WO2021058802A1 - Traitement de boue - Google Patents

Traitement de boue Download PDF

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Publication number
WO2021058802A1
WO2021058802A1 PCT/EP2020/077006 EP2020077006W WO2021058802A1 WO 2021058802 A1 WO2021058802 A1 WO 2021058802A1 EP 2020077006 W EP2020077006 W EP 2020077006W WO 2021058802 A1 WO2021058802 A1 WO 2021058802A1
Authority
WO
WIPO (PCT)
Prior art keywords
sensor
slurry
treatment vessel
accordance
arrangement
Prior art date
Application number
PCT/EP2020/077006
Other languages
English (en)
Inventor
Paul Davies
Original Assignee
Metso Sweden Ab
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 Metso Sweden Ab filed Critical Metso Sweden Ab
Publication of WO2021058802A1 publication Critical patent/WO2021058802A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/32—Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/30—Control equipment
    • B01D21/34—Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D3/00—Differential sedimentation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5209—Regulation methods for flocculation or precipitation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/04—Investigating sedimentation of particle suspensions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N15/075—Investigating concentration of particle suspensions by optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N2015/0687—Investigating concentration of particle suspensions in solutions, e.g. non volatile residue

Definitions

  • the present invention relates to the determination of properties of a slurry, for example within the mining industry.
  • Thickeners When extracting minerals or other valuable materials from the earth, resource consumption, such as power and water, is coming more and more into focus.
  • Thickeners sometimes also called clarifiers, depending on the application, can be used to recover immediately reusable process water, as well as to extract fines and other materials.
  • Thickeners are applied in e.g. the mineral and aggregate industry but also in wastewater management. The advantages vary between different applications. For example, thickeners can be used in locations where water is in short supply such that reusable process water can be fed back to the plant. They can also be used to reduce the size of, or if combined with filtration of the underflow of the thickener, possibly eliminate, tailings dams and to remove minerals and fines from water.
  • additives comprising chemicals such as coagulants and/or flocculants are used.
  • turbidity sensors which intermittently measures the settling rate of particles suspended in the liquid. Based on the information provided by the turbidity sensor, the feed rate of the additives can be adjusted to maintain optimal settling properties.
  • the invention is based on the realization that the previously used solution of adjusting an additive feed rate based on the output from a turbidity sensor has certain drawbacks. For example, it is known that flocculation is best performed within a certain range of feed solids content measured for example as percentage by weight. However, it is often the case that in a slurry transported to a thickener the feed solids content will vary over time and it has also been determined that the optimal range will vary with different solids, e.g. varying particle size distribution; varying particle material, etc.
  • An object of the invention is to overcome, or at least lessen the above-mentioned problems, especially those related to feeding of thickeners.
  • a particular object is to provide an arrangement for determining at least one property of a slurry comprising solids suspended in liquid.
  • an arrangement comprising a treatment vessel having a predefined volume; a first sensor arranged at or near the treatment vessel and arranged to determine a settling rate of solids of the slurry when contained in the treatment vessel; a second sensor arranged at or near the treatment vessel and arranged to determine a density of the slurry contained in the treatment vessel and wherein an output from the second sensor can be used to determine the percent solids in the slurry.
  • Being able to monitor the settling rate and the percent solids in the slurry makes it possible to continuously obtain relevant detailed information about the slurry.
  • arranging both sensors at or near the treatment vessel creates a compact solution with all necessary equipment conveniently located.
  • the arrangement further comprises a control unit arranged to receive signals from at least the second sensor, wherein the control unit is arranged to determine the percent solids in the slurry based on the output from the second sensor.
  • the percent solids in the slurry By determining the density of the content in the treatment vessel, i.e. the slurry, it is possible to determine the percent solids in the slurry. This can be achieved by knowing the density of the liquid phase of the slurry, usually water, and assuming that the density of the solids is the same for all particles. Thereafter the percent solids in the slurry can easily be calculated. To have continuous updates about the percent solids in the slurry makes it easier to decide feed rate of the additive.
  • control unit is arranged to receive signals from at least the first and second sensor and the control unit is arranged to adjust a feed rate of an additive to the slurry based on the output from the first sensor. This allows for continuous adaptation of the additive feed rate.
  • control unit is arranged to adjust a feed rate of additional liquid that may be added to the slurry based on information from the second sensor.
  • Additional liquid also called dilution liquid
  • dilution liquid can be added to the slurry to reduce the solids content in the slurry. This may for example be beneficial to increase the performance of the additive, such as flocculants.
  • the feed rate of additional liquid that may be added to the slurry is based on information from the first and the second sensor. This is an especially convenient solution since it allows both the settling rate and the percent solids to influence the dilution water.
