Calix LEILAC technology can significantly reduce the impact of lime production on the environment through carbon capture and other innovative technologies.

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In this “deep dive” into one of our businesses, we explore why lime is a major contributor to CO2, and how Calix’s LEILAC (Low Emissions Intensity Lime and Cement) carbon capture technology can help significantly reduce lime’s impact on the environment. With an expected global market worth of $US59.5B by 2026, lime is an intrinsic mineral with scores of applications.


Lime, one of the most vital minerals used on earth

Lime is among the oldest and most important materials used on earth and an essential element in global civilisation, yet most of us don’t know the vital role it plays in our day-to-day lives.

A calcium-containing inorganic mineral, lime is also commonly known as “quicklime” (calcium oxide) and “slaked lime” (calcium hydroxide).

Typical uses for lime include:

  • In our homes – lime is used to make everyday household products such as dry bleaches, dyes, lawn and garden neutralisers, masonry, mortar, paint, paper, pharmaceuticals, plaster and stucco, sugar, table salt, toothpaste and corn flour.
  • In our communities – for agricultural liming, apple storage, asphalt, sewage treatment and water treatment.
  • For the preservation of our environment – in mine waste water drainage treatment, air pollutant abatement, epidemic diseases control, remediation and wastewater treatment.
  • In industries – for making steel, alumina, barium, glass, lead, lithium, magnesium, nickel, petroleum refining, silver, sodium alkali, solar-grade silica, uranium, wood pulp and zinc.

With such ubiquitous usage, the global lime market reached a value of around $US 41.93 billion in 2020 and is expected to reach $US 51.04 billion by 2028. The high maturity markets in terms of usage include North America and Europe, while markets with high growth potential include South America, the Middle East, Africa and Asia Pacific.

The three leading lime producing countries in the world as of 2020 were China with production volumes of 300 million metric tons, and the United States and India both with production volumes of 16 million metric tons.

The fastest growing use of lime is in environmental applications, where lime is used to comply with air, drinking water, wastewater, and help industries solid waste regulations.

What is Lime?

Lime refers to products derived from burnt (calcined) limestone, such as quicklime and hydrated “slaked” lime. Limestone is a naturally occurring and abundant sedimentary rock consisting of high levels of calcium and/or magnesium carbonate, and/or dolomite (calcium and magnesium carbonate), along with small amounts of other minerals. It is extracted from quarries and underground mines all over the world.

Lime production comprises various processes:

  1. Quarrying of raw limestone, crushing and sizing.
  2. Calcining (burning) limestone in a kiln or calciner.
  3. Processing the lime further by hydrating, mixing with water if necessary (Not all lime is hydrated or “slaked” – much is sold as quicklime, or unhydrated calcium oxide).
  4. Transfer, storage, and handling operations

The lime industry

The market is expected to grow at a CAGR of 5.87% in the forecast period of 2021-2026 to reach a volume of 543 MMT by 2026.

The Asia Pacific is the leading region in terms of production, boosted by the rapidly growing construction industry in the region, especially China and India. The region also has significant demand growth for the steel industry, which in turn is boosting the demand for lime.

Lhoist, a key partner in helping develop Calix’s LEILAC technology, is the world leading supplier of high-quality lime, dolime and minerals, with a vast experience in material characterisation as well as the development of new products and processes. It serves industries like steel, environmental, building and civil engineering, pulp and paper, and agriculture industries.

“Once tested in and scaled up, Calix’s LEILAC Technology should reduce the costs of carbon capture considerably and accelerate the deployment in the lime industry – enabling society to continue to benefit from this vital product without negatively impacting the environment.” Ziad Habib, Global Director – Manufacturing Process Innovation, Lhoist


Other prominent players in the lime market include:

  • Carmeuse Group
  • Graymont Limited
  • Mississippi Lime Company
  • Nordkalk Corporation
  • Ognyanovo K JSC
  • Sigma Minerals Lt

One tonne of CO2 is equivalent to:




Lime production and the climate challenge

The latest Intergovernmental Panel on Climate Change (6th Assessment) Report stated that it is now unequivocal that human influence, primarily through the production of greenhouse gases such as carbon dioxide, is causing widespread and rapid changes to the climate. Some of the consequences of increased greenhouse gases such as CO2 are likely to be:

  • A warmer earth
  • More evaporation and more precipitation
  • Warmer oceans and reduced ice sheets leading to sea level rise
  • Negative effect on crop yields and food security.

