Lithium Hydroxide Production from Lithium Sulfate Without Electrolysis

The patent replaces the electrolysis process (electrical/chemical system) with a chemical reaction system using calcium hydroxide or barium hydroxide. Instead of using electricity to convert lithium carbonate to lithium hydroxide, the invention uses chemical precipitation reactions where calcium hydroxide or barium hydroxide reacts with lithium carbonate to form lithium hydroxide and calcium carbonate or barium carbonate precipitates, which are then filtered out. This substitution eliminates the high energy costs and equipment requirements of electrolysis.

The patent changes the chemical parameters of the reaction system by introducing calcium hydroxide or barium hydroxide as reagents. This parameter change transforms the reaction pathway from electrolysis to chemical precipitation, allowing lithium hydroxide to be produced through solution chemistry rather than electrochemical processes, thereby reducing production costs while maintaining product quality.

The patent combines multiple process steps into a single integrated reaction system. Instead of separating the conversion of lithium sulfate to lithium carbonate and then to lithium hydroxide into distinct stages, the invention directly reacts lithium sulfate with calcium hydroxide or barium hydroxide in one step to produce lithium hydroxide and calcium sulfate or barium sulfate precipitates. This merging of steps simplifies the overall process flow and reduces the number of intermediate handling operations required.

The patent extracts and removes the intermediate lithium carbonate step from the traditional multi-step process. By directly reacting lithium sulfate with calcium hydroxide or barium hydroxide, the method eliminates the need to isolate and process lithium carbonate as an intermediate product, thereby reducing process complexity and the number of unit operations required.