Industry Description

The nonferrous metals industry encompasses establishments that engage in the following: primary and secondary smelting and refining of nonferrous metal from ore or scrap; rolling, drawing, and alloying; and the manufacturing and casting of basic metal products such as nails, spikes, wire, and cable. Primary smelting and refining produces metals directly from ores, and secondary refining and smelting produces metals from scrap and process waste. Scrap is bits and pieces of metal parts, bars, turnings, sheets, and wire that are off-specification or worn out but capable of being recycled.1 The industry does not include the mining and beneficiation of metal ores; rolling, drawing, or extruding metals; or scrap metal collection and preliminary grading.2

Two metal recovery technologies are generally used to produce refined metals. Pyrometallurgical technologies are processes that use heat to separate desired metals from other less or undesirable materials. These processes capitalize on the differences between constituent oxidation potential, melting point, vapor pressure, density, or miscibility when melted. Examples of pyrometallurgical processes include drying, calcining, roasting, sintering, retorting, and smelting. Hydrometallurgical technologies differ from pyrometallurgical processes in that the desired metals are separated from undesirables using techniques that capitalize on differences between constituent solubilities or electrochemical properties while in aqueous solutions. Examples of hydrometallurgical processes include leaching, chemical precipitation, electrolytic recovery, membrane separation, ion exchange, and solvent extraction.

During pyrometallic processing, an ore, after being concentrated by beneficiation (crushing, washing, and drying) is sintered, or combined by heat, with other materials such as baghouse dust and flux. The concentrate is then smelted, or melted, in a blast furnace in order to fuse the desired metals into impure molten bullion. This bullion then undergoes a third pyrometallic process to refine the metal to the desired level of purity. Each time the ore or bullion is heated, waste materials are created. Air emissions such as dust may be captured in a baghouse and are either disposed of or returned to the process depending upon the residual metal content. Sulfur is also captured, and when concentrations are above 4% it can be turned into sulfuric acid, a component of fertilizers. Depending upon the origin of the ore and its residual metals content, various metals such as gold and silver may also be produced as byproducts.

There are an estimated 800 plants in the U.S. involved in the primary or secondary recovery of nonferrous metals. These plants represent 61 subcategories. However, many of these subcate-gories are small, represented by only one or two plants, or do not discharge any wastewater. This chapter focuses on 296 facilities that produce the major nonferrous metals [aluminum, columbium (niobium), tantalum, copper, lead, silver, tungsten, and zinc]. The volume of wastewater discharged in this industry varies from 0 to 540 m3/T (0 to 160,000 gal/t) of metal produced.1,3 The global size of the industry is reflected in Table 3.1 (reported in 1000 USD) for the top 20 export countries for nonferrous base metal waste and scrap.4 Here T = metric ton = 1000 kg = 2204.6 lb, t = 2000 lb.

Nonferrous metal facilities are distributed throughout the U.S. Most sites are located near ore production facilities, near adequate transportation facilities, or near adequate power supplies.

Table 3.2 presents an industry summary for the nonferrous metals industry indicating the number of subcategories and the number and type of dischargers. Table 3.3 presents best practicable technology (BPT) limitations that have been promulgated and reported in the Federal Register.3,5

Production operations are subject to a number of regulations, including those imposed by the Resource Conservation and Recovery Act (RCRA),6,7 the Clean Water Act (CWA),8 and the Clean Air Act (CAA).9 A number of RCRA-listed hazardous wastes are produced during primary refining operations that require the heating of ores to remove impurities. Specific pretreatment standards under the CWA apply to the processes associated with copper and aluminum. Lastly, large amounts

TABLE 3.1

Global Size of the Nonferrous Metal Industry (1GGG USD)

TABLE 3.1

2GG1

2GG2

2GG3

2GG4

2GG5

U.S.

1,168,979

1,205,751

1,525,103

1,959,119

2,732,399

Germany

1,026,226

987,855

1,188,257

1,586,034

1,782,619

U.K.

539,568

578,023

693,718

967,331

1,256,697

France

514,214

539,964

562,873

899,418

1,124,048

Mozambique

586

297

1,022,005

Canada

547,290

500,397

502,896

689,104

851,403

Netherlands

278,752

312,556

426,390

616,114

799,880

Belgium

275,577

268,371

295,804

554,500

535,881

Japan

124,748

150,086

215,931

314,197

533,532

Mexico

240,521

202,321

258,524

383,034

501,177

Spain

371,858

407,224

438,838

337,198

499,065

Australia

167,667

210,146

260,276

309,567

378,943

Italy

111,081

109,916

127,044

293,584

367,374

Switzerland

157,352

153,179

175,809

256,276

317,029

Chile

93,607

103,244

121,045

186,278

245,939

Thailand

43,885

49,214

76,483

134,662

224,893

Poland

98,152

105,213

142,727

177,777

223,185

Singapore

138,611

147,928

145,768

194,402

219,283

Sweden

98,071

107,138

140,437

176,010

217,977

Korea, Republic

28,725

30,580

61,183

176,905

200,589

of sulfur are released during copper, lead, and zinc smelting operations, which are regulated under the CAA.

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