What chemical can be used to remove dried alumina powder from stainless steel? R.N.
Your cleaning challenge is not so much a chemical issue as it is a mechanical issue. Alumina will not dissolve in any conventional cleaner. I assume this is residue left over from mechanical blasting of a surface. Hopefully the surface was clean (grease and oil free) prior to the blasting. If not, I would recommend a standard aqueous or solvent cleaning process to remove residual process oils from your part prior to blasting.
After blasting, there will be residual abrasive that will stick to the surface. Something as simple as a pressure washer may suffice to remove this. If there is other residue (oil with the alumina), then a detergent solution with some sort of mechanical force behind it will be necessary in order to get the parts clean and free of alumina. A spray washer or agitated immersion tank (with filtration) would work well for this application. Again, I would suggest removal of the oil before blasting, though, since the blasting may “embed” contaminants into the surface and make them significantly more difficult to remove later.