Water and solute activities of H2SO4-Fe2(SO4)3-H2O and HCl-FeCl3-H2O solution systems: Part i. activities of water

The activities of water of the H₂SO₄-Fe₂(SO₄)₃-H₂O solution system were determined by an isopiestic method and those of HCl-FeCl₃-H₂O by a transpiration method both at 298 K. The experimentally determined water activities satisfactorily obeyed the Zdanovskii rule. The activities of water in these solution systems were also calculated using the Robinson-Bower empirical equation. The water activities determined experimentally showed satisfactory agreement with the calculated values when the formation of Fe(III) complexes and the dissociation of acids were taken into consideration. This finding indicates that the empirical additivity rule proposed by Robinson and Bower is useful in estimating the water activities for these solution systems on the basis of composition data of mixed solutions.     

Water and solute activities of H2SO4-Fe2(SO4)3-H2O and HCl-FeCl3-H2O solution systems: Part II. Activities of solutes

The mean activity coefficients of solutes such as H₂SO₄ and Fe₂(SO₄)₃ in the solution system H₂SO₄-Fe₂(SO₄)₃-H₂O, and HCl and FeCl₃ in the solution system of HCl-FeCl₃-H₂O at 298 K were calculated by the McKay-Perring method using the water activities of these solution systems. The mean activity coefficients calculated by the McKay-Perring method were sufficiently accurate for use on concentrated mixed solutions. A Gibbs-Duhem equation, which is applicable for calculating mean activity coefficients of one component using the activity data of the other components, was also used to calculate the mean activity coefficient of Fe₂(SO₄)₃ in aqueous solutions of H₂SO₄-Fe₂(SO₄)₃ by using both the activity of water measured by an isopiestic method and that of H₂SO₄ determined by the McKay-Perring method. The Gibbs-Duhem method was more tedious for calculation than the McKay-Perring method, and it required thermodynamic data other than water activities.     

Water and solute activities in the aqueous H2SO4 -(NH4)2SO4 solutions

The activities of water in H₂SO₄-(NH₄)₂SO₄-H₂O solutions, the concentrations of which ranged from 0.1 to 4.0 mol kg_-1 H₂SO₄ and 0.1 to 5.0 mol kg_-1 (NH₄)₂SO₄, were determined by an isopiestic method at 298 K. The experimentally determined water activities showed considerable deviation from the Zdanovskii rule. The activities of water were not in agreement with those calculated from the Robinson-Bower equation, even though the formation of sulfato-complexes of NH₄(I) and the dissociation of sulfuric acid were taken into consideration. The behavior of H₂SO₄-(NH4)₂SO₄ solu-tions is quite different from other systems. Water activities of aqueous solutions of H₂SO₄-Li₂SO₄ and H₂SO₄-Na₂SO₄ can be calculated from the Robinson-Bower equation with satisfactory accuracy. The interesting behavior of (NH₄)₂SO₄ can be attributed to the water structure-breaking property of NH₄ ⁺ ions. An additivity equation for estimating the water activity of aqueous H₂SO₄ solutions con-taining (NH₄)₂SO₄ was proposed by considering the contributing effects of solutes on the structure of water. The proposed equation satisfactorily described the solution system under investigation. The mean activity coefficients of H₂SO₄ and (NH₄)₂SO₄ in the solution system, H₂SO₄-(NH₄)₂SO₄-H₂O, at 298 K, were calculated by the McKay-Perring method using the water activities experimentally determined. It is believed that the calculated values for concentrated solutions of more than one sol-ute are sufficiently accurate since the mean activity coefficients of H₂SO₄ agree with the values measured by the emf method.     

Water and solute activities of the solution systems of H2So4-Cuso4-H2O and Hci-Cuci2-H2O

The activities of water, α(H₂O), in the solution system of H₂SO₄-CuSO₄-H₂O were determined by an isopiestic method and those in the solution system of HCl-CuCl₂-H₂O by a transpiration method, both at 298 K. The activities of H₂SO₄ and H⁺ in the solution system of H₂SO₄-CuSO₄-H₂O were also determined at 298 K by the emf method. The water activities in both systems obeyed the Zdanovskii rule relatively well. The α(H₂O) experimentally determined in the sulfate system showed a satisfactory agreement with those calculated from the Robinson-Bower equation, assuming the complete dissociations of H₂SO₄ and CuSO₄, whereas a good agreement between the calculated and experimentally determined α(H₂O) for the chloride system was obtained when the formation of Cu(II) chloro-complexes was taken into consideration. The mean activity coefficients, γ_±, of solutes, including H₂SO₄, HC1, and CuCl₂ in these solution systems, were calculated at 298 K by the McKay-Perring method using the activity data. The γ_±(H₂SO₄) values in the solution system of H₂SO₄-CuSO₄-H₂O were in good agreement with those determined by the emf method. On the other hand, the γ_±(CuSO₄) were calculated at the same temperature based upon the Gibbs-Duhem equation using both measured α(H₂O) and calculated γ_±(H₂SO₄) values, because of solubility limitations.     

