Gerardo Alvear

• Doctor of Engineering
• President at Canadian Engineering Associates

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...

With the gradual decrease in the grade of copper ores being processed, copper concentrates have become more complex with higher impurity and gangue content. This trend has had a detrimental effect on smelters as they have to increase throughput to maintain copper metal production, while increasing operating costs due to processing the increased amo...

An optical probe for burner monitoring in copper flash smelting, first developed at the University of Concepcion, is being industrially tested in a collaboration between Kingston Process Metallurgy, Aurubis AG, and Queen's University. The sensor uses fibre-optics and optical emission spectroscopy to analyze the light emitted from combusting particl...

A drop tower and methodology were developed to study the impact of mineralogy on the flash combustion behaviour of copper concentrates. Reaction shaft conditions of a flash furnace were simulated using a drop tower reactor and different molar ratios of oxygen gas to sulphur in the feed. Five feeds were tested in the drop tower including pure minera...

The toxicity of arsenic is well known and documented; however, the presence of arsenic in copper electrorefining anodes and electrolytes is critically necessary to produce high-quality cathode. Arsenic as well as antimony and bismuth concentrations vary relative to their concentration in the anode copper received from the smelter. The behaviour and...

The ability to efficiently remove impurities contained in concentrates is a key point to consider when selecting copper smelting technology for new plants or modernisation projects. Volatilisation of impurities such As and Sb should occur as early as possible in the process, and preferably in the smelting furnace, so that they do not impact on down...

Southern Peru Copper Corporation (SPCC) are currently modernizing the Ilo copper smelter. A single ISASMELT furnace will start smelting 1,200,000 tonnes per year of concentrate during the second half of 2006. The existing Peirce Smith converters are being upgraded for converting the matte to blister copper and a new acid plant and oxygen plant are...

The thermodynamics of the Cu-Be-C-O system was studied in wide ranges of temperature and alloy composition, considering the importance of the minimization of Be2C and BeO formation in Cu-Be alloy production. The equilibrium relation of molten Cu-Be-C-O system was determined by conducting the following experiments: the solubility measurements of ber...

Intensive smelting of copper concentrate in Teniente Converter (CT) leads to the production of high grade matte and highly oxidized slag. Smelting slag is processed in Teniente vascular slag cleaning furnace. The slag composition and forms of copper affect the slag cleaning process and final copper content. Converting of high grade matte in Pierce-...

Considering the application of sodium carbonate slag to the elimination of Ni and Zn from molten copper, thermodynamic properties of NaO0.5–CO2–XO slag (X: Ni or Zn) and Cu–Zn–O melt have been investigated by conducting the following measurements.(1) Solubilities of NiO(s) and ZnO(s) into sodium carbonate melts at 1323 to 1523 K under various parti...

Thermodynamic properties of NaO0.5–CO2–XOv⁄2 slag (X: P or Si, v: valence of X) have been investigated by conducting the following measurements:(1) Solubility measurements of Na3PO4 (s) into sodium carbonate melts at 1423 to 1523 K under various partial pressures of CO2 and oxygen.(2) Activity measurements of NaO0.5 under various partial pressures...

In order to estimate the distribution ratios of Te and Se between sodium carbonate-based slag and molten copper, the following measurements have been conducted on the thermodynamic properties of the slags containing Te- or Se-oxide at 1423 to 1523 K.(1) Electrochemical measurements of activity of NaO0.5 in NaO0.5–CO2–XO2 slag (X: Te or Se) under va...