Low-Carbon Cement Production via Pre-Calcination and Sulphate Regulation
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Solution Overview
Problem
Conventional cement production methods result in high greenhouse gas emissions and energy consumption, while also failing to effectively regulate the setting of low-carbon clinker, which is prone to instantaneous setting due to its low tri-calcium aluminate content.
Innovation Solution
A method involving the production of low-carbon cement by pre-calcining limestone, introducing silico-aluminous materials during the clinkering process, and adding calcium sulphate to regulate setting, thereby reducing energy usage and minimizing heat loss, while incorporating additional components like pozzolanic materials to enhance chemical resistance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional cement production methods are used, then high functionality is achieved, but high greenhouse gas emissions and energy consumption occur
Solution Approach 1:
Limestone is pre-calcined before the main clinkering process, performing the decomposition of calcium carbonate in advance. This preliminary action reduces the energy and emissions required during the subsequent clinkering stage, as the raw material is already partially processed and more reactive
Solution Approach 2:
The clinkering process is conducted at a reduced temperature range of 1450-1550°C compared to conventional higher temperatures. This parameter change lowers energy consumption and associated greenhouse gas emissions while still achieving the necessary clinker formation through the use of pre-calcined material and optimized composition
2Use of energy by moving object
If low-carbon clinker is produced with reduced C3A content, then energy consumption is reduced, but instantaneous setting occurs
Solution Approach 1:
Calcium sulphate is introduced as an intermediary substance that mediates between the low-C3A clinker and the setting process. It forms calcium aluminate sulphate hydrate phases that regulate the setting reaction, preventing instantaneous setting while maintaining the energy-efficient low-C3A composition
Solution Approach 2:
The chemical composition parameters are modified by adding calcium sulphate (0.1-10% by weight) and adjusting the C3A content to 5-20%. This parameter change transforms the setting behavior from instantaneous to controlled, while the pre-calcination and lower clinkering temperature maintain reduced energy consumption
3Reliability
If silico-aluminous materials are introduced during clinkering, then chemical resistance is improved, but process complexity increases
Solution Approach 1:
Silico-aluminous materials are merged with the pre-calcined raw material before clinkering. This combination integrates the chemical resistance-enhancing components into the clinker formation process itself, rather than adding them separately later, thereby improving chemical resistance without proportionally increasing process complexity
Solution Approach 2:
The silico-aluminous materials serve multiple functions: they enhance chemical resistance of the cement, contribute to the clinker mineralogy, and work synergistically with the pre-calcined limestone to achieve stable setting. This multi-functionality justifies the additional material input without requiring separate processing steps for each benefit
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 reduced energy consumption, lower greenhouse gas emissions, and maintains high functionality of the cement, with improved chemical resistance and controlled setting, allowing for efficient energy recovery from the production process.
Implementation Method 1
pre-calcination of such limestone in the raw material
Implementation Method 2
start of a clinkering process with a pre-calcined raw material
Implementation Method 3
cooling the intermediate material
Data Source
AI summary
The present invention falls within the field of building materials, particularly in the production of cement. It is specifically referred to the production of a cement which is obtained from a low-carbon clinker. The present invention provides a development in cement production with respect to the known cements, thus obtaining a cement with low greenhouse gases emissions, reducing the specific heat consumption and increasing chemical resistance, while maintaining all its functional properties.