Waste Sagger Lithium Carbonate Recovery via Alkali Leaching
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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 significant waste generation and resource inefficiency.
Innovation Solution
A multi-step process involving crushing, alkali leaching, solid-liquid separation, carbonation reaction, and recrystallization to extract and purify lithium carbonate from waste sagger, utilizing alkali metal and earth metal hydroxides/oxides, and controlled carbon dioxide injection to enhance purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waste sagger is discarded after use in high-temperature firing, then the sagger loses its thermal durability function, but lithium resources are wasted and environmental pollution increases
Solution Approach 1:
The patent applies the discarding and recovering principle by systematically recovering lithium compounds from waste sagger that has lost its thermal durability function. The multi-step process includes crushing the waste sagger, leaching lithium with alkali solutions, separating lithium carbonate through carbonation reaction, and purifying the recovered lithium carbonate, thereby transforming waste into valuable lithium resources.
Solution Approach 2:
The patent converts the harmful effect of sagger erosion (which causes thermal durability loss and waste generation) into a beneficial process. The eroded lithium-containing materials that would normally be considered waste are recovered through chemical leaching and carbonation reactions, transforming the harmful waste stream into valuable lithium carbonate product.
2Manufacturing precision
If multi-step purification process is implemented, then lithium carbonate purity increases to 99.9%, but process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the purification process into distinct sequential steps: (1) crushing and size reduction, (2) alkali leaching to extract lithium compounds, (3) solid-liquid separation, (4) carbonation reaction to precipitate lithium carbonate, (5) filtration, and (6) drying. Each step targets specific impurities and builds upon the previous step to achieve progressive purification.
Solution Approach 2:
The patent uses an alkali leaching agent as an intermediary substance to facilitate lithium extraction from the waste sagger. The alkali solution acts as a mediator that selectively dissolves lithium compounds while leaving other impurities behind, enabling subsequent separation and purification steps to proceed more effectively.
3Productivity
If alkali leaching agent is used to extract lithium, then lithium recovery efficiency improves, but cost of reagents increases
Solution Approach 1:
The patent optimizes parameters including alkali leaching agent concentration, temperature, and contact time to maximize lithium recovery efficiency while minimizing reagent consumption. By controlling these parameters, the process achieves effective lithium extraction without excessive reagent usage, balancing productivity with material efficiency.
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 high-purity lithium carbonate recovery (99.9%) from waste sagger, enabling recycling of valuable materials and reducing waste, with by-products like positive electrode active materials and alumina being recovered.
Implementation Method 1
adding an alkali leaching agent and water to the waste sagger crushed material and then allowing a reaction to occur therebetween to prepare a waste sagger crushed material dissolution reaction slurry
Implementation Method 2
performing a carbonation reaction on a filtrate obtained in a liquid phase through the secondary solid-liquid separation to prepare a carbonation reaction liquid
Implementation Method 3
heating, thereby recrystallizing, a filtrate obtained in a liquid phase through the quaternary solid-liquid separation to precipitate a second lithium carbonate
Implementation Method 4
evaporating and concentrating a filtrate obtained in a liquid phase through the primary 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 such as lithium silicate, lithium aluminum oxide, or lithium aluminum silicate deposited on an erosion surface of a discarded waste sagger. 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, calcium carbonate, and the like obtained as by-products during the production process of the lithium carbonate.