Paper mills generally need to store enough raw materials for 4 to 6 months so that raw materials can be naturally fermented during storage to facilitate pulping and ensure continuous production at the paper mill. Raw materials such as reeds, wheat straw, and wood are cut into pieces (for producing chemical pulp) or wood chips (for producing wood pulp) in the preparation section. The small pieces of raw materials are put into the digester and added with chemical liquid, and steam is used for cooking. , The raw material is boiled into pulp, or the wood is cut off and ground into a pulper to grind pulp. It can also be cooked to a certain degree and ground into pulp. The pulp is then washed with a large amount of fresh water, and the coarse pieces, knots, stones, sand, etc. in the slurry are removed by screening and purification. According to the requirements of the paper, the bleaching agent is used to float the pulp to the desired degree of whiteness, followed by beating with a pulping apparatus. Then, various auxiliary materials, such as fillers, rubber compounds, and sizing agents, which improve the performance of the paper, are added to the pulp, and are purified and screened again. Finally, they are sent to the paper machine for filtering through the net, dehydration by pressing, dryer drying, and calendering. Take, and cut, rewind, or cut to produce web and flatbed paper. If production is to produce coated printing paper, it is necessary to dry the middle or produce a web and apply it after coating.
In addition to the above basic process, it also includes some auxiliary processes, such as preparation of cooking liquor, preparation of bleaching liquor, tanning of rubber compound, and recovery of chemicals and thermal energy in cooking waste liquid and exhaust gas.