The invention concerns a recycling process for recovery of metals from Li-ion batteries. More particularly, an autogeneous process is disclosed for the recovery of Co from Li-ion batteries also containing Al and C, comprising the steps of: —providing a bath furnace equipped with means for 02 injection; —providing a metallurgical charge comprising CaO as a slag former, and Li-ion batteries; —feeding said metallurgical charge to the furnace while injecting O2, whereby at least part of the Co is reduced and collected in a metallic phase; —separating the slag from the metallic phase by tapping; characterized in that the fraction of Li-ion batteries, expressed as weight % of the metallurgical charge, is at least equal to 153%−3.5 (Al %+0.6 C %), Al % and C % being the weight % of Al and C in the batteries, thereby enabling to operate the smelt reduction process in autogeneous conditions. This process possesses advantages over the state of the art process using a shaft furnace, having a large tolerance towards the morphology of the charge, high energy efficiency, and simplified off-gas cleaning requirements.