Sulfatizing Sulfide-Free Minerals with Sulfur Trioxide Gas

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Solution Overview

Problem

Existing methods for treating sulfur-free minerals are costly and risky due to the handling of sulfuric acid, and they often result in inefficient use of acidic roasting agents and inability to separate valuable metals from impurities.

Innovation Solution

A dry process of sulfatizing sulfur-free minerals with sulfur trioxide to produce metal sulfates and oxides, avoiding the production of sulfuric acid and allowing for selective recovery of desired metals, with optional recycling of unreacted sulfur trioxide and use of various reactor types for optimal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfuric acid leaching is used to treat sulfide-free minerals, then metal separation is achieved, but production costs increase and safety risks arise from handling and transporting sulfuric acid

Engineering Contradiction:
Improvemetal separation capabilityVSAvoidproduction costs and safety risks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful sulfuric acid handling step from the process by using sulfur trioxide gas directly for sulfatization, eliminating the need to produce, transport, and handle liquid sulfuric acid while maintaining the metal separation capability through selective sulfate formation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state and chemical form of the sulfur-containing reagent from liquid sulfuric acid to gaseous sulfur trioxide, which improves safety and reduces handling costs while enabling direct sulfatization of sulfide-free minerals to achieve metal separation

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If acidic roasting agents are used for sulfatization, then metal sulfates are formed, but the roasting agent is only partially utilized resulting in high consumption

Engineering Contradiction:
Improvemetal sulfate formationVSAvoidacidic roasting agent consumption
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent implements continuous sulfatization by maintaining a steady flow of sulfur trioxide gas through the roasted ore, ensuring complete utilization of the roasting agent for sulfate formation and eliminating partial utilization losses associated with batch processing

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent uses sulfur trioxide gas as an intermediary that can be precisely dosed and completely consumed in the sulfatization reaction, replacing acidic roasting agents that are partially utilized and require excessive consumption to achieve complete metal sulfate formation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional leaching methods are used, then metals are separated from ore, but significant wastewater problems occur

Engineering Contradiction:
Improvemetal separation efficiencyVSAvoidwastewater generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the wet leaching mechanism with a dry sulfatization process using sulfur trioxide gas, which forms metal sulfates that can be separated without generating significant wastewater, thereby maintaining metal separation efficiency while eliminating wastewater problems

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

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 reduces production costs and risks associated with sulfuric acid handling, enhances the efficiency of metal recovery by allowing selective separation of desired metals, and improves the yield of metal oxides and sulfates, while minimizing waste.

Implementation Method 1

contacting the sulfide-free ore and/or concentrate with gaseous sulfur trioxide (SO3) for sulfatizing the sulfide-free mineral(s) thereby forming metal sulfate(s) and metal oxide(s)

Methodology Applied
Scientific EffectSulfatization: Chemical Bonding

Data Source

PatentEP3080315B1Method for treating sulfide-free minerals
Publication Date: 2019.07.03 OUTOTEC FINDLAND OY
  • EP3080315B1 patent drawingFigure 1
  • EP3080315B1 patent drawingFigure 2
  • EP3080315B1 patent drawingFigure 3

AI summary

The present invention provides a method of producing metal oxide(s) by sulfatizing a sulfide-free ore and/or concentrate comprising the steps of providing a sulfide-free ore and/or concentrate comprising sulfide-free mineral(s); and contacting the sulfide-free ore and/or concentrate with gaseous SO3 for sulfatizing the sulfide-free mineral(s) thereby forming metal sulfate(s) and metal oxide(s).