Segmented ceramic liner for induction furnaces

In a furnace comprising an upright shell having top and bottom closure means and containing electric heating mean, thermal insulating means intermediate to the heating means and the shell, and an improved substantially cylindrical liner disposed radially inwardly from the heating means, said liner comprising a plurality of elongated substantially cylindrical ring-shaped liner segments with circumferential inner and outer surface regions and stacked open end to open end upon one another within said shell with end surface regions of adjacently disposed liner segments being disposed in an abutting relationship and with end surface regions at opposite longitudinal ends of each liner segment being disposed in substantially parallel planes, each end surface region of each liner segment having a shaped vertically offset surface portion complementary to a shaped vertically offset surface portion on the end region of an adjacently disposed liner segment for defining a tortuous path between the inner and outer surface regions at the interface between the adjacently disposed liner segments, and with each of said liner segments being of a substantially cellular construction provided by a fiber-free structural form selected from the group consisting of bonded-together hollow ceramic spheres in a ceramic matrix, reticulated ceramic foam, and a ceramic honeycomb and with said structural form being of at least one ceramic material selected from the group consisting of alumina, mullite, partially stabilized zirconia, magnesium oxide, clay, spinel, cordierite, yttrium oxide, zirconia-opacified mullite, and mixtures thereof.