Raschig rings made from borosilicate glass. They are used inside vessels and tanks containing solutions of fissile material, for example solutions of enriched uranyl nitrate. There they act as neutron absorbers to prevent a criticality accident.
Raschigs are available in a range of thicknesses of 0.2mm to 1.5mm depending on the size of your raschig rings. you can stack these glass rings inside of your packable column including our High-Efficiency Distillation Head for those doing fractional distillation or other chemical separations