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用铁氰化钾滴定铁面矿石中亚铁有许多好处:铁氰化钾能得到很高的纯度,本身可作为基准物质,共水溶液非常稳定;在EDTA存在下,许多非还原性金属离子对滴定不干扰;可以在Fe(Ⅲ)与Fe(Ⅱ)共存时单独滴定Fe(Ⅱ)。铁氰化钾滴定亚铁一般用指示剂法或电位法确定滴定终点,也有采用方波技术,用i～E曲线的斜率确定终点的。但Fe(Ⅲ)对指示剂有封闭作用,仪器方法则需要作图,所以该方法虽好,由于指示终点的办法不理想,从而限制了它的应用。
Potassium ferricyanide titration of ferrous iron ore has many advantages: ferricyanide can be very high purity, itself can be used as a reference substance, the total aqueous solution is very stable; in the presence of EDTA, many non-reducing metal ion pairs Titration does not interfere; can Fe (Ⅲ) and Fe (Ⅱ) when the separate titration of Fe (Ⅱ). Potassium ferricyanide titration Ferrous commonly used indicator method or potentiometric method to determine the titration end point, but also the use of square wave technology, with the slope of the i ~ E curve to determine the end point. However, Fe (III) has a blocking effect on the indicator, and the instrumental method needs to be plotted. Therefore, although this method is good, the method of indicating the end point is not ideal, which limits its application.