H_2O_2-Fe_2(SO_4)_3-H_2SO_4体系中辉铜矿的浸取研究

以H_2O_2和Fe_2(SO_4)_3为氧化剂、NaCl为助浸剂,在H_2SO_4溶液中浸出辉铜矿中的铜。结果表明,在反应温度85℃,反应时间180 min,H_2O_2、Fe_2(SO_4)_3、NaCl、H_2SO_4浓度分别为0.2、0.25、0.5、0.5mol/L的条件下,铜浸出率可达94.33%。采用XRD和EDS等手段对不同反应时间浸出残渣进行了表征与分析,初步揭示了辉铜矿浸取反应历程。     

Activities of water and solutes in the solution system H2SO4−Cr2(SO4)3−H2O

The activities of water in the solution systems of Cr₂(SO₄)₃−H₂O and H₂SO₄−Cr₂(SO₄)₃−H₂O were determined at 298 K by an isopiestic method. Properties of the green and violet isomers of Cr₂(SO₄)₃ were considered separately. The activities of water in aqueous solutions containing violet Cr₂(SO₄)₃ alone are considerably smaller than those of the green isomer. The water activities of aqueous H₂SO₄ solutions containing the violet isomer of Cr₂(SO₄)₃ satisfactorily obey the Zdanovskii rule, while those of the green isomer show an upward deviation from the Zdanovskii linearity. The activities of water in these solution systems were also calculated, using the Robinson-Bower empirical equation, and showed satisfactory agreement with the calculated values, whether the formation of the sulfato-complex, CrSO ₄ ⁺ , and the dissociation of H₂SO₄ were taken into consideration or not. The mean activity coefficients of H₂SO₄ and Cr₂(SO₄)₃, for the solution systems studied in this work, were calculated by applying the McKay-Perring method and its modified form, using the measured water activity data of these solution systems. The concentration dependencies of the mean activity coefficients of H₂SO₄ and Cr₂(SO₄)₃ in the solutions containing the green isomer are quite different from those of the violet isomer. Particularly, it was found that the activity values of water and solutes in the solution system of H₂SO₄-violet Cr₂(SO₄)₃−H₂O are similar to those of the solution system of H₂SO₄−Fe₂(SO₄)₃−H₂O. formerly Graduate Student with Kyoto University     

Resistance of titanium carbide powders synthesized by various methods,to the action of an H2O2 and H2SO4 solution

Translated from Poroshkovaya Metallurgiya, No. 3, pp. 102–105, March, 1992.     

Diffusion of H2-H2O through porous iron formed by the reduction of iron oxides

Measurements were made of the rate of equimolar counterdiffusion of hydrogen and water vapor through porous iron formed by the reduction of dense hematite, magnetite, and commercial iron ore pellets with hydrogen. The experiments were conducted at temperatures between 400° and 1000°C and at pressures between 0.1 and 40 atm. It is demonstrated that the structure of the porous iron is primarily a function of reduction temperature and that the diffusion process at the higher reduction temperatures is normal. The effect of gaseous diffusion on the rate of reduction of dense hematite with hydrogen is discussed. It is shown that gaseous diffusion limits the rate at the higher temperatures and pressures.     

