RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Serial No.

62/523,057, filed June 21, 2017. The entire contents of the above application are incorporated by reference herein.

FIELD OF THE APPLICATION

[0001] This application relates to dewatering equipment useful for tailings management. BACKGROUND

[0002] Fine materials generated from mining activities are often found well-dispersed in aqueous environments, such as wastewater. The finely dispersed materials may include such solids as various types of clay materials, recoverable materials, fine sand and silt. Separating these materials from the aqueous environment can be difficult, as they tend to retain significant amounts of water, even when separated out, unless special energy- intensive dewatering processes or long-term settling practices are employed.

[0003] An example of a high-volume water consumption process is the processing of naturally occurring ores. During the processing of such ores, colloidal particles, such as clay and mineral fines, are released into the aqueous phase often due to the introduction of mechanical shear associated with the hydrocarbon-extraction process. In addition to mechanical shear, alkali water is sometimes added during extraction, creating an environment more suitable for colloidal suspensions. A common method for disposal of the resulting "tailing" solutions, which contain fine colloidal suspensions of clay and minerals, water, sodium hydroxide and small amounts of remaining hydrocarbon, is to store them in "tailings ponds." These ponds take years to settle out the contaminating fines, posing severe environmental challenges. Tailings ponds or similar liquid retention areas can contain aqueous suspensions of fine particles from mining operations and other industrial operations, for example fine coal particles from coal mining and fly ash from coal combustion, with the potential for environmental damage and catastrophic leakage. It is desirable to identify a method for treating tailings from mining operations to reduce the existing tailings ponds, and/or to prevent their further expansion. Alternatively, suspended fines can be removed from the fluid streams before their confinement in the tailings ponds, but such processes can be time-consuming, expensive, and inefficient, yielding a semisolid material that requires further treatment before it can be stored safely in a dry, stackable state.

[0004] To address these problems in tailings management, treatment systems and methods have been devised that remove suspended particles from fluid streams quickly, cheaply, and with high efficacy, yielding a recovered or recoverable solid material that retains minimal water, so that it can be readily processed into a substance that is mechanically stable; such treatment systems also yield clarified water that can be recycled readily for further industrial purposes. Such systems and methods, termed the Anchor-Tether- Activator (or "ATA") processes, have been described in U.S. Pat. Nos. 8,349, 188, 8,353,641 , 8,557, 123, 8,945,394, and 9,493,367, and in applications related thereto, the entire teachings of which are incorporated herein. The ATA processes provide, in embodiments, various methods of removing particulate matter from a waste tailing fluid, comprising providing an activating material capable of being affixed to the particulate matter wherein the activating material is an anionic or a cationic polymer; affixing the activating material to the particulate matter to form activated particles in the fluid;

providing anchor particles and providing a tethering material capable of being affixed to the anchor particles, wherein the tethering material is a cationic or an anionic polymer; attaching the tethering material to the anchor particles to form tether-bearing activated particles and adding the tether-bearing anchor particles to the fluid, wherein the tethering material attaches to the activated particles to form removable complexes in the fluid; and removing the removable complexes from the fluid, thereby removing the particulate matter from the waste tailing fluid; wherein the fluid is a waste tailing fluid derived from energy production or a mining process; and when the activating material is an anionic polymer, the tethering material is a cationic polymer and when the activating material is a cationic polymer, the tethering material is an anionic polymer; and the anchor particles are larger than the particulate matter.

[0005] As an example, the ATA process can be performed by separately treating a fine and a coarse tailings stream with polymers of opposite electrostatic charges, where one polymer agglomerates the fine stream and the other coats the coarse stream. When these treated streams are then combined, the attraction between the oppositely charged particulate matter in each stream causes the particles in each stream to combine together, allowing for the rapid settling of a consolidated mass that separates rapidly from the water in which it was suspended. As a result, a strong, stackable solid (an "ATA solid") is formed, along with a clear recovered water stream. [0006] In certain cases, the amount of coarse material is low relative to the amount of fine material in the initial fluid streams, i.e., the coarse to fines ratio is low. Under these circumstances, when the treated coarse material is combined with the treated fine material, the resulting solid mass may have a relatively higher moisture level than when there is a more balanced coarse to fines ratio. With higher moisture level, the resultant ATA solid is weak and vulnerable to shear: this lack of structural integrity and shear susceptibility can cause fine particles to be dislodged from the ATA solid under shear conditions, which fine particles can become resuspended in the fluid stream. The presence of fine particles in the fluid stream following shearing of the ATA mass recreates some of the original tailings turbidity, negating some of the benefits produced through the ATA process. In other situations, ATA can be performed as a secondary procedure, after an initial thickening or flocculation has been performed on the fluid stream comprising the fine tailings. In embodiments, techniques as described in the pending patent application USSN 14/312,164 (U.S. Pat. App. Pub. No. US20140377166A1) can be employed for this "reactivation" process.

[0007] While the ATA process has been validated in small scale trials, existing dewatering equipment is not well adapted for processing ATA on a large scale. Current equipment, such as centrifuges, screw classifiers, clarifiers with internal mechanics, vibrating screens, etc., can cause shearing of the ATA solids. This problem is amplified when the ATA solids have a low coarse to fines ratio. As mentioned above, shearing can detach the fine particles from the ATA solids. In addition, sheared ATA solids are not ideal for stacking. Furthermore, large-scale dewatering devices are expensive to manufacture and are expensive to run, due to their power requirements.

[0008] Therefore, there remains a need for a large-scale equipment system that is adapted to the needs of the ATA process. Desirably, the system and methods for its use would permit rapid dewatering of ATA solids, yielding recovered, reusable water and strong, stackable solids without imparting too much shear or energy. Advantageously, the system and methods would have low capital costs and operating costs, in contrast to systems and methods currently available that require expensive equipment with high running costs, making them prohibitively expensive for many applications.

BRIEF DESCRIPTION OF FIGURES

[0009] FIG. 1. is a flow chart depicting a design of a system in accordance with the disclosures herein. [0010] FIG. 2. is a schematic depiction of an embodiment of a separator vessel.

