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用胺类非水体系测定钢铁中的碳,近年来已有报导和应用,其中乙醇—乙醇胺非水容量法已由冶金部定为部颁标准分析方法。该法具有无毒,快速、吸收率高及测定范围广等优点,但仍存在滴定终点不够明显、管壁润湿吸附等现象,引起分析测定的误差。本文就该法存在的问题作了相应的改进,进一步提高了分析结果的准确度。 一、指示剂的选择 本文对碱性范围的多种指示剂进行了筛选,观察它们在乙醇—乙醇胺非水体系内滴定终点变色情况。由于乙醇胺的缓冲作用,滴定曲线显得平坦,仅在pH9～12之间出现较小的
Determination of carbon in steel with amines non-aqueous system has been reported and applied in recent years, of which the ethanol-ethanol amine non-water volume method has been set by the Ministry of Metallurgical as a ministerial standard analytical method. The method has the advantages of non-toxic, rapid, high absorption rate and wide range of measurement, but there are still some problems such as the end point of the titration is not obvious enough and the wall wetting adsorption phenomenon causes the analysis and determination error. This article made a corresponding improvement on the problems existing in the law, and further improved the accuracy of the analysis results. First, the choice of indicator In this paper, a variety of indicators of the alkaline range were screened to observe their non-aqueous ethanol-ethanol amine titration endpoint discoloration. Due to the buffering effect of ethanolamine, the titration curve appears flat, with only minor differences between pH 9 and 12