CROSS-REFERENCE TO RELATED APPLICATIONS

None.

FIELD OF THE INVENTION

This application pertains to industrial filtration equipment applicable for use in the chemical, waste-water treatment, pulp and paper, and mining industries (e.g.. concentrator operations, mineral concentrate filtering, ore dressing, tailings management, and mineral processing).

Particularly disclosed are embodiments of a novel system and method for economically pre-coating filter media to extend filter media life and improve operational efficiency of a filtration process. Pre-coating techniques disclosed herein may be adjusted using various process controls to affect filter cake moisture, cake density, filtration cycle speed, or another characteristic of a filtering process.

Embodiments of the system and method may employ a control system and/or loop feedback techniques through the provision of sensors, and control mechanisms to automatically making predictive and adaptive changes to pre- coating operations within a filtration process, based on real-time information gathered from online sensors and historical data from past observations.

Filtration operations may realize an immediate benefit from practicing embodiments of the invention, which are aimed towards improving vacuum and pressure filtration processes. Embodiments of the invention may promote economic dewatering of feed slurries by increasing operating efficiencies (i.e., reducing operating expenditures OPEX) and increasing consumable filter media wear fife without incurring significant capital expenditure (CAPEX). Embodiments may further promote cake release and reduce occurrences of filter cake product sticking to fitter media, without limitation. industrial operations having one or more filters, or one or more banks of filters may especially recognize advantages through the provision, employment, and/or operational use of embodiments of the pre-coating system and method disclosed herein, it will become apparent from this disclosure that practicing any number of the method steps or system configurations described herein might offer various advantages and benefits not yet available with conventional filtration technologies.

BACKGROUND OF THE DISCLOSURE industrial filters may use vacuum or pressure to de-liquor or extract liquids from slurry material and form a filter cake product These filters may include, for example, drum filters, pan filters, disc filters, filter presses, and the like, without limitation.

Pre-coat filters are industrial filters which employ a layer of pre-coat media {e.g., diatomaceous earth, sand, periite, or other suitable media) to filter media. The pre-coat media forms a barrier between slurry to be dewatered, and the filter media used with a filter. Filter media may generally comprise, without limitation, a cloth, a woven sheet, non-woven sheet, a fine screen, a fine mesh, wedge wire, a combination thereof, or the like, without limitation. The idea behind using pre-coat media is to improve filter media life, and to reduce occurrences of occlusion of the filter media with small particles within the slurry to be dewatered (i.e.. reduce "blinding" of filter media). Drum filters typically apply a pre-coating of pre-coat media to a filter media. The fitter media is provided as a continuous loop. The filter media is supported by a rotating porous cylindrical drum surface. The pre-coat media serves as a harrier layer between an outer surface of the filter media and slurry to be dewatered by the drum filter. The pre-coat media serves as a sacrificial barrier which "protects* the actual filter media from damage by serving as a first filtering surface which can capture fines in the slurry to be dewatered.

By virtue of a vacuum provided to an inside portion of the drum, filtrate passes through the pre-coat layer, the filter media, and then the drum, and is removed from the drum filter. As the drum rotates, filter cake is formed over the pre-coat layer, and a scraper blade removes filter cake solids {from dewatered slurry), and a portion of the pre-coat layer to form a fresh outer filtering surface to which new slurry to be dewatered can be applied. A problem with existing practice, is that material for pre-coatings (i.e., pre-coat media) must be purchased as a consumable. Aside from its fiscal drawbacks, the use of pre-coat media may negatively affect downstream processes, may contaminate filtrate, may cause dust hazards, may need to be stored when new, and may need to be disposed of once it has been used.

Filter presses (such as horizontal automatic filter presses) use pressure, rather than vacuum, and are used in separation processes - specifically to separate solids and liquids. The filtration process for a filter press uses the principle of "pressure driving* by a slurry pump. Filter presses have many uses in the industrial, chemical, pharma, and wine-making industries. They may be utilized to separate water from mud or to dewater tailings and/or mineral mining slurries, without limitation, in some instances, filter presses may be utilized to dewater mineral concentrates, and may be configured as a pre-coat filter.

Types of filter presses may include plate and frame filter presses, automatic filter presses, and recessed plate and frame filter presses. Filter presses can come in various configurations, such as in vertical and horizontal configurations, with horizontal being the most widely used. Three main process characteristics of filter presses include feed, operation, and efficiency.

Filter presses have, in the past, employed the practice of providing pre-coat media to filter media therein. This is generally accomplished by iterative pre-coat cycles, wherein one or more valves are used to alternate between a feed of pre- coat media and slurry to be dewatered. The pre-coat media enters filtration chambers first, to coat filter media, and then the slurry to be dewatered is subsequently introduced.

However, such practice effectively reduces filtration chamber size (by virtue of pre-coat media occupying some of the filter chamber volume, leaving less room for slurry to be dewatered within filtration chambers of a filter press). Moreover, as with drum, pan, disc, and other industrial filters, pre-coat media must be continually purchased, transported, stored, disposed of, and provided to the filtration process as a consumable. This significantly increases operational expenditures (i.e., OPEX costs) and reduces filtering capacity and filtration efficiency.

Media blinding can be caused by small particulates becoming trapped in porosities of filter media (e.g., migrating within a weave of the filter media), thereby effectively reducing the si2e of filter media apertures. This reduction in filter media aperture size restricts flow and impedes the filtrate from flowing through the filter media. Once fine particulates are trapped within the filter media, the fine particulates are extremely difficult to remove, and they will tend to cause agglomeration of additional particles within the apertures of the filter media.

