Sulfidic Copper Concentrate Refining via Segmented Smelting

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Solution Overview

Problem

The direct-to-blister process for refining sulfidic copper concentrate faces challenges such as high thermal energy production, non-uniform blister copper composition, high impurity content, and inefficient copper recovery from slag, particularly when treating low-grade concentrates.

Innovation Solution

The method involves using sulfidic copper concentrate as a reducing agent in the electric furnace, where it reacts with unreduced slag to form immiscible copper matte and slag products, reducing process gases and impurities, and feeding the solidified matte back into the blister furnace for uniform blister copper production, thereby reducing impurities and energy requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If sulfidic copper concentrate is treated in a suspension smelting furnace to produce blister copper, then copper production is achieved, but thermal energy production is excessive requiring large capacity process gas treatment arrangements

Engineering Contradiction:
Improvecopper productionVSAvoidprocess gases
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent divides the copper concentrate treatment into two separate stages: (1) suspension smelting furnace for producing blister copper, and (2) electric furnace for treating a portion of the concentrate to produce reduced slag. This segmentation allows process gases to be generated in controlled amounts at different stages, making gas treatment more manageable while maintaining overall copper production efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the chemical parameters of the slag by introducing a reducing agent (coke or natural gas) in the electric furnace, transforming unreduced slag into reduced slag with different chemical composition. This parameter change reduces the oxygen content and alters the slag's reactivity, thereby reducing the amount of process gases requiring treatment in the suspension smelting furnace.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional direct-to-blister process is used, then blister copper is produced, but the composition is non-uniform with high impurity content such as arsenic

Engineering Contradiction:
Improveblister copper productionVSAvoidblister copper composition uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the copper concentrate feed into two streams: one for the suspension smelting furnace and another for the electric furnace. The electric furnace produces reduced slag with lower impurity content that is then fed back to the suspension smelting furnace. This segmented approach ensures more uniform composition and lower impurity levels in the final blister copper product.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary reduction of copper concentrate in the electric furnace before feeding the reduced material to the suspension smelting furnace. This preliminary action removes impurities and adjusts the chemical composition in advance, ensuring that the material entering the main smelting process has more uniform properties and lower impurity content.

Inventive Principle:
Principle #10Preliminary action

3Loss of substance

If flotation is used to recover copper from electric furnace slag, then copper recovery is attempted, but it is inefficient because copper in slag is mostly not in sulfidic form

Engineering Contradiction:
Improvecopper recoveryVSAvoidcopper recovery difficulty
Core Design Contradiction:
Loss of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the slag by introducing a reducing agent in the electric furnace, which transforms the copper compounds in the slag into sulfidic form. This parameter change makes the copper in the slag amenable to flotation recovery, significantly improving copper recovery efficiency from the slag material.

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

This approach results in a more efficient process with reduced thermal energy demand, uniform blister copper composition, lower impurity levels, and improved copper recovery from slag, particularly through flotation due to the sulfidic form of copper in the slag.

Implementation Method 1

reducing the slag (7) fed in unreduced state from the suspension smelting furnace (5) into the electric furnace (12) with sulfidic copper concentrate (1)

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

A problem with the direct-to-blister process when treating concentrates with low copper grade is that it produces a lot of thermal energy

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Implementation Method 3

improved copper recovery from slag, particularly through flotation due to the sulfidic form of copper in the slag

Methodology Applied
Scientific EffectFlotation: Froth Floatation

Data Source

PatentEP3488021B1Method for refining sulfidic copper concentrate
Publication Date: 2020.06.17 OUTOTEC FINDLAND OY
  • EP3488021B1 patent drawingFigure 1
  • EP3488021B1 patent drawingFigure 2
  • EP3488021B1 patent drawingFigure 3

AI summary

The invention relates to a method for refining sulfidic copper concentrate (1). The method comprises feeding sulfidic copper concentrate (1) and oxygen- bearing reaction gas (2) and slag forming material (3) into a reaction shaft (4) of a suspension smelting furnace (5), collecting slag (7) and blister copper (8) in a settler (9) of the suspension smelting furnace (5) to form a blister layer (10) containing blister copper (8) and a slag layer (11), and discharging slag (7) and blister copper (8) separately from the settler (9) of the suspension smelting furnace (5), so that slag (7) is fed into an electric furnace (12). The method comprises by feeding a part of the sulfidic copper concentrate (1) into the electric furnace (12).