Manufacture of paste and paper outline and history origin China

It is believed that papermaking originated in China around 100 AD: rags, cannabis, straw and grass were used as raw materials and were beaten against stone mortars to separate the original fiber. Although mechanization gained ground over time, until the 19th century, batch production methods and agricultural fiber sources continued to be used. The first continuous paper machines were patented in the years of change from the 19th to the 20th century. Between 1844 and 1884 the first methods were developed to obtain wood pulp, a more abundant fiber source than rags or herbs; These methods involved mechanical abrasion and the application of chemical processes based on caustic soda, sulphites and sulfates (Cellulose to sulphate). With these changes began the modern era of the manufacture of pasta and paper.http: //thechemistrysideoftheforce.blogspot.com/
Figure 72.1 illustrates the most complete pulp and paper manufacturing process of the current era: processing of pulp mechanics; elaboration of paste chemistry; recycled waste paper; papermaking, and transformation processes. Today, the industry can be divided into two large sectors according to the types of products manufactured. The pulp is usually made in large factories located in the same areas where the fiber is harvested (ie the main forest regions). Many of these facilities also manufacture paper (eg, newsprint, writing paper, printing paper or tissue paper) or cardboard. Figure 72.2 shows the scheme of a factory that produces bleached sulphate pulp, thermomechanical pulp and newsprint. Observe the platforms and the loading dock, the chip storage area, the chip conveyor belt to the digester, the recovery buffer boiler (tall white building) and the effluent clarification tanks. The various transformation operations are usually carried out near the consumption centers and use commercial paper or pulp to manufacture bags, cardboard, containers, tissue paper, wrapping paper, decorative stationery, office supplies and the like.
In recent years, there has been a growing tendency for pulp and paper companies to become part of large integrated forest products companies. These companies control forest harvesting operations (see chapter Forestry), sawmills (see the Wood Industry chapter), pulp and paper manufacturing, and processing procedures. A structure thus raised
it guarantees a continuous source of fiber, an efficient use of wood waste and insured buyers, all of which favors an increase in its market share. The integration has developed in conjunction with the growing concentration and globalization, derived from the orientation of companies towards international investments. The financial burden derived from the establishment of industrial plants stimulates this trend to allow economies of scale. Some companies have already reached production levels of 10 million tons, similar to the total capacity of countries with the highest production. Many are multinationals, and some have factories in 20 or more countries around the world. However, even though many of the smaller companies and factories are disappearing, the industry still has hundreds of members. By way of illustration, suffice it to say that the first 150 companies account for two thirds of the production of pulp and paper, and with only one third of the employees.