William Davenport

• University of Arizona

The pyrometallurgical production of copper from sulfide concentrates is a journey involving the gradual oxidation of copper concentrates in sequential steps. These steps are smelting, converting, and refining. The overall copper making process can be explained by using the copper–oxygen–sulfur predominance diagrams. This tool is a navigation chart...

About 95% of the copper currently produced in the United States has existed as cathode copper at some time during its processing. To make it useful, this copper must be melted, alloyed as needed, cast, and fabricated. Much of the fabrication process for copper and its alloys is beyond the scope of this book. However, melting and casting are often t...

Continuous copper making processes can be achieved in a single, double, or three stages. The selection of the process depends on the type of material to be processed and the aimed final product.

Sulfur is evolved by most copper extraction processes. The most common form of evolved sulfur is sulfur dioxide (SO2) gas from smelting and converting. It must be prevented from reaching the environment. Most smelters capture a large fraction of their SO2. It is almost always made into sulfuric acid, occasionally liquid SO2 or gypsum. This chapter...

Virtually all the molten copper produced by smelting/converting is subsequently electrorefined. It must, therefore, be suitable for casting into thin, strong, smooth anodes for interleaving with cathodes in electrorefining cells. This requires that the copper be fire refined to remove most of its sulfur and oxygen. Fire refining removes sulfur and...

Electrolytic refining is the principal method of mass-producing high purity (>99.97%) copper. The other is electrowinning. Copper from electrorefining, after melting and casting, contains less than 20 ppm impurities, plus oxygen, which is controlled at 0.018%–0.025%. Electrorefining entails electrochemically dissolving copper from impure copper ano...

Impure leach solutions containing relatively low concentrations of copper are processed to high copper concentration, pure electrowinning (EW) electrolytes by Solvent extraction (SX). It is a crucial step in producing high-purity electrowon copper from leached ores. The SX process consists of extracting Cu²⁺ from aqueous PLS into a copper-specific...

This chapter (a) describes the investment and production costs of producing copper metal from ore, (b) discusses how these costs are affected by such factors as ore grade, process route, and inflation and, (c) indicates where cost savings might be made in the future. The discussion centers on mine, concentrator, smelter, and refinery costs. Costs o...

Copper converting is the oxidation of molten Cu–Fe–S matte to form molten blister copper (99% Cu). It entails oxidizing Fe and S from the matte with oxygen-enriched air or air blast. The main raw materials for converting are matte, flux, oxygen, and additional cooling agents to manage heat generation and increase copper production. The main product...

The production of copper generates a number of byproduct and waste streams. In some cases, these streams contain valuable components that are profitable to recover. In other cases, treatment of these streams is needed to prevent the release of toxic or hazardous chemicals. The processing of byproduct streams is therefore a significant activity at c...

Copper is essential to economic and technological development, so substantial growth in its applications has continued in the 21st century, driven by the rapid industrialization of China and other emerging-market economies. This chapter discusses production and use of copper around the world. It gives production, use and price statistics, and ident...

This chapter explains how Cu²⁺ ions generated by leaching are reduced and electrowon as pure metallic copper in the form of cathodes. The electrowinning process entails (a) immersing metal cathodes and inert (but conductive) anodes into a purified electrolyte containing CuSO4 and H2SO4; (b) applying an electrical current from an external source, su...

About half the copper reaching the marketplace has been scrap at least once, so scrap recycle is of the utmost importance. This chapter describes scrap recycling in general, major sources and types of scrap, and physical beneficiation techniques for isolating copper from its coatings and other contaminants.

Metallic copper has been known to man since about 10,000 B.C. Although its use gradually increased over the years, it was only in the 20th century, with the global adoption of electricity, that copper usage really expanded. Copper is essential to economic and technological development, so substantial growth in its applications has continued in the...

Pyrometallurgical processing of copper concentrates to produce pyrorefined copper is based on the continuous management of the sulfur and oxygen potentials. The oxygen–sulfur potential management is done in sequential stages to control heat released from the chemical reactions and the overall copper recovery. This principle has been the corner ston...

