The first uses a two stage process. First stage is to print a clay made up almost but not entirely of metal particles. You use a paste extruder, such as this one from thingiverse, loaded with a metallic clay such as this (which evidently sees a lot of use by jewelry makers). Second stage is to fire the piece in a kiln. You end up with a metal piece.
What other materials besides metal would this clay be made up of? What happens to the clay once the piece is fired in a kiln? Would the object change shape/shrink when heated?