Lay down a sheet of newspaper to protect your working surface from any spilled glue.
Sand both broken edges of ceramic or porcelain with fine-grit sandpaper. Sand very lightly, without applying much pressure.
Wipe both broken surfaces clean with a cloth. Apply a thin coat of acrylic-based ceramic adhesive cement to one broken edge only.
Press the pieces together and hold them in place for two minutes.
Tape the glued pieces together with masking tape, and set the object in a position that does not place any stress on the fracture while the glue cures. Allow the glue to cure overnight before moving the ceramic or porcelain object.