Method for cascade recovery of lithium and rare earth from rare earth molten salt electrolytic slag

The invention provides a method for stepwise recycling lithium and rare earth from rare earth molten salt electrolytic slag, and belongs to the technical field of metallurgical waste slag treatment and secondary resource recycling. The method comprises the following steps: (1) reacting the rare earth molten salt electrolytic slag with sulfuric acid for leaching to obtain a lithium-containing solution and leaching slag; (2) mixing the leaching residues with an additive, and carrying out low-temperature roasting transformation to obtain a roasted product; (3) the roasted product is subjected to water leaching, and water leaching residues are obtained; (4) the water leaching residues are subjected to acid leaching, a reducing agent is added, and rare earth leaching liquid and leaching residues are obtained; wherein the additive is alkali and activated carbon, and the reducing agent is formaldehyde or hydrogen peroxide. According to the method, ore phase transformation and efficient extraction of the lithium and