1. Ferrous metal
Ferrous metal mainly refers to iron and its alloys, such as steel, pig iron, iron alloys and cast iron. It is also called “black metal”.
The names “ferrous metal” and “non-ferrous metal” can often lead to misunderstandings, as people may assume that ferrous metal is always black.
However, there are actually three types of ferrous metals: iron, manganese, and chromium, none of which are actually black.
Pure iron is silvery white, chromium is silvery white, and manganese is grayish white.
Because the surface of iron often rusts, it is covered with a mixture of black ferric oxide and brown iron oxide, which has a black appearance. This is why people call it “ferrous metal”.
The term “ferrous metallurgy industry” mainly refers to the steel industry because the most common steel alloys are manganese steel and chromium steel, which is why people also consider manganese and chromium as “ferrous metals”.
In addition to iron, manganese and chromium, all other metals are considered non-ferrous metals.
2. Non-ferrous metal
Non-ferrous metals, also known as colored metals in the narrow sense, refer to all metals except iron, manganese and chromium. In a broad sense, colored metals also include colored alloys.
Non-ferrous alloys are alloys composed of a colored metal as the matrix (generally more than 50%) and one or more other elements.
Colored metals generally refer to all metals except iron (sometimes also manganese and chromium) and iron-based alloys.
Non-ferrous metals can be divided into heavy metals (such as copper, lead, zinc), light metals (such as aluminum, magnesium), precious metals (such as gold, silver, platinum) and rare metals (such as tungsten, molybdenum, germanium , lithium, lanthanum, uranium), which include a total of 64 types: aluminum, magnesium, potassium, sodium, calcium, strontium, barium, copper, lead, zinc, tin, cobalt, nickel, antimony, mercury, cadmium, bismuth, gold, silver, platinum, ruthenium, rhodium, palladium, osmium, iridium, beryllium, lithium, rubidium, cesium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, tungsten, molybdenum, gallium, indium, thallium, germanium, rhenium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium and thorium.
The strength and hardness of non-ferrous alloys are generally higher than those of pure metals.
They also have higher electrical resistance and lower temperature coefficient of resistance, and have good comprehensive mechanical properties.
Common non-ferrous alloys include aluminum alloys, copper alloys, magnesium alloys, nickel alloys, tin alloys, tantalum alloys, titanium alloys, zinc alloys, molybdenum alloys and zirconium alloys.
In practical applications, colored metals are generally classified into five categories:
- Light metals: metals with a density of less than 4,500 kilograms per cubic meter (0.53 ~ 4.5g/cm3), such as aluminum, magnesium, potassium, sodium, calcium, strontium, barium, etc.
- Heavy metals: metals with a density greater than 4,500 kilograms per cubic meter (4.5g/cm3), such as copper, nickel, cobalt, lead, zinc, tin, antimony, bismuth, cadmium, mercury, etc.
- Precious metals: metals with a high price compared to commonly used metals, with low crustal abundance, difficult purification and stable chemical properties, such as gold, silver and platinum group metals.
- Semimetals: materials with properties between metals and non-metals, such as silicon, selenium, tellurium, arsenic, boron, etc.
- Rare metals: including rare light metals such as lithium, rubidium, cesium, etc.; rare refractory metals such as titanium, zirconium, molybdenum, tungsten, etc.; dispersed rare metals such as gallium, indium, germanium, etc.; rare earth metals such as scandium, yttrium and the lanthanide series; and radioactive metals such as radium, francium, polonium, uranium and thorium.
3. Base metals
The term typically refers to a group of metals that are abundant and relatively cheap in the Earth's crust, such as iron, aluminum, copper, zinc, etc.
4. Rare metals
Rare metals are metals with low abundance and scattered distribution in the Earth's crust, or metals that are difficult to extract from raw materials, such as lithium, beryllium, titanium, vanadium, germanium, niobium, molybdenum, cesium, lanthanum, tungsten, radium, and others.
They can be divided into different categories based on their physical and chemical properties as well as their production methods:
- (1) Rare light metals such as beryllium, lithium, rubidium, cesium and others;
- (2) Rare precious metals such as platinum, iridium, osmium and others;
- (3) Dispersed rare metals such as gallium, germanium, indium, thallium and others;
- (4) Rare earth metals such as scandium, yttrium, lanthanum, cerium, neodymium and others;
- (5) Refractory rare metals such as titanium, zirconium, tantalum, vanadium, niobium and others;
- (6) Radioactive rare metals such as polonium, radium, actinium, uranium, plutonium and others.
Rare metals are mainly used to produce special steels, superhard alloys and high temperature resistant alloys, and are widely used in industries such as electrical, chemical, ceramics, atomic energy and rocket technology.
The names of rare metals have a certain relativity, and as people's research on rare metals expands, new sources and extraction methods are discovered, and their scope of application expands, the boundary between rare metals and other metals will gradually disappear .
Some rare metals are more abundant in the Earth's crust than copper, mercury, cadmium, and other metals.
Some rare metals are similar in physical and chemical properties and are not easily separated into single metals. In the past, they were rarely produced and used, hence the name rare metals.
The term “rare elements” existed in the 19th century, and in the 1920s it was renamed “rare metals.” The development of rare metals is relatively late, which is why they are sometimes called “new metals”.
Since the Second World War, with the development of new technologies and increased demand, research and application of rare metals have developed rapidly and new metallurgical processes continue to emerge, leading to an increase in their production.
Rare metals are no longer rare. The metals included in rare metals are also changing.
For example, titanium is increasingly used in modern technology and its production has increased, which is why it is sometimes classified as a light metal.
