Application of EDTA titration combined with acid base titration in simultaneous determination of zinc and tin in alkaline solution as well as determination of free alkali
SUN Bin-bin, TONG Jun, LU Hui, JIANG Jia-chao*
School of Environment Science and Spatial Informatics, China University of Mining ＆ Technology,Xuzhou 221116, China
Abstract：At present, the determination of zinc content in alkaline solution by EDTA titration method has been used in alkaline zinc smelting industry, while the content of tin in alkaline solution is usually determined by iodometry. However, there are few reports on the simultaneous determination of zinc and tin in alkaline solution by EDTA titration method. The simultaneous determination of zinc and tin in alkaline solution by EDTA titration was proposed. Meanwhile, the content of free alkali in alkaline solution was determined by acid base titration. In EDTA titration process, EDTA was used as chelating agent for the complexation of zinc and tin in alkaline solution. The pH of solution was adjusted to 5-6 using hexamethylenetetramine as the buffer solution. Ammonium fluoride was selected as the releasing agent for the demasking and releasing of tin. Then the content of tin was obtained by back titration with lead nitrate. The content of zinc in alkaline solution could be calculated according to the difference value of lead nitrate. The double indicator method was employed in acid base titration. The content of free alkali (expressed in sodium hydroxide) could be calculated using the content of tin and the amount of consumed hydrochloric acid. The contents of zinc, tin and sodium hydroxide in alkaline solution were determined according to the experimental method. The relative standard deviations (RSD, n=5) of measured results were less than 2%. The recoveries were between 94% and 99%.
孙彬彬, 童俊, 鹿慧, 蒋家超. EDTA滴定法结合酸碱滴定法用于碱液中锌、锡的联合测定以及游离碱的测定[J]. 冶金分析, 2018, 38(5): 54-59.
SUN Bin-bin, TONG Jun, LU Hui, JIANG Jia-chao. Application of EDTA titration combined with acid base titration in simultaneous determination of zinc and tin in alkaline solution as well as determination of free alkali. , 2018, 38(5): 54-59.
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