Lithium Extraction via Sulfate Roasting and Water Leaching
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Solution Overview
Problem
Current technologies face challenges in economically extracting lithium from low-grade lithium-bearing materials such as waste rock, tailings, and clay formations, due to low concentrations and high operational costs.
Innovation Solution
A process involving mixing lithium-bearing material with gypsum, a sulfur-containing material, and a calcium-containing material, followed by drying, roasting, and leaching, to form a water-soluble lithium compound that can be extracted using an aqueous solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional extraction methods are used on low-grade lithium-bearing material, then lithium can be extracted, but the extraction cost is high and recovery is low
Solution Approach 1:
The patent changes the chemical parameters of the extraction system by using sulfur-containing materials (such as sodium sulfate, potassium sulfate, or elemental sulfur) combined with calcium-containing materials to create a roasting mixture that converts lithium-bearing minerals into water-soluble lithium compounds. This parameter change enables effective lithium extraction from low-grade materials at lower costs while achieving up to 5% higher recovery rates compared to traditional methods.
Solution Approach 2:
The patent employs inexpensive, readily available materials such as gypsum, elemental sulfur, sodium sulfate, potassium sulfate, and calcium-containing materials (limestone, dolomite, or lime) for the roasting process. These cheap reagents enable economical processing of low-grade lithium-bearing materials, directly addressing the high extraction cost issue while maintaining effective lithium recovery.
2Productivity
If sulfur-containing materials and calcium-containing materials are added to the mixture, then lithium recovery is enhanced, but the process complexity increases
Solution Approach 1:
The patent combines multiple materials (lithium-bearing material, sulfur-containing material, and calcium-containing material) into a single roasting mixture that is processed in one continuous operation. This merging of materials and operations simplifies the overall process while achieving enhanced lithium recovery, as the sulfur and calcium materials work synergistically during roasting to convert lithium minerals into water-soluble compounds.
Solution Approach 2:
The roasting mixture self-regulates during the roasting process, where the sulfur-containing materials and calcium-containing materials react with the lithium-bearing minerals to automatically form water-soluble lithium compounds. This self-service mechanism reduces the need for complex process control, monitoring, and adjustment systems, thereby lowering process complexity while maintaining high lithium recovery.
3Object-affected harmful factors
If water-based leaching is used instead of acidic solutions, then environmental impact is reduced, but leaching efficiency may be affected
Solution Approach 1:
The patent fundamentally changes the leaching parameter from acidic conditions to neutral water-based conditions. By pre-roasting the lithium-bearing material with sulfur-containing and calcium-containing materials, the lithium is converted into water-soluble compounds (such as lithium sulfate), which then can be efficiently leached using simple water. This parameter change eliminates the environmental harm of acid waste while maintaining high leaching efficiency.
Solution Approach 2:
The patent performs a preliminary roasting action before leaching, where sulfur-containing materials and calcium-containing materials are heated with the lithium-bearing material to convert the lithium minerals into water-soluble forms. This preliminary action prepares the material for subsequent water-based leaching, ensuring high leaching efficiency is achieved even though neutral water is used instead of acidic solutions, thereby reducing environmental impact.
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 method enhances lithium recovery by up to 5% compared to traditional methods, reduces operational costs by using on-site generated sulfur-containing materials, and employs environmentally benign water-based leaching instead of acidic solutions.
Implementation Method 1
mixing the lithium-bearing material, gypsum, a sulfur-containing material, and a calcium-containing material and forming a feed mixture... roasting the dried mixture and forming a roasted mixture including a water-soluble lithium compound
Implementation Method 2
leaching lithium from the water-soluble lithium compound and forming a lithium-containing leachate by mixing the aqueous solution and the water-soluble lithium compound
Implementation Method 3
drying the feed mixture to form a dried mixture having a moisture content of less than 20 wt %
Data Source
AI summary
A method of extracting lithium from a lithium-bearing material including: (i) mixing the lithium-bearing material, gypsum, a sulfur-containing material, and a calcium-containing material and forming a feed mixture having a moisture content of at least 20 wt %; (ii) drying the feed mixture to form a dried mixture having a moisture content of less than 20 wt %; (iii) roasting the dried mixture and forming a roasted mixture including a water-soluble lithium compound; and (iv) leaching lithium from the water-soluble lithium compound and forming a lithium-containing leachate by mixing the aqueous solution and the water-soluble lithium compound.