Method for forming carbon black pellets of high density

摘要

Finely-divided carbon black, such as channel black, impingement black, or furnace black, is formed into free-flowing beads or pellets having such a density that 50 pounds thereof occupies not more than 1.5 cubic feet, by (a) agitating the finelydivided black with water to form preliminary beads, the amount of the water being 35-45 per cent based on the weight of the black-water mixture; (b) subjecting the said beads to the action of closelyspaced rotating members submerged in a mass of the agglomerates, the members rotating in a single unpartitioned mixing chamber at a speed of about 300 to 400 r.p.m.; and (c) removing water from the resultant final beads. Prior to step (a) the black may be densified. As shown, carbon black and water are mixed in chamber 1 to form preliminary beads, which fall through an opening 8 into a chamber 9 where they are formed into the final beads or pellets and whence they are discharged through a gated opening 13. The chamber 1 includes a carbon-blackfeed opening 5, a water inlet 6 a mixing shaft 2 rotating at 150 r.p.m. and having pins 4 which form two double helices 90 degrees apart, and a clam 7. The chamber 9 includes three mixing shafts 10 rotating preferably at 300-360 r.p.m., each shaft having a double helix of pins 9a. The pins may be reinforced by braces 16 secured thereto and to the shafts 10. The level of the material in chamber 1 is shown at X and the level in chamber 9 at Y. Specifications 754,207 [Group V] and U.S.A. Re-issue 21,379 are referred to.