Sulfide Mine Waste Stabilization via CO2 Carbonation

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Solution Overview

Problem

Mining activities lead to Acid Rock Drainage (ARD), contaminating waterways and groundwater due to the oxidation of sulfide minerals, which is costly and environmentally damaging, and current mitigation methods are expensive and require long-term maintenance.

Innovation Solution

A process using a CO2-enriched gas mixture to react with sulfide-rich mine waste, converting sulfide minerals into chemically stable forms while sequestering CO2, thereby reducing ARD and metal leaching, and producing valuable reaction products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If sulfide minerals are exposed to air and water during mining activities, then metal extraction is enabled, but Acid Rock Drainage contaminates waterways and groundwater

Engineering Contradiction:

Improvemetal extractionVSAvoidAcid Rock Drainage

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful oxidation reaction that causes ARD into a beneficial process by introducing CO2-enriched gas to react with sulfide minerals, transforming the harmful sulfuric acid production into useful carbonate mineral formation that sequesters CO2 and stabilizes the waste material

Inventive Principle:

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

Solution Approach 2:

The invention changes the chemical parameters of the oxidation environment by replacing air (oxygen-rich) with CO2-enriched gas, fundamentally altering the reaction pathway from harmful sulfuric acid formation to beneficial carbonate mineral formation while maintaining the metal extraction capability

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If conventional ARD mitigation methods are implemented, then environmental contamination is reduced, but costs increase and long-term maintenance is required

Engineering Contradiction:

Improveenvironmental contaminationVSAvoidmitigation system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention enables the mine waste to treat itself by reacting with CO2-enriched gas to form stable carbonate minerals, eliminating the need for external mitigation infrastructure and long-term maintenance while achieving environmental protection

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention transforms the discarded harmful sulfide waste into valuable stable carbonate minerals that sequester CO2, converting a liability into an asset while eliminating the need for complex mitigation systems

Inventive Principle:

Principle #34Discarding and recovering

3Object-affected harmful factors

If sulfide minerals are left unprocessed in waste rock piles, then ARD risk is reduced, but valuable metals remain trapped and CO2 emissions increase from mining operations

Engineering Contradiction:

ImproveARD riskVSAvoidvaluable metals

Core Design Contradiction:

Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The invention performs preliminary stabilization of sulfide minerals by reacting them with CO2-enriched gas to form stable carbonate minerals before they can generate ARD, enabling subsequent safe processing or disposal while recovering valuable metals and sequestering CO2

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 stabilizes sulfide minerals, reduces ARD and metal leaching, sequesters CO2, and generates valuable products, improving environmental and economic outcomes for mining sites and reducing greenhouse gas emissions.

Implementation Method 1

A process using a CO2-enriched gas mixture to react with sulfide-rich mine waste, converting sulfide minerals into chemically stable forms while sequestering CO2

Methodology Applied

Scientific EffectCarbonation reaction: Chemical Bonding

Implementation Method 2

converting sulfide minerals into chemically stable forms while sequestering CO2, thereby reducing ARD and metal leaching

Methodology Applied

Scientific EffectCO2 sequestration: Absorption (physical)

Data Source

PatentUS9284621B2Processing of sulfate and/or sulfide-rich waste using CO<sub>2</sub>-enriched gases to sequester CO<sub>2</sub>, reduce environmental impacts including acid rock drainage and produce reaction products

Publication Date: 2016.03.15 TERRA CO2 TECHNOLOGY HOLDINGS INC

AI summary

A process is provided for stabilizing a sulfate and/or sulfide-rich waste material, comprising metal sulfide minerals, and sequestering CO2 comprises exposing the material to a CO2-enriched gas mixture, reacting the CO2-enriched gas mixture with the metal sulfide minerals and forming a CO2-depleted gas mixture and a carbon-containing compound and at least one product selected from the group consisting of a purified metal or a metal-rich compound suitable for smelting or refining, sulfuric acid, sulfur and sulfurous acid, and system and apparatus therefor.