Research is reported on the development of a process to electrochemically oxidise sulphur dioxide gas, absorbed into sulphuric acid solutions. This process is aimed at the recovery of potentially valuable sulphur species, from waste and effluent gases, as sulphuric acid. A small pilot scale sieve-plate electrochemical reactor (SPER) is used for the oxidation of SO2. The SPER is an undivided cell using, in this case, monopolar connected electrodes. The anode material was platinised titanium or lead dioxide and the cathode material was zirconium metal or Ebonex(R), both materials do not form sulphur in the electrolysis of SO2 in solutions of sulphuric acid. Typical current efficiencies are above 80% at current densities of 10-20 mA cm(-2). Energy consumptions are between 1.8 and 2.4 kWh kg(-1). Production of sulphuric acid at concentrations of 6 mol dm(-3) by anodic oxidation of SO2 is demonstrated. The mass-transfer behaviour of the sieve-plate reactor is particularly good for this reaction involving relatively low concentrations of dissolved SO2 concentration. The behaviour of the sieve-plate reactor is mathematically modelled.