BIORECOVER

The second stage of our BIORECOVER project consists of the pre-treatment of the raw materials to facilitate their treatment. This pre-treatment stage aims at increasing the concentration and accessibility of the CRMs present in the raw material sources by removing interfering components. To do so, our team is experimenting the use of biocatalysts such as the microbial action of fungi or of indigenous bacteria. After testing different biocatalysts on all targeted raw materials, the most efficient pre-treatment process will be validated for each targeted raw material.

During this third stage, the raw materials will undergo a treatment to isolate selected CRMs and obtain the most efficient bioleaching process. Bioleaching is a sustainable extraction process of metals from the samples through the use of living organisms that are able to produce a bioleachate, a solution containing the target metals in the desired chemical species. Various living organisms considered most appropriate to release the selected metals will be tested and evaluated. Further, based on the results of previous characterisation, conditioning and pre-treatment stages (steps 1 & 2), BIORECOVER expects to design the most efficient process to obtain the bioleachate with high recovery, selectivity and purity rates. This biotechnological step in the mobilisation of target CRMs is key to achieving the project’s goal of a 90% extraction rate.

Stage 4 consists of the post-treatment in order to extract the targeted CRMs from the bioleachate used in step 3. It experiments the use of 5 novel and eco-friendly approaches (applied separately or in combination) to ensure a high selectivity of the CRMs recovered (95%), achieving high performance and improved efficiency: - Adsorption by reusable polymeric microcapsules for REE & Pt recovery​ - Biosorption by microalgae for REE, Mg and PGM recovery​ - Biosorption by bacterial cells for REE and PGM​ recovery - Fungal-based biorecovery for Mg​ - Biosorption by proteins for Mg and Pt recovery.

Stage 5 focuses on defining the optimal combination along the different stages to obtain the highest recovery, selectivity, and purity rates for the BIORECOVER process. It aims at developing a BIORECOVER Decision-Making Framework (DMF) that integrates the different treatment stages in a unique tool for easy operation and application. This DMF is a flexible modelling forecasting tool that considers best practices for each targeted CRM. To optimise the process, it identifies the technical performance, health and safety, as well as economic and environmental parameters, while also predicting the metal recovery efficiencies and efforts needed.

Stage 6 tests the quality of the recovered CRMs in high-value end-user applications which include: brake pads, oxygen sensors, high-quality magnesium, salts and sponges for catalysts. It defines the initial requirements for the target CRMs and, further studies the downstream processes to purify or modify the recovered CRMs to reach commercial requirements, ensuring the marketability of the recovered raw materials.

Stage 7 aims to develop strategies to valorise the residual streams generated by the BIORECOVER process while minimising water consumption and wastewater generation. To achieve such a Zero liquid discharge (ZLD) process. A life cycle assessment (LCA) will be conducted to find ways to reduce the generation of waste, wastewater, and emissions within the BIORECOVER process. Further, this step includes a social impact assessment to define social consequences and improve public awareness of this novel bio-technological process.