[0011] FIG. 3 is a schematic depiction of an embodiment of a flange design.

[0012] FIG. 4 is a schematic depiction of various embodiments of vessel body designs.

[0013] FIG. 5 is a schematic depiction of an embodiment of a separator vessel.

[0014] FIG. 6 is a schematic depiction of an embodiment of a baffle design.

[0015] FIG. 7 A is a perspective view and FIG. 7B is a schematic depiction of a cross- section of an embodiment of a separator vessel.

[0016] FIG. 8 is a schematic depiction of a cross-section of a separator vessel.

[0017] FIG. 9 is a schematic depiction of a flow path modification for a separator vessel.

SUMMARY

[0018] Disclosed herein are embodiments of a shear-reducing separator vessel, comprising an inlet in fluid communication with a vessel body, the vessel body being in fluid communication with an outlet, wherein a consolidated fluid stream from an ATA process flows through the inlet into the vessel body as a laminar flow stream. In embodiments, the laminar flow stream further separates into a recovered water stream and a separated solids stream within the vessel body. In embodiments, the recovered water stream exits the vessel body through a weir apparatus, and the weir apparatus can be accessed by the recovered water stream through a plurality of water drainage paths. In embodiments, the separated solids stream exits the vessel body through an outlet. In embodiments, the vessel further compromises an additional dewatering apparatus that dewaters the separated solids stream upon its exit from the outlet. In embodiments, there can be one or more baffles within the vessel body. The vessel can further comprise an extended flow path, wherein the extended flow path reduces the shear in the laminar flow stream, and the extended flow path can be of a spiral configuration.

[0019] Further disclosed herein, in embodiments, are methods of forming a dewatered ATA solid, comprising treating a fluid stream comprising fine tailings with an activator polymer to form a first treated stream, treating a fluid stream comprising coarse tailings with a tethering polymer to form a second treated stream, combining the first treated stream and the second treated stream to form a third fluid stream comprising consolidated ATA solids, and processing the consolidated solids through the shear-reducing separator vessel described above and herein, thereby forming the dewatered ATA solid. DETAILED DESCRIPTION

1. System Overview

[0020] In embodiments, the system 101 (represented within the dashed line on the flow diagram in FIG. 1) provides for the separate treatment of a fine particulate stream with a first polymer, Polymer A, and a coarse particulate stream with a second polymer, Polymer B, in mixing vessels, with subsequent combination in a treatment vessel to produce a consolidated solid mass, in accordance with the ATA process, as described in more detail below. The consolidated solid mass the passes into a separator vessel (SV) that is designed to permit rapid settling of the fluid stream passing therethrough, to facilitate the removal of the water in the stream and the consolidation of the solids therein. The separator vessel is designed to minimize the shear experienced by the ATA solids as they are in the process of consolidating. By minimizing shear during consolidation, the SV accelerates the consolidation process and yields a stronger consolidated ATA solid. Further, by minimizing shear, the SV reduces the mechanical disturbance that the consolidated ATA solid encounters during processing, thus reducing any post-consolidation exfoliation of fine particles. The removal of water via the separator vessel can mitigate the susceptibility of the ATA solids to shear downstream, so that pumping or stacking the solids can have less of an impact. In embodiments, the SV does not require power, thus minimizing its cost of operation. In embodiments, the SV can be used in an optional, multi-stage dewatering process using additional dewatering equipment for secondary dewatering, in order to produce the most optimal solids for stacking. The SV is designed to be integrated with the ATA process, so that it receives a fluid stream containing ATA solids after they have been formed via the ATA process. The system 101 is configured to be used with the ATA process to effect dewatering; optionally, its products can be conveyed into separate, secondary dewatering equipment and/or systems to effect further dewatering.

[0021] In an embodiment, separate mixing vessels can be used to treat the fine and coarse streams with the appropriate polymer, and then the treated streams can be combined in a treatment vessel to allow the two treated streams to interact. The configuration of these vessels can be arranged in various shapes and structures by those of ordinary skill in the art. For example, these vessels can be angled mixing boxes with baffles that allow a retention time of between five and ten seconds for the fluid to reside in the vessel.

[0022] As schematically depicted in the flow chart of FIG. 1, to treat the fine stream 103 used in the ATA process, this fluid stream 103 can be agitated in a holding tank (not shown) to keep the fine particles suspended, and then can be pumped to a first mixing vessel 105 where a polymeric treatment agent could be added in metered doses via a pump (not shown). In parallel, the suspended coarse material 107 can be pumped in a vertical sand pump (not shown) along with additional process water that is added in sufficient amounts to create an easily pumpable coarse slurry, for example a slurry of 25-30% solids. This coarse slurry can then be pumped to a second mixing vessel 109, where it is combined with a second polymeric treatment agent that is added in metered doses via a pump (not shown). In an embodiment, the first polymeric treatment can be added at the entrance to the first mixing vessel 105 where the fine stream 103 is introduced. The second polymeric treatment agent can be added at the entrance of the second mixing vessel 109 where the coarse stream 107 is introduced. Emerging from each mixing vessel is a fluid stream 111 and 113 containing agglomerated particles: agglomerated fine particles treated with the first polymeric treatment, and coated coarse particles treated with the second polymeric treatment.

[0023] When the first treated stream 111 (fines) and the second treated stream 113 (coarse) are joined together, they interact to form consolidated particles in a fluid stream

(the final treated stream). These consolidated particles tend to settle spontaneously as soon as they are formed. The combination of the two treated streams can take place in any convenient conduit or vessel, for example a pipe, a treatment vessel 115 (as shown in FIG.

1) or a mixing box, to form a single treated stream 117 wherein the ATA reactions have taken place, as described below in more detail. Once the ATA-driven consolidation has occurred, a SV 119 can be employed to accelerate the settling of the consolidated particles and facilitate dewatering.

[0024] In embodiments, the SV 119 can be introduced into the system as a separate apparatus, or it can be integrated with the final mixing vessel 115 as a single piece of equipment. Optionally, the system 101 can be combined with additional secondary dewatering equipment 121.

