I. Raw Materials and Additives for Sanitary Ceramic Slurry
Sanitary ceramic slurry is usually produced by slip casting, which requires high fluidity, stability, and green strength.
Main Raw Materials:
Kaolin: Provides high whiteness, good firing properties, and low shrinkage; serves as the skeletal material.
Ball Clay: Increases plasticity and drying strength, compensates for the insufficient plasticity of kaolin, and improves slurry suspension and molding properties.
Feldspar: The main flux, lowers firing temperature, promotes densification, reduces water absorption, and increases strength.
Quartz: A lean material, reduces drying and firing shrinkage, prevents cracking and deformation; increases mechanical strength.
Common Additives:
Deflocculants: Reduce slurry viscosity, improve fluidity, facilitate casting, and increase efficiency. Common examples include: sodium silicate, sodium metaphosphate (sodium hexametaphosphate), sodium humate, and sodium polyacrylate.
Binders: Improve the mechanical strength of green bodies and reduce breakage rates during demolding, trimming, and drying. Common examples include: carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and starch.
Defoamers: Inhibit the generation of air bubbles during slurry mixing and casting, preventing porosity in the product.
Stabilizers: Improve slurry suspension stability and prevent particle sedimentation. Common examples include: bentonite (in small amounts) and CMC.
Flocculants: (In specific cases) Improve slurry thixotropy or aid particle settling.
II. Raw Materials and Additives for Sanitary Ceramics Glaze
The glaze surface of sanitary ceramics is required to be smooth, glossy, wear-resistant, stain-resistant, free of pinholes and cracks.
Main Raw Materials:
Fused Clinker: The core of the glaze, providing a uniform and stable chemical composition, lowering the glaze's melting point and firing temperature, and reducing defects.
Feldspar: A flux, working with the fused clinker to adjust melting characteristics and provide a glassy phase.
Quartz: Provides silica, increasing the glaze's hardness, stability, and abrasion resistance.
Clay: Provides suspension and green strength, prevents glaze slurry sedimentation, provides alumina, and improves glaze strength and chemical resistance.
Talc: A flux, improving glaze gloss and reducing the coefficient of thermal expansion.
Zinc Oxide: A flux, reducing glaze viscosity, improving glaze gloss, and contributing to an opaque effect.
Common Additives:
Suspension Agents: Prevent glaze particles from settling, maintain uniformity, and improve rheological properties and adhesion. Common examples include: CMC, bentonite, and veegum (magnesium aluminum silicate).
Deflocculants/Dispersants: Reduce glaze viscosity, improve flowability, and prevent streaks or unevenness during spraying. Common examples include: sodium tripolyphosphate and sodium metaphosphate.
Defoamers: Prevent air bubbles from forming during glaze stirring or spraying, avoiding pinholes on the glaze surface.
Wetting Agents/Wetting Agents: Reduce the surface tension of the glaze, allowing it to better wet the body and reduce defects such as glaze shrinkage and flow.
Binders: Improve the adhesion and strength of the glaze layer on the body, preventing powdering. Common examples include: CMC and PVA.
Colorants: (Specially designed) Adjust the glaze tone.
Opacifiers: Make the glaze opaque, giving it a milky luster and increasing whiteness. Common examples include: zirconium dioxide, tin oxide, and titanium dioxide.