Silicate-Coated Set Accelerators for Refractory Aging
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Solution Overview
Problem
Monolithic refractory compositions experience unpredictable and prolonged set times due to aging, making it difficult to achieve consistent hardening, even with the addition of set accelerators, which can result in either delayed or too rapid setting.
Innovation Solution
Incorporating silicate-coated set accelerator particles, such as silicate-coated calcium hydroxide, into the refractory compositions to reduce initial set times and stabilize the hardening process, allowing for consistent set times even after prolonged storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional set accelerators are added to aged refractory compositions, then initial set times are reduced, but the composition may set too quickly resulting in unacceptably short working times
Solution Approach 1:
A silicate coating is applied to the set accelerator particles (such as calcium hydroxide), creating an intermediary layer that controls the release rate of the active ingredient. This coating acts as a mediator between the set accelerator and the refractory composition, enabling gradual activation and preventing sudden rapid setting that would shorten working time.
Solution Approach 2:
The invention changes the physical-chemical parameters of the set accelerator by coating it with silicate, which modifies its reactivity and dissolution rate. This parameter change allows the set accelerator to function more predictably in aged compositions, reducing initial set time without causing excessively rapid setting that would compromise working time.
2Duration of action of stationary object
If refractory compositions are stored for extended periods, then availability is improved, but reactivity decreases causing prolonged and unpredictable set times
Solution Approach 1:
The silicate coating is applied to the set accelerator particles in advance during manufacturing, creating a pre-conditioned material that maintains stable properties during storage. This preliminary action protects the set accelerator from premature reaction with moisture during storage, ensuring consistent performance when the composition is eventually used.
Solution Approach 2:
The silicate coating serves as a sacrificial, consumable layer that gradually dissolves or reacts during the setting process, releasing the set accelerator in a controlled manner. This disposable protective layer enables the set accelerator to remain stable during storage but become progressively active during use, regardless of how long the composition has been stored.
3Ease of operation
If moisture is present during storage, then compositions remain workable, but fine components react with moisture causing delayed hardening
Solution Approach 1:
The active set accelerator is extracted from its reactive state during storage by enclosing it within a silicate coating. This separation prevents premature interaction between the set accelerator and moisture in the environment, while still allowing the composition to remain workable. During setting, the coating gradually breaks down and releases the set accelerator to initiate hardening.
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 use of silicate-coated set accelerator particles decreases initial set times and reduces the impact of aging on set times, providing more predictable and stable hardening across both fresh and aged compositions, enabling effective recovery of aged compositions that would otherwise not set within acceptable times.
Implementation Method 1
the use of a silicate-coated set accelerator, such as silicate-coated calcium hydroxide, in the refractory composition decreases the initial set time and reduces the effect of aging on the set time
Data Source
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AI summary
A refractory composition including refractory aggregate, one or more matrix components, and silicate-coated set accelerator particles. The silicate-coated set accelerator particles can include one more of silicate-coated calcium hydroxide, magnesium hydroxide, calcium chloride, calcium carbonate, magnesium carbonate and calcium sulfate. Suitable silicate coatings include sodium silicate, potassium silicate, lithium silicate and mixtures thereof. A method of recovering an aged refractory composition, a settable composition and a method of manufacturing silicate-coated calcium hydroxide particles are also provided.