The phrase "bone char" refers to a substance made from animal bones that is used for various purposes, such as filtering and decolorizing sugar or producing carbon for filters. Full definition
Since sugar isn't processed with bone char in Australia, it should be safe! (veggieful.com)
I've found the «vegan» sugar (isn't processed using bone char) to be sweeter than the processed sugar so would I have to use less of it? (namelymarly.com)