Synergistic Recovery of FePO₄ from Bauxite Residue and Steel Making Slag for Lithium-Ion Battery Cathodes

Jointly Funded by the Bilateral Mobility Program between NTNU and IIT Madras

This ongoing joint mobility project, funded through the Joint-Funded Bilateral Mobility Programme (JFBMP) between IIT Madras and NTNU, brings together the groups of Prof. Ranjit Bauri (IIT Madras, Metallurgical and Materials Engineering) and Assoc. Prof. Sulalit Bandyopadhyay (NTNU, Chemical Engineering) to develop a closed-loop, green process for producing lithium iron phosphate (LFP) battery precursors from industrial waste. The project valorizes bauxite residue and steel-making slag — two abundant metallurgical by-products rich in iron and phosphorus respectively — as a sustainable, low-cost alternative source of FePO₄ for LFP cathode production, addressing the growing demand for critical battery materials.

The work combines hydrometallurgical and pyrometallurgical approaches across raw material characterization, pre-treatment, and extraction, with IIT Madras leading materials characterization and pre-treatment while NTNU develops the hydrometallurgical process for leaching, purification, and precipitation of battery precursors. To date, the NTNU team has characterized LFP black mass feedstock, optimized acid leaching conditions, and demonstrated successful precipitation of FePO₄ from leach solutions using solvent extraction, with ongoing work to improve product purity. The final project stage will focus on resynthesizing LFP cathode material from the recovered precursors and benchmarking its electrochemical performance against commercial LFP.

Running from February 2025 to July 2026, the project has supported active mobility between the two institutions: Prof. Ranjit Bauri visited NTNU in June 2025 for project meetings, laboratory visits, and a guest lecture on waste-to-energy approaches in battery technology, while project PI Erik Prasetyo travelled from NTNU to IIT Madras, and PhD candidate Don George Kurian from IIT Madras spent 10 days at NTNU. This exchange builds on a strong existing partnership between the two institutions in battery recycling research and is expected to produce several scientific publications while laying the groundwork for future joint funding applications in critical materials recovery.