WO2023211463A1 - Systèmes et procédés d'élimination de microparticules d'un fluide de travail de métaux - Google Patents

Systèmes et procédés d'élimination de microparticules d'un fluide de travail de métaux Download PDF

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Publication number
WO2023211463A1
WO2023211463A1 PCT/US2022/026970 US2022026970W WO2023211463A1 WO 2023211463 A1 WO2023211463 A1 WO 2023211463A1 US 2022026970 W US2022026970 W US 2022026970W WO 2023211463 A1 WO2023211463 A1 WO 2023211463A1
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Prior art keywords
metalworking fluid
fluid
contaminated
metal particles
metalworking
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PCT/US2022/026970
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English (en)
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John Michael Burke
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John Michael Burke
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Priority to PCT/US2022/026970 priority Critical patent/WO2023211463A1/fr
Publication of WO2023211463A1 publication Critical patent/WO2023211463A1/fr

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    • 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
    • C02F1/24—Treatment of water, waste water, or sewage by flotation
    • 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
    • B03D1/00—Flotation
    • B03D1/02—Froth-flotation processes
    • B03D1/028—Control and monitoring of flotation processes; computer models therefor
    • 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
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1431—Dissolved air flotation machines
    • 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
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1443—Feed or discharge mechanisms for flotation tanks
    • B03D1/1456—Feed mechanisms for the slurry
    • 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
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/1443—Feed or discharge mechanisms for flotation tanks
    • B03D1/1462—Discharge mechanisms for the froth
    • 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
    • B03D1/00—Flotation
    • B03D1/14—Flotation machines
    • B03D1/24—Pneumatic
    • B03D1/247—Mixing gas and slurry in a device separate from the flotation tank, i.e. reactor-separator type
    • 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
    • B03D3/06—Flocculation
    • 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
    • B03D2203/00—Specified materials treated by the flotation agents; specified applications
    • B03D2203/008—Water purification, e.g. for process water recycling
    • 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
    • C02F1/34—Treatment of water, waste water, or sewage with mechanical oscillations
    • 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
    • C02F1/38—Treatment of water, waste water, or sewage by centrifugal separation
    • 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
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/32—Hydrocarbons, e.g. oil
    • C02F2101/325—Emulsions
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/02—Fluid flow conditions
    • C02F2301/022—Laminar
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/046—Recirculation with an external loop
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/26—Reducing the size of particles, liquid droplets or bubbles, e.g. by crushing, grinding, spraying, creation of microbubbles or nanobubbles

Definitions

  • the present invention generally relates to methods and systems for removal of metal particle from a metalworking fluid, and in particular to methods and systems for removal of metal microparticles from a metalworking fluid comprising an anionic and/or nonionic emulsifier.
  • micro-fines metal forming or metal deformation processes create very small metal particles referred to as micro-fines. These particles are typically from 30 micron to sub-micron (below one micron) in size.
  • the metalworking fluid is an emulsion (in particular, an oil-in-water emulsion)
  • these submicron non-ferrous metal particles cannot be removed by conventional filtration and separation techniques such as pressure media filtration, vacuum assist media filtration, settling separation and centrifugation because these methods will remove the emulsion along with micro-fines associated with the fluid from the deformation process. Since the non-ferrous sub-micron particles have low magnetic permeability, they cannot be removed by magnetic separators.
  • One remedy is to perform a partial release of the emulsion lubricant , thus diluting the metallic particle loading as expressed in milligrams per liter (mg/L), or a complete recharge of the emulsion lubricant, commonly referred to as a DCR, dump clean and recharge.
  • a DCR is a waste of product and a potential stress on the environment.
  • these micro-fine particles carry a positive charge when they are immediately stripped away from the base metal.
  • metallic copper parts have an effective zero valence expressed as Cu°.
  • these micro-fine particles are stripped away from the base part, they are driven to a free ion form and carry two positive charges and expressed as Cu ++ .
  • aluminum is stripped from its base part in a deformation process as referenced above, the result is aluminum converting from Al° to Al +++ .
  • These metals in their ionic form will readily react with any anion in solution and form an electro-kinetic bond. [See Fig. 1], The higher the anionic charge, the more micro-fine particles will adhere to that anion.
  • the Cu ++ or Al +++ bond form a precipitate or more chemically accurate a metallic soap.
  • the copper and aluminum soaps carry the micro particles and lubricant to the die surfaces as well as the entire metalworking machine surface.
  • the metallic soap residues will interfere with the machine functions as well as accelerate die wear as previously mentioned.
  • chelating chemicals such as a sodium salt of ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid (NTA).
  • EDTA ethylenediaminetetraacetic acid
  • NTA nitrilotriacetic acid
  • a method of removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles including pressurizing a first clean metalworking fluid with gas to provide an aerated metalworking fluid; releasing the pressure of the aerated metalworking fluid to form a plurality of bubbles; applying a shear force to the contaminated metalworking fluid to separate the emulsion droplets from the metal particles; flowing the contaminated metalworking fluid with the aerated metalworking fluid in a laminar flow to form a combined fluid, wherein the flowing occurs during the formation of the plurality of bubbles and while the emulsion droplets are separated from the metal particles, and wherein the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles; releasing the combined fluid into a flotation tank; and removing the metal particles to form a second clean metalworking fluid.
