Result description
It is estimated that ≈170 Mt of Bauxite Residue (BR) are produced worldwide, with ≈5 Mt produced in EU-27 alone, following the hydrometallurgical extraction and refinement of alumina from bauxite via the Bayer process. Only 3% of the annual production is currently utilised in cement, iron production and other applications, whereas the rest of it is landfilled in the proper disposal areas. The cumulative stockpiled level in Europe is >250 Mt (dry matter). European cement contains ≈23% of Supplementary Cementitious Materials (SCMs), i.e. limestone, granulated blast-furnace slags or fly ashes, resulting in a carbon footprint of 667 kg CO2/t cement in 2017. Considering that the development, deployment, and acceptance of relevant innovation for BR valorisation could positively contribute to the circular economy, EU ReActiv project aims to convert BR into an SCM to replace at least 30% of clinker at a much lower cost, resulting in lower carbon footprint cement.
The ReActiv project assumes the development of technologies for the treatment and valorization of bauxite residues. Our results demonstrate that it is possible to valorize Bauxite Residues into active materials to be used as Supplementary Cementitious Materials. In particular, the co-calcination of Bauxite Residues with kaolinic clays and the vitrification of bauxite residues have shown excellent reactivity when blended with cement, by creating a material with pozzolanic and hydraulic activity. Following our proposal, by substituting up to 30 wt.% of the standard cement clinker with the processed BR, we estimate a reduction of global CO2 emissions by up to 30 wt.% in cement formulation while maintaining its key properties. Moreover, it would allow the usage of bauxite residues industrially, which in Europe is estimated to ≈5Mt per year.
Addressing target audiences and expressing needs
- To raise awareness and possibly influence policy
The project requires social support and investment in the scale-up of this solution in alumina production plants, as well as the establishment of a proper regulatory framework which will facilitate the use of Best Available Techniques-bauxite residue (BR). It is noted that cement currently contains ≈23% of Supplementary Cementitious Materials (SCMs), i.e. limestone, granulated blast-furnace slags, and fly ashes. The ReActiv concept intends to transform BR into SCM that results in lower carbon footprint cement while saving landfill space and reducing the dependence on primary-resource markets.
- Public or private funding institutions
- EU and Member State Policy-makers
- Private Investors
R&D, Technology and Innovation aspects
Currently, we have published research exhibiting promising results when using treated bauxite residues as SCMs on the newly formulated SCMs, and developed simulation models of the technology to demonstrate the solution’s applicability. The next step is the installation of pilot plants and legal aspects being pushed forward to bring BR-based SCM as building materials.
Near 5 million tons of bauxite residues (BR) are produced annually in EU-27. With the valorization of this amount, a calculated 2.2 million tons of SCM can be obtained and used in the cement industry. With the substitution of 30% clinker with treated BR, a reduction of CO2 footprint in cement production is estimated to be near 30%. If applied only to 2 million tons/year of cement (1% of Europe’s annual cement production) we evaluate a CO2 reduction of 300,000 tons per year, which includes a yearly decrease of 38000 tons of fuel, and 44 GWh of electricity.
Implementing this solution in several alumina plants that produce bauxite residues with different compositions is a real possibility. Taking into consideration that the ReActiv project brings together 77% of the total European alumina production, together with partners outside Europe, the replication of this solution worldwide is expected. The symbiotic value chain which will be developed between the cement and the alumina sectors, together with already published scientific reports, demonstrate the replicability of the solution and the certainty of absorption of bauxite residues produced by the cement industry.
The economic sustainability of our solution arises from the multiple applications of the extracted materials from bauxite residues. In particular, the treated bauxite residues can be obtained in a continuous process directly on alumina plants. This work associated with the increasing scarcity of other supplementary cementitious materials demonstrates that this solution is sustainable in the long term.
Result submitted to Horizon Results Platform by ADVANCED MINERALS AND RECYCLING INDUSTRIAL SOLUTIONS IKE
