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US 6,471,767 B1Granted
Process for recycling gypsum-based waste material into readily crushable members for use in the manufacture of cement and crushable members formed thereby
AssigneeAmerican International Materials, Ltd.
InventorJeffrey J. Konczak
Life of this patent
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Abstract
A process for forming crushable, “synthetic” rocks from waste gypsum involves collecting natural and synthetic gypsum waste in the form of flue gas desulfurization (“FGD”). The gypsum waste has a sludge-like consistency and is passed through an extruder where the moisture in the waste gypsum is drawn off and the waste is densified. The removal of moisture is accomplished under vacuum. The densified waste gypsum is extruded through a die to create three-dimensional shapes with preselected aspect ratios.
Claims21
A process for manufacturing portland cement using recycled gypsum, the process comprising:
- (A) preparing a rough grind of lime bearing materials;
- (B) roasting the rough grind to form cement clinker;
- (C) cooling the cement clinker;
- (D) preparing synthetic gypsum rock from gypsum-bearing waste materials by:
- (1) providing a mass of gypsum-bearing waste material having a calcium content of at least about 50% by weight and a moisture content of between about 5% to about 25% by weight;
- (2) dewatering and densifying the gypsum-bearing waste material by passing it through an extruder while draining moisture from the gypsum-bearing waste material;
- (3) forcing the dewatered and densified gypsum-bearing waste material through a configured opening of the extruder to serially form green blocks having a moisture content of at least about 4% by weight, immediately after extrusion;
- (E) mixing the synthetic gypsum rock together with the cement clinker;
- and,
- (F) grinding the mixed synthetic gypsum rock and cement clinker to form a granular portland cement.
7 more elements
Dependencies are inferred from the claim text.