Alkaline digestion of waste glass

There is a narrow range of reaction conditions under which the alkaline digestion of soda-lime glass and separation of resultant products is able to proceed in a commercially relevant way.

UQ researchers have optimised digestion conditions and product processing, such that glass can now be used to produce a range of high-value products including liquid alkali-silicates in all commercially relevant concentrations and ratios, high purity silica gel and Calcium Silicate Hydrate (CSH).

Key features

• Simple process developed for the extraction of sodium silicate from soda-lime glass, characterised by a high utilisation of the raw materials and energy embodied in glass
• Suitable for the low-value fraction of waste glass which is too small to be optically sorted (by colour) and remade into glass products
• Significant commercial (reduced capex and opex) and social benefits (reduce landfill and consumption of virgin materials) when compared to conventional production routes of sodium silicate.