2. Separator Vessel Design

[0025] A separator vessel is designed to be integrated into the ATA process system after the initial consolidation of the ATA solids, so that the solids can be separated from the fluid stream and so that they can be protected from shear as they undergo further consolidation through dewatering. It is therefore desirable to protect the consolidated solids from turbulent flow so that they can undergo further, more durable consolidation. Turbulent flow can be defined as a fluid flow that experiences aggressive, irregular movement, and is represented by a Reynold's number above 2000. Below this Reynolds number, laminar flow can occur. Fluids within the laminar regime will undergo less shear than those in the turbulent regime, as laminar flow allows for a more orderly, path-like motion. The Reynold's number can be represented by the following equation EQ1 :

EQ1: Re = ^

μ

Where:

• p is the density of the fluid

• u is the velocity of the fluid

• L is the characteristic length (diameter or width of the flow)

• μ is the dynamic viscosity of the fluid

[0026] As p and μ are inherent in the tailings material itself, these parameters cannot be changed by the design of the SV. The velocity of the fluid as it courses through a conduit and the characteristic length of the conduit can be changed.

[0027] The velocity of the fluid is defined as:

, ,„ _ volumetric flow rate

cross sectional area

[0028] Using a Reynold's number of 2000, one can determine the maximum velocity for specific tailings at a specific flow rate to design the dimensions of the separator vessel. Multiple parameters can be changed, as long as the separator vessel is designed to achieve a Reynold's number below 2000.

[0029] An embodiment of a separator vessel 201 is shown in FIG. 2. In embodiments, a separator vessel comprises an inlet system 202, which may include an inlet port, an inlet orifice, an inlet flange or other inlet mechanism, a vessel body 204, and an outlet or exit port 206. In embodiments, the separator vessel further comprises one or more baffles (not shown in FIG. 2). In embodiments, the separator vessel further comprises an overflow weir (not shown in FIG. 2).

[0030] The inlet system 202 permits the final treated stream of the ATA process (i.e., as described above, the stream previously formed by combining the treated fines stream and the treated coarse stream) to enter the vessel body 204, allowing for a gentle entry of the final treated stream into the vessel to minimize shear. In an embodiment, the inlet system 202 can define an area of fluid communication between a conduit transporting the final treated stream and the vessel body 204. In other embodiments, the inlet system 202 can also be a discrete structure, such as a flange, a port, or some other designated orifice. [0031] When an inlet flange is used as part of the inlet system 202, adjusting the angle and total length of the flange can minimize flow velocity and thereby minimize shear. As would be understood by skilled artisans, a variety of flange angles and lengths may be suitable, depending on the size and other limitations of the process. In addition, the geometry of the flange can be engineered to reduce the linear velocity of the stream as it enters the vessel body 204, for example the flange can be symmetrically widened or otherwise changed in size or shape at or near the intersection of the flange with the separator vessel.

[0032] The exit port 206 allows the consolidated solids to be removed from the vessel body without undergoing undue shear. In embodiments, the consolidated solids can be pumped or drained by gravity through the exit port 206. A gravity drain approach is advantageous for minimizing shear. Gravity draining can occur continuously, by appropriately sizing the separator vessel and the gravity drain port from which the solids are removed. In other embodiments, gravity draining can be timed or otherwise scheduled episodically, for example through the use of an actuated valve, such as a pinch valve, ball valve, or other valve that can cut off flow completely.

[0033] As further shown in FIG. 2, an exit port 206 allows the egress of consolidated solids from the vessel body 204. Exit port 206 positioning can be designed based on the size and shape of the vessel body. In an embodiment, the exit port 206 can be placed at the bottom center of the vessel body 204. The exit port 206 can be placed at the lowest point on the vessel body 204, allowing for an entire built-up bed of solids to exert weight on the solids that are being removed. In addition, this area can have a small cross-sectional area, allowing for the removal of highly dewatered solids. For example, if the walls of the vessel body 204 converge, the exit port 206 can be placed at the point of their convergence. The exit port 206 can also be placed on the side of the vessel body 204. A plurality of exit ports can be used, positioned to facilitate removal of consolidated material. The multiple ports can be formed on the same side of the vessel or they can be positioned on different sides. In an embodiment, an exit port can be made in a circular shape, thereby accommodating a hose connection and minimizing stress on the solids being removed. In other

embodiments, the exit port can be oval shaped or shaped in the form of a polygon.

[0034] FIG. 3 depicts schematically a separator vessel 301 wherein an inlet system 302 is arranged as a flange having parameters that can be adjusted to optimize flow of the final treated stream fluid on a fluid pathway 306 while minimizing shear. A maximum velocity for the fluid determined by Reynold's number can be used in the following equation that relates velocity to the angle of an inclined plane:

Vj ² — v ² = 2gs sin(#)

Where:

Vj is the final velocity

Vi is the initial velocity

g is the acceleration of gravity (9.8— )

s is the total displacement (length)

Θ is the angle of incidence of the inlet system 302 (e.g., a flange) as it intersects with the vessel body 304

[0035] A radius, r, identifies the curvature profile for the intersection of the inlet system's 302 fluid pathway 306 with the vessel body 304. In embodiments, a radius r is selected that allows for the treated slurry on the fluid pathway 306 to enter gently into the vessel body 304. A small radius can cause a more aggressive projection of fluid flow in both the x and y directions. The inlet system 302 (e.g., flange) can be designed in accordance with these principles.

[0036] In an embodiment, the vessel body 304 is designed to minimize shear while permitting the easy removal of consolidated solids. In embodiments, the vessel body 304 can have a tapered design, so that the highest density material can be preferentially removed at the bottom via gravity draining or pumping. A tapered shape can be conical, pyramidal, or any other regular or irregular shape that facilitates the segregation of the consolidated solids without introducing shear stress. For example, the sides can be parallel to each other, or they can be slanted equally or asymmetrically. The tapering can be directed in the x, y, or z directions, or some combination thereof. There can be a straight edge or a tapered edge. The vessel 304 bottom can be flat, rounded, or shaped in any polygonal shape. In embodiments, a separate drop zone for the fluid pathway 306 in the vessel 304 can be created that is distinct from or separate from a consolidation zone that allows consolidation of the solids entrained in the fluid pathway. In an embodiment, to prevent an uneven bed of solids from building up on the inlet side of the vessel 304, the design can have one straight edge and one slanted edge to cause tapering.

