【摘要】 研究了以 PAN为指示剂 ,硫酸铜为回滴剂的 EDTA络量法测定铝的终点判别的影响因素 ,并根据试验中所接触到样品组成不同、铝量及干扰离子不同等条件 ,对终点的影响作了进一步探讨 ,得出终点判断依据为 EDTA∶ Cu2 +∶ Al3+之间的摩尔比为 1∶ (0 .2～ 0 .3)∶ (0 .7～ 0 .8)之间 ,且服从 n EDTA=n Cu+n Al更多还原

【Abstract】 It is reported that in the chelatometric titration of aluminum as a major constituent using Cu(Ⅱ) standard solution as back titrant and PAN as indicator, the accurate visual detection of the color change at the end point is remarkably affected by the difference of chemical composition of the sample, or of the aluminum content of the sample, or of the interfering elements co existed. Through a critical study of the factors concerned, it is found that the mole ratio of EDTA, copper and aluminum in the solution must be controlled to conform to the following range:EDTA∶Cu 2+ ∶Al 3+ =1∶(0.2~0.3)∶(0.7~0.8) and should follow the following relationship: n EDTA = n Cu+ n Al.更多还原