The magnetic properties of chrysotile asbestos

Magnetic anisotropy of asbestos fibers

“…For this purpose, the fibers were assumed to be slender cylinders. The anisotropy was then calculated using expression ͑4͒ taking 3.2ϫ10 Ϫ3 and 3.0ϫ10 Ϫ4 for the volume susceptibilities of crocidolite 11,16 and chrysotile, 16 respectively, and Ϫ1.46ϫ10 Ϫ5 and Ϫ1.2ϫ10 Ϫ5 for those of the corresponding media ͑immersion liquids͒. The calculated shape anisotropy was 5.1ϫ10…”

“…Chrysotile, a fibrous silicate from the serpentine group, takes the form of ''scrolled'' sheets ͑with scroll axis parallel to the length of the fibers͒ containing a layer of SiO 4 tetrahedra and an octahedral cation ͑mainly Mg͒ layer. 12,13 Some of the octahedral sites ͑typically less than 2%͒ are occupied by iron, which can be ferric or ferrous.…”

“…15 A significant proportion of iron is also present in the form of magnetite inclusions, 13,14,16 although data obtained from bulk samples may not be applicable to single fibers. Crocidolite, the fibrous form of riebeckite, has a structure consisting of parallel stacks of long ribbons, each containing an octahedral cation layer sandwiched between two silica double chains, and the unit cell is monoclinic.…”

“…Crocidolite, the fibrous form of riebeckite, has a structure consisting of parallel stacks of long ribbons, each containing an octahedral cation layer sandwiched between two silica double chains, and the unit cell is monoclinic. 16 In crocidolite, which has a high iron content ͑typi-cally about 15%͒, 16 the Fe ions are more strongly coupled than in chrysotile, but ferromagnetic ordering does not occur until 30 K. 17 The susceptibility is an order of magnitude higher than in chrysotile (3ϫ10 Ϫ3 ). 12,16 The highly asymmetric structures of chrysotile and crocidolite admit the possibility of magnetic anisotropy.…”

“…16 In crocidolite, which has a high iron content ͑typi-cally about 15%͒, 16 the Fe ions are more strongly coupled than in chrysotile, but ferromagnetic ordering does not occur until 30 K. 17 The susceptibility is an order of magnitude higher than in chrysotile (3ϫ10 Ϫ3 ). 12,16 The highly asymmetric structures of chrysotile and crocidolite admit the possibility of magnetic anisotropy. While the unit cell of chrysotile is not uniaxial, the overall structure can be expected to lead to uniaxial properties, including axisymmetric susceptibility.…”