A modified Hull cell and its application to the electrodeposition of zinc

An analytical electrochemical cell based on the Hull cell is described. The cell was tailored specifically for the analysis of electrowinning or elect roplating. Current density distributions were generated by asymmetric inser tion of an insulating baffle between parallel electrodes. The position and length of the baffle were easily altered, giving 12 possible distributions for a single total current. The cathode consisted of 10 electrically isolat ed 1 cm(2), aluminium segments. By logging the potential drop across 1 Omeg a resistors in each of the 10 isolated parallel branches, quantitative dete rmination of current densities across the cathode was made possible. The sm all segments facilitated microscopic analysis of deposit morphologies. A te chnique for the determination of current efficiencies on each segment is de scribed and demonstrated. The technique obviates the necessity to determine deposited masses directly. Development of the technique for industrial app lication is detailed. The system is demonstrated by evaluating known effect s of variables in zinc electrowinning. The variables examined were temperat ure, deposition time, acid concentration and antimony contamination.