实践教学创新——钙检测法的改进

Practice Education Reform——The Improvement of Calcium Detection

对于复杂矿石样品中Ca^(2+)的含量,常规方法难以实现安全、简便的测量。有鉴于此,我们以HF/HCl混合消解矿石样品,采用饱和Na_2CO_3将消解产生的难溶CaF_2转化为CaCO_3;随后,以稀盐酸溶解CaCO_3释放出Ca^(2+),以EDTA滴定其准确含量。该方法安全、便捷,具有良好的重现性、可靠性:相对标准偏差0.052%,加标回收率98.9%~99.8%。这一研究过程有助于提升学生的化学实践创新能力。

It’s difficult to detect Ca2＋in complicated mineral samples with a simple and safe chemical method. The mineral samples in the mixture solution of HF-HCl were digested,and the formed precipitate of CaF2 to CaCO3 with saturated solution of Na2CO3 was translated. These CaCO3 could be dissolved easily in hydrochloric solution to release Ca2＋,following an accurate titration with EDTA. The safety and convenience of this improved Ca2＋detection method was encouraging with a relative standard deviation of 0. 052% and a recovery of 98. 9% 99. 8%. This investigation was beneficial to develop the students’ innovation ability in chemistry.