Electrochemical refining of tin through thin-layers of molten electrolytes

A new principle of tin refining in molten electrolytes is proposed. Its main feature is mass transfer between electrodes through a thin porous diaphragm of (0.5-1.0)mult10 exp -3 m thickness, which is impregnated with molten electrolyte. The distance between the electrodes is equal to the diaphragm thickness. A mixture of zinc chlorides, alkali chlorides and tin chlorides is proposed as an electrolyte. It is shown that thin layer electrolysis makes it possible to produce tin with an impurity content no more than 1mult10 exp -3 %. The thin layer electrolysis in melts reduces the specific electrical energy by a factor of 1.5-2.0 and the electrolyte consumption by a factor of 2.5-6.0/ton of purified tin in comparison with current practice. The results show the proposed method of thin layer electrolysis in molten electrolytes to be promising for tin refining.