In the third of our four-part series on innovation, Steel Thoughts hears from Pedro Prendes, Head of Process Development, Global R&D, about the work being undertaken to develop breakthrough process innovations that deliver sustainability benefits and meet current and emerging environmental challenges.

By Pedro Prendes, Head of Process Development, Global R&D

Although steel has been the backbone of economic development for centuries, with the birth of modern steelmaking linked to the invention of the Bessemer process in the 1850s, it is an industry that has constantly re-invented itself, in terms of the products we make and how we make them. Making steel is an incredibly complex technical process and one that has and continues to evolve as we strive to improve our processes and deliver products to meet today’s societal needs. It is natural therefore that process development sits at the heart of our R&D efforts given the many processes steelmaking involves – from the extraction of iron ore to its processing, reduction into steel, casting and finishing – with every step of the chain offering potential for improvement in terms of cost and efficiency, and crucially the opportunity to minimise the impact of our operations on air, land and water.

That, in a nutshell, is the mission – to support the long-term sustainability of our business in a manner that impacts the triple bottom line, meaning we have a positive impact on people, planet and profit.

Decarbonisation is a great example of where our work supports that mission. The introduction of a carbon tax in Europe, for example, provides us with economic motivation, while as society – for people and planet – we know we need to reduce reliance on fossil fuels.

We’re supporting every aspect of ArcelorMittal’s decarbonisation work, where we’re making a huge effort to reduce CO₂ emissions from our blast furnaces, either by introducing alternatives to mineral coal or by deploying carbon-capture technology. We’re also looking closely at alternative, breakthrough technologies that hold the potential to fundamentally change how steel is made and replace blast furnaces with something else. And this is a good example of how we focus our efforts on advancing the technology readiness of earlier stage, breakthrough technologies, such as our low temperature, iron electrolysis project, Volteron™.   

As a technology, electrolysis has been around since Michael Faraday in the early 19^th century. It is how copper is produced today, by passing an electric current through a solution containing copper compounds to extract copper from impure metal. We’ve been exploring it for ironmaking - using electricity to break down iron ore to produce iron – since 2004, trying to overcome the challenge of taking it from the science lab to industrial scale while also keeping it economical. 

We began with small-scale tests and have gradually scaled up. But it’s not as simple as just adding iron ore to water and flicking a switch. The challenge is doing it at scale - while electrolysis can produce iron directly, it also produces hydrogen, which lowers the efficiency. That’s why we’ve been experimenting with different options for the electrolyte we use. The most promising solution is iron ore mixed with water and sodium hydroxide, heated up to 110 degrees, so low-temperature electrolysis. It looks like molten chocolate – but is very caustic. Trust me, you wouldn’t want to drink it.

This year we will have a plant that will start producing 1-square metre plates of pure iron, 5 mm thick. It’s still R&D but looks like a small factory – a big warehouse with forklifts, cranes and all employees kitted out in appropriate personal protection equipment. The tech holds enormous potential for carbon free ironmaking, and we’ve come a long way, having taken the project from a technology readiness level of 1 to 6, although we do still have a lot of work ahead to reach 9 – active commissioning.

Supporting the circular economy

Steel is inherently circular. All steel becomes scrap and can be recycled. But building an efficient circular economy is a huge challenge. The main problem is that scrap is, by definition, contaminated, making it difficult to use as a feedstock for high-grade finished steel.

That’s why we are developing artificial-vision systems, based on lasers and hyperspectral cameras that can analyse scrap and classify it according to its different impurities, be they copper, silica, zinc, chrome or any other elements that might be present.

In the first instance, we need to confirm that the scrap is what our suppliers say it is, to ensure there is nothing that can damage our steelmaking assets. And then we need to ensure the scrap is used in the optimum mix to deliver the optimum products. As you can imagine, this is an incredibly complex process perfect for artificial intelligence solutions. But ultimately, if you’re producing rails for high-speed trains or automotive steel solutions, there can be no margin for error.

Scrap is only one part of our circular economy challenge though. Steel production creates waste, and we need to turn that waste into something valuable – a co-product - otherwise it will end up in landfill. Take ironmaking for example, when you separate iron from iron ore you create oxygen obviously, but also other materials, silica, alumina. We call this slag, and it has a value – we can use it as an input material to make cement…and that lowers the carbon footprint of cement production, so a win-win, they decarbonise, and we valorise our waste. But we know steelmaking will gradually transition to Electric Arc Furnace (EAF) production, and EAF slag has different properties, it’s not so easy to use it to make cement. This is something we’re looking at closely. We’re working with start-ups and we have our own ideas and are testing them in our labs. In the same way we have turned blast furnace waste into a valuable product, we now need to do this for EAF waste.

A trusted user of air, land and water

People are rightly concerned about the long-term impact of climate change, but air pollution is hitting human health and well-being already. One of the first areas we focused on was the dust from chimneys in our sintering plants, a part of the iron ore treatment process. Sintering accounts for as much as a third of the emissions from a steel plant, so it’s a logical starting point. Our bottom line was: ‘No smoke’. In other words, if you can see it, that’s wrong. Conventional filtering was always done either with electrostatics or bags – similar to a vacuum cleaner. But we developed a hybrid technique that combines electrostatic and bag filters, making them much more efficient and more cost-effective. The technology originally came from the cement industry and people thought it would never work for sinter, until our breakthrough.

However, there’s two types of dust – that you can see and that you can’t - so-called diffuse emissions. These are more difficult to manage and capture - for example, the dust from trucks driving across gravel or conveyors transporting iron ore. Much of this dust is not immediately visible to the naked eye.

That’s why we’ve had to adopt a different approach – deploying advanced sensors like lasers and high-resolution cameras, backed by AI-driven diagnostics, to identify dust ‘hot-spots’ at our plants. That’s vital to managing all our emissions more effectively, and ensuring we comply with evolving environmental standards.

Today, this technology is still at the R&D stage. The main challenge is developing better understanding of the data. For instance, the lasers we use are commercially available but incredibly powerful – they can detect a speck of dust up to 6km away. The problem is that they generate so much information that it’s hard to understand what’s going on. That’s where our expertise comes in.

Protecting precious natural resources

Steelmaking uses a lot of water - for cooling hot metal during the process and for removing scale from the steel surface. It’s no secret the world is facing a water problem, so we need to use this precious resource responsibly. An ideal steel plant should not need any external water. Instead, it should recycle it, clean it and reuse it – and that’s exactly what we are trying to do.

We’ve developed models for some plants where we look at water usage and develop methods for water reuse, even going as far as reusing municipality water from sewage to minimise our water use. And at ArcelorMittal Tubarão, our flagship flat products steel plant in Brazil, R&D played a pivotal role in ensuring optimal design of its desalination plant, which collects and filters sea water, desalinises it via reverse osmosis and then stores and distributes that water, with brine (liquid with a higher concentration of salts after separation) returned to the sea.

A vision for the future

I like to think of the future steel plant as being in a giant dome. Raw materials come in and products – of all kinds – go out. No waste, no dust, and no need for externally sourced water. Everything is re-used, circularity is maximised and there is zero impact on air, land and water. A living and breathing example of the triple bottom line, delivering financial value for our investors and social value for people and planet. There is no reason why technology and innovation cannot deliver that.