The present invention relates to a desulfurization process of pastel and grids of lead accumulators comprising a carbonation in two steps, a granulometric separation between the two steps followed by specific desulfurization of the large part, a desodification obtaining the conversion of the PbSO.sub.4 contained in the pastel into PbCO.sub.3 which can be easily converted into metallic Pb in an oven by the addition of coal. The system used for the desodification of the large part of the pastel can also be used for the desulfurization of the fine part of the grids.