If you have a path made of paving slabs laid in sand and have a problem with ants making nests in the sand, try this.
Mix borax with the sand in the joints. This should kill the ant colonies. Repeat as necessary by sprinkling a sand and borax mixture on the paving slabs and sweeping it into the joints with a stiff broom, using a back and forth motion
You can also mix the borax with flour and sprinkle around your home if you find ants are making homes in you home.
Sprinkle uncooked grits around where you see ants. They will take these back to where the ant hill is, and get large as they get wet or eaten.