How to Dissolve Black Sand

Put on rubber gloves and set up the hot plate in a well-ventilated area (ideally outdoors or under a fume hood). Place a borosilicate beaker on the hot plate, but do not begin heating it yet.

Pour the black sand into the beaker. Pour concentrated hydrochloric acid into the beaker until the black sand is completely covered (but no more than that). Turn on the hot plate and slowly raise the temperature until the hydrochloric acid is hot, but not boiling (boiling point varies depending on concentration, but concentrated hydrochloric acid has a boiling point of approximately 109 degrees Celsius or 228 degrees Fahrenheit).

Observe the acid turning a yellow color as the black sand dissolves. Pour out the acid into an unheated beaker when the reaction appears to be slowing and replace with fresh hydrochloric acid until the black sand is completely dissolved.

Mix sodium bicarbonate with water in a large plastic container, leaving a small amount of the sodium bicarbonate at the bottom of the container. Pour the hydrochloric acid (with black sand dissolved in it) into the container, making sure not to allow any splashing. Allow the mixture to sit until it stops sizzling and you see a paste at the bottom of the container; add additional sodium bicarbonate if the hydrochloric acid is not sufficiently neutralized. Dispose of the neutralized mixture by pouring it down a drain.