TRIBOSTATIC SEPARATION SYSTEM AND METHOD

Field of the Invention The present invention relates to material separating systems and methods.

Specifically, the present invention is a device for separating material by specific gravity and particulate diameter.

Background of the Invention Material such as coal may be mined in highly impure form, and refinement is an implicit step in the process of preparation for consumer use. With relatively inexpensive items such as coal, the cost of such refinement is a major factor on both price and profitability, and so there is an ongoing need to find better and less expensive ways to accomplish such refinement.

Summary of the Invention

A method for separating contaminants from mined coal includes grinding the coal into a gangue of predetermined particle size. The gangue is delivered to a chamber containing substantially inert gas, such as nitrogen, air, or the like. The gangue is induced with a tribostatic charge, which spatially distributes the particles of the gangue by density. In an optional embodiment, the distribution of the particles may be aided by vibrating the gangue in the chamber and/or generating an upward flow of inert gas through the gangue in the chamber. Particles corresponding to the density of coal from the gangue are separated from the remaining gangue.

In an optional embodiment, a method according to an embodiment of the present invention may further include monitoring the oxygen level in the chamber and displacing oxygen with inert gas to maintain the oxygen level in the chamber at a predetermined level. A system for separating contaminants from mined coal according to an embodiment of the present invention may include a hopper holding mined coal in the form of a gangue of predetermined particle size. A chamber containing a substantially inert gas communicates with the hopper. In an optional embodiment, the system includes an oxygen monitor in the chamber monitoring the oxygen level in the chamber. An inert gas source communicates with the chamber. In one such optional embodiment, the inert gas source controls the flow of inert gas to the chamber to displace oxygen with inert gas to maintain the oxygen level in the chamber at a predetermined level. The hopper delivers the gangue to the chamber. Optionally, a gas-saving gate is disposed between the chamber and the hopper. In an optional embodiment, the hopper delivers the gangue to a separating bed in the chamber. In one such optional embodiment, the separating bed is a moving conveyor. Optionally, the separating bed is inclined and the system may include an incline control controlling an incline actuator to adjust the incline of the separating bed. A charge inducer within the chamber induces the gangue with a tribostatic charge, which spatially distributes the particles of the gangue by density within the chamber. For example, in an optional embodiment including a conveyor, a charge inducer is disposed proximate the conveyor.

Optionally, the system further includes a vibrator in contact with the separating bed, that vibrates the gangue on the separating bed. Additionally or

alternatively, the system includes a fan vertically below the separating bed that generates a substantially vertically upward flow of inert gas through the gangue carried by the separating bed.

A transport receives particles having a density corresponding to coal from the distributed particles of the gangue. In one optional embodiment, the transport is a pipe. For example, in one such optional embodiment, the pipe includes a filter that separates the coal particles from the inert gas and any non-coal particles. In another optional embodiment, the transport is an auger.

Brief Description of the Drawings

FIG. IA is a side view of a system according to an embodiment of the present invention;

FIG. IB is a side view of a system according to the embodiment of FIG. IA with the a conveyor at a different incline; FIG. 2 is a front perspective view of a system according to an embodiment of the present invention;

FIG. 3 is a back perspective view of a system according to an embodiment of the present invention;

FIG. 4 is an exposed view of the drawing of FIG. 3; FIG. 5 is a side perspective view of a hopper and gate according to an embodiment of the present invention;

FIG. 6 is a flow chart of a method according to an embodiment of the present invention.

Description

Reference is now made to the figures wherein like parts are referred to by like numerals throughout. Referring generally to FIGS. IA, IB, and 2—5, the device is directed to separating a material into components. The material to be separated is ground (optionally using a grinder) to a predetermined particle size. The gangue is delivered to an inert gas chamber 1 through a delivery system. For example, in the optional embodiment of the figures, the delivery system includes an input hopper 13 delivering gangue to the chamber 1. The input hopper 13, in turn, receives gangue from a feed hopper 9 propelled by a feed screw and motor 3. In the optional embodiment illustrated, the gangue is ground to -200 mesh. In alternate embodiments, other grind sizes may be employed. Optionally, the gangue is mixed with an inert gas provided through an inert gas input pipe 1 1 before or after introduction into the chamber 1. The inert gas may take any form, including air, nitrogen, or other inert gas.

Optionally, gangue loaded through the input hopper 13 passes through a gas- saving gate assembly 14, which prevents inert gases and other contents of the inert gas chamber 1 from escaping. In certain applications, such as when the gangue includes coal or other combustible material, excess oxygen may increases the risk of combustion or explosion in the chamber 1. In an optional embodiment of such an application, oxygen sensors may be installed within the inert gas chamber 1 to monitor the level of oxygen. When the level of oxygen exceeds a predetermined limit, inert gas may be introduced through an inert gas input 11 to displace oxygen, thereby reducing the oxygen level.