  • the additive comprises a chemical such as a coagulant or a flocculant.
  • control unit is arranged to adjust the feed rate of additional liquid that may be added to the slurry based on information from at least one of the first and the second sensor as well as information about a feed rate of the additive.
  • it may be predicted that optimal flocculation will occur within a certain range of percent solids.
  • it may be the case that flocculation is taking place according to plan.
  • the flocculant pump is running at a very high rate or even at or near its maximum, which would indicate that flocculation is indeed not performed as intended.
  • the control unit can be arranged to increase or decrease the amount of dilution water fed to the slurry such that a new, more correct range of percent solids can be determined. Without monitoring the actual feed rate of the additive, in addition to the information provided by the first and second sensors, this could go on undetected for a long time.
  • the second sensor comprises at least one load cell arranged to determine the weight of the slurry contained in the treatment vessel.
  • a load cell is simple and reliable solution. Since the weight of the treatment vessel as such as well as any auxiliary equipment attached to the treatment vessel is known and since the volume of the treatment vessel is known, the output from the load cell can easily be used to determine the density of the slurry in the treatment vessel. This could be done by for example a lookup table by means of which the density of the slurry can be determined.
  • the first sensor comprises a turbidity sensor.
  • Turbidity sensors or turbidity probes are well known in the art and provide reliable function for determining settling rate of particles.
  • the arrangement further comprises a third sensor arranged upstream the treatment vessel and the first and the second sensor, wherein the third sensor is arranged to determine a density of the slurry upstream of the treatment vessel and wherein an output from this third sensor can be used to determine the percent solids in the slurry.
  • the additional liquid is added to the slurry downstream of the third sensor and upstream of the second sensor.
  • This has the advantage that it is possible to determine the percent solids of both the diluted and the undiluted slurry.
  • the information provided by the sensors arranged downstream of the addition of dilution liquid i.e. the first and second sensors and possibly also the information from the additive pump, it is possible to fine tune the addition of dilution liquid.
  • the third sensor is arranged at or near a second treatment vessel having a predefined volume. Similar to how the first and second sensors are arranged, the third sensor is arranged at or near a treatment vessel having a predefined volume which can be filled with slurry such that the density thereof can be determined and thus the percent solids in the undiluted slurry.
  • a method for determining at least one property of a slurry comprising solids suspended in liquid comprising the steps of providing a treatment vessel having a predefined volume; determining a settling rate of solids of the slurry contained in the treatment vessel by means of a first sensor arranged at or near the treatment vessel; determining a density of the slurry contained in the treatment vessel by means of a second sensor arranged at or near the treatment vessel; determining the percent solids in the slurry using an output from said second sensor.
  • the steps of the method need not be performed in the order they are mentioned above.
  • the determination of the settling rate can be done independently of the determination of the percent solids.
  • the method further comprises the step of determining the percent solids in the slurry based on the output from the second sensor by means of a control unit which is arranged to receive signals from at least said second sensor.
  • control unit is arranged to receive signals from at least the first and second sensors and wherein the method further comprises the step of adjusting a feed rate of an additive to the slurry based on the output from the first sensor by means of the control unit.
  • the method further comprises the step of adjusting a feed rate of additional liquid that may be added to the slurry based on information from the second sensor by means of the control unit.
  • the method further comprises the step of adjusting the feed rate of additional liquid that may be added to the slurry based on information from the first and the second sensor.
  • the additive comprises a chemical such as a coagulant or a flocculant.
  • the method further comprises the step of adjusting the feed rate of additional liquid that may be added to the slurry based on information from at least one of the first and the second sensor as well as information about the feed rate of the additive.
  • the method further comprises the step of providing a third sensor upstream of the treatment vessel and the first and the second sensor and determining a density of the slurry upstream of the treatment vessel and wherein an output from the third sensor can be used to determine the percent solids in the slurry.
  • the method further comprises the step of arranging the third sensor at or near a second treatment vessel.
  • Fig. 1 shows a schematic structure of the arrangement in accordance with a first embodiment of the invention.
  • Fig. 2 shows a first embodiment of a treatment equipment in accordance with the invention.
  • Fig. 3 shows a second embodiment of a treatment equipment in accordance with the invention.
  • the arrangement 100 may start with a feed flow F intended to enter a thickener 20.
  • the feed flow F typically comprises a slurry coming from a previous step in for example a mineral processing facility.
  • the thickener is arranged to separate water via the overflow 21 and recover e.g. fines from the slurry at the underflow 22. The water can then be reused in the mineral processing or be otherwise taken care of in subsequent treatment steps.