Once the media becomes completely plugged, filtrate cannot flow through the media - a condition associated with filter media blinding. Blinding generally leads to the production of wet, "out-of-spec" filter cake products. Hits blinding problem is being seen especially with tailings filtration operations, since particle size distributions of tailings slurries are extremely gradated (e.g., with p80's typically exceeding 120 microns and/or the p10's typically getting as low as 2-5 microns), without limitation. Previously, filter media blinding has not been consistently recognized or addressed within the filtration arts, because the filters have been used on minerals concentrates, which typically have a narrower particle size distribution. That is, filter presses using filter media designed for use with minerals concentrate slurries are quickly incapacitated from blinding when dewatering minerals processing tailings.

While various solutions have been proposed in an attempt to overcome problems regarding filter media life and filtration efficiency, there still exists a need for filtration technologies which might improve media life and maintain or improve filtration efficiency without necessarily employing the use of expensive pre~coat media consumables.

OBJECTS OF THE INVENTION it is, therefore, an object of the invention to circumvent the aforementioned drawbacks associated with applying pre-coatings of pre-coat media to industrial filters including, but not limited to pre-coat filters.

In particular, it is an object of the invention to enable an industrial filter to produce qualify filter cake and/or filtrate products, and meet target cake specifications, in an efficient manner. it also an object of the invention to improve the life of filter media used with industrial filters - in part, by preventing or limiting ingress of particulate into filter media apertures (e.g., preventing fines from getting trapped in a weave of a filter cloth, without limitation). !t is a further object of the invention to enable conversion of industrial filtration systems (including those which might not comprise pre-coat filters), by retrofitting them to accommodate the inventive pre -coating concepts discussed herein.

This and other objects of the invention will be apparent from the drawings and description herein. Although every object of the invention is believed to be attained by at least one embodiment of the invention, there is not necessarily any one embodiment of the invention that achieves all of the objects of the invention.

BRIEF SUMMARY OF THE INVENTION

A method for pre-coating filter media of a filter (108) is disclosed. The method may comprise the step of performing a separation on a first portion of slurry (102) to be dewatered by the filter (108). The method may further comprise the step of producing a coarse stream (102c) from the separation. The method may further comprise the step of providing at least a portion of the coarse stream (102c) to the filter (108) to pre-coat the filter media of the filter (108). The at least a portion of the coarse stream (102c) may be provided to the filter (108) before providing a second portion of the slurry (102) to the filter (108) for dewatering.

In some embodiments, the first portion of the slurry (102) may comprise a slipstream (102b), without limitation. In some embodiments, the second portion of the slurry (102) may comprise a main stream (102a), a fines stream (102d) produced from the separation, or a combined stream (102e) thereof, without limitation. in some embodiments, the separation may comprise a size separation performed using a classification device (109). In some embodiments, the classification device (109) may be selected from the group consisting of: one or more screens, one or more cyclones, one or more so!id-soiid separation devices, one or more classifiers, one or more reflux classifiers, and a combination thereof, without limitation. In some embodiments, the at least a portion of the coarse stream (102c) may be provided to a holding tank (105) before being provided to the filter (108), without limitation.

In some embodiments, the at least a portion of the coarse stream (102c) may be provided to the filter (108) by virtue of a valve (104b), such as a control valve, without limitation.

A method of dewatering slurry (102) using a filter (108) is also disclosed. In some embodiments, the method may comprise the step of separating a first portion of the slurry (102) into a coarse stream (102c) and a fines stream (102d) using a classification device (109). The method may also comprise the step of providing at least a portion of the coarse stream (102c) to the filter (108). The method may further comprise the step of coating filter media of the filter (108) with the at least a portion of the coarse stream (102c) to form a pre-coat layer on the filter media. The method may further comprise the step of providing a second portion of the slurry (102) to the filter (108) - for example, after coating the filter media of the filter (108) with the at least a portion of the coarse stream (102c). The method may further comprise the step of filtering the second portion of the slurry (102) through the pre-coat and filter media. in some embodiments, the first portion of the slurry (102) may comprise a slipstream (102b). In some embodiments, the second portion of the slurry (102) may comprise a main stream (102a) of slurry (102), without limitation, in some embodiments, the second portion of the slurry (102) may comprise a fines stream (102d) leaving the classification device (109), without limitation. In some embodiments, the second portion of the slurry (102) may comprise a combined stream (102e) comprising a portion or ail of the fines stream (102d) and a portion or all of the main stream (102a), without limitation. In some embodiments, the main stream (102a) may be combined with the fines stream (102d) in a holding tank (103) to form said combined stream (102e), without limitation. in some embodiments, the classification device (109) may be selected from the group consisting of: one or more screens, one or more cyclones, one or more so!id-so!id separation devices, one or more classifiers, one or more reflux classifiers, and a combination thereof, without limitation. in some embodiments, the at least a portion of the coarse stream (102c) may be provided to a holding tank (105) before being provided to the filter (108), without limitation. In some embodiments, the at least a portion of the coarse stream (102c) may be provided to the filter (108) by virtue of a valve (104b), such as a second valve, without limitation. In some embodiments, the second portion of the slurry (102) may be provided to the filter (108) by virtue of a valve (104a), such as a first valve, without limitation.

At times, the valves (104a, 104b) may be closed at the same time. At times, the valves (104a, 104b) may be open at tile same time (e.g., to feed a blend of coarse (102c) and fine (102d) streams to a filter (108) at the same time) during a filtration cycle, without limitation. However, in some preferred embodiments, only one of the valves (104a, 104b) may be open at a particular time during pre- coating and filtration. in some embodiments, the step of providing the at least a portion of the coarse stream (102c) to the filter (108) may comprise opening a second valve (104b) to increase flow of the at least a portion of the coarse stream (102c) to the filter (108); and/or said step may comprise closing a first valve (104b) to reduce flow of the second portion of the slurry (102) to the filter (108), without limitation. in some embodiments, the method may comprise the step of assigning at least one cut-off point to the classification device (109). The at least one cut-off point of the classification device (109) may be set using means for automatically or manually setting and/or adjusting at least one cut-off point. The at least one cutoff point may comprise a threshold which reduces the occurrence of fines in the at least a portion of the coarse stream (102c). According to some embodiments, the method may involve setting the at least one cut-off point to a value which is approximately equal to or greater than an average opening size of the filter media, without limitation. According to some embodiments, the method may comprise adjusting or re-setting the at least one cut-off point, without limitation.

