Microwave or otherwise boil water, add dish soap, make a depression in the middle of the pile, and pour in the water as fast as it soaks in. The dish soap helps it absorb into the ground faster and the too hot water kills ants and eggs. If you get enough of it in there, you might get lucky and kill the queen. You can add poisons to this to get them in the pile faster, but I always try the least toxic methods.