GB775378A - Improvements in or relating to pelleting carbon black and apparatus therefor - Google Patents

Abstract

In the granulation of hot carbon black, e.g. at a temperature of 150-300 DEG F., in a rotating mill, sufficient water, e.g. 2-24 per cent, is sprayed into the mill to produce <PICT:0775378/III/1> a granulated product at a temperature of 100-225 DEG F., but insufficient to produce a water content of greater than 1 per cent. The water may contain a wetting agent, e.g. one listed in Ind. Eng. Chem. Vol. 33, No. 1, pages 16-22 and Vol. 35, No. 1, pages 107-117 and 126-130. Water vapour may be withdrawn from the mill during the spraying. The rate of flow of spraying water may be regulated in response to deviations in temperature of the granulated product. As shown a rod 17 supported on piers (not shown) outside the mill passes axially through the mill. It supports spray head 19, a scraping device (not shown) and exhaust line 22. Loose black is delivered to the mill direct from a carbon black furnace via hopper 27 and the granulated product passes through openings 31. The delivery end of mill 11 is covered by a gas tight hood 33 which is connected to a screen 36. Material passing through the screen is recycled to the process via conveyer 39, while the desired product is passed along a conveyer in a housing 38 and then through an elevator and shoot to a storage tank (not shown). Three alternative means for exhausting the water vapour are shown, i.e. from the mill 11 via line 22, from the hood via line 20, and from the elevator housing 38 via line 61. The exhausted vapour passes to a blower 56 and a filter 57, carbon black fines being recycled to the process via line 58. Mill hood 33 may also be vented directly to the atmosphere via line 20b. A solenoid 51 cuts off the flow of water when the motor 14 stops and a valve 52 should the pressure of water drop below a certain minimum (e.g. due to leakage in the mill).