The gangue loaded through the input hopper 13 is delivered to a separating bed 16. In an optional embodiment, the separating bed is a conveyor, such as a hollow chain pin assembly helt, that carries gangue through the chamber 1. A linear

actuator 12 induces a tribostatic charge to the gangue as it passes through the chamber 1. The tribostatic charge causes the components of the gangue to separate spatially according to the density of the component, with denser materials separating spatially from less dense materials. For example, in the illustrated system, the denser materials separate to one portion of the chamber 1 and, consequently, will be removable from that portion of the chamber 1.

Removal of material may be accomplished by any type of transport, such as belts, conveyors, or the like. In the optional embodiment shown, material is removed by augers, with a heavy material auger 7 for denser material and a light material auger 6 for less dense material. For example, in one optional embodiment, the desired material, such as coal, is a less dense material. In such an optional embodiment, the less dense materials are extracted at a front auger, and may also be carried along with inert gas out of the chamber 1 through a return pipe 2. The materials carried with the inert gas are optionally filtered from the inert gas through an extracted product filter unit 10 in communication with the return pipe 2. In an optional embodiment, the removed product may be briquetted with a substrate and prepared for consumption. The extracted product filter unit 10 may be self cleaning, such as through pulse cleaning or other cleaning method, or may be cleaned manually. It is noted that the process could be repeated on the remaining gangue, i.e. the gangue remaining after the desired components have been separated, to remove any remaining desired components. In other words, as the remaining gangue may still be rich in one or more desired components, remaining gangue may be recirculated one or more times through the device to remove any desired products

remaining in the gangue. Optionally, the gangue may be reground before being reintroduced to the separating bed.

As shown in FIGS. IA and IB, the slope or incline of the separating bed 16 may be adjustable to control the rate of separation of the gangue. For example, it is known that tribostatic separation rates may be affected by moisture. In an optional embodiment, humidity/moisture sensors may be included in the chamber 1. Optionally, the humidity/moisture sensors communicate with a controller to control the slope or incline of the separating bed 16 within the inert gas chamber 1, thereby controlling the rate of separation. Additionally or alternatively, where the separating bed 16 is a conveyor, speed controls 22 (as shown in FIG. 4) may be implemented to control the rate of movement of the separating bed 16.

In an optional embodiment, as shown in FIG. 4, within the inert gas chamber 1, the hollow pin chain assembly 16 may be enclosed within a dust containment cover 23. The inert gas is pumped into the inert gas chamber 1 through an inert gas intake pipe 11 , and into the enclosure within the dust containment cover 23 through an intake vent 21. Output from the separation is then extracted from the enclosure formed by the dust containment cover 23 through a light product return pipe 20. FIG. 5 illustrates an optional embodiment of an input hopper 13 and gas- saving gate assembly 14. In this optional embodiment, the input hopper 13 includes a paddle auger 29 serves to separate the gangue and prevent clumping. Additionally, a paddle auger 29 may be configured to spread the gangue across an entrance aperture 27 to a rotating seal 26 within a rotating gate 25. The gangue of such an optional embodiment is carried by the rotating gate 25 to an exit aperture 28, through which the gangue exits the rotating gate 25 to the separating bed 16 in the chamber

1. As may be appreciated, the rotating gate 25 is adapted to reduce the inert gas escaping from the chamber 1 through the exit aperture 28.

In an optional embodiment, a fan (not shown) may be installed under the separating bed 16 directing an upward flow of inert gas through the gangue. In one such optional embodiment, a flow distributor may be installed between the separating bed 16 and the fan. For example, in an optional embodiment, a perforated membrane with a plurality of holes distributes the flow of inert gas through the separating bed 16. In another optional embodiment, gas equalization plates may be installed between the separating bed 16 and a fan. In yet another optional embodiment, the separating bed 16 may vibrate to agitate the gangue.

In an optional embodiment, camera monitoring and computerized belt control may be implemented to monitor operation of the device.

Referring to FIG. 6, the present invention also includes a method for separating a material. In an optional embodiment of a method according to the present invention, material to be separated is ground 100 into a gangue of predetermined particle size and delivered to a chamber. Optionally, the chamber contains inert gas. In one such optional embodiment, the oxygen level in the chamber may be monitored and inert gas may be introduced to displace oxygen in the chamber to maintain a predetermined oxygen level. The gangue is induced 200 with a tribostatic charge. Optionally, the tribostatic charge is imparted to the gangue while on a separating bed. The components of the gangue separate spatially according to density. Optionally, the gangue may be vibrated and/or a flow of inert gas may be directed through the gangue to aid in the separation caused by the tribostatic charge.

The particles are extracted 300 according to density. It is contemplated that the particles removed may comprise substantially desired material, thereby leaving behind substantially undesired material, or the particles removed may comprise substantially undesired material, thereby leaving behind substantially desired material. In either case, if additional particles are to be extracted 400, the process may be repeated until the material is substantially separated 500.

While certain embodiments of the present invention have been shown and described it is to be understood that the present invention is subject to many modifications and changes without departing from the spirit and scope of the claims presented herein.