  • the contacting occurs within about 0.5 second or less after the releasing of the pressure of the aerated metalworking fluid. In some embodiments the flowing occurs within about 0.5 second or less after applying the shear force.
  • the shear force is a hydraulic shear force, for example applying a hydraulic shear force including injecting the aerated metalworking fluid into a flow of contaminated metal working fluid in a direction perpendicular to the flow of contaminated metal working fluid. In other embodiments the shear force is a mechanically generated shear force.
  • the amount of emulsifier in the second clean metalworking fluid may be within about 0.1 v% to about 15 v% of the amount of emulsifier in the contaminated metalworking fluid.
  • the coagulation channel may be substantially straight.
  • a method for removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles, the method comprising: pressurizing the contaminated metalworking fluid with gas in a pressurization vessel to provide an aerated metalworking fluid; flowing the aerated metalworking fluid from the bottom of the pressurization vessel to a coagulation channel; applying a shear force to the aerated metalworking fluid to separate the emulsion droplets from the metal particles; reducing the pressure of the aerated metalworking fluid to provide a plurality of bubbles, wherein the reducing the pressure occurs after applying the shear force and while the emulsion droplets are separated from the metal particles; flowing the aerated metalworking fluid in a laminar flow through the coagulation channel to a floatation tank, wherein the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles; releasing the aerated metalworking fluid into the flotation tank; and
  • the reducing the pressure is about 0.5 second or less after applying the shear force. In some embodiments the reducing the pressure occurs within 0.5 second after applying the shear force.
  • the shear force may be a mechanically generated shear force.
  • the amount of emulsifier in the clean metalworking fluid may be within about 0.1 v% to about 15 v% of the amount of emulsifier in the contaminated metalworking fluid.
  • the coagulation channel may be substantially straight.
  • the time sufficient for the plurality of bubbles to attach to the metal particles is at least about 1.0 second.
  • the metal particles have an average particle size of about 30 micron or less.
  • the first clean metalworking fluid or clean metalworking fluid is pressurized with gas at about 3.5 bar to about 6.2 bar for about two minutes or longer.
  • the aerated metalworking fluid and the contaminated metalworking fluid are flowed in a flow ratio in a range of 1 :5 (v:v) to 1 : 1 (v:v).
  • the metal particles are non-ferrous, for example, the metal particles may comprise one or more of copper, aluminum, nickel, lead, titanium, tungsten and molybdenum.
  • the gas comprises atmospheric air.
  • the gas is selected from nitrogen, oxygen, ozone, and combinations thereof.
  • the gas bubbles may have a size in a range of from about 10 microns to about 50 microns.
  • the contaminated metalworking fluid comprises an emulsifier.
  • emulsifier may be an anionic emulsifier, a nonionic emulsifier, a combination of anionic and nonionic emulsifier, or a cationic emulsifier.
  • the nonionic emulsifier is present at about 0.1% wt. to 20% wt of the anionic emulsifier.
  • the contaminated metalworking fluid may be an oil-in-water phase emulsion.
  • the emulsifier (or emulsion droplets) may have a size in a range of about 10 microns to 1 micron.
  • the metalworking process may be a metal forming or metal removal process.
  • a system for removing particles from a contaminated metalworking fluid may include a pressurization tank; a mechanical shear device; a coagulation channel having a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second; and a flotation tank.
  • the coagulation channel may be substantially straight.
  • a system for removing particles from a contaminated metalworking fluid may include a pressurization tank; a hydraulic shear device; a coagulation channel having a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second; and a flotation tank.
  • the coagulation channel may be substantially straight.
  • the hydraulic shear device includes an inner pipe; an outer pipe surrounding the inner pipe and approximately coaxial with the inner pipe; a first end cap and a second end cap, each sized to seal an end of the inner pipe; and a rod having a first end and a second end and extending through the inner pipe and the through the first end cap, the second end of the rod being connected to the second end cap.
  • the rod may be capable of pushing the end cap off of the second end of the inner pipe to release a first fluid flowing through the inner pipe in a direction perpendicular to a flow of a second fluid through the outer pipe.
  • the rod may be capable of pulling the end cap on the second end of the inner pipe to seal the flow of fluid out of the inner pipe through the second end.
  • the hydraulic shear device includes a pipe and a nozzle for injecting a fluid perpendicular to the direction of the pipe.
  • Fig. l is a drawing of a typical emulsified oil-in-water metalworking fluid comprising a water phase and oil droplets surrounded or substantially surrounded by emulsifier molecules;
  • Fig. 2 is a drawing of a typical contaminated metalworking fluid including positively charged metal particles;
  • Fig. 3 is a drawing of flocculated positively charged metal particles and negatively charged emulsion droplets
  • Fig. 4 is a drawing of slightly negatively charged air bubbles associated with flocculated metal particle and emulsion droplets
  • Fig. 5 is a drawing of emulsion droplets separated from metal particles after application of shear force to a contaminated metalworking fluid
  • FIG. 6A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention
  • Fig. 6B a side view identical to 6A wherein the system components are numerically labeled;
  • Fig. 7A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention.
