GB478230A - Process and apparatus for the purification of sulphur - Google Patents

Abstract

<PICT:0478230/III/1> <PICT:0478230/III/2> Sulphur is purified by subjecting it in the molten state to a high voltage unidirectional electrical field whereby suspended impurities collect near the surface of one electrode and the part of the sulphur containing the impurities is removed. The sulphur is preferably passed through a tank 1 having the cross-section shown in Fig. 2 and maintained at a suitable temperature, preferably that giving minimum viscosity of the sulphur e.g. about 150 DEG C., by steam coils 7. A plate 11 forms the collecting electrode and the other electrodes consist of a series of wires 5 arranged on frames 4 and suspended from insulators 6. The tank is preferably divided by a plate 12 having an opening 13, and the upper frames 4 of the electrode are preferably level with the surfaces of the bath. The impurities collected on electrode 11 fall into the trough at the bottom of the tank and are periodically removed through ports 14, which are heated to maintain the sulphur liquid. The impure sulphur is fed in through opening 8, being deflected below the level of the molten sulphur by baffle 16, and pure sulphur leaves by pipe 9. For example, the electrodes may be spaced 6 inches apart and a voltage drop of 60,000 volts maintained between them.