Strategies for the continuous electrochemically-induced decarbonation of limestone into hydrated lime

Details

Supervisors

Proost, Joris

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

enLime is a product used in various applications, such as in the environment and in cement production. However, its current production is still very carbon intensive, with one ton of CO2 per ton of lime. Recent studies have explored the concept of electrifying its production by transforming limestone into hydrated lime. This would make it possible to decarbonise its production if green energy is used. This work uses a two-compartment electrochemical cell, capable of dissolving CaCO3 and forming Ca(OH)2 thanks to a pH gradient within the cell formed by a cation exchange membrane. This thesis will study the pH of the two compartments that dissolve limestone and precipitate hydrated lime. The precipitate obtained will be analysed by XRD and ICP, enabling it to be characterised. But also why the voltage varies as a function of time. To answer these questions, the fouling of the membrane will have to be analysed to find solutions. These solutions will then be studied to try to prevent membrane fouling. Finally, a second configuration will be studied. This does not precipitate the product during electrolysis, but precipitation occurs after electrolysis in another reactor, thereby avoiding membrane fouling and maintaining a constant voltage. In this configuration, the dissolution and migration of calcium ions will be studied to understand their behaviour. The pH of the two compartments and the cell voltage will also be analysed. Finally, the precipitate obtained after mixing will be investigated using previously used methods.