Efficient Lithium Processing: Reducing Na2SO4 Byproducts
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Summary
Problems
Current methods for processing hard rock lithium minerals to produce lithium carbonate (Li2CO3) and lithium hydroxide monohydrate (LiOH—H2O) result in significant production of Na2SO4 byproduct, high capital investment, energy consumption, and CO2 emissions, limiting economic viability and marketability, especially outside of Asia.
Innovation solutions
A method involving the preparation of an aqueous feed solution by reacting lithium-containing materials with sulfuric acid, followed by reaction with sodium hydroxide to produce a first intermediate solution comprising lithium hydroxide and sodium sulfate, allowing for the separation of lithium hydroxide and subsequent reaction with carbon dioxide to produce lithium carbonate, while utilizing CO2 from flue gas and recycling sodium hydroxide, reducing the need for Na2SO4 and NaOH.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the conventional sulfuric acid process is used to produce lithium carbonate or lithium hydroxide from hard rock, then reliable lithium production is achieved, but significant amounts of Na2SO4 byproduct are generated requiring extensive crystallization facilities and increasing capital investment
Why choose this principle:
The patent extracts and removes the Na2SO4 byproduct from the lithium production process using a specialized extraction circuit that separates sodium sulfate from the lithium hydroxide product stream. This allows the main lithium production line to operate without extensive crystallization facilities, as the Na2SO4 is selectively removed and handled in a dedicated extraction system rather than requiring large-scale crystallization equipment.
Principle concept:
If the conventional sulfuric acid process is used to produce lithium carbonate or lithium hydroxide from hard rock, then reliable lithium production is achieved, but significant amounts of Na2SO4 byproduct are generated requiring extensive crystallization facilities and increasing capital investment
Why choose this principle:
The patent introduces an intermediary substance or process step that facilitates the separation of Na2SO4 from the lithium product. The extraction circuit uses an intermediary extraction mechanism that enables selective removal of sodium sulfate without requiring the conventional extensive crystallization infrastructure, thereby reducing device complexity while maintaining production reliability.
Application Domain
Data Source
AI summary:
A method involving the preparation of an aqueous feed solution by reacting lithium-containing materials with sulfuric acid, followed by reaction with sodium hydroxide to produce a first intermediate solution comprising lithium hydroxide and sodium sulfate, allowing for the separation of lithium hydroxide and subsequent reaction with carbon dioxide to produce lithium carbonate, while utilizing CO2 from flue gas and recycling sodium hydroxide, reducing the need for Na2SO4 and NaOH.
Abstract
Methods are provided for processing a lithium-containing material, such as spodumene, whereby a lithium sulfate solution derived from the material is reacted with sodium hydroxide to produce an intermediate solution comprising a first and second portion comprising lithium hydroxide and sodium sulfate. Lithium hydroxide and sodium sulfate are produced from the first portion. Lithium carbonate and sodium sulfate are produced from the second portion by reacting the intermediate solution with carbon dioxide. The intermediate solution may also be subjected to freezing thereby separating the lithium hydroxide from the sodium sulfate, and the separated lithium hydroxide may be reacted with carbon dioxide to produce a lithium product comprising lithium carbonate. Sodium sulfate from these processes may be reacted with an alkali chemical to produce a byproduct and a sodium hydroxide reaction fluid. The reaction fluid circulated in a continuous closed-loop into the reaction system to produce LiOH/Na 2 SO 4 intermediate solution.