What Is a Pulp Mill?

Paper pulp (pulp) is a fibrous substance produced by plant fibers as raw materials and processed through different methods. It can be divided into mechanical pulp, chemical pulp and chemical mechanical pulp according to the processing method; it can also be divided into wood pulp, straw pulp, hemp pulp, reed pulp, cane pulp, bamboo pulp, and rag pulp according to the fiber materials used. According to different purity, it can be divided into refined pulp, bleached pulp, unbleached pulp, high yield pulp, semi-chemical pulp and so on. Generally used to make paper and cardboard. Refined pulp is often used as a raw material for cellulose derivatives such as cellulose esters and cellulose ethers, in addition to special paper. It is also used in the fields of man-made fibers, plastics, coatings, films, gunpowder, etc.

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Pulp is some

In 2010, China's paper industry had 146 enterprises above designated size, a year-on-year increase of 2.10%; the total industrial output value reached 32.491 billion yuan, a year-on-year increase of 38.00%; sales income reached 31.749 billion yuan, a year-on-year increase of 40.71%; and total profit reached 2.153 billion yuan.

Most domestic paper companies rely on imports of specialty paper raw materials. In 2010, the strong earthquake in Chile affected 8% of the world's commercial pulp supply and 14% of China's wood pulp imports, and the strike by the papermaking power Finland led to a sharp rise in international special paper prices. The prices of several varieties of papermaking have exceeded High Point. Rising prices for specialty papers have forced papermakers to reduce output and tighten inventory.

This tightening is not expected to reverse in the short term. In the medium and long term, the probability of rising paper prices remains high. From 2011 to 2015, the domestic papermaking capacity that the country intends to put into production reached 46 million tons, and it is expected to add 11.3 million tons of broadleaf pulp demand and 3.8 million tons of coniferous pulp demand. Between 2010 and 2015, the added capacity of broadleaf pulp reached 14 million tons and that of coniferous pulp was 1.5 million tons. However, during 2011-2012, there were not many new wood pulp lines, and most of them were put into production after 2013. Therefore, the megatrend of papermaking prices in 2011-2012 is rising.

International

United States, Canada, Finland, Sweden, Norway, New Zealand, and Chile.

1.Mechanicalwood-PULP

Mechanical wood pulp, also known as ground wood pulp, is a pulp made by mechanically grinding fiber materials. It occupies an important position in the paper industry. It has low production cost, simple production process, strong ink absorption, high opacity, and soft and smooth paper. Suitable for printing requirements. However, due to the short fibers and high content of non-cellulose components, the strength of the paper is low. In addition, because lignin and other non-cellulose in wood are mostly not removed, the paper produced by it is easily yellowed and brittle, and cannot be stored for a long time.

Mechanical wood pulp usually refers to white mechanical wood pulp and brown mechanical wood pulp. White mechanical wood pulp is mainly used in the production of newsprint, and can also be mixed with other pulp to make writing paper and printing paper; brown mechanical wood pulp is mostly used in the production of packaging paper and cardboard, especially industrial cardboard.

2.SULPHATEWOODPULP

Sulfate wood pulp uses sodium hydroxide and sodium sulfide as the cooking agent. In the cooking process, because the action of the liquid medicine is relatively gentle, and the fibers have not been strongly eroded, it is strong and strong. The resulting paper has excellent resistance to folding, tearing and tearing. It can be divided into two types: bleached and unbleached. Unbleached sulfate wood pulp can be used to make kraft paper, paper bag paper, kraft boxboard paper, and general packaging paper and cardboard. Bleached sulphate wood pulp is used in the manufacture of high-grade printing paper, graphic newspapers, offset paper and writing paper.

3.SULPHITEWOODPULP

Sulfite wood pulp is based on the mixture of sulfurous acid and acid sulfite as cooking agent. The pulp has long fibers, soft properties, good toughness, high strength, easy bleaching, and excellent interweaving ability. According to the degree of refining, it can be divided into three types: unbleached, semi-bleached and bleached.

Unbleached pulp has a small amount of lignin and colored impurities, so it is yellow and the fibers are relatively hard. It is mostly used for making medium printing paper, thin packaging paper, translucent paper and greaseproof paper.

The semi-bleached pulp contains a large amount of polypentose, so transparent tracing paper and parchment paper are made.

The fibers of bleached pulp are white, and the texture is pure and soft, but because of bleaching, the fiber strength is lower than that of unbleached pulp. This kind of pulp is mostly used to make various high-quality paper.

4. Waste paper pulp (WASTEPAPERPULP)

Waste paper pulp is made from used waste paper or paper edges cut by printing plants as raw materials, stirred by mechanical force, and bleached or deinked.

The fiber strength and properties of waste paper pulp are determined by the type of pulp used in waste paper. However, because the fiber is again eroded by the chemical solution or damaged by mechanical force, it is worse than the original fiber. According to the quality of waste paper pulp and original waste paper, it is used to make printing paper, writing paper, cardboard and lower grade paper.

In addition to the several types of pulp described above, there are straw pulp, reed pulp, bagasse pulp, bamboo pulp, cotton pulp, hemp pulp, and synthetic pulp.

The main component of the fibers in the pulp is cellulose, in addition to other degrees of hemicellulose, lignin, resins, pigments, pectin and ash. Among them, cellulose and hemicellulose are the basic components required for pulp, and other components are excluded.

There are many performance indicators of pulp, which can be divided into two categories: physical and chemical properties. And physical properties are important indicators for judging the value of pulp, among which tensile strength, burst strength and tear strength are the main evaluation indicators of imported pulp. The larger imports are bleached sulfate wood pulp, unbleached sulfate wood pulp, bleached sulfite wood pulp and mechanical wood pulp.

Imported pulp inspection mainly includes sales weight inspection and physical performance inspection. The inspection standards involved are American Standard (TAPPI), International Standard (ISO), Nordic Standard (SCAN), Australian Standard (APPITA), Canadian Standard (CPPA), etc.

Pulp background

With the improvement of the living standards of the Chinese people and the continuous improvement of the level of papermaking technology, China's paper products have shown a trend of high-end and diversification. Imported paper products have a trend of further high-end, while domestic paper products have further expanded their product lines, gradually filling many previous gaps, and the proportion of demand for high-quality long fibers has also gradually increased.

Changes in pulp structure

Although the integration of forestry pulp and paper is an important way for China's paper industry to solve the bottleneck of raw wood pulp supply and improve the quality and competitiveness of paper products, due to population pressure, limited forest land resources, higher investment capital for integrated projects, longer log supply cycles, etc. And many other unfavorable factors, China's forest-paper integration project will be difficult to reach the level of contribution to the corresponding industries in Canada, Finland and other countries in the next few years. Therefore, relying solely on afforestation to increase the proportion of raw wood pulp in the pulp of the Chinese paper industry is very difficult in the short term. Although the proportion of raw wood pulp in pulp has not changed much, the proportion of waste pulp has increased year by year.