Fused ceramic sand and sintered ceramic sand are two primary product types, each with distinct benefits and applications. Below is a comparison of their main differences and advantages:
Fused Ceramic Sand:
Raw Materials: Calcined bauxite with an aluminum content of 70-80%.
Production Process:
The raw material is first crushed using a jaw crusher.
The crushed bauxite is then fed into an electric arc furnace, where it is melted into a liquid using the high temperatures generated by arc discharge (around 2000°C).
The liquid is subjected to an air pressure of 70-85 m/s (3.0-8.0 kg/m²), causing it to break into spherical or near-spherical particles through rapid cooling.
Characteristics: Rapid cooling results in a more uniform shape, with particles being spherical or nearly spherical.
Sintered Ceramic Sand:
Raw Materials: Calcined bauxite with an aluminum content of 45-75%, mixed with other auxiliary materials.
Production Process:
The bauxite is crushed through a two-stage system consisting of a jaw crusher and a hammer crusher.
The crushed bauxite is mixed with auxiliary materials according to the formula and ground in a ball mill, then classified to obtain the required mixture.
In the granulation pot, a "starter" is added. Under atomized water spraying, material is continuously fed into the pot, where it undergoes rolling, friction, and extrusion due to the clockwise rotation of the pot, ultimately forming spherical particles.
The spherical particles are calcined in a rotary kiln at a temperature of 1200-1400°C to produce high-strength ceramic sand.
1. Manufacturing Process
Fused Ceramic Sand: Made by melting alumina-silica-based minerals and then rapidly cooling them. This process removes impurities, enhancing heat resistance and chemical stability.
Sintered Ceramic Sand: Produced through a powder metallurgy process, in which raw particles are sintered at high temperatures without melting. This method can be more cost-effective.
2. Physical Properties
High-Temperature Resistance: Fused ceramic sand typically has a higher refractory temperature, making it suitable for casting operations that require extreme heat tolerance.
Sphericity: Fused ceramic sand grains are generally more spherical, offering better flowability, which improves casting density and reduces porosity.
Hardness and Compressive Strength: Fused ceramic sand has higher hardness and can retain its shape under high-pressure casting, minimizing sand degradation and sand loss.
Sintered ceramic sand has lower bulk density. Reducing Mold Weight: Sand materials with lower bulk density are overall lighter, which can significantly reduce the total weight of the mold, making it easier to handle and transport while reducing the demand on equipment and labor.
Saving Material Usage: With lower bulk density, the sand covers a larger volume for the same weight, meaning less material is required to fill the mold, which helps reduce material costs.
3. Chemical Stability
Chemical Resistance: Fused ceramic sand has superior chemical stability, particularly beneficial for casting iron and acid- or alkali-resistant metals. It is less likely to react with metals at high temperatures, reducing casting defects.
4. Service Life and Cost Efficiency
Reusability: Fused ceramic sand has a low breakage rate and high recyclability, which can significantly reduce casting costs over time.
Initial Cost: Sintered ceramic sand is more economical to produce, making it suitable for budget-conscious users, although fused ceramic sand can offer better overall cost-effectiveness for high-end casting needs.
5. Application Areas
Fused Ceramic Sand: Commonly used in precision casting, especially for steel and stainless steel parts that demand high surface quality and accuracy.
Sintered Ceramic Sand: Generally used in standard casting, such as for cast iron parts or non-metal castings where precision requirements are lower.