Titanium Powder Metallurgy
Production of TiO2 Pigment
A New Energy Efficient Method for Production of TiO2 Pigment – Eliminating Direct CO2 Emission
The overall objective of this projec is to demonstrate the validity and potential of a new concept for making titanium dioxide (TiO2) pigment without CO2 emission. By replacing the traditional chloride process which relies on high temperature chlorination, which includes a simultaneous reaction of carbon with oxygen (hence producing large quantities of CO2), the proposed new method uses a methodology of sequential chemical treatments and extractions to produce pure TiO2. The new method produces dramatically less CO2, consumes significantly less energy, and produces significantly less environmental waste.
Since its commercial production in the early twentieth century, titanium dioxide (TiO2) has been widely used as a pigment in paints, ointments, toothpaste, sunscreens, and many other industrial and consumer applications. In more recent decades, the applications of TiO2 have expanded, and are still expanding in photovoltaic generation of power, photocatalytic splitting of water for producing hydrogen, as well as biomedical and electronic technology areas.
Given the enormous markets for TiO2 pigment, the production of TiO2 is, needless to say, a mega-size industry. Unfortunately, however, the manufacturing of TiO2 is also a mega-size energy intensive and eco-unfriendly industry. Conventionally, TiO2 is produced from either ilmenite, or titania slag, or synthetic rutile, using either sulfate process or a chloride process. Because the sulfate process produces large volumes of acidic liquid wastes and consumes considerably more energy due to its multi-step energy intensive batch processing procedures, the chloride process is the more dominant process in developed countries.
The chloride process was first developed by DuPont in the late1950s. It involves less complicated steps than the sulfate process, but it relies on chlorination and oxidation at extremely high temperatures (1300~1800°C), and releases large quantities of CO2. However, given the environmental and social pressures today, there are significant needs and incentives for developing new processes that reduce or eliminate CO2 emissions. The goal of this project is therefore to investigate and demonstrate a new concept and methodology that can be used to develop new commercial processes for production of TiO2 pigment, replacing the chloride process. This new technology will not only eliminate a major CO2 emission step, but also reduce energy consumption by up to 50% because the Ti-O bond in the raw material (titanium ore – ilmenite) will not be broken and then re-formed in the process as in the traditional processes. The new method will also produce near-zero environmental waste. In short, if successful, the environmental benefits and energy savings will be immensely significant.