Nitrate Process for Lithium Hydroxide Precursor Waste Reduction
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Solution Overview
Problem
The existing processes for producing NMC hydroxide precursors for lithium-ion batteries face challenges such as high waste water generation, ammonia and sodium sulfate discharge limitations, and high energy consumption, which hinder sustainable and cost-effective manufacturing.
Innovation Solution
A closed-loop process utilizing highly concentrated transition metal nitrate solutions and alkali hydroxides for co-precipitation, with recycling of nitric acid and ammonia, reduces waste and energy consumption by recovering and reusing nitrate salts and alkali compounds, thereby minimizing environmental impact and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional co-precipitation process using sulfate salts is used, then mixed metal hydroxide precursor can be produced, but large amount of waste water containing ammonia and sodium sulfate is generated
Solution Approach 1:
The patent changes the anion parameter from sulfate to nitrate in the co-precipitation process. By using nitrate salts instead of sulfate salts, the process produces soluble nitrate byproducts that can be easily separated and recycled, avoiding the formation of insoluble sodium sulfate precipitate that complicates waste water treatment and disposal
Solution Approach 2:
The patent implements a recycling system where nitrate salts and alkali compounds from the waste water are recovered and reused in subsequent co-precipitation reactions. This closed-loop approach converts waste streams into valuable process inputs, dramatically reducing waste water discharge while maintaining continuous production
2Quantity of substance
If conventional co-precipitation process is used, then mixed metal hydroxide precursor can be produced, but high energy consumption is required for waste water treatment and ammonia removal
Solution Approach 1:
The patent changes the chemical composition parameter of the waste stream by using nitrate instead of sulfate. The resulting nitrate-containing waste water requires less intensive treatment because nitrates remain soluble and can be directly recycled, eliminating the need for energy-intensive evaporation and crystallization processes required for sodium sulfate removal
Solution Approach 2:
The recycling of nitrate salts and alkali compounds from waste water creates a closed-loop system that minimizes waste generation. By recovering and reusing these materials in-situ, the process eliminates the need for external waste treatment facilities and reduces overall energy consumption associated with waste management
3Productivity
If conventional co-precipitation process with dilute solutions is used, then precursor can be produced, but low production efficiency and high water consumption occur
Solution Approach 1:
The patent changes the concentration parameter of the feed solutions used in co-precipitation. By using highly concentrated nitrate salt solutions instead of dilute sulfate solutions, the process achieves higher precursor production rates per unit volume of water, simultaneously improving productivity and reducing water consumption
Solution Approach 2:
The recycling of nitrate salts and alkali compounds from the process water creates a closed-loop system where water is retained and reused. This dramatically reduces fresh water consumption while maintaining high production efficiency, as the concentrated solutions can be continuously fed into the reactor
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 significantly reduces waste generation, enhances production efficiency, and lowers energy consumption, making the process more sustainable and economically viable for large-scale industrial applications.
Implementation Method 1
A closed-loop process utilizing highly concentrated transition metal nitrate solutions and alkali hydroxides for co-precipitation
Implementation Method 2
with recycling of nitric acid and ammonia, reduces waste and energy consumption by recovering and reusing nitrate salts and alkali compounds
Data Source
AI summary
This invention relates to an industrial process of manufacturing hydroxide precursor for lithium transition metal oxide used in secondary lithium ion batteries. More particularly, this process utilizes highly concentrated nitrate salts and is designed to mitigate waste production.