重铬酸钠生产中酸化率控制对指示剂选择的探讨

Discussion on choice of indicators of acidification rate control in sodium dichromate production process

工业重铬酸钠生产过程中,酸化率的控制是生产优质重铬酸钠成品的保证。在酸化率检测过程中选择一种高效、灵敏的指示剂是稳定控制酸化率的保证。研究结果表明,选用石蕊指示剂测定酸化率,可避免橙红色的重铬酸钠对滴定终点的干扰,其滴定终点比选用酚酞或者二甲基黄指示剂明显,还可以减少人为操作误差,对酸化率的控制有着积极的意义。

Acidification rate is the critical control point in producing high-quality sodium dichromate.At present,the acidifi- cation rate is mainly controlled by acid-base titration in the industrial production of sodium dichromate process.Therefore, in order to guarantee the stable control of acidification rate, an efficient and sensitive acid-base indicator should be selected.This research chose dimethyl yellow,litmus, and phenolphthalein indicators to make contrast verification test in terms of sensitivity of end point titration, color interference, and titration error rate.Resuhs showed litmus indicator could avoid the interference of by orange red sodium dichromate to the titration end point and had a more apparent end point of titration than those of other two indicators.Furthermore, it could also reduce human errors and had a positive meaning on the acidification rate control.