Becher process
Encyclopedia
The Becher Process is an industrial process
used to upgrade ilmenite
to synthetic rutile..
The mineral
, ilmenite contains 55-65% titanium
as TiO2
, the rest being iron oxide
. The Becher process removes the iron oxide, leaving a residue of synthetic rutile, which is more than 90% TiO2..
by a joint initiative between industry and government. The process was named after Robert Gordon Becher, who invented, developed and introduced the technique to the Western Australian Mineral Sands industry. The process was patented in 1961.
ilmenite that has low concentration
s of chromium
and magnesium
. There are four steps involved in removing the iron portion of the ilmentite:
:
This allows for use of a wide range of ilmenite materials with varying Fe(II) and Fe(III) content to be used in the next step.
Once the Reduced Ilmenite has cooled it is separated from the char by screening, then continues to the next step of the process.
solution with air being pumped through the tank. The tank is being continuously agitated, and the iron will rust and precipitate out of solution, away from the titanium dioxide portion in the form of a slime.
The finer iron oxide is then separated from the larger particles of synthetic rutile.
.
Industrial process
Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry....
used to upgrade ilmenite
Ilmenite
Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....
to synthetic rutile..
The mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
, ilmenite contains 55-65% titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
as TiO2
Titanium dioxide
Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of...
, the rest being iron oxide
Iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...
. The Becher process removes the iron oxide, leaving a residue of synthetic rutile, which is more than 90% TiO2..
History
This technology was developed in the early 1960s in Western AustraliaWestern Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
by a joint initiative between industry and government. The process was named after Robert Gordon Becher, who invented, developed and introduced the technique to the Western Australian Mineral Sands industry. The process was patented in 1961.
Process
The Becher Process is suitable for weatheredWeathered
Weathered is the third album by Creed, released on November 20, 2001. Some versions are enhanced CDs and include videos. It has been certified 6× platinum by the RIAA...
ilmenite that has low concentration
Concentration
In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...
s of chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
and magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
. There are four steps involved in removing the iron portion of the ilmentite:
- Oxidation
- RedoxRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
- AerationAerationAeration is the process by which air is circulated through, mixed with or dissolved in a liquid or substance.-Aeration of liquids:-Methods:Aeration of liquids is achieved by:...
- LeachingLeaching (chemical science)Leaching is the process of extracting minerals from a solid by dissolving them in a liquid, either in nature or through an industrial process. In the chemical processing industry, leaching has a variety of commercial applications, including separation of metal from ore using acid, and sugar from...
Oxidation
Oxidation involves heating the ilmenite in a rotary kiln with air to convert all of the iron in the ilmenite grains to iron(III) oxideIron(III) oxide
Iron oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron oxide , which is rare, and iron oxide , which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main...
:
- 4 FeTiO3 (s) + O2 (g) → 2 Fe2O3·TiO2 (s) + 2 TiO2 (s)
This allows for use of a wide range of ilmenite materials with varying Fe(II) and Fe(III) content to be used in the next step.
Reduction
Reduction is performed in a rotary kiln with pseudobrookite (Fe2O3.TiO2), coal and sulfur, then heated to a temperature greater than 1200 °C. The iron oxide in the mineral grains is reduced to metallic iron to produce reduced ilmenite:- Fe2O3·TiO2 (s) + 3 CO (g) → 2 Fe (s) + 2 TiO2 (s) + 3 CO2 (g)
Once the Reduced Ilmenite has cooled it is separated from the char by screening, then continues to the next step of the process.
Aeration
Aeration involves the removal of the metallic iron created in the last step by "rusting" it out. This is achieved in large tanks that contain 1% ammonium chlorideAmmonium chloride
Ammonium chloride NH4Cl is an inorganic compound with the formula NH4Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of natural, mineralogical form of ammonium chloride...
solution with air being pumped through the tank. The tank is being continuously agitated, and the iron will rust and precipitate out of solution, away from the titanium dioxide portion in the form of a slime.
- 4 Fe (s) + 3 O2 (g) → 2Fe2O3
The finer iron oxide is then separated from the larger particles of synthetic rutile.
Acid Leach
Once the majority of the Iron Oxide has been removed the remainder of it is leached away using 0.5M sulfuric acidSulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
.