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

Química Nova

Wenhui Shi¹  Lin Yang¹  Quanjun Fu¹  Zhiye Zhang¹  Xinlong Wang¹ 

[1] ,Sichuan University School of Chemical Engineering Chengdu,China

关键词: reverse flow injection;    sulfate;    turbidimetry;   

DOI  :  10.5935/0100-4042.20140196

来源: SciELO

【 摘 要 】

An improved method based on reverse flow injection is proposed for determining sulfate concentration in the wet-process of phosphoric acid (WPA). The effect of reagent composition, flow rate, temperature, acid concentration, length of the reaction coil, and linear response range on the flow system is discussed in detail. Optimal conditions are established for determining sulfate in the WPA samples. Baseline drift is avoided by a periodic washing step with EDTA in an alkaline medium. A linear response is observed within a range of 20 - 360 mg L-1, given by the 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 less than 1.60%. This method has a rate of up to 29 samples per hour, and the results compare well with those obtained with gravimetric method.

【 授权许可】

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