Patent Number: 
Section: claims

1. A method for producing 225Ac, comprising:a method (X) for purifying a 226Ra-containing solution, comprising an adsorption step (R1) of allowing a 226Ra ion to adsorb onto a resin carrier having a function of selectively adsorbing a divalent cation by bringing a 226Ra-containing solution (a) into contact with the carrier under an alkaline condition, and an elution step (R2) of eluting the 226Ra ion from the carrier under an acidic condition;a method for producing a 226Ra target, comprising an electrodeposition liquid preparation step (R4) of preparing an electrodeposition liquid by using a purified 226Ra-containing solution (b) obtained by the method (X), and an electrodeposition step (R5) of electrodepositing a 226Ra-containing substance on a substrate by using the electrodeposition liquid; anda step (A1) of irradiating a 226Ra target produced by the method for producing a 226Ra target with at least one kind selected from a charged particle, a photon, and a neutron by using an accelerator to produce 225Ac. 2. The method for producing 225Ac according to claim 1, whereinthe carrier has a divalent cation-exchange group. 3. The method for producing 225Ac according to claim 1, whereinthe carrier has an iminodiacetic acid group. 4. The method for producing 225Ac according to claim 1, the method (X) further comprises a step (R3) of performing anion exchange by passing a solution containing a 226Ra ion eluted in the elution step (R2) through an anion exchange resin. 5. The method for producing 225Ac according to claim 1, whereinthe 226Ra-containing solution (a) is obtained by separating an 225Ac component from a solution in which a 226Ra target irradiated with at least one kind selected from a charged particle, a photon, and a neutron by using an accelerator has been dissolved. 6. The method for producing 225Ac according to claim 1, whereinthe carrier is charged in a tube. 7. The method for producing 225Ac according to claim 1, further comprisinga purification method (Y) comprising the steps:(R6) of allowing a 226Ra ion to adsorb onto a carrier having a function of selectively adsorbing a divalent cation by bringing a 226Ra-containing solution (c) after the electrodeposition step (R5) into contact with the carrier under an alkaline condition; and(R7) of eluting the 226Ra ion from the carrier under an acidic condition, whereina purified 226Ra-containing solution (d) obtained by the purification method (Y) is mixed with the purified 226Ra-containing solution (b), and an electrodeposition liquid is prepared in the electrodeposition liquid preparation step (R4). 8. The method for producing 225Ac according to claim 7, the purification method (Y) further comprises a step(R8) of performing anion exchange by passing a solution containing a 226Ra ion eluted in the elution step (R7) through an anion exchange resin. 9. The method for producing 225Ac according to claim 1, further comprising the steps:(A2) of dissolving the 226Ra target irradiated in the irradiation step (A1); and(A3) of separating a colloidal 225Ac component by alkalizing the solution obtained in the dissolution step (A2).