Chelation is a well- known old process in industrial chemistry and in the removal of heavy metals from the body. I have a high body burden of Lead because I worked in a Lead Refinery. It ends up in the bone marrow. There are two alternatives - either you allow nature to take it's course and the Lead will eventually pass out through the kidneys. The alternative is chelation which mobilises the Lead and speeds up the process of elimination. The problem can be an overload on the Kidneys causing damage in that organ. That is the issue which must be addressed. Often the metal is "locked away" in the body but chelation releases it, possibly too quickly.
The common chemical used is EDTA [ do you really want to know what that stands for ?