Application of a mechanochemical method for recycling waste glass with CO2 solidification

A mechanochemical method for treatment of powdered (recycled) waste glass and calcium hydroxide is combined with a CO2 solidification process for strength development of solidified products. Our work has potential for reducing CO2 emission, which has been identified as a major cause of global warming. Poorly crystalline pre-pulverized waste glass cullet and calcium hydroxide powder was mixed with similar to70 wt % water and cured at room temperature, prior to CO2 carbonation, to produce a solidified sample. Solidified samples were heated to examine phase transformations. Sample density, Vickers hardness and flexural strength were determined. Effect of grinding time, Ca/Si ratio and water content on the mechanical properties was investigated. The mechanochemical reaction has a strong influence on the hardening process, due to formation of calcium carbonate. TG-DTA results show that the decomposition temperature of the glass/calcium hydroxide mixture is decreased after mechanochemical treatment, indicating enhanced reactivity of the mixture. Vickers hardness is increased after CO2 solidification. Our method is effective for the production of various building materials.