5. Light metal
Metals with a density of less than 5,000 kg/m 3 are called light metals, also known as light non-ferrous metals. There are seven metals in total, including aluminum (Al), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), potassium (K), and sodium (Na).
Rare metals with equally low density, such as beryllium, lithium, rubidium and cesium, are generally classified as rare light metals.
Calcium, strontium, magnesium and barium in light metals are collectively known as alkaline earth metals, while potassium and sodium are alkali metals.
Alkaline earth metals refer to the heaviest elements in group II A of the periodic table, while alkali metals refer to all elements in group IA, including lithium, rubidium, cesium, and francium, as well as potassium and sodium.
Aluminum, magnesium and their alloys have excellent physical and chemical properties and are important commonly used non-ferrous metals.
The alkaline earth metals calcium, strontium, barium and alkali metals sodium and potassium are generally used in the form of compounds in the chemical and other industries.
Furthermore, light metals have active chemical properties and are strong reducing agents, important in metallurgical industries.
6. Heavy metals
Heavy metals refer to metals with a density greater than 4.5 g/cm 3 including gold, silver, copper, iron, mercury, lead, cadmium and so on.
The accumulation of heavy metals in the human body, to a certain extent, can cause chronic poisoning.
In terms of environmental pollution, heavy metals mainly refer to biotoxic heavy elements such as mercury, cadmium, lead, chromium and arsenic-like metals.
Heavy metals are very difficult to be biodegraded, but they can be enriched thousands of times in the food chain by biomagnification and finally enter the human body.
Heavy metals in the human body can interact strongly with proteins and enzymes, causing them to lose their activity, and can also accumulate in certain organs of the human body, causing chronic poisoning.
7. Precious metal
Precious metals mainly refer to eight metallic elements: gold, silver and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium and platinum).
These metals mostly have beautiful colors and strong chemical stability, and generally do not react easily with other chemicals under normal conditions.
The cost of this metal is higher compared to other common metals and its availability in the Earth's crust is low.
This scarcity is also reflected in the Clarke value, which indicates the average concentration of chemical elements in the Earth's crust.
Purifying this metal is a challenging task, similar to refining gold, silver and platinum group metals.
8. Amphoteric elements
Amphoteric elements, also known as metalloid elements or semimetallic elements, are elements that exhibit some chemical properties of metals and nonmetals, such as boron, silicon, germanium, arsenic, antimony, selenium, and tellurium.
Its oxides and hydroxides are often amphoteric. Although they generally appear to have metallic properties, their chemical properties exhibit characteristics of both metals and nonmetals.
Its oxides are amphoteric, meaning they dissolve in both acids and bases.
Metalloids have a relatively large number of empty electron orbitals in their electronic structure, making them highly reactive and easily capable of forming organometallic compounds with organic molecules.
9. Rare metals
Rare metals are metals with relatively low abundance and scattered distribution in the Earth's crust, or metals that are difficult to extract from raw materials, such as lithium, beryllium, titanium, vanadium, germanium, niobium, molybdenum, cesium, lanthanum, tungsten and radium.
They can be classified according to their physical and chemical properties and production methods:
- (1) rare light metals such as beryllium, lithium, rubidium and cesium;
- (2) rare noble metals such as platinum, iridium and osmium;
- (3) dispersed rare metals such as gallium, germanium, indium and thallium;
- (4) rare earth metals such as scandium, yttrium, lanthanum, cerium and neodymium;
- (5) refractory rare metals such as titanium, zirconium, tantalum, vanadium and niobium;
- (6) radioactive rare metals such as polonium, radium, actinium, uranium and plutonium.
Rare metals are mainly used to make special steel, superhard alloys and high temperature resistant alloys in the electrical, chemical, ceramics, nuclear and rocket industries.
The names of rare metals are relative, and with extensive research into rare metals, the discovery of new sources and new refining methods, and the expansion of their range of applications, the boundaries between rare metals and other metals will gradually disappear as that some rare metals have greater abundance in the Earth's crust than copper, mercury, cadmium and other metals.
Some rare metals have similar physical and chemical properties and are not easily separated into individual metals.
In the past, they were rarely produced and used, hence the name “rare metals”.
The term “rare elements” was coined in the 19th century and in the 1920s was renamed “rare metals”.
The development of rare metals began relatively late, which is why they are also sometimes called “new metals”.
Since the Second World War, with the development of new technologies and increasing demand, the research and application of rare metals have developed rapidly, and new metallurgical processes have emerged, and the production of these metals has gradually increased.
Rare metals are no longer rare. The metals included in rare metals are also changing.
For example, titanium is increasingly used in modern technology, with production increasing, so it is sometimes classified as a lightweight metal.
Metal List Table
| Non-ferrous metals | copper, aluminum, lead, zinc, tin, nickel, magnesium, antimony, cobalt, mercury |
| ferrous metal | iron, manganese and chromium |
| Noble metal | gold, silver, platinum, palladium, ruthenium, rhodium, iridium, osmium |
| Light non-ferrous metal | aluminum, magnesium, sodium, potassium, calcium, strontium, barium |
| Heavy non-ferrous metal | copper, nickel, lead, zinc, cobalt, tin, antimony, mercury, cadmium, bismuth |
| Rare refractory metal | zirconium, molybdenum, vanadium, hafnium |
| Rare light metal | lithium, rubidium, beryllium, cesium, titanium |
| Scattered metal | gallium, indium, thallium, germanium |
| Scattered radioactive metal | radium, uranium, plutonium, francium, polonium, thorium |
| Rare earth metal | lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium |
| Semi-metallic | silicon, selenium, tellurium, arsenic and boron |
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