The differences between high alumina composite bricks and phosphate composite bricks
Both high alumina composite bricks and phosphate composite bricks belong to composite bricks, and the lightweight parts of the composite are both designed to protect the kiln skin. However, there are differences in service temperature and wear resistance between these two types of bricks.
- 1. Raw Materials and Production Processes
High alumina composite and phosphate composite are both formed by dividing the material zone and then high-pressure molding, but their sintering methods are different. High alumina composite bricks are sintered at high temperatures, while phosphate bricks are sintered at low temperatures.
The raw materials for compounding are different: high-alumina compounding is a combination of bauxite and lightweight materials, while phosphate compounding is produced after black material and phosphoric acid solution are used as binders. Only light components are added at intervals during the molding process to optimize the compounding.
- 2. Performance Characteristics
High alumina composites feature high-temperature resistance, high mechanical strength, and a relatively high load-softening temperature. Especially for the super-grade high alumina bricks with an aluminum content of over 80%, the load-softening temperature is even higher, and their service life is longer.
Phosphate composite materials have particularly excellent wear resistance, can withstand sudden temperature changes, and have good resistance to chemical erosion. However, its load-softening temperature is relatively low and its wear resistance coefficient is relatively high. Phosphate composite bricks have a relatively high bulk density and a low porosity, thus they have a higher strength.
- 3. Application Scope
High alumina composite bricks are mostly used in the transition zones of zinc smelting kilns, lime rotary kilns, and spodumene rotary kiln linings, while phosphate composite bricks are used in the transition zones, cooling zones, cooler machines, and kiln head covers of cement rotary kilns. Due to its excellent wear resistance, it is used at the end of the cooling zone, exothermic reaction zone and decomposition zone of rotary kilns. Phosphate composite bricks with light components added can lower the temperature of the kiln skin in rotary kilns and are used in the high-temperature zones of rotary kilns for burning lime, zinc smelting and spodumene smelting, and the application effect is particularly good.
In conclusion, there are significant differences between high alumina composite bricks and phosphate composite bricks in terms of raw materials and production processes, performance characteristics, and application scopes. When making a selection, the choice should be made based on the operating temperature, wear resistance and degree of erosion of the kiln lining.