Lithium-Silicate Binder Mixing for Stable Foundry Molds and Cores
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Solution Overview
Problem
Existing inorganic binders in the foundry industry, particularly those containing lithium ions, suffer from instability and poor storage stability, leading to issues such as turbidity and precipitation, which affect processing and handling of molds and cores.
Innovation Solution
A method involving a kit comprising separate components with adjustable lithium ion concentrations, where the molar modulus SiO₂/M₂O in one component is higher than in the final mixture, allowing for flexible adjustment of lithium ion content to enhance storage stability and strength, using a combination of aqueous solutions and dispersions to form a molding material mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic binders containing lithium ions are used to produce molds and cores, then the strength and storage stability are improved, but the solution becomes unstable leading to turbidity and precipitation
Solution Approach 1:
The binder system is segmented into multiple components: water glass solution, lithium-containing solution, and optional additional additives. Each component can be stored separately in stable form and combined before use, preventing the instability and precipitation issues that occur when lithium ions are present in the binder solution during storage.
Solution Approach 2:
The necessary components are prepared in advance in stable forms (water glass solution and lithium-containing solution stored separately). The actual mixing to create the lithium-containing water glass binder occurs only immediately before application, ensuring the binder maintains its stability during storage while providing the desired strength properties when used.
2Reliability
If high concentration of lithium ions is used in the binder, then the storage stability and strength are enhanced, but the processing and handling become difficult due to turbidity and precipitation
Solution Approach 1:
The binder system is divided into stable precursor components that can be stored and handled separately without processing difficulties. The high-concentration lithium-containing solution and water glass solution are kept separate during storage, eliminating turbidity and precipitation issues, and are combined only when needed for mold and core production.
Solution Approach 2:
The system transitions from a static unstable mixture to a dynamic multi-component system where components are combined on-demand. This allows the binder to maintain optimal stability during storage while providing the necessary high lithium ion concentration for strength and storage stability of the final mold or core product.
3Ease of operation
If organic binders are used, then the processing is easy, but harmful emissions such as benzene, toluene, and xylene are generated during decomposition
Solution Approach 1:
The binder chemistry is changed from organic to inorganic composition. The inorganic binder system (water glass with lithium ions) decomposes into harmless inorganic substances rather than generating harmful organic emissions like benzene, toluene, and xylene, while maintaining ease of processing through simple mixing and application procedures.
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 method produces molds and cores with high strength and extended storage stability, preventing deformation or breakage during handling and storage, even under varying environmental conditions, while minimizing material costs and ensuring consistent quality.
Implementation Method 1
a solution or dispersion comprising lithium-containing water glass... comprising a molding base material and a solution or dispersion comprising lithium-containing water glass
Data Source
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Figure 3
AI summary
A description is given of a method for producing a moulding material mixture or for producing a moulding material mixture and a moulded body thereof, preferably casting moulds or cores, for use in the casting industry, wherein the moulding material mixture comprises a moulding base material and a solution or dispersion comprising lithium-containing sodium silicate, comprising the steps of: (1) producing or providing a kit at least comprising as separate components: (K1) an aqueous solution or dispersion comprising sodium silicate and (K2a) a first sodium-silicate-free solution or dispersion comprising lithium ions dissolved in water and preferably (K2b) a second sodium-silicate-free solution or dispersion, preferably comprising lithium ions dissolved in water of a lower concentration than in component (K2a), and then (2) producing a mixture of the moulding base material with a proportion of the component (K1) and with a proportion of the component (K2a) and also optionally with a proportion of the component (K2b). Also described is an aforementioned kit, in particular for use in the method according to the invention. Also specified is an installation for producing an intermediary solution or dispersion, comprising lithium-containing sodium silicate for use in the production of a moulding material mixture or for the production of a moulding material mixture and a moulded body thereof.