Australia is one of the world’s leading producers of critical mineral substances, forming the backbone of our economy. Our iron ores contribute approximately $130 billion annually as our largest export and mining endeavour. Mining giants, Rio Tinto and BHP profit incredibly from this being the main exporters of iron ore in the country. Their mining efforts expand to bauxite (aluminium ore), copper, salt, ferrous metallics, lithium, titanium, and metallurgical coal amongst other natural minerals. The level at which these companies mine, however, means they contribute large amounts of carbon dioxide (CO2) into the atmosphere. Polluting the air in this way is detrimental to human and environmental life by accelerating global warming and climate change. Such, Rio Tinto and BHP are required to de-carbonise their operations and scale towards net zero emissions by 2050. Aware they can’t solve the issue on their own, the mining giants have combined efforts and resources in a joint investigation to decarbonise iron ore processing. Alongside BlueScope steel, the group are leveraging their collective knowledge and experience to develop Australia’s first Electric Smelting Furnace (ESF) pilot plant.
Climate Change & the Paris Agreement
An unavoidable threat to our future, climate change poses a significant risk to everyday human life and our evolution. To combat this, or at least to lessen its effects, humanity must take pivotal steps to reduce greenhouse gas (GHG) emissions. Hence, the Paris Agreement, a legally binding international treaty adopted by 196 Parties was established in 2015. This Agreement aims to hold global average temperature increase to well below 2°C above pre-industrial levels. As an ambition, it aims to limit the temperature increase to 1.5°C. Such, industries that play a significant role in GHG emissions like the iron ore industry are required to dramatically reduce their emissions and alter their practices.
“The carbon intensity of iron and steelmaking requires profound change to meet the needs of our planet and our climate objectives. We must find better ways to enable these materials to be made more sustainably through leveraging technology.”
- Rio Tinto Iron Ore Chief Executive, Simon Trott
This, of course, requires incredible financial investment from industry bodies and government with the value of decarbonisation projects staggeringly high. In fact, Rio Tinto has estimated an investment of $7.5 billion is required to make these projects a reality. It is interesting to note the comparison when considering the budget for Brisbane’s 2032 Olympic games, valued at $7 billion. What is more important?
Regardless, industry bodies agree on three common conclusions; the need to transform the way we produce and consume energy and land; huge investments in low-carbon energy are required; and there is a growing demand for essential minerals needed to make the shift to cleaner energy.
Scope of CO2 Emissions
As discussed, GHG emissions are the primary cause of increased global temperatures and climate change. Data gathered from Rio Tinto’s 2022 Climate Scope report reveals alarming data on the levels at which certain mineral mining and processing emits CO2. In total, the steel industry contributes 8% of the world’s total carbon emissions. This staggering number is primarily attributed to the processing of mineral products into sellable products. Of this, the majority of CO2 emissions result from iron ore processing, a contribution of 386.6 million tonnes (mt). Second to this is bauxite and alumina, key ingredients to produce aluminium – contributing 147.3 mt. This is followed by 7.1 mt of CO2 by salt and 5.9 mt by titanium dioxide feedstock. Other mineral processing contributes 1.6 mt with 0.5 mt produced by copper concentrate.
Processing minerals is a hard-to-abate activity in which high temperatures are required, directly producing GHG emissions – 80% of CO2 emissions result from this while the remaining 20% are from mining operations. The most significant emissions occur from purchased and generated electricity, contributing 41%, carbon anodes in aluminium smelting and reductants in titanium dioxide furnaces contribute 21%, while fossil fuels used for heat in processing plants and alumina refineries produce 20%, and diesel consumption in mining equipment and rail fleet creates 13% of emissions.
In Canada and South Africa, the extraction and processing of Titanium dioxide (TiO2) by Rio Tinto significantly contributes to the company’s carbon emissions, accounting for 9% of its total Scope 1 and 2 emissions in 2022. TiO2 absorbs ultraviolet rays and reflects 96% of light, making it an essential ingredient in sunscreen and heat-reflective paint. When used in paint, TiO2 significantly reduces the energy consumption required by air conditioning as heat is reflected off the building. TiO2 is also used in battery and solar technology, making it an all-around essential commodity.
It may be determined that transporting these processed minerals across the country defeats the purpose of decarbonising due to transport emissions. However, according to Rio Tinto CEO Simon Trott, transport emissions are a relatively small contribution. Although, they intend to reduce emissions in this area anyway by assessing new locations for processing to occur. This will consider locality in relation to mining infrastructure and utilities.