  • Fig. 7B is a side view identical to 7A wherein the system components are numerically labeled;
  • Fig. 7C is a cut-away view of the hydraulic shear device of the system for removing particles from a contaminated metalworking fluid shown in Figs. 7A-7B;
  • Fig. 7D is a cut-away view identical to Fig. 7C wherein the system components are numerically labeled;
  • FIG. 8 A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention
  • Fig. 8B is a side view identical to 8A wherein the system components are numerically labeled;
  • Fig. 9A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention.
  • Fig. 9B is a side view identical to Fig. 9A wherein the system components are numerically labeled;
  • FIG. 10A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention
  • Fig. 10B is a side view identical to Fig. 10A wherein the system components are numerically labeled;
  • Fig. 11 A is a side view of a system for removing particles from a contaminated metalworking fluid in accordance with an exemplary embodiment of the present invention.
  • Fig. 1 IB is a side view identical to Fig. 11 A wherein the system components are numerically labeled.
  • Various embodiments are described which provide systems and methods of removing metal particles from a metalworking fluid, in particular for removing metal particles having an average size of about 30 microns or less from a metalworking fluid comprising an emulsion, such as an oil- in-water emulsion comprising an anionic and/or nonionic emulsifier.
  • an emulsion such as an oil- in-water emulsion comprising an anionic and/or nonionic emulsifier.
  • the methods and systems of the present invention provide several advantages over the prior art.
  • the present invention is capable of removing particles (e.g., metal particles) having an size or average size of about 30 microns to about 10 microns or even smaller from solution.
  • the present invention is capable of removing such particles without substantially affecting the emulsion composition, that is without removing emulsifier droplets from the metalworking fluid.
  • the bond e.g., electro-kinetic bond
  • the particle e.g., metal ion
  • the emulsifier e.g., anionic chemical
  • the inventors have discovered that preferential separation can be achieved through application of a shear force to the emulsion-particle flocculant, contacting the fluid comprising the separated emulsion droplets and particles with a fluid comprising a dissolved gas for a time sufficient for gas bubbles to form and attach to the particles, and maintaining the contact of the fluids in a laminar or quiescent flow to avoid the emulsion droplets displacing the gas bubbles and recombining with the particles.
  • Prior art teaches a gentle application of contaminated metalworking solution; shearing the contaminated metalworking fluid is opposite of common practice.
  • metal particles from the metalworking fluid allows for an improved stability of the metalworking fluid emulsion by allowing the emulsifiers to better react as anions and not a metal-anion complex, which forms when metal particles contaminate the metalworking fluid.
  • a nonionic surfactant along with anionic surfactants at a ratio of about 0.1% wt. to 20% wt. (nonionic / anionic) as the total weight of the emulsifier package is anticipated to improve the efficiency of the micro particle separation (also used along with high shear force enhancement).
  • Various embodiments are described which provide methods of removing metal particles from a metalworking fluid.
  • the removal process typically uses dissolved air flotation (DAF) plus shear forces followed by laminar flow fluid alignment and quiescent flotation to separate metal particles from the emulsion droplets.
  • DAF dissolved air flotation
  • the metalworking fluid may be a fluid used in any metalworking process, such as a metal deformation process.
  • Metal removal deformation includes but is not limited to one or more of the following operations: machining deformation, impact deformation, pressure deformation, and extrusion deformation.
  • Machining deformation processes include, but are not limited to: drilling, boring, reaming, tapping, thread rolling, thread chasing, hobbing, milling, turning, sawing, planning, scraping, shearing, shaving, broaching, cutting, grinding, polishing, burnishing, and vibratory deburring.
  • Impact deformation processes include, but are not limited to: stamping, cold forging, warm forging, and hot forging.
  • Pressure deformation processes include, but are not limited to: hydroforming, sintering, hot rolling, and cold rolling.
  • Extrusion deformation processes include, but are not limited to: wire and rod forming through a die or series of dies, bar to rod rolling, rod to strip rolling, rod to wire drawing (intermediate wire), and rod to wire drawing (fine wire).
  • Such metalworking processes can result in metal particles contaminating the metalworking fluid.
  • Methods of the present invention can be used to remove metal particles contaminating a metalworking fluid after a metalworking process.
  • Such metal particles may have an average particle size of about 50 micron or less, about 40 micron or less, about 30 micron or less, about 20 micron or less, or about 10 micron or less.
  • such metal particles may have an average particle size of about 1 micron to about 50 microns, about 1 micron to about 40 microns, about 1 micron to about 30 microns, about 1 micron to about 25 microns, about 1 micron to about 20 microns, about 1 micron to about 10 microns, about 0.1 micron to about 10 micron, about 0.1 micron to about 20 micron, about 0.1 micron to about 30 micron.
