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近年来,应用非离子表面活性剂作为胶束增溶分光光度法测定铝的报道较多,而用于络合滴定铝也有报道,过去多用二甲酚橙或PAN直接滴定或返滴定,文献介绍PAN金属络合物难溶于水,而在非离子表面活性剂存在下则易溶于水。本文基于以非离子表面活性剂吐温-80为增溶剂,PAN为指示剂,研究了络合滴定铝的条件,试验证明,在室温下pH4—5的乙酸介质中,加入过量EDTA,煮沸,冷却,用铜盐返滴定,终点非常敏锐,pH范围扩大,与经典的络合滴定法对比,结果很满意,完全适用于铝土矿、粘土、水泥等试样中铝的测定。
In recent years, the application of nonionic surfactant as micellar solubilizing spectrophotometry for the determination of aluminum has been reported, and for the complexation titration of aluminum has also been reported in the past with xylenol orange or PAN direct titration or back titration, literature introduction PAN metal complexes are poorly soluble in water and readily soluble in water in the presence of nonionic surfactants. Based on the non-ionic surfactant Tween-80 as a solubilizer and PAN as an indicator, the conditions of complexation titration of aluminum were studied. The results showed that EDTA was boiled at pH4-5 in acetic acid at room temperature, Cooled, back titration with copper salt, the end point is very sharp, the pH range expanded, compared with the classic complexometric titration, the results are very satisfactory, fully suitable for the determination of aluminum in bauxite, clay, cement and other samples.