GB1276262A - Process for producing rubber crumbs - Google Patents

Abstract

1276262 Rubber crumbs METALLGESELLSCHAFT AG 25 March 1970 [29 March 1969] 14447/70 Heading C3E Rubber crumbs are produced by a process in which an acid natural or synthetic rubber coagulum mixture is rendered alkaline by addition of an alkali metal hydroxide, the alkaline mixture is centrifuged. The resulting sediment is dried in a rotary drier in contact with hot gas which is inert to the rubber, the dried material is subjected to dust-removing treatment in a diffusion chamber and the dry product from which dust has been removed is comminuted to a maximum particle size of 3À0 mm. The coagulum in the coagulum mixture is preferably comminuted to a particle size below 10 mm. The content of coagulum in the mixture is preferably adjusted to be below 15% by weight, more preferably 10-12% by weight. The pH is preferably adjusted to be 7À5-9. The sediment formed in the centrifuge may be washed therein by rinsing with water. In the diffusion chamber the dry product is separated from the drying gas, which is exhausted by a suction blower and entrains the fire dust. This dust is removed from the exhausted drying gas in a cyclone and the gas is then recycled to a point which precedes the rotary dryer.