Low-Density Ceramic Composition via Carbonate Decomposition
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Solution Overview
Problem
Existing methods for producing low-density ceramic tiles often result in the 'Black heart' defect due to excess organic material and oxygen deficiency during firing, leading to deformities and surface flaws, and struggle with maintaining low apparent densities when using high internal porosity materials like volcanic minerals or ceramic foams, which limit shaping and decoration processes.
Innovation Solution
A ceramic composition comprising high percentages of +2 valency group carbonates (calcium, strontium, and magnesium) combined with +1 valency group oxides, along with natural and synthetic binders, allowing for shaping by pressing and decoration using current manufacturing systems, while maintaining low apparent density and dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If organic material is added to produce low-density ceramic, then low apparent density is obtained, but 'Black heart' defect occurs due to excess organic material and oxygen deficiency during firing
Solution Approach 1:
The patent changes the chemical composition parameters by using +2 valency group carbonates (CaCO3, MgCO3, SrCO3) instead of organic materials. These carbonates decompose during firing to produce CO2 gas that creates porosity without causing black heart defects, as the decomposition occurs with sufficient oxygen availability unlike organic material combustion
Solution Approach 2:
The patent uses carbonates that temporarily exist during processing and decompose during firing to create the desired porosity. The carbonates serve their purpose of creating gas bubbles for porosity formation and then are consumed/decomposed, leaving no harmful residues that would cause defects
2Weight of stationary object
If high internal porosity materials like volcanic minerals or ceramic foams are used, then low apparent density is obtained, but shaping by pressing becomes difficult due to porosity occlusion
Solution Approach 1:
The patent uses carbonate particles with specific size distribution (0.63-2.0 mm rejection ≤5%, 0.063-0.63 mm rejection ≤10%) and controlled morphology that maintain porosity during pressing. The porosity is created by gas evolution during firing rather than pre-existing physical porosity, resolving the contradiction between low density and pressability
Solution Approach 2:
The carbonate decomposition and porosity creation happens as a preliminary action during the firing process itself, rather than relying on pre-formed porous structures. This allows the green body to be densely packed during pressing, then porosity is generated in situ during firing through carbonate decomposition
3Weight of stationary object
If +2 valency group carbonates are used to reduce density, then low apparent density is obtained, but liquid phase formation increases density during firing
Solution Approach 1:
The patent carefully controls the ratio of +2 valency group carbonates (40-70%) to +1 valency group oxides (10-60%) to manage liquid phase formation. By adjusting these compositional parameters, the patent suppresses excessive liquid phase that would increase density, while maintaining enough liquid phase to bind the structure and prevent collapse of the porous framework
Solution Approach 2:
The patent creates localized porosity through carbonate decomposition at specific sites throughout the ceramic matrix. The +1 valency group oxides (alkali feldspars) are distributed to provide localized liquid phase only where needed to bind particles, rather than forming a continuous dense liquid phase throughout the entire structure
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 composition enables the production of low-density ceramic parts with improved mechanical strength and versatility in shaping and decoration, avoiding the 'Black heart' defect and maintaining low density through calcination-induced porosity reduction, suitable for use in construction and composite materials.
Implementation Method 1
raw materials are added with high loss by calcination comprised of carbonates that are elements of the +2 valency group
Implementation Method 2
the sintered composition is comprised of elements of the +2-valency group and silicon-aluminates that contain +1 valency group oxides in the appropriate proportions to prevent an increase in the apparent density of the finished part
Data Source
AI summary
The invention relates to a ceramic composition which allows the production of ceramic parts with a low fired density. The sintered composition of the present invention contains percentages higher than 40 and lower than 70, in dry weight, of the sum of carbonates of elements of the group of a valency of +2, and also includes a percentage of between 10 and 60, in dry weight, of the sum of silico-aluminates which provide oxides of elements that have a valency of +1 (Na2O, K2O and Li2O). It optionally includes up to 50%, in dry weight, of degreasing or plastic materials. In this way, said composition is used to produce low-density ceramic parts which are suitable for placing on the ground, on walls and on roofs and which can also act as structural elements for producing ceramic-polymer or ceramic-metal composites.