Consolidation of slurries of solid particulate materials

An apparatus for removing liquid from a slurry of solid particulate material and for consolidating the solid material into a shape-retaining slug, comprising

• (a) a cylindrical consolidation chamber in which the slurry is to be consolidated, which is substantially sealed against the passage of solid material therefrom, comprising
• (i) a mold comprising a cylindrical wall which defines a cylindrical bore, and
• (ii) two cylindrical pistons extending into opposite ends of said wall, at least one of which is movable axially within said wall,
• (b) a means for filling said chamber with the slurry,
• (c) at least one compression means for reciprocating a piston axially within said chamber and for applying a compressive stress to the slurry in said chamber to cause consolidation thereof,
• (d) at least one drainage means for allowing liquid to escape from said chamber during consolidation of said slurry,
• (e) at least one porous structure for retaining solid particulate material within said chamber and for allowing liquid to escape from said chamber during consolidation of said slurry, said porous structure being disposed between said drainage means and said slurry within said chamber, wherein said porous structure comprises,
• (i) a circular sheet of elastic material having a plurality of holes therethrough, wherein said sheet is disposed relative to one of said pistons so that the holes through said sheet communicate with the drainage means, and
• (ii) two woven wire screens having the same plain weave and the same mesh size, wherein one of said screens is disposed adjacent to said sheet of elastic material, and wherein said screens are disposed relative to each other so that when compressive stress is applied to the slurry in said chamber, the two screens are forced together against said sheet of elastic material so that the portions of the woven wires of one screen which face the other screen at the points where the wires of the first screen cross intimately engage the openings through the other screen, and
• (d) a means for removing the consolidated slug from said chamber.

A process for removing the liquid from a slurry of solid particulate material and for consolidating the particulate material into a shape-retaining slug, comprising

• (a) placing a charge of said slurry in an enclosed consolidation chamber provided with drainage means for escape of the liquid from the chamber,
• (b) interposing a porous structure between said slurry and said drainage means, said porous structure comprising
• (i) a sheet of elastic material having a plurality of holes therethrough, wherein said sheet is disposed in said chamber so that the holes through said sheet communicate with said drainage means, and
• (ii) two woven wire screens having the same plain weave and same mesh size, wherein one of said screens is disposed adjacent to said sheet of elastic material, and wherein said screens are disposed relative to each other so that when compressive stress is applied to the slurry in said chamber, the two screens are forced together against said sheet of elastic material so that the portions of the woven wires of one screen which face the other screen at the points where the wires of the first screen cross intimately engage the openings through the other screen,
• (c) applying compressive stress to said slurry in said chamber, thereby causing said screens to intimately engage, removing liquid from said slurry through said drainage means, and consolidating said slurry into a slug.