The separation of fibers can generally be divided into three methods, namely mechanical method, chemical method and other methods (including microbial method, organic solvent method, blasting method, etc.). This article mainly introduces the first two methods.
1. Mechanical method
The process of the mechanical method is to press the wood section (the wood is peeled and sawn into a certain length specification) on a rapidly rotating millstone (with grooves carved on the surface), and the heat energy generated by mechanical friction will make the wood in the wood When the lignin is softened, it is peeled off layer by layer, and after regrinding, it becomes pulp. The pulp produced in this way is called ground wood pulp or mechanical wood pulp or ground wood pulp.
Ground wood pulp can be used to produce newsprint after being matched with mouse-less chemical wood pulp.
2. Chemical method
If we cook raw materials (wood), chemicals, etc. under certain conditions, the resulting pulp is called chemical pulp.
The commonly used chemical methods mainly include sulfate method (alkali method), sulfite method and neutral sulfite method. For example: the sulfate method is named after using a mixture of sodium hydroxide and sodium sulfide (commonly known as soda sulfide) to cook raw materials, and using sodium sulfate (glauber's salt) as a supplement . The cost of kraft pulping is relatively low (the chemicals and heat energy after cooking can be recovered and utilized), the cooking time is short, the pulp yield is high, and the strength is good. The sulfite method is referred to as the sulfite method or the acid method.
