Eco-Innovation - Ihobe

RECOVERY OF ALUMINIUM BY-PRODUCTS IN THE REFRACTORY SECTOR

Energy-intensive activities, such as steel and aluminium production, use refractory or heat-resistant products as protective linings in furnaces. Refractory products are made from minerals, such as magnesite, graphite, dolomite and bauxite. To produce cast aluminium, bauxite-based refractory castables - or bauxite cast in bricks or other forms - are essential. The EU is highly dependent on imports of these natural resources, including bauxite. The EU imports around half a million tonnes of refractory bauxite each year, mainly from China. EU importers are therefore at the mercy of China's restrictive export policies.

Bauxite could be replaced by an alternative raw material which is obtained from the recycling of salt slag, secondary aluminium oxide. The European aluminium sector produces one million tonnes of salt slag each year from the secondary smelting of scrap and other aluminium waste. Salt slag contains salts, aluminium oxide, aluminium metal and impurities and is classified as hazardous waste in the EU. The recycling process allows for the recovery of different products, including metal oxides, with an aluminium content of 60-70% in weight, which becomes an alternative to bauxite after undergoing a transformation process.

COLLABORATORS

The LIFE BAUXAL-II project, led by BEFESA, has built a prototype demonstrator with the capacity to treat 650 t/year to carry out an innovative process to transform secondary aluminium oxide, obtained as a by-product of the recycling of aluminium salt slag, into a refractory aggregate, known as BAUXAL, which can be used as the basis for INSERTEC's development of new refractory masses. It will be an appropriate substitute for refractory grade bauxites and its production will therefore reduce the EU's dependence on bauxite imports. The project will demonstrate resource efficiency and contribute to the implementation of the circular economy policy by replacing natural minerals with a secondary material derived from a recycling process.

The expected results include recovering 1,000 tonnes of salt slag, producing at least 650 tonnes of refined secondary aluminium oxide, REFINAL, which will subsequently be demonstrated in different aluminium, steel and iron applications in the form of 200 tonnes of BAUXAL refractory aggregate.

The aim is also to create a defined European target market and a business plan for BAUXAL. BEFESA manages 600,000 tonnes of salt slag each year, so the success of this project and its transformation into BAUXAL refractory aggregate would reduce EU imports of refractory-grade bauxite by 43%.

IHOBE has contributed to the design of LIFE BAUXAL-II in the integration of the life cycle approach in the project, as well as in the promotion and transfer of results.