The process described is utilized for the production of mixed rare earth oxides (REOs) from ion-adsorption clays found in Southern China. These oxides are subsequently used in various high-tech industries such as electronics, renewable energy technology, and aerospace. The REOs produced through this process are of 90-92% purity and serve as critical components in manufacturing permanent magnets, catalytic converters, and other specialized applications where rare earth elements are essential. When utilizing this dataset, ensure that the system boundary excludes downstream processes such as solvent extraction and metal production. Use this data for attributional modeling purposes and apply economic allocation for multi-product processes. Be aware that the data sources are varied, including Chinese literature and expert communications. The defined functional unit for the assessment is the production of 1 kg of mixed REOs with a purity of 90-92% through the in-situ leaching method from ion-adsorption clays in Southern China. Incorporate further processing variations, such as separation into light and heavy rare earth elements, as per the specifics of the given site.