Patent GB-1022988-A (GB)
Title: Method of treating carbon black
IPC: C09C1/56
Filed: 1964-09-01
Abstract: A continuous process for modifying the properties of carbon black by attrition in an enclosed system comprises continuously passing a stream of black, in either powder or pellet form, through an attrition mill wherein the black is subjected to the attritioning action of hardsurfaced objects, continuously recovering without classifying one portion of the attrited black as product, continuously recirculating another portion of the attrited black to the mill, and continuously charging unmodified black to the mill, the continuous stream of black being thus constituted of recirculated black and black to be modified.  The attrited black is recovered as product from, and recirculated through, and unmodified black is charged to, the mill at predetermined and measured rates, the rate of charging of unmodified black being preferably equal to the rate of recovery of attrited black, and the ratio of the rates of charging of recirculated attrited black to unmodified black being preferably at least 1: 1, especially between 1:1 and 50:1, and advantageously between 2:1 and 40:1.  The attrition mill may be a steel roll or rotary ball mill, but is preferably a vibratory ball mill, in which the hard-surfaced objects may be tungsten carbide steel, forged steel or, advantageously, manganese steel balls.  A gas may be continuously introduced into the enclosed system, preferably at a point proximal to the attrition mill, at a predetermined and measured rate and reacted with the attrited black.  The gas is preferably an oxidizing gas, for example air, advantageously introduced into the system at between 0.5 and 6.0 standard cubic feet per pound of unmodified black charged to the mill, the temperature of the recirculating attrited black being maintained preferably at from 100 DEG  to 500 DEG  F. The gas may also be oxygen, ozone, oxygen-enriched air, oxides of nitrogen or sulphur, halogens or ammonia, and it may be mixed with an inert diluent, for example nitrogen.ALSO:A continuous process for modifying the properties of carbon black by attrition in an enclosed system comprises continuously passing a stream of black, in either powder or pellet form, through an attrition mill wherein the black is subjected to the attritioning action of hard-surfaced objects, continuously recovering without classifying one portion of the attrited black as product, continuously recirculating another portion of the attrited black to the mill, and continuously charging unmodified black to the mill, the continuous stream of black being thus constituted of recirculated black and black to be modified.  The attrited black is recovered as product from, and recirculated through, and unmodified black is charged to, the mill at predetermined and measured rates, the rate of charging of unmodified black being preferably equal to the rate of recovery of attrited black, and the ratio of the rates of charging of recirculated attrited black to unmodified black being preferably at least 1 : 1, especially between 1 : 1 and 50 : 1, and advantageously between 2 : 1 and 40 : 1.  The attrition mill may be a steel roll or rotary ball mill, but is preferably a vibratory ball mill, in which the hard-surfaced objects may be tungsten carbide steel, forged steel or, advantageously, manganese steel balls.  A gas may be continuously introduced into the enclosed system, preferably at a point proximal to the attrition mill, at a predetermined and measured rate and reacted with the attrited black.  The gas, preferably an oxidizing gas, may be, for example, air, oxygen, ozone, oxygen-enriched air, oxides of nitrogen or sulphur, halogens or ammonia, and may be mixed with an inert diluent, for example nitrogen.