Mechanical pulping and chemical pulping are two different methods used to extract fibers from wood or cellulosic raw materials for the production of paper and other fibrous products. They differ in processing, fiber properties and applications.
1. Mechanical Pulping:
Mechanical pulping is a method of separating the fibers in wood by physical force. It mainly separates the fibers of the wood by mechanically crushing and grinding the wood. The main features of this method are the fast production speed and the ability to retain longer fibers, but at the same time it can lead to fiber breakage and shortening. Because the fiber is impacted by mechanical force during the mechanical pulping process, the pulp produced is usually rough, which is suitable for making some rough paper or cardboard.
2. Chemical pulping:
Chemical pulping extracts fibers by using chemicals to break down lignin and other non-fibrous components of wood. The most common chemical pulping methods are sulfuric acid method (kraft method) and phosphoric acid method (sulfite method). These chemical pulping methods separate the fibers better, resulting in longer and stronger fibers. Since non-fibrous components such as lignin are removed, the pulp produced by chemical pulping is suitable for making high-quality paper, such as writing paper, toilet paper, etc.
- Mechanical pulping is suitable where high speed, low cost and relatively long fiber lengths are required, but produces a coarser pulp quality.
- Chemical pulping is suitable for situations where high-quality paper, high fiber strength and stability are required, but the pulping process is relatively complex and costly.
Which pulping method to choose usually depends on factors such as the quality standard of the desired product, production efficiency and raw material availability.