Glass colouring: Rare earths for fine colours
Glass is not only available in a variety of shapes and for many different applications, glass also comes in many different colours. Glass colouring takes place during the manufacturing process.
One option for colouring glass is to add iron oxides. Depending on the type of substance added, the glass takes on a specific colour: Sulphur turns the glass yellow while copper oxide or gold turn it red, chromium oxide and iron oxide produce a green tint, and so on.
In addition to oxides, rare earths can also be used for colouring glass. And sometimes a contamination in one of the glass ingredients even creates an unwanted colour in the glass. In these cases, the principle of complementary colours is applied.
An opposing colour is added to neutralise the unwanted colour. Glass colouring requires experts with a great deal of experience. In an industrial environment, computers calculate the correct mixing ratio.