Discarded Sagger Recovery of Lithium Hydroxide and Cathode Oxides
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Solution Overview
Problem
The challenge is to develop a cost-effective and efficient method for recovering high value-added compounds such as lithium, nickel, and cobalt from discarded saggers used in the production of positive electrode active materials, which are typically discarded due to erosion caused by repeated high-temperature firing.
Innovation Solution
A method involving wet pulverization, solid-liquid separation, wet magnetic separation, Al and Si precipitation reactions, and evaporative concentration is employed to recover positive electrode active materials and lithium hydroxide from discarded saggers. This process includes dry and wet pulverization to achieve a fine powder, followed by magnetic separation to recover the active materials, and chemical precipitation and concentration to recover lithium hydroxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If discarded saggers are used for high-temperature firing repeatedly, then production efficiency is improved, but the sagger surface is eroded by lithium hydroxide and lithium carbonate, leading to decreased heat resistance and eventual discarding
Solution Approach 1:
Instead of discarding eroded saggers, the invention recovers valuable materials (nickel, cobalt, lithium) from the eroded surface deposits, transforming waste into valuable resources and extending the effective utilization of the sagger system
Solution Approach 2:
The erosion by lithium hydroxide and lithium carbonate, which normally degrades the sagger, is converted into a beneficial source of recoverable lithium and other valuable materials, turning a harmful effect into a resource recovery opportunity
2Productivity
If wet pulverization and multiple separation processes are employed to recover materials from discarded saggers, then material recovery efficiency is improved, but the process complexity increases
Solution Approach 1:
The recovery process is divided into distinct sequential stages: wet pulverization to reduce particle size, solid-liquid separation to divide eroded material from bulk sagger, wet magnetic separation to concentrate magnetic particles, and flotation to separate based on surface properties. Each stage targets specific materials and progressively enriches the concentrate
Solution Approach 2:
The invention replaces purely mechanical crushing with wet pulverization using ball mills, which provides finer and more uniform particle size reduction. Chemical and physical separation methods (magnetic separation, flotation) replace simple mechanical sorting, enabling more effective recovery of fine particulate materials deposited on sagger surfaces
3Manufacturing precision
If high-temperature firing is used to synthesize positive electrode active materials, then material quality is improved, but ash and smoke during firing degrade the synthesized materials
Solution Approach 1:
The invention extracts and removes harmful substances (ash, smoke, carbonaceous materials) from the firing environment by capturing them in the sagger eroded deposits, which then become the source of recovered materials rather than contaminants affecting product quality
Solution Approach 2:
The sagger acts as an intermediary that captures harmful substances (ash, smoke, lithium hydroxide, lithium carbonate) during firing, protecting the positive electrode active materials from direct contamination while the captured substances are later recovered as valuable products
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 effectively recovers high-purity lithium hydroxide and positive electrode active materials from discarded saggers, enabling the recycling of valuable materials and reducing the manufacturing costs of lithium-ion secondary batteries.
Implementation Method 1
wet pulverization may involve dry pulverizing the discarded sagger and then performing wet ball milling to obtain finely pulverized discarded sagger
Implementation Method 2
wet magnetic separation to recover a positive electrode active material
Implementation Method 3
mixing hydroxide of alkaline earth metal and an additive with the filtrate obtained from the solid-liquid separation to precipitate a soluble aluminum compound of aluminate as an insoluble material such as calcium aluminum silicate hydrate or ettringite and precipitate a soluble silicon-containing compound as an insoluble material such as calcium silicate hydrate
Implementation Method 4
evaporative concentration to recover lithium hydroxide
Data Source
AI summary
The present invention has the advantage of recovering high-purity lithium hydroxide from a discarded sagger that is to be scrapped, by pulverizing the discarded sagger and then recovering nickel oxide and cobalt oxide, which are positive electrode active materials, through wet magnetic separation, and removing impurities through Al and Si precipitation reactions and evaporative concentration. Therefore, by using the method for recovering a positive electrode active material and lithium hydroxide from a discarded sagger according to the present invention, high value-added lithium and positive electrode active materials may be recovered and recycled from a discarded sagger that is scrapped during the manufacturing process of lithium secondary batteries and thus the method is expected to reduce the manufacturing costs of lithium secondary batteries.