GB391514A - Improvements in and relating to the production of zinc white - Google Patents

Abstract

In the continuous production of zinc white, metallic zinc is vaporized in a rotary chamber in the presence of sufficient carbonaceous material to provide a local reducing condition about the zinc and to prevent the formation of any free pool or bath by the distribution <PICT:0391514/III/1> of the molten zinc about the carbonaceous material. The carbonaceous material used may be partly replaced by lump material such as firebrick. Vaporization is effected wholly or mainly by heat derived from the partial combustion of the vapours above the charge, which are then carried by the air current into an adjoining combustion zone where complete combustion is effected preferably by the admission of secondary air, the vapours being subjected to a symmetrical gradation of temperature. The process may be carried out in a rotary cylinder comprising a vaporizing zone b and a combustion zone c, Fig. 2, or two separate juxtaposed cylinders may be used. The zone b is initially heated by a burner g and the zinc and carbonaceous material are charged by a shoot e, comprising a nest of water-cooled pipes. Secondary air is admitted to zone c by adjustable valves i. As shown in Fig. 1, the oxide vapours pass up a water-cooled tower B provided with an internal water-spray, and thence through cyclone separators C, D to a baghouse F. A fan E serves to induce an air current through the whole apparatus, the effective suction at the outlet of the combustion zone being varied if desired by providing an adjustable opening at the foot of the tower B.