Know the meaning of the terms calcination and slaking . Take a practice quiz online. Safety and Common Sense Calcium carbonate is about as harmless as harmless gets. Of course, it is possible to hurt yourself, but it seems rather farfetched outside an industrial setting. You shouldn't breath the dust, or eat it by the spoonful, but it is a common ingredient in foods and the principle ingredient in antacids that promote themselves as supplying calcium.
Lime is another matter.
You shouldn't eat it or get it in your eyes. First aid for eyes is to wash with cold water. But don't go overboard. Slaked lime is added to many foods to counteract excess acidity. It is used in pickling, for example.