1. Mixing:  
When using an open mill for mixing, it is best to equip a dust-proof or exhaust device above the roller of the open mill to reduce the flying of white carbon black. During the mixing process, no other impurities or rubber particles should be mixed in, the temperature should be controlled below 40 ℃, and enough cooling water should be used. It is slower to mix and eat powder in the open mixer, and the mixing time of each batch of rubber is about 20-40min. Mixing with an internal mixer can not only improve production efficiency and reduce labor intensity, but also reduce the flying of white carbon black and improve the operating environment. 

The mixing operation sequence of internal mixer is basically similar to that of open mixer, but the requirements for interval time are not strict. The mixing time of each batch of rubber is about 8-18 minutes, and the filling factor of the internal mixer should be controlled within the range of 0.7-0.75. The debinding temperature is related to the type of filler, and should usually be controlled within the range of 50°C to 70°C. 

2. Heat treatment:  

When the fumed silica without surface modification is used as a reinforcing agent, a structure control agent must be added to the rubber compound. Therefore, the heat treatment of the rubber compound has become a necessary process. The main purpose of the heat treatment is to further combine the structure control agent with the white carbon black surface (Si-OH) and eliminate low molecular volatiles in the glue. The general heat treatment conditions are: under the protection of nitrogen or in a kneader under reduced pressure at 160°C to 200°C for 1 to 1.5 hours. 

3. Filter:  
For extruded products, calendered products, rubber-coated products, and film products, mechanical impurities and undispersed compounding agent particles are one of the main factors leading to product quality problems. Therefore, the rubber materials used in the above products must be filtered. A rubber strainer can be used for filtering or an ordinary extruder can be used instead. The temperature of the barrel and screw should be controlled to the minimum, and the filter screen size should be 120-200 mesh. 

4. Refining:  
After the rubber is parked, the gel content increases and the plasticity decreases, so it must be re-mixed during use. The re-smelting of the rubber should be adequate. If the re-smelting is insufficient, the rubber has poor flexibility and uneven surface; and if the re-smelting is too much, the surface of the rubber will become sticky, which is not conducive to operation.