A filtration system (101) for use in a filtration process is further disclosed, in some embodiments, the filtration system (101) may comprise: a filter (108) having filter media; means for receiving infeed slurry (102); means (109) for performing a size separation on a portion of the infeed slurry (102) to produce a coarse stream (102c); means for conveying at least a portion of the coarse stream (102c) to the filter (108) to pre-coat the filter media; and, means for conveying the infeed slurry (102) to the filter (108) after the filter media of the filter (108) has been pre-coated.

In some embodiments, a filtration system (101) for use in a filtration process may comprise a fitter (108) having filter media. The filtration system (101) may further comprise an inlet for receiving infeed slurry (102). The filtration system (101) may further comprise a main stream (102a) operatively connected to the inlet, wherein the main stream (102a) may be in operative communication with the filter (108). The main stream (102a) may be configured to feed the filter (108).

A slipstream (102b) may stem from the main stream (102a), and a classification device (109) may be operatively connected to the slipstream (102b). The filtration system (101 ) may further comprise a coarse stream (102c) stemming from the classification device (109). The at least a portion of the coarse stream (102c) may be in operative communication with the filter (108) and may be configured to feed the filter (108) to pre-coat the filter media. A fines stream (102d) stemming from the classification device (109) may further be employed with the filtration system (101 ). The filtration system (101) may further comprise means for conveying the at least a portion of the coarse stream (102c) to the filter (108) to pre-coat the fi!ter media of the fitter (108), and means for conveying the infeed slurry (102) to the filter (108) after the fitter media has been p re- coated, without limitation. in some embodiments, the main stream (102a) of the filtration system (101) may be configured to feed the filter (108) intermittently, for example, via a first valve (104a), without limitation, in some embodiments, the at least a portion of the coarse stream (102c) of the filtration system (101 ) may be configured to feed the filter (108) intermittently, via a second valve (104b), without limitation. in some embodiments, the filtration system (101) may comprise means for automatically or manually setting and/or adjusting at least one cut-off point of the classification device (109). The at feast one cut-off point may comprise a threshold which reduces the occurrence of fines in the at least a portion of the coarse stream (102c). It may be set to a value which is approximately equal to or greater than an average opening size of the filter media, without limitation.

A retrofit Wt for a filtration system (1, 101) may comprise means (102b) for separating slurry (102) from a main stream (102a) of slurry (102). in some embodiments, the retrofit kit may comprise means (109) for performing a size separation on the slurry (102) separated from the main stream (102a) and for producing a coarse stream (102c). The retrofit kit may further comprise means for conveying at least a portion of the coarse stream (102c) to the filter (108) to pre-coat filter media associated with the fitter (108), without limitation.

In some embodiments, the retrofit kit may comprise means (107b) for conveying the slurry (102) separated from the main stream (102a) to said means (109) for performing a size separation, without limitation, in some embodiments, the retrofit kit may comprise means (104c) for increasing or decreasing flow to the means (109) for performing a size separation, without limitation, in some embodiments, the retrofit kit may comprise means (105) for receiving and/or holding the at least a portion of the coarse stream (102c), without limitation, in some embodiments, the retrofit kit may comprise means (104b) for controlling delivery of the at least a portion of the coarse stream (102c) to the filter (108), without limitation.

In some embodiments, a method of pre~coating filter media of a filter (108) as substantially shown and described may be practiced, in some embodiments, a filtration system (101) as substantially shown and described herein and in the appended drawings may be provided, used, designed, offered for sale, built to a custom specification, or otherwise practiced. In some embodiments, a portion of the disclosed filtration system (101) may be provided as a retrofit kit to improve a conventional filtration system.

In some embodiments, the retrofit kit may comprise means for automatically or manually setting and/or adjusting at least one cut-off point of the classification device (109), threshold. The at least one cut-off point may reduce the occurrence of fines in the at least a portion of the coarse stream (102c) and may be set to a value which is approximately equal to or greater than an average opening size of the filter media, without limitation.

In some embodiments (e.g., FIG. 3), tile at least a portion of the coarse stream (102c) may comprise a refined coarse stream (102f). The refined coarse stream (102f) may be produced by taking a fine solids fraction of the coarse stream (102c) in a second separation step (e.g., comprising a second classification device 109), without limitation.

BRIEF SUMMARY OF THE DRAWINGS

To complement the description which is being made, and for the purpose of aiding to better understand the features of the invention, a set of drawings illustrating new and novel methods and apparatus for improving industrial filtration processes is attached to the present specification as an integral part thereof, in which the following has been depicted with an illustrative and non- limiting character, ft should be understood that like reference numbers used in the drawings (if any are used) may identify like components.

FIG. 1 illustrates a prior art pre-coating system and method according to the prior art.

FIG. 2 illustrates a novel pre-coating system and method which may be practiced according to some exemplary, non-limiting embodiments, wherein a lower cut-off point may be employed.

FIG. 3 illustrates a novel pre-coating system and method which may be practiced according to some exemplary, non-limiting embodiments, wherein a lower cut-off point and an upper cut-off point may be employed.

FIG. 4 illustrates sample method steps which may be practiced in whole or in part, according to some exemplary, non-limiting embodiments - for example, using the embodiment shown in FIG.2.

FIG. 5 illustrates sample method steps which may be practiced in whole or in part, according to some exemplary, non-limiting embodiments - for example, using the embodiment shown in FIG. 3.

