Copperas

“ The richest deposits of native copper are those of Lake Superior, in North America. More frequently and more abundantly it occurs as an ore, e.g. red oxide, black oxide, green carbonate of copper or mal′achite, blue carbonate of copper, vitreous sulphide of copper, purple copper, copper pyrites, or yellow copper ore, with sulphur, antimony, or arsenic, and other metals (true grey copper ore or fah′lerz) , as an impure hydrated silicate (chrys′ocolla) , and as an impure hydrated oxychloride (atac′amite) . The most abundant and important ore is copper pyrites. ”

“ Copper may be separated, in a state of great purity, from ANTIMONY, ARSENIC, BISMUTH, LEAD, IRON, TIN, ZINC, &c., as it exists in bell-metal, brass, bronze, gun-metal, mosaic gold, and other commercial alloys, by fusing it in a crucible for about half an hour, along with copper scales (black oxide) and ground bottle-glass, or other like flux. The pure metal is found at the bottom of the crucible, whilst the impurities are either volatilised or dissolved in the flux. The proportions for refining commercial copper are, metal, 10 parts ”

“ While attending to the active and complicated business of the copper-works, making all the assays of ores, fluxes, furnace slags, and of the crude copper produced, he found time to make many interesting and important metallurgical researches, and many scientific observations and [Pg 41] experiments on the formation of artificial minerals, both in the furnace and in the roasting heaps of copper ores. He produced a new mineral, composed of the sulphurets of zinc and copper, which was found in brilliant black crystals in the roasted ores. ”

“ White copper is very brittle; but, if the arsenic be evaporated by heat, it resumes its ductility, and still preserves its white colour. When the operation is well performed, it is easy, at the first glance, to mistake white copper for silver; but the difference may immediately be ascertained from the properties inherent to the two metals.
White copper is employed in the manufacture of many kinds of trinkets: and of a great number of domestic utensils; such as tea-pots, coffee-pots, and candle-sticks. ”

“ In addition to these masses of native copper, an ore of that metal has long been known to the lake traders as the green rock, in which the characteristic substances are the green and blue carbonates of copper, accompanied by copper black. It is situated upon Keweena Point, 280 miles above the falls of the Ste. Marie. The ore is embraced by what is apparently a recently formed crag; and, although it is of a kind and so situated as to make an imposing appearance, there is little certainty of its existence in large quantities in this formation. ”

“ A white crystaline stone is also found to contain a great quantity of yellow copper. The lodes of copper ore generally lie deeper than those of tin, and its ores are mostly of the pyritous and sulphurated kinds, with more or less arsenic. “The lodes, both of tin and copper, appear most frequently to have granite for their country, and to make an angle from 60° to 76° with the horizon.” The matrices of copper ore are very numerous. Among the blue ores, there is one of an extremely fine blue earth. ”

“ Copper exists in considerable quantities in the neighborhood of Dondon and Jacmel, and in the Cibao; silver is found near San Domingo, and in various places in the Cibao, together with cinnabar, cobalt, bismuth, zinc, antimony, and lead in the Cibao, near Dondon and Azua, blue cobalt that serves for painting on porcelain, the gray, black specular nickel, etc.; native iron near the Bay of Samana, in the Mornes-du-Cap, and at Haut-and Bas-Moustique; other forms of that metal abound in numerous places, crystallized, spathic, micaceous, etc. ”

“ A small United-States coin is termed a “nickel.”
Fig. 411.—Native copper.
Copper is the next metal we have to notice. It has been known for centuries. It is encountered native in many places. The Cornish copper ore is the copper pyrites. The fumes of the smelting works are very injurious, containing, as they do, arsenic and sulphur. The ground near the mines is usually bare of vegetation in consequence of the “smoke.” Sheet copper is worked into many domestic utensils, and the alloy with zinc, termed Brass, is both useful and ornamental. ”

