【摘要】 <正> 以碳酸鈣、氯化銨混合体,来熔化土壤中鉀矿物的方法[Lawrence Smith(史密司)法]是分析化学上通用了最久的方法之一。这个方法,显然具有分解作用比較彻底的优点,而土壤及岩石中某些原生鉀矿物又为一般酸液所不能溶解。分析化学家在最近20—30年以来,企图用各种混合酸液(特别是氟氫酸——过氯酸——硫酸)来代替史密司的冗长熔化步驟,但是在对待某些富有Al、Ti、Ba等合鉀矿物的土壤时,显然沒有达到完全分解的目的。因此,在土壤的全量分析时,习用了九十年之久的史密司方法,在今天还是被更多还原

【Abstract】 In the original procedure of J. L. Smith’s method for determining potassium in soils, solid ammonium chloride is pulverized with soil sample and then mixed with calcium carbonate. The writers recommend to mix soil and calcium carbonate in advance, and the mixture is moistened with 15% NH₄Cl solution. Experimental results also show that the fusion can be done directly in a muffle of 700℃ without significant volatile of ammonium chloride. Porassium can be determined in a portion of water extract in flame photometer without the previous removal of Ca++ ion. Results show good agreement with the original method.更多还原