Ultralow-carbon Clinker-free Cement Hydration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The cement industry in China faces a contradiction between carbon emissions and strength development, as the production of supersulfated cement has been hindered by the poor reactivity of granulated blast-furnace slag due to changes in its chemical composition, leading to difficulties in producing cement with desired technical properties.
Innovation Solution
An ultralow-carbon clinker-free cement is developed using granulated blast-furnace slag, gypsum, and a calcium oxide-based material, with a controlled weight percentage of calcium oxide and/or calcium hydroxide, along with cement additives and controlling and accelerating components, to optimize the hydration reaction and strength development, while minimizing carbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If granulated blast-furnace slag is used as the main raw material for supersulfated cement, then carbon emissions are reduced, but the reactivity of the slag deteriorates due to changes in chemical composition
Solution Approach 1:
The patent changes the chemical parameters of the system by introducing calcium oxide-based materials (quicklime, slaked lime, carbide slag) with specific CaO contents (30%-80%) to alter the reactivity characteristics of the granulated blast-furnace slag. This allows the use of slag with varying compositions while maintaining cement performance through parameter adjustment rather than relying solely on slag quality
Solution Approach 2:
The calcium oxide-based material acts as an intermediary substance that mediates between the granulated blast-furnace slag and the hydration process. It provides the necessary alkaline environment and reactive calcium ions to activate the slag, compensating for the slag's reduced inherent reactivity due to compositional changes
2Ease of manufacture
If the chemical composition of granulated blast-furnace slag changes due to ironmaking process development, then production cost may be reduced, but the strength development of cement deteriorates
Solution Approach 1:
The patent adjusts the chemical composition parameters of the cement system by adding calcium oxide-based materials with controlled CaO content (0.05%-0.75% in final cement). This compensates for the reduced reactivity of modern blast-furnace slag while maintaining production efficiency and cost-effectiveness
Solution Approach 2:
The patent creates a composite cement system combining granulated blast-furnace slag with calcium oxide-based materials and gypsum. This composite approach leverages the low-cost, abundant slag resource while using the calcium oxide-based additives to restore and enhance strength development properties
3Reliability
If calcium oxide-based material is added to activate granulated blast-furnace slag, then reactivity is improved, but the complexity of raw material composition increases
Solution Approach 1:
The patent employs readily available, low-cost calcium oxide-based materials (quicklime, slaked lime, carbide slag) that are inexpensive and easily obtained. These materials serve their activation function effectively without requiring complex processing or long-term storage, simplifying the overall system despite adding a raw material component
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 solution achieves high early strength and ultrahigh long-term strength, low shrinkage, carbonation resistance, and reduced carbon emissions, effectively addressing the industry's challenges by controlling the calcium oxide content and using appropriate activators to enhance the reactivity of granulated blast-furnace slag.
Implementation Method 1
a calcium oxide-based material... to optimize the hydration reaction and strength development
Implementation Method 2
The free calcium oxide quickly releases a proper amount of Ca2+ and OH-
Implementation Method 3
the granulated blast-furnace slag reacts with the gypsum to generate micro-expansive ettringite
Data Source
AI summary
The disclosure provides an ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum and calcium oxide-based materials. The granulated blast-furnace slag accounts for 65%-95% of the total weight of the raw materials, the gypsum accounts for 4.5%-34.5% of the total weight of the raw materials, and the balance is the calcium oxide-based material. A weight percentage of calcium oxide and/or calcium hydroxide in the total weight of the raw materials is controlled to be 0.05%-0.75%. The disclosure further provides a method for preparing the ultralow-carbon clinker-free cement and application of the ultralow-carbon clinker-free cement in the preparation of concrete, mortar or cement products. The ultralow-carbon clinker-free cement of the disclosure has the advantages of high early strength, ultrahigh long-term strength, low shrinkage, carbonation resistance, low carbon emissions, etc.