High-aluminum refractory mud is prepared from high-alumina bauxite clinker, binders, and admixtures. It is usually delivered dry in bulk and is mixed with water when used. Solemn reminder: Refractory mud is different from refractory cement. Refractory mud is mainly used as joint material or brick joint material for building refractory bricks. The adjusted refractory mud is also called refractory mortar. Refractory cement is used as a binding agent to make refractory castables or refractory plastics. Refractory cement is also called high alumina cement or aluminate cement.
The role of high alumina refractory mud admixtures
Soft clay is added to high-alumina refractory mortar to improve workability, such as spreadability and adhesion. Using fume silica powder instead of soft clay can reduce the sintering temperature. Admixtures mainly include dewatering agents, stabilizers, plasticizers, and anti-shrink agents. The function of a precipitation agent is to reduce the amount of water added. The stabilizer prevents solid-liquid separation of the prepared refractory mud during the standing process. Plasticizers are added to improve the spreadability of the mud and prevent it from flowing. Anti-shrinkage agent is used to prevent cracks or peeling due to volume shrinkage after sintering.
Advantages and characteristics of high alumina refractory mud
- (1) Good plasticity and convenient construction.
- (2) High bonding strength and strong corrosion resistance.
- (3) High refractoriness, up to 1750℃.
- (4) Good resistance to slag invasion.
- (5) Good thermal peelability.
How to use high alumina refractory mud
The refractory slurry used for refractory bricks is made of powdery refractory materials. It should have good masonry performance and high temperature performance, and bond the refractory bricks into a dense overall furnace lining.
The masonry performance of mud refers to the working performance of refractory mud that is beneficial to ensuring the quality of masonry during the masonry process. If it has good fluidity and plasticity. It has certain water retention properties and can maintain a uniform state without segregation and precipitation. It must have appropriate consistency and viscosity during masonry, and must not dry out during brick rolling to achieve the required brick joint thickness, and the mortar inside the brick joints must be full.
The high-temperature performance of mud refers to the performance of ensuring that refractory bricks work at high temperatures. Its main indicators are:
- (1) Sufficient refractoriness.
- (2) Sufficient bonding strength to combine the masonry into a solid whole within the working temperature.
- (3) Small drying shrinkage and high-temperature residual shrinkage values, and strive to prevent brick joints from cracking after high-temperature use.
- (4) The apparent porosity and air permeability are small, and the air tightness is good.
- (5) It can resist the erosion of gas, slag, and molten iron.
- (6) The thermal expansion coefficient is consistent with that of refractory bricks. Since the working temperatures and operating conditions of various parts of the blast furnace and its ancillary equipment are different, different types and compositions of mud should be selected for different masonry structures.
When choosing refractory clay, you should consider that it has a chemical composition similar to that of refractory bricks. Make the thermal expansion of the mud consistent with the thermal expansion of the bonded refractory bricks to ensure that the masonry can be reliably bonded.
Uses of high alumina refractory mud
High alumina refractory mud is correctly configured according to the material of refractory bricks. Usually, high alumina bricks and corundum bricks are mainly used.
Unshaped Refractory Materials 