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文献提出的钙镁连续络合滴定法,是在硼砂介质中选用百里酚酞络合剂作指示剂,用Pb(No_3)2溶液回滴过量的EGTA测定钙,而后加氨水用DCTA连续滴定镁,是在钙镁比(1:30)范围较小的纯溶液中进行的试验。镁量高,虽有硼砂存在,加氨水仍有氢氧化镁沉淀析出,妨碍镁的准确测定。我们选用氨性缓冲介质中进行钙镁的连续络合滴定,镁量高达200mg电不发生沉淀。方法应用于石灰石、白云石、菱镁矿、硅藻土、水泥、镁沙、矿石等多种材料的测定。硅酸加KF解聚,铁、铝、锰、钛、铜、钴、镍等共存的干扰元素,用酒石酸钾钠、三乙醇胺、乙二胺联合掩蔽。一试剂
The proposed continuous calcium and magnesium complexation titration method uses thymolphthalein complexing agent as an indicator in borax medium, titrating excess amount of EGTA with Pb (No_3) 2 solution to measure calcium, and then adding ammonia to continuously titrate magnesium with DCTA , Is a test carried out in a relatively small range of pure calcium to magnesium ratio (1:30). Magnesium content is high, although the presence of borax, magnesium hydroxide precipitation still precipitation, hinder the accurate determination of magnesium. We use ammonia buffer medium for continuous complexometric titration of calcium and magnesium, magnesium up to 200mg does not occur precipitation. The method is applied to the determination of limestone, dolomite, magnesite, diatomite, cement, magnesia, ore and other materials. KF depolymerization with silicic acid, interference elements such as iron, aluminum, manganese, titanium, copper, cobalt and nickel coexisted with potassium sodium tartrate, triethanolamine and ethylenediamine. A reagent