Reactive Crystallization of Salts Dissolved in the Sea Water

Carbon dioxide is considered to be one of the main factors of global warming. To fix carbon dioxide gas produced by factories, carbon dioxide is reacted with available resources in sea water to precipitate as carbonates. In this thesis reactive crystallizations of magnesium and lithium ions with carbon dioxide are discussed. Magnesium carbonate is popularly used as an anticaking agent and lithium carbonate as the material for lithium ion batteries. The production mechanism of basic magnesium carbonate precipitated from magnesium hydroxide with carbon dioxide was investigated. The effects of the reaction temperature and the initial concentration of magnesium hydroxide on the properties of basic magnesium carbonate particles were experimentally studied. The ability of anticaking agents was also measured. We studied the fundamental mechanism of reactive crystallization of lithium carbonate between concentrated lithium solution obtained through the adsorption process from seawater and carbon dioxide. The effects of operating factors, that is, the initial concentration of lithium hydroxide, reaction temperature and impeller speed on the crystallization characteristics, meaning the nucleation rate and crystal growth rate, were investigated using an MSMPR crystallizer. To commercially apply these processes, a feasibility study of production and further developments of needs is necessary. We hope these investigations will encourage corporate social responsibility (CSR) for global warming countermeasures.