https://www.thespruceeats.com/is-sugar-i-e-granulated-sugar-aka-white-sugar-vegan-4847070

one step in the process of refining cane sugar involves passing it through a charcoal filter to remove impurities, essentially to whiten it. And this charcoal is sometimes made from something called bone char, which is literally the charred bones of animals, mostly cattle and pigs