Marios Constantinou, from Cyprus-Greece and now attending Valdosta State University in Valdosta Georgia U.S.A. , Psychology Major and plan to attend Graduate School next year. My topic is on: what is Titanium and Titanium Dioxide (Rutile); how they are mined and where they could be found.What is TiO2? What are its properties? -TiO2 is a soft solid and melts at 1800 0C -It is polymorphous and it exists in three types of crystal structures: (a) rutile, (b) anatase and (c) brookite. Only rutile is used commercially.
RUTILE: - has density of 4.2g/cc - is colorless (but it is used for pigmentation) - as a chemical is Dielectric - absorbs ultraviolet light - has high stability - has a pH of 7.00-8.3 when present as a solid in solution - is composed by 94% of TiO2 and Alumina - only diamond has a higher refractive index (how it bends light) than rutile.
Functions/Applications of Rutile >It is a pigment for whitening paints, plastics, inks, fibers, papers, coatings, food and cosmetics (It is the most used white pigment in the world). >It is used in electroceramics and glass (due to its high stability and property to absorb ultraviolet light). >It is an excellent reflector thus it is used in solar observatories where heat makes observing impossible. > It is used widely as a sunblock in suncreames because: is a physical sunblock; it reflects, absorbs and scatters light; it is a broad spectrum sunscreen; it does not irritate skin and it is water resistant.
Where big reserves of TiO2 exist: 1. Southeast Canada 2. Southeast USA 3. Southwest Scandinavia 5. Midwest and South Africa 6. Mediterranean Sea 7. East Australia
How is it mined and processed?(1)
The process used to mine TiO2 is called AStrip Mining. @Steps of Strip Mining:(see also figure 1) The potential land should be first striped bare of vegetation, top soil should be striped also. If the mining is done near water a pond 40-50 feet deep is created and is filled up with natural water. Then, a dredge separates minerals and dirt; dirt is refed in a pit and once more remaining minerals and dirt are separated. Furthermore, the dredge and pit deplete minerals and minerals are taken in further process. Floating on the pond a Wet Mill separates minerals from the rest dirt according to their gravitational weight. This is succeeded with spirals of the Wet Mill; spirals are fed with dirt/minerals and in the spirals the lighter dirt is carried away and the heavy minerals sit on the bottom of the spirals. Finally, mixed dried Minerals are transported to Dry Mills in which the actual separation of titanium oxide takes place. Conductivity and magnetism are used here to separate minerals. High tension mineral separators will separate conductive and non conductive minerals. Rutile is turned into a pigment after is bathed either with Sulfuric Acid (Sulfate Process) or Chlorine (Chloride Process).
Facts about mining and processing titanium Oxide: - Mining process could bring air, light and noise pollution. - This kind of mining (Strip Mining) usually is active for 50 years in a certain area; after mining process finish land is replanted, but it takes minimum four years for the vegetation to spread in such land.
- Rutile could be also mined in one of the
purest forms, rutile- beach sand.
Figure 1(1):
Rutile Cost: about $10 per ton.
Ti (TITANIUM): what is it and properties: - metal (ninth most abundant element on earth) - pure metal is 99.6% - it density is 4.5g/ML - melting point, 1943 K; boiling point, 3562 K - heat of vaporization and fusion 421 kj/mol and 15.45 kj/mol respectively - specific heat 0.52 j/gK - it burns in air and it is the only metal that burns in Nitrogen. - when pure it is lustrous, white - excellent corrosion resistant - strong as steal and 45% lighter - 60% heavier than aluminum and twice as strong. - it has low module of elasticity and low coefficient of expansion - it is not magnetic
Functions and applications > Titanium alloys with aluminum, molybdenum, manganese, iron etc are used for aircraft and missile building because of its lightness, strength and ability to stay unchangeable in high temperatures. > Titanium is resistant to sea water so it is used for propellers, riggings and other ship parts. > Titanium in Medicine: it is used to make artificial body parts; implants; surgical devices; pacemaker cases and centrifuges. Ti is used so widely in medicine because it has total resistance to body fluids. >Titanium is used in devices that transfer heat (high temperature does not effect Ti) as condensers, tube heat exchanger in power plants, a.c. particles, oil platforms etc. >Titanium=s electrochemical properties make it energy efficient unit for production of chlorine products. >Ti handles excellent chlorine gas and it is used to keep chlorine chemicals.
Why is such good material for thousand of applications? Generally is good for all of the above applications and thousand others because of its strength, resistance to erosion and erosion corrosion. Ti has also very thin conductive oxide surface so its surface promotes dropwise condensation. (See also it properties above)
Where Ti could be found? 1. On meteorites and sun. 2. On earth in igneous rocks. 3. In ash, plants and animal bodies.
How is it mined? Soil containing Ti is transported in process factories. Titanium is then produced by reducing titanium tetrachloride with magnesium. Finally, the metal is purified by decomposing its iodide.
Price of commercial Ti in powder
form (99.95%): About $100
per pound.
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(1): Stouffer, N., W. Mining For
Heavy Minerals. E. I. Du Pont De Nemours & Co., Inc. - http://setec-astronomy.mit.edu/chemicool/titanium. html - http://w.nl-ind.com/kronos/manufacturing2.html - http://www.collabo.com/tios.htm#Overview |