FIG. 6 schematically depicts at least one cut-off point 110 which may be used with a classification device 109 according to some embodiments. Particles of a slipstream 102b having a size which meets or exceeds the at least one cut-off point 110 may form a coarse stream 102c, and particles of the slipstream 102b having a size which does not meet or exceed the at least one cut-off point 110 may form a fines stream I02d, without limitation. FIG. 7 schematically depicts at least one cut-off point 110 which may be used with a classification device 109 according to some embodiments, e.g., to form a coarse stream 102c for pre-coating filter media of a fitter 108.

FIG. 8 schematically depicts at least one cut-off point 110 which may be used with a classification device 109 according to some embodiments, e.g., to form a refined coarse stream 102f for pre-coating filter media of a filter 108.

FIG. 9 schematically illustrates a filter media pre-coat sequence according to some exemplary, non-limiting embodiments, wherein a coarse stream 102c forms a pre-coat layer on filter media of a filter 108.

FIG. 10 schematically illustrates filtration of a slurry 102, 102b, 102e after pre- coating of filter media, according to some exemplary, non-limiting embodiments.

In the following, the invention will be described in more detail with reference to drawings in conjunction with exemplary embodiments.

DETAILED DESCRIPTION

While the present invention has been described herein using exemplary embodiments of a filtration system 101, and method of operating the same, it should be understood that numerous variations and adaptations will be apparent to those of ordinary skill in the field from tine teachings provided herein.

The detailed embodiments shown and described in the text and figures should not be construed as limiting in scope; rather, all provided embodiments should be considered to be exemplary in nature. Accordingly, this invention is only limited by the appended claims. Hie inventors have recognized a novel and heretofore unappreciated method of performing filtration processes using novel pre-coating techniques and apparatus. An industrial filtration system 1 comprising a "filter" 8, may be altered to accept pre-coat material from slurry to be dewatered by the filter - without necessarily using traditional pre-coat media or employing traditional pre-coating methods or systems.

In other words, the inventors have discovered that a filtration process 101 may, according to some of the embodiments disclosed herein, be advantageously configured to harvest its own pre-coat media, in-situ, directly or indirectly from slurry 102 to be dewatered in the filtration process. This may be done by strategically extracting a coarse solids fraction of particles from the slurry 102 to be dewatered, prior to the slurry 102 entering a filter 108 of the filtration process, and using said coarse solids fraction of particles as a pre-coat material in the filter 108.

It is envisaged that one or more additives {including amounts of traditional pre- coat material) may be combined with the coarse solids fraction of particles from the slurry 102 to be dewatered. However, the inventors believe that pre-coating operations may be most advantageously performed using portions of the slurry 102 to be dewatered.

As an example, an industrial filter 108 (such as an automatic filter press, without limitation), may first receive coarse particles via a coarse stream 102c derived from infeed slurry 102 to be dewatered; the coarse particles effectively serving as insitu harvested pre-coat media. The coarse particles may coat portions of filter media of the filter 108 and form a pre-coat layer thereon (e.g., before each filtration cycle). The filter 108 may then subsequently receive: i.) fine particles via a fines stream 102d, ii.) slurry 102 to be dewatered via a main stream 102a or slurry holding tank 103. or iii.) a combined stream 102e thereof. Turning now to prior art FIG. 1, a conventional filtration system 1 may employ a fitter 8, which is fed slurry 2 to be dewatered and traditional pre-coat media 6, via a pump 7. The pre-coat media 6 is purchased and stored in a pre-coat media holding tank 5, and the slurry 2 is stored in a slurry holding tank 3. A first valve 4a releases slurry 2 to the filter 8, and a second valve 4b releases pre-coat media 6 to the filter.

During a pre-coat cycle, the first valve 4a is closed, and the second valve 4b is opened, to allow pre-coat media 6 to enter the fitter 8 and coat filter media surfaces. At the end of the pre-coat cycle, the second valve is closed, and the first valve 4a is opened to allow slurry 2 to enter the filter 8. in the case of a filter press filter 8, the slurry 2 fills a remaining volume of filter chambers not occupied by the pre-coat media 6. A filtration cycle occurs after the pre-coat cycle, wherein both valves 4a, 4b may be closed during the filtration cycle.

Pre-coat media 6 may be discharged along with cake solids, the cake solids being derived from the slurry 2. Filtrate derived from the slurry 2 may also be removed from the filter 8.

Exemplary, non-limiting systems 101 and methods according to some embodiments are shown and described in FIGS. 2-10.

Turning now to FIG. 2, according to some non-limiting embodiments, a novel pre- coating method and filtration system 101 may involve taking a slipstream 102b or portion of a main feed stream 102a of slurry 102 to be dewatered, and then performing a size separation on the slipstream 102b to form a coarse stream 102c, and a fines stream 102d, without limitation. The size separation may be performed, for example, using a classification device 109 (e.g., a screen, a cyclone, a solid-solid separator, a classifier, a reflux classifier, or the like), without limitation. Optionally, a pump 107b and/or valve 104c may be provided to the filtration system 101 to control flow of the slipstream 102b, relative to a main stream 102a of the infeed siurry 102 to be dewatered. For example, pump 107b and/or valve 104c may be adjusted If more or less pre-coat media is needed in filter 108. In other words, if coarse stream 102c is not enough to provide sufficient pre-coat layers to filter media of the filter 108, then slipstream 102b flow may be increased (e.g., by opening up valve 104c and/or increasing pump 107b throughput) to allow more slurry to classification device 109. At least one cut-off point of the classification device 109 may also be adjusted to increase coarse stream 102c flow to filter 108.

The coarse stream 102c produced from the size separation step may be fed to a filter 108 as part of a filter media p re-coating step. The pre-coating step may comprise a portion of a filtration cycle of the filter 108; or, the pre-coating step may be a separate initialization step which occurs before a filtration cycle of the filter 108 begins, without limitation.