  • the metal worked (e.g., deformed) and accordingly, the metal particle contaminants typically comprise non-ferrous metals or non-ferrous alloys, that is, the predominant alloy is not iron.
  • the metal worked (e.g., deformed) and accordingly, the metal particle contaminants comprise or consist essentially of copper, aluminum, nickel, lead, titanium, tungsten, intermetallics such as molybdenum, or a combination thereof.
  • such metalworking fluid comprises an emulsifier, forming an emulsion.
  • the emulsion is an oil-in-water emulsion, although a water-in-oil emulsion is also contemplated.
  • the emulsion may comprise anionic surfactants, dispersants and/or emulsifiers used individually or in combination.
  • the emulsion may comprise nonionic surfactants, dispersants and/or emulsifiers used individually or in combination.
  • the emulsion may comprise a combination of anionic and nonionic surfactants, dispersants, and/or emulsifiers used individually or in combination.
  • the emulsion comprises a nonionic emulsifier and an anionic emulsifier, wherein the nonionic emulsifier is present at about 0.1 wt% to about 20 wt%, about 0.5 wt% to about 15 wt%, about 1 wt% to about 10 wt%, about 10 wt% to about 20 wt%, or about 0.1 to about 5 wt% of the anionic emulsifier.
  • the metalworking fluid may be based on a cationic surfactant, dispersant, and/or emulsifier.
  • Anionic emulsifiers include, but are not limited to, fatty carboxylic acids; and phosphated, mixed blend of C12-C14 and C12-C15 ethoxylated alcohols.
  • Nonlimiting examples of suitable anionic emulsifiers include sodium dodecylbenzene sulfonate, sodium dodecyl sulphate (SDS), sodium stearate, N-ethoxy sulfonate, alcohol propoxy sulphate (APS), alpha-olefin sulfonate (AOS), alkyl polyalkoxy alkyl sulfonate, alkyl aryl polyalkoxy alkyl sulfonate, branched alkyl benzene sulfonate, docusate sodium, guerbet alkoxy sulphate, sulfonated, ethoxylated alcohol or alkyl phenol, and alkyl alcohol propoxylated sulphate.
  • SDS sodium dodecyl sulphate
  • APS alcohol propoxy sulphate
  • AOS alpha-olefin sulfonate
  • the emulsifier is a nonionic emulsifier.
  • Nonionic emulsifiers include, but are not limited to, fatty alcohol ethoxylates, castor-oil based ethoxylates, fatty acid ethoxylates, ethylene oxi de-propylene oxide (EO-PO) block copolymers (poloxamers), sorbitan(ol) ester ethoxylates, lanolin alcohol ethoxylates, polyol esters, and lanolin alcohols.
  • Nonlimiting examples of nonionic emulsifiers include polyhydric alcohol, nonyl phenol, polyoxyethylene alcohol, alkylphenol ethoxylate, NEODOLTM, NEODOLTM ethoxylate 91-8, NEODOLTM 67 propoxylated sulphate (N67-7POS), and SYNPERONICTM PE/F68.
  • the metalworking fluid comprises a lubricant.
  • Lubricants may include, but are not limited to, petroleum oil, synthetic oils such as polyalphaolefin (PAO) or phosphate ester, natural esters, synthetic esters, soaps (sodium or potassium), waxes, and boron compounds.
  • PAO polyalphaolefin
  • the metalworking fluid comprises one or more other additives, such as stain inhibitors, corrosion inhibitors, anti-microbial compounds, anti-oxidants, alkanolamines, and phosphate EP additives.
  • the metalworking fluid is thermally stable in a range of about 70 °F to about 250 °F.
  • the metalworking fluid is preferred to be bio-stable, that is, will not readily grow bacteria or fungus when maintained at concentrations above 4% by volume.
  • a typical emulsified oil-in-water metalworking fluid comprises a water phase and oil droplets surrounded or substantially surrounded by emulsifier molecules.
  • the oil molecule may have a negative charge and the emulsifier molecule may have an oleophilic end that is positively charged and a hydrophilic end that is negatively charged.
  • the emulsifier molecules arrange around the oil droplet to provide emulsion droplets having a negatively charged surface.
  • the emulsion droplet size may be in the range of about 1 micron to about 25 micron, about 1 micron to about 20 micron, about 1 micron to about 15 micron, about 1 micron to about 10 micron, or about 1 micron to about 5 micron. In some embodiments the emulsion droplet is at least 1 micron.
  • contaminated metalworking fluid may have positively charged metal particles that are of near micron and/or submicron particle sizes.
  • the positively charged metal particles and the negatively charged emulsion droplets may flocculate, that is join together to form larger particles.
  • air bubbles produced have a slightly negative charge and may associate with the flocculated metal particle and emulsion droplets.
  • application of a shear force causes disruption of the flocculated metal particle and emulsion droplets, and separation of the emulsion droplets from the metal particles.
