论文部分内容阅读
一、前言关于用EDTA絡合滴定鈣的測定方法,已有許多成熟的文献,但是在大量鋁离子存在下用EDTA絡合滴定鈣的文献却不多。因为在測定螢石和白云灰化岩中的氰化鈣时,一般是采用三氯化鋁溶液溶解氟化鈣的方法,所以,在大量鋁离子存在下用EDTA絡合滴定鈣是值得研究的問題。根据文献介紹,是于試液中加入蔗糖或甘油,在pH>12的条件下,以酸性靛藍和酸性鉻黑藍作指示剂用EDTA絡合滴定鈣。作者按文献所介紹的方法进行过多次試驗,但是所得的滴定終点很不明显,而且易使滴定終点超过等当点許多。經我們試驗:同样的样
I. INTRODUCTION There are many mature literatures on the determination of calcium with EDTA complexation titration, but there is not much literature on the titration of calcium with EDTA in the presence of a large amount of aluminum ions. Calcium trichloride titration with EDTA in the presence of a large amount of aluminum ions is a problem worth investigating because calcium chloride is usually dissolved in aluminum trichloride solution in the determination of calcium cyanide in fluorite and dolomitic ashes . According to the literature, add sucrose or glycerol to the test solution, titrate calcium with EDTA in the condition of pH> 12 with acid indigo and acid chrome blue as indicator. The author conducted many tests according to the methods described in the literature, but the obtained titration end point is not obvious, and the end point of titration is apt to exceed many equivalent points. After our experiment: the same kind