Waste products and undeveloped substances : a synopsis of progress made in their economic utilisation during the last quarter of a century at home and abroad / by P.L. Simmonds.

Date:: 1873

Credit: Waste products and undeveloped substances : a synopsis of progress made in their economic utilisation during the last quarter of a century at home and abroad / by P.L. Simmonds. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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$the manufacture of sulphuric acid, or oil of vitriol as it is sometimes called. As, on account of the little sulphur left in It, the burnt pyrites is unfitted for manufacture into iron, it was long suffered to accumulate in huge heaps; but now, thanks to the progress of chemistry, about 9600 tons of copper ore are obtained from 350,000 tons of the pyrites. Under the ingenious processes of Claudet and Phillips, carried on at the works of the Lancashire Metal Extracting Company, silver and gold worth 3,700Z. were extracted in 1871, the sole cost being that of extraction. The expensive element, iodine, employed in the production of silver, is recovered and used over and over again, with little waste, and the loss of zinc is compensated by the lead recovered. From the washings of the mixture of burnt pyrites and salt, after the silver has been precipitated, copper is ob- tained, being deposited upon scrap iron of all kinds cast into the solution. The copper is separated from the iron by sieves, and, when washed and drained, is sold to the smelters. Upwards of 9000 tons were smelted in 1871. Formerly the remaining solution of sulphate and chloride of iron, with excess of common salt, was thro-mi into sewers or canals; but now, from the injurious waste, che- mical treatment obtains a sulphate of soda which is used in the manufacture of glass, while the undissolved oxide of iron is sold as rouge of the first quality. Yet, although so many valuable products are obtained from this waste pyrites, much still remains to be done. The mode of extracting coi^per from pyrites residues practised in the Tyne district is thus described by ]\Ir. G. Lange. The pyrites, after having been used for the manu- facture of sulphuric acid, are washed with the addition of 7^ per cent, or more of salt, the gases fiom this washing being condensed and used for the lixiviation of the roasted mass, which consists of copper and sodic sulphates, and copper and iron oxide, and the copper reduced out of the solution by the use of iron sponge, as already shown. In 1870 there were about twenty works in action in the United Kingdom for extracting metal from Sj^anish and other coppery pyrites, the consumption of burnt ore being 200,000 tons. About 10 per cent, of the oxide of iron, known as$