WO2019145910A1 - Système et procédé pour le pré-enrobage d'un filtre - Google Patents

Système et procédé pour le pré-enrobage d'un filtre Download PDF

Info

Publication number
WO2019145910A1
WO2019145910A1 PCT/IB2019/050638 IB2019050638W WO2019145910A1 WO 2019145910 A1 WO2019145910 A1 WO 2019145910A1 IB 2019050638 W IB2019050638 W IB 2019050638W WO 2019145910 A1 WO2019145910 A1 WO 2019145910A1
Authority
WO
WIPO (PCT)
Prior art keywords
filter
stream
slurry
coarse
media
Prior art date
Application number
PCT/IB2019/050638
Other languages
English (en)
Inventor
James CHAPONNEL
Original Assignee
Flsmidth A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Flsmidth A/S filed Critical Flsmidth A/S
Publication of WO2019145910A1 publication Critical patent/WO2019145910A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D37/00—Processes of filtration
    • B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D36/00—Filter circuits or combinations of filters with other separating devices
    • B01D36/04—Combinations of filters with settling tanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D36/00—Filter circuits or combinations of filters with other separating devices
    • B01D36/04—Combinations of filters with settling tanks
    • B01D36/045—Combination of filters with centrifugal separation devices

Definitions

  • 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).
  • 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).
  • 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.
  • 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.
  • 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.
  • filtrate passes through the pre-coat layer, the filter media, and then the drum, and is removed from the drum filter.
  • 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.
  • material for pre-coatings i.e., pre-coat media
  • pre-coat media must be purchased as a consumable.
  • 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 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the first portion of the slurry (102) may comprise a slipstream (102b), without limitation.
  • 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.
  • the separation may comprise a size separation performed using a classification device (109).
  • 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.
  • 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.
  • 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.
  • 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.
  • the first portion of the slurry (102) may comprise a slipstream (102b).
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • valves (104a, 104b) may be closed at the same time.
  • 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.
  • only one of the valves (104a, 104b) may be open at a particular time during pre- coating and filtration.
  • 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.
  • 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).
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 least 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).
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • one or more additives may be combined with the coarse solids fraction of particles from the slurry 102 to be dewatered.
  • pre-coating operations may be most advantageously performed using portions of the slurry 102 to be dewatered.
  • an industrial filter 108 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.
  • 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.
  • 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.
  • 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.
  • FIGS. 2-10 Exemplary, non-limiting systems 101 and methods according to some embodiments are shown and described in FIGS. 2-10.
  • 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.
  • 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.
  • pump 107b and/or valve 104c may be adjusted If more or less pre-coat media is needed in filter 108.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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)
  • 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.
  • 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.
  • 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
  • instrumentation 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.
  • a desired cake product may have certain target specifications.
  • 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.
  • 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.
  • 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.
  • mass and/or st2e e.g., mass median diameter (MMD)
  • density e.g., actual particle density p P
  • 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.
  • a % passing curve may be used in determining at least one cut-off threshold, without limitation.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 least 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.
  • filter media aperture size e.g., filter media porosity, filter media material, filter media size, and/or filter media dimenslon(s) (e.g., thickness, width, length, area), without limitation.
  • the at least one cut-off point of the classification device 109 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 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.
  • aperture may comprise one or more "openings" or "pores,” without (imitation and may represent a sample average, without limitation.
  • 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.
  • 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 ⁇ .
  • 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
  • a cut point of the classification device 109 may be changed after every " ⁇ filtration cycles, or after every " ⁇ hours, without limitation.
  • 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.
  • 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.
  • 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).
  • 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.
  • filter 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.
  • stacked filter press e.g., Pneumapress®, Outotec® Larox PF pressure filter
  • the inventors deem the disclosed inventive aspects to be particularly advantageous for use with filter presses (e.g., horizontal automatic filter presses), without limitation.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • valve 104c and/or pump 107b can 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.
  • 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.
  • 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.
  • a locally-sourced dry material e.g., dewatered tailings, overburden material, or the like, without limitation
  • a locally-sourced dry material 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 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. Atgruatively, 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.
  • 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.
  • First valve e.g., control valve
  • Second valve e.g. , control valve
  • Pre-coat media e.g., Diatomaceous earth, periite, sand, etc.
  • First valve e.g., control valve
  • Second valve e.g., control valve
  • Third valve e.g., control valve
  • Third valve e.g., control valve
  • Holding tank e.g., coarse solids fraction of slurry
  • 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)
  • 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
  • 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).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtration Of Liquid (AREA)

