# US 10,441,958 B2 · System, method and apparatus for froth flotation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,441,958 B2 - Document ID: US10441958B2 - Status: Granted - Kind: B2 - Application number: 15/755,680 - Filed: 2016-08-29 - Published: 2018-08-30 - Granted: 2019-10-15 - Earliest claimed: 2015-08-28 - Assignees: Hunter Process Technologies Pty Limited - Applicants: Hunter Process Technologies Pty Limited - Inventors: Graeme J. Jameson - Web page: https://patentgrep.com/patent/US10441958B2 ## CPC - B03D 1/247: {Mixing gas and slurry in a device separate from the flotation tank, i.e. reactor-separator type} - B03D 1/028: {Control and monitoring of flotation processes; computer models therefor} - B03D 1/08: Subsequent treatment of concentrated product (froth dispersion B01D19/02) - B03D 1/1475: {Flotation tanks having means for discharging the pulp, e.g. as a bleed stream} - B03D 2203/08: Coal ores, fly ash or soot - B03D: FLOTATION; DIFFERENTIAL SEDIMENTATION (sedimentation in general B01D21/00; in combination with other separation of solids B03B; sink-float separation B03B5/28; detergents, soaps C11D) ## Abstract A separation system is disclosed for separating selected particles from a mixture of particles in a fluid. The system includes a froth flotation vessel 10 into which in use the mixture of particles and fluid are subjected to an upward flow of an introduced gas to form a froth layer 13 which rises above an interface 14 formed between the froth layer 13 and the mixture of particles and fluid 12, such that a quantity of the selected particles is conveyed out of the vessel 10 by the froth layer 13 to become a first product of the system. The vessel 10 also has a first outlet 29 arranged in use for receiving a flow of some of the mixture of particles and fluid from the vessel 10, an entry to the first outlet 29 being located in a region proximate to, but below, the interface 14. The vessel also has a second outlet 20 arranged in use for receiving a flow of some of the mixture of particles and fluid from a region of the vessel 10 which is located below the first outlet 29. In use the first outlet 29 receives a quantity of the selected particles which were not conveyed out of the vessel by the froth layer 13, and the second outlet 20 receives a quantity of the selected particles in a first by-product of the system. The first by-product comprises a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet 29. The flow of the mixture of particles and fluid from the vessel 10 via the first outlet 29 passes to a classification device 31, 76 which separates the flow into two or more fractions on the basis of their size or density or a combination of the two. ## Claims ### Claim 1 A separation system for separating selected particles from a mixture of particles in a fluid, the system comprising: a froth flotation vessel into which in use the mixture of particles and fluid are subjected to an upward flow of an introduced gas so that a bed of said particles becomes hydraulically supported by the fluid in the vessel in a fluidised bed region thereof, and so that a froth layer is formed which rises above an interface formed between the froth layer and the mixture of particles and fluid, such that a quantity of the selected particles is conveyed out of the vessel by the froth layer to become a first product concentrate of the system; a first outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from the vessel, an entry to the first outlet being located in a region proximate to, but below, the interface; and a second outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from the fluidised bed region of the vessel which is located below the first outlet; wherein in use: the first outlet receives a quantity of the selected particles which were not conveyed out of the vessel by the froth layer in a flow which passes to a classification apparatus to produce a flow of relatively coarser and/or higher density particles which includes an amount of the selected particles as a second product concentrate of the separation system, and a separate flow of relatively finer and/or lower density particles an amount of which is directed to return via an entry port into the vessel, to form part of the fluidised bed of particles in the fluidised bed region, and the second outlet receives a quantity of the selected particles in a first by-product of the system, the first by-product comprises a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet. ### Claim 2 (depends on 1) A separation system as claimed in claim 1, wherein the classification apparatus which produces a flow of relatively coarser particles and a separate flow of relatively finer particles is one or more of the group comprising: a screen, a sieve bend, a vibrating screen deck, and a vibratory screen. ### Claim 3 (depends on 1) A separation system as claimed in claim 1, wherein the classification apparatus which produces a flow of relatively higher density particles, and a separate flow of relatively lower density particles is one or more of the group comprising: a hydrocyclone, a spiral, a gravity table, a teeter bed and a reflux classifier. ### Claim 4 (depends on 1) A separation system as claimed in claim 1, wherein a control system controls the amount of the said flow of relatively finer particles and/or relatively lower density particles which is directed to return to the vessel, or to be removed as a second by-product of the separation system. ### Claim 5 (depends on 4) A separation system as claimed in claim 4, wherein the control system further includes a sensor which senses the position of the interface in the froth flotation vessel in relation to the first outlet. ### Claim 6 (depends on 4) A separation system as claimed in claim 4, wherein fresh feed of selected particles in a mixture of particles in a fluid is introduced in-line into the flow of relatively finer particles and/or relatively lower density particles which is directed to the vessel. ### Claim 7 (depends on 6) A separation system as claimed in claim 6, wherein gas for froth flotation separation is introduced in-line into the flow which is directed to the vessel. ### Claim 8 (depends on 1) A separation system as claimed in claim 1, wherein the flow which is directed to return to the froth flotation vessel as a recycle from the classification apparatus, creates the hydraulic support