I don't think it would be worth the effort when you can buy pre-sterilized white sand in your choice of silica/quartz or coral composition.
Recently, I was having some trouble keeping the pH in one of my planted FW
tanks high enough to keep my apple snails happy. Rather than buy a 25 lb bag of aragonite, I decided to sprinkle crushed clam shells on the surface. I went to the beach and gathered a grocery bagful of white clam shells. At home, I washed them and smashed them into tiny pieces that filled TWO 6 quart pots. I boiled them for 30 min, bleached them overnight, boiled again for 30 min, and let them air dry. It was a bigger PITA than I expected. I had to use all my kitchen pots to boil the shells and my kitchen stunk of bleach. If I had it to over again, I would have bought the aragonite and donated the 20 lbs that I didn't need to my aquarium club auction. I wouldn't even want to think of doing this treatment to sand - especially the amount that you would probably want!
BTW, the clam shells stabilized and raised my pH to a snail-friendly 7.6, but the point is that I probably should have just bought some aragonite.