Gas-Diffusion Electrodes for Onsite Reagent Production in Li Recovery
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Solution Overview
Problem
Existing lithium recovery processes are costly due to the high demand for reagents such as hydrochloric acid, sodium hydroxide, and sulfuric acid, which are typically outsourced, and the purification processes are complex, especially in brine and rock mining operations.
Innovation Solution
The use of a gas diffusion electrode in a membrane electrolysis cell that allows on-site production of these reagents from available brine sources, utilizing a hydrophilic catalyst layer and ion exchange membranes to process salt-containing solutions, thereby reducing the need for external chemicals and simplifying the purification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reagents such as hydrochloric acid, sodium hydroxide, and sulfuric acid are outsourced for lithium recovery processes, then the purification process can be performed, but the operational costs increase and the process complexity increases
Solution Approach 1:
The patent implements self-service by enabling the lithium recovery process to produce its own required reagents (hydrochloric acid, sodium hydroxide, sulfuric acid) through an integrated electrolysis system that processes brine containing lithium chloride. This eliminates the need to outsource these chemicals, allowing the system to serve itself by generating necessary inputs from available brine resources, thereby reducing both operational costs and process complexity while maintaining purification capability
2Productivity
If reagents are outsourced for lithium recovery, then the extraction process can proceed, but operational costs increase
Solution Approach 1:
The system generates its own reagents (hydrochloric acid, sodium hydroxide, sulfuric acid) from brine through electrolysis, eliminating the need to purchase and transport these chemicals externally. This self-sufficient approach directly reduces operational costs while maintaining full lithium extraction capability, as the system produces necessary chemicals on-site from available brine resources
Solution Approach 2:
The patent merges the lithium extraction process with an integrated electrolysis system that simultaneously produces required reagents. By combining what were previously separate processes (extraction and reagent production) into a single integrated system, the patent eliminates the need to outsource chemicals, thereby reducing operational costs while maintaining extraction productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces operational costs by eliminating the need for outsourcing acid and base feed materials and simplifies the lithium extraction process, making it more efficient and cost-effective.
Implementation Method 1
an ion exchange membrane disposed on a surface of the hydrophilic catalyst layer, the ion exchange membrane being configured to exchange ions from the hydrophilic catalyst layer to an opposed surface of the ion exchange membrane
Implementation Method 2
a diffusion layer configured to diffuse a gas
Implementation Method 3
a membrane electrolysis cell for processing a salt-containing solution
Data Source
AI summary
In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.