Iron and steel production is the second largest source of man-made industrial CO2 emissions, responsible for an estimated 2.6 billion tonnes per year, or approximately 7%* of global industrial emissions. Mitigating CO2 emissions from the iron and steel industry will be critical to ensuring we can simultaneously meet our goals for social, economic and environmental sustainability.
Between 80 and 85% of the industry’s CO2 footprint is linked with the production of iron, as 90% of all iron is produced by metallurgical coal- and coke-fuelled blast furnaces, producing nearly 1.8 tonnes of CO2 per tonne of iron produced.
Iron produced via direct reduction of iron ore using a ‘syngas’ of hydrogen and carbon monoxide (made from natural gas) in a shaft furnace is a less CO2-intensive method, at around 0.6 tonnes of CO2 per tonne of iron; however, this process route has traditionally been more expensive, and hence only 10% of the world’s iron is produced by this method. The method requires cheap natural gas, as well as pelletisation of iron ores to prevent fines loss.
Methods to lower the carbon footprint of iron production have started to consider using green hydrogen as the major reductant instead of natural gas and coal. The use of hydrogen in blast furnaces is being tested, but there are limits on the amount of coal it could replace due to a reduction in the conversion rate of iron ore to iron.
Calix’s ZESTY uses green hydrogen in a renewably powered reactor to produce green iron and ultimately, green steel.
ZESTY’s unique, indirect heating approach not only enables efficient electrification, but means hydrogen is not consumed as a fuel, only a reductant, and is easily recycled in the process. This significantly lowers operating temperatures and potentially enables the most efficient and economical use possible of hydrogen.
ZESTY’s ability to handle small particle sizes has the potential to more easily remove impurities compared with other direct reduced iron (DRI) processes, which require pelletised and typically higher grade iron ores.
The ZESTY process produces green iron from multiple ore types for use in either conventional blast furnaces for lower carbon steel products or directly in electric arc furnaces (EAF) for zero emissions steel.the The ZESTY Steel process uses zero emissions lime produced by a Leilac kiln, while the lime can also scrub excess carbon dioxide as well as other pollutants from the exhaust gases.
Source: Climate change and the production of iron and steel. World Steel Association. 2021
With an increasing global population and vast regions of the world experiencing unprecedented levels of growth and prosperity (ie Asia), it is evident that the world will require record levels of urbanisation now and into the future.
According to UNIDO (United nations industrial development organization) a specialised agency of the United Nations, the world is expected to build a New York City equivalent every month for the next 40 years. This level of infrastructure demand will inevitably place a significant strain on the raw material supply chain and lead to more direct and indirect carbon emissions of businesses involved in processing and supplying the raw materials for this infrastructure boom.
Cement is one key ingredient that will be used to satisfy this insatiable demand, but with global carbon emissions of 8% directly related to its processing and production, there is an immediate need to begin decarbonising this process now and introduce new technologies to reduce intense carbon emissions.
Calix has been working with industry to reduce these carbon emissions by developing clinker substitutes that have characteristics on-par with OPC (Original Portland Cement) when utilised as a supplementary cement material (SCM).
The use of calcined clay blends as an SCM is an emerging technology showing promise as a sustainable substitute (e.g. LC3 technology or Limestone Calcined Clay Cement). When calcined clay is manufactured using Calix technology, it is activated so it can be used successfully as an SCM in cement and/or concrete production.
In the Calix Flash indirect heating process, a patented design, the clay particles do not come into direct contact with the heat source. This ensures the following:
The resulting calcined clay product, when used in blends such as LC3 cements (30% clay, 15% lime, 5% gypsum and 50% clinker), exhibits characteristics that are on-par with OPC. In Europe, new building codes incorporate the use of 50% clinker blends and in the US, the ASTM standards for 50% clinker blends are starting to be incorporated.
The use of SCM’s in cement and concrete are crucial in decarbonising the economy and unlocking between US $800 billion to US $1.9 trillion in the green built environment value pool (McKinsey and Company, 2022). Fly ash is one such SCM that has shown to be used satisfactorily in limited clinker substitution but with the shutting down of coal fired power plants across the globe due to increased regulatory pressures and emissions intensiveness, means output will be significantly reduced.
The US Energy and Information Administration (EIA, 2022) has reported that a significant reduction in fly ash production in the US by 30 million short tons (27.7 metric tonnes) is to be expected in 2023 from 2022 alone, which drastically reduces output of this SCM based cement.
Silica fume being another SCM used in cement production has great properties with regards to corrosion resistance to chemicals and high salty environments as experienced in marine environments, but requires specialist attention during construction phases of a project and its clinker substitution content (percentile) is significantly lower than that of clay. By using Calix’s patented electric calciner design for the calcination of clay for SCM based cement, the industry is well on the way to achieving the following goals.
These are important goals if the world is to meet 2050 global emissions targets and to keep the temperature increases to below 2˚C as outlined by the Paris Climate Agreement.
Calix and Pilbara Minerals have executed a formal joint venture agreement for an innovative decarbonised lithium refining project that aims to create a new, high value and low carbon intensity lithium product in the Pilbara. The joint venture follows a successful joint initial scoping study, and a close working relationship built over the past 18 months.
Calix Managing Director and CEO, Phil Hodgson said, “Calix is delighted to formally announce our joint venture agreement with Pilbara Minerals for the development of a sustainable, high value mid-stream lithium product.
“Calix is focused on decarbonising our essential industries, utilising our core technology’s ability to electrify industrial processing, and minimise the waste and CO2 footprint of minerals.”
“We are excited to join forces with Pilbara Minerals and formalise our close working relationship built over the past 18 months. We will apply our combined capabilities to generate a more sustainable and valuable Australian lithium product.”
Pilbara Minerals’ Managing Director and CEO, Dale Henderson agreed, “It’s a great privilege to enter this partnership with Calix. The Mid-stream project has the potential to be a game changer for our industry.
“If successful, we will be able to deliver a superior product to market, that will attract a premium compared to spodumene concentrate, as well as a reduction in Scope 3 emissions within the lithium supply chain.”
The “mid-stream” project aims to produce a superior lithium export product via Calix’s calcination technology for sustainable processing of minerals.
The proposed renewably powered at-mine processing innovation is targeting a refined lithium salt product that greatly reduces the cost, waste, and CO2 footprint of Australian lithium, creating a significantly higher value export product.
The project includes the potential development of a demonstration plant at Pilbara Minerals’ Pilgangoora Project and is supported by A$20m in Australian Government funding announced under the Modern Manufacturing Initiative. A Financial Investment Decision on the proposed demonstration plant is planned before the end of FY23.
Australia currently produces nearly half the world’s lithium, with the global market for lithium carbonate and equivalents projected to grow six times by 2030. Industrial decarbonisation tailwinds also continue to drive demand for renewably powered, low waste processing solutions for the materials of our future economy. A successful “mid-stream” project will enable the joint venture to license the technology to the global spodumene processing industry.