Metallurgy Topics or Metal Technology +

(terms about the science and technology of metals and metal processing)

alkali metals
The first group of the Periodic Table of Elements, IA, including lithium, sodium, potassium; as well as, the lesser-known and rarer rubidiuim, cesium, and francium.

Alkali metals are not very electronegative, meaning they attract electrons very weakly.

All of the alkali metals can act as electrolytes in solution, meaning that they conduct electricity. Many of these elements are found in alkaline batteries.

Lithium in particular is found in many types of batteries and it is also an important component of several drugs used to treat mental illness.

alkaline earth metals
These are the second group on the left of the Periodic Table, IIA, which include beryllium, magnesium, calcium, strontium, barium, and radium.

When these elements are combined with oxygen or water, they form compounds with a basic pH.

Alkaline earth metals are not very electronegative. They have just two valence electrons, and will lose them to become positively charged ions or cations.

alloy, alloys
Alloys have been known since virtually the beginning of recorded history; a prehistoric age, in fact, is known as the Bronze Age, indicating the advent of human's ability to smelt bronze, an alloy of copper and tin.

Other well-known alloys include brass, an alloy of copper and zinc; and steel, an alloy of iron and carbon.

Alloys have been created by mixing metals with semi-metals like arsenic and antimony and with nonmetals like carbon and silicon.

Most alloys are developed for a specific physical characteristic; such as, malleability or strength.

A metal that is produced by the Hall process, an electrolytic reduction technique that was invented in 1886 by Charles M. Hall, an American scientist.

In this process, ore that contains the aluminum, most often bauxite, is first purified to form a substance called alumina, which contains both aluminum and oxygen.

The alumina is placed in a bath of melted cryolite, whose constituents include fluorine and iron; fluorspar, a compound of calcium and fluorine, is added to lower the melting point.

The elemental aluminum that is produced by the Hall process has many uses because of its light weight, tensile strength, and good conductivity of heat and electricity.

Most notably, all of the modern aircraft that are flown by the military services and airlines have aluminum as their primary structural material.

An alloy of mercury (Hg) and another metal or metals; for example, amalgams containing mercury and silver (Ag) are often used as dental fillings.
A heat treatment applied to metals.

Annealing is more often applied to the reduction of the hardness of a metal; however, annealing can also be done to change the microstructure of a metal or to achieve a specific set of physical or mechanical properties.

In the annealing process, the metal is first heated to a predetermined temperature and then it is allowed to cool to room temperature. It is often an important step in the production of specific metal types.

In the production of fine wires, there may be several intermediate annealing steps before the metal is drawn through fine openings to produce wirea with the desired properties.

creating alloys
Alloys are most often created during the molten stage of a metal, and the alloying element is usually added during the refinement process.

Steel is made by introducing carbon from the coke used in the refinement of iron ore.

Alloys are also divided into ferrous (iron based) and non-ferrous, in which the base is usually copper, aluminum, or titanium.

electrometallurgy, hydrometallurgy
Two techniques that are used in metallurgy, which is concerned with extracting metals from ores, refining them, purifying them, and preparing them for practical applications.

While some metals; such as, gold and silver can be found uncombined with other elements in nature, most metals occur as minerals; that is, in chemical combination with nonmetallic elements.

When the combination is such that the extraction of a metal from a mineral is economically attractive, the combination is called an ore. The technique of producing metals from ore is called "process metallurgy" or "extraction metallurgy".

extractive metallurgy, extraction metallurgy; process metallurgy, processing metallurgy
Metallurgy which is concerned with the extraction of metals from their ores, refining, and adapting them for use.

Metals are extracted from ores in three primary ways:

  1. Dry processes; such as, smelting, volatilization, or amalgamation; which is treatment with mercury.
  2. Wet processes, involving chemical reactions.
  3. Electrolytic processes, which work on the principle of eletcrolysis using electricity conducted by a solution or melt to effect chemical changes.
fabrication metallurgy (s) (noun), fabrication metallurgies (pl)
The processes by which raw metals are made into alloys and useful products: David's son works for a company that produces various products with fabrication metallurgies; such as, wires, cooking pots and pans, filing cabinets, metal shelves, tools, etc.
The science and technology of extracting and recovering metals chemically from ores by the use of aqueous or water solutions, as distinct from pyrometallurgy which consists of of smelting and other similar high-temperature operations.

The principles involved in hydrometallurgy are those of physical chemistry, inorganic chemistry, electrochemistry and analytical chemistry.

Hydrometallurgical processes are used commercially because hey are convenient to operate, the recovery of metals is high, and operating costs usually are low; and especially, because of the variety of quantitative chemical separations that can be made in aqueous solutions much more readily than is possible with the melts used in pyrometallurgical processes.

—Compiled from information located in the
Encyclopedia Britannica; William Benton, Publisher;
Chicago; 1968; pages 961 & 962.
metal air fuel, metal fuel cell, metal fuel technology
A fuel cell technology that uses metals; such as, zinc, aluminum, and magnesium in place of hydrogen to provide electrical power in order to overcome certain disadvantages that are associated with hydrogen as a fuel.
metal detector
Electronic device for detecting metal which is usually below the surface of the ground, developed from the wartime mine detector.

In the head of the metal detector is a coil, that is part of an electronic circuit.

The presence of metal causes the frequency of the signal in the circuit to change, setting up an audible note in the headphones worn by the user.

metal halide lamp
A type of high-intensity discharge (HID) lamp in which most of the light is produced by radiation of metal halide (chemical compound of a halogen) and mercury vapors in the arc tube, similar in construction and appearance to mercury vapor lamps.

The addition of metal halide gases results in higher light output, more lumens (unit of luminous flux) per watt, and better color rendition than from mercury gas alone.

metal hydride storage
A device that can store hydrogen by means of a metal carrier; considered a relatively safe and compact method of hydrogen storage.

The hydrogen can either be stored in the cavities of a grid of metal; such as, magnesium or titanium, or it can enter into an ionic bond with the metal.

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