The Monteponi Company smelts its own zinc, but the lead is almost all smelted at the furnaces of Pertusola near Spezia.
Copper is smelted in Ardennes and Pas-de-Calais.
These ores were worked by the ancients, but so inefficiently that their spoilheaps can be smelted again with profit.
Lead ores are smelted in the reverberatory furnace, the ore-hearth, and the blast-furnace.
While by the English and Carinthian processes as much lead as possible is extracted in the furnace, with the Silesian method a very low temperature is used, thus taking out about one-half of the lead and leaving very rich slags (50% lead) to be smelted in the blast-furnace, the ultimate result being a very much higher yield than by either of the other processes.
Thus, a mixture of lead sulphate (45%) and oxide (44%) with some sulphide (8%), zinc and carbonaceous matter, is agglomerated by a heap-roast and then smelted in a slag-eye furnace with grey slag from the ore-hearth.
Ores are smelted raw if the fall of matte (metallic sulphide) does not exceed 5%; otherwise they are subjected to a preliminary oxidizing roast to expel the sulphur, unless they run too high in silver, say 100 oz.
To the ton, when they are smelted raw.
The Yzerberg near Marabastad in the Zoutpansberg consists of exceedingly rich iron ore, which has been smelted by the natives for many centuries.
The dressed ore is smelted with carbon by one of two main methods, viz.
Either in the shaft furnace or the reverberatory; the former is the better suited to stream tin, the latter to lode tin, but either ore can be smelted in either way, although reverberatory practice yields a purer metal.
The ore is smelted at Lubumbashi, where in 1918 were seven furnaces with a producing capacity of 40,000 tons a year.
In Colorado the pyritic ores containing gold and silver in association with copper are smelted in reverberatory furnaces for regulus, which, when desilverized by Ziervogel's method, leaves a residue containing 20 or 30 oz.
This is smelted with rich gold ores, notably those containing tellurium, for white metal or regulus; and by a following process of partial reduction analogous to that of selecting in copper smelting, " bottoms " of impure copper are obtained in which practically all the gold is concentrated.
Sulphuretted ores are smelted, either with or without a preliminary calcination, with metallic iron; calcined ores may be smelted with carbon (coal).
The ore of the metal occurring in the Mississippi basingalena----is scattered widely and in large quantities, and being easily smelted by the roughest possible methods was much used at an early date.
Magnetites were also early employed, at first in Catalan forges, in which by means of a direct process the metal was secured from the ores and forged into blooms without being cast; later they were smelted in blast furnaces.
The total refined domestic product in 1907 was 337,340, and the total domestic lead smelted was 365,166 tons.
Of the soft lead smelted in 1907 no less than 94.8% came from Missouri.
Iron is found in eastern Tibet in the form of pyrites, and is rudely smelted locally.
Iron is found in many districts and is smelted in a few places.
Iron is smelted by the natives, who, especially amongst the Hausas, are very clever smiths, and manufacture fine lances and arrow heads, knives and swords, and also hoes.
The process adopted for the Canadian ores, which are poor in copper and nickel, consists in a preliminary roasting in heaps and smelting in a blast furnace in order to obtain a matte, which is then further smelted with a siliceous flux for a rich matte.
This iron needed no tempering, and the Celts had probably found it ready smelted by nature, just as the Eskimo had learned of themselves to use telluric iron embedded in basalt.
South Bethlehem is the see of a Protestant Episcopal bishop. The Bethlehem Steel Company manufactures here iron and steel, including Bessemer steels, armour plate, steel rails, government ordnance, drop forgings, iron and steel castings, stationary engines, gas engines, hydraulic pumps, projectiles, steel shaft and pig iron; zinc is smelted and refined; and there are large hosiery and knitting mills, and silk mills and cigar factories.
The iron mines of Elba, and the tin and copper of the mainland, were owned and smelted by the people of Populonia; hot springs too lay some 6 m.
The Federal census of 1900 credited the manufacturing establishments of the state with a capital of $62,825,472 and a product of $102,830,137 (increase 1890-1900, 142.1%); of which output the gold, silver, lead and copper smelted amounted to $44,625,305.
Native copper, sometimes termed by miners malleable or virgin copper, occurs as a mineral having all the properties of the smelted metal.
The roasted ore is then smelted to a mixture of copper and iron sulphides, known as copper " matte " or " coarse-metal," which contains little or no arsenic, antimony or silica.
The coarse-metal is now smelted, with coke and siliceous fluxes (in order to slag off the iron), and the product, consisting of an impure copper sulphide, is variously known as " blue-metal," when more or less iron is still present, " pimplemetal," when free copper and more or less copper oxide is present, or " fine " or " white-metal," which is a fairly pure copper sulphide, containing about 75% of the metal.
This product is re-smelted to form " coarse-copper," containing about 95% of the metal, which is then refined.
Roasted ores may be smelted in reverberatory furnaces (English process), or in blast-furnaces (German or Swedish process).
After the ore has been partially calcined, it is smelted to extract its earthy matter and to concentrate the copper with part of its iron and sulphur into a matte.
In reverberatory furnaces it is smelted by fuel in a fireplace, separate from the ore, and in cupolas the fuel, generally coke, is in direct contact with the ore.
When Swansea was the centre of the copper-smelting industry in Europe, many varieties of ores from different mines were smelted in the same furnaces, and the Welsh reverberatory furnaces were used.
8 in., and smelted 12 tons of cold charge daily, with a consumption of 1 ton of coal to 2.4 tons of ore.
At Tilt Cove, Newfoundland, the Cape Copper Company smelted copper ore, with just the proper proportion of sulphur, iron and silica, successfully without any fuel, when once the initial charge had been fused with coke.
Austin, of Denver, Colorado, and both at Leadville and Silverton raw ores are successfully smelted with as low a fuel consumption as 3 of coke to zoo of charge.
In stoves heated by extraneous fuel, and the raw ore smelted with only 3% of coke.
It is smelted raw with hot blast in cupola furnaces, the largest being 2 10 in.
If it contains more than 55% of copper it is directly refined, while if it contains a lower percentage it is smelted with matte or calcined copper pyrites.
In the Joplin mining region a considerable amount of ores is smelted, but the bulk of the ores is sent into Kansas for smelting.
It was known and smelted by British and Romans, and by the monks of Furness Abbey and Conishead Priory, both in the district.
Here, too, are a plant (covering more than Boo acres) of the Standard Oil Company and a large establishment for the manufacture of the "Singer" sewing machine - according to the U.S. census the largest manufactory of sewing machines in the world - employing more than 6000 workmen in 1905; among the other manufactures of Elizabeth are foundry and machine shop products (value in 1905, $3,887,139), wire, oil (value in 1905, $2,387,656), refined and smelted copper, the output of railway repair shops, edge tools and lager beer.
Blast furnaces are, from the intimate contact between the burden to be smelted and the fuel, the least wasteful of heat; but their use supposes the possibility of obtaining fuel of good quality and free from sulphur or other substances likely to deteriorate the metal produced.