METHOD OF PRODUCING ACTINIUM-225 AND RADIUM ISOTOPES AND TARGET FOR REALISING SAID METHOD (VERSIONS) Russian patent published in 2009 - IPC G21G1/00 

FIELD: nuclear physics.

SUBSTANCE: invention relates to nuclear technology and radiochemistry and is meant for synthesis and releasing radioactive isotopes for medical purposes. The method of producing actinium-225 involves exposing a target to a high-intensity beam of accelerated charged particles, where the target contains thorium metal in form of one or more solid monoliths with thickness ranging from 2 to 30 mm in a sealed shell, made from material which does not react with thorium and cooling liquid at high thermal and radiation loads and subsequent extraction of radium isotopes and actinium-225 from the exposed thorium. The material of the shell is niobium, high-alloy austenitic steel, hot-rolled molybdenum, and nonporous graphite, coated outside with a protective layer of nickel. Radium-223 and other radium isotopes can be sublimed from molten thorium with addition of lanthanum metal at temperature not below 1100°C, separated from other sublimed products and purified through liquid extraction chromatography using crown ether based sorbents. To extract actinium, exposed thorium metal is dissolved in concentrated nitric acid. Thorium and a range of impurities are extracted using tributylphosphate or a 0.1 to 0.5 M solution of tri-n-octylphosphine oxide in a non-polar organic solvent or 1-5 M solution tributylphosphate in a non-polar organic solvent from an aqueous solution with nitric acid concentration of 3 to 8 M. The aqueous phase, which contains actinium, is evaporated to dryness with addition of concentrated perchloric acid or other oxidising agents. Extraction chromatography is then carried out in a 3 to 8 M solution of nitric acid using a sorbent with carbamoyl phosphine oxide, and actinium is washed with a 3 to 8 M solution of nitric acid.

EFFECT: increased output and radio nuclide purity of radium and actinium-225.

18 cl, 11 dwg