What are those round metal objects that Jack Torrance is throwing to the floor in this scene in The Shining?
Aluminium plate rings, used for separating dinner plates between plating up & serving; keeps the food warmer for longer.
Plate rings have a characteristic bottom lip which will 'hook' over the plate beneath, & sloped or slightly curving sides, to meet the moulded ring on the underside of the plate stacked above, preventing slippage.
They may have lids, though more usually another empty plate would be placed on top.
For serving - room service etc - a version with an integral lid would be used instead.
Here's a blow-up of the best frame I can find showing 2 of the rings - sloping sides, curved top, external bottom lip; precludes the possibility of cooking ring, baking tin or pie-dish upside down.
For comparison to the most likely alternatives…
Baking tins or pie dishes would have a flat lip on the inside, to provide stability for the flat base insert. A cooking or mousse ring would have no lip at all & also have parallel sides to enable the food to slip out more easily.
Sandwich [cake] tin - flat lip to keep the insert stable
cooking or mousse ring - parallel sides, no lip, edges bent & formed to the outside to keep the inner face as clean as possible.
The script refers to them as "rings"
INT. HOTEL - KITCHEN - M.L.S.
JACK moves forward in kitchen. He sweeps coffee pot off table onto floor. CAMERA TRACKS BACK before him. He kicks coffee pots on floor, then sweeps rings off stove onto floor. He kicks rings as he leaves kitchen, moving into corridor. CAMERA TRACKS BACK before him. He stops and looks ahead.
Cooking Rings are used for a variety of tasks, in this instance (e.g. within a large hotel environment) presumably to assist with plating-up. They may also be used for cooking cakes, pies, omelettes or muffins
Since it's in the kitchen/pantry area, it's likely the ring section of drop bottom pie/cake tins/pans:
Or oddly large muffin or omelet rings. Typical cooking/baking supplies.
The Overlook Hotel is a very large resort/vacation area, with a large ball room, and likely caters to a crowd of hundreds. Drop bottom pans would be essential for serving a neat looking pie.