Conditioned colloidal silica post impregnant to prevent binder migration

The invention comprises the process for making an inorganic refractory insulation article by forming a fiber mat from a fiber slurry, impregnating the mat with a conditioned colloidal silica composition comprising colloidal silica, acid, aluminum chlorhydrate and water and drying the mat to form the article. The invention further comprises an inorganic refractory insulation article comprising randomly oriented refractory fibers retained by dried colloidal silica uniformly distributed throughout the article and from about 0.001 to about 1.5 weight percent of aluminum chlorhydrate which article is manufactured in accordance with the process.