Enabling zero emissions smelter grade alumina with electric calcination.

Alumina mine
Alumina open air mine

Opportunity & challenges

The production of aluminium, a critical metal for many technologies, is amongst the most energy-intensive of industrial processes and contributes ~2% of global CO₂ emissions.

Global decarbonisation goals, energy security and price pressures are combining to create significant headwinds for an industry heavily reliant on fossil fuels.

Regulatory pressure, including carbon pricing and carbon border adjustment mechanisms, as well as environmental, social and governance standards require urgent decarbonisation solutions. Additionally, geopolitical risks and conflicts are destabilising supplies and increasing prices of natural gas.

A clean, sustainable and future-proof pathway for the inherently energy-intensive alumina industry to transition to lower cost, lower emissions and lower risk energy inputs is required.

Opportunity & challenges

The electrification of industrial heating can decouple energy and carbon intensity, enabling energy-intensive processes to reduce and eliminate carbon dioxide emissions.

In line with global net-zero commitments, electrification can eliminate the alumina industry’s carbon emissions entirely by enabling 100% use of renewable energy inputs.

Electrification can also reduce costs, swapping volatile supplies of fossil fuels for increasingly low cost local renewable generation, and increasing efficiency by removing combustion and enabling steam recycling. 

Our solution

Calix’s Zero Emissions Alumina (ZEAL) technology is a unique, indirectly heated electric calciner designed to provide the lowest cost, lowest emissions and highest efficiency solution for smelter grade alumina calcination.

Ideally suited to renewable energy sources and grid-load balancing applications, ZEAL builds upon many years of development of Calix’s core platform technology to replace inefficient and carbon-intensive combustion processes with clean, efficient and precise electric calcination.

In addition to enabling zero scope 1 emissions, Calix’s ZEAL technology aims to deliver the lowest cost calcination solution to the industry through the elimination of fuel and combustion exhaust, elimination of hard face refractory and through the use of steam recycling.

Alumina plant with solar panels
Key features & benefits


Calix’s ZEAL technology uses clean and precise electric heating. It is compatible with intermittent renewable energy sources, flexible operations and power generation response to improve energy security and deliver more cost-effective operations.

Emissions reduction

By replacing combustion and fossil fuels with electric heating, Calix’s ZEAL technology can deliver a 100% reduction in scope 1 emissions by enabling the whole refinery to be powered by locally sourced and renewably generated electricity.

Higher efficiency

Calix’s ZEAL technology uses a first principles approach to deliver best in industry energy efficiency. Avoiding the combustion exhaust gas stream and creating a pure steam stream that can recover and recycle energy is expected to enable approximately 10% reduction in energy intensity of alumina calcination.

Lower cost

Efficient electric heating through Calix’s ZEAL technology is designed to deliver lower operating costs than natural gas, hydrogen or fuel oil.

Improved product quality

Indirect heating enables low particle velocity and precise heating through the calciner. This unique approach can help reduce particle breakage and the formation of alpha alumina, in addition to delivering a premium low-carbon alumina product.

Lower maintenance

The elimination of hard face refractory lining helps reduce maintenance requirements, downtime and cost.


Electric calcination provides a low-cost and future-proof pathway for the alumina industry to reach net zero. It can enable alumina producers to avoid carbon taxes and tariffs, and support national and international decarbonisation targets.

Local benefits

Electrification can help reduce fugitive dust emissions by eliminating the combustion exhaust and recycling steam produced during calcination. In this way, electrification can improve local environmental outcomes, in addition to providing a sustainable pathway for local jobs and manufacturing, and supporting the integration of local renewable generation into the electricity grid.


Fast-tracking commercialisation

Calix has successfully completed pilot scale testing of ZEAL. Feasibility studies are underway for both a 40T/hr demonstration plant and full-scale Calix ZEAL calciners.

Partnering for the planet

Through strong global partnerships and collaboration with industry, academia and governments, Calix is accelerating the development and commercialisation of its core platform technology to urgently solve some of humanity’s greatest challenges. We recognise and thank each of our partners for their vital contributions.

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