Grinding sound while wheels are turning after braking not ice or stones

Hi

this is very common espcially on older cars, there shold be a dust sheild on the back of the front brake discs, they often rot and start to bend in wards touching the brake disc while turning, you can bend them back out but on the most part when they are this bad they just fall off in your hand, it is only thin metal, may be tricking to see you will have to stick your head under the front wheel to have a look or may need a ramp if the car is low.

Hope this helps
Regards

Dan