[0037] Selected embodiments of vessel body designs are depicted schematically in FIG. 4, illustrating two tapered sides 402 for the vessel, a straight side 404 meeting a tapered side for the vessel, a square bottom 406 for the vessel, and a rounded bottom 408 for the vessel. FIG. 4 also depicts an embodiment of the vessel 410 wherein a consolidation zone 412 is disposed below a drop zone 414, allowing the consolidated solids to settle by gravity out of the fluid stream of treated solids.

[0038] FIG. 5 depicts an embodiment of a separator vessel 501 with representative dimensions.

[0039] Optionally, the separator vessel can contain one or more baffles. The baffle can direct fluid flow for the treated solids and prevent the recovered water from short circuiting and being released before suspended solids have the chance to settle in the vessel. The baffle can sit at a distance from the inlet system or flange, with the optimal distance being determined by EQl above. The baffle can be formed as a rectangular piece installed within the vessel, inserted vertically or horizontally or diagonally, at any length or depth, or attached at any angle. As depicted schematically in FIG. 6, an angled baffle 601 with a concavity is especially advantageous, as an angled baffle 601 can direct flow downwards and impart less shear onto the incident solids. The concavity can also provide the baffle 601 with more surface area, so that the stress from the impact of fluids against it can be distributed more evenly. However, in embodiments, the baffle 601 can be disposed in a convex or a concave direction, along any of the x, y, or z axes as shown in FIG. 6.

[0040] Optionally, the separator vessel can include an overflow weir to collect the recovered water, allowing the recovered water to be discharged into a drain or a hose. In an embodiment, as depicted in FIG. 7 A, water to be recovered from the separation process can exit the separator vessel 701a by flowing over the overflow lip 702a into the weir 704a, from which the water then drains out through the egress port 706a. The weir 704a can be located on the downstream side of the vessel. The weir 704a can wrap around any part of the separator vessel 701a, or can wrap around the entirety. Its cross section can be rounded, square, polygonal or any other shape. The weir 704a can be angled in any direction, and can allow water to run off its sides or edges. As further shown in FIG. 7A, the weir 704a can incorporate a port 706a permitting water egress. In an embodiment, the port 706a can have a circular shape to connect with a hose or other conduit. The port 706a can also be oval or polygonal or any other shape. The weir 704a can have multiple egress ports or no ports at all. FIG. 7B shows a cross-section of the weir 704b showing the intersection of the overflow lip 702b with the side 708b of the separator vessel 701b. In the depicted embodiment, the weir 704b can remove supernatant fluid from within the separator vessel 701b as that fluid passes over the overflow lip 702b to pass through the port 706b at the bottom of the weir 704b. [0041] In embodiments, the separator vessel can be configured as a cylindrical vessel, with a superior inlet disposed centrally in the top of the vessel. A schematic diagram of such a vessel 801 is presented in FIG. 8, viewing the separator vessel 801 as a transverse cross-section from the top down. In such an embodiment, a weir 804 can be disposed circumferentially, or partially around the perimeter of the vessel. In such an embodiment, as the tailings drop into the center tailings inlet 802 located at the top of the vessel, recovered water can be removed 806 as it is separated from the tailing solids within the vessel 801, with the recovered water flowing into the weir 804. Centrifugal forces can also aid in forcing the solids to separate and remain disposed against the walls of the separator 801 , while the water is removed 806 by flowing into the weir 804.

[0042] In an embodiment, an increased path length can be designed into the separator vessel to allow more time for the solids to settle, thereby decreasing the turbidity of the recovered water by diminishing the number of suspended particles present therein. The extended flow pathway can be designed in the form of a circular spiral, or any other configuration that fits within the shape of the separator vessel. An exemplary embodiment is depicted schematically in transverse cross-section in FIG. 9. In a cylindrical separator vessel 901, for example, a flow extender 902 can spiral along the perimeter of the separator, or along the top of the separator, or the flow extender 902 can be disposed in a spiral design within the separator vessel 901. In each of these embodiments, the flow extender 902 serves to extend the conduit for the fluid stream, allowing more time for solids to settle and decreasing turbidity of recovered particles. As shown, the flow extender 902 conveys the fluid stream from a tailings inlet 904 around the periphery of the vessel 901 to enter 906 the vessel interior through an inlet or gap in the wall of the flow extender. In embodiments, other designs of the flow pathway can similarly extend the distance along which the fluid stream can flow. In embodiments, the end of the flow pathway can intersect with a baffle 908 that can further direct the flow of separated solids downward or inward. By extending the flow path, these design features can increase the distance and time for solids to settle, and they can decrease the velocity of the flow, thereby decreasing shear. In embodiments, these design features or additional ones can be deployed decrease shear by allowing a gentler interaction with the walls of the separator vessel or any baffles.

[0043] Additional equipment for secondary dewatering can be introduced following the passage of the final treated stream through the separator vessel. Dewatering equipment such as a belt conveyor, linear screen, or gravity belt thickener can be used to remove any excess water from the previously dewatered solids while imparting little to no shear on them. Solids from the bottom of the separator vessel can be further dewatered after discharging onto one of these pieces of equipment, such as a belt conveyor. The conveyor can further include a filter cloth or a standard, nonporous conveyor belt, where the porosity of the filter cloth is chosen based on the behavior of the solids. If a standard conveyor belt is used, the conveyor can be angled properly to allow excess water to run off as the solids are conveyed. In an embodiment, consolidated solids can be discharged from the separator vessel onto the lowest part of the belt conveyor and can be conveyed upward. Using this technique, the conveyed solids fall off the belt and into an area for stacking or storage. A drip pan with a port can be installed beneath the belt to collect additional water that is removed during this additional dewatering process. A hose connected to the drip pan port can transport this additional water back to the fines tank, via a small pump, in the event any solids are still present that require removal. If sufficiently clear and free of suspended fines, this water can be reused.