  • the underflow will typically be transported towards for example a tailings dam or further treated to recover valuable material therefrom.
  • chemicals are often added to the slurry, such as flocculants which are intended to floe solid particles to each other in order to increase their settling rate.
  • Flocculants may for example comprise non-ionic, anionic or cationic flocculants. Such flocculant may in this embodiment added to the slurry at an earlier stage and be present in the feed flow F.
  • a first treatment vessel 1 and a second treatment vessel 2 are arranged such that they may extract samples at different locations along the feed towards the thickener or from the thickener.
  • a dilution flow DF arranged to let water from the overflow of the thickener flow back into the feed flow F when and if so is required.
  • a first slurry sample may be pumped, or otherwise transported, into the treatment vessel 2 through sample intake 3 from the feed flow F.
  • the treatment vessel has a defined volume and may be arranged with an overflow or similar such that the treatment vessel 2 is always filed with the exact same volume of slurry.
  • a pinch valve 4 is activated and closes the flow of slurry towards the treatment vessel 2.
  • a vacuum relief valve 5 is also arranged at or near the pinch valve 4 and a vacuum relief valve 5, which, when activated, will drain the pipe system 3 leading to the treatment vessel 2.
  • a load cell 6 which is arranged to measure the weight of the treatment vessel 2.
  • the load cell 6 may of course be located anywhere suitable.
  • the treatment vessel 2 may be arranged to hang from the load cell 6.
  • the exact location thereof is less relevant. Since the weight of all equipment, treatment vessel 2 and any auxiliary equipment, is known and since the volume of the treatment vessel is known, it is easy to deduct the exact weight of the slurry sample located within the treatment vessel. And since the density of water is known and if it is assumed that the solid particles of the slurry all have the same density, the weight percentage of solids TS in the slurry can easily be calculated from a simple weight measurement of the sample.
  • the treatment vessel 1 has the exact same configuration except that it further comprises a clarometer in the form of a turbidity sensor 7 which is arranged to determine the settling rate SR of the particles in the treatment vessel 1.
  • the settling rate is an indicator as to if the amount of flocculant is correct and is therefore often monitored.
  • the integration of both clarometer 7 and load cell 6 into the same treatment vessel provides a compact solution in one unit.
  • the equipment also includes a control unit 7 arranged in communication with the other parts of the equipment.
  • the treatment vessel 1 is located downstream of the entrance of any dilution water DF whereas treatment vessel 2 is arranged upstream of the entrance of DF. This allows for continuous monitoring of undiluted slurry as well as diluted slurry and as will be described below, this has several advantages.
  • One way of running the arrangement of the invention is to determine a setpoint for the total solids content TS in the diluted slurry and a setpoint for the settling rate SR.
  • the control unit will run the pump for dilution water based on information regarding the total solid content TS from treatment vessels 1 , 2 only where the output from the sensor of treatment vessel 2 can be used to provide information about the total solid content TS of the undiluted slurry which is then used to determine the amount of dilution liquid necessary and the output from the sensor of treatment vessel 1 may be used to provide feedback as to the total solid content TS in the diluted slurry.
  • the flocculant pump will be run based on information regarding the settling rate SR in treatment vessel 1 only.
  • the measurements of total solid content TS and the settling rate SR are done with the intention of maintaining their individual setpoints.
  • Flowever it is also possible to operate the system in a more integrated manner where the input from all sensors are taken into consideration. It is often is assumed that a certain range of total solids content TS should be optimal for the flocculation to occur. Flowever, sometimes this assumption turns out to be wrong. It may be the case that the information from the load cell and the clarometer shows that flocculation is taking place according to plan at the intended total solids content TS, indicating that the assumption of optimal total solids content TS is correct.
  • the flocculant pump is running at or near its maximum, which would indicate that flocculation is indeed not performed as intended.
  • the control unit can be arranged to increase or decrease the amount of dilution water fed to the slurry such that a new, more correct range of percent solids TS can be determined. It is thus possible to effectively search for a new, more correct range of optimal solids content TS by means of the arrangement in accordance with the invention. It is also possible to add historical data to be used as a pre-warning system for process deviation. Without monitoring the actual feed rate of the additive, in addition to the information provided by the sensors measuring settling rate and total solids content, this could go on undetected for a long time.
  • the skilled person realizes that a number of modifications of the embodiments described herein are possible without departing from the scope of the invention, which is defined in the appended claims.
  • the arrangement may not necessarily be using load cells in order to determine the density of the slurry.
  • Other solutions such as nuclear density sensors may be applied.
  • the important thing is that the density of the slurry can be obtained.
  • clarometer, turbidity sensor, turbidity probe are used herein. They all aim to determine the settling rate of the particles in the treatment vessel and other equipment capable of this may be applied.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Dispersion Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