  • the shear forces briefly dislodge the metal ions from the emulsion surface (e.g., positively charged metal ions from the anionic emulsion surface) and are exchanged, in part, with the dissolved gas (e.g., air) coming out of solution as bubbles (e.g., micro bubbles).
  • the slightly negatively charged micro-bubbles may capture the positive metal micro-particles by electro-kinetic attraction and form together during a laminar flow or a quiescent flow.
  • a method of removing metal particles from a contaminated metalworking fluid includes pressurizing a clean metalworking fluid with gas to provide an aerated metalworking fluid.
  • a clean metalworking fluid may refer to a fresh, unused metalworking fluid, or a metalworking fluid that has been recycled or cleaned of contaminants, such as metal particles.
  • the clean metalworking fluid may be pressurized with gas at a pressure and for a duration sufficient to provide gas bubbles of about 10 micrometers when the pressure is released.
  • the clean metalworking fluid may be pressurized with gas at about 3 bar to about 7 bar, about 3.5 bar to about 6.5 bar, about 3.5 bar to about 6.2 bar, or about 4 bar to about 6 bar for about 2 minutes to about 10 minutes or longer, about 2 minutes to about 5 minutes or longer, about 2 minutes or longer, about 3 minutes or longer, or about 4 minutes or longer.
  • the clean metalworking fluid may be pressurized with gas at about 3.5 bar to about 6.2 bar for about 2 minutes or longer.
  • the clean metalworking fluid may be pressurized with any suitable gas including but not limited to gases comprising nitrogen, oxygen, ozone, or mixtures thereof.
  • the gas may be atmospheric air, such as a mixture of gases including about 75% by weight to about 85% by weight nitrogen and about 15% by weight to about 25% by weight oxygen.
  • the method of removing metal particles from a contaminated metalworking fluid further includes releasing the pressure of the aerated metalworking fluid to form a plurality of gas bubbles.
  • Releasing the pressure may comprise reducing the pressure to about 2.5 bar to about 0.5 bar, about 1.5 bar to about 0.5 bar, or about 1 bar.
  • Releasing the pressure may comprise allowing the pressure of the aerated metalworking fluid to return to atmospheric pressure.
  • the bubbles formed have an average size in a range of from about 10 microns to about 50 microns, about 10 microns to about 40 microns, about 10 microns to about 30 microns, or about 10 microns to about 20 microns.
  • a method of removing metal particles from a contaminated metalworking fluid may further include applying a shear force to the contaminated metalworking fluid to separate the emulsion droplets from the metal particles.
  • the shear force applied is a hydraulic shear force.
  • the applying a hydraulic shear force may include injecting the aerated metalworking fluid into a flow of contaminated metalworking fluid in a direction approximately perpendicular to the flow of contaminated metalworking fluid, for example about 75° to about 105°, about 80° to about 100°, about 85° to about 95°, or about 90° relative to the flow of the contaminated metalworking fluid.
  • the aerated metal working fluid may be injected from the center of the flow of the contaminated metalworking fluid and outward perpendicular into the contaminated metalworking fluid, as for example, shown in Figs. 6A-6B.
  • the aerated metalworking fluid may be injected from the periphery of the flow of the contaminated metalworking fluid and inward toward the center of the flow of the metalworking fluid, as for example, shown in Figs. 7A-7D.
  • the aerated metalworking fluid may be injected via one or more nozzles, and preferably one or more pairs of nozzles, wherein each nozzle in a pair of nozzles is oriented opposite and towards each other.
  • a nozzle provides back pressure between about 50 and about 90 PSIG.
  • the shear force applied is a mechanically generated shear force, for example as shown in Figs. 9A-9B. It is preferable that the formation of the gas bubbles occurs at a location immediately after the point that the high shear forces are applied to the contaminated metalworking fluid so that the metal particles dislodged from the emulsion droplet by the shear forces have an opportunity to combine with the released gas bubbles rather than back to the surface of emulsion droplets.
  • hydraulic shear application of the aerated metalworking fluid can be used in series with mechanical shear equipment. Hydraulic and mechanical methods of shear generating forces are described above, but this is not limited to any particular shear generating device.
  • a method of removing metal particles from a contaminated metalworking fluid may further include flowing the contaminated metalworking fluid with the aerated metalworking fluid in a laminar flow to form a combined fluid.
  • the flowing occurs during the formation of the plurality of bubbles and while the emulsion droplets are separated from the metal particles.
  • the aerated metalworking fluid and the contaminated metalworking fluid are flowed in a flow ratio in a range of about 1 :5 v:v to about 1 : 1 v:v, for example about 1 :3 v:v.
