Abstract The study described here and carried out jointly by RECUPYL and INERTEC concerns the assessment of the feasibility of a treatment of blast furnace sludge to allow it to be recycled as part of the steel making process. The blast furnace gases result from the reduction of the iron ore. During the extraction of these gases, solid dusts are carried away, which are recovered by the wet process. Ideally, such sludge could be recycled in a blast furnace, owing to their carbon and iron content; but due to their excessive zinc content (and lead content, to a lesser extent), recycling is impeded, and they are discarded to on-site landfills. After initial detailed chemical and mineralogical characterisation of the blast furnace sludge, a process was developed in the laboratory, and partly at “mini-pilot” scale, which has achieved the objective of less than 0.3% zinc in the dry matter. It can be broken down into two phases: a physical pretreatment phase and a second phase of soft etching. This study brought therefore promising results on the feasibility, at laboratory scale, of recycling blast furnace sludge by a hydrometallurgical process, as the first stage in the design of an industrial process.