the classification of micro silica
1.According to the SiO2 content
◆SiO2≥85%, typical values 88% above, the main control ignition loss (6%), it is used in concrete and low-grade refractory material.
◆SiO2≥90%, typical values about 92%, according to customer require control related impurities, it is used in general refractory material and concrete.
◆SiO2≥92%, typical values about 94%, there are specific requirements, the liquidity requirements for high-grade refractory material.
◆SiO2≥97%, typical values 96% above, there will be strict impurity and PH requirements, but different customers have different focus, it is used in high-grade refractory materials.
2.According to the density
★Original state, 100-170kg/m3, it is easy to bond and poor delivery.
★Mild encryption, 250-400kg/m3, few particles, delivery is improved significantly. But it is instability by the temperature affected.
★Half the encryption, 400-500kg/m3, begin to appear a large number of granular, it is not easy to bond as well as good delivery.
★High density 500-700kg/m3, it is based on the hard particles (different product particle size and tightness). Delivery is excellent.
3.According to particle size or specific surface area
►The median diameter at about 0.3 um, surface area values in 15-25m2/g, all of the particle size≤1um, the majority of micro silica powder is like this in the world.
►The median diameter at about 0.1 or below, surface area values in more than 30m2/g, it generally appears in high purity micro silica powder.
►The median diameter at about 0.5-2.0um, surface area values in 5-15m2/g; rare.
►The median diameter more than 2.0um, very rare, poor using performance.