GB295975A - Improved method and apparatus for the production of red lead - Google Patents

Abstract

295,975. Hayward, E. Feb. 22, 1927. Red lead.-The production of red lead by reacting lead or a lead compound such as the carbonate or monoxide under heat and pressure with air or oxygen is carried out in a continuous manner without loss of pressure in the reaction chamber. Pressures of the order of 20-30 atmospheres and temperatures up to 450-500 ‹C. may be employed. As shown in Fig. 1, the pulverulent or granular initial material is fed from a hopper 21 through a valve 22 into an intermediate chamber from which a conveyer 23 passes it through a second valve 25 into the reaction chamber 4 which is surrounded by a casing 7 which may contain molten lead and by a casing 8 containing gas burners 11. The valves 22, 25 may be adapted for automatic co-operation in the same manner as the valves 31 described below. A worm 16 conveys the material through the chamber 4 and air &c. under pressure is circulated therethrough, preferably in countercurrent to the material, by means of pipes 20, the air leaving the chamber being recirculated, if desired, with addition of fresh oxygen-bearing gas. The red lead formed is discharged through a valve 31 into an intermediate chamber from which a second valve 31 passes it to a chamber 38, the valves 31 being automatically operated from a cam shaft 33 in such manner that they are never both open at the same time. Automatically-controlled valved pipes may be provided to equalize the pressures in the intermediate chambers above referred to with that in the reaction chamber prior to each opening of the valve 25 and the upper valve 31, and to connect the intermediate chambers to atmosphere after the closing of these valves and prior to each opening of the valve 22 and the lower valve 31. Residual gas from the chamber 38 is passed through a silencer 41.