Selective Oxidation of Lead Sulphide in Mixed Ore

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Solution Overview

Problem

Current methods for treating mixed sulphidic ores, particularly those containing lead and zinc, face challenges in selectively oxidizing lead sulphide while minimizing the oxidation of other metal sulphides, leading to inefficient separation and recovery of metals.

Innovation Solution

A process involving selective oxidation of lead sulphide to form oxidized lead compounds while limiting the oxidation of other metal sulphides, followed by flotation to separate the oxidized lead compounds from other metal sulphides, using grinding to achieve adequate mineral liberation and controlled oxidation conditions with air and sulphuric acid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If selective oxidation is applied to convert lead sulphide to oxidized lead compounds, then lead separation efficiency is improved, but other metal sulphides may also be oxidized causing contamination

Engineering Contradiction:

Improvelead separation efficiencyVSAvoidoxidation of other metal sulphides

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by controlling oxidation conditions (temperature, oxygen partial pressure, time) to selectively oxidize lead sulphide while minimizing oxidation of other metal sulphides. This resolves the contradiction by adjusting process parameters to achieve selective oxidation without excessive oxidation of zinc and copper sulphides.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs local quality by creating different chemical environments for different sulphide minerals through controlled oxidation conditions. Lead sulphide is selectively oxidized in specific local conditions (controlled oxygen exposure, temperature zones) while other sulphides remain relatively unaffected, enabling selective separation.

Inventive Principle:

Principle #3Local quality

2Productivity

If multiple flotation steps are used to separate lead and zinc concentrates, then metal recovery is improved, but process complexity increases

Engineering Contradiction:

Improvemetal recoveryVSAvoidprocess complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing selective oxidation of lead sulphide before flotation. This pre-treatment step modifies the lead sulphide to oxidized lead compounds, which then float more readily with standard collectors. This preliminary chemical modification simplifies the subsequent flotation process, reducing the number of steps needed while maintaining high recovery.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical flotation separation with a combined chemical-mechanical approach. By substituting chemical oxidation treatment before flotation, the process achieves better separation efficiency with fewer flotation stages, effectively replacing multiple mechanical separation steps with a chemical pre-treatment followed by simplified mechanical separation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If hydrometallurgical leaching with sulphuric acid is used to dissolve zinc sulphide, then zinc recovery is improved, but lead sulphide dissolution and contamination occur

Engineering Contradiction:

Improvezinc recoveryVSAvoidlead sulphide dissolution

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by separating lead (as oxidized lead compounds) from zinc sulphide through flotation before performing hydrometallurgical leaching on the zinc concentrate. This pre-separation ensures that when sulphuric acid leaching is applied to recover zinc, the lead content is already minimized, preventing lead dissolution and contamination during the zinc recovery process.

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 process effectively separates oxidized lead compounds from other metal sulphides, resulting in high lead recovery and concentration in tailings, with minimal dilution by other minerals, allowing for efficient further processing and recovery of lead and other metals.

Implementation Method 1

subjecting the mixed sulphidic material to selective oxidation such that lead sulphide in the material is oxidised to form an oxidised lead compound whilst substantial oxidation of the at least one other metal sulphide is avoided

Methodology Applied

Scientific EffectSelective oxidation: Oxidation

Implementation Method 2

The slurry is introduced into a reaction vessel and oxygen is introduced to the vessel. The sulphide is converted into substantially water insoluble oxidic lead compounds

Methodology Applied

Scientific EffectOxidation by oxygen: Oxidation

Data Source

PatentEP2742159B1Treatment of sulphidic materials

Publication Date: 2018.12.12 GLENCORE QUEENSLAND

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AI summary

A process for treating a mixed sulphidic material containing lead sulphide and at least one other metal sulphide comprises the steps of subjecting the mixed sulphidic material to selective oxidation such that lead sulphide in the material is oxidised to form an oxidised lead compound whilst substantial oxidation of the at least one other metal sulphide is avoided, and separating the oxidized lead compound from the at least one other metal sulphide. The oxidized lead compound may be separated by flotation wherein the oxidized lead compound reports to the tailings and the at least one other metal sulphide reports to the concentrate (froth).