Carbon-Sequestering Foamed Lightweight Soil Using MgO and CO2

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Solution Overview

Problem

Traditional foamed lightweight soils use cement as a solidification agent, leading to high cost, energy consumption, pollution, and slow strength development, limiting their practical applications in engineering projects, while existing carbon sequestration technologies do not effectively address CO2 emission reduction.

Innovation Solution

Utilize magnesium oxide (MgO) as a cementing material and carbon dioxide (CO2) as a raw material for bubble formation to prepare a carbon sequestration foamed lightweight soil, reducing cement usage and incorporating CO2 into the mixture to enhance carbon absorption and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cement is used as a solidification agent in traditional foamed lightweight soil, then the soil achieves sufficient strength and durability, but the production cost increases, energy consumption increases, and environmental pollution increases

Engineering Contradiction:

Improvesoil strengthVSAvoidenergy consumption

Core Design Contradiction:

StrengthVSUse of energy by stationary object

Solution Approach 1:

The patent changes the chemical composition parameter by replacing cement with MgO as the solidification agent. MgO undergoes carbonization reaction with CO2 to form MgCO3, providing binding strength through a different chemical mechanism than cement hydration, thereby reducing energy consumption and pollution while maintaining soil strength

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts CO2, which is typically a harmful greenhouse gas, into a beneficial resource by using it as both a foaming agent and a carbonization reactant. The CO2 bubbles provide foaming effect while the carbonization of MgO with CO2 provides solidification, turning environmental harm into dual benefits of carbon sequestration and soil strengthening

Inventive Principle:

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

2Strength

If cement is used as a solidification agent, then the soil achieves sufficient strength, but the curing time increases and construction efficiency decreases

Engineering Contradiction:

Improvesoil strengthVSAvoidcuring time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent changes the chemical reaction kinetics by using MgO carbonization instead of cement hydration. The carbonization reaction proceeds at ambient temperature and achieves sufficient strength in 3-6 hours, compared to cement's 28-day curing period, dramatically reducing construction time while maintaining strength

Inventive Principle:

Principle #35Parameter changes

3Strength

If traditional foaming agents are used to create closed bubbles in lightweight soil, then the desired bulk density and strength are achieved, but the environmental pollution and carbon emissions increase

Engineering Contradiction:

Improvesoil strengthVSAvoidenvironmental pollution

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent converts CO2 emissions from environmental harm into a useful foaming agent. The CO2 gas forms stable bubbles in the soil mixture, providing the required bulk density and strength characteristics while simultaneously sequestering carbon, thus eliminating pollution rather than generating it

Inventive Principle:

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

Solution Approach 2:

CO2 serves multiple functions simultaneously: it acts as the foaming agent to create bubbles for lightweight structure, as the carbonization reactant to strengthen MgO, and as the carbon sequestration medium. This multi-functionality eliminates the need for separate foaming agents and strengthens the environmental benefit

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The method achieves low carbon, energy-efficient production of lightweight soil with improved strength, reduced environmental impact, and enhanced carbon storage capabilities, suitable for sustainable construction projects.

Implementation Method 1

MgO carbonization technology

Methodology Applied

Scientific EffectCarbonization: Chemical Bonding

Implementation Method 2

absorption of a large amount of CO2

Methodology Applied

Scientific EffectAbsorption of CO2: Absorption (physical)

Implementation Method 3

physical, chemical or biological foaming agents

Methodology Applied

Scientific EffectFoaming: Foam

Implementation Method 4

micro-bubble clusters generated by physical, chemical or biological foaming agents

Methodology Applied

Scientific EffectBubble formation: Bubble

Data Source

PatentUS12509634B2Carbon sequestration foamed lightweight soil and preparation method thereof

Publication Date: 2025.12.30 SOUTHEAST UNIV

AI summary

The present application belongs to the technical field of civil and architectural engineering materials, and in particular relates to an environmental and low-carbon foamed lightweight soil prepared by using CO2 and MgO as raw materials. Raw material compositions of the carbon sequestration foamed lightweight soil include, in parts by weight, 10 to 200 parts of MgO, 10 to 100 parts of a filler, 2 to 45 parts of a CO2 bubble cluster and 20 to 400 parts of water. The present application is made in view of the problems of large carbon emission and serious energy consumption caused by a cement solidification agent used in traditional foamed lightweight soil.