Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

• Published in: Chinese journal of chemical engineering Vol. 27; no. 5; pp. 1050 - 1057
• Main Authors: Leng, Xinke, Zhong, Yanjun, Xu, Dehua, Wang, Xinlong, Yang, Lin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2019; School of Chemical Engineering, Sichuan University, Chengdu 610065, China
• Subjects: Cation exchange resin; Diffusion models; Kinetics models; Purification of wet-process phosphoric acid; Diffusion models; Kinetics models; Purification of wet-process phosphoric acid; Cation exchange resin
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2018.09.012

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g−1 and 5.18 mmol·g−1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with SO3H in resin. The removal process was studied as a function of temperature, H3PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g−1 resin when the operating parameters were T = 50 °C, H3PO4 content = 27.61 wt% and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol−1. The overall reaction process was mainly controlled by pore diffusion.