Amorphous Low-Calcium Silicate Binder Production
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Solution Overview
Problem
The cement industry faces significant CO2 emissions due to the high-temperature clinkerization process and use of limestone in conventional Portland Cement production, necessitating a method to reduce ecological footprint while maintaining technical, economic, and workability qualities.
Innovation Solution
A method involving specific heating and cooling operations within the CaO-SiO2 equilibrium diagram to produce a hydraulic binder comprising an amorphous calcium silicate phase with embedded residual wollastonite, which is fully amorphous or contains up to 20% wollastonite, utilizing common raw materials and grinding to achieve high compressive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional clinkerization process at high temperature (1450°C) using limestone is used to produce Portland Cement, then hydraulic activity and strength are achieved, but CO2 emissions increase significantly
Solution Approach 1:
The patent changes the chemical composition parameters by using a raw meal with CaO:SiO2 ratio between 0.8:1 and 1.2:1 (deviating from conventional high-calcium composition) and controls the cooling rate (200-500°C/min) to produce an amorphous calcium silicate phase instead of crystalline clinker phases, thereby reducing CO2 emissions while maintaining hydraulic activity
Solution Approach 2:
The patent utilizes phase transition by rapidly cooling the heated raw meal from high temperature to produce an amorphous phase (glassy structure) instead of crystalline phases. This phase transition creates a material with latent hydraulic activity that activates upon contact with water, forming C-S-H gel without requiring high-temperature clinkerization
2Strength
If high-temperature clinkerization (1450°C) is used to produce alite (C3S) for good hydraulic behavior, then strength is improved, but energy consumption and CO2 emissions increase
Solution Approach 1:
The patent extracts the essential hydraulic function from the conventional clinkerization process by producing an amorphous calcium silicate phase that provides latent hydraulic activity without requiring the formation of alite crystals through high-temperature processing, thereby eliminating the need for energy-intensive clinkerization
Solution Approach 2:
The patent uses a simplified process that avoids the expensive and energy-intensive clinkerization step by directly producing an amorphous phase from raw materials that can be activated with water, effectively replacing the conventional multi-step high-temperature process with a lower-energy alternative
3Stability of the object's composition
If limestone is used as the source of calcium in conventional cement production, then hydraulic binder properties are achieved, but CO2 emissions from decarbonation increase by approximately 60% of total emissions
Solution Approach 1:
The patent changes the chemical composition by controlling the CaO:SiO2 ratio to be between 0.8:1 and 1.2:1, which is lower than conventional cement compositions. This parameter change allows the formation of an amorphous calcium silicate phase that provides hydraulic activity without requiring the decarbonation of limestone, thereby reducing CO2 emissions from this source
4Object-generated harmful factors
If rapid cooling (200-500°C/min) is applied to produce amorphous phase, then CO2 emissions are reduced, but manufacturing process complexity increases
Solution Approach 1:
The patent utilizes rapid cooling to induce phase transition from crystalline to amorphous state. The specified cooling rate range (200-500°C/min) is optimized to achieve complete amorphization while maintaining process simplicity, allowing the use of conventional cooling equipment with proper control parameters
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 CO2 emissions while achieving compressive strengths comparable to or exceeding traditional cement, with the amorphous calcium silicate phase hydrating to form tobermorite-like structures without portlandite formation, enhancing durability and reducing permeability.
Implementation Method 1
the amorphous calcium silicate phase hydrating to form tobermorite-like structures without portlandite formation
Implementation Method 2
The hydraulic binder is produced by a combination of heating and cooling operations
Data Source
Figure 1a
Figure 1b
Figure 1c~1d
AI summary
The invention relates to a hydraulic binder consisting essentially in a hydraulically active amorphous calcium silicate phase, having in its constitution less than 20% in weight of a crystalline material. The said hydraulically active amorphous calcium silicate phase is a continuous matrix that may contain embedded fractions of crystalline material, being the overall C/S molar ratio of this hydraulic binder comprised between 0.8 and 1.25. The crystalline fraction of this material is essentially composed by wollastonite in both of its polymorphic structures, a and β. Furthermore,, the invention relates to methods of producing the hydraulic binder by liquefying the raw materials, in a specified C/S molar ratio, followed by fast cooling to room temperature. Finally, the invention relates to a building material made by setting the binder or a mixture containing this binder with water and subsequent hardening. The invention enables the production of a hydraulic binder with a significant reduction of C02 emissions, when compared to OPC clinker, by reducing the amount of limestone in the raw materials while obtaining competitive overall values of compressive strength of the hardened material.