In 1916 there were active in the United States 13 refineries, nine of which employed the electrolytic method and five the furnace process on Lake Superior copper—one employing both methods. Their combined output for the year was 2,259,387,315 pounds, of which 1,950,255,629 pounds were electrolytic; 269,794,531 pounds were Lalce, and 39,337,155 pounds were casting and pig copper. Of the total refined product about 370,000,000 pounds were of foreign origin. In addition to this primary copper, the refineries handled secondary copper, producing from this source 78,585,296 pounds of electrolytic and 25,8313,511 pounds of casting copper. A part of this also was foreign. Besides this output of metal the refinenes also produced 55,622,345 pounds of blue vitriol, eqtuvalent to 14,043,315 pounds of metallic copper.
Secondary Copper is the name given to the copper recovered by smelters and refineries from scrap metals, sweepings, skinunings and dross, as distinguished from the primary copper denved directly from ores. The production of secondary copper in the United States in 1916 was . unprecedented, very large quantities of scrap from rolling mills and munition works finding their way to the secondary smelters. The record for the year shows a total of 140, 000 short tons of copper and copper in alloys (exclusive of brass), and 300,000 short tons oi brass containing about 70 per cent of copper, or about 210,000 tons-- a grand total of 350,003 tons, valued at $196,320,000.
Commercial . Copper.—In the American markets copper appears in three grades: elec trolytic, Lake and casting copper. Both electro lytic and Lalce grades test at least 99.8 pure. Electrolytic copper has a slightly higher degree of conductivity than Lake copper and greater endurance in bending and twisting tests, and is therefore preferred for electrical work. Cast ing copper is a fire-refined blister copper, testing sometimes as low as 98.5 per cent pure. It is unsuitable for electrical purposes or for making brass wire and sheet brass, but is available for malcing. copper or brass castings. The principal forms in which copper is marketed are ingots about 3 by 3 by 9 inches, weighing about 17 pounds; ingot-bars, about 3 by 3 by 27 inches, weighing about 50 pounds; wire-bars, about 31/2 by 31/2 by 33 and up to 60 inches, and weighing from 85 to 250 pounds; and cakes, in round or square forms, ranging in diameter from 8 to 39 inches, and 14 by 17 inches up to 42 inches square, and from 154 to 8 inches iu thickness. About one-third of the entire copper product of the country is used in making wire and elec trical supplies and one-fourth in making brass.
Production.— The world's smelter produc tion of • • •er for the year 1916 amounted to 3,106,995,• • pounds (estimated in part), an increase of more than 31 per cent over the pro duction of 1915, and almost exactly double the production of 1906. Of the grand total, the
United States smelters produced 1,927,850,548 pounds (62 per cent) ; Japan, 179,189 pounds (5.8 per cent) Chile, 157,474,578 pounds (5.1 per cent) ; Canada, 119,770,814 pounds (3.8 per cent) ; Mexico, 111,625,577 pounds (3.6 per cent) ; Spain and Po'rtugal, 110,230,000 pounds (3.6 per cent).
In the United States the mine production in 1916 was 57,863,365 tons of oapper ore, contain ing 2,005,875,312 pounds of metallic copper — an average of nearly 35 pounds per ton of ore Not all of this was recovered (in 1916) by the smelters, and this accounts for the variance with the figures given above for the United States under the world's production. In 1,011 mines copper was the principal product, and these mines produced a total of 1,977,724,7/34 pounds. In 837 other mines copper was recov ered as a by-product to the amount of 28,150,528 pounds.
Among the States, Arizona maintained first rank with the unprecedented output of 721, 833,169 pounds, more than 36 per cent of the output of the whole country, and an increase of 60 per cent over her record yield of 1915. Montana held second rank, with 352,928,373 pounds. Michigan was third with 273,692,525 pounds; Utah fourth, with 240,275,222 pounds; Alaska fifth, with 119,854,839 pounds, and Ne vada sixth, with 105,116,813 pounds. These five States with Alaska produced 93 per cent of the total copper output of the United States in 1916. The price of copper for the year aver aged 24.58 cents per pound — as compared with 17.50 cents in 1915. The total value of the country's production was $474,283,000.
Imports and In 1916 the United States imported a total of 462,335,980 pounds of copper, of which 268,927,315 pounds was in unrefined blocks, bars and pigs; 9,451,388 pounds in clippings and old metal and 8,411,2.30 pounds in refined plates, bars and rods. The remainder was the calculated copper content of ores (124, 878,905 pounds), concentrates (32,753,874 pounds), and matte and regulus (17,155,075 pounds), brought in to be smelted and refined. These importations came chiefly from Chile (121,342,981 pounds), Mexico (95,916,592 pounds), Canada (91,110,410 pounds), and Peru (77,672,763 pounds). The exports amounted to 789,791,254 pounds, valued at $231,915,832. Of the whole, 336,829,464 pounds went to France,• 184,564,740 pounds to the United Kingdom, and 113,764,478 pounds to Italy.
Grennawalt, W. E., 'The Hydrometallurgy of Comer' (New York 1912) ; Heath, G. L., 'The Analysis of Copper and Its Ores and (London 1916) ; Hofman, H. O., of Copper) (New York 1914) ; Levy, D. M., 'Modern Copper Smelting) 1912); Peters, E. D., Jr., 'Practice of Smelting) (New York 1911) ; Wiard, E. ., 'Theory and Practice of Ore (New York 1915).