Carbonatable Calcium Silicate Compositions for CO2 Sequestration
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Solution Overview
Problem
The cement industry faces significant energy intensity and CO2 emissions, with conventional Portland cement production being energy-intensive and contributing substantially to global greenhouse gas emissions, necessitating a revolutionary approach to reduce energy requirements and emissions while allowing for CO2 sequestration.
Innovation Solution
Development of novel carbonatable calcium silicate compositions that can harden through a carbonation process, using widely available low-cost raw materials, suitable for large-scale production and adaptable to conventional cement manufacturing facilities, with a blend of discrete calcium silicate phases and an amorphous phase capable of forming CaCO3 with a mass gain of 10% or more at temperatures between 30°C to 90°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional Portland cement is used for construction, then the required strength and structural properties are achieved, but energy consumption increases and CO2 emissions are generated
Solution Approach 1:
The invention captures CO2 emissions and uses them as a reactant in the carbonation process of calcium silicate compositions. The CO2 that would normally be harmful is converted into beneficial calcium carbonate, creating strength while sequestering carbon. This is achieved by exposing the calcium silicate-based concrete to CO2 pressure, forming calcium carbonate minerals that provide structural strength.
Solution Approach 2:
The invention changes the chemical composition parameters by using calcium silicate compositions with specific Ca/Si ratios (0.8-1.2) and controlled metal oxide content (Al, Fe, Mg ≤30%). These parameter changes enable the material to react with CO2 to form calcium carbonate, transforming the cementation mechanism from hydraulic setting to carbonation hardening, thereby reducing the need for high-temperature clinker production.
2Productivity
If Portland cement manufacturing is scaled up to meet growing demand, then cement production volume increases, but energy consumption and CO2 emissions increase proportionally
Solution Approach 1:
The invention converts CO2 emissions into a useful resource for concrete hardening. By using CO2 pressure to carbonate the calcium silicate composition, the process transforms waste CO2 into calcium carbonate, which provides structural strength. This eliminates the need for energy-intensive clinker production while maintaining productivity.
Solution Approach 2:
The calcium silicate composition self-hardens through carbonation when exposed to CO2, eliminating the need for high-temperature firing required for Portland cement. The material undergoes spontaneous chemical reaction with CO2 to form calcium carbonate, providing strength without external energy input for curing.
3Productivity
If Portland cement is used to meet infrastructure demands, then construction and infrastructure projects can be completed, but significant CO2 emissions are released
Solution Approach 1:
The invention captures CO2 emissions and uses them as a reactant in the carbonation process. The CO2 that would normally contribute to greenhouse gas emissions is converted into calcium carbonate minerals that provide structural strength in concrete, simultaneously achieving construction output and carbon sequestration.
Solution Approach 2:
The invention uses composite calcium silicate compositions containing multiple phases (wollastonite, pseudowollastonite, rankinite, belite, larnite, bredigite) that work together to enable efficient carbonation. This composite approach allows the material to react with CO2 to form calcium carbonate while maintaining workability and strength development.
4Quantity of substance
If calcium silicate compositions are carbonated to form CaCO3, then CO2 sequestration is achieved with mass gain of 10% or more, but the process requires specific temperature control between 30°C to 90°C
Solution Approach 1:
The invention optimizes the Ca/Si ratio parameter (0.8-1.2) and controls metal oxide content to enable carbonation at moderate temperatures (30°C-90°C). These parameter changes allow the calcium silicate composition to react efficiently with CO2 across a wide temperature range, achieving mass gain of 10% or more while providing flexibility in processing conditions.
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 significantly reduces energy consumption and CO2 emissions, enabling permanent and safe CO2 sequestration, and is applicable in various concrete applications such as construction, pavements, and infrastructure, offering a more desirable carbon footprint.
Implementation Method 1
Each of these calcium silicate phases is suitable for carbonation with CO2 and the composition is suitable for carbonation with CO2 at a temperature of 30°C to 90°C to form CaCO3 with a mass gain of 10% or more
Data Source
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AI summary
The invention provides novel carbonatable calcium silicate compositions and carbonatable calcium silicate phases that are made from widely available, low cost raw materials by a process suitable for large-scale production. The method of the invention is flexible in equipment and production requirements and is readily adaptable to manufacturing facilities of conventional cement. The invention offers an exceptional capability to permanently and safely sequesters CO2.