Hydrometallurgical extraction accounts for about 20% of total primary copper production. Most of this is produced by heap leaching. Heap leaching consists of trickling H2SO4-containing lixiviant uniformly through flat-surfaced heaps of crushed ore, agglomerated, or run-of-mine ore. Heap leaching generates a pregnant leach solution (PLS) containing...

Flash smelting accounts for around half of all Cu matte smelting. It entails blowing oxygen, air, concentrate, flux, and recycle materials into a hearth furnace. The process is continuous. When extensive oxygen enrichment of the blast is practiced, it is nearly autothermal. It is perfectly matched to smelting fine particulate concentrates produced...

The main characteristic of bath smelting processes is the transfer of oxygen into molten phase required to produce copper matte. Oxygen can be transferred to the slag as in case of Top Submerged Lance processes, Vanyukov, and the SBF-Baijin process or to the molten bath as in case of the SKS-BBS, Noranda, El Teniente, and Side Blowing Furnace Jifen...

Pyrometallurgical production of molten copper generates two slags, smelting and converting. Smelting furnace slag typically contains 1%–2% Cu. Converter slag contains 4%–8% Cu. This chapter discusses the nature of copper in smelting and converting slags. It also describes strategies for minimizing the amount of copper lost from their disposal. The...

In the last 40 years, the copper industry has evolved to become more energy efficient, environmentally sustainable, and competitive. Pyrometallurgical production has also shifted to China and resources have become more complex. Recycling has also become more relevant as society has transformed its core to become a high intensity metal consuming one...

About one-third of the copper currently produced in the world is derived from secondary materials. Secondary material is recycled in numerous ways. New scrap is often recycled directly back to the melting furnace where it was produced in the first place. Old scrap and waste streams (and some new scrap) travel a more complex path. It can either be a...

Rare earths occur around the world but are mostly mined and extracted in China. Mining in other countries (e.g., Australia, India, and USA) is increasing—but slowly. Prices of all rare earths peaked in 2011. They have fallen ever since. This has had a discouraging effect on new mining projects. Rare earths have a myriad of uses. The major uses (ton...

Rare earths are the elements whose behaviors result from filling the 4f orbitals from lanthanum to lutetium. The 4f orbitals are partially filled yet they are buried below the 5s and 5p orbitals, which shield them from the local environment. The localized 4f orbitals are, therefore, not affected by the crystal field while the extended 5d orbitals a...

Rare earth ions are used widely in optical gain media. The most important applications are in (i) optical amplifiers for telecommunication networks, especially erbium-doped glass fiber amplifiers and (ii) solid state lasers. Erbium-doped fiber amplifiers are by far the most important amplifiers in the world's optical fiber communications system. Th...

This chapter describes production of pure, marketable individual rare earth compounds from Chapter 4's impure mixed rare earth carbonate precipitate feed. As applied to rare earths the production of pure individual rare earth compounds entail: (i) leaching Chapter 4's impure mixed rare earth precipitate; (ii) purifying the resultant solution from n...

In 2013, only 2% of rare earths in end-of-use products are recovered by recycling—this compared to 90% for iron and steel. The reasons for this low recovery are (i) the low concentrations of rare earths in many end-of-use products, e.g., catalysts, (ii) the presence of rare earths in difficult-to-decompose compounds, fir example, cerium zirconate i...

Luminescent materials are widely used in everyday life, e.g., for lighting (fluorescent lamps), displays (liquid crystal displays, plasma televisions), lasers (DVD players), and medical diagnoses (positron emission tomography). Rare earths are used extensively in these devices because of their intrinsic properties, which derive from their unpaired...

Rare earth elements occur mainly in bastnasite-monazite igneous ores, monazite beach sands, and rare earth cation adsorption clays. They are all mined by surface mining techniques. Bastnasite-monazite igneous ores are concentrated by froth flotation. Monazite beach sands are upgraded by gravity/electrostatic/magnetic waste rock removal techniques....

