Importance

Loading Importance Indicators...

Abstract

A process for making a cement and non-asbestos fiber mat on a Hatschek machine having a cylinder vat, a cylinder in the cylinder vat, and a porous surface on the cylinder on which the mat is formed and through which drainage water passes including the steps of introducing a slurry of cement and non-asbestos fibers and clay and poly(ethylene oxide) and water into the cylinder vat, and maintaining a lesser portion of the porous surface in engagement with the cement and non-asbestos slurry than the portion of the surface which is otherwise normally engaged by a cement and asbestos slurry of the same depth to thereby form the cement and non-asbestos fiber mat on the lesser portion of the porous surface and thus provide a lesser area for the slurry to drain than the area through which a cement and asbestos slurry drains, the poly(ethylene oxide) and clay causing the drainage water to be substantially clear and not to have any appreciable amount of cement fines, the cement and non-asbestos fiber mat containing Portland cement binder in the amount of between about 40% and 80% by weight, natural and/or synthetic fibers in an amount of between about 1% and 15% by weight, clay in an amount of between about 2% and 15% by weight, and poly(ethylene oxide) homopolymer in an amount of between about 0.03% and 0.5% by weight. The product may also contain silica and/or filler in an amount of between 10% and 40% by weight. The silica is generally used in a product which is to be autoclaved. The filler may be waste fiber-cement product or inert filler material.

Loading the Abstract Image...

First Claim