[0044] At this stage, secondary dewatering equipment can be employed that may apply more mechanical stress to the consolidated solids, because the ATA solids have been dewatered sufficiently to resist this stress. For example, dewatering equipment such as a screw classifier, trommel screen, vibrating screen, etc. may be used.

3. ATA Process

a. ATA Process Overview

[0045] As described above, the SV disclosed herein is designed to be used in conjunction with the ATA process for tailings treatment, as that process has been generally described in U.S. Pat. Nos. 8,349,188, 8,353,641, 8,557,123, 8,945,394, and 9,493,367, and in applications related thereto, the entire teachings of which are incorporated herein.

[0046] The systems and methods used in the ATA process involve three components: activating the fine particles, tethering them to anchor particles, and sedimenting the fine particle-anchor particle complex. In more detail, the systems and methods used in the ATA process employ three subprocesses: (1) the "activation" of the wastewater stream bearing suspended fine particles ("fines") by exposing this stream to a dose of a flocculating polymer that attaches to the fines, thereby "activating" them; (2) the preparation of tether- bearing anchor particles, where particles coarser than the fine particles, whether obtained separately or obtained from a coarser stream of particles that is produced as part of a mining process ("anchor particles"), are combined with a polymer (a "tethering polymer" or a "tether") selected to complex with the activated fines; and (3) adding the tether-bearing anchor particles to the wastewater stream containing the activated fines, so that the tether- bearing anchor particles form complexes with the activated fines. The activator polymer and the tether polymer have been selected so that they have a natural affinity with each other. Combining the activated fines with the tether-bearing anchor particles rapidly forms a solid complex that can be separated from the suspension fluid, resulting in a stable mass that can be easily and safely stored, along with clarified water that can be used for other industrial purposes. Following the separation process, the stable mass can be used for beneficial purposes, as can the clarified water. As an example, the clarified water could be recycled for use on-site in further processing and beneficiation of ores. As an example, the stable mass could be used for construction purposes at the mine operation (roads, walls, etc.), or could be used as a construction or landfill material offsite. Dewatering to separate the solids from the suspension fluid can take place in seconds, relying only on gravity filtration. As described above, the separation process can be enhanced by using a SV in accordance with the foregoing disclosure,

b. Activation

[0047] As used herein, the term "activation" can refer to the interaction of an activating material, such as a polymer, with fine suspended particles in a liquid medium, such as an aqueous solution. The particles (or "fines") that can be activated are generally fine particles that are resistant to sedimentation. Such particles, for example, can have a mass mean diameter of less than 50 microns or particle fraction that remains with the filtrate following a filtration with, for example, a 325 mesh filter. In embodiments, high molecular weight polymers can be introduced into the particulate dispersion, so that these polymers interact, or complex, with such fine particles. The polymer-particle complexes interact with other similar complexes, or with other particles, and form agglomerates.

[0048] This "activation" step can function as a pretreatment to prepare the surface of the fine particles for further interactions in the subsequent phases of the disclosed system and methods. For example, the activation step can prepare the surface of the fine particles to interact with other polymers that have been rationally designed to interact therewith in an optional, subsequent "tethering" step, as described below. Not to be bound by theory, it is believed that when the fine particles are coated by an activating material such as a polymer, these coated materials can adopt some of the surface properties of the polymer or other coating. This altered surface character in itself can be advantageous for sedimentation, consolidation and/or dewatering. In another embodiment, activation can be accomplished by chemical modification of the particles. For example, oxidants or bases/alkalis can increase the negative surface energy of particulates, and acids can decrease the negative surface energy or even induce a positive surface energy on suspended particulates. In another embodiment, electrochemical oxidation or reduction processes can be used to affect the surface charge on the particles. These chemical modifications can produce activated particulates that have a higher affinity for tethered anchor particles as described below.

[0049] The "activation" step may be performed using flocculants or other polymeric substances. Preferably, the polymers or flocculants can be charged, including anionic or cationic polymers. In embodiments, anionic polymers can be used, including, for example, olefinic polymers, such as polymers made from polyacrylate, polymethacrylate, partially hydrolyzed polyacrylamide, and salts, esters and copolymers thereof (such as (sodium acrylate/acrylamide) copolymers) polyacrylic acid, polymethacrylic acid, sulfonated polymers, such as sulfonated polystyrene, and salts, esters and copolymers thereof, and the like. Suitable poly cations include: polyvinylamines, polyallylamines,

polydiallyldimethylammoniums (e.g., polydiallyldimethylammonium chloride, branched or linear polyethyleneimine, crosslinked amines (including epichlorohydrin/dimethylamine, and epichlorohydrin/alkylenediamines), quaternary ammonium substituted polymers, such as (aciylamide/dimethylaminoethylacrylate methyl chloride quat) copolymers and trimethylammoniummethylene-substituted polystyrene, poly vinylamine, and the like.

Nonionic polymers suitable for hydrogen bonding interactions can include polyethylene oxide, polypropylene oxide, polyhydroxyethylacrylate, polyhydroxyethylmethacrylate, and the like. In embodiments, an activator such as polyethylene oxide can be used as an activator with a cationic tethering material in accordance with the description of tethering materials below. In embodiments, activator polymers with hydrophobic modifications can be used. Flocculants such as those sold under the trademark MAGNAFLOC® by Ciba Specialty Chemicals can be used.