L'invention concerne un agencement permettant de déterminer au moins une propriété d'une suspension comprenant des solides en suspension dans un liquide, l'agencement comprenant une cuve de traitement ayant un volume prédéfini, un premier capteur disposé au niveau ou à proximité de la cuve de traitement et agencé pour déterminer un taux de sédimentation de solides de ladite suspension lorsqu'il est contenu dans la cuve de traitement et un second capteur disposé au niveau ou à proximité de la cuve de traitement et agencé pour déterminer la densité de la suspension contenue dans la cuve de traitement. Une sortie dudit second capteur peut être utilisée pour déterminer le pourcentage de solides dans la suspension.
PCT/EP2020/077006 2019-09-25 2020-09-25 Traitement de boue WO2021058802A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1951082A SE544240C2 (en) 2019-09-25 2019-09-25 Slurry treatment with adjusted feed rate of additional liquid
SE1951082-5 2019-09-25

Publications (1)

Publication Number Publication Date
WO2021058802A1 true WO2021058802A1 (fr) 2021-04-01

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ID=72665263

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2020/077006 WO2021058802A1 (fr) 2019-09-25 2020-09-25 Traitement de boue

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CN (2) CN112546684A (fr)
SE (1) SE544240C2 (fr)
WO (1) WO2021058802A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2973311A1 (fr) * 2016-03-29 2016-05-30 Imperial Oil Resources Limited Methode de mesure d'un apport de boue pour un procede de separation solide-liquide
WO2018132309A1 (fr) * 2017-01-10 2018-07-19 Vermeer Manufacturing Company Systèmes et procédés de dosage de boues de terre avec un additif pour modifier une propriété fluide de la boue
WO2018137893A1 (fr) * 2017-01-30 2018-08-02 Intellisense.Io Ltd Commande de récupération de minéraux

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5910312A (ja) * 1982-07-08 1984-01-19 Toshiba Corp 汚泥濃縮槽の汚泥投入制御方法
JP2004167401A (ja) * 2002-11-20 2004-06-17 Toshiba Corp 排水処理装置および排水処理方法
US11130686B2 (en) * 2017-01-10 2021-09-28 Vermeer Manufacturing Company Systems and methods for dosing slurries to remove suspended solids
CN108553952B (zh) * 2018-04-13 2021-04-06 北京科技大学 底流浓度自适应调控的膏体浓密机及精准监测与调控方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2973311A1 (fr) * 2016-03-29 2016-05-30 Imperial Oil Resources Limited Methode de mesure d'un apport de boue pour un procede de separation solide-liquide
WO2018132309A1 (fr) * 2017-01-10 2018-07-19 Vermeer Manufacturing Company Systèmes et procédés de dosage de boues de terre avec un additif pour modifier une propriété fluide de la boue
WO2018137893A1 (fr) * 2017-01-30 2018-08-02 Intellisense.Io Ltd Commande de récupération de minéraux

Also Published As

Publication number Publication date
SE1951082A1 (en) 2021-03-26
CN212941642U (zh) 2021-04-13
SE544240C2 (en) 2022-03-15
CN112546684A (zh) 2021-03-26

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