化学专业英语翻译4.docVIP

04.GROUPS IIIB—VIIIB ELEMENTS Group I-B includes the elements scandium, yttrium, lanthanum, and actinium1, and the two rare-earth series of fourteen elements each2 —the lanthanide and actinide series. The principal source of these elements is the high gravity river and beach sands built up by a water-sorting process during long periods of geologic time. Monazite sand, which contains a mixture of rare earth phosphates, and an yttrium silicate in a heavy sand are now commercial sources of a number of these scarce elements. B组包括元素钪，钇，镧，和actinium1，和2稀土系列十四each2镧系和锕系元素的系列。这些元素的主要来源是重力高与海滩砂建立起来的water-sorting过程在漫长的地质年代。独居石砂，其中包含一个混合稀土磷酸盐，和一个钇硅酸盐在沉沙现在商业来源的一些这些稀有元素。 Separation of the elements is a difficult chemical operation. The solubilities of their compounds are so nearly alike that a separation by fractional crystallization is laborious and time-consuming. In recent years, ion exchange resins in high columns have proved effective. When certain acids are allowed to flow down slowly through a column containing a resin to which ions of Group III B metals are adsorbed, ions are successively released from the resin3. The resulting solution is removed from the bottom of the column or tower in bands or sections. Successive sections will contain specific ions in the order of release by the resin. For example .lanthanum ion (La3+) is most tightly held to the resin and is the last to be extracted, lutetium ion (Lu3+) is less tightly held and appears in one of the first sections removed. If the solutions are recycled and the acid concentrations carefully controlled, very effective separations can be accomplished. Quantities of all the lanthanide series (except promethium, Pm, which does not exist in nature as a stable isotope) are produced for the chemical market. 分离的组成部分是一个困难的化工操作。溶解度的化合物是几乎一模一样，分离结晶是艰苦和耗时的。近年来，离子交换树脂在高列已证明有效。当某些氨基酸可以缓缓流下一列含有树脂的离子组第三金属离子吸附，先后从resin3。由此产生的解决方案是删除从塔底、塔带或部分。连续的部分将包含特定的离子释放的顺序由树脂。例如。镧离子（La 3 +）是最紧密举行的树脂，是最后被提取，镥离子（lu3+）是不那么严格，出现在第一部分被删除。如果溶液再生和酸浓