[0050] In embodiments, activators such as polymers or copolymers containing carboxylate, sulfonate, phosphonate, or hydroxamate groups can be used. These groups can be incorporated in the polymer as manufactured; alternatively, they can be produced by neutralization of the corresponding acid groups, or generated by hydrolysis of a precursor such as an ester, amide, anhydride, or nitrile group. The neutralization or hydrolysis step could be done on site prior to the point of use, or it could occur in situ in the process stream. [0051] In embodiments, activator polymers listed in Table 1 are useful in the ATA process:

TABLE 1

[0052] Activator polymers can be introduced at a dosage range of about 20-2000PPM. A similar dosage range is suitable for tether polymers, as discussed below. In embodiments, the ratio of activator and tether polymers of between about 1 : 10 to about 10: 1

Activator: Tether can be employed. While the activator and tether polymers are available in a range of molecular weights, the larger molecular weight polymers may be particularly advantageous. [0053] In certain embodiments, the activated particle can be an amine functionalized or modified particle. As used herein, the term "modified particle" can include any particle that has been modified by the attachment of one or more amine functional groups as described herein. The functional group on the surface of the particle can be from modification using a multifunctional coupling agent or a polymer. The multifunctional coupling agent can be an amino silane coupling agent as an example. These molecules can bond to a particle surface (e.g., metal oxide surface) and then present their amine group for interaction with the particulate matter. In the case of a polymer, the polymer on the surface of the particles can be covalently bound to the surface or interact with the surface of the particle and/or fiber using any number of other forces such as electrostatic, hydrophobic, or hydrogen bonding interactions. In the case that the polymer is covalently bound to the surface, a

multifunctional coupling agent can be used such as a silane coupling agent. Suitable coupling agents include isocyano silanes and epoxy silanes as examples. A polyamine can then react with an isocyano silane or epoxy silane for example. Polyamines include polyallyl amine, polyvinyl amine, chitosan, and polyethylenimine.

[0054] In embodiments, polyamines (polymers containing primary, secondary, tertiary, and/or quaternary amines) can also self-assemble onto the surface of the particles to functionalize them without the need of a coupling agent. For example, polyamines can self- assemble onto the surface of the particles through electrostatic interactions. They can also be precipitated onto the surface, in the case of chitosan for example: since chitosan is soluble in acidic aqueous conditions, it can be precipitated onto the surface of particles by suspending the particles in a chitosan solution and then raising the solution pH.

[0055] In embodiments, the amines or a majority of amines are charged. Some polyamines, such as quaternary amines are fully charged regardless of the pH. Other amines can be charged or uncharged depending on the environment. The polyamines can be charged after addition onto the particles by treating them with an acid solution to protonate the amines. In embodiments, the acid solution can be non-aqueous to prevent the polyamine from going back into solution in the case where it is not covalently attached to the particle.

[0056] The activator polymers and fine particles (whether modified or unmodified) can complex via forming one or more ionic bonds, covalent bonds, hydrogen bonding and combinations thereof, for example. Ionic complexing is preferred.

[0057] To obtain activated fine materials, the activator can be introduced into a liquid medium through several different means, as would be appreciated by those of ordinary skill in the art. For example, a large mixing tank could be used to mix an activating material with tailings from mining operations that contain fine particulate materials. Alternatively, the activating material can be added along a transport pipeline and mixed, for example, by a static mixer or series of baffles. Activated particles are produced that can be treated with one or more subsequent steps of tethering and anchor-separation. c. Tethering

[0058] As used herein, the term "tethering" refers to an interaction between an activated fine particle and an anchor particle, where the anchor particle is treated or coated with a tethering material. The tethering material, such as a polymer, forms a complex or coating on the surface of the anchor particles such that the tethered anchor particles have an affinity for the activated fines. In embodiments, the selection of tether and activator materials is intended to make the solids in the two streams complementary so that the activated fine particles become tethered, linked or otherwise attached to the anchor particles. When attached to activated fine particles via tethering, the anchor particles enhance the rate and completeness of sedimentation or removal of the fine particles from the fluid stream.

[0059] In accordance with these systems and methods, the tethering material acts as a complexing agent to affix the activated particles to an anchor material. In embodiments, a tethering material can be any type of material that interacts strongly with the activating material and that is connectable to an anchor particle.

[0060] As used herein, the term "anchor particle" refers to a particle that facilitates the separation of fine particles. Generally, anchor particles have a density that is greater than the liquid process stream. For example, anchor particles that have a density of greater than 1.3 g/cc can be used. Additionally or alternatively, the density of the anchor particles can be greater than the density of the fine particles or activated particles. Alternatively, the anchor particles are simply larger than the fine particles being removed.

[0061] For example, for the removal of particulate matter with an approximate mass mean diameter less than 50 microns, anchor particles may be selected having larger dimensions, e.g., a mass mean diameter of greater than 70 microns. An anchor particle for a given system can have a shape adapted for easier settling when compared to the target particulate matter: spherical particles, for example, may advantageously be used as anchor particles to remove particles with a flake or needle morphology. In other embodiments, increasing the density of the anchor particles may lead to more rapid settlement. Advantageously, anchor particles can be selected that are indigenous to a particular geographical region where the particulate removal process would take place, or anchor particles may be derived from the tailings management process itself, as described below in more detail.

[0062] Suitable anchor particles can be formed from organic or inorganic materials, or any mixture thereof. In referring to an anchor particle, it is understood that such a particle can be made from a single substance or can be made from a composite. Any combination of inorganic or organic anchor particles can be used. Anchor particles can be prepared as agglomerations of heterogeneous materials, or other physical combinations thereof.

[0063] In accordance with these systems and methods, inorganic anchor particles can include one or more materials such as calcium carbonate, dolomite, calcium sulfate, kaolin, talc, titanium dioxide, sand, diatomaceous earth, aluminum hydroxide, silica, other metal oxides and the like. In embodiments, the coarse fraction of the solids recovered from the mining process itself can be used for anchor particles, for example, coal from coal mining. In embodiments, tailings waste streams may be separated into a coarse stream and a fine stream, with the fine stream being activated to become activated fines, and the coarse stream being used as anchor particles to be combined with the tethering polymers.

Organic particles can include one or more materials such as biomass, starch, modified starch, polymeric spheres (both solid and hollow), and the like. Particle sizes can range from a few nanometers to few hundred microns. In certain embodiments, macroscopic particles in the millimeter range may be suitable. In embodiments, a particle, such as an amine-modified particle, can comprise materials such as lignocellulosic material, cellulosic material, minerals, vitreous material, cementitious material, carbonaceous material, plastics, elastomeric materials, and the like.

[0064] Anchor particle sizes (as measured as a mean diameter) can have a size up to a few hundred microns, preferably greater than about 70 microns. In certain embodiments, macroscopic anchor particles up to and greater than about 1 mm may be suitable. Recycled materials, materials separated from tailings management, or other local mining waste, particularly those materials having strength and stability, are advantageous.

