Term of Award

Summer 1997

Degree Name

Master of Technology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Department

Department of Industrial Technology

Committee Chair

Keith Hickman

Committee Member 1

David Williams

Committee Member 2

Charles Perry

Abstract

Titanium dioxide (TiO2) is a white pigment that has a vast variety of uses. The major use of TiO2 is in the paint industry. This is the substance that makes white paint brighter due to the pigment's dispersibility in water (Maher, 1981). Titanium dioxide is also used in paper coatings, plastics, cosmetics, and sunscreen. Scientists from the suntanning industry have been able to micronize titanium dioxide into small particles that make it transparent to the eye but still opaque to the sun's rays (Derg, 1993) . By adding TiO2 to sunscreens, sunbathers are protected from ultraviolet B rays which cause sunburn and from ultraviolet A rays, which slowly destroy the skin's support structure (p.30).

Of all pigments incorporated into plastics, titanium dioxide remains among the most widely used, with a worldwide consumption in the plastics industry of 400,000-500,000 tons a year (Bergado, 1994). The technology surrounding the production and use of TiO2 in the plastics industry is in a constant state of flux. It has changed more in the past decade than in any other comparable period (p.32) .

Titanium dioxide pigments hold a special position, mostly because of a high light-scattering power. This enables a defined brightness level to be achieved in colored plastics and provides the desired opacity (Bergado, 1994) . For exterior applications, it is also necessary to consider the properties that result from adsorption processes and photochemical reactions taking place on the pigment surfaces (p.38) .

Titanium Dioxide is processed from milled ilmenite ore. The ore is mixed with sulfuric acid in the sulfate process of digestion. A rich black liquor is produced and allowed 4-5 hours to settle. Unwanted impurities, and undigested ore settle to the bottom to form a sludge. Currently, the sludge is filtered, neutralized, and landfilled. There is a substantial amount of TiO2 that is lost in this waste sludge. The recovery of this product is currently being investigated.

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