Abstract

Un procédé de pré-enrobage de milieux filtrants d'un filtre (108) peut comprendre l'étape consistant à effectuer une séparation sur une première partie de suspension (102) à déshydrater par le filtre (108). Un flux grossier (102c) peut être produit à partir de la séparation et au moins une partie du flux grossier (102c) peut être fournie au filtre (108) pour pré-enrober le milieu filtrant du filtre (108). Le flux grossier (102c) ou un flux grossier raffiné (102f) peut être fourni au filtre (108) avant de fournir une seconde partie de la suspension (102) au filtre (108). Des systèmes de filtration (101) et des procédés peuvent permettre des techniques de pré-enrobage sans nécessairement utiliser un milieu de pré-enrobage consommable (par exemple, une terre de diatomées).
PCT/IB2019/050638 2018-01-25 2019-01-25 Système et procédé pour le pré-enrobage d'un filtre WO2019145910A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201862621729P 2018-01-25 2018-01-25
US62/621,729 2018-01-25

Publications (1)

Publication Number Publication Date
WO2019145910A1 true WO2019145910A1 (fr) 2019-08-01

Family

ID=65278427

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2019/050638 WO2019145910A1 (fr) 2018-01-25 2019-01-25 Système et procédé pour le pré-enrobage d'un filtre

Country Status (1)

Country Link
WO (1) WO2019145910A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003076045A1 (fr) * 2002-03-08 2003-09-18 Drm, Dr. Müller Ag Procede de filtration continu d'une saumure brute destinee a etre utilisee dans l'electrolyse chlore-alcali
EP2184096A1 (fr) * 2007-08-30 2010-05-12 Kyushu University, National University Corporation Filtre et procédé de filtration
WO2010052130A2 (fr) * 2008-11-07 2010-05-14 Basf Se Procédé de séparation de particules d'agent auxiliaire de filtration pour la filtration à précouche

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003076045A1 (fr) * 2002-03-08 2003-09-18 Drm, Dr. Müller Ag Procede de filtration continu d'une saumure brute destinee a etre utilisee dans l'electrolyse chlore-alcali
EP2184096A1 (fr) * 2007-08-30 2010-05-12 Kyushu University, National University Corporation Filtre et procédé de filtration
WO2010052130A2 (fr) * 2008-11-07 2010-05-14 Basf Se Procédé de séparation de particules d'agent auxiliaire de filtration pour la filtration à précouche

Similar Documents

Publication Publication Date Title
CA2970745C (fr) Appareil de tamis inter etage rotatif
US20130213903A1 (en) Screening methods and apparatus
JPH0242951B2 (fr)
CN102921532B (zh) 一种用于硅藻土矿的层流离心选矿方法
CN116221603B (zh) 一种干燥机滴油回收处理装置及其控制系统
WO2019145910A1 (fr) Système et procédé pour le pré-enrobage d'un filtre
NL2009216C2 (en) Internally fed drum filter for treating waste water comprising an inlet distribution arrangement.
KR20060021848A (ko) 액체에서 입자를 연속 여과하는 방법 및 장치
JP4553815B2 (ja) スクリュー式濾過脱水装置
JP5334155B2 (ja) 処理液循環利用システム
CN209465126U (zh) 一种球磨机过滤装置
US2330542A (en) Dewatering of suspended solids
CN104941900A (zh) 一种除杂筛
CN111076499A (zh) 一种应用于高盐废水资源化结晶盐的干燥系统
JP2016198734A (ja) 分離濾過システムおよび分離濾過方法
CN205570790U (zh) 一种自动上料分级吹风扬扬机
CA3005217A1 (fr) Pretraitement de residus fins de sables bitumineux par retrait des debris
US20090272504A1 (en) Method and apparatus for the integrated cleaning of a paper-pulp processing plant
RU2699608C1 (ru) Керамический дисковый вакуумный фильтр и способ фильтрования суспензий
CN108187394B (zh) 固液分离机过滤段筛网高度调整装置及其调整方法
EP4129439A1 (fr) Dispositif de filtration et ligne de distribution pour la distribution d'un fluide a particules solides en suspension
CN211099537U (zh) 一种湿混凝土分离机的出料斗及湿混凝土分离机
CN218879686U (zh) 一种细砂回收机
CN1607297A (zh) 筛网
CN214391123U (zh) 一种粉末涂料用高效率筛分装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19703197

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19703197

Country of ref document: EP

Kind code of ref document: A1