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The Minerals and Chemicals within Glass

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Majority of glass used in our daily glass from jars, bottles, drinking glass and even windows are called soda-lime glass since it uses soda ashes in its production. Glass in general is mainly made out of sand. In fact, sand alone can be fused to produce glass but it requires a high temperature which is estimated about 1700°C for the sand to completely melt. However, to mass produce glass, other chemical and mineral are added to lower the melting temperature to ease the production.
Sodium Carbonate (Na2CO3) also known as soda ash is mixed with sand to produce a product of 75% silica (SiO2) and 25% sodium oxide (Na2O). This mixture will melt and fuse at a much lower temperature of 800°C. Unfortunately, the glass produced with this composition is water-soluble which is also known as water glass. This is not suitable for glass bottle since it need to contain water so, to stabilise the glass, other chemical substance is mixed into the composition such as calcium oxide (CaO) and magnesium oxide (MgO). The chemical mixtures are obtained by the addition of lime stone which produce a pure and inert glass.
The glass produced is originally colourless and transparent. Addition of different chemicals into the production of the glass results in different colour like green blue or brown. Most of glass bottle produced have similar composition of chemicals as their ingredients. The composition of chemicals are 70% - 74% SiO2 (silica) 12% - 16% Na2O (sodium oxide) 5% - 11% CaO (calcium oxide)

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