Raghavendra Ragipani

Indian Institute of Technology Kanpur | IIT Kanpur · Department of Chemical Engineering

Production of precipitated calcium carbonate (PCC) via carbon dioxide (CO2) pressure-swing mineral carbonation is a potential way to utilise calcium-rich steel slag and carbon dioxide. Calcium supersaturation and slag surface passivation are two aspects of calcium extraction step that strongly influence the choice of operating conditions necessary...

Carbon dioxide sequestration via carbonation of steel slags is a promising way of combining two waste products to create value. Understanding the dissolution kinetics of steel slags, which are alkaline and rich in calcium, in acidic media is essential to configure such a process. In this study, we seek to analyse the dissolution mechanism from expe...

Calcite particles coated with nano-silica find use in applications such as enhanced oil recovery, paper-making, and thermal energy storage. In this study, the surface coating of calcite particles by silica nanoparticles (nano-SiO2) in aqueous solutions assisted by a CO2 environment was investigated. The result indicates that the coating performance...

Mineralization of gaseous carbon dioxide into solid carbonates using alkaline industrial residues such as coal fly ash has a dual advantage of reducing the carbon dioxide footprint of coal power plants and improving ash utilization. However, the slow mineral carbonation rate under atmospheric conditions is a major challenge, especially when using n...

Research pertaining to carbon dioxide sequestration via mineral carbonation has gained significant attention, primarily due to the stability of sequestered \ce{CO2} over geological time scales. Use of industry-derived alkaline wastes...

High-sulfur mixed fly ash residues from semi-dry flue gas desulfurization units in coal-fired power plants are unsuitable for use as supplementary cementitious material (SCM) for concrete production or carbon dioxide utilization. In this work, we explore the potential for upcycling a representative spray dry absorber ash (10.44 wt% SO3) into concre...

Sequestration of CO 2 within stable mineral carbonates (e.g., CaCO 3 ) represents an attractive emission reduction strategy because it offers a leakage-free alternative to geological storage of CO 2 in an environmentally benign form. However, the pH of aqueous streams equilibrated with gaseous streams containing CO 2 (pH < 4) are typically lower th...

Steel slags are generally alkaline with a high calcium content and are viewed as a potential feedstock for carbon dioxide sequestration and utilization, mostly through aqueous mineral carbonation routes. For recovery of multiple metals such as Ca, Fe, Mg, and Si, and generation of value-added products by dissolution and precipitation reactions in a...

Hydrogenous species play critical roles in the synthesis and catalysis applications of mayenite electride. In this work, we investigate their formation energetics and transport mechanisms in mayenite using ab initio simulations. The chemical potentials of various hydrogenous species are established based on static density functional theory calculat...