This project presents a transformative approach to decarbonising Portland and alternative cement systems by redesigning the most emission-intensive stage—calcination—into a simultaneous carbon conversion and resource recovery process. Conventional cement production releases significant CO₂ both from limestone decomposition (CaCO₃ → CaO + CO₂) and fossil fuel combustion, contributing roughly 8% of global emissions. The proposed concept introduces waste plastics, biomass, and other organic waste streams directly into the calcination environment as chemical feedstocks rather than fuels. Under high-temperature conditions, these materials undergo pyrolysis and gasification, creating a reducing atmosphere that suppresses CO₂ release and promotes its conversion into value-added products such as hydrogen and syngas (H₂ + CO). A key innovation is the elimination of external catalysts: the calcination intermediates (CaO/MgO systems) act as in situ catalysts, enabling carbon conversion reactions (e.g., dry reforming and methane cracking) while avoiding carbon fouling. This integrated strategy simultaneously addresses cement decarbonisation, plastic waste management, and clean energy generation, positioning cement kilns as circular processing hubs rather than purely emission sources.
Aim
The overarching aim of the project is to develop a fundamentally new cement manufacturing paradigm that minimises greenhouse gas emissions while maximising resource recovery and energy generation. Specifically, the project seeks to decarbonise Portland and alternative cement systems by suppressing CO₂ emissions at source during calcination rather than relying on downstream capture technologies. A second aim is to demonstrate the feasibility of converting emissions (CO₂ and CH₄) into hydrogen-rich gas streams within the same process environment, thereby aligning cement production with the emerging hydrogen economy. Additionally, the project aims to establish cement kilns as platforms for feedstock recycling of challenging waste streams—including mixed plastics, biomass residues, tyres, and silicones—thus supporting circular economy pathways. A further aim is to validate that the inherent chemistry of CaCO₃–CaO and MgCO₃–MgO systems can serve catalytic functions, eliminating the need for expensive and deactivation-prone external catalysts. Collectively, these aims target a step-change process capable of delivering deep decarbonisation, waste valorisation, and energy co-production in a single integrated operation.
Objectives
To achieve these aims, the project is structured around several specific objectives. First, it investigates the calcination behaviour of calcium and magnesium carbonates in the presence of plastics and biomass, with a focus on quantifying reductions in CO₂ and CH₄ emissions under varying temperatures and feedstock ratios. Second, it evaluates the in situ carbon conversion mechanisms, including dry reforming, methane cracking, and water–gas reactions, to understand how CO₂ and CH₄ are transformed into hydrogen and syngas without external catalysts. Third, the project aims to determine optimal process conditions—such as temperature, plastic-to-biomass ratios, and carbonate composition—that maximise hydrogen production while suppressing carbon formation and catalyst deactivation. Fourth, it characterises the catalytic role of calcine intermediates (CaO/MgO), including their surface properties, reactivity, and resistance to soot formation. Fifth, the project explores the utilisation of specific waste streams (e.g., halogenated plastics, tyres, and silicone wastes) to assess their compatibility, emission behaviour, and potential contributions to clinker chemistry (e.g., silica substitution). Finally, the project seeks to generate a conceptual framework for scaling the process to industrial cement kilns, including integration with existing clinker production routes and evaluation of potential environmental and operational benefits.
Significance
The significance of this project lies in its ability to address three major global challenges simultaneously: climate change, waste management, and sustainable energy production. By directly targeting calcination emissions—which account for the majority of cement-related CO₂—the proposed approach offers a more effective alternative to conventional mitigation strategies such as carbon capture and storage, which are often energy-intensive and costly. The demonstrated potential for up to ~99% CO₂ reduction highlights the transformative impact this concept could have on the cement sector’s decarbonisation trajectory. From a circular economy perspective, the utilisation of mixed plastics, biomass, and other difficult-to-recycle wastes as chemical feedstocks provides a high-value pathway for waste valorisation, reducing landfill and environmental pollution while recovering embedded carbon, hydrogen, and silicon resources. The elimination of external catalysts significantly enhances economic feasibility and operational robustness by avoiding issues of catalyst poisoning, fouling, and replacement costs. Furthermore, the simultaneous generation of hydrogen and syngas introduces new revenue streams and aligns cement manufacturing with future low-carbon energy systems. Beyond cement, the process has broader applicability to other high-temperature industries such as iron and steelmaking. Overall, the project represents a paradigm shift from emissions-intensive industrial processing to integrated systems that convert waste and emissions into useful resources, supporting both net-zero goals and industrial sustainability.
Ideal Candidate
The ideal PhD applicant should have a strong background in chemical, materials, or metallurgical engineering, with knowledge of thermochemical processes, reaction engineering, and high-temperature systems. Experience in carbon conversion, gasification/pyrolysis, or cement/mineral processing is highly desirable. The candidate should demonstrate proficiency in experimental design and data analysis, with skills in characterisation techniques (e.g., XRD, gas analysis). Programming (Python/Matlab) and modelling capabilities are advantageous. A strong interest in decarbonisation, circular economy, and sustainable process development, along with the ability to work independently and collaboratively, is essential. Additionally, the applicants should meet the eligibility criteria for entry into a PhD program at Curtin University.
This project is open to International and Domestic applicants.
Scholarship
If you are identified as the preferred candidate for this project, you may be considered for an RTP scholarship.
Enquires and How to Apply
For enquires about this opportunity contact Dr Sheila Devasahayam at Sheila.Devasahayam@curtin.edu.au
To formally apply submit an Expression of Interest to Dr Sheila Devasahayam during the Central Scholarship round (July 1st – July 31st 2026)