  • the flowing the contaminated metalworking fluid with the aerated metalworking fluid occurs within about 1 second, about 0.9 second, about 0.8 second, about 0.7 second, about 0.6 second, about 0.5 second, about 0.4 second, about 0.3 second, about 0.2 second, about 0.1 second or less after the releasing of the pressure of the aerated metalworking fluid. In some embodiments the flowing occurs within about 1 second, about 0.9 second, about 0.8 second, about 0.7 second, about 0.6 second, about 0.5 second, about 0.4 second, about 0.3 second, about 0.2 second, about 0.1 second or less after the applying the shear force. In some embodiments the flowing occurs at or about the same time as the releasing of the pressure of the aerated metalworking fluid. In some embodiments the flowing occurs at or about the same time as the applying a shear force. In some embodiments the applying a shear force occurs at the same time as the releasing of the pressure of the aerated metalworking fluid.
  • the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles. In some embodiments the laminar flow lasts for about 0.3 second or longer, about 0.4 second or longer, about 0.5 second or longer, about 0.6 second or longer, about 0.7 second or longer, about 0.8 second or longer, about 0.9 second or longer, or about 1 second or longer. In some embodiments the laminar flow lasts for about 0.5 second to about 10 seconds, about 0.5 second to about 8 seconds, about 0.5 second to about 5 seconds, about 1 second to about 5 seconds, about 1 second to about 3 seconds, or about 0.5 second to about 1.5 second.
  • the laminar flow is through a coagulation channel.
  • the length of the coagulation channel is preferably long enough to allow for at least about one second of laminar flow.
  • the coagulation channel is substantially straight to allow for laminar flow with minimal turbulence.
  • a method of removing metal particles from a contaminated metalworking fluid may further include releasing the combined fluid into a flotation tank and removing the metal particles to form a second clean metalworking fluid.
  • removing the metal particles can be by skimming, scooping, or other methods known by persons of skill in the art.
  • the amount of emulsifier in the second clean metalworking fluid is within about 0.1% v/v to about 15% v/v, about 0.1% v/v to about 10% v/v, about 0.1% v/v to about 5% v/v, about 0.1% v/v to about 1% v/v of the amount of emulsifier in the contaminated metalworking fluid.
  • the amount of emulsifier in the second clean metalworking fluid is about 0.1% v/v to about 15% v/v, about 0.1% v/v to about 10% v/v, about 0.1% v/v to about 5% v/v, about 0.1% v/v to about 1% v/v less than the amount of emulsifier in the contaminated metalworking fluid.
  • a method for removing metal particles from a contaminated metalworking fluid includes pressurizing the contaminated metalworking fluid with gas in a pressurization vessel to provide an aerated metalworking fluid, for example as shown in Figs. 11 A- 1 IB.
  • the contaminated metalworking fluid may be pressurized with gas at a pressure and for a duration sufficient to provide gas bubbles of about 10 micrometers when the pressure is released.
  • the contaminated metalworking fluid may be pressurized with gas at about 3 bar to about 7 bar, about 3.5 bar to about 6.5 bar, about 3.5 bar to about 6.2 bar, or about 4 bar to about 6 bar for about 30 seconds to about 10 minutes or longer, about 1 minute to about 5 minutes or longer, about 2 minutes to about 5 minutes or longer, about 1 minute or longer, about 1.5 minutes or longer, about 2 minutes or longer, or about 3 minutes or longer.
  • the contaminated metalworking fluid may be pressurized with gas at about 3.5 bar to about 6.2 bar for about 2 minutes or longer.
  • Gases that may be use include but are not limited to gases comprising nitrogen, oxygen, ozone, or mixtures thereof.
  • the gas may be atmospheric air, such as a mixture of gases including about 75% to 85% nitrogen and about 15%-25% oxygen.
  • a method of removing metal particles from a contaminated metalworking fluid may further include flowing the aerated metalworking fluid from the bottom of the pressurization vessel to a coagulation channel.
  • the bottom of the pressurization vessel refers to the bottom half, bottom one-third, or bottom one-fourth of the pressurization vessel or to the bottom half, bottom one-third, or bottom one-fourth of the aerated metalworking fluid in the pressurization vessel.
  • a method of removing metal particles from a contaminated metalworking fluid may further include applying a shear force to the aerated metalworking fluid to separate the emulsion droplets from the metal particles.
  • the shear force may be a mechanically generated shear force.
  • the method further includes reducing the pressure of the aerated metalworking fluid to provide a plurality of bubbles, wherein the reducing the pressure occurs after applying the shear force and while the emulsion droplets are separated from the metal particles.
  • Releasing the pressure may comprise reducing the pressure to about 2.5 bar to about 0.5 bar, about 1.5 bar to about 0.5 bar, or about 1 bar.
  • Releasing the pressure may comprise allowing the pressure of the aerated metalworking fluid to return to atmospheric pressure.
  • the reducing the pressure occurs within about 1 second, about 0.9 second, about 0.8 second, about 0.7 second, about 0.6 second, about 0.5 second, about 0.4 second, about 0.3 second, about 0.2 second, about 0.1 second or less after the applying the shear force.
  • the bubbles have an average size in a range of from about 10 microns to about 50 microns, about 10 microns to about 40 microns, about 10 microns to about 30 microns, or about 10 microns to about 20 microns.
  • the method further includes flowing the aerated metalworking fluid in a laminar flow through the coagulation channel to a flotation tank.
