Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ENSUREAL (Integrated cross-sectorial approach for environmentally sustainable and resource-efficient alumina production)

Teaser

The goal of ENSUREAL is to ensure zero waste production of alumina in Europe. This will be done by developing a zero-waste process for alumina production that can handle a wider range of bauxite than the existing process. This new process will minimize the environmental impact...

Summary

The goal of ENSUREAL is to ensure zero waste production of alumina in Europe. This will be done by developing a zero-waste process for alumina production that can handle a wider range of bauxite than the existing process. This new process will minimize the environmental impact of bauxite mining and alumina production.

Global aluminium metal consumption is expected to grow during the coming years. Aluminium metal is produced through electrolysis from aluminium-oxide, also called alumina. Alumina is produced by the Bayer process from bauxite. The Bayer process has as main drawback that it does not utilize all elements in the bauxite ore and thus produces a lot of waste. This waste is called bauxite residue, or red mud because of its red colour. For every kilo of aluminium metal more than 1 kg of red mud is produced. This waste is usually land-filled in large ponds. The problem with red mud will increase during the coming decades as bauxite qualities gradually contain less aluminium and more of the mined material will end up as waste. The ENSUREAL project addresses the production of alumina, through the introduction of a new technology (improved Pedersen process) that enhances the process\' yield and its energy and environmental performance. The increased costs of processing should be balanced with an increase in revenue from the different products, cheaper bauxite resources and no costs for land-filling.

This is being carried out, along with the development of: key valorisation routes, realistic business scenarios based on life cycle and cost analyses and innovation, dissemination and communication strategies.

Work performed

During the first reporting period, most of the efforts have been put into the pyrometallurgical (WP2) and hydrometallurgical (WP3) processes, to ensure that:
- WP1 had enough information to produce a thorough mapping and a strategy for the identification and utilisation of the necessary resources to produce aluminium through the Pedersen process;
- WP4 (the demonstration work package) has the means to upscale and validate the Pedersen process at TRL7 in the end of the project and;
- WP5 will be able to assess the valorisation of ENSUREAL’s grey mud and iron streams, thus contributing to the zero-waste philosophy of ENSUREAL.

Also, processes for innovation, project management, clustering, dissemination and communication have been established and are now known and utilised by all the partners. All these activities and key results will be depicted in the following.

During the first reporting period, WP1 has been focused on identifying exploitable raw materials sources and giving recommendations to reduce EU imports’ dependence. This work package has been fed by WP2 and 3. Within WP1, it has been concluded that karst Mediterranean type bauxites are suitable to be used as input for the Pedersen process. Regarding limestone resources, Europe’s provisions have been deemed considerable, although in-situ production is being taken into account for the ENSUREAL business case scenarios. Moreover, biochar’s use as a coke replacement has been studied. This will be further investigated in WP7, on business case scenarios’ development.

In the scope of WP2, metal and slag materials have been produced at the NTNU/SINTEF labs (200 kg of slag and 20 kg of metal were produced in each experiment), also bauxite pre-reduction using hydrogen experiments were conducted. Biocarbon was successfully used and all materials have been characterised, having the slag produced sent to NTUA for its use in WP3. Metal produced has been sent to Odlewnie for its characterisation in WP5.

WP3 has been focused on maximising the alumina recovering from the slags obtained in WP2 (ensuring a grey mud product that can be characterised by Luvena in WP5 in the next reporting period) and maximising the alumina hydrates’ precipitation from pregnant alkaline solutions.
The slags’ investigations have been focused on the leaching of calcium aluminate slags, starting from synthetic samples and following with the slags obtained in the smelting process within WP2. Due to a highly complex chemistry of the system, risks that could not have been identified beforehand have arisen. NTUA and the partners involved in WP3 are now working in keeping these risks from materialising and optimise the slag leaching along with the precipitation step and WP4’s demo activities. The highest Al2O3 extraction, carried out under the optimum conditions, contained amounts higher than foreseen (16 g/L). Nevertheless, the maximum Al2O3 extraction was ≈70% which lower than expected at this stage.

Based on feedback retrieved from WP1, the sustainability of the Pedersen method has been developed around two regions: Greece and Norway. Furthermore, the LCCA will compare the economic performance of the ENSUREAL project to the state of the art. So far, ITRB has worked on the application of this model for two possible scenarios developed for the processes, which differ in the presence or absence of a pre-reduction phase of bauxite before it enters the electric arc furnace.

The selection of most promising regions for the method has allowed to start an analysis of the business environment for ENSUREAL. The partners have agreed to explore two different scenarios, using different raw materials’ compositions (including bauxite/pre-reduced bauxite and bauxite residue).

Innovation, dissemination and communication strategies have also been put into place. This comprises the use of an innovation radar tool, dedicated innovation workshops at the occasion of each consortium meeting, the usual worksh

Final results

At each step of the process, ENSUREAL’s innovations are going in line with what was expected at the beginning of the project
- For the Iron production (Pyrometallurgical step): biochar has been successfully used for lab and pilot experiments and pre-reduction with hydrogen experiments have been conducted successfully.
- For the alumina production (Hydrometallurgical processing): the next reporting period will contain results in alumina precipitation and calcination;
- For the Grey Mud residue: initial characterization of pig iron and grey mud has been performed for two of the sectors considered (fertilizers and cast-iron production).

Once the mass and energy balanced are fixed, the expected impacts vs Bayer process in terms of energy savings (1.8 GJ/t alumina) and CO2 emissions will be provided by the LCA, which is being carried out by AdMiRIS in WP6.

When it comes to dissemination and communication impacts, they are going as expected as can be seen in the previous section. The organization of a H2020 related forum shall be highlighted as a key event for the ENSUREAL consortium and it is expected to have a continuity for the project duration and beyond.

Website & more info

More info: https://www.ensureal.com/.