Testing procedures for CO2 uptake assessment of accelerated carbonation products: Experimental application on basic oxygen furnace steel slag samples

Many CO2 reactive by-products from industrial processes can be valorised via carbonation to produce building materials. The amount of CO2 captured in mineralisation processes is environmentally and economically relevant, however results from the literature are often controversial owing to a lack of standardisation in the existing CO2 quantification techniques. In this study testing procedures for the assessment of carbonation efficiency are outlined and applied on basic oxygen steel slag samples providing CO2,uptake estimates ranging from 13.3% to 17.0%. Thermogravimetry, thermal decomposition and acid digestion, emerged as valuable techniques for carbonates quantification that can be adopted on samples of different nature, i.e. powders, pastes and mortars. Advantages and drawbacks of each method are discussed, and their field of application is defined. A comparison of the experimental results with similar studies from the literature is reported as well.