Mineral Mining and Processing Methods
Mineral processing can occur in several different ways, for steelmaking there are two primary methods currently practiced. 99% of iron ore is processed via the Integrated Blast Furnace route (BF/BOF). This method combines iron ore and metallurgical coal with other additives to produce steel (See Figure 2). The remaining 1% of iron ore is processed using natural gas in an Electric Arc Furnace (EAF) to produce direct reduced iron (DRI) which is then converted into liquid steel.
Figure 2: Methods for Steelmaking
The production of Titanium dioxide (TiO2) involves the processing of ilmenite ore, a composition of titanium dioxide and iron oxide. This process requires significant amounts of coal and electricity to heat the ore to approximately 1,700 degrees Celsius. During the smelting phase, carbon within the coal reacts with the ore, transferring oxygen from the ore to the carbon, which generates carbon monoxide (CO) and separates the iron units. This reaction, known as reduction, consumes a huge amount of energy, resulting in the generation of smelter gas. 80% of this smelter gas is repurposed as process heat in other plants, while the remaining 20% is released into the atmosphere (See Figure 3).
Figure 3: Titanium Dioxide Production Method
Exploring Decarbonisation Initiatives:
As discussed, decarbonising mining operations is essential to ensuring the future of the industry – and in turn, the environment. Throughout the mining industry, several methods are being trialled to assess the best possible option to reduce CO2 emissions, in this section we primarily explore Rio Tinto’s initiatives.
Iron Ore Specific Methods
Rio Tinto has launched several sustainability initiatives in its iron ore sector, focusing on renewable energy and emission reduction. The company is investing $600 million in developing 200MW solar power facilities and 200MWh of energy storage in the Pilbara region. A 34MW solar facility at Gudai-Darri is already operational.
In collaboration with Scania, Caterpillar, Volvo, and Komatsu, Rio Tinto is working on integrating battery-powered trucks and autonomous haulage solutions to decrease CO2 from its operations. Additionally, they are also conducting a trial with BP to explore the use of marine biofuels, aiming to reduce GHG emissions from shipping activities.
The Bio Iron Process
The innovative Bio Iron process marks a departure from traditional methods, utilising raw biomass and microwave energy instead of coal to convert iron ore into iron. This approach holds the potential for net-negative emissions when combined with renewable energy and carbon capture and storage technologies. The process involves mixing iron ore fines with raw biomass material, typically agricultural waste, and heating the mixture using the gas released by the biomass, alongside microwaves powered by renewable energy. Impressively, Bio Iron consumes less than a third of the electricity required by other emerging technologies. While still emitting CO2 during the process, this is mitigated through the offsetting capacity of fast-growing plants that absorb CO2 through photosynthesis, specifically utilising lignocellulose found within leaves, straw, and stalks of plant products.
Electric Smelting Furnace
Rio Tinto, BHP, and BlueScope Steel’s collaboration is advancing the development of Australia’s first Electric Smelting Furnace (ESF) pilot plant. This initiative involves converting iron ore into direct reduced iron (DRI) before being charged in the ESF, a step that circumvents the use of metallurgical coal. Since metallurgical coal is a significant source of CO2 emissions in traditional steelmaking, its elimination reduces emissions by up to 80%.
The ESF’s ability to accept various raw materials reflects its scalability and adaptability for future use. The ESF also allows for integration with existing downstream infrastructure in steel plants, facilitating a smoother transition to this technology. With the ability to reduce emissions, flexibility, and compatibility with existing systems the ESF is paving the way for a more sustainable steelmaking future.
Aluminium Specific Methods
In QLD, Rio Tinto plans to repower its aluminium smelting assets with up to 4GW of wind and solar energy. This transition is supported by partnerships with energy firms that will provide firming and storage solutions to ensure a stable supply of renewable energy. Additionally, for its QLD alumina operations, Rio Tinto has proposed a pre-feasibility study for a double digestion project, aiming to reduce both emissions and operational expenditure.
