(廣州有色金屬研究院 廣東省稀土開(kāi)發(fā)及應(yīng)用重點(diǎn)實(shí)驗(yàn)室，廣州 510650)
摘 要: 對(duì)N235萃取除鐵進(jìn)行研究，考察H2O2用量、料液初始pH、萃取劑濃度、萃取劑組成、萃取時(shí)間對(duì)萃取的影響以及H2SO4濃度、反萃時(shí)間對(duì)反萃的影響，設(shè)計(jì)錯(cuò)流萃取過(guò)程并繪制反萃平衡等溫線，對(duì)萃取劑轉(zhuǎn)型條件進(jìn)行研究。結(jié)果表明：H2O2用量為理論量3.85倍時(shí)可將Fe2+完全氧化成Fe3+，并采用有機(jī)相組成30%(體積分?jǐn)?shù))N235+10%(體積分?jǐn)?shù))TBP+磺化煤油作為萃取劑，料液初始pH為0.11，其最佳萃取條件如下：萃取溫度25 ℃，萃取時(shí)間2 min，相比O/A為1:1。經(jīng)過(guò)4級(jí)錯(cuò)流萃取，其Fe3+萃取率可達(dá)96.96%，Cu2+、Co2+、Ni2+損失率分別為3.04%、1.39%和3.84%，有機(jī)相負(fù)載采用0.3 mol/L硫酸可反萃得到純度為98.87%的Fe2(SO4)3溶液，其最佳反萃條件為反萃溫度25 ℃，反萃時(shí)間6 min，相比O/A=1:1。經(jīng)兩級(jí)逆流反萃，F(xiàn)e3+反萃率達(dá)99.12%，反萃鐵后的負(fù)載酸有機(jī)相經(jīng)Na2CO3中和轉(zhuǎn)型，返回使用。
關(guān)鍵字: N235；硫酸浸出液；萃取；除鐵；反萃；轉(zhuǎn)型
（Guangdong Province Key Laboratory of Rare Earth Development and Application,
Guangzhou Research Institute of Non-ferrous Metals, Guangzhou 510650, China）
Abstract:The extraction of Fe3+ by N235 was studied based on the technology gap on the removal of Fe3+ from iron rich and high acidity sulfuric acid leaching liquid by extraction. The effects of H2O2 dosage, feed initial pH, extractant concentration, extractant composition and extraction time on the extraction, and the effects of H2SO4 concentration and tripping time on the stripping were investigated. The cross current extraction process was designed and the isotherms of stripping were plotted, and the conditions of extractant transformation were researched. The results show that, when 30% (mass fraction) H2O2 dosage is 3.85 times of theoretical one, Fe2+ can be oxidized into Fe3+ totally, and with 30% (volume fraction) N235 and10% (volume fraction) TBP in sulphonated kerosene as extractant, the extraction rate of Fe3+ from the solution with initial pH of 0.11 reaches 96.67% in four-stage cross current extraction with O/A ratio of 1:1 (volume ratio of oil phase to aqueous phase) at 25℃ for 2 min, and the loss rate of Cu2+, Co2+, Ni2+ are 3.04%, 1.39%, 3.84%, respectively. The Fe3+ in loaded organic can be stripped into Fe2(SO4)3 with purity of 98.87% using 0.3 mol/L H2SO4 solution and the stripping rate reaches 99.12% in two-stage counter current stripping with O/A ratio of 1:1 (volume ratio of oil phase to aqueous phase) at 25 ℃ for 6 min. After stripping, the acid in loaded organic phase can be neutralized using Na2CO3. The organic phase returns to extraction circularly.
Key words: N235; sulfuric acid leaching liquid; extraction; iron removal; stripping; transformation
