Corundum quality refractory castables are made from corundum to the new jade refractory insulation material containing al2o3 90% refractory insulation material products, and the main crystalline phase is alpha iron oxide (corundum). alpha is 1 crystallization, which is 1 true relative density 3.85 short column.
Strength 9, melting point 2050, melting point 4.01. corundum has the characteristics of heat resistance, high toughness, high-temperature compressive strength, good abrasion resistance, strong resistance to solvent corrosion, and good sealing properties.
However, the thermal deformation rate is high and the heat transfer coefficient is high. Thus, corundum can be used as a raw material for refractory insulation materials, and are key synthetic wear-resistant materials.
Composition of Corundum Refractory Castables
The key ingredients of corundum wear-resistant refractory castables should be high alumina stone, corundum, alpha alumina micro-powder, appropriate explosion-proof chemical fibers, etc. According to the effective mechanism of pure calcium aluminate cement fusion wear-resistant refractory castables.
Corundum wear-resistant fireproof castable has high compressive strength, good abrasion resistance, heat shock resistance, and good corrosion resistance.
Corundum wear-resistant refractory castables are generally applicable to boilers, gasification furnaces, circulating system fluidized bed boiler lining and chemical plants, kiln mouth, kiln hood, grate cooler wear-resistant pier ideal selection.
Corundum is generally made from industrially produced iron oxide or bauxite after calcination or electrofusion fittings. When iron oxide is melted with industrially produced iron oxide, white corundum is obtained with a water content of iron oxide exceeding 98.5%.
When high alumina bauxite as raw material, general brown corundum or iron oxide corundum (also known as sub-white corundum or gray-brown corundum) is obtained. Its Al2O3 content of 91%.98.5%, plate corundum melting method and forging method, the temperature reaches about 1950 degrees, iron oxide particulate matter over work-hardening α-Al2O3, in the optical microscope produces a crystalline plate, a short columnar structure. Comparison with electrofusion fittings white corundum, with the heat shedding and granular compressive strength.
Concrete industrial kilns are commonly used as fireproof stone, used for high temperature, wear resistance, corrosion resistance, kiln nozzle, and coal injection pipe temperature shift often.
The Raw Material Composition Of Corundum Refractory Castables Has Various Forms, Such As.
1. white corundum is used as stone and granular material.
2. Slave iron oxide and high-density (calcined) iron oxide for stone and high-density (calcined) iron oxide for granules.
3. Use white/brown corundum as stone and high-density (calcined) iron oxide as granule.
4. using white corundum and special grade alumina cement clinker as stone, using white corundum as a granular material, etc.
To improve the cultivation matrix characteristics of corundum refractory castables, white corundum powder or plate alumina powder is generally used as its granular material composition. According to the provisions of corundum refractory castable material overall target characteristics, effective selection of particulate matter throughout the index as a recipe for fitting particulate matter preparation. The specific filler in the fusion system software, widely used SiO2 powder (often called silica fume) or specific a-Al2 powder (alumina powder), and so on.
Depending on the application, corundum refractory castables are usually configured with or without concrete. In the first case, concrete or concrete and specific micro-powder is used as the fusion agent, while in the second case, specific micro-powder is used as the fusion agent. In addition, high-efficiency surface activators (high-efficiency thickeners and admixtures) are added to disperse the fusing agent and the special filler and to reduce the water requirement.
Generally speaking, corundum refractory castables in the granular material + specific filler (micro-powder) combined amount (molar mass) of % ~ 34% of the raw material type is not the other. The amount of specificity filler will not be the same, but the better specificity filler quantity in the middle of 4%~%.
In addition, corundum refractory castables must be added to the high-efficiency surface layer activator (high-efficiency thickener and additives) to disperse the fusion agent and specific filler. To facilitate the corundum refractory castable slurry to get good circulation and better engineering construction characteristics.
In corundum refractory castables, fusion agents, specificity filler, and anticorrosive agents are used in very small quantities, but all of them are very crucial and closely related to the three small components, which are indispensable.
The selection of each component becomes the key condition to manipulate the thixotropic properties of corundum refractory castables. The specification of the selection is to ensure that the relative corundum refractory castables over the engineering construction characteristics of the provisions.
This can be maintained using elevated preservatives (efficient thickeners and admixtures). For example, it is possible to add a variety of preservatives (additive packages), each of which has a different effect, to modify the thixotropic properties of corundum refractory castables.
Efficacy Of Specific Filler In Corundum Refractory Castables
The effect principle of specificity filler is very complicated, but its essential effect principle is to play the effect of filling. Because of the refractory castable ratio, the apparent density is very large, and high density, but there is still a lot of porosity.
If you use a specific filler (powder) to add this porosity, you can reduce the porosity greatly reduced, and then significantly reduce the amount of water required for refractory castables, so that the pouring of prefabricated components or fireproofing lining body dry (baking) after the air left after the great reduction in the pore.
In other words, by incorporating specific fillers into the refractory castables, the amount of water required can be reduced. In addition, to enhance its relative density, reduce porosity, specific filler water content of less than 5%, stone a grain of material between the empty yard is not full.
Therefore shall be higher water demand, high porosity, relative density, and specificity filler water content over 7%, with specificity filler added out of the air holes.
The rest of the specificity of the filler must also be water, the same will also cause the raw material porosity to increase, and relative density to decrease, but the apparent porosity will not easily have a significant shift.
The actual use of the casting material effect shows that the actual effect of silica micro powder filling than alumina powder is good to use. Its water requirement is less due to the use of silica micropowder-specific filler to add the actual effect of not only suffering from the hazards of particle specifications.
And also suffer from its object appearance and specificity of the harm. Silica micro powder is spherical, and specificity, its filling, and actual effect are neighboring than granular non-specific air oxidation powder.
