringing additional efficiencies.

In fact, the digital agenda has been growing in importance for mining in terms of productivity – but the benefits will also be seen in sustainability. For instance, by leveraging digital technology advancements, we will be able to connect, capture and predict production data to optimise processes – decreasing waste of water, reducing emissions and energy consumption.

The cement and mining industries are necessary to advance the energy transition. We simply cannot do away with them. Instead, we must work hard to decarbonise the industries by getting them to implement new technology and new processes that reduce carbon emissions as quickly as possible.