NTUA: Advancing resource recovery and alloy production

The HAlMan project stands at the forefront of sustainable resource management and alloy production, with the National Technical University of Athens (NTUA)

The HAlMan project stands at the forefront of sustainable resource management and alloy production, with the National Technical University of Athens (NTUA) playing a pivotal role. NTUA’s research arm, Tesmet, is actively engaged in various facets of the project, contributing expertise and innovation to drive its success.

Resource recovery

A key aspect of Tesmet’s involvement lies in resource recovery from slag, a by-product of metal production in the Halman process. Collaborating with Norwegian partners at the Norwegian University of Science and Technology (NTNU), Tesmet is eagerly anticipating the delivery of slag for leaching. This process aims to produce an aluminate solution and a grey mud residue. Notably, from the grey mud residue, Tesmet plans to extract critical raw materials (CRMs), specifically strontium.

Alumina production

The aluminate solution obtained from the leaching process is a valuable resource for alumina production. Tesmet employs precipitation carbonation techniques to precipitate alumina hydrate, utilizing advanced methodologies for optimal efficiency.

Thermodynamic and CFD modelling

Tesmet’s research extends beyond experimental work to encompass thermodynamic and Computational Fluid Dynamics (CFD). The thermodynamic modelling has started utilising results from the leaching experiments (NTNU) and existing data of the carbonation/precipitation step. CFD modelling is performed in cooperation with the Chemical Engineering Department of NTUA. The first model was performed with just water and CO2 gas and was presented at the 14th Panhellenic Chemical Engineering Conference underscoring the project’s academic significance. Furthermore, a scientific article has been submitted on this work and is currently under review. Both the thermodynamic and CFD models developed, serve as invaluable tools for process optimization.

Future directions

Looking ahead, Tesmet plans to expand its CFD modelling of the precipitation reactor efforts by incorporating additional chemical species, enhancing the accuracy of predictions. Moreover, thermodynamic modelling of leaching and precipitation steps is underway, with promising initial results that necessitate further refinement, particularly regarding imposing kinetic barriers as these systems are far from equilibrium.

Alloy production

In addition to resource recovery, Tesmet is actively involved in alloy production. Through simulations with FactSage software, Tesmet explores the production of commercial Al-Mn alloys from metal phases generated in the HAlMan project’s aluminothermic reduction process. Experimental validation of predictions is imminent, marking a significant milestone in alloy development.

Tesmet’s multifaceted contributions to the HAlman project exemplify its commitment to advancing sustainable resource management and alloy production. From innovative resource recovery techniques to high-level modelling and alloy development, NTUA’s team aims to provide significant advancements in the field.

Through collaborative efforts and ongoing research initiatives, NTUA remains at the forefront of transformative innovations, shaping the future of metallurgy and resource utilization within the HAlMan project framework.