The average annual CO2 emission or carbon footprint of one person in the developed world is typically between 17 tonnes (Australia) and 4.3 tonnes (Sweden) per year while the global average is closer to 4.7* tonnes. To have the best chance of avoiding a two degree rise in global temperatures, the global average personal carbon footprint needs to reach zero by 2050. To achieve this, all sectors of society must deliver emission reductions and governments are taking actions to this effect. For example, the UK Government became the first major economy to commit to net zero CO2 by 2050 in June 2019 and is heavily supporting decarbonisation efforts through funding under the UK Department of Business, Energy and Industrial Strategy £1b Net Zero Innovation Portfolio. The European Union in 2021 unveiled a plan to slash its carbon emissions by 55 per cent before 2030 and impose border tariffs on countries, including Australia, that do not have some form of carbon price.

“By acting now,” said European Commission President Ursula von der Leyen in mid-July, “we can … choose a better, healthier and more prosperous way for the future.”

A Technology that is available now

As environmental regulations toughen, and shareholders and stakeholders place increasing pressure on companies to reduce greenhouse gas emissions, lime producers need solutions quickly to help mitigate their CO2 emissions.

Calix’s LEILAC (“Low Emissions Intensity Lime and Cement”) Technology is available now to efficiently separate the CO2 emitted in lime production.

Calix’s LEILAC Technology captures the process CO2 emissions that are generated when limestone is heated (see “Lime and CO2”, page 5). These emissions are unavoidable regardless of the fuel type and can constitute up to 75 per cent of CO2 emissions from a lime plant. The remainder comes from burning fuel.

Further advances in Calix’s LEILAC Technology, such as the ability to electrify the whole of the heating requirement, and power it from renewable energy, means that zero-emissions lime manufacturing can be achieved.

The current objective facing the lime industry and governments is threefold: to maintain economic prosperity, meet lime market demand, while dramatically lowering CO2 emissions. Calix (LEILAC) aims to meet this global challenge as quickly as possible.”

Adam Vincent, General Manager Lime Decarbonisation


Overcoming challenges

While there are multiple kiln types in use worldwide, not only has Calix’s LEILAC Technology demonstrated it can capture CO2 during the lime burning process, but it can also be retrofitted to existing plants and is technically available.

Governments and heavy-use lime industries are beginning to acknowledge the significant environmental problems associated with traditional kilns and introduce incentives to clean up the manufacturing process.

Establishing the funding and partnerships needed for sustainable full-scale calciner plants for lime is a challenge. Calix has a proven track record of winning government and industry funding for several pilot and demonstration plants. These plants and their trials have proven successful and with the use of renewable electricity, lime manufacturing can achieve near-zero emissions, offering an attractive vision of the future to operators and funders alike.

Another challenge is ensuring the captured CO2 has a final destination. Calix is working with partners to identify suitable transport, storage and/or utilisation options so that the climate benefits of Calix’s LEILAC Technology are fully realised.

Calix’s LEILAC Technology can help address one of the goals and targets from the UN’s 2030 Agenda for Sustainable Development: Goal 9-Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation.

LEILAC: The Calix Technology for lime

Calix’s LEILAC Technology involves grinding limestone to an average size of ~around 1/10th to 1/100th of a millimeter and then ‘flash’ heating the material in an externally heated reactor over a short period of time, and in the process converting the particles to lime. Specially selected steels allow the process temperature to reach in excess of 900 °C, which is required for the reaction. The evolved gas is high purity CO2, which can be captured and used or stored.

Calix built its first commercial scale plant in 2012, located in Bacchus Marsh, Victoria, Australia. Its design purpose was to process magnesium carbonate (MgCO3) to magnesium oxide (MgO). The plant is still in operation having processed 35,000 tonnes and run for over 15,000 hours. It runs in campaign mode and has been cycled approximately 200 times. No major defects or deterioration in performance have been recorded.

In 2015 Calix led a successful application to the EU Horizon2020 fund to build a Calix demonstrator plant (in Lixhe, Belgium) for the processing of lime and cement – Project LEILAC 1 (Low Emissions Intensity Lime And Cement). The main scale up challenge for the design was the higher operating temperatures required for heating the limestone compared to magnesium carbonate. LEILAC 1 was successfully commissioned in 2019 having been built on time and on budget. LEILAC 1 proved that it was technically feasible to produce lime in a Calix reactor. The scale of the LEILAC plant, at 3-5 tonnes per hour of lime, is the equivalent of a small commercial lime plant.

In 2019 Calix again led a successful application to the H2020 program for the construction of a scaled-up Calix calciner for processing both cement and lime – Project LEILAC 2. This project will extend learnings from LEILAC 1 to scale the process by a multiple of 4 and aim to capture the CO2 in a suitable condition for storage, with construction scheduled to be completed by the end of 2023.

Meanwhile, Calix has also commissioned and is operating its first all-electric calciner, designed for the development of advanced battery materials where the need for precision control of the process conditions is critical for electrochemical performance.

More recently, and on the back of the knowledge built through years of research and development, Calix has teamed up with several companies to undergo feasibility and engineering studies for the development of Calix lime calciners with carbon dioxide capture capabilities.

