Selective Flocculation for Rare Earth Separation from Kaolinite

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Solution Overview

Problem

Current methods are inefficient in economically extracting rare earth elements from kaolinite-containing materials, which often include impurities that affect the quality of kaolin products, and there is a need for a method that can separate rare earth elements while removing impurities like titania and other minerals.

Innovation Solution

A method involving a selective flocculation process using a polyacrylamide polymer with 1-20% carboxylic groups is applied to a dispersed aqueous suspension of kaolinite and rare earth element compounds, allowing for the separation of rare earth elements into a deflocculated layer while flocculating kaolinite into a separate layer, thereby enabling the removal of impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional flotation processes are used to separate rare earth elements from kaolinite, then separation can be achieved, but the process becomes costly and complex

Engineering Contradiction:
Improveseparation efficiencyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes impurities (kaolinite and other unwanted minerals) from the rare earth element concentrate using selective flocculation. The polymer selectively binds to kaolinite particles, allowing them to be separated from the rare earth elements through simple sedimentation or filtration, thereby simplifying the overall process while maintaining high separation efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The selective flocculation polymer acts as an intermediary agent that facilitates separation between rare earth elements and kaolinite. This polymer mediator selectively attaches to kaolinite surfaces through electrostatic or adsorption interactions, enabling easy separation without requiring complex flotation machinery or multiple processing stages

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If flotation processes are used to remove impurities, then impurity removal is achieved, but the cost increases significantly

Engineering Contradiction:
Improveimpurity removal efficiencyVSAvoidprocess cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs a inexpensive flocculation polymer that can be added in small doses to achieve effective impurity removal. This consumable chemical agent replaces expensive and energy-intensive flotation processes, providing a cost-effective solution that maintains high impurity removal efficiency through simple addition and separation steps

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical and energy-intensive flotation system with a chemical flocculation process. Instead of using heavy machinery, air bubbles, and complex mechanical separation equipment, the invention uses chemical agents to induce floc formation and settling, thereby reducing both equipment costs and operational expenses while achieving equivalent or superior impurity removal

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If no separation process is applied, then the process remains simple, but rare earth elements and impurities remain mixed

Engineering Contradiction:
Improveprocess simplicityVSAvoidseparation quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary flocculation treatment to the slurry before final separation. By adding the selective polymer and allowing floc formation to occur beforehand, the rare earth elements and kaolinite are pre-grouped into separable flocs, which then settle or can be easily filtered, achieving high separation quality without requiring complex subsequent processing steps

Inventive Principle:
Principle #10Preliminary action

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 separates rare earth elements from kaolinite, reducing impurity levels and avoiding costly flotation processes, allowing for the production of high-purity rare earth compounds and improved kaolin products.

Implementation Method 1

adding to the suspension a selective flocculation polymer that facilitates separation of at least a portion of the at least one rare earth element compound from the kaolinite by flocculating the kaolinite

Methodology Applied
Scientific EffectFlocculation: Flocculation

Implementation Method 2

allowing the suspension containing the polymer to separate in a selective flocculation separator into layers including a flocculated product layer and a deflocculated layer containing the portion of the at least one rare earth element compound

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Data Source

PatentEP2846923B1Rare earth element compositions obtained from particulate material comprising kaolinite and methods for obtaining rare earth element compositions from particulate material comprising kaolinite
Publication Date: 2021.07.21 IMERYS PIGMENTS INC
  • EP2846923B1 patent drawingFigure 1

AI summary

A method for obtaining rare earth element compositions is disclosed. The method includes providing a dispersed aqueous suspension of a particulate material including at least one rare earth element compound and kaolinite. The method further includes adding to the suspension a selective flocculation polymer that facilitates separation of at least a portion of the at least one rare earth element compound from the kaolinite by flocculating the kaolinite and allowing particles of the rare earth element compound to be or remain deflocculated. The method also includes allowing the suspension containing the polymer to separate in a selective flocculation separator into layers including a flocculated product layer and a deflocculated layer containing the portion of the at least one rare earth element compound. The method further includes extracting each of the separated layers from the separator. The rare earth element compound may include La2O3, CeO2, Nd2O3, or Y2O3.