Hydratable Binder Hardening via Carbonation
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Solution Overview
Problem
Current methods for manufacturing binders that harden through carbonation require high-grade materials or costly conditions, such as elevated temperatures and pressures, which are not economically viable for widespread use, and often result in slow hardening times and insufficient strength in building materials.
Innovation Solution
A method involving the partial transformation of low-grade siliceous and calcareous precursor materials at 600 to 1200°C to create a hydratable binder that hardens through a combination of hydration and carbonation, using a Ca/Si molar ratio of 0.5 to 1.8, with a focus on dicalcium silicate and other hydratable phases, allowing for faster and stronger binding without the need for expensive precursors or curing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbonating binders use high-grade precursor materials or costly manufacturing processes, then the binder achieves sufficient strength and durability, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses low-grade siliceous and calcareous precursor materials that are inexpensive and widely available, replacing high-grade materials. These materials are transformed through partial conversion at 600-1200°C to create hydratable phases that provide sufficient strength without requiring expensive inputs
Solution Approach 2:
The patent changes the Ca/Si molar ratio parameter to range from 0.5 to 1.8 (lower than traditional Portland cement), and controls the transformation temperature at 600-1200°C to achieve partial conversion (not more than 80% by weight). These parameter changes enable the use of low-grade materials while achieving adequate binder performance
2Productivity
If carbonating binders are cured at elevated temperatures and pressures, then the hardening speed increases, but the energy consumption and manufacturing cost increase
Solution Approach 1:
The binder hardens through carbonation using CO2 from the surrounding atmosphere via diffusion, without requiring external energy input for elevated temperatures or pressures. The system serves itself by utilizing naturally available resources (atmospheric CO2, ambient temperature and pressure conditions)
Solution Approach 2:
The patent applies partial conversion (not more than 80% by weight of starting material converted) to retain some unconverted precursor material that continues to contribute to strength development over time, allowing gradual hardening without intensive initial curing conditions
3Ease of manufacture
If carbonating binders use low-grade precursor materials with partial transformation, then the manufacturing cost decreases, but the hardening time increases due to insufficient CO2 availability
Solution Approach 1:
The binder is a composite system containing hydratable phases (dicalcium silicate, lime) formed from low-grade precursors, combined with unconverted precursor material. This composite structure provides both immediate hydration strength and long-term carbonation strength, balancing speed and cost
4Productivity
If Portland cement is used for hardening through hydration, then the hardening speed is fast, but the CO2 emissions and raw material consumption increase significantly
Solution Approach 1:
The patent converts CO2, which is harmful as an emission, into a beneficial hardening agent for carbonation. By designing the binder to harden through carbonation, the previously harmful CO2 becomes the mechanism for strength development, simultaneously reducing emissions and achieving hardening
Solution Approach 2:
The patent changes the Ca/Si molar ratio to 0.5-1.8 (lower than Portland cement), reducing the amount of calcium-based materials required. This parameter change decreases both raw material consumption and associated CO2 emissions from material production, while the binder still achieves sufficient strength through combined hydration and carbonation
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 reduces energy consumption and CO2 emissions, uses less natural raw materials, and achieves comparable performance to Portland cement while providing green strength in construction materials with faster hardening and increased durability.
Implementation Method 1
a hydratable material with low calcium content obtained in a partial transformation process of low grade siliceous and calcareous precursor materials
Implementation Method 2
hardens by hydration and only after partial hydration in addition by carbonation. Transformation of the material to the final state occurs by a combined hardening through hydration and carbonation
Data Source
AI summary
A method for manufacturing a binder of a hydratable material includes providing a starting material from one or more raw materials convertible by tempering at 600 to 1200° C. into the hydratable material, tempering the starting material to provide the hydratable material containing not more than 10% by weight monocalcium silicate and at least 15% by weight hydratable phases in the form of lime and dicalcium silicate, wherein the residence time and the tempering temperature are adapted to obtain the hydratable material by converting not more than 80% by weight of the starting material, and cooling the hydratable material to provide the binder comprising the hydratable material. The binder can be mixed with water and optionally one or more of aggregate, additives, admixtures to obtain a binder paste that is placed, hydrated and carbonated to produce a building product.