Chapter 21 - Metallurgy and the Chemistry of Metals

Minerals provide the majority of metals.
A mineral is a naturally occurring substance that can have a wide variety of chemical compositions. * Ore is a mineral deposit that is concentrated enough to allow for the economic recovery of the desired metal.
Aluminum, iron, calcium, magnesium, sodium, potassium, titanium and manganese are the most abundant metals that exist in Earth crust as minerals.
Seawater has many metal ions, including Na+, Mg2+ and Ca2+, which are rich. * Moreover, vast areas of the ocean floor are covered with manganese nodules, mainly made of manganese and chemically combined iron, nickel, copper, and cobalt.

The science and technology of separating metals from their ores and creating alloys is known as metallurgy. * A solid solution of two or more metals, or a metal or metals with one or more nonmetals, is known as an alloy.
Magnets have a strong attraction to ferromagnetic metals. * A powerful electromagnet can be used to remove the mineral magnetite (Fe3O4) from the gangue. * Another ferromagnetic metal is cobalt.
Mercury may combine with a variety of metals to generate amalgams. * A mercury amalgam is a mixture of mercury and one or more additional metals.
Pyrometallurgy, or procedures carried out at high temperatures, is now used in the majority of key metallurgical processes. * Chemical or electrolytic methods can be used to reduce the size of these procedures.

Metallic bonding is based on band theory, which asserts that delocalized electrons can easily flow through "bands" created by overlapping molecular orbitals.
Several elements are semiconductors, which means that they are generally not conductors but can conduct electricity at high temperatures or when mixed with a little number of other elements.
Because they give conduction electrons, these impurities are known as donor impurities. * N-type semiconductors are solids that include donor impurities, where n stands for negative.
P-type semiconductors are those that contain acceptor impurities, with the letter p standing for positive. * Acceptor impurities are those that are lacking in electrons.

Metals are shiny, solid at normal temperature, have good heat, the characteristics conductors, malleable, and ductile.
The metallic nature of metals increases from right to right through a period and from top to bottom within a group in just the opposite directions.
Metals tend to form cations and almost always have positive numbers of oxidation in their compounds, because they generally are lowly electronegativity. * However, beryllium and magnesium form covalent compounds in Group 2A and in Group 3A metals.

The melting temperatures of alkali metals are low, and they are soft enough to be cut with a knife. * These metals all have a crystal structure that is body-centered and has a low packing efficiency.
Alkali metals are found in combination with halide, sulfate, carbonate, and silicate ions and are never found in their elemental form.
The nature of sodium and potassium is about equal. * In silicate minerals like albite (NaAlSi3O8) and orthoclasses they occur (KAlSi3O8).
Silicate minerals are slowly decomposed by wind and rain and are converted to more soluble compounds over a long period.
These compounds are finally leached from the ground and carried to the sea by rain. * However, if we look at the marine water composition, the sodium/potassium concentration ratio is around 28 to 1.

Alkali Metals

It's mostly used as an alloying agent for metals like aluminum and copper, as well as to make beryllium metal from its compounds.
Calcium is a necessary component of all living things. * The calcium ion is present in a complex phosphate salt, hydroxyapatite, Ca5(PO4)3OH, which is the main component of bones and teeth.
Magnesium oxide react very slowly with water to magnesium hydroxide in a White Solid Suspension called Magnesium Milk.

In the Earth's crust, aluminum is the most abundant metal and the third most abundant element. * The elemental form does not exist in nature; bauxite is the primary resource.
Bauxite, which is commonly polluted with silica (SiO2), iron oxides, and titanium(IV) oxide, is used to make aluminum.
The Hall process reduces anhydrous aluminum oxide, or corundum, to aluminum.
The exothermic enthalpy of production of aluminum oxide is quite high (Hf ° = 1670 kJ/mol). * Aluminum is suitable for use in solid propellants for rockets, such as those used in some space shuttles, because of its characteristic.