  • the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles. In some embodiments the laminar flow lasts for about 0.3 second or longer, about 0.4 second or longer, about 0.5 second or longer, about 0.6 second or longer, about 0.7 second or longer, about 0.8 second or longer, about 0.9 second or longer, or about 1 second or longer. In some embodiments the laminar flow lasts for about 0.5 second to about 10 seconds, about 0.5 second to about 8 seconds, about 0.5 second to about 5 seconds, about 1 second to about 5 seconds, about 1 second to about 3 seconds, or about 0.5 second to about 1.5 second.
  • the length of the coagulation channel is preferably long enough to allow for at least about one second of laminar flow. In preferred embodiments, the coagulation channel is substantially straight to allow for laminar flow with minimal turbulence.
  • the method further includes releasing the aerated metalworking fluid into the flotation tank; and removing the metal particles to provide a clean metalworking fluid.
  • the amount of emulsifier in the clean metalworking fluid is within about 0.1 v% to about 15 v%, about 0.1 v% to about 10 v%, about 0.1 v% to about 5 v%, about 0.1 v% to about 1 v% of the amount of emulsifier in the contaminated metalworking fluid.
  • the amount of emulsifier in the clean metalworking fluid is about 0.1 v% to about 15 v%, about 0.1 v% to about 10 v%, about 0.1 v% to about 5 v%, about 0.1 v% to about 1 v% less than the amount of emulsifier in the contaminated metalworking fluid.
  • a method for removing metal particulates from a metalworking fluid described above comprises a phase in a multi-phase purification process.
  • a multi-phase purification process comprises separating large particles, e.g., those greater than about 10 microns, by conventional means such as, basic settling, filtration (gravity, vacuum assist, or pressure assist), hydrocyclones, centrifugation.
  • a multistage purification method comprises flowing contaminated metalworking fluid from a metalworking (e.g., deformation) process into a basic gravity settling tank where the metal particles readily drop out of the continuous solution because of a significant difference of specific gravity of the metallic particle versus the metalworking fluid.
  • the solution overflows to a pump lift station where the contaminated metalworking fluid is injected into a clean (e.g., recycled) fluid and sheared and flowed together, for example as depicted in Figs.
  • the now air and metal particle complex will rise in the flotation tank, where they will be skimmed off, e.g., by skimming rakes.
  • the cleaned fluid moves downward through the flotation tank and may be directed to the pump circuit for the recycle pressurization piping loop or may be returned to the metalworking process.
  • contaminated metalworking fluid from the deformation process enters a basic gravity settling tank where the metal particles readily drop out of the continuous solution because of a significant difference of specific gravity of the metallic particle versus the metalworking fluid.
  • the solution overflows to a pump lift station where a mechanically generated shear is applied to the contaminated metalworking fluid as depicted in Figs. 9A-9B.
  • the shear forces dislodge the positively charged metal ions from the emulsion surface and are exchanged, in part, with the dissolved gas coming out of solution as micro bubbles.
  • the clean metalworking fluid may be directed to the pump circuit for the recycle pressurization piping loop or may be returned for use in the metalworking process, as shown in Figs. 10A-10B. In other embodiments the clean metalworking fluid may be returned for use in the metalworking process only, or the pressurization loop may be eliminated, as shown in Figs. 11 A-l IB.
  • FIG. 6B a system for removing particles from a contaminated metalworking fluid, generally designated (100), in accordance with an exemplary embodiment of the present invention.
  • a pressurization tank (not shown) for pressurizing a clean metalworking fluid with a gas is in fluid connection via conduit (101) with a hydraulic shear device (102).
  • the hydraulic shear device (102) is in fluid connection with a conduit (104) for contaminated metalworking fluid.
  • Conduit (104) is in fluid connection with coagulation channel (103).
  • Hydraulic shear device (102) releases an aerated, pressurized fluid substantially perpendicular to the flow of the contaminated metalworking fluid into coagulation channel (103).
  • Hydraulic shear device (102) comprises inner pipe (105) and outer pipe (106).
  • Inner pipe (105) has a first end (112) and a second end (113).
  • Outer pipe (106) surrounds inner pipe (105) and is approximately coaxial with inner pipe (105).
  • First end cap (107) is sized to seal the first end (112) of the inner pipe (105) and second end cap (108) is sized to seal the second end (113) of the inner pipe (105).
  • Rod (109) has a first end (110) which extends through first end cap (107) and attaches to a pressure adjustment handle (114) and a second end (111) which attaches to second end cap (108).
  • Rod (109) extends through the inner pipe (105) and is capable of pushing the second end cap (108) off of the second end (113) of the inner pipe (105) to release a first fluid (e.g., an aerated fluid) flowing through the inner pipe (105) in a direction perpendicular to a flow of a second fluid (e.g., a contaminated metalworking fluid) through the outer pipe (106), thereby creating shear.
  • a first fluid e.g., an aerated fluid
  • a second fluid e.g., a contaminated metalworking fluid
  • Rod (109) is also capable of pulling the second end cap (108) on the second end (113) of the inner pipe (105) to seal the flow of fluid out of the inner pipe (105) through the second end (113).
