Melting copper production

Scra.p Copper. The energy required for copper production from scrap is appreciably less than that needed production from ores. If the scrap is of low grade and has to be smelted and refined, the energy consumption is about 45 GJ /1 (43 x 10 Btu/t) of copper (52). Scrap that only requires melting and casting uses about 5 GJ/t (4.7 X 10 Btu/t) of copper. 

Technology has defined societies and civilizations since the beginning of time. We use technology to describe different periods of time. When we refer to the Stone Age, for example, it is because early humans had only stones, bones, and sticks to make tools and weapons. In the Bronze Age, people had learned how to melt copper and pour it into molds, as well as to shape it in other ways. During the period described as the Iron Age, humans had discovered how to fashion iron ore into tools, weapons, and other products. As the name implies, the Industrial Age was the period of time when factories and manufacturing were growing rapidly. The Information Age is the age that we live in today. It is called the information age because information has become more valuable than manufactured products. 

During the electrolytic step of copper production an anode slime is obtained, containing the noble metals of the ore. They are extracted by a compHcated process. Raw silver is obtained by melting, and is used as a new anode material. In an electrolytic process with nitric acid as electrolyte silver dissolves from the anode while gold and platinum form a new anode sHme. Silver is precipitated from the electrolyte as silver chloride. This is melted with soda and saltpeter at 1000°C. The molten silver is cast into bars and remelted in vacuum to yield very pure, gas-free silver. 

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

The roaster product is then charged to the Dorn furnace where it is melted and the resulting metal is fire-refined to eliminate the arsenates, selenates, antimonates, teUurates, and residual copper. 

The output from brass mills in the United States is spHt nearly equally between copper and the alloys of copper. Copper and dilute copper alloy wrought products are melted and processed from electrically refined copper so as to maintain low impurity content. Copper alloys are commonly made from either refined copper plus elemental additions or from recycled alloy scrap. Copper alloys can be readily manufactured from remelted scrap while maintaining low levels of nonalloy impurities. A greater proportion of the copper alloys used as engineering materials are recycled than are other commercial materials. 

Electroforrning is the production or reproduction of articles by electro deposition upon a mandrel or mold that is subsequendy separated from the deposit. The separated electro deposit becomes the manufactured article. Of all the metals, copper and nickel are most widely used in electroforming. Mandrels are of two types permanent or expendable. Permanent mandrels are treated in a variety of ways to passivate the surface so that the deposit has very Httie or no adhesion to the mandrel, and separation is easily accompHshed without damaging the mandrel. Expendable mandrels are used where the shape of the electroform would prohibit removal of the mandrel without damage. Low melting alloys, metals that can be chemically dissolved without attack on the electroform, plastics that can be dissolved in solvents, ate typical examples. 

The melt is heated by passing a large elecuical cunent between two electrodes, one of which is tire metal rod to be refined, and the otlrer is the liquid metal pool standing in a water-cooled copper hearth, which collects the metal drops as tlrey fall tluough the molten electrolyte. This pool tlrerefore freezes at the bottom, forming the ingot. Under optimum chcumstances tire product billet takes the form of a cylindrical solid separated from the molten salt by... 

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