Calcination process for lime decarbonisation

Adam Vincent \ April 26, 2022
Lime, one of the most vital minerals used on Earth

Lime is amongst 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[1]day lives. 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.

Lime refers to products derived from burnt (calcined) limestone, such as quicklime and hydrated “slaked” lime. Limestone is nearly half CO2 by weight. The CO2, which is trapped in the rock, is released when making 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.

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.

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.

“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.”

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 graphics above). 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.

“Once tested and scaled up, Calix’s LEILAC technology should reduce the cost 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

“The current objective facing the lime industry and governments is threefold: 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

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, thus 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.

After the successful commissioning of a world-first pilot plant (LEILAC-1) in 2019, scale up of the technology will be demonstrated on LEILAC-2, where a 4-reactor module array is scheduled to be built by early 2024, with the aim to capture the CO2 from cement and lime processing in a suitable condition for storage.

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 Calix’s 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.

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.

RELATED insights


  • Hidden
  • Hidden
  • This field is for validation purposes and should be left unchanged.