  • the movement of rod (109) can be controlled by the pressure adjustment handle (114).
  • the contaminated metalworking fluid and the aerated fluid are contacted through the hydraulic shear and are flowed through the coagulation chamber (103).
  • the coagulation channel may have a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second.
  • Coagulation channel (103) is preferably substantially straight, as shown in Fig. 6B.
  • the coagulation channel (103) is in fluid connection with flotation tank (115). A plurality of gas bubbles is released in the coagulation chamber and cause the metal particles to float towards the top of the fluid in the flotation chamber (104). The metal particles begin to be separated in the flotation chamber (104).
  • An identical system without reference numerals is shown in Fig. 6A.
  • FIG. 7B and 7D there is shown a second embodiment of a system for removing particles from a contaminated metalworking fluid, generally designated (200).
  • the second embodiment is similar to the first embodiment of the system for removing particles from a contaminated metalworking fluid except that the pressurized fluid is injected perpendicular to the flow of the contaminated fluid from the outside of the flow of the contaminated fluid toward the center, thereby creating shear, rather than from the center of the flow of the contaminated fluid.
  • a pressurization tank (not pictured) for pressurizing a clean metalworking fluid with a gas is in fluid connection via conduit (201) with a hydraulic shear device (202).
  • the hydraulic shear device (202) is in fluid connection with a conduit (204) for contaminated metalworking fluid.
  • Conduit (204) is in fluid connection with coagulation channel (203).
  • the hydraulic shear device (202) releases an aerated, pressurized fluid substantially perpendicular to the flow of the contaminated metalworking fluid into coagulation channel (203).
  • Hydraulic shear device (202) comprises nozzle (216) for injecting fluid perpendicular to the direction of coagulation channel (203) and the flow of the contaminated metalworking fluid.
  • Two nozzles (216) are shown in Fig. 1 IB, but any suitable number of nozzles can be used. In some embodiments, nozzles (216) are arranged approximately equidistant around the circumference of the coagulation channel (203).
  • the nozzles are positioned in such a manner to alternate their application of the shear forces by a finite distance positioned in the direction of flow / shear and aimed opposite of each other.
  • two spray nozzles are shown in Figs. 7B and 7D, there can be more nozzles as deemed suitable for this application, preferably if they are in pairs and alternate each other by a finite distance.
  • the contaminated metalworking fluid and the aerated fluid are contacted through the hydraulic shear and are flowed through the coagulation chamber (203).
  • the coagulation channel may have a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second.
  • Coagulation channel (203) is preferably substantially straight, as shown in Figs. 7B and 7D.
  • the coagulation channel (203) is in fluid connection with flotation tank (215).
  • a plurality of gas bubbles is released in the coagulation chamber and cause the metal particles to float towards the top of the fluid in the flotation chamber (204).
  • the metal particles can be removed in the flotation tank (215).
  • An identical system to Fig. 7B without reference numerals is shown in Fig. 7A.
  • An identical system to Fig. 7D without reference numerals is shown in Fig. 7C.
  • the multistage particle removal system (450) includes a conduit (451) for contaminated fluid, such as fluid that has been used in a metalworking process.
  • Conduit (451) is in fluid connection with gravity settling tank (452) which has a sealable opening (453) where large and/or dense particles can be removed after settling in the gravity settling tank (452) due to gravity.
  • Gravity settling tank (452) is in fluid connection with pump lift station (455) via conduit (454).
  • Pump lift station (455) includes a level control (456) which is in electrical connection with pump (457).
  • Pump lift station (455) is in fluid connection with pump (457) and contaminated metalworking fluid can be flowed from the gravity settling tank (452) to the pump lift station (453) and pumped by pump (455) via conduit (404) to the laminar coagulation zone (403) of system (400) for removing particles from a contaminated metalworking fluid.
  • System (400) may in some embodiments be a system utilizing hydraulic shear to separate emulsion droplets from metal particles in the contaminated metalworking fluid, such as the systems shown in Figs. 6 and 7.
  • System (400) includes a pump (417) for sending clean metalworking fluid from flotation tank (415) to an air saturation pressure vessel (also referred to as a pressurization vessel) (418).
  • the clean metalworking fluid is pressurized with a gas, such as (but not limited to) atmospheric air, in the air saturation pressure vessel (418).
  • the pressurization vessel (418) is in fluid connection with a conduit (401) for directing the pressurized or aerated metalworking fluid to the coagulation zone (403).
  • Coagulation channel (403) is preferably substantially straight, as shown in Fig. 8B.
  • System (400) includes a pressure release valve (417) for releasing the pressure in the aerated metalworking fluid and allowing gas bubbles to form.
  • Such pressure release valve (417) may be arranged to provide a hydraulic shear as the aerated metalworking fluid is combined with the contaminated metalworking fluid, for example, as shown in Figs.
  • Coagulation zone (403) is in fluid connection with flotation tank (415) where metal particles can be removed