As shown in FIG. 2, the fines stream 102d produced from the size separation step may be recombined with the main feed stream 102a of slurry 102 to form a combined stream 102e, without limitation. However, the fines can be removed (e.g., partially or entirely) from the filtration system 101 or processed by another device (not shown) which is suited for filtering fines. For example, while not shown, the fines stream 102d may be directed to a cyclone, thickener/clarifier, evaporation pond, centrifuge, or a filter which is configured to filter fines, without limitation.

During pre-coating, filter media of the filter 108 may be covered by particles within the coarse stream 102c, forming a pre-coat layer comprised of coarse particles derived from the siurry 102 feeding the filtration process 101. After a sufficient amount of the coarse stream 102c is fed to the filter 108 to adequately pre-coat the filter media and form a pre-coat layer thereon, a second valve 104b may stop the flow of the coarse stream 102c to the filter 1(36, and another first valve 104a may provide the filter 108 with the main feed stream 102a, the fines stream 102d, or a combination stream 102e comprising the main feed stream 102a and the fines stream 102d, without limitation. it should be understood that the first 104a and second 104b valves could be alternatively combined into a three- or four-way valve (e.g., of the T-port or L-port type), without limitation.

Those ordinarily-skilled in the art would appreciate thai many similar changes and adaptations of the flowsheets depicted in FIGS. 2 and 3 can be made without departing from the scope of the inventive concepts disclosed herein. Such alternative embodiments which can be derived from main inventive concepts are anticipated and considered to be obvious in view of this disclosure.

In some embodiments, as suggested in FIG. 3, a second separation step may be employed using a second classification device 109, without limitation, in other words, a plurality of classification devices 109 may be employed - each classification device 109 being provided with its own cut-off point, so as to establish a high end cut-off point and a low cut-off point for a refined coarse stream 102f. The refined coarse stream 102f may be configured for pre-coating filter media of a filter 108, without limitation, and may be substantially comprised of a range of particle sizes (refer to FIG. 8). The range of particle sizes making up the refined coarse stream 102f may preferably lie at or above a filter media aperture size, without limitation.

As shown in FIG. 3 (and suggested in FIGS. 5 and 8), a coarse stream 102c from a first classification device 109a may be subjected to a second separation step in a second classification device 109. An optional holding tank 105 may be provided therebetween. An optional holding tank 105 may be provided downstream of the second classification device 109 as well. A fine solids fraction comprising particles having a size above a cut-off point of the second separation step in the second classification device 109 may be removed from the refined coarse stream 102f, and may make up a large particle stream 102g. The targe particle stream 102g may be returned to slurry holding tank 103, removed from the filtration system 101, or otherwise combined with another slurry stream 102, 102a, I02d, 102e, without limitation. In such an embodiment, particle sizes of a formed pre-coat layer may be more tightly controlled to lie within a specified particle size range, slurry to be dewatered by a filter 108 may be minimally affected (by not removing all coarse particles therefrom to form a pre-coat layer), filtration characteristics of slurry to be dewatered by a filter 108 may be minimally affected (by not significantly changing void spaces between particles for filtrate to pass during a filtration cycle), and filter cake product specifications may be minimally affected from the removal of particles within said specific particle size range of the refined coarse stream 102f and/or pre-coat layer, without limitation.

As shown, embodiments may involve the employment and/or use of certain equipment such as one or more holding/accumulation tanks 103, 105, one or more pumps 107a, 107b, one or more valves 104a, 104b, 104c, and the like, without limitation. Moreover, while not expressly shown, instrumentation (e.g., a number of online sensors which are configured to independently measure different attributes of a filtration process throughout a filtration system 101) may be employed. The data gathered by the instrumentation may control the one or more pumps 107a, 107b, the one or more valves 104a, 104b, 104c, flows to and/or from the one or more holding/accumulation tanks 103, 105, or the like, autonomously, via an operating algorithm and control system, without limitation. it should be understood that a desired cake product may have certain target specifications. For example, a target cake moisture and/or a target cake density may be specified as a target specification for a particular process. Since target specifications may change over time - especially with dynamic filtration processes, pre-coating steps may be varied oyer time to maintain cake products which meet or exceed target specifications, without limitation.

According to some embodiments, one, some, or all portions of a filtration system 101 may be controlled via a local or remote control system using a computing device configured with software and an algorithm which is configured to control certain system features (e.g., configured to control one or more valves 104a-c, pumps 107a-b, filtration parameters, set points for controlling filter 108, cut-off point(s) of classification device 109 parameters, etc.) independently, or in concert.

At least one cut-off point may be associated with a separation step occurring via the classification device 109; the at least one cut-off point helping to determine and establish where material in the slipstream 102b goes. The at least one cutoff point between the coarse stream 102c and the fines stream 1Q2d leaving the classification device 109 may be fixed or adjustable, but it is preferably set to work synergistically with the type of filter media used with the filter 108 as well as the infeed slurry 102 composition. The at least one cut-off point is preferably set in a manner which discourages blinding of filter media by fine particles within slurry to be dewatered.

The at least one cut-off point may be set using any number of factors, such as mass and/or st2e (e.g., mass median diameter (MMD)) of particles in slurry to be dewatered. In some non-limiting embodiments, density (e.g., actual particle density p _P ) of particles in slurry to be dewatered may be used as a factor in determining at feast one cut-off point. In some embodiments, mean particle size distribution (PSD) of particles in slurry to be dewatered may be used in determining at least one cut-off threshold, without limitation. In some

embodiments, a % passing curve may be used in determining at least one cut-off threshold, without limitation. In some embodiments, particle shapes or shape distributions of particles in slurry to be dewatered may be used in determining at least one cut-off threshold, without limitation. The at least one cut-off point may provide a hard (i.e., very tight/narrow) cut-off window, range, or set point; or, it may comprise a softer (i.e., very loose/flexible) cut-off window, range, or set point having more lenient tolerances with regard to the amount of fines from slipstream 102b which are permitted in the coarse stream 102c.

