Process and apparatus for handling synthetic gypsum

Abstract

Method and apparatus for converting wet synthetic gypsum from a flue desulphurization process (FGD) to easily handled and metered briquettes by mixing a hydraulic additive such as by-pass dust from a cement kiln with synthetic gypsum and allowing the heat from the resulting hydraulic reaction to reduce the water content of the mixture to a formable consistency without adding external heat to the mixture as it is formed into briquettes.

Description

DESCRIPTION OF THE DRAWINGS

Attached hereto and made a part of this disclosure is the following drawing which is presented by way of illustration and not of limitation:

FIG. 1 is a schematic representation of the method according to the present invention showing the arrangement of equipment and the flow of material.

Claims

1. A process for preparing and handling synthetic gypsum for cement production and like uses comprising the steps of: a) providing synthetic gypsum in a form having a paste-like consistency;b) adding a hydraulic active additive to said gypsum to initiate a hydraulic exothermic reaction to evaporate water in said gypsum;c) allowing said reaction to continue until the surface water on the mixture has been reduced to a level at which the mixture is formable;d) compacting said gypsum when the water content has been sufficiently reduced to allow stable compaction of said gypsum; ande) storing said compacted gypsum for future use or using it in a cement making process immediately.

2. The process of claim 1 wherein the hydraulic active additive is by-pass dust from a rotary cement clinker kiln at a temperature in the range from about 250° F. to about 400° F.

3. The process of claim 1 wherein the mixture is held and allowed to react for a period of 5 to 20 minutes.

4. The process of claim 4 wherein the mixture is held within a mixer.

5. The process of claim 1 wherein the hydraulic active additive is selected from the group consisting of circulated kiln dust, quick lime, dolomitic lime, and cement.

6. The process of claim 1 wherein the compacting takes place in an applied pressing force from 35 to 75 kN/cm.

7. The process of claim 1 wherein the paste-like synthetic gypsum is the product of a flue gas desulphurization process.

8. A process for forming solid objects from wet, paste-like gypsum material comprising the steps of adding an agent to the gypsum to produce an exothermic reaction, allowing the heat from the reaction to dry the gypsum to a formable consistency without using any other means to dry the gypsum, and then forming the gypsum into a solid shape.

9. Apparatus for preparing synthetic gypsum for improved handling and storage comprising: a) a mixer for receiving and retaining a mix of synthetic gypsum and hydraulic active additives;b) a roller press for compacting the mixture produced by said mixer;c) a vibrating screen for receiving compacted synthetic gypsum from said roller press whereby fines from said compacted gypsum may be recycled back through said roller press and the intact compacted gypsum may be transferred to a conveyor for use or storage.