Abstract: A dilute slurry that includes mineral wool fibers, a clay binder, other binders and a flocculent is introduced into a forming tank at several elevations and with sufficient velocity to circulate toroidally therein. A mandrel having the desired configuration of one surface of the shaped article is lowered into the forming tank and rotated at a preselected speed. Vacuum is applied to the rotating mandrel and a substantially uniform layer of solids is deposited on the outer surface of the mandrel while the filtrate is withdrawn through an internal portion of the mandrel and conveyed to a filtrate recovery tank. After a layer of a preselected thickness is deposited on the outer surface of the mandrel, the mandrel is removed from the forming tank and vacuum is maintained on the mandrel to reduce the water content of the accreted fibers to between about 40 to 65% by weight water. Thereafter, while on the mandrel, the accreted fiber-shaped article is trimmed to provide an outer surface of a desired configuration.

Abstract: A mineral wool insulation product containing a major portion of mineral wool fibers, a conventional binder, and predetermined quantities of an admixture of selected colloidal mineral clays to provide an insulation product having extremely low quantities of free silica and excellent physical properties. The colloidal clay admixture comprises selected quantities of kaolinite clays and bentonite clays.