Green extraction of sunscreen ingredient titanium dioxide
used in cosmetics products and sunscreens, has been developed by
scientists at the University of Leeds.
Titanium dioxide powder is used in a wide range of industries as a white pigment, including cosmetics, paint, paper and plastics. In addition its UV protective qualities make it a common ingredient in sunscreen products. Titanium dioxide is not pure in nature Titanium dioxide does not occur in its pure form in nature, instead it is bound to other metals such as iron and aluminium and extraction mechanisms can have a significant environmental toll. However, scientists from the University of Leeds claim to have developed a greener and cheaper mechanism to extract and purify the titanium dioxide. The current mechanism for extracting and purifying titanium dioxide generates toxic and hazardous wastes that can be difficult and expensive to dispose of, according to the scientists led by Professor Jha. Jha's process involves roasting the mineral ore with alkali to remove the contaminants, instead of treating it with large quantities of chlorine or sulphuric acid. The residue is then treated with chlorine to produce the powder, however according to Jha the process uses 20 times less chlorine than the current titanium extraction process. Furthermore, the purity of the resulting titanium dioxide will be higher than that produced with the current method, reducing production and waste disposal costs, the scientists claim. Recycling the waste products The contaminant metals removed by the alkali in the first stage will not be wasted. Instead they can then be treated and used in the electronics industry, said Jha, giving the example of Niobium which is often found with lower grade titanium ores. The process also recycles the carbon dioxide given off when the mineral ore is roasted with alkali and effectively captures and recycles the heat involved in the process making the technology even more environmentally friendly. The carbon dioxide is used to regenerate the alkali used in the reaction, Jha told CosmeticsDesign.com. "Our process is a real world breakthrough, because it can be used for both lower and richer grades of ores and it overcomes major environmental concerns about having to neutralise and discharge wastes generated in the process that end up going into contamination ponds," said Jha. The Leeds-based team have formed an industrial partnership with Millennium Inorganic Chemicals to develop the technology on a larger scale.