Continuous Sol-Gel Process for Quartz Glass Production
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Solution Overview
Problem
Discontinuous processes for quartz glass production lead to quality inconsistencies, air bubble inclusion, and extensive cleaning requirements, limiting scalability and efficiency.
Innovation Solution
A continuous sol-gel process involving continuous metering and degassing of silicon alkoxide and silica dispersion, followed by pH adjustment and degassing of the presol, to produce high-quality quartz glass with consistent quality and reduced cleaning needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discontinuous processes are used for quartz glass production, then flexibility in production quantity is maintained, but quality inconsistencies and air bubble inclusion occur
Solution Approach 1:
The patent implements a continuous sol-gel process where silicon alkoxide, water, and acid catalyst are continuously fed into a reaction vessel, maintaining continuous hydrolysis and condensation reactions. This eliminates the start-stop nature of batch processes, ensuring consistent quality while improving production efficiency through uninterrupted operation
2Ease of manufacture
If discontinuous processes are used for quartz glass production, then equipment simplicity is maintained, but extensive cleaning requirements arise
Solution Approach 1:
The continuous process operates without interruption, with reactants continuously flowing through the system. This eliminates the repeated cleaning cycles required between batch operations, significantly reducing time loss while maintaining equipment simplicity through a straightforward continuous flow design
3Productivity
If continuous process is implemented, then productivity and quality consistency are improved, but process complexity increases
Solution Approach 1:
The continuous process is divided into distinct functional segments: a reaction vessel for hydrolysis and condensation, a degassing system for bubble removal, and a drying system for solvent evaporation. This segmentation allows each component to be relatively simple while achieving high productivity and quality consistency through their coordinated continuous operation
4Reliability
If continuous process is implemented, then air bubble inclusion is reduced, but additional degassing equipment is required
Solution Approach 1:
The degassing system is integrated into the continuous process flow, removing air bubbles from the sol before it enters the drying and forming stages. This preliminary removal action prevents bubble inclusion in the final product while using equipment that does not significantly increase overall process complexity
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 production of any desired quantity of high-quality quartz glass with reduced air bubbles and simplified cleaning, enhancing scalability and profitability.
Implementation Method 1
continuous metering of a silicon alkoxide into a first reactor (R1) and at least partial hydrolysis by adding an aqueous mineral acid
Implementation Method 2
the sol-gel process is based on an acid or base catalyzed hydrolysis and the subsequent gelling of silanes, siloxanes and organosilanes by condensation reactions
Implementation Method 3
Both feedstocks had previously been degassed using ultrasound
Implementation Method 4
drying the aquagels to obtain xerogels
Implementation Method 5
sintering the xerogels to obtain quartz glass
Data Source
AI summary
The invention relates to a continuous sol-gel method for producing quartz glass, comprising the following steps: (a) continuously metering a silicon alkoxide into a first reactor (R1) and carrying out an at least proportional hydrolysis process by adding an aqueous mineral acid, thereby obtaining a first product flow (A); (b) continuously producing an aqueous silicic acid dispersion by continuously mixing water and silicic acid in a second reactor, thereby obtaining a second product flow (B); (c) continuously mixing the product flows (A) and (B) in a third reactor (R3) in order to produce a pre-sol, thereby obtaining a third product flow (C); (d) continuously adding an aqueous base to the product flow (C), thereby obtaining a sol; (e) continuously filling the exiting sol into molds, thereby obtaining an aquagel; (f) drying the aquagel, thereby obtaining xerogels; and (g) sintering the xerogels, thereby obtaining quartz glass, with the proviso that at least one of the steps (a) to (e) additionally includes a degassing process of at least one feed material used in the step.