[FrankJ]

You have a few choices grinding Aluminum. We use a bench sander & sanding disks on our angle grinder rather than grinding. Flapper wheels work also.

1(Probably best ) use wheels rated for Aluminum.
2 Use lots of lubricant like WD-40. Never done this. I am told that it is messy.
3 Don't let the wheel load up. Which will require frequent redressing. Not the best of ideas.