申请人:Agip Nucleare S.p.A.
公开号:US04202793A1
公开(公告)日:1980-05-13
A process for the production of microspheres of thorium oxide, uranium oxide or plutonium oxide and mixtures thereof, containing carbon. The microspheres are prepared by first forming an aqueous alkaline solution of a salt of said metals which will precipitate to a solid form in a concentrated alkaline medium together with an alkaline polymerizable organic monomer and carbon, thereafter dripping this solution into a concentrated alkaline medium wherein metal hydroxide is precipitated out and said monomers polymerized to thereby form said microspheres. The precipitated metal compounds with polymerized monomer and carbon are washed to remove unwanted ions and dried by various methods such as air currents, infrared lamps, high frequency microwaves or preferably by azeotropic distillation whereby the washed particles are dispersed in an organic liquid immiscible with water which is then boiled off. Simple liquids include 1,1,1-trichloroethane, carbontetrachloride and xylene. The particles are then subjected to thermal treatments which vary according to the particular composition and the properties required in the final product. The microspheres obtained according to the process of the invention possess excellent properties of high density, good homogeneity, and high tensile strength and are useful as fuel for high temperature gas-cooled nuclear reactors. In a preferred embodiment, uranyl nitrate is mixed with acrolein in dilute ammonia solution to which carbon is added and the solution dripped into a concentrated alkaline medium, and the microspheres thereby formed washed with water, dried by azeotropic distillation with an organic liquid, and thermally cycled.
一种用于制备含碳的氧化钍、氧化铀或氧化钚及其混合物的微球的方法。首先形成一种含有所述金属盐的碱性水溶液,该金属盐将在浓缩的碱性介质中沉淀为固态形式,与碱性可聚合有机单体和碳混合,然后将该溶液滴入浓缩的碱性介质中,其中金属羟化物被沉淀出来,所述单体被聚合以形成所述微球。沉淀的金属化合物与聚合单体和碳被洗涤以去除不需要的离子,并通过各种方法进行干燥,例如空气流、红外灯、高频微波或最好的方法是共沸蒸馏,其中洗涤的颗粒被分散在与水不相容的有机液体中,然后将其沸腾干燥。简单的液体包括1,1,1-三氯乙烷、四氯化碳和二甲苯。然后,微球经过热处理,根据特定组合物和所需的最终产品性质而变化。根据本发明的方法获得的微球具有高密度、良好的均匀性和高拉伸强度等优良性能,并可用作高温气冷核反应堆的燃料。在一种首选实施例中,尿酰硝酸盐与丙烯醛混合在稀氨水溶液中,加入碳,然后将溶液滴入浓缩的碱性介质中,由此形成微球,用水洗涤,通过有机液体的共沸蒸馏干燥,并进行热循环处理。