Ring-opening polymerisation of epsilon-caprolactone in supercritical carbon dioxide is slowed down by a carbonation reaction, resulting in a positive volume of activation and a higher energy of activation as compared to polymerisation in a regular hydrocarbon solvent.

The structural changes induced by accelerated carbonation in alkali-activated slag/ metakaolin (MK) cements were determined. The specimens were carbonated for 540 h in an environmental chamber with a CO2 concentration of 1.0 ± 0.2%, a temperature of 20 ± 2°C, and relative humidity of 65 ± 5%. Accelerated carbonation led to decalcification of the main binding phase of these cements, which is an ...

Thermal decomposition of dolomite in the presence of CO2 in a calcination environment is investigated by means of in situ X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The in situ XRD results suggest that dolomite decomposes directly at a temperature around 700 °C into MgO and CaO. Immediate carbonation of nascent CaO crystals leads to the formation of calcite as an intermediate...

The production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste can be achieved by thermally reducing the waste into calcium sulphide (CaS), which is then subjected to a direct aqueous carbonation step for the generation of hydrogen sulphide (H2S) and CaCO3. H2S can subsequently be converted to elemental sulphur via the commercially available chemical catalytic Claus process...

Emission of CO2 from different sources has increased the effect of green house gases and global warming. Fixation of CO2 from atmosphere in the form of solid carbonates appears to be an option for reduction of CO2 concentration. Mineral carbonation is a process of chemical reaction in which minerals or its residues consisting of lime and magnesia become a source of carbonation. The material fly...

Various therapeutic approaches for dysphagia management are based on modifications of bolus properties to change swallowing biomechanics and increase swallowing safety. Limited evidence exists for the effects of carbonation and bolus temperature on swallowing behavior. Here, we investigated the effects of carbonation and temperature on swallowing behavior using a novel automated and complex swa...

Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key proces...

This report describes a novel way to generate a highly effective hydrophobic cement surface via a carbonation route using sodium stearate. Carbonation reaction was carried out at different temperatures to investigate the hydrophobicity and morphology of the calcium carbonate formed with this process. With increasing temperatures, the particles changed from irregular shapes to more uniform rod-l...

16 17 The global warming of Earth's near-surface, air and oceans in recent decades is a direct 18 consequence of anthropogenic emission of greenhouse gases into the atmosphere such as CO2, 19 CH4, N2O and CFCs. The CO2 emissions contribute approximately 60% to this climate change. 20 This study investigates experimentally the aqueous carbonation mechanisms of an alkaline paper 21 mill waste con...

There is increasing interest in CO2 looping cycles that involve the repeated calcination and carbonation of the sorbent as a way to capture CO2 from flue gases during the carbonation step and the generation of a pure stream of CO2 in the oxyfired calcination step. In particular, attrition of the material in these interconnected fluidized bed reactors is a problem of general concern. Attrition o...