Rutile is the most common and stable form of titanium dioxide found in nature. It forms under high pressure and high temperature in igneous and metamorphic rocks. It is a key ingredient in paint and also a useful component in optical equipment.
Properties
| Type | Mineral |
| Crystal System | Tetragonal ditetragonal dipyramidal |
| Mineral Classification | Oxide |
| Color | Reddish-brown, red, pale yellow, pale blue, violet, rarely grass-green, or black |
| Chemical Formula | TiO2 |
| Luster | Adamantine to submetallic |
| Streak | Bright red to dark red |
| Fracture | Uneven to sub-conchoidal |
| Mohs Hardness | 6.0 - 6.5 |
Relation to Mining
Rutile is recovered through surface mining and dredging of dense beach sands.
Uses
Because it has a very high index of refraction, rutile is used for many purposes in optics. A vast majority of these optical applications come from synthetic rutile, which was first produced in 1948. As a source of titanium dioxide pigment, rutile is used in plastics, paper products, paints, sunscreen, and even food coloring. Certain welding equipment also uses it.
Rutile Beneficiation Process
Gravity Separation
In the rutile ore beneficiation process, gravity separation has two main uses: sorting coarser-grained rutile ore, and tailing fine-grain rutile. It is generally used for pre-treatment before flotation, which can effectively remove slime and part of the gangue.
Generally, spiral chutes are used for desliming, and shaking tables are used for separating rutile, quartz, garnet, and other minerals.
Magnetic Separation
Rutile is often associated with magnetic minerals such as ilmenite, titanomagnetite, garnet, and vermiculite, as well as weak magnetic minerals such as amphibole and epidote. Rutile itself is non-magnetic, so it can be separated by magnetic separation.
In the rutile beneficiation process, magnetic separation is commonly used to remove magnetic minerals and further purify rutile coarse concentrates.
Magnetic separation equipment mainly includes SLon high gradient magnetic separator, permanent magnet double roller magnetic separator, and SHP strong magnetic separator.
Electric Separation
Rutile is a good conductor of electricity, while minerals such as silicate, zircon, and leucoxene are non-conductive. This makes it easier to separate rutile from other non-conductive minerals by electric separation.
Electric separation equipment mainly includes high-pressure double-roller electric separator, high-voltage corona electric separator, and cyclone electric separator.
Flotation
Most of China's rutile resources are low-grade primary ore, which is difficult to separate by a single process such as gravity separation, electric separation, or magnetic separation. Flotation is an important means to solve the beneficiation of fine-grain rutile ore.
Acid Pickling
Rutile concentrate products require a TiO2 content of more than 85% and have strict limits on impurity contents such as S and P. After rutile ore is sorted by conventional beneficiation methods, the crude concentrate still contains some impurities such as silicate and iron minerals. To improve the quality of rutile concentrate, rutile can be further purified by acid pickling.
Biological Desiliconization
The TiO2 grade of rutile obtained by conventional beneficiation methods is generally about 80%, and a small amount of silicate and iron minerals are difficult to remove. Conventional purification methods include roasting and acid pickling. However, the acid pickling process is not only dangerous to operate but also pollutes the environment.
