Adsorption And Separation Of Ga(?) From Sulfuric Acid System Using Solvent-impregnated Resins Containing Acidic Phosphorus Esters

Gallium and its compounds are widely used in the fields of electronics,metallurgy,medicine and aerospace due to their unique physical and chemical properties and excellent service performance,which leads to the increasing demand of gallium in recent years.However,independent gallium deposit is almost non-existent,and gallium exists mainly with trace components associated with other metal ore(such as bauxite,sphalerite,copper,iron ore,etc.)and some coal mines.When the gallium is extracted from these deposits,gallium content is low and it is difficult to separate from the cohesive metals.Therefore,it is urgently needed to find environmentally effective adsorption and separation technology to separate and extract gallium from the relevant deposits and resources.Solvent impregnation resins(SIRs)separation method combines excellent characteristics of solvent extraction method and ion exchange method organically,and the preparation method of SIRs is simple.It could be flexible to choose different carriers and extractants according to the actual situation,which is expected to achieve the separation and recovery of gallium.In this paper,P204 SIRs and P507 SIRs were prepared with styrene-divinyl benzene macroporous resin(HZ818)as the carriers,P204(bis(2-ethylhexyl)phosphate)and P507(2-ethylhexyl phosphonic acid 2-ethyl hexyl ester)as the extractant,respectively.In addition,coated SIRs(CSIRs)were prepared through coating P507 SIRs with polyvinyl alcohol(PVA).The adsorption and separation properties of Ga(?)in sulfuric acid system with these two kinds of impregnated resin were studied.In the static adsorption experiments,the optimum adsorption p H values of Ga(?)with P204 SIRs,P507 SIRs and P507 CSIRs were 1.8,3.3 and 3.3,and the corresponding adsorption capacities were 10.9 mg/g,13.7 mg/g and 12.1 mg/g,respectively.The adsorption equilibrium time was 20 h,14 h and 12 h(298 K),respectively.The kinetic adsorption processes were described by quasi-second-order kinetics and the isothermal adsorption were well consistent with the Langmuir isothermal adsorption model.The dynamic adsorption experiments showed that the low flow rate was favorable for the adsorption of Ga(?)with P507 SIRs.Ga(?)could be eluted easily with 1.5 mol/L HCl.The coating treatment could effectivelyimprove the stability of P507 SIRs impregnated resin.In Ga(?)-Zn(?),Ga(?)-Cu(?)binary mixtures,P507 SIRs had good adsorption selectivity for Ga(?),and Ga(?)could be separated and enriched by controlling the p H of the solution.While in Ga(?)-Fe(?)binary system and Ga(?)-Zn(?)-Cu(?)-Fe(?)complex system,P507 SIRs showed good adsorption selectivity for Fe(?),and little adsorption of Ga(?),which indicated that the presence of Fe(?)had a great effect on the adsorption of Ga(?).The adsorption and separation application of Ga(?)with P507 SIRs from fly ash of a power station was studied.The leaching amount of Ga(?)was 27.7 ug/g under the optimum leaching conditions,and 29.1% Ga(?)of primary recovery was abtained with SIRs colunmn adsorption and HCl solution elution under the optimum adsorption and separation conditions.