3. Glass and metal cleaning

Glass is a non-crystalline (amorphous) solid in a particular physical state of matter called the vitreous state. It is made up of over 60% silicon oxide (SiO ₂ silica), introduced in the form of sand, sodium oxide supplied by carbonate and serving as a flux that facilitates the melting of the material at around 1,500°C instead of 1,800°C, and alkaline earth in the form of lime or dolomite (natural double oxide of calcium and magnesium). A conventional glass, known as soda-lime glass, may contain, for example, 76% silica, 12% soda and 12% lime. Specific additives can also be incorporated to give the glass particular properties. For example, borosilicate glasses such as Pyrex ^® contain boric anhydride (B ₂ O ₃ ...