Category Archives: Facts

Calcined Bauxite

Calcining, also called calcination, is an industrial process that uses very high temperatures, often between 1,400-1,800 degrees Fahrenheit (800-1,000 degrees Celsius) or higher, to change the physical and chemical properties of various solid materials, such as minerals, metals, and ore. The origin of the term comes from one of the oldest and most common calcining processes: turning limestone, also known as calcium carbonate, into lime, or calcium oxide. This process is commonly used to remove volatile substances in a material, to improve its electrical conductivity, or to remove water or certain impurities. The process is used in various industrial settings, for example in oil refineries, in some recycling plants, and it is also part of the pulping process when making kraft paper products. Processing facilities fired by oil or gas are commonly used to achieve the high temperatures needed for calcination, and these facilities are usually called furnaces, reactors, or kilns.
Originally, the word calcining was used to refer to processes that involved calcium, as when limestone is turned into lime. However, the term is also used to describe similar processes, using similar temperatures and equipment that do not involve calcium. For example, clay can undergo calcining, even though there is no calcium present in the material. Clay that’s been treated in this way is anhydrous, meaning it contains no water. This can be used as an abrasive or in different kinds of coatings.

Some recycling facilities use calcination to recycle metal waste products, like grindings, polishing mud, and slurries. It can also be used to turn petroleum coke, a byproduct from oil-distillation that contains a large amount of carbon, into a much purer form of carbon. This calcined petroleum coke can be used for various purposes, such as to make carbon anodes used when producing aluminum.

Various forms of aluminum hydroxide can also undergo calcining, by being heated to temperatures over 2,000 degrees Fahrenheit (1,100 degrees Celsius). This is done to remove the crystalline water from the material, turning it into an alumina, or aluminum oxide, that has other properties and uses than aluminum hydroxide. Calcined alumina is produced in various grades and for various purposes, for example for use in the manufacture of electrical and electronic products and to produce synthetic gems used for different types of lasers. The process is also used to remove the water in bauxite, producing calcined bauxite which can be used to make aluminum oxide.

Silicon-Calcium Cored Wires

Calcium Silicon alloy is widely used to improve the quality, castability and machinability of steel.
Calcium  is  a powerful  modifier of oxides  and sulfides.  It  transforms  alumina inclusions  into
complex Calcium aluminate compounds, improving the castability of the steel in a continuous
casting process.  Other benefits  include reduction in  deposits  of  solid inclusions  inside of the
tundish nozzles, preventing clogging.  Calcium also improves steel’s machinability, increasing
the life of cuting tools. This  product  has been developed for the Calcium  treatment  of  Al­kiled, restricted­Silicon­ content steels.

Silicon Metal Powder

Silicon powder is silicon that has been ground into a finely powdered dust. Depending on the purity of the silicon powder, it can be used for many purposes. It can be sintered, alloyed with metals to harden the mixture, made into microchips, used as a reactant in silicon compounds, or used in glass plasma deposition. Powdered silicon usually is made without any additional elements, but it can be mixed with elements such as carbon or oxygen to create different powders.
Silicon is the second most abundant element on Earth and, as such, has been used for many purposes. Unlike many other powders commonly used in metallurgy, silicon is not a metal but a metalloid, or an element that has metal-like properties but is not technically a full metal. Its lack of metal status means silicon powder is not made the same as metal powders are. The typical way of turning silicon into fine powder is to use industrial grinders to pulverize the material to a certain grade, depending on the powder’s intended use.

There are different purity levels of silicon powder, with lower levels having trace inclusions of other elements. The lower level of purity is around 98.5 percent and is mostly used by metallurgists as an alloying material to harden metals such as iron and aluminum. Chemists also use this as a reactant material in organic silicon mixtures and compounds. Higher-level purities, around 99.9 percent and 99.99 percent, are used in glass plasma deposition, or depositing silicon vapor onto a substrate to coat it with silicon.

The use of silicon powder by metallurgists is not limited to alloying; it can also be used in sintering. Silicon sintering is the process of pushing the powdered silicon into a cast and then heating it until the powder becomes a solid. Silicon, as both a powder and a solid, also is used in many electronics, such as in computer microchips and semiconductor parts. Powdered silicon also is used to manufacture solar energy cells.

Silicon powder commonly is made without the inclusion of other materials, but there are several popular mixtures that use other elements. Silicon dioxide is the mixture of silicon and oxygen and is used commonly to coat glass and to create glass under extreme heat and pressure. Silicon carbide, which combines silicon and carbon, is used in making ceramics, bulletproof vests and vehicle parts such as brakes and clutches.

Iron Ore

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, deep purple, to rusty red. The iron itself is usually found in the form of magnetite, hematite, goethite, limonite or siderite.

Ores carrying very high quantities of hematite or magnetite (greater than ~60% iron) are known as “natural ore” or “direct shipping ore”, meaning they can be fed directly into iron-making blast furnaces. Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel. 98% of the mined iron ore is used to make steel. Indeed, it has been argued that iron ore is “more integral to the global economy than any other commodity, except perhaps oil”.

Electrolytic Manganese Metal

Electrolytic manganese is a pure form of the metallic element manganese, Mn. It is termed “electrolytic” because a major step in the refining process involves electrolysis, a chemical reaction driven by an electric current. Less pure forms, such as ferromanganese and silicomanganese, are derived by more economical methods. The pure metal is primarily used as an alloy in the production of stainless steel and aluminum. Electrolytic manganese is also used extensively as an element in lithium-ion batteries designed for electric vehicles.

The initial stages of manganese processing involve heating the ore and using chemical treatments to remove the majority of impurities. Electrolysis is then used to further refine the metal. A solution of the material is placed in an electrolytic cell and a direct electrical current is passed through. The direct current induces a chemical reaction that separates the manganese from naturally occurring contaminants.

Electricity enters the cell through the anode, a negative electrode, and exits through the cathode, a positive electrode. Passing a direct current through the manganese solution can cause either oxidation, a loss of electrons, or reduction, a gain in electrons. This results in electrolytic manganese metal (EMM) collecting on the positive cathode and electrolytic manganese dioxide (EMD) collecting on the negative anode. The electrodes are removed periodically and the manganese deposits collected in the form of flakes. Heating the flakes to 925°F (500°C) removes latent hydrogen and results in a manganese powder with purity in excess of 99.9%.