[0065] Anchor particles can be complexed with tethering agents, such agents being selected so that they interact with the polymers used to activate the fines. In one example, partially hydrolyzed polyacrylamide polymers can be used to activate particles, resulting in an activated fine particle with anionic charge properties. Then, a cationically charged tether affixed to the anchor particles will attract the anionic charge of the activated particles, to attach the anchor particles to the activated fine particles. As an example of a tethering material used with an anchor particle in accordance with these systems and methods, chitosan can be precipitated onto sand particles, for example, via pH-switching behavior. In embodiments, various interactions such as electrostatic, hydrogen bonding or hydrophobic behavior can be used to affix an activated particle or particle complex to a tethering material complexed with an anchor particle.

[0066] In embodiments, the anchor particles can be treated with a polycationic polymer, for example a polyamine. One or more populations of anchor particles may be used, each being activated with a tethering agent selected for its attraction to the activated fines and/or to the other anchor particle's tether. The tethering functional group on the surface of the anchor particle can be from modification using a multifunctional coupling agent or a polymer. The multifunctional coupling agent can be an amino silane coupling agent as an example. These molecules can bond to an anchor particle's surface and then present their amine group for interaction with the activated fines. In the case of a tethering polymer, the polymer on the surface of the particles can be covalently bound to the surface or interact with the surface of the anchor particle and/or fiber using any number of other forces such as electrostatic, hydrophobic, or hydrogen bonding interactions. In the case that the polymer is covalently bound to the surface, a multifunctional coupling agent can be used such as a silane coupling agent. Suitable coupling agents include isocyano silanes and epoxy silanes as examples. A polyamine can then react with an isocyano silane or epoxy silane for example. Polyamines include polyallyl amine, polyvinyl amine, chitosan, and polyethylenimine.

[0067] In embodiments, polyamines (polymers containing primary, secondary, tertiary, and/or quaternary amines) can also self-assemble onto the surface of the particles to functionalize them without the need of a coupling agent. For example, polyamines can self- assemble onto the surface of the particles through electrostatic interactions. In

embodiments, the amines or a majority of amines are charged. Some polyamines, such as quaternary amines are fully charged regardless of the pH. Other amines can be charged or uncharged depending on the environment. The polyamines can be charged after addition onto the particles by treating them with an acid solution to protonate the amines. In embodiments, the acid solution can be non-aqueous to prevent the polyamine from going back into solution in the case where it is not covalently attached to the particle. The tether polymer can also be precipitated onto the surface in the case of chitosan for example. Since chitosan is soluble in acidic aqueous conditions, it can be precipitated onto the surface of particles by suspending the particles in a chitosan solution and then raising the solution pH. [0068] In embodiments, polymers such as linear or branched polyethyleneimine can be used as tethering materials. It would be understood that other anionic or cationic polymers could be used as tethering agents, for example polydiallyldimethylammonium chloride (poly(DADMAC)). In other embodiments, cationic tethering agents such as

epichlorohydrin dimethylamine (epi/DMA), styrene maleic anhydride imide (SMAI), polyethylene imide (PEI), polyvinylamine, polyallylamine, amine-aldehyde condensates, poly(dimethylaminoethyl acrylate methyl chloride quaternary) polymers and the like can be used. Advantageously, cationic polymers useful as tethering agents can include quaternary ammonium or phosphonium groups. Advantageously, polymers with quaternary ammonium groups such as poly(DADMAC) or epi/DMA can be used as tethering agents. In other embodiments, polyvalent metal salts (e.g., calcium, magnesium, aluminum, iron salts, and the like) can be used as tethering agents. In other embodiments cationic surfactants such as dimethyldialkyl(C8-C22) ammonium halides, alkyl(C8- C22)trimethylammonium halides, alkyl(C8-C22)dimethylbenzylammonium halides, cetyl pyridinium chloride, fatty amines, protonated or quatemized fatty amines, fatty amides and alkyl phosphonium compounds can be used as tethering agents. In embodiments, polymers having hydrophobic modifications can be used as tethering agents.

[0069] In embodiments, tether polymers listed in Table 2 are useful in the ATA process:

TABLE 2

Chemical Group Product Identifiers

FLOQUAT® (PolyDADMAC, SNF) 4420, FL 4440, FL 4520,

FL 4540, FL 4820, TS 45,

TS 45 SH

MAGNAFLOC® (PolyDADMAC, BASF) LT-7994, LT-7995, LT- 7997, LT-7999, LT 35,

LT 37, LT 38, LT 410, LT

425, LT 510, LT 610, LT

7985, LT 7992, LT 7993

SUPERFLOC® (PolyDADMAC, Kemira) C-587, C-591, C-592, C- 595

PRAESTOL™ (PolyDADMAC, Solenis) 186K, 186KH, 187K,

187KH, 40176

[0070] The efficacy of a tethering material, however, can depend on the activating material. A high affinity between the tethering material and the activating material can lead to a strong and/or rapid interaction there between. A suitable choice for tether material is one that can remain bound to the anchor surface, but can impart surface properties that are beneficial to a strong complex formation with the activator polymer. For example, a polyanionic activator can be matched with a polycationic tether material or a polycationic activator can be matched with a polyanionic tether material.

[0071] In hydrogen bonding terms, a hydrogen bond donor should be used in conjunction with a hydrogen bond acceptor. In embodiments, the tether material can be complementary to the chosen activator, and both materials can possess a strong affinity to their respective deposition surfaces while retaining this surface property.

[0072] In other embodiments, cationic-anionic interactions can be arranged between activated fines and tether-bearing anchor particles. The activator may be a cationic or an anionic material, as long as it has an affinity for the fine particles to which it attaches. The complementary tethering material can be selected to have affinity for the specific anchor particles being used in the system. In other embodiments, hydrophobic interactions can be employed in the activation-tethering system. d. ATA Variations

[0073] In embodiments, the ATA process can be tailored to the specific needs of a tailings management system. As an example, the ATA process can be performed by separately treating a fine and a coarse tailings stream with polymers of opposite electrostatic charges, where one polymer (such as an activator polymer) agglomerates the fine stream and the other (such as a tether polymer) coats the coarse stream. When these treated streams are then combined, the attraction between the oppositely charged particulate matter in each stream causes the particles in each stream to combine together, allowing for the rapid settling of a consolidated mass that separates rapidly from the water in which it was suspended. As a result, a strong, stackable solid (an "ATA solid") is formed, along with a clear recovered water stream.

