Method for recovering and preparing high-purity thorium oxide from rare earth acid feed liquid

The invention provides a method for recovering and preparing high-purity thorium oxide from rare earth acid feed liquid, and relates to the technical field of hydrometallurgy. The thorium element in the rare earth acid feed liquid is extracted by using a multi-stage countercurrent centrifugal extraction technology, so that the thorium element and the rare earth element are efficiently separated; carrying out first washing on the thorium-loaded organic phase obtained by extraction; the obtained thorium-loaded organic phase subjected to impurity removal is subjected to crystallization back extraction, so that the problem of difficulty in solid-liquid separation of an intermediate product in the production process of thorium oxide is solved, and the intermediate product is good in crystal form and high in purity; carrying out second washing on the intermediate product; and roasting the obtained thorium enriched product subjected to impurity removal to obtain the high-purity thorium oxide. The content of ThO2 in