The at least one cut-off point may be set such mat the coarse stream 102c might not necessarily meet or exceed optimal design criteria or ideal filter media pre- coat materia! specifications; however, is important that the coarse stream 102c at least adequately performs its function as a useful pre-coat layer material for filter media provided to the filter 108. in some instances, the at least one cut-off point may comprise a PSD "D-value" of D10, D50, or D90, for a particular stream 102c, 102d, without limitation. In some instances, a P50 or P80 confidence level may be associated with at least one cut-off point, or to a particular stream 102c, 102d, without limitation.

For example, a classification device 109 may be purposefully designed to have at least one cut-off point which is best suited for a particular filtration system 108, filtration process, or characteristic's) thereof. The at least one cut-off point could be set during, before, or after the design or fabrication of a retrofit kit for an existing filtration system 1; or, it could be set during, before, or after the commissioning of a new filtration system 101 , without limitation. in some embodiments, the classification device 109 may be provided with means for adjusting at least one cut-off point as a control variable or operational set point. In such embodiments, a control system may automatically adjust the at least one cut-off point to accommodate for changes within the filtration process of a system 101 in real time, or periodically, to accommodate infrequent fi!tration process changes (e.g., which may occur upon filter media replacement, a change in filter media type, or a modification to the filtration process or system 101), without limitation. An operator may manually adjust the set point using a control interface of a control system as well, by providing an input to the control interface, without limitation. Means for manually- and or mechanically- adjusting the set point of the classification device 109 are also envisaged.

St is preferred to select at feast one cut-off point which advantageously compliments at least one physical characteristic of the filter media, such as filter media aperture size, filter media porosity, filter media material, filter media size, and/or filter media dimenslon(s) (e.g., thickness, width, length, area), without limitation. in some embodiments, it may be preferable to design the at least one cut-off point of the classification device 109, such that it advantageously compliments any one or more of the following: the material composition of slurry being filtered in the system 101; the real-time mean particle size distribution (PSD) of the infeed slurry 102 to be filtered; the real-time mean (PSD) of a fines stream 102d, main stream 102a, or combination stream 102e entering the filter 108; the realtime mean (PSD) of slipstream 102b entering the classification device 109; the particular filtration process or operation being employed, the particular operational set points or process control variables being used within the filtration system 101, the type of filter 108 being provided to the system 101 , a desired throughput or operational capacity of the filter 108 (e.g., the amount of cake or filtrate produced or desired to be produced per unit of time), a desired filtration cake product target specification, a desired pre-coat thickness, a desired cycle time, or the like, without limitation.

To increase the efficacy of the coarse stream 102c as a satisfactory pre-coat media, it Is preferred that the at least one cut-off point for the classification device 109 be set such that a bulk majority of the particles within coarse stream 102c are equal to or larger than a filter media aperture, in order to prevent excessive blinding of the filter media associated with the filter 108. It is also preferred that particles in coarse stream 102c and making up pre-coat layers are equal to or larger than filter media apertures to prevent excessive buildup of fines within the fitter media apertures. Where used herein the term "aperture" may comprise one or more "openings" or "pores," without (imitation and may represent a sample average, without limitation.

As a non-limiting example, in some non-limiting embodiments, if using a filter media comprising a 70 micron aperture for a filter 108, the at least one cut-off point of the classification device 109 may be set such that most of the particles in the coarse stream 102c are at least 70 microns in size, without limitation. in some instances, fine adjustments of at least one cut-off point may be required to effectively capture fines of a stream 102a, 102d, 102e within a pre-coat layer formed using the coarse stream 102c. For example, PSD online measurements may determine that a large quantity of fine particles within a stream 102a, 102d, 102e to be dewatered by a filter 108 comprise a first diameter (e.g., 40 micron particles). The first diameter might be smaller man a second diameter; the second diameter pertaining to an average size of apertures of filter media (e.g., 50 micron openings or pores in filter media, without limitation}. Should a cut-off point be set at a third diameter (e.g., 60 microns), and the pre-coat layers formed by the coarse stream 102c are not effective at capturing fines therein during a filtration cyde(s), then said cut-off point may be adjusted up or down to a fourth diameter (e.g., reduced to 55 microns), without limitation, it should be made dear that actual sizes of first, second, third, and/or fourth diameters are not limiting, and may, in practice, vary from the aforementioned example sizes.

The classification device 109 may automatically determine, adjust, and/or tailor the cut point between the coarse 102c and fine I02d streams over the coarse of a single filtration cycle and/or intermittently - over the coarse of a number of filtration cycles, without limitation. For example, according to some

embodiments, a cut point of the classification device 109 may be changed after every "ΛΓ filtration cycles, or after every "ΛΓ hours, without limitation. EXAMPLE

In some embodiments, when a filter cycle commences, a filter feed pump 107 might begin by pumping a coarse stream 102c of slurry from a holding tank 105 tank to a filter 108. An algorithm may be used to calculate how much of the coarse stream 102c might be required to create an adequate pre-coat layer (e.g.. using particles in the coarse stream 102c), of a chosen thickness, onto a filter media surface. Without stopping the pump 107 and/or reducing pressure, an automated valve 104a on a slurry holding tank 103 may open once the desired pre-coat layer thickness has been achieved; wherein a valve I04b controlling flow from the holding tank 105 of the coarse stream 102c would close. The filter 108 may then continue to be filled with slurry from a main stream 102a, combined stream 102e, and/or fines stream 102d until the filtration cycle is completed.

