Waste Sagger Lithium Carbonate Recovery via Anion Exchange Purification
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Solution Overview
Problem
There is no effective method for recovering high-purity lithium carbonate from waste sagger discarded after use in high-temperature firing for lithium secondary battery production, leading to waste accumulation and increased production costs.
Innovation Solution
A method involving crushing, alkali leaching, anion exchange, carbonation, pressurized carbonic acid dissolution, and heating fractional precipitation to recover high-purity lithium carbonate from waste sagger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If waste sagger is discarded after use in high-temperature firing, then production costs increase due to loss of valuable lithium compounds, but recovering high-purity lithium carbonate requires complex multi-step processing
Solution Approach 1:
The recovery process is divided into multiple sequential steps: crushing the waste sagger, alkali leaching to extract lithium compounds, solid-liquid separation, anion exchange to purify the lithium solution, carbonation to precipitate lithium carbonate, and drying. Each step targets specific impurities or transformation requirements, enabling high-purity recovery despite the multi-step complexity
Solution Approach 2:
Anion exchange resin is introduced as an intermediary substance to selectively remove harmful anions (such as carbonate and hydroxide ions) from the lithium-containing solution. This mediator enables high-purity lithium carbonate recovery by transforming the purification step into a controlled chemical exchange process rather than simple filtration
2Manufacturing precision
If multiple processing steps are implemented to achieve high purity lithium carbonate, then product purity increases to 99.9% or greater, but production time and energy consumption increase
Solution Approach 1:
The waste sagger is first crushed into fine particles before leaching, which pre-prepares the material for more efficient lithium extraction. This preliminary mechanical processing reduces the subsequent leaching time and improves the overall efficiency of the multi-step recovery process
Solution Approach 2:
The process utilizes controlled changes in chemical parameters (pH, temperature, concentration) at each step to optimize both purity and processing time. For example, the carbonation step uses controlled CO2 gas flow and temperature to precipitate lithium carbonate efficiently, while the anion exchange step uses controlled flow rates to achieve high purity without excessive processing time
3Productivity
If waste sagger is used repeatedly for high-temperature firing, then productivity is maintained, but the sagger deteriorates due to surface erosion from lithium hydroxide and lithium carbonate deposition
Solution Approach 1:
The lithium compounds that cause the sagger to deteriorate through surface erosion and deposition are converted into a valuable product. By recovering lithium carbonate from the waste sagger, the harmful effect of lithium deposition is transformed into a beneficial resource, simultaneously addressing the reliability issue and creating economic value
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
The method achieves lithium carbonate purity of 99.9% or greater, enabling recycling and reducing production costs by recovering valuable lithium compounds from waste sagger.
Implementation Method 1
performing an anion exchange reaction by allowing the filtrate to flow through an anion exchange resin
Implementation Method 2
adding an alkali leaching agent and water to the waste sagger crushed material and then allowing a reaction to occur therebetween
Implementation Method 3
performing pressurized carbonic acid dissolution reaction on a solid phase obtained through the secondary solid-liquid separation
Implementation Method 4
performing a heating fractional precipitation reaction on a filtrate obtained in a liquid phase through the tertiary solid-liquid separation
Data Source
AI summary
The present invention provides an optimized method for recovering high-purity lithium carbonate from a lithium-containing composite oxide deposited on an eroded surface of a waste sagger discarded. Therefore, when the method for producing high-purity lithium carbonate from a waste sagger of the present invention is used, it is expected not only to be able to produce high-purity lithium carbonate that can be used for manufacturing lithium secondary batteries by recycling a discarded waste sagger, but also to be able to recycle a positive electrode active material, iron oxide, alumina, silicate, and calcium carbonate obtained as by-products during the production process of the lithium carbonate.