[0074] The ATA process can be applied to treat a tailings stream by splitting the whole tailings stream into fine and coarse tailings streams, as described above, or can be applied in many other configurations. For example, a tailings stream can be split into a plurality of streams of different size fractions using more than one cyclone or size separating apparatus (e.g. screens, centrifuges, filters, etc). In certain embodiments, the fine and coarse tailings can be generated in different parts of the mining operations, which are operationally and/or spatially separated. For example, the fine tailings can be generated from a cyclone overflow stream on a washing process, and the coarse stream can be derived from flotation underflow from a product recovery circuit. Any combination of fine tailings and coarse tailings can potentially be used in the ATA process, where the fine tailings are treated with a polymer (for example an activator polymer) and the coarse tailings can be used as "anchor particles," to be treated with an oppositely-charged polymer (for example, a tether polymer).

[0075] In other embodiments, the whole tailings stream or one of the separate streams can undergo an initial chemical or mechanical treatment or dewatering prior to use in the ATA process. For example, the fines stream can be first treated by a flocculant and be partially consolidated in a thickener into a thickener underflow stream. This thickener underflow stream can then be managed in the ATA process as if it were fine tailings, where it can then be treated with an activator polymer ("re-activated") and subsequently combined with tether-bearing coarse materials or other tether-bearing anchor particles in the definitive ATA treatment process.

[0076] Other versions of conventional tailings treatment processes can be combined with the ATA treatment process, provided that an initial stream is treated with an activator polymer, and a second stream is separately treated with a second, oppositely charged tether polymer, with the two treated streams being subsequently combined to form a consolidated ATA solid. The solids formed by these ATA variations are suitable for dewatering using the SV described above. EXAMPLE

Materials:

• Activator Polymer A

• Tether Polymer T

• Tailings from silica mine, preseparated into coarse and fine samples.

[0077] Example 1

[0078] A separator vessel was built for a pilot-sized trial conducted to consolidate silica tailings. The solids contents of the fine silica tailings were diluted to 10 wt%, and the coarse tailings had a solids content of 88%. The flow rates of fine tailings and coarse tailings were 5 gpm and 10 lb/min, respectively, so a 2: 1 ratio of coarse to fine solids, on a dry basis, was used. The separator vessel was designed to hold double the flow rate.

[0079] The separator vessel used for this Example had a cube-shaped drop zone and a consolidation zone that was pyramidal in shape. A schematic diagram showing the dimensions and configuration of the separator vessel is provided in FIG. 5. A 1.5-inch circular port was located at the bottom front side of the separator vessel that allowed dewatered solids to drain out by gravity. A hose was connected here, and the egress of the dewatered solids was manually metered with a ball valve. An overflow weir on the downstream side of separator collected the recovered water, which was discharged to drain via rubber hose attached to its egress port, roughly in accordance with the diagram in FIG. 7. The overflow weir was only present on that one side of the vessel. A baffle was present about a third of the way across the separator vessel, about 6 inches deep in the unit. The baffle was a straight, rectangular design that was disposed fully across the separator vessel at a 90° angle from the side walls.

[0080] The separator vessel was integrated into a large-scale ATA process. To perform this process, fines were mixed in a holding tank and pumped to the first mixing box where 200 ppm of Activator Polymer A was added. Coarse material was continually added by hand into a vertical sand pump, along with a predetermined amount of water to create a "coarse slurry" of around 25-30% solids, suitable in rheology for pumping through the system. This coarse slurry was pumped into the second mixing box where it combined with 200 ppm of Tether Polymer T. Both mixing boxes were set in parallel eight feet off the ground at approximately a 25° angle. Each box contained baffles and allowed for five to eight seconds of retention time. In the pilot setup, Activator Polymer A was metered using a peristaltic pump and pumped straight to the entrance of the first mixing box where the fines stream was introduced. Tether Polymer T was metered in the same way, and introduced via a conduit into the entrance of the second mixing box where the coarse stream was introduced. The separately treated streams combined in a third, larger mixing box (also at a 25° angle) with baffles. The discharge from the combination mixing box then entered the separator vessel. No flange was present on the separator vessel, as the third mixing box emptied directly into it.

[0081] On average, separator vessel underflow solids had a solids content of 53 wt%, and the separator vessel overflow had turbidity measurements averaging 54 NTU. Good settling and clear water showed that minimal amounts of shear were taking place, so the flow of the solids was mostly likely not very turbulent. Solids taken out of the third mixing box did settle slightly more quickly that the solids in the separator, qualitatively speaking. When a sample was taken out of the third mixing box, the supernatant water was very clear. This water was visually clearer than the water out of the top of the separator. Very few suspended particles were present, but small differences between the water from the third mixing box and the water from the separator were visible. This is most likely caused by slight amounts of shear, suggesting that the specifications of the separator vessel system can be optimized in future experiments to make the flow more laminar.

[0082] Inputting separator dimensions, flow rates, and properties of the tailings stream into EQ 1, the Reynold's number equation, a Reynold's number of 1,556 was measured. This is within the range where laminar or turbulent flow can be present. A smaller Reynold's number, indicating a more laminar flow, could help to improve the very slight shearing of solids.

[0083] In this Example, solids from the bottom of the separator vessel were further dewatered by discharging onto a belt conveyor. The belt conveyor had a 620 CFM (cubic feet per minute) filter cloth on it (-700 microns). Separator underflow solids discharged onto the lowest part of the belt conveyor and were conveyed upward. The conveyed solids fell off the belt into a collection tote. The underflow from the belt conveyor flowed into a drip pan welded beneath the belt. A hose was connected to a port in the drip pan where the underflow can be transferred back to the fines tank. [0084] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.