Abstract: The effects of carrier roasting furnace type, mesh belt running frequency, carrier bed thickness, roasting temperature, modified gas flow rate and converter pre-roasting temperature on the pore properties of alumina carrier were investigated. The results showed that the specific surface area of alumina carrier calcined by converter was smaller, the volume distribution ratio of the pore diameter of 2-6 nm was low, while the volume distribution ratio of the pore diameter of 6-20 nm was high. Without gas modification, the carrier calcined in mesh belt kiln had a larger specific surface area, but the volume distribution ratio of the pore diameter of 2-6 nm was relatively high and the volume distribution ratio of the pore diameter of 6-20 nm was relatively low. With proper gas modification and other process condition optimization, the volume distribution ratio of the pore diameter of 2-6 nm could be reduced and the volume distribution ratio of the pore diameter of 6-20 nm increased. The optimized process conditions of mesh belt kiln were as follows: roasting temperature (benchmark +15)℃, electricity frequency (benchmark +2)Hz, material layer thickness (benchmark +8)cm, modified gas amount (benchmark+20)m³/h. When the carrier was roasted in converter, it could be optimized by adjusting the pre-roasting temperature. When the pre-roasting temperature was (benchmark +140)℃, the volume distribution ratio of the pore diameter of 6-20 nm could reach 91.22%.

Key words: pore distribution, carrier, mesh belt roaster, rotary roaster, modified gas