September/October 1997
A lustrous, bluish-white metallic element; insoluble in water, brittle at room temperature; Ductile, malleable, fairly conductive; second most common metal—after iron—in the human body.
Zinc has been in use since before Roman times as a component of brass, principally as an oxide rather than in metallic form. Metallic zinc was known in Europe, China, and India by about 1600, with the earliest extraction of zinc metal reportedly dating to 14th-century India. Zinc’s principal ore is the mineral sphalerite, and deposits usually contain more than one metal.
Today, zinc, along with its alloys and chemical compounds, ranks fourth in usage among industrial metals. Its principal applications include coatings for corrosion protection (galvanizing) and casting alloys (die casting). Zinc is also used as an alloying element in brass and bronze, as well as in chemicals such as oxides and wrought alloys such as rolled zinc. Its use in U.S. coinage has also increased. In 1982, for example, the U.S. Mint changed the composition of pennies from 95 percent copper and 5 percent zinc to 2.5 percent copper and 97.5 percent zinc.
Scrap Facts. Expressed as a percentage of total zinc consumption, domestic scrap usage ranks relatively low compared with most other nonferrous industrial metals—17 percent in 1996 compared with 44 percent for aluminum, 38 percent for copper, and 65 percent for lead. This is because many of zinc’s uses are dissipative and thus nonrecoverable. Brass scrap, for example, is usually remelted and recast as brass. Also, galvanized steel is predominantly melted as is, with the zinc coating vaporizing and ending up in mills’ furnace dust.
Drosses from galvanizing, skimmings, ashes, and die castings make up the bulk of feedstock for zinc recycling. Steelmaking dusts and zinc-coated steel scrap, however, remain rich sources of recoverable zinc, though their full potential has yet to be realized.
Pricing Info. Although zinc first appeared on the LME in 1914, the contract for special high-grade—or SHG—zinc didn’t become the globally recognized price reference for both refined metal and scrap until 1991, replacing producer list prices and another outdated zinc contract. European producers were the first to base their pricing on the LME, with the United States and Canada soon following suit. Today, domestic sellers typically quote the LME cash zinc price, plus a negotiated premium. Scrap zinc, such as galvanizing dross, is normally quoted as a percentage of the cash LME price. Other scrap items—such as die cast—are quoted in cents per pound.
—Robert J. Garino, ReMA director of commodities •
A lustrous, bluish-white metallic element; insoluble in water, brittle at room temperature; Ductile, malleable, fairly conductive; second most common metal—after iron—in the human body.