Vacuum Calcining of Gypsum for Low-Energy Hemihydrate Production
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Solution Overview
Problem
Existing gypsum hemihydrate production processes require high temperatures and pressures, leading to increased energy costs, reduced product strength, and extended manufacturing times.
Innovation Solution
Calcining gypsum dihydrate under vacuum at relatively low temperatures (60° C. to 125° C.) and controlled vacuum pressures (25 mbar to 50 mbar) for a predetermined time (3 to 10 hours) to remove water of crystallization, forming gypsum hemihydrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high temperature calcining is used to produce gypsum hemihydrate, then the water of crystallization is effectively removed, but energy consumption increases and product strength decreases
Solution Approach 1:
The patent changes the physical parameters of the calcining process by applying vacuum conditions (reducing pressure) to enable water removal at lower temperatures (60-125°C compared to conventional high temperatures), thereby reducing energy consumption while maintaining effective dehydration
Solution Approach 2:
The patent uses vacuum conditions to create an inert environment that facilitates water removal from gypsum dihydrate without requiring high temperatures, effectively replacing the need for thermal energy with pressure differential-driven dehydration
2Strength
If high temperature calcining is used to remove water of crystallization, then dehydration is achieved, but product compressive strength is reduced
Solution Approach 1:
The patent changes the calcining parameters from high temperature to low temperature operation under vacuum conditions, producing gypsum hemihydrate with enhanced compressive strength by avoiding thermal degradation that occurs at conventional high calcining temperatures
3Productivity
If conventional high temperature processing is used, then water removal is efficient, but manufacturing time is extended
Solution Approach 1:
The patent changes the processing parameters by using vacuum-assisted low temperature calcining, which achieves effective water removal in a controlled time frame (3-10 hours) while consuming less energy than conventional high temperature prolonged heating processes
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 method produces gypsum hemihydrate with enhanced compressive strength and reduced energy consumption, while minimizing thermal damage and processing time.
Implementation Method 1
subjecting a composition including gypsum dihydrate to a vacuum of from 25 mbar to 50 mbar
Implementation Method 2
maintaining the composition under the at least partial vacuum at a calcining temperature of from 65° to 85° C. for a predetermined calcining time
Data Source
AI summary
A method for calcining gypsum includes subjecting a composition including gypsum dihydrate to a predetermined vacuum. The method further includes maintaining the composition under the at least partial vacuum at a calcining temperature for a predetermined calcining time. The calcining temperature may be in a range from 60° C. to 125° C., or in a range from 65° C. to 85° C. The vacuum may be in a range from 25 mbar to 50 mbar. The predetermined calcining time may be in a range from 3 hours to 10 hours. The maintaining is effective to at least partially remove water of crystallization from the gypsum dihydrate to convert the composition to a product including gypsum hemihydrate.