@spot_material
hello@spotmaterial.com
Soda lime glass
0.25-1 usd/kg
Soda lime is the most common type of glass, and is used in packaging, products, furniture and lighting. Glass sheet made from much the same ingredients – called float glass due to the process – is just as widely used, but consumed in the most significant quantities as glazing in buildings and automotive applications.
Soda lime glass, also called soda lime silica (SLS), is made by melting together sand (silica), soda ash (sodium carbonate) and lime. Recycled glass is an important ingredient too, because it improves the efficiency of production. Magnesia (magnesium oxide, MgO), alumina (aluminium oxide, AlO) and zirconium (Zr) are used to enhance specific properties. The exact ingredients are adjusted according to the method of production and application requirements. Heated in a furnace to above 1,200 degC, the minerals form a viscous mass of molten glass ready for shaping. At the end of its useful life, it can be recycled without any loss of quality.
Transparency depends on the ingredients. For example, the typical green tint is the result of iron impurities, such as found in sand. Transmission – whether colourless or coloured – is controlled with the addition of additives such as metallic oxides, sulphides or selenides.
Sustainability concerns
Non-renewable ingredients
Raw material generates polluting by-products
Glass is heavier than plastic, but much harder, inert and has far superior resistance to chemicals, odours and weathering. Its many advantageous properties are exploited in packaging, vacuum flasks and cups (thermos), products, furniture and lighting (as well as float glass in architecture and automotive applications).
Highly transparent glass, also known as flint, yields 90% light transmission. In the case of packaging, colours are added to block certain light wavelengths, which can help to further protect the contents from degradation. For example, whereas flint may be used to show-off perfume and wine, brown (amber) is used to package beer and medicine, because the colour absorbs a high proportion of the ultraviolet spectrum and so prolongs the life of the ingredients.
The same glass used in packaging is used to make lighting (lightbulbs and shades), furniture, tableware and lenses, for example, as well as handblown vases, bowls, artwork and decorations. Where higher thermal shock resistance or mechanical properties are required, other types of glass, such as borosilicate or aluminosilicate, are used.
