Low Calcium Cement Hardening via Mullite Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional alkali-activated cements made from low calcium fly ash cannot harden at room temperature due to low calcium oxide content, and ordinary portland cement lacks acid and fire resistance, limiting its use in certain environments.
Innovation Solution
A low-calcium cementitious material composed of low calcium fly ash, an alkaline agent, and a congealing agent, with a calcium oxide content ≤10 wt%, that hardens at room temperature to form mullite (Al6Si2O13), using sodium hydroxide and sodium fluosilicate, and optionally silicofluoride, accelerators, and drainage agents, without requiring additional calcium-containing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low calcium fly ash is used to make cement, then acid and fire resistance is improved, but the material cannot harden at room temperature
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific alkaline agents (sodium hydroxide, sodium silicate) and congealing agents (calcium carbonate, magnesium oxide) to enable room temperature hardening of low calcium fly ash cement while maintaining its low calcium oxide content (≤10 wt%) for acid and fire resistance
Solution Approach 2:
The patent creates a composite material system combining low calcium fly ash with alkaline agents and congealing agents, forming a multi-component cementitious material that achieves both room temperature hardening and environmental resistance properties
2Ease of manufacture
If ordinary portland cement is used, then ease of manufacture is improved, but acid and fire resistance deteriorates
Solution Approach 1:
The patent reduces the calcium oxide content parameter to ≤10 wt% (compared to ordinary portland cement which typically has 60-65% CaO), fundamentally changing the material's chemical composition to achieve superior acid and fire resistance while maintaining manufacturability through the addition of alkaline and congealing agents
3Ease of manufacture
If additional calcium-containing materials are added to low calcium fly ash, then room temperature hardening is improved, but calcium oxide content increases reducing acid and fire resistance
Solution Approach 1:
The patent applies local quality by introducing calcium-containing congealing agents (calcium carbonate, magnesium oxide) in controlled, localized amounts specifically to enable hardening, while maintaining the overall low calcium oxide content (≤10 wt%) of the fly ash matrix to preserve acid and fire resistance properties
Solution Approach 2:
The patent precisely controls the calcium oxide content parameter at ≤10 wt% by carefully dosing congealing agents, achieving room temperature hardening capability without significantly increasing the overall calcium content that would compromise environmental resistance
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
Enables the production of low calcium cement with improved acid and fire resistance, allowing its use in acidic and high-temperature environments without the need for additional coatings, increasing the economic value of low calcium fly ash and enhancing its environmental sustainability.
Implementation Method 1
low calcium fly ash, an alkaline agent, and a congealing agent... hardens at room temperature to form mullite (Al6Si2O13)
Data Source
AI summary
A low-calcium-cementitious material having a calcium oxide content less than or equal to 10 wt % which is processed at room temperature into a low calcium cement mainly composed of mullite and a method manufacturing of the low calcium cement are provided. The low-calcium-cementitious material includes low calcium fly ash, an alkaline agent, and a congealing agent, wherein the calcium oxide content of the low-calcium-cementitious material is less than or equal to 10 wt %. The low calcium fly ash has a calcium oxide content less than or equal to 10 wt %. The low calcium cement manufacturing method includes providing a low calcium fly ash having a calcium oxide content less than or equal to 10 wt %; providing an alkaline agent; providing a congealing agent; and mixing the low-calcium-content fly ash, the alkaline agent, and the congealing agent and standing the mixture at room temperature to form a low calcium cement.