The invention relates to a system and a method for the processing of minerals containing the lanthanide series and the production of rare earth oxides, which allow a completely closed and continuous treatment of the different materials and desorbent agents involved in the process, thus improving the efficiency in the extraction and avoiding environmental risks associated. The method comprising the steps of: reception and conditioning of the raw material; desorption of valuable product through a plurality of mixing and reaction stages in which the raw material is contacted in countercurrent with a stream of desorbent solution; separation of fine solids; precipitation of secondary minerals through the use of a first reactive solution; precipitation of rare earth carbonates through the use of a second reactive solution; and drying and roasting of the rare earth carbonates to obtain rare earth oxides; wherein the method further comprises a secondary process that allows further processing of the residual mineral, and a dewatering and washing step wherein the residual mineral from the desorption step is washed and a lanthanide-containing liquid is recovered.