for the fluidised bed of particles in the fluid in the froth flotation vessel. ### Claim 9 (depends on 1) A separation system as claimed in claim 1, wherein the froth flotation vessel operates in two zones, a lowermost region of higher particle concentration, and an uppermost region of lower particle concentration. ### Claim 10 (depends on 9) A separation system as claimed in claim 9, wherein fresh feed of selected particles in a mixture of particles in a fluid combined with a flow gas which is introduced via an entry port in the lowermost region forms part of the fluidised bed of particles suspended in liquid, through which bubbles of gas flow upwardly toward the uppermost region. ### Claim 11 (depends on 1) A separation system as claimed in claim 1, wherein a chamber located within the froth flotation vessel forms a part of the first outlet, the chamber having an entry which is oriented away from the upward flow of introduced gas in the vessel, in use arranged so that said upward flow of gas is separated from the flow of particles and fluid which is received into the first outlet. ### Claim 12 (depends on 1) A separation system as claimed in claim 1, wherein an uppermost region of the froth flotation vessel is configured to have a region of lower cross-sectional area compared to the remainder of the froth flotation vessel, thereby crowding the rising froth so as to increase the superficial velocity of the selected particles out of the froth flotation vessel. ### Claim 13 A separation system for separating selected particles from a mixture of particles in a fluid, the system comprising: a froth flotation vessel into which in use the mixture of particles and fluid are subjected to an upward flow of an introduced gas to form a froth layer which rises above an interface formed between the froth layer and the mixture of particles and fluid, such that a quantity of the selected particles is conveyed out of the vessel by the froth layer to become a first product concentrate of the system; and a first outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from the vessel including a quantity of the selected particles which were not conveyed out of the vessel by the froth layer, an entry to the first outlet being located in a region below the interface; wherein the mixture of particles and fluid received in the first outlet passes to a classification apparatus which in use produces: a first flow being of relatively coarser and/or higher density particles, which includes a concentrated amount of the selected particles, as a second product concentrate of the system; and a second flow being of relatively finer particles and/or relatively lower density particles, which is either returned to the vessel, or becomes a by-product of the separation system, the selected particles mainly being delivered into the first flow compared to the second flow. ### Claim 14 (depends on 13) A separation system as claimed in claim 13, further comprising a second outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from a region of the vessel which is located below the first outlet, said flow forming a further by-product of the system which comprises a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet. ### Claim 15 (depends on 13) A separation system as claimed in claim 13, wherein the classification apparatus is one or more of the group comprising: a screen, a sieve bend, a vibrating screen deck, a vibratory screen, a hydrocyclone, a spiral, a gravity table, a teeter bed and a reflux classifier. ### Claim 16 (depends on 13) A separation system as claimed in claim 13, wherein a control system directs an amount of the second flow either to return to the vessel, or to become a by-product of the separation system. ### Claim 17 (depends on 13) A separation system as claimed in claim 13, wherein the control system further includes a sensor which senses the position of the interface in the froth flotation vessel in relation to the first outlet. ### Claim 18 (depends on 13) A separation system as claimed in any claim 13, wherein fresh feed of selected particles in a mixture of particles in a fluid is introduced in-line into the flow of relatively finer particles and/or relatively lower density particles which is directed to the vessel. ### Claim 19 (depends on 18) A separation system as claimed in claim 18, wherein gas for froth flotation separation is introduced in-line into the flow which is directed to the vessel. ### Claim 20 (depends on 13) A separation system as claimed in claim 13, wherein the flow which is directed to return to the froth flotation vessel as a recycle from the classification apparatus, creates a fluidised bed of particles which are hydraulically supported in the fluid in the froth flotation vessel. ### Claim 21 (depends on 20) A separation system as claimed in claim 20, wherein fresh feed of selected particles in a mixture of particles in a fluid combined with a flow gas which is introduced via an entry port in the lowermost region form part of the fluidised bed of particles suspended in liquid, through which bubbles of gas flow upwardly toward the uppermost region. ### Claim 22 (depends on 13) A separation system as claimed in claim 13, wherein the froth flotation vessel operates in two zones, a lowermost region of higher particle concentration, and an uppermost region of lower particle concentration. ### Claim 23 A separation system for separating selected particles from a mixture of particles in a fluid, the system comprising: a froth flotation vessel into which in use the mixture of particles and fluid are subjected to an upward flow of an introduced gas so that a bed of said particles becomes hydraulically supported by the fluid in the vessel in a fluidised bed region thereof, and so that a froth layer is formed which rises above an interface formed between the froth layer and the mixture of particles and fluid, such that a quantity of the selected particles is conveyed out of the vessel by the froth layer; a first outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from the vessel including a quantity of the selected particles which were not conveyed out of the vessel by the froth layer, an entry to the first outlet being located in a region below the interface; a second outlet arranged in use for receiving a flow of some of the mixture of particles and fluid from the fluidised bed region of the vessel, the