“ The ordinary uses of copper are well known. In medicine, 3 or 4 gr. of the filings or powder were formerly given in rheumatism, and to prevent hydrophobia. Some of its salts are still used as astringents, emetics, and caustics. Its alloys are of great value. With zinc it forms BRASS; with tin, BRONZE, BELL-METAL, Gun-metal, and SPECULUM-METAL. White copper is formed by the addition of metallic arsenic, and German silver is a mixture of nickel, zinc, and copper. ”

“ The increased consumption of copper is perfectly explained by our knowledge that the last decade has been a period of great electrification and of great expansion in the use of the telephone. Moreover, the automobile manufacturing industry has become a great consumer of copper, about 15 per cent of the consumption in 1922 having been for that purpose. The increased consumption of zinc is explained partially in the same way, for zinc as a constituent of brass is used extensively in connection with copper. ”

“ Cobalt pyrites (linnæite) .
Nickel ores are used for extraction of the metal, which is used as a substitute for silver. The name is derived from the German, kupfernickel, or false copper. It was discovered in 1751.
Copper, again, forms a number of minerals, and the chief is the red oxide of the metal, called cuprite. It crystallizes in the cubic system. Its colour is red, and tinges a flame green. Cuprite yields excellent copper, and is found in Cornwall, and in many places on the continent. The black oxide is rarely found. ”

“ Here are also two very rare and curious specimens of yellow and grey sulphuret of copper, in forms resembling a cube, the latter being pseudomorphous.
The Royal Geological Society at Penzance possessed many valuable and rare specimens; among the earthy species may be enumerated, calcedony, sodalite, haiiyne, petalite, colophonite, vesuvian, &c. In the metallic branch, is carbonate of lead, specular iron, arseniate of iron, the oxide, carbonate, arseniate and phosphate of copper, native gold, found in the Cornish Tin Stream Works ”

“ Now artificial copperose, and such as we commonly use, is a rough and acrimonious kind of salt drawn out of ferreous and eruginous earths, partaking chiefly of Iron and Copper; the blew of Copper, the green most of Iron: Nor is it unusual to dissolve fragments of Iron in the liquor thereof, for advantage in the concretion. I say, a terrestrious or astringent humidity; for without this there will ensue no tincture; for Copperose in a decoction of Lettuce or Mallows affords no black, which with an astringent mixture it will do, though it be made up with oyl, as in printing and painting Ink. ”

“ Now, we know that copper is found in the mines in a state of such comparative purity as to require very little smelting for the purpose of being brought into a state fit for use, while, on the other hand, iron in its rough state looks more like a stone than a metal, and, moreover, before it can be worked at all, must be subjected to a difficult process of smelting by means of a very powerful fire. If we look at the question only on this side, we are forced to conclude, that copper must have been found and employed before iron. ”

“ Money is made of copper, too.
Tut. It is; for it takes an impression in coining very well, and its value is a proper proportion below silver, for a price for the cheapest commodities. In some poor countries they have little other than copper coin. Another great use of copper is as an ingredient in mixed metals, such as bell-metal, cannon-metal, and particularly brass.
Har. But brass is yellow.
Tut. True; it is converted to that colour by means of another metallic substance, named zinc or spelter, the natural colour of which is white. A kind of brown stone called calamine is an ore of zinc. ”

“ The fundamental principle consists in getting the ore into a solution, from which the metal can be precipitated. The ores of any economic importance contain the copper either as oxide, carbonate, sulphate or sulphide. These compounds are got into solution either as chlorides or sulphates, and from either of these salts the metal can be readily obtained. Ores in which the copper is present as oxide or carbonate are soluble in sulphuric or hydrochloric acids, ferrous chloride, ferric sulphate, ammoniacal compounds and sodium thiosulphate. ”

“ Copper has a brilliant yellowish-red colour, a nauseous, styptic taste, and emits a disagreeable odour when rubbed; is very malleable and ductile; unchanged in dry air; in damp air it soon becomes covered with a greenish rust (carbonate of copper) ; slightly soluble in dilute sulphuric and hydrochloric acid; freely soluble in boiling oil of vitriol (sulphurous anhydride being evolved) ; dilute nitric acid dissolves it readily with copious evolution of nitric oxide; heated to redness in the air, it rapidly becomes covered with a black scale (oxide) ; it fuses at a full red heat ”