In some embodiments, a layer of coarse particles from a coarse stream 102c and/or refined coarse stream 102f may be applied to a filter media surface, and the coarse particles therein may be consolidated into a pre-coat layer on the filter media as suggested in FIG. 9. The pre-coat layer might serve as sacrificial filtration media configured to contain/bap fine particulates in slurry 102, 102a, 102d, I02e, 102g to be dewatered by the filter 108 (see FIG. 10).

By modifying a particle size cut-point of one or more classification devices 109, such as one or more hydrocyclones, a filter media having an optimal aperture size for the coarse tailings stream may be selected for use in a filtration process/system 101 , and/or a coarse stream 102c may be optimized to best capture fines once it is consolidated as a pre-coat layer on the filter media, without limitation. The slurry 102 used in the process may, in some embodiments, comprise minerals processing tailings, concentrate, sludge, slurry, waste, or other material to be dewatered, without limitation.

Where used herein, the terms "filter," "filtering machine," "filtering device ^* 'filtration apparatus,. and/or the like, may be used interchangeably and, according to some embodiments, may comprise a pressure filter or vacuum fitter, without limitation. These terms may include, without limitation, disc filters, drum filters, pan filters, horizontal belt fitters, stacked filter press (e.g., Pneumapress®, Outotec® Larox PF pressure filter) and/or the like. However, the inventors deem the disclosed inventive aspects to be particularly advantageous for use with filter presses (e.g., horizontal automatic filter presses), without limitation.

Where a single element is disclosed in this specification, or illustrated in the appended drawings, it should be understood to mean that one or more of said elements may be provided or substituted in its place. For example, where used herein, the term "filter* may, according to some embodiments, comprise "at least one ^* filter, "one or more ^* filters, a "network" of filters, and/or a "plurality" of filters, without limitation. As another example, where used herein, the term "pump ^* may, according to some embodiments, comprise "at least one" pump, "one or more" pumps, a "network" of pumps, and/or a "plurality" of pumps, without limitation. As yet another example, where used herein, the term "valve" may, according to some embodiments, comprise "at least one" valve, "one or more ^* valves, a "network ^* of valves, and/or a "plurality ^* of valves, without limitation. As yet a further example, where used herein, the term "classification device" may, according to some embodiments, comprise "at least one" classification device, "one or more ^* classification devices, a "network" of classification devices, and/or a "plurality" of classification devices, without limitation. The same as above may apply to other elements or components disclosed herein, including, but not limited to "holding tank", "stream", "feed", and the like, wherein said terms may he referencing a singular feature or a plurality of features, without limitation.

It should also be understood, that any combination of disclosed elements may form a unique embodiment of the invention. For example, a retrofit kit embodiment may be established by combining in any permutation, the necessary piping (i.e., for streams 102b, 102c, 102d), classification device(s) 109, pump(s) 107b, and/or valve(s) 104c - to implement a functionally similar or equivalent filtration system 101 , method, or flowsheet as the one depicted in FIG. 1.

The disclosure of every patent, patent application, and publication cited, listed, named, or mentioned herein is hereby incorporated by reference in its entirety, for any and all purposes, as If fully set forth herein.

While this subject matter has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations can be devised by others skilled in the art without departing from the true spirit and scope of the subject matter described herein. The appended claims may include some, but not all of such embodiments and equivalent variations.

The described embodiments are to be considered in ail respects only as illustrative and not restrictive. The scope of the invention is. therefore, indicated and governed only by the appended claims, rather than by the foregoing description. Ail embodiments which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

For example, as shown in FIGS. 2 and 3, according to some non-limiting exemplary embodiments, an optional auxiliary holding tank 111 may be employed to a filtration system 101 to take up slack in the system/process - in particular, if/when the quality of incoming slurry 102 is too poor to filter when course solids are removed therefrom to form pre-coat media for filter 108. It is envisaged that there may be Instances where filter 108 may be unable to efficiently filter slurry from a particular stream 102a, 102e, 102d, 102g, and In this case, it may be temporarily inadvisable to extract a slipstream 102b from a main stream 102a of incoming slurry 102 to produce a course stream 102c, 102f for pre-coatjng filter 108. Such instances of poor slurry 102 quality may include, for instance, occasions where incoming feed slurry 102 is comprised of too many fines and not enough coarse solids to effectively practice the inventive pre-coat concepts disclosed herein.

The contents of the holding tank 111 may contain traditional/conventional pre- coat media described herein. Alternatively, the contents of the holding tank 111 may serve as storage means for excess course solids from a course stream 102c, 102f or over-produced course fractions built up in the filtration system 101 over time. Alternatively, the contents of the holding tank 111 may comprise refined tailings which have been pre- processed, refined, categorized (e.g., screened, separated, etc.), and/or cleaned for suitable use as pre-coat media. Alternatively, the contents of the holding tank 111 may comprise any combination of: traditional pre-coat media, one or more additives, excess course solids from a course stream 102c, 102f, and/or said refined tailings, without limitation.

In this regard, if a control system of the filtration system 101 deems that incoming slurry 102 is of such poor composition that a coarse stream 102c, 102f cannot be adequately extracted therefrom, or, that a slipstream 102b cannot be adequately taken therefrom, without causing problematic filterability issues (e.g., compromising filter cake quality or increasing required filtration cycle time needed for filter 108), the control system can, in response to such determination, cause valve 104c and/or pump 107b to be temporarily shut or stopped, respectively, and can further cause valve 104d to be temporarily opened, so that pre-coatirtg operations can still be performed with filter 108 using the material provided to and/or stored in the auxiliary holding tank 111, without limitation. Conversely, upon a contro! system of the filtration system 101 determining that the infeed slurry 102 qualify has improved or is sufficient for removing a slipstream 102b therefrom to provide a course stream 102c, 102f (via classification/separation step(s)) _> the control system may cause the valve 104d to the auxiliary holding tank 111 to be temporarily dosed, and further cause valve 104c and/or pump 107b to be temporarily opened or re-started, respectively, to resume norma! pre-coating operations.

