On 16 March 2023 the EC published the Critical Raw Materials Act (CRMA) setting “benchmarks along the strategic raw materials value chain and for the diversification of EU supplies”. By targeting the domestic processing and refining of lithium – arguably “the most strategic CRM”– LITHOS directly contributes to the 1st and 2nd CRMA benchmarks (10% domestic extraction; 40% domestic processing). LITHOS processes and refines the ores from three “Strategic Projects” in terms of domestic battery-grade LiOH·H2O production: two spodumene-bearing pegmatite cases (Keliber’s deposits in the Kaustinen region, Finland; Savannah’s Barroso Lithium Project, Portugal) and one Rare-Metal Granite (RMG) case (Imerys’ Beauvoir mine in France). LITHOS expands and tailors the existing Keliber & M:O flowsheet, which was developed for regular-grade spodumene ores, so that (1) the cut-off grade for spodumene ores is reduced, resulting in larger Li reserves, while (2) allowing the commercialisation of lower-grade pegmatite and RMG deposits. LITHOS triggers innovations along the value chain – mineral processing, concentrate pre-treatment & hydrometallurgical refining – making it possible to deal with different levels and types of impurities in non-spodumene Li minerals (lepidolite & petalite). LITHOS gives specific attention to closed-loop water systems in the mineral processing (KPI: 90% less water consumption). The overall CO2 emissions of the LITHOS flowsheet will be 50% lower than today’s benchmark (production of spodumene concentrate in Australia & refining in China). This work is enriched by bespoke thermodynamic modelling and digital twins. Supported by FMG & Euromines, LITHOS intends to replicate the LITHOS “responsible mining and refining” concept to the other 24 identified Li-hard-rock deposits in Europe. LITHOS’s meta-objective is to unleash Europe’s full Li-hard-rock ore potential (total: 8.8 Mt Li2O) so as to become self-sufficient by 2030–35 in terms of made-in-Europe LiOH·H2O.