↑ Schematic of a single calciner lime plant producing 40,000 tonnes per year of lime and 25,000 tonnes per year of CO2.

The LEILAC technology has the potential to enable the cement and lime industries to efficiently capture their process emissions on an industrial scale. The pilot project in Hannover is one of several promising CO2 capture technologies that we are currently testing at full speed within the HeidelbergCement Group.

HeidelbergCement’s Chairman of the Managing Board Dominik von Achten

The R&D undertaken by Calix and its partners helps to meet one of the UN’s 2030 Agenda for Sustainable Development goals in upgrading the technological capabilities of industrial sectors and encouraging innovation.
SDG Target 9.4: Upgrade infrastructure and retrofit industries to make them sustainable

One of the UN’s Sustainable Development goals (No. 13) is to take urgent action to combat climate change and its impacts. Calix is proud to work with and contribute to Australian and European governments and industries to address this issue by way of, for example:

  • The LEILAC projects, which are supported by the European Union’s Horizon 2020 research and innovation programme, and also an External Advisory Board formed by CEMBUREAU (the European Cement Association), the European Cement Research Academy (ECRA), the Global Cement and Concrete Association (GCCA) and the European Lime Association (EuLA).
  • The HILT CRC (Heavy Industry Low-carbon Transition Cooperative Research Centre), which aims to reduce the carbon emissions of Australia’s heavy industrial processes. Calix is a key partner in this $210 million project with a recent $39 million contribution from the Australian Government

Looking ahead

The next stage of advancement for the processing of lime will focus on several key areas including maximising efficiency, scale up of throughput, testing of solid fuels, testing of alternate gaseous fuels such as hydrogen, scale up of the electric calciner for lime, fuel side CO2 capture options and optimising CO2 clean-up and compression. The ultimate aim is the production of zero CO2 lime.

These advancements will be achieved through projects such as LEILAC 2 together with early commercial developments and ongoing research and development. Efficiency improvements are expected to come as recovered energy sources are integrated into the design, such as for pre-heating the raw material. This will be first demonstrated on the LEILAC 1 plant as proof of concept.

Scale up of the technology will also be demonstrated on LEILAC 2, where a 4-reactor module array will be built. The multiple array design will allow for testing of various fuel sources including electricity. Electrification is the next step in thermal mineral processing as the world shifts from fossil fuelled processes to clean, adaptable technologies. The Calix Technology enables this transition.

Many lime plants are located on other industrial sites, such as steel mills where lime is added to the blast furnace to remove impurities from the iron. Other technologies are being developed to reduce and capture CO2 from the main steel plant. Calix’s LEILAC Technology is low cost and fits well into concepts for ‘green’ steel by offering an efficient method of eliminating the emissions from lime manufacturing on-site.

Other examples of processes with dedicated on-site lime plants are paper mills, offering the opportunity of using renewable biomass as a fuel, and soda ash manufacture where both the lime and CO2 are used in the ‘Solvay’ process. For the latter, the high purity of CO2 could greatly benefit the process.

leilac partners

Visit the LEILAC website

Calix is leading a consortium of some of the world’s largest cement and lime companies with the goal of developing a breakthrough carbon capture process that would enable both cement and lime industries to reduce their carbon dioxide (CO2) emissions dramatically.

Partnering for a better world

Other interesting research & development projects


Memorandum of Understanding or (“MOU”) with a leading lime manufacturer

Calix has signed a MOU with Tarmac, UK to conduct feasibility and Front-End Engineering Design (FEED) studies on a UK project covering lime production of around 30kTpa, including demonstration of 20kTpa CO2 capture and the potential for various fuel options such as natural gas, hydrogen and electricity.

The ability to electrify lime production is considered a breakthrough, given many decarbonisation roadmaps have really only factored in commercial electrification as possible after about 2040.

Joint development agreement with Windship Technology

Shipping accounts for around 2.5 percent of global CO2 emissions and could rise to 10 per cent by 2050 if alternative solutions are not implemented.

Windship is developing a low to zero CO2 emissions solution with its wind, solar and drive train solutions, and its exclusive tie-up with Calix will also target the capture of CO2 emissions from the power systems using Calix’s RECAST Technology. RECAST involves the use of zero emissions lime from a Calix LEILAC plant as a sorbent in the exhaust system of a ship’s engine, with the resulting capture reaction adding significant power to the drive train.

Calix and Windship have executed a development agreement to progress this solution to commercial scale on a ship. Given the increasing legislative pressures on shipping emissions, we look forward to working with the industry to develop the technology as quickly as possible.

Other interesting research & development projects

“Lime is one of the most important industrial products globally, and it is great to be developing this partnership with Tarmac UK.”

Phil Hodgson Calix CEO and MD

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