second outlet being located below the first outlet, the flow comprising a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet; wherein in use the froth flotation vessel has a control system for controlling at least one of: the flow of the mixture of particles and fluid passing through the first outlet, so as to maintain the position of the interface in the froth flotation vessel in relation to the first outlet; and the flow of the mixture of particles and fluid passing through the second outlet by use of a valve that is actuated by a sensing device which measures a physical parameter of the flow through the second outlet and which produces a signal to control the valve, so as to maintain the physical parameter at a stipulated value at that depth of the fluidised bed. ### Claim 24 (depends on 23) A separation system as claimed in claim 23, wherein the flow of particles and fluid in the first outlet passes to a classification apparatus to produce a flow of relatively coarser and/or higher density particles and a separate flow of relatively finer and or lower density particles, and the control system is arranged to control one of the said flows from the classification apparatus. ### Claim 25 (depends on 24) A separation system as claimed in claim 24, wherein the control system controls the amount of the said flow of relatively finer particles and/or relatively lower density particles which is directed either to return to the vessel, or to become a second by-product of the separation system. ### Claim 26 (depends on 25) A separation system as claimed in claim 25, wherein fresh feed of selected particles in a mixture of particles in a fluid is introduced in-line into the flow of relatively finer particles and/or relatively lower density particles which is directed to the vessel. ### Claim 27 (depends on 26) A separation system as claimed in claim 26, wherein gas for froth flotation separation is introduced in-line into the flow which is directed to the vessel. ### Claim 28 (depends on 25) A separation system as claimed in claim 25, wherein fresh feed of selected particles in a mixture of particles in a fluid combined with a flow gas is introduced into, and forms part of, the fluidised bed of particles suspended in liquid, through which bubbles of gas flow upwardly toward the interface. ### Claim 29 A separation system as claimed in 24, wherein the classification apparatus is one or more of the group comprising: a screen, a sieve bend, a vibrating screen deck, a vibratory screen, a hydrocyclone, a spiral, a gravity table, a teeter bed and a reflux classifier. ### Claim 30 (depends on 23) A separation system as claimed in claim 23, wherein the control system further includes a sensor which senses the position of the interface in the froth flotation vessel in relation to the first outlet. ### Claim 31 (depends on 23) A separation system as claimed in claim 23, wherein the physical parameter includes one or more of the group comprising: the percentage of particulates in the fluid, the density of the particulates, and the mass flowrate of the particulates in the mixture of particulates in fluid. ### Claim 32 (depends on 23) A separation system as claimed in claim 23, wherein the flow of the mixture of particles and fluid passing through the second outlet forms a first by-product of the separation system, the froth layer becomes a first product concentrate of the system, and the flow of a relatively coarser and/or higher density particles from the classification apparatus includes a concentrated amount of the selected particles, and becomes a second product concentrate of the system. ### Claim 33 A method of separation of selected particles from a mixture of particles in a fluid, the method comprising the steps of: subjecting the mixture of particles and fluid to an upward flow of an introduced gas in a froth flotation vessel, to form a froth layer which rises above an interface formed between the froth layer and the mixture of particles and fluid, such that a quantity of the selected particles is conveyed out of the vessel by the froth layer to become a first product concentrate of the system; removing a flow of some of the mixture of particles and fluid from the vessel via a first outlet which is arranged with an entry in a region below the interface, the said flow including a quantity of the selected particles which were not conveyed out of the vessel by the froth layer; classifying the flow of particles in fluid removed via the first outlet using a classification apparatus to produce (i) a flow of relatively coarser and/or a flow of relatively higher density particles, including an amount of the selected particles, as a second product concentrate of the separation system, and (ii) a separate flow of relatively finer and/or relatively lower density particles, an amount of which is directed to return to the vessel; and removing a flow of some of the mixture of particles and fluid from the vessel via a second outlet which is located in a region of the vessel which is below the first outlet, the said flow including a quantity of the selected particles in a first by-product of the system which comprises a relatively higher percentage of solids compared to the flow of particles and fluid in the first outlet. ### Claim 34 (depends on 33) A method as claimed in claim 33, further including the step of controlling the amount of the said flow of particles and fluid from the vessel via the second outlet so as to maintain a physical parameter of the flow through the second outlet. ### Claim 35 (depends on 33) A method as claimed in claim 33, further comprising the step of controlling the amount of the said flow of relatively finer particles and/or relatively lower density particles which is directed to return to the vessel, so as to maintain the position of the froth interface at a level where the entry to the first outlet is below the interface. ### Claim 36 (depends on 35) A method as claimed in claim 35, further comprising the step of introducing a fresh feed of selected particles in a mixture of particles in a fluid into the flow of relatively finer particles and/or relatively lower density particles which is directed to the vessel. ### Claim 37 (depends on 35) A method as claimed in claim 35, further comprising the step of introducing a gas for froth flotation separation into the flow which is directed to the vessel.