Method for recycling nitrile rubber

A method of recovering nitrile rubber from water-containing crumbs comprising crumb-like nitrile rubber using an extruder in which a screw is disposed inside a barrel so as to be capable of being rotationally driven, the barrel being formed with at least a washing/dewatering zone, the method comprising

• supplying washing water to the washing/dewatering zone at a water pressure of 0.2 MPa or higher while mixing the crumb-like nitrile rubber and the supplied washing water in the washing/dewater zone, thereby washing and dewatering the crumb-like nitrile rubber,
• wherein
• the screw for use comprises a kneading disk provided at a site corresponding to a supply position for the washing water,
• the extruder for use has a plurality of barrel blocks, and
• a screw configuration of the screw in a barrel block formed with a supply port for supplying the washing water is such that a fraction occupied by the kneading disk in a longitudinal direction is within a range from 70% to 100%, and
• wherein the nitrile rubber contains chlorine in a content of 711-1112 ppm by weight and sodium in a content of 461-721 ppm by weight.