Extraction of Fe from sulfuric acid leaching solution of high-aluminum fly ash by P204

This paper researched the separation performance of Fe(Ⅲ) and Al(Ⅲ) from a high-aluminum CFA (coal fly ash) sulfuric acid leaching solution. When such a leaching solution (C(Al³⁺)=37.1 g/L, C(Fe³⁺)=5.1 g/L) was simulated, Fe(Ⅲ) and Al(Ⅲ) in the composition solution were extracted by using a P204+260^# solvent oil extraction system. The effects of different parameters, such as the volume fraction of P204, temperature, reaction time, pH of the initial aqueous phase and organic-to-aqueous phase ratio V_(O): V_(A), on the extraction of Fe(Ⅲ) with P204 were investigated. Experimental results showed that when the CFA acid leaching solution was 40% P204 and 60% 260^# kerosene at pH of 0.4 at 60 ℃ and the phase ratio of V_(O): V_(A)=1:1 contacted for 20 min, Fe(Ⅲ) extraction was 93.24% with 2.3% Al(Ⅲ) coextracted. The Fe-loaded organic phase was stripped with 5 mol/L HCl at an organic-to-aqueous phase ratio of 1:3, and almost 92.96% of the Fe(Ⅲ) was recovered from the Fe-loaded organic phase contact for 10 min.