Phosphors represent about 9% of the rare earth global market. Ninety-seven percent of these phosphors are devoted to lighting and display applications. Rare earth elements are widely used in applications where light emission is a criterion of performance. This is especially the case in lighting devices and displays, such as fluorescent lamps (La, Y...

In 2014, ~ 90% of rare earth production originates in the mines of Inner Mongolia, China. High-purity (99.9 mass%) rare earth compounds (e.g., oxides) are produced from these ores by physical concentration, leaching, solution purification, solvent extraction separation, and individual rare earth compound precipitation. About 40% of all rare earth p...

The most powerful magnets are made by alloying Sm and Co as well as Nd and Fe. A complex oxygen-free powder metallurgy is needed to prepare samples. Magnetization is also a critical process. For cost and performance reasons the Nd/Fe/B magnets dominate the market. This is the fastest growing field in the Rare Earth industry. New generation of perma...

This chapter describes fused salt electrowinning of rare earth metals. The process entails (i) dissolving a rare earth compound (e.g., Nd2O3) in 1050 °C molten halide electrolyte, (ii) passing direct electric current through the electrolyte from a graphite anode to a tungsten cathode, and (iii) electrodepositing molten rare earth metal (e.g., neody...

Nickel-metal hydride batteries contain considerable rare earth metals, particularly La, Ce, Pr, and Nd. About 10% of rare earth production is used in this application. Charged Ni-MH batteries provide power by oxidizing the hydrogen that is in a charged battery's alloy electrode. The roles of the rare earths in this alloy are to store its hydrogen a...

Rare earth elements are used widely around the world. They are the greenest option for many technologies, for example, in automobiles. China dominates rare earth production. In 2014 it is mining/extracting 90+% of the world's rare earth supply. With one overwhelmingly dominant rare earth producer, the rare earth industry will be unstable till 2020...

Metallothermic reduction is the reaction of a metal reductant with a rare earth oxide or halide to produce rare earth metal. Important examples are (i) reduction of samarium oxide with lanthanum to produce samarium metal and (ii) reduction of gadolinium fluoride with calcium to produce gadolinium metal. The process is always operated in batch mode...

The most powerful magnets are the alloys Sm/Co and Nd/Fe/B. They are characterized by strong magnetic flux Br and high resistance to demagnetization also called coercitivity Hc. Quantity BH, the energy product, represents the figure of merit of the magnets. The NdFeB magnets are cheaper and more powerful. The performances depend on the temperature....

Rare earth metals are used in magnet alloys and nickel-metalhydride rechargeable battery electrode alloys. They are also used in ductile cast iron alloys, to precipitate carbon nodules, thereby improving alloy ductility. Cerium is particularly important in this application. Another important use is in magnesium alloys to improve (i) castability, (i...

An important use of rare earth catalyst is in automotive catalytic converters. In this service, it speeds up the conversion of unhealthful CO(g), CmHn(g), NOx(g) and soots in engine-out gas to innocuous CO2(g), H2O(g), and N2(g) in tailpipe exhaust gas. With platinum group metal/ceria-zirconia catalyst, conversion to innocuous tailpipe gas is nearl...

Polishing has two fundamental purposes: (i) surface smoothing and (ii) weight reduction. Surface smoothing is important in (i) glass sheet edge polishing and beveling, (ii) eyeglass and other precision lens polishing, (iii) glass memory disk polishing, (iv) silicon wafer polishing for integrated electronic circuits, and (v) fused silica photomasks,...

The main industrial minerals used up to now for rare earth production are bastnasite, monazite, xenotime and rare earth adsorption clays. Bastnasite, monazite and xenotime are all processed by caustic soda leaching or sulfuric acid roasting. For the time being, rare earth adsorption clays have been processed only in China with a quite different tec...

The production of nickel and cobalt from primary sources involves beneficiation, and hydrometallurgical and pyrometallurgical processing. Nickel is recovered from lateritic oxides either as ferronickel from saprolite ores or as an intermediate mixed sulfide or hydroxides from limonite ores. Sulfide ores are converted into matte. Intermediate produc...