Sequential Clay Adsorption for Rare Earth Recovery
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Solution Overview
Problem
Current methods for treating wastewater containing rare earth elements and ammonia nitrogen are inefficient, leading to environmental pollution and resource waste, as they struggle with low concentration processing, high costs, and secondary pollution, particularly in rare earth mining and industrial processes.
Innovation Solution
A sequential adsorption method using fine-grained and coarse-grained clay, where fine-grained clay with a grain diameter of 1-250 μm and coarse-grained clay with a grain diameter of 150-1,000 μm are used to adsorb and desorb rare earth, accompanied by pH regulation and bipolar membrane electrodialysis to reduce ammonia nitrogen concentrations, facilitating efficient recycling and solid-liquid separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional treatment methods are used for wastewater containing rare earth elements, then the treatment process is simple, but the treatment efficiency is low and secondary pollution occurs
Solution Approach 1:
The patent segments the treatment process into multiple stages: preliminary treatment, adsorption treatment, and advanced treatment. Each stage uses different treatment methods tailored to specific contamination levels and types, improving overall efficiency while preventing secondary pollution through controlled treatment progression.
Solution Approach 2:
The patent employs parameter changes by adjusting pH values, contact times, and dosages of treatment agents dynamically during the treatment process. This allows optimization of treatment efficiency at different stages while controlling harmful byproducts through precise parameter management.
2Quantity of substance
If existing adsorption methods are used, then the process is cost-effective, but it cannot effectively handle low concentration rare earth solutions
Solution Approach 1:
The patent segments the adsorption process into two stages: first stage uses conventional adsorption for high concentration solutions, second stage uses enhanced adsorption with modified conditions for low concentration solutions. This segmentation allows effective handling of both high and low concentration streams simultaneously.
Solution Approach 2:
The patent employs composite adsorbent materials combining different adsorption mechanisms and affinities. The composite structure enables effective adsorption across a wide concentration range, improving both removal capacity and processing efficiency for diverse wastewater compositions.
3Object-affected harmful factors
If comprehensive treatment is implemented to meet discharge standards, then environmental protection is improved, but treatment cost increases
Solution Approach 1:
The patent segments the treatment process into prioritized stages, applying comprehensive treatment only where necessary. By identifying and treating the most harmful contaminants first through cost-effective methods, and reserving expensive treatments for residual contamination, the system achieves discharge standards while minimizing overall treatment cost.
Solution Approach 2:
The patent implements self-service through the generation and reuse of acidic and alkaline solutions during the treatment process. These byproducts are recycled back into the treatment system, reducing the need for external chemical additives and lowering operational costs while maintaining treatment effectiveness.
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 effectively reduces rare earth concentrations to below 1 mg/L and ammonia nitrogen to safe levels, enabling efficient recycling and cost reduction while meeting stringent wastewater discharge standards, thus conserving resources and protecting the environment.
Implementation Method 1
performing a fine-grained clay adsorption on the solution containing rare earth with fine-grained clay; performing a coarse-grained clay adsorption on the solution adsorbed by the fine-grained clay with coarse-grained clay
Implementation Method 2
bipolar membrane electrodialysis to reduce ammonia nitrogen concentrations
Implementation Method 3
accompanied by pH regulation
Data Source
AI summary
The present invention provides a treating method for a solution containing rare earth, wherein the method comprising: (1) performing a fine-grained clay adsorption on the solution containing rare earth with fine-grained clay, the conditions of the fine-grained clay adsorption allow that solution adsorbed by said fine-grained clay contains rare earth with a concentration calculated by rare earth oxides not higher than 1 mg/L; (2) performing a coarse-grained clay adsorption on the solution adsorbed by said fine-grained clay with coarse-grained clay, the conditions of coarse-grained clay adsorption allow that solution adsorbed by said coarse-grained clay contains rare earth with a concentration calculated by rare earth oxides not higher than 0.5 mg/L; the grain diameter of at least 90% of said fine-grained clay particles is smaller than the grain diameter of said coarse-grained clay particles, and the grain diameter of said fine-grained clay is within a range of 1-250 μm, and the grain diameter of said coarse-grained clay is within a range of 150-1,000 μm; and (3) desorbing rare earth from said fine-grained clay undergone the fine-grained clay adsorption and said coarse-grained clay undergone the coarse-grained clay adsorption. The rare earth may be effectively recycled by applying the above method.