WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
47.04 Chemical wood pulp, sulphite, other than dissolving grades. - Unbleached : 4704.11 - - Coniferous - Semi-bleached or bleached : 4704.2 1 - - Coniferous The s u ~ h i t eprocess generally employs an acid solution and takes its name fiom the various sul hite " chemicals, such as calcium bisulphite (calcium hydro en sul hite), magnesium gisulphite (magnesium hydrogen sulphite), sodium bisulphite (so urn hy ogen sulphite), ammonlum bisul hite (ammonium hydrogen sulphite), which may be used during the preparation of the cooking fquor (see the Explanatory Note to heading 47.02). The solution also contains fiee sulphur dioxide. The process is used extensively for the treatment of spruce fibre. d 6: Sulphite pulp is used, alone or mixed with other pul s, for various writing or printing papers, etc. It is also used, inter alia, for greaseproof or glaze transparent papers. B 47.05- Wood pulp obtained by a combination of mechanical and chemical pulping processes. z Tbis heading covers wood ulp manufactured b a combination of mechanical and chemical pulping processes. Such pufp is variously descri ed as semi-chemical pulp, chemi-mechanical pulp, etc. semi-chemical. is produced in a two-part process in which the wood, generally in chips, is ened in digesters and then mechanically refined. It contains a great deal of and is us@ main1 for medium-quality papers. It is general1 semi-chermcal &sc), bisulph~te semi-chemical or krart Chemi-mechanical pulp is produced in refiners from wood in chips, shavings, sawdust or similar forms. The wood is reduced to a fibrous state by the abrasive action induced by two closely spaced ridged plates or discs, one or both of which are rotating. Small amounts of chemicals are introduced as a re-treatment or during reflning in order to facilitate fibre separation. The wood may be su jected to steaming for different periods of time at different pressures and tern eratures. De ending on the combination of processes employed in its manufacture, and t e order in w ch the processes are carried out, chemi-mechanical ulp is also known as chemi-thennomechanical pulp (CTMP), chemi-refiner mechanical pulp ( RMP) or thermo chemi-mechanical pulp (TCMP). R Li E Chemi-mechanical pulps are used, inter aha, in the production of newsprint (see Note 4 to Chapter 48). They are also used for making tissue and graphic paper. The heading includes pulps known as screenings.
Pulp of wood or of other fibrous cellulosic material; recovered (waste and scrap) paper or paperboard Note. 1.- For the purposes of heading 47.02, the expression " chemical wood ul , dissolvin grades " means chern~calwood ul having by weight an insoluble ftaction of 9! or m e z r soda or sulphatc wood pulp or o p 8 f % or more for rulphite wood ulp afkr one hour in s caustic soda solution containing 18 % sodium hydroxide (NaOH) at 20 'C, anifor sulphite wood pulp an ash content that does not exceed 0.15 % by weight. GENERAL The pul of this Chapter consists essential1 of cellulose fibres obtained from various vegetable materiaf's, or fiom waste textiles of vegetab e origin. Y The most important pulp in international trade is wood pulp, termed "mechanical wood pulp", "chemical wood pulp", 'semi-chemical wood pulp" or ' chemi-mechanical pulp", according to its method of preparation. The woods mostly used are pine, s ruce, oplar and aspen, but harder woods such as beech, chestnut, eucalyptus and certain tropic woo are also used. 8 & Other materials used for making pulp include : (1) Cotton linters. (2) Recovered (waste and scrap) paper or paperboard. (3) Rags (particularly cotton, linen or hemp) and other textile wastes such as old ropes. (4) Straw, esparto, flax, ramie, jute, hemp, sisal, bagasse, bamboo and various other grasses and reeds. or white. It may be semi-bleached or bleached by chemicals or may should be regarded as semi-bleached or bleached if, after manufacture, it treatment Intended to increase its degree of whiteness (brightness). Apart from their use in the paper indus some pulps (especially bIeached pulps serve as a source of cellulose in the manufacture o various products such as artificial texti e materials, plastics, varnishes and explosives; they may also be used in cattle fodder. "r. I' Pulp is generally presented in baled sheets (whether or not perforated), wet or dry, but may sometimes be in slabs, in rolls or in the form of powder or flakes. The Chapter does not cover : (a) Cotton linters (heading 14.04). (b) Synthetic a er pulps consisting of sheets of non-coherent polyethylene or polypropylene fibres (heading &b. (c) Fibreboard (heading 44.11). (d) Filter blocks, slabs or plates, of paper pulp (heading 48.12). (e) Other articles of paper pulp (Chapter 48).