拜耳循环母液镓吸附—萃取富集试验

Enrichment of Gallium From Bayer Circulating Mother Liquor by Adsorption and Liquid-liquid Extraction

针对拜耳循环母液回收镓过程中溶液钒、铝、硅等杂质影响后续电解高纯金属镓的纯度和电解效率等问题,采用螯合树脂吸附-酸解吸-磷酸三丁酯(TBP)萃取—反萃取工艺除杂富集镓的试验。结果表明:(1)偕胺肟螯合树脂对氧化铝循环母液中的镓具有良好的选择吸附性能,当吸附时间为60 min、吸附温度为35℃、吸附树脂质量4 g时,镓的吸附率达82%;酸对含镓树脂具有良好的解吸效果,1.5 mol/L的盐酸在室温10 min对镓的解吸率达72%,硅和钒基本不解吸;(2)萃取结果表明,体积分数为20%的TBP(煤油为稀释剂)在3 mol/L的盐酸体系下对解吸下来的镓进行萃取,镓的萃取可达到99%以上,铝萃取率基本为零;采用1~4 mol/L的氢氧化钠,反萃取率可达到85%~97.41%,氢氧化钠中镓浓度达5000~6400 mg/L,不含铝、硅、钒,实现镓的富集提纯。采用树脂吸附和萃取联合工艺,可获得高浓度含镓溶液,与现有工艺相比提高10倍,且不含钒、铝、硅等杂质,获取等质量Ga(OH)3时明显减少酸碱用量,降低药剂成本。

There are many kinds of impurities(vanadium,aluminum,silicon,etc.)in Bayer circulating mother liquor which would affect gallium purity and electrolysis efficiency.Therefore,this paper proposed a method of enrichment of gallium from Bayer circulating mother liquor by adsorption and liquid-liquid extraction(TBP)and provide high quality electrolytic raw materials for electrolytic gallium.The results showed that amidoxime chelating resin had a good selective adsorption for gallium.When adsorption time was 60 min,adsorption temperature was 35℃and adsorption resin dosage was 4 g,the adsorption rate of gallium reached 82%.Acid had a good effect for desorbing Ga from resin.Desorption rate of Ga reached 75%with 1.5 mol/L HCl at room temperature in 10 min,and the Si and V were basically not desorbed.The extraction results showed that the gallium was extracted by volume fraction of 20%TBP(kerosene as diluent)in 3 mol/L HCl system.The extraction of gallium could reach 99%,and the aluminum extraction rate was basically zero.And then Ga was back-extracted,and back-extraction rate reached 96.63%with 1~4 mol/L NaOH at room temperature.The concentration of Ga in sodium hydroxide reached 5000 to 6400 mg/L without Al,Si and V.Achievement of the enrichment and purification of gallium was obtained.High concentration gallium solution can be obtained by combining process of resin adsorption and extraction.Concentration of Ga was 10 times higher than the existing process,and the solution did not contain vanadium,aluminum and silicon.When obtaining the same mass of Ga(OH)3,the acid and alkali dosage can be significantly reduced,and so do the agents cost.