“ Veins of copper are also frequently discovered in cliffs that are left bare by the sea, but the most certain sign of a rich ore is an earthy ocherous stone, called Gossan, of a ruddy colour, and crumbles like the rust of iron. Another sign of the presence of copper is, when the ground is inclinable to an easy free working blue Killas, intermixed with white clay. ”

“ Sometimes native copper, and carbonate of copper, are also present in the same specimen. In some instances, a partial decomposition has taken place, converting its green color into greenish-white, or perfect white, and rendering it so soft as to be cut with a knife. Sometimes the grains or masses of native copper are interspersed among the prehnite, and slender threads of this metal occasionally pass through the aggregated mass of greenstone, prehnite, &c., so that, on breaking it, the fragments are still held together by these metallic fibres. ”

“ There is a triple acetate of copper and lime, which resembles distilled verdigris in colour. It was manufactured pretty extensively in Scotland some years ago, and fetched a high price, till I published an analysis of it in the Edinburgh Philosophical Journal. It is much inferior, for all uses in the arts, to the proper binacetate.
VERDITER, or BLUE VERDITER. This is a precipitate of oxide of copper with lime, made by adding that earth, in its purest state, to the solution of nitrate of copper, obtained in quantities by the refiners, in parting gold and silver from copper by nitric acid. ”

“ Dissolve crystals of nitrate of copper in spirits of wine. Light the solution, and it will burn with a beautiful emerald green flame. Pieces of sponge soaked in this spirit, lighted and suspended by fine wires over the stage, produces the lambent green flames now so common in incantation scenes; strips of flannel saturated with it, and applied round copper swords, tridents, &c., produce, when lighted, the flaming swords and fire forks brandished by the demons in such scenes; indeed, the chief consumption of nitrate of copper is for these purposes. ”

“ The Fusion of Ores in Reverberatory and Cupola Furnaces.—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. ”

“ The uses of copper are numerous and important. When rolled into sheets, betwixt large iron cylinders, it is employed for the covering of houses, sheathing the bottoms of ships, and other purposes. As a covering for houses, copper is lighter than slate, but whether it be more durable has not been yet ascertained. The coppering of ships tends to facilitate their progress through the water, by presenting a smoother surface than that of wood, and not permitting shell animals to fasten to it as they do to wood. ”

“ Best Select Copper.—For the production of copper alloys, such as best brass, etc., it is essential that the copper should be pure. The impurities which are present in ordinary tough copper, and which may be valuable for imparting strength to the material, have a very harmful effect when present in alloys. In the older Welsh process of manufacturing copper, a special method was employed for obtaining metal free from these impurities, especially arsenic and antimony. ”

“ It is then, in his opinion, the solution of the metal—the wear of its surface, by keeping it smooth, which prevents the adhesion of foreign matter. Whenever the copper is unequally worn, deposits will, without doubt, rest in the rough parts, or depressions in the metal, and afford a soil or bed in which sea-weeds can fix their roots, and to which zoophytes and shell-fish can adhere; but there is another cause of foulness on the protected sheathing, arising from the deposit of earthy matter upon the copper, in consequence of its electro-negative condition. ”

“ Sulphuret of Copper; Kupferglanz. Of a steel gray metallic aspect; crystallizes in rhomboids; specific gravity 5·69; somewhat sectile, yet brittle; fusible with intumescence at the blowpipe, and yields a copper bead with soda; soluble in nitric acid; becomes blue with ammonia, but lets fall scarcely any oxide of iron. Its constituents are, sulphur 19; copper 79·5; iron 0·75; silica 1·00. It occurs in small quantities in Cornwall, &c.
The chemical preparations of copper which constitute distinct manufactures are, Blue or Roman vitriol; for which see Sulphate of Copper ”