Abstract: 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℃, 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.

Key words: Purification of wet-process phosphoric acid, Cation exchange resin, Kinetics models, Diffusion models

摘要： 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℃, 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.

关键词: Purification of wet-process phosphoric acid, Cation exchange resin, Kinetics models, Diffusion models