Pt-Ir/C/PTFE疏水催化剂及催化H-D交换研究

制备了8种金属含量不同的Pt-Ir/C/PTFE疏水性催化剂，采用这些催化剂进行了H-D同位素气液对流、气汽并流交换实验，初步考察了温度、压力、氢气流速对催化活性的影响。实验表明，Ir的加入能够提高疏水催化剂的催化活性，当Ir在二元金属中的含量为25%时，催化剂的催化活性得到提高。     

[Nd(PW11O39)(H2O)3](H2bpy)2·4H2O的水热合成及晶体结构

采用水热法合成稀土无机有机杂化化合物[Nd(PW11O39)(H2O)3 ](H2bpy)2·4H2O.采用NdCl3·6H2O,(NH4)3PW12O40·3H2O, 4,4'-联吡啶(bpy),和去离子水(摩尔比为4∶1∶4∶3900, pH=6)在130℃下进行水热反应3天,得到标题化合物的紫红色块状晶体,并进行了红外光谱分析,元素分析.用单晶X射线衍射法测得晶体结构,属三斜晶系,空间群为P-1,晶胞参数为a=1.18824(9) nm,b =1.35707(10)nm,c=1.77691(13)nm,α=71.551(2)°,β=82.478(2)°,γ=80.568(2)°.该晶体由无机的共价链∞1[Nd(PW11O39)(H2O)3]4- 和有机的二质子化的4,4'-联吡啶(H2bpy)2 及结晶水分子堆积而成的, 是一个新的稀土磷钨酸盐无机有机杂化化合物.     

Effects of iron and temperature on solubility of light rare earth sulfates in multicomponent system of Fe2(SO4)3-H3PO4-H2SO4 synthetic solution

Numerous light rare earth elements (LREE) minerals containing Fe and P were processed by sulfuric acid roasting method, and the leaching solution mainly comprises LREE sulfate, Fe₂(SO₄)₃, H₃PO₄, and H₂SO₄, however, the solubility data of LREE sulfates in this system is few. This work studies the solubility of LREE sulfates in independent LREE sulfate system RE₂(SO₄)₃-Fe₂(SO₄)₃-H₃PO₄-H₂SO₄ (RE = La, Ce, Pr or Nd) and mixed LREE sulfates system (La,Ce,Pr,Nd)₂(SO₄)₃-Fe₂(SO₄)₃-H₃PO₄-H₂SO₄ at different temperature (25–65 °C) and concentrations of Fe₂(SO₄)₃ (Fe₂O₃, 0–50.13 g/L), H₂SO₄ (0.5 mol/L), and H₃PO₄ (P₂O₅, 20.34 g/L) based on the industrial operating condition at low liquid and solid ratio 2:1. The solubility of each LREE sulfate in the independent system (La₂O₃, 12.25–20.88 g/L; CeO₂, 41.93–62.35 g/L; Pr₆O₁₁, 37.34–56.69 g/L; Nd₂O₃, 26.60–37.63 g/L) is much higher than that of the mixed system (La₂O₃, 6.95–11.03 g/L; CeO₂, 10.63–21.51 g/L; Pr₆O₁₁, 11.56–20.36 g/L; Nd₂O₃, 12.36–19.79 g/L) under the same other conditions. The results also indicate that, in the two systems, both Fe and the temperature have negative effects on the solubility of LREE sulfates. That may occur due to the complication reactions between the complexes of RESO₄⁺ and Fe(SO₄)₂^–. However, the influence degree of temperature and iron concentration on the LREE sulfates solubility varies in the two systems and among different LREE species. This research is of theoretical significance for optimizing the conditions of the sulfuric acid process for recovering the LREE from the mixed LREE bearing minerals as well as the single LREE containing secondary rare earth scraps.     

Syntheses and Structures of Two Heteronuclear Complexes with Glycine {[CuEr(Gly)_5(H_2O)_2](ClO_4)_5·H_2O}_n and {[Cu_2Gd_2(Gly)_10 (H_2O)_4](ClO_4)_10·4H_2O}_n

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Cu(Ⅱ)-NH3-(NH4)2SO4-H2O体系浸出-电积生产铜的工艺研究

对氨法炼铜新工艺进行了探索性的研究,得到了NH3-(NH4)2SO4-H2O体系中浸出铜锌精矿焙砂及在氨性硫酸铜溶液中电积生成铜板的最佳工艺条件.在浸出时间2 h,氨水浓度3 mol/L,液固比6:1,温度40℃的条件下,铜的浸出率为65.39%;电积最佳条件为铜离子浓度30 g/L,电解液温度40℃,电流密度200A/m2,电流效率达到85.66%.     

In2S3-H2O系电位-pH图

通过热力学计算,给出了In2S3-H2O系的反应平衡式及电位-pH的关系式,并绘制了25 ℃和150 ℃下In2S3-H2O系的电位-pH图,为含硫化铟的矿物高温氧化浸出提供了一定的热力学数据.