VALUABLE MINERALS

Te Awamutu Courier, Volume 53, Issue 3843, 7 December 1936, Page 6

VALUABLE MINERALS

THE RELATIVE IMPORTANCE OF LEAD. If a man were told that he was to be deprived, one by one, of the metals he uses, we may be quite certain that the last to be retained would be iron. What metal would he retain next—copper, tin, lead, aluminium, zinc? The importance of electricity would do much to favour the retention of copper, although aluminium and lead would receive serious consideration. The iron manufacturer, remembering how much of his product is enhanced in value by being coated with tin or zinc, would seriously consider these two, giving the preference probably to zinc. It seems likely, however, that after full consideration, the numerous uses of lead would ensure its retention as long as possible. A study of statistics as to amounts used may be useful as a guide to relative importance. In 1934 the amounts produced were roughly—iron, 81,000,000 tons; copper and lead, each about one million and a third; zinc, one million and one-seventh; aluminium, one-sixth of a million; and tin, one-ninth of a million.

These figures do not tell the full story of the amounts actually needed to supply a year’s demand, since much metal, particularly in the cases of iron, copper and lead, is recovered as scrap and used again. Exact estimates are not available, but more than 200,000 tons, roughly one-sixth of the total lead used, is recovered metal. It is interesting to note that Australia comes second on the list of producers, her output of lead being somewhat more than 200,000 tons. The question of costs and price would also have some influence on the decision concerning general usefulness, and in this respect lead would again be in a favourable position. The prices per ton are, roughly, tin £2OO, aluminium £lOO, copper £4O, lead £l7, and zinc £l3. VERY VALUABLE PROPERTY. The Anal choice would depend, however, mainly on the possession by the chosen metal of certain specific characteristics more or less absent in the others. One very valuable property of lead is its durability. Thus lead water pipes dating from at least 1000 years back are occasionally found, and it is safe to say that no other metal, except perhaps tin, would have resisted corrosive influences for so long. Its general resistance to chemical attack is valuable also to the manufacturing chemist. Sulphuric acid is the most important of big scale chemicals, and at least half the acid produced is made in apparatus, the main part of which is a series/of huge rooms of which the whole of the interior is lined with lead—no other metal is suitable. Its resistance to sulphuric acid also helps to explain its extended use in electric storage batteries. Its pliability and resistance to atmospheric attack make it an excellent roofing material. Such roofs will last for centuries. Lead has been known from very early times, its areas are abundant, and the metal is easily obtained from them by a comparatively simple smelting process. This centuries old familiarity crops up in familiar expressions in our ordinary language; we comprehend at once such expressions as “a plumb line,” “heavy as lead,” “a leaden sea (or sky.)” The general importance of the usefulness of the metal is shown by the fact that the words plumbing and plumber apply to a particular craft in a rather distinctive way, plumbers being the only set of workers in metals who are not included in the extensive group of smiths, as, for example, are coppersmiths or goldsmiths. The alchemists of the middle ages, for some obscure reason, associated lead with the planet Saturn, just as silver was associated with the moon, or iron with Mars. From this association we derive our adjective saturnine—dull and heavy of countenance.— Dr W. T. Cooke, in Melbourne Age.