亜鉛電解液の密度および粘性に及ぼす共存硫酸塩の影響
1988 年 104 巻 1209 号 p. 829-836
詳細
1988 年 104 巻 1209 号 p. 829-836
Density and viscosity coefficient were measured for acidic zinc sulphate solutions containing one of the sulphates of magnesium, manganese, sodium and potassium over a temperature range between 20 and 60°. These four sulphates were taken as typical impurity sulphates affecting the physical properties of the electrolyte solutions in electrowinning of zinc. Concentrations of the sulphates considered here are as follows: H2SO4, 100-200 g/l; Zn, 0-80 g/l; Mg, 0-20 g/l; Mn, 0-15 g/l; Na, 0-14 g/l; K. 0-24g/l.
Equations were derived to describe the variation of the density and viscosity coefficient with the solution composition andtemperature. The following expression fits all the data of solution density with very small standard deviation of 0.0008 g/cm3.
ρ(g/cm)=1.0112-4.4+0.8[H2SO4]+1.3[M]10-4t+0.061[H2SO4]-0.0049[M]
[M]mol/l=[Zn]+0.68[Mg]+0.83[Mn]+0.32[Na]+0.37[K]
where [M] is a modified concentration of the sulphates, which is calculated from the analytical value (mol/l) for each metal ion in the solution at 20°and t is temperature in °.
Variation of the viscosity coefficient with solution composition was expressed by a quadratic functionof the acid concentration and a modified concentration of the metal sulphates at each temperature. A very close similarity was observed in the effect of the concentration of the sulphates of the divalent metals, ZnSO4, MgSO4 and MnSO4, on the viscoscositycoefficient.
The temperature dependence of viscosity coefficient of a series of the acidic zinc sulphate solutions containing magnesium sulphate was described with high precision by Andrade's equation, ρ=ρ0exp (Ev/RT)
whereρ(cP) and Ev (J/mol) were given as follows:ρ(cP) =1.77×10-3+4.1×10-4[H2SO4]-(1.0×10-4+2.5×10-4[H2SO4])([Zn]+[Mg]) (Ev(J/mol)=15200+(1850+225[H2SO4])[Zn]+[Mg])
