Iron Ore Concentrates from Copper Slag via SO2 Leaching

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Solution Overview

Problem

Current methods for preparing iron ore concentrates from copper slag tailings are costly and inefficient due to high energy consumption, complex processes, and the inability to effectively separate fayalite from magnetite at low costs using conventional magnetic separation processes.

Innovation Solution

A method involving low-concentration SO2 flue gas acid leaching and magnetic separation, where copper slag tailings are treated to leach out Fe, Cu, Zn, and Mn, followed by purification and magnetic separation to produce iron ore concentrates, utilizing a simple process that reduces costs and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional magnetic separation process is used to separate fayalite from magnetite, then separation can be performed, but separation efficiency is low and cost is high due to the need for reduction roasting and high temperature processing

Engineering Contradiction:
Improveseparation efficiencyVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the tailings by adding fluxes (lime, soda ash, borax) to modify the melting point and chemical reactivity of the matrix, enabling effective magnetic separation at lower temperatures without reduction roasting. This parameter change resolves the contradiction by achieving good separation efficiency while reducing energy consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces fluxes as intermediary substances that facilitate the separation process. These fluxes act as mediators between the magnetic minerals and the separation equipment, lowering the melting point of the tailings matrix and enabling magnetic separation to work effectively without high-temperature reduction roasting, thus reducing energy consumption while maintaining separation efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If high-temperature reduction roasting and magnetic separation are conducted, then fayalite and magnetite can be separated, but processing cost increases due to high energy consumption and complex process

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

Solution Approach 1:

The patent performs preliminary chemical preparation by adding fluxes and performing sintering before magnetic separation. This preliminary action modifies the tailings properties in advance, making them suitable for magnetic separation at lower temperatures and simplifying the overall process by eliminating the need for high-temperature reduction roasting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical and physical parameters of the tailings through flux addition and controlled sintering, transforming the refractory matrix into a more separable form. This parameter change enables effective magnetic separation with simpler equipment and lower energy input, resolving the contradiction between separation efficiency and process complexity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If copper slag tailings are directly used as iron smelting raw material, then processing is simplified, but product quality is poor and valuable metals are wasted

Engineering Contradiction:
Improveprocess simplicityVSAvoidproduct quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts valuable metals (copper, zinc, lead, arsenic) from the copper slag tailings through selective leaching and precipitation processes before using the remaining material for iron production. This extraction of impurities and valuable metals improves the quality of the final iron product while preventing waste of recoverable resources, resolving the contradiction between process simplicity and product quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the processing into distinct stages: chemical leaching to remove valuable metals, flux addition and sintering to prepare the matrix, and magnetic separation to concentrate iron minerals. This segmentation allows each stage to be optimized independently, achieving both reasonable process complexity and high product quality.

Inventive Principle:
Principle #1Segmentation

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 efficiently recovers iron ore concentrates with high purity, reduces slag tailings by 30%, and integrates acid leaching and recycling, achieving economic and environmental benefits by using low-concentration SO2, thereby simplifying the process and lowering energy consumption.

Implementation Method 1

low-concentration SO2 flue gas acid leaching... leach out Fe, Cu, Zn, and Mn

Methodology Applied
Scientific EffectAcid leaching: Solvation

Implementation Method 2

magnetic separation to produce iron ore concentrates

Methodology Applied
Scientific EffectMagnetic separation: Magnetism

Data Source

PatentUS11293076B2Method for preparing iron ore concentrates by recycling copper slag tailings
Publication Date: 2022.04.05 KUNMING UNIV OF SCI & TECH

AI summary

The present invention discloses a method for preparing iron ore concentrates by recycling copper smelting slag tailings, and belongs to the technical field of metallurgy and tailings recycling. In the present invention, copper slag tailings obtained after copper pyrometallurgy and flotation and water are used as raw materials, and low-concentration sulfur dioxide flue gas is used as a leaching agent for leaching of metals such as iron, zinc, copper, arsenic, and silicon in the slag tailings; the leachate is purified step by step through processes such as replacement by metal iron powder and sulfide precipitation control, to separate zinc, copper, arsenic, etc.; a purified solution is mainly composed of FeSO4 or can be used for producing a ferric salt flocculant; obtained tailings are used to obtain iron ore concentrates through magnetic separation, and the obtained iron ore concentrates can be used for further producing ultra-pure iron ore concentrates.