Though the optional auxiliary holding tank 111 and associated valve 104d is shown to feed a holding tank 105, it may alternatively be positioned to directly feed filter 108 just upstream from pump 107, without limitation.

In some further embodiments, it is envisaged that a locally-sourced dry material (e.g., dewatered tailings, overburden material, or the like, without limitation) can be can screened and/or sized, and provided to auxiliary holding tank 111, in order to provide a quality source of back-up pre-coat material for the filter 108. The dry material preferably meets or exceeds a required specification for pre- coat media, thereby obviating the need to bring in traditional/conventional consumable pre-coat products which might need to be separately-purchased, commercially. The required specification for the dry materia! should preferably be complementary to the filtration system 101 or its process, and be configured such that it does not significantly affect or disrupt filtration operations when used as a pre-coat media for filter 108. For example, the required specification may, in some instances, include a mean panicle size distribution which closely matches an existing set cut-off point 110 for coarse stream 102c, 102f. Atlernatively, the required specification may include a range of particle sizes which largely lie between two existing preset cut-off points 110, without limitation.

A contractor or other entity may provide, fabricate, install, maintain, operate, or offer for sale a filtration system 101 as disclosed herein. A contractor or other entity may provide, fabricate, install, maintain, operate, or offer for sale one or more adaptations to an existing filter 8 or filtration system 1 , in order to effectively provide a filtration system 101 substantially as described herein. A contractor or other entity may provide, fabricate, install, maintain, operate, or offer for sale one or more components or elements of a filtration system 101 disclosed herein - including, but not limited to, means for connecting said one or more components or elements (e.g., piping, tubing, connectors, joints, and the like).

A contractor or other entity might practice any one or more of the method steps described herein. In any combination or order, without limitation. A contractor or other entity might operate a filter 108 or filtration system 101 in whole, or in part, as shown and described - in order to enjoy certain benefits associated with the disclosed inventive concepts.

A contractor or other entity may receive a bid request for a project related to designing, fabricating, delivering, installing, operating, or performing maintenance on a filter 108 or filtration system 101, or a component thereof as substantially described herein; for example, with the intention or purpose of converting an existing filter 8 or filtration operation 1 to a filtration system 101 as substantially described herein. Or, a contractor or other entity may offer to design such a system, device, or apparatus, or provide a process, service, or perform one or more method steps pertaining thereto, for a client. A contractor or other entity may offer to retrofit or may actually retrofit an existing filter 8 or filtration system 1 with any one or more of the components or elements described herein.

The contractor or other entity may provide, for example, any one or more of the inventive devices or features thereof shown and/or described in the embodiments discussed above in any combination, permutation, or fashion. The contractor or other entity may provide such devices or features by selling those devices or features; or, by offering to sell those devices or features. The contractor or other entity may provide various embodiments that are sized, shaped, specked, and/or otherwise configured to meet the design criteria of a particular client or customer or end user of a filtration system or filter thereof.

The contractor or other entity may subcontract or facilitate the fabrication, delivery, sale, and/or installation of any components) or subcomponents of the system and apparatus disclosed, or, may subcontract or facilitate the provision of any devices or components thereof which might be used to reproduce one or more inventive aspects of the embodiments disclosed.

The contractor or other entity may also maintain, modify, or upgrade a filtration system based on teachings herein. The contractor or other entity may provide maintenance or modifications by subcontracting services or by directly providing those services or components needed for maintenance, modifications, retrofit, or upgrades; and, in some cases, the contractor or other entity may modify an existing filter or filtration system by virtue of provision of a retrofit kit to arrive at a modified filter or filtration system comprising one or more of the described elements, design features, components, devices, method steps, or inventive concepts discussed herein.

Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention.

REFERENCE NUMERAL IDENTIFIERS

1. Fiftration system (prior art)

2. Infeecf stream of slurry (e.g. , substance to be dewatered)

3. Slurry holding tank

4a. First valve (e.g., control valve)

4b. Second valve (e.g. , control valve)

5. Pre-coat media holding tank

6. Pre-coat media (e.g., Diatomaceous earth, periite, sand, etc.)

7. Pump

8. Filter

101. Fiftration system

102. Infeed stream of slurry (e.g., substance to be dewatered) 102a. Main feed stream of slurry

102b. Slipstream of slurry

102c. Coarse stream

102d. Fines stream

102e. Combination of main feed 102a slurry 102 and fines 102d

102f. Refined coarse stream

102g. Large particle stream

103. Slurry holding tank

104a. First valve (e.g., control valve)

104b. Second valve (e.g., control valve)

104c. Third valve (e.g., control valve) (optional)

104d. Third valve (e.g., control valve) (optional)

105. Holding tank (e.g., coarse solids fraction of slurry)

107a. First pump

107b. Second pump (optional)

108. Filter (e.g ., horizontal filter press, drum filter 109. Classification device (e.g., one or more screens, cyclones, solid- solid separation devices, classifiers (e.g., reflux classifiers), and/or the like, without limitation)

110. Cut-off point (e.g., set point value, minimum particle size threshold, maximum particle size threshold, preferably greater than or equal to filter media apertures or pores)

111. Auxiliary Holding tank(s) (optional)

ABSTRACT OF THE DISCLOSURE

A method for pre-coating filter media of a filter (108) may comprise the step of performing a separation on a first portion of slurry (102) to be dewatered by the fitter (108). A coarse stream (102c) may be produced from the separation and at least a portion of the coarse stream (102c) may be provided to the filter (108) to pre-coat the fitter media of the filter (108). The coarse stream (102c) or a refined coarse stream (I02f) may be provided to the filter (108) before providing a second portion of the slurry (102) to the filter (108). Filtration systems (101) and methods may allow pre-coating techniques without necessarily using a consumable pre-coat media (e.g., diatomaceous earth).