WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
74.01 - Copper mattes; cement copper (precipitated copper). (A) Copper mattes. This is obtained by the fusion of roasted sul hide from the gangue and the other of P,e matte. The matte consists essentially of copper and the form of black or brown granules (obta~nedby pouring crude mass, with a dull, metallic appearance. and is generally in into water) or a (B) Cement copper (precipitated copper). Cement co per (precipitated copper) is a product obtaiaed b preci itation (cementation), i.e., by adfing iron to the aqueous solution resulting from t e leac mg of certa$ roasted ores or residues. It is a finely divided black powder containin oxldes and insoluble impurities. It is sometimes used in anti-fouling paints and agricu tural fungicides but is more often added to the charge which goes to a melting furnace to produce copper matte. K 1. S Cement copper must not be confused with the copper powder of heading 74.06, which does not contain impurities.
Note. 1.- In this Chapter the following expressions have the meanings hereby assigned to them : (a) Refined copper Metal containing at least 99.85 % by weight of copper; or Metal containing at least 97.5 % by weight of copper, provided that the content by weight of any other element does not exceed the limit specified in the following table : TABLE - Other elements Element Limiting content % by weight Ag Silver 0.25 As Arsenic 0.5 Cd Cadmium 1.3 Cr Chromium 1.4 Mg Magnesium 0.8 Pb Lead 1.5 S Sulphur 0.7 Sn Tin 0.8 Te Tellurium 0.8 Zn Zinc 1 Zr Zirconium 0.3 Other elements*, each 0.3 * Other elements are, for example, Al, Be, Co, Fe, Mn, Ni, Si. (b) Copper alloys Metallic substances other than unrefined copper in which copper predominates by weight over each of the other elements, provided that : (i) the content by weight of at least one of the other elements is greater than the limit specified in the foregoing table; or (ii) the total content by weight of such other elements exceeds 2.5 %. (c) Master alloys Alloys containing with other elements more than 10 % by weight of copper, not usefully malleable and commonly used as an additive in the manufacture of other alloys or as de-oxidants, de- sulphurising agents or for similar uses in the metallurgy of non-ferrous metals. However, copper phosphide (phosphor copper) containing more than 15 % by weight of phosphorus falls in heading 28.53. Subheading Note. 1.- In this Chapter the following expressions have the meanings hereby assigned to them : (a) Copper-zinc base alloys (brasses) Alloys of copper and zinc, with or without other elements. When other elements are present : - zinc predominates by weight over each of such other elements; - any nickel content by weight is less than 5 % (see copper-nickel-zinc alloys (nickel silvers)); and - any tin content by weight is less than 3 % (see copper-tin alloys (bronzes)). (b) Copper-tin base alloys (bronzes) Alloys of copper and tin, with or without other elements. When other elements are present, tin predominates by weight over each of such other elements, except that when the tin content is 3 % or more the zinc content by weight may exceed that of tin but must be less than 10 %. (c) Copper-nickel-zinc base alloys (nickel silvers) Alloys of copper, nickel and zinc, with or without other elements. The nickel content is 5 % or more by weight (see copper-zinc alloys (brasses)). (d) Copper-nickel base alloys Alloys of copper and nickel, with or without other elements but in any case containing by weight not more than 1 % of zinc. When other elements are present, nickel predominates by weight over each of such other elements.