ALUMINA CALCINATION USING RENEWABLE ELECTRICITY FOR ZERO EMISSIONS ALUMINA PRODUCTION

The Calix eAlumina Calciner is an advancement in the field of alumina production, marking a significant departure from conventional methods of calcination. The technology utilizes electricity instead of fossil fuels, allowing it to use cheap and abundant renewable energy sources such as solar and wind power and lower greenhouse gas emissions, in line with grid emissions intensity.
Alumina hydrate sourced from Queensland Alumina Limited (QAL) was processed through a 250 kg/hr pilot scale eAlumina calciner and independently tested at QAL and Calix for quality assurance purposes. The calciner was effective at producing smelter-grade alumina, and also shows potential as a pre-calciner or “gibbsite cooker”, allowing for either partial or full electrification of the traditional calcination process.
Testwork showed that the simplified flow path through the pilot scale calciner resulted in substantially lower particle breakage than gas suspension calcination. By reducing fragmentation, the eAlumina Calciner may provide opportunities for higher yields in Bayer Circuit precipitation process while also delivering more consistent product quality to downstream customers.
The vertical design of the eAlumina Calciner also enables the capture of uncontaminated pure steam released during the calcination process, which can be returned to the Bayer process via Vapour Recompression, improving overall energy efficiency and further reducing greenhouse gas emissions.
The success of the initial testing phase has generated interest in developing the technology further via a larger scale pilot plant (10 – 40 t/hr). The pilot plant will serve as a platform to further explore, validate, and refine the innovative features of the eAlumina Calciner, bringing it closer to full-scale deployment and contributing to the broader industry’s move towards greater efficiency, sustainability, and quality.