Titanium dioxide: the whitest white
This compound is often used in powder form to make paints less transparent and has a characteristic bright white colour. Titanium dioxide is very good at reflecting light so vibrantly coloured paints can be produced by adding small amounts of pigments. The vast array of paints and hues available today are thanks to the high reflectivity of titanium dioxide. It can also be used to make UV-protective coatings.
A major advantage of titanium dioxide pigments are that they are non-toxic so they have replaced the toxic lead-containing chemicals that were used in the past.
Titanium dioxide is made by reacting chlorine gas with titanium sands which are typically black in colour due to the high number of impurities they contain. The chlorine is then recovered, leaving behind the white-coloured pure titanium dioxide. The chlorine used in the production process is largely recycled and used to react with more impure titanium dioxide.
Titanium dioxide is also produced via the so-called sulphate process route, using sulphuric acid.
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