Determination of sulfate in the wet-process of phosphoric acid by reverse flow injection

Quimica nova

Wang, Xinlong¹  Fu, Quanjun¹  Yang, Lin¹  Zhang, Zhiye¹  Shi, Wenhui¹ 

[1] Sichuan University, Chengdu, China

关键词: reverse flow injection;    sulfate;    turbidimetry.;   

DOI  :  10.5935/0100-4042.20140196

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

An improved methodbased on reverse flow injection is proposed for determining sulfate concentrationin the wet-process of phosphoric acid (WPA). The effect of reagent composition,flow rate, temperature, acid concentration, length of the reaction coil, andlinear response range on the flow system is discussed in detail. Optimal conditionsare established for determining sulfate in the WPA samples. Baseline drift isavoided by a periodic washing step with EDTA in an alkaline medium. A linearresponse is observed within a range of 20 - 360 mg L-1, given bythe equation A = 0.0020C (mg L-1) + 0.0300, R2 = 0.9991.The detection limit of the proposed method for sulfate analysis is 3 mg L-1,and the relative standard deviation (n = 12) of sulfate absorbance peak is lessthan 1.60%. This method has a rate of up to 29 samples per hour, and the resultscompare well with those obtained with gravimetric method.

【 授权许可】

CC BY