Abstract: Solid sulfur pellets are made by dropping sulfur particles in two distinct curtains of particles within a drum having a tumbling bed of such particles. The larger curtain of particles is sprayed with molten sulfur and the smaller is sprayed with water above the bed. This indirect application of water keeps the temperature of the bed as well as the other curtain of particles being sprayed with sulfur within predetermined temperature ranges which produce high quality sulfur pellets. Dust emissions are prevented by classifying as to size a third falling curtain of recycled particles and spraying molten sulfur on the side containing dust particles. Seed nuclei are produced by intermittantly raising the temperature of the tumbling particle bed about 40.degree. F. for short periods of time.

Abstract: Molten sulphur is cooled to as low as 5.degree. F above its solidification temperature without being in direct contact with the heat exchange liquid. Such liquid is recirculated and is initially cooled to a first temperature below the solidification temperature of the molten sulphur and then heated to a predetermined second temperature which is also below such solidification temperature.