At CETIM we successfully develop technologies for the recovery of critical raw materials
BIORECOVER, the project that we have coordinated and led at our Technological Centre, is coming to an end with ambitious results, as we have managed to recover metals of high economic value such as magnesium and yttrium from waste of different origins.
In 2019 we started a journey from CETIM coordinating and leading an initiative for the recovery of critical raw materials (CPM’s), better known by its English name “Critical Raw Materials”. We are talking about H2020 BIORECOVER, a project that on the 27th of next month will celebrate its final event in Brussels.
It has been five years, marked by the COVID crisis, which further accentuated the need to research this type of materials to avoid depending on imports from countries such as China and South Africa, where almost 100% of rare earths (scandium, yttrium, lanthanum, cerium, neodymium, etc.) and magnesium and platinum group metals (PGM, iridium, platinum, rhodium, ruthenium and palladium), respectively, come from.
The H2020 BIORECOVER project has investigated the sustainable recovery of critical raw materials from different types of waste, in collaboration with 14 partners from multiple disciplines, involving six EU countries and with international cooperation from South Africa.
From CETIM, we have studied bioremediation technologies, in which through the use of bacteria and fungi we have managed to mobilise different types of critical metals present in three primary and secondary sources into a liquid stream. CETIM has also led the integration of the different stages of the new process developed in BIORECOVER, in order to achieve the maximum recovery of three groups of critical raw materials in an effective and selective, sustainable and green way. More specifically, these three critical raw materials are: rare earths present in bauxite waste (mainly yttrium, but also scandium or neodymium), magnesium present in mining waste, and platinum group elements present in catalyst industry waste (platinum, palladium).
To this end, we investigate bioleaching processes using different types of microorganisms, such as bacteria and fungi, selected according to the raw material and the type of metal to be recovered. These biocatalysts are capable of mobilising the metals present in the solid raw material to a solution, through the biological production in situ of different types of acids, without the need to use the acids produced by the chemical industry, which makes this type of process more sustainable, economical and less risky than conventional chemical leaching processes.
In addition to selecting the microorganisms necessary to carry out the bioleaching process, we have also studied the optimisation of the operating conditions (pH, temperature, percentage of residue, etc.) both for the recovery process of the metals present in three of the raw materials (bauxite waste, mineral waste and waste from the catalyst industry), and for the integrated process of recovery of yttrium, magnesium and platinum, present in these raw materials.
In the process of integrating the recovery of Mg present in mineral waste, CETIM has also studied the recovery of magnesium in solution in the form of brucite (magnesium hydroxide) by means of electroprecipitation technology, in this way we manage to recover the metal in a form and purity suitable for its commercialisation.
At the end of these main critical raw material recovery processes, we use the waste streams generated to create cementitious materials. Through the application of alkaline activation technology we manage to obtain geopolymers or alkaline cements, thus taking advantage of the waste generated and avoiding the use of Portland cement, an element with a high carbon footprint.
All this, performing Life Cycle Analysis and Life Cycle Costing of all processes to find the best solution socially, environmentally and economically. We also analyse technological and non-technological risks.
Towards a more sustainable Europe
European research and alliances such as BIORECOVER contribute to generate knowledge of biohydro processes in order to, in the future, be able to greatly reduce the dependence on raw materials essential for the growth and competitiveness of the European Union and thus move towards a greener Europe.
CETIM will continue to work on the development of the necessary technology to guarantee the recovery of critical raw materials, thus promoting sustainable self-production, growth and job creation, as well as improving the competitiveness of the entire value chain of this type of materials.