| 摘要 |
1424214 Tobacco smoke filter M J O SIREN 19 March 1973 [20 March 1972] 13046/ 73 Heading A2C [Also in Division Cl] A tobacco smoke filter for removing cadmium and cadmium compounds from gas streams comprises a gas permeable mass and a free powdery calcium salt substantially free from cadmium. The gas permeable mass may comprise cellulose or cellulose acetate. The calcium salt may be calcium sulphate, calcium phosphate or calcium carbonate and may be used in an amount of 1-75% 'by weight in the filter. It may be introduced into the permeable mass by suspension in a volatile organic solvent which suspension is introduced into the mass and the solvent allowed to evaporate. Alternatively it may be suspended in a stream of air which is passed through the permeable mass. The mass may contain between 5-8 per cent by weight of calcium salt. |
