Separation and refining method for mixture of uranium and lanthanoids

At first, pH of nitric acid solution containing a mixture of uranium and lanthanoids is controlled to selectively precipitate uranium compounds for filtering uranium compounds. Next, lanthanoids ions are selectively adsorbed and removed from filtrates which are obtained by filtering the uranium compounds by using adsorbents, for example, anionic ion exchange resins. The filtrates after removed with lanthanoids are used for re-dissolving or cleaning of uranium compounds. With such procedures, deposition of lanthanoids to uranium compounds can be prevented upon re-dissolving or cleaning of uranium compounds, for example, ammonium diuranate (ADU). Accordingly, lanthanoids incorporated in uranium compounds can be removed effectively and rapidly. Further, generation of a great amount of liquid wastes can be avoided. (I.N.)