The balling rate is up to 70%, there is a small amount of returned material, and the returned material has small particle size, which can be re pelleted; Through steam heating, the material temperature is increased, so that the water content of the material after pelleting is low, and the drying efficiency is improved; The rubber engineering plastics are used as the lining, so the raw materials are not easy to stick to the cylinder and play the role of anti-corrosion and thermal insulation; Large output, low power consumption and low maintenance cost.