Calcium Oxide Hydration Onset Delay via Organic Surface Complexes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The rapid and intense hydration reaction of calcium oxide in cement compositions is difficult to control, limiting its applications due to a drastic exothermic profile, and existing retarders only slow down the hydration without controlling the onset.
Innovation Solution
Heating precursor alkaline earth metal oxide particles, comprising 40-100% calcium oxide or a mixture with magnesium oxide, in the presence of carbohydrates or amino-carboxylic acids within a specific temperature range (200°C-700°C) to delay the hydration onset when mixed with water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional retarders are used to postpone hydration, then the hydration reaction is slowed down, but the onset of hydration cannot be controlled and the overall exothermic profile is attenuated
Solution Approach 1:
The patent changes the chemical parameters of the system by introducing specific organic materials (carbohydrates, amino-carboxylic acids) that form surface complexes with calcium oxide. This chemical modification alters the hydration kinetics, enabling both delayed onset and controlled exothermic profile without attenuating the overall reaction energy
Solution Approach 2:
The organic materials act as intermediaries between calcium oxide and water, forming surface complexes that control the hydration process. These intermediaries delay the onset of hydration by blocking water access to calcium oxide surfaces, while ultimately allowing the reaction to proceed with controlled heat release
2Adaptability or versatility
If quicklime is used as an expansive agent in cement, then expansion capability is provided, but the rapid and intense hydration reaction limits applications due to difficult control
Solution Approach 1:
The patent applies preliminary action by pre-treating calcium oxide with organic materials before use in cement compositions. This pre-treatment creates a surface complex that delays hydration onset, allowing the material to be handled and placed without premature reaction, thus improving ease of operation while maintaining expansion capability
3Reliability
If calcium oxide is heated at very high temperatures around 1400°C to attenuate hydration reaction, then the hydration profile is softened, but manufacturing of hard-burned quicklime is difficult and few products are commercially available
Solution Approach 1:
The patent changes the temperature parameter from very high (1400°C) to moderate ranges (200-700°C), achieving the same hydration control effect through chemical modification rather than thermal treatment alone. This dramatically simplifies manufacturing while maintaining reliable hydration profile control
Solution Approach 2:
Instead of using high temperature as the sole control mechanism, the patent introduces organic materials as intermediaries that chemically modify the calcium oxide surface. This intermediary approach achieves hydration control at lower temperatures, making the process easier to manufacture and more commercially viable
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 effectively postpones the hydration initiation of calcium oxide, allowing for controlled and flexible application in cementitious compositions, enabling delayed hydration and reduced exothermic activity.
Implementation Method 1
heating precursor alkaline earth metal oxide particles comprising 40-100% calcium oxide, or a mixture of calcium oxide and magnesium oxide, in the presence of organic material comprising a carbohydrate, amino-carboxylic acid, or mixture thereof
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides compositions and methods relative to controlling hydration onset of an alkaline earth metal oxide such as calcium oxide, comprising heating an inorganic alkaline earth metal oxide to sub-calcination temperatures in the presence of organic material comprising a carbohydrate, an amino-carboxylic acid, a hydroxycarboxylic acid, or a mixture thereof. Preferred treated particles comprise at least 40% and more preferably at least 80% by dry weight calcium oxide which is heated in the presence of ascorbic acid and a starch. Treated particles of the present invention manifest an unexpected, surprising hydration induction postponement behavior as demonstrated through calorimetric testing.