Reverse osmosis, ion exchange, or synthetic carbons can be used in place of bone char. According to some sources, these methods are, regrettably, much more expensive for the time being, which makes consumer pressure for vegan alternatives even more important.
Pure white sugar is not the only sugar refined in this way. Although it is not white, brown sugar is run through bone char to remove impurities, as is confectioner’s sugar, which is a combination of refined sugar and cornstarch.
When eating refined sugar, although you are not actually ingesting an animal product, the money you pay goes to the sugar company, which ultimately pays the animal industry for bones or bone char. It’s important to keep in mind that the sale of slaughterhouse by-products, including bones, blood and other body parts such as tendons (as in gelatin), helps the animal industry to make money from the disposal of their waste, and thereby stay profitable. As abstract as it may seem, your purchase of sugar (or products which contain sugar) may be supporting the animal industry.
Most of the cow bones used for refining sugar come from Afghanistan, Argentina, India, and Pakistan, and are then sold to plants that turn them into bone char before they are sold in the United States and elsewhere.