ALTRON from Blasch, 75% silicon carbide in an alumina bond, for air grid nozzles, cyclone liners, lined pipe and dust collectors.
Dense advanced ceramics resist erosion, until heat or a hard landing cracks them.
ALTRON sits in between, by design.
Alumina bonded silicon carbide is used for erosion because its abrasion resistance approaches that of much more expensive, fully dense advanced ceramics, while it keeps the thermal shock tolerance of a less dense refractory grade. That makes it the choice where particles wear through steel and a dense ceramic would crack from thermal or mechanical stress, or would simply cost too much. Blasch ALTRON loses 1.5 cc in the ASTM C704 abrasion test and is used for FCC air grid nozzles, cyclone liners and lined pipe.
Alumina bonded silicon carbide is silicon carbide whose grains are held together by an alumina phase. Blasch ALTRON contains 75% SiC, 24% alumina and 0.9% silica, with an apparent porosity of 5 to 10%.
That porosity is low enough for strong abrasion resistance and high enough to let the structure absorb thermal stress. ALTRON also resists oxidation at elevated temperature, which matters in hot flue gas and catalyst service.
ALTRON can be cast into relatively complex shapes with good tolerance control, without the hard tooling setup charges of pressed ceramics. How the Blasch process works
Values from the Blasch ALTRON product information sheet.
| Property | ALTRON |
|---|---|
| Composition | 75% SiC, 24% Al2O3, 0.9% SiO2 |
| Apparent porosity | 5 to 10% |
| Modulus of rupture, room temperature | 5,600 psi (38 MPa) |
| Erosion, ASTM C704 | 1.5 cc loss |
| Bulk density | 170 to 180 lb/ft³ |
| Thermal conductivity | 166 BTU·in/hr·ft²·°F |
Erosion parts rarely fail because the material is too soft; they fail because it cracks, and ALTRON is designed to be hard enough without being fragile.
Abrasion close to dense ceramics: with 1.5 cc loss in the ASTM C704 test, ALTRON comes close to the dense grades in erosion, at a lower price.
No cracking from thermal stress: where a dense advanced ceramic cracks from thermally induced or other mechanical stress, ALTRON keeps the thermal shock tolerance of a refractory grade.
Weldable assemblies: ALTRON FCC air distributor nozzles are ceramic metal assemblies that are welded into the grid in place of the steel nozzle, so the grid itself does not change.
FCC regenerators: air grid nozzles in the regenerator see catalyst at high velocity and temperature. The material choice for these nozzles is the subject of Hard Choices, Hydrocarbon Engineering, 2014, and of Abrasion Resistant Alumina Bonded Silicon Carbide Air Grid Nozzles.
Coal fired power plants: material selection against erosion in coal and ash handling is covered in Ceramics Win the War on Erosion. In SiClone multicyclone dust collectors, ALTRON and OXYTRON replace cast iron.
Where the particles are coarse and impact is heavy, the denser reaction bonded silicon carbide is the next step. For molten aluminum, use the non wetting OXYTRON 015XDII.
Parts for erosive flow in refining, power and mining.
Ceramic metal nozzles welded into FCC air grids instead of steel nozzles.
One piece cones, apexes and scrolls for slurry and dust.
Cast liners in steel housings for pneumatic conveying and slurry.
Multicyclone outlets, inlets and spin vanes that outlast cast iron.
ALTRON is also used for vortex finders and dip tubes, ceramic pump components, in line chokes and reducers and fluidized bed nozzles. Its main users are in refining and chemical processing, mining and power generation.
ALTRON values and uses: Blasch ALTRON product information sheet and material page; Blasch FCCU wear presentation; Blasch power generation presentation; T. Connors, T. Collins, J. Bolebruch, Hard Choices, Hydrocarbon Engineering, December 2014. Test method: ASTM C704, Standard Test Method for Abrasion Resistance of Refractory Materials at Room Temperature.
No. Abrasive grain is loose silicon carbide or alumina for grinding. ALTRON is a solid cast part made from silicon carbide bonded with alumina.
ALTRON where thermal stress and cost matter and erosion is moderate to severe; reaction bonded where coarse particles and impact dominate at moderate temperature.
Yes. ALTRON air grid nozzles are welded in place of steel nozzles as ceramic metal assemblies, without changing the grid.
Send the part, the medium and the temperature. A Blasch engineer checks whether ALTRON or a denser grade fits your wear.
