Sand filtration

Hello!! Actually, I am interested in generating pores in sand filter column during manufacturing. It is not the conventional sand filter. I am planning to make a solid sand column by fusing (vitrifying) sand at high temperature. I want to add some sugar in it to produce pores. Can anyone tell me or guide me about the relation of pores generated with the amount of sugar used? Or any other method to generate porosity in such types of solid sand filter.  Thank you!!