【摘要】 在323～363 K的温度范围内，测定了Zn O,Cu₂O,Cu O等一系列含锌烟尘中常见金属氧化物在氯化胆碱-尿素（Ch Cl-urea）低共熔溶剂中的溶解度，发现Zn O和Cu₂O溶解度较大，分别介于0.1906%～37.2683%和0.0220%～3.1470%之间，远高于Cu O,Ni₂O₃,Co₂O₃和Fe₃O₄的溶解度（0.0045%～0.1803%,0.0070%～0.2574%,0.0034%～0.1174%和0.0007%～0.0045%）。当温度从323 K升高到363 K,Zn O和Cu₂O在Ch Cl-urea中的溶解度迅速增加，分别达到195和146倍，而Cu O,Ni₂O₃,Co₂O₃和Fe₃O₄的溶解度仅分别增加了40,36,34和66倍。通过回归分析，得到了溶解度随温度变化的经验方程。建立了Ch Cl-urea溶剂与固体金属氧化物的两相平衡，并通过相平衡规律，分别计算了不同金属氧化物在Ch Cl-urea低温熔盐中的活度系数、过剩溶解吉布斯自由能、过剩焓以及过剩熵。随着温度的升高，各个金属氧化物在Ch Cl-urea中的活度系数逐渐减小。此外，在Ch Cl-urea低共熔溶剂中Zn O活度系数远小于其他金属氧化物活度系数，表明低共熔溶剂对Zn O的吸引力大于对其他金属氧化物的吸引力。同时，ZnO溶解在ChCl-urea低共熔溶剂的过剩熵也较小，约为79 J?mol^-1，表明溶解有ZnO的低共熔溶剂溶液体系更接近于规则溶液。更多还原

【Abstract】 Deep eutectic solvents （DESs）,which are prepared from quaternary ammonium salts mixed with hydrogen bond donors（HBD） such as amides,alcohols and carboxylic acids,have been developed as a promising solvent for organic synthesis,extraction and separation of metal and metal electrodeposition due to their excellent physicochemical properties.Additionally,they can selectively dissolve valuable metal oxide such as zinc oxide and cuprous oxide,but are unable to dissolve gangue ingredients including ferric oxide,calcium oxide and aluminium oxide,which offers an effective way for the recovery of zinc from zinc-containing secondary resources such as steelmaking dust,zinc slag,zinc smelting fume,etc.But so far,there are very few studies on the dissolution of metal oxides in deep eutectic solvents,and the relevant data are very scarce.Thus,it is of great interest to measure the solubility of metal oxides in deep eutectic solvents systematically and to study their thermodynamics of dissolution.Here,the solubility of main metal oxides that present in steel-making dust,including Zn O,Cu₂O,Cu O,Ni₂O₃,Co₂O₃ and Fe₃O₄,in Ch Cl-urea DES was systematically measured by chemical method in the temperature range of 323～363 K.It was found that the solubility of these metal oxides in Ch Cl-urea DES varied widely.The solubilities of Zn O and Cu₂O in Ch Cl-urea ranged from 0.1906%to 37.2683%and from 0.0220%to 3.1470%respectively,which were much higher than those of Cu O （0.0045%～0.1803%）,Ni₂O₃ （0.0070%～0.2574%）,Co₂O₃ （0.0034%～0.1174%） and Fe₃O₄（0.007%～0.0465%） in Ch Cl-urea DES.This demonstrated that Zn O and Cu₂O had good solubility in Ch Cl-urea DES,while the rest of metal oxides were slightly soluble or insoluble in Ch Cl-urea DES,which was conducive to the selective dissolution of zinc from steelmaking dust.With an increase of temperature from 323 to 363 K,the solubility of all metal oxides in Ch Cl-urea DES increased rapidly,but the degree of increase was different.The solubilities of Zn O and Cu₂O increased by about 196 times and 143 times,while the solubilities of Cu O,Ni₂O₃ and Co₂O₃ only increased by 40,36,34 and 66 times.The solubility of each metal oxide in Ch Cl-urea DES was correlated with temperature,and it was found that the relationship between the solubility of Zn O and temperature was parabolic,and the solubilities of other oxides were linear with temperature.By fitting them,the empirical equations of solubility for these metal oxides were regressed.The phase equilibrium relationships between metallic oxide and Ch Cl-urea DES were established,and the activity coefficient,excess Gibbs free energy,excess enthalpy and excess entropy of different metal oxide in Ch Cl-urea DES were respectively calculated according to the rules of solubility equilibrium.The activity coefficients of all metal oxides in Ch Cl-urea were greater than 1 except for that of Zn O at higher temperature（≥343 K）,indicating that Ch Cl-urea solution of metal oxides largely had a positive deviation from the ideal solution.At the same temperature,the activity coefficient of Zn O in Ch Cl-urea DES was much smaller than that of other metallic oxide in Ch Cl-urea DES,indicating that interaction between Zn O and Ch Cl-urea was much stronger than those of other metal oxides with Ch Clurea DES.For the same metal oxide,the activity coefficient decreased with the increase of temperature,which was because the solubility of metal oxides increased with the increase of temperature,and the interaction of metal oxides and low eutectic solvents was enhanced.Based on the relationship between excess Gibbs free energy and activity coefficient,excess Gibbs free energy of various metal oxides in Ch Cl-urea DES at different temperatures could be obtained by calculating.The excess Gibbs free energy of zinc oxide in Ch Cl-urea DES was far smaller than that of other metal oxides.Moreover,excess Gibbs free energy of each metal oxide decreased with the increase of temperature,and the relationship between them was linear.Through linear fitting of the relationship between excess Gibbs free energy and temperature,the excess entropy and excess enthalpy of metal oxides in Ch Cl-urea DES were obtained.It was found that the excess enthalpy of metal oxide in Ch Cl-urea DES was larger compared to that in aqueous solution and high temperature molten salt,which might be due to the different structure and properties of Ch Cl-urea DES and aqueous solutions （or high temperature molten salt）.In addition,the excess enthalpy and excess Gibbs free energy of Zn O in Ch Cl-urea were also lower than those of other metal oxides,which was ascribed to the smaller activity coefficient of Zn O in Ch Cl-urea.This result indicated that the property and behavior of the solution obtained by Zn O dissolving in Ch Cl-urea were closer to the ideal solution compared to those of the solution formed by other metal oxide dissolving in Ch Clurea.Meanwhile,excess entropy of Zn O in Ch Cl-urea was 79 J?mol^-1 and was relative lower,suggesting that the behavior of Ch Cl-urea solution containing ZnO was close to regular solution.更多还原