电渗析法研究硝酸中铌胶体

A STUDY OF THE BEHAVIOUR OF NIOBIUM COLLOID IN NITRIC ACID SOLUTION BY ELECTRODIALYSIS

在0.5mol/l HNO_3中,铌量于示踪量到2×10^(-4)mol/l的范围内,进行了18种铌浓度的电渗析实验。铌的表观渗析率与浓度关系曲线中出现两个“坪”,反映了铌胶体形成情况。实验结果表明,0.5mol/l HNO_3中。就电荷而言,可渗析和不可渗析的铌均以带正电荷和中性两种状态存在。

In this paper the formation of niobium colloid in 0.5mol/l HNO3 of various concentrations of niobium by electrodialysis is studied. Using five cells separated by four semipermeable membranes, the electrode action on the medium in the mid-cell is weakened, and the concentration of nitric acid in the mid-cell is almost constant during the test process. It is observed that the form of niobium colloid formed varies with the 'apparent dialysis ratio' . The electric character of colloid particle is given.The behaviour of electrodialysis of niobium with the concentration of 1×10-6 mol/l is the same as trace niobium. In this case, no niobium colloid is formed in the solution. If niobium concentration is in the range of 7 to 9×10-6mol/l, the 'apparent dialysis ratio decreases significantly, which shows that niobium colloid is being formed partly. If the concentration of niobium is higher than 1×10-6mol/l in the solution, 'apparent dialysis ratio' decreases sharply and appears in the curve with two 'plateaus' .The 'plateaus' show that the colloid particles of niobium are in different sizes.