The Hydrogen Pilot Plant
Rio Tinto is actively advancing a hydrogen pilot plant in response to the carbon-intensive nature of aluminium production, where the energy-intensive process of creating alumina results in significant GHG emissions. The focus is on the integration of hydrogen in alumina refining, with plans to transition the plant to green hydrogen. This shift holds the potential to curtail emissions by 500,000 tonnes annually, equivalent to removing 109,000 internal combustion engine cars from the road. Notably, the combustion of hydrogen only releases steam, offering an environmentally favourable outcome. The captured steam proves versatile, finding use in other refinery processes before being condensed into water, which is then recycled to generate additional hydrogen. The production process underscores the importance of renewable energy and water sources for achieving genuinely green hydrogen. Crucially, the steam captured from the hydrogen-fired calciner serves as a substitute for fossil fuels in the refinery process, contributing to a 50% reduction in the overall carbon footprint. This initiative boasts good combustion properties, seamlessly integrates into existing infrastructure with ongoing engineering solutions, and has the flexibility to be powered by solar and wind energy sources.
Copper and Minerals Specific Methods
Committing $537 million, Rio Tinto in partnership with the Canadian government, is decarbonising its Iron and Titanium Quebec operations. This investment aims to reduce CO2 emissions by 70%, while also enhancing the value chains of critical minerals and metals, including the production of titanium metal, scandium, and lithium. A key component of this initiative is the BlueSmelting demonstration plant, which employs world-first technology to achieve these goals.
Furthermore, the company has entered into a 20-year power purchase agreement with Voltalia to procure solar power, underscoring its shift towards renewable energy sources. In addition to these efforts, a pilot project at Boron is exploring the use of renewable diesel, with further trials planned at Kennecott.
Further Decarbonisation Methods
The BlueSmelting Process
The BlueSmelting process, integrates mature technology with new technological advancements, incorporating an additional step before the traditional smelting process. This innovative method significantly reduces the need for coal and electricity, leading to a 30% reduction in emissions. Future stages of this process aim to further decrease environmental impact by combining smelter gas with green hydrogen and eventually using green hydrogen as a standalone input.
To ensure the viability and safety of these advancements, comprehensive studies are being conducted to assess both the effectiveness of the process and any associated safety risks. Moreover, Rio Tinto is exploring the use of sustainable biomass as an alternative to coal. If all stages of the BlueSmelting process are implemented successfully, the company anticipates a potential reduction in emissions by up to 95%, marking a significant step towards more sustainable metal production practices.
Figure 4: The BlueSmelting Process
The Yarwun Hydrogen Calcination Pilot Project
Rio Tinto is advancing the Yarwun Hydrogen Calcination Pilot Project, incorporating a 2.5MW on-site electrolyser to provide green hydrogen to the Yarwun refinery. This initiative also involves retrofitting one of Yarwun’s four calciners, enabling it to operate with a hydrogen burner when needed.
The Pilbara Renewables Project
Rio Tinto’s Pilbara Renewables Project features the world’s largest microgrids supported by a substantial 480-megawatt gas-based power capacity. Located strategically in an area with consistent sun and strong nighttime winds, it maximises renewable energy harnessing. Coupled with a Battery Electric Storage System, the plant is set to slash annual CO2 emissions by a substantial 90,000 tonnes – an impact equivalent to the emissions of 6,000 Australian homes each year.
The Importance of Decarbonisation for the Australian Economy
From a business perspective, the significance of Rio Tinto’s initiatives, such as Bio Iron and the Pilbara Renewables Project, is immense. These endeavours contribute to transforming Australia from a traditional “dig and ship” nation into a green steel exporter. Decarbonisation is imperative, especially considering that iron ore exports accounted for a substantial $130 billion in export dollars last year, representing the largest avenue for exports in Australia and serving as the backbone of the nation’s economy. The steel industry’s global shift towards decarbonisation makes it crucial to position Australian iron ore at the forefront of this evolving landscape, ensuring competitiveness and sustainability in the future market. Rio Tinto’s commitment to these changes aligns with both environmental responsibilities and the economic interests of Australia on a large scale.
The imperative to decarbonise the Australian mining industry is rooted in its role as a leading global producer of critical mineral substances. As Rio Tinto and BHP, the mining giants profiting substantially from this sector, collectively invest in initiatives such as the Electric Smelting Furnace (ESF) pilot plant they encourage other industry bodies to do the same. These ventures aim not only to align with the Paris Agreement’s climate objectives but also to propel Australia from a conventional resource exporter to a green steel exporter. With the steel industry contributing 8% of the world’s total carbon emissions, the need for change is obvious. Such, decarbonisation methods, from Bio Iron and the Pilbara Renewables Project to the BlueSmelting process and the Yarwun Hydrogen Calcination Pilot Project, underscore the industry’s commitment to sustainability.
Sources:
Rio Tinto, BHP, ABC
