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Chapter 78 : Lead and articles thereof
Subheading Note. 1. In this Chapter the expression "refined lead" means :
Metal containing by weight at least 99.9 % of lead, 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
As Arsenic
Bi Bismuth
Ca Calcium
Cd Cadmium
Cu Copper
Fe Iron
S Sulpur
Sb Antimony
Sn Tin
Zn Zinc
Other (for example Te), each | 0.02
0.005
0.05
0.002
0.002
0.08
0.002
0.002
0.005
0.005
0.002
0.001 |
GENERAL
This Chapter covers lead and its alloys, and certain articles thereof.
Lead is mainly extracted from galena, a natural lead sulphide ore often containing silver. The crushed ore, after concentration by flotation, is generally roasted or sintered, and is then reduced by smelting. During the roasting or sintering process, the sulphide is largely converted into oxide; in the smelting process, the oxide is reduced to lead by means of coke and a flux. In this manner "bullion lead" or "work lead" is obtained; this contains a number of impurities, frequently including silver. It is therefore generally further refined to produce almost completely pure lead.
Lead is also obtained by remelting lead waste and scrap. Lead is a heavy, bluish-grey metal; it is very malleable, easily melted and very soft (it can be marked easily with the thumb nail). It resists the action of most acids (e.g., sulphuric acid or hydrogen chloride) and is therefore used in the construction of chemical plant. Because of its low melting point lead is easily alloyed with other elements. The principal lead alloys which may fall in this Chapter under the provisions of Note 5 to Section XV (see the General Explanatory Note to that Section), are the following : (1) Lead-tin alloys used, for example, in lead-based soft solders, in terne-plate and in foil for the packing of tea. (2) Lead-antimony-tin alloys used for printing type and in anti-friction bearings. (3) Lead-arsenic alloys used for lead shot. (4) Lead-antimony alloys (hard lead), used for bullets, accumulator plates, etc. (5) Lead-calcium, lead-antimony-cadmium, lead-tellurium alloys. The Chapter covers : (A) Unwrought lead and waste and scrap (headings 78.01 and 78.02). (B) Products generally obtained by rolling or extruding the unwrought lead of heading 78.01 (headings 78.04 and 78.06); lead powders and flakes (heading 78.04). (C) Tubes, pipes and fittings and the other articles of the residual heading 78.06 which covers all other lead articles other than those covered by Note 1 to Section XV or included in Chapter 82 or 83 or those more specifically covered elsewhere in the Nomenclature. Products and articles of lead may be subjected to various treatments to improve the properties or appearance of the metal, etc. These treatments are generally those referred to at the end of the General Explanatory Note to Chapter 72, and do not affect the classification of the goods. The classification of composite articles is explained in the General Explanatory Note to Section XV.
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