Red Mud Metal Recovery via Roasting and Ion Exchange

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Solution Overview

Problem

The Bayer process for alumina production generates large quantities of red mud, which contains valuable metals and rare earth metals but has low concentration levels, making extraction economically unsustainable and posing environmental hazards due to inefficient disposal methods.

Innovation Solution

A multistage process involving grinding, roasting, mixing with additives to modify basicity index, melting, and subsequent separation steps using alkaline and acid leaching, followed by ion exchange resins to concentrate and separate metals and rare earth metals, utilizing waste materials like fly ash to enhance the extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If red mud is disposed of in landfill, then environmental hazards are minimized, but valuable metals and rare earth metals are lost and extraction becomes economically unsustainable

Engineering Contradiction:

Improveenvironmental hazardsVSAvoidvaluable metals and rare earth metals

Core Design Contradiction:

Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent transforms the harmful waste material (red mud) into a valuable resource by extracting metals and rare earth metals through a multi-stage process involving roasting, leaching, and ion exchange, thereby converting an environmental hazard into economic benefit

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies parameter changes by modifying the chemical and physical properties of red mud through roasting at elevated temperatures and adjusting pH levels during leaching stages to enable selective extraction of valuable metals while managing environmental impacts

Inventive Principle:

Principle #35Parameter changes

2Loss of substance

If extraction process is implemented, then valuable metals and rare earth metals are recovered, but process complexity increases due to low concentration levels

Engineering Contradiction:

Improvemetals and rare earth metals recoveryVSAvoidextraction process complexity

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The patent divides the extraction process into distinct stages: roasting, alkaline leaching, acid leaching, and ion exchange, with each stage targeting specific metals and simplifying the overall extraction by breaking down the complex low-concentration mixture into manageable separation steps

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses ion exchange resins as intermediary materials to selectively capture and concentrate specific metals and rare earth metals from the leachate, simplifying the separation process and reducing the complexity of direct extraction from low-concentration red mud

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If basicity index is not modified, then processing is simpler, but extraction efficiency decreases

Engineering Contradiction:

Improveprocessing simplicityVSAvoidextraction efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent modifies the basicity index of red mud by controlling roasting conditions and adding specific additives, thereby changing the chemical parameters to enhance metal solubility and extraction efficiency while maintaining manageable process complexity through systematic parameter optimization

Inventive Principle:

Principle #35Parameter changes

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 process effectively concentrates and separates metals and rare earth metals from red mud, enabling their industrial-scale extraction and reuse or sale, reducing waste and environmental impact while promoting a circular economy.

Implementation Method 1

roasting, in order to also eliminate the crystallization water

Methodology Applied

Scientific EffectRoasting: Heating

Implementation Method 2

melting of the material, if necessary pre-treated as indicated above, by means of any of the prior art techniques

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

subsequent separation steps using alkaline and acid leaching

Methodology Applied

Scientific EffectLeaching: Solvation

Implementation Method 4

subsequent separation steps using alkaline and acid leaching

Methodology Applied

Scientific EffectLeaching: Solvation

Implementation Method 5

followed by ion exchange resins to concentrate and separate metals and rare earth metals

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3526353B1Process for the preparation of a concentrate of metals, rare metals and rare earth metals from residues of alumina production by bayer process or from materials with a chemical composition similar to said residues, and refinement of the concentrate so obtained

Publication Date: 2022.08.31 ECOTEC TIONE IMPIANTI

AI summary

Multistage process for the preparation of a concentrate of metals, rare metals and rare earth metals from residues of alumina production by Bayer process (red mud), or from materials with a chemical composition similar to red mud, and multistage process for separating the elements of interest, transforming them into single products to be re-used in the Bayer process and/or sending them to the respective reference markets. The sole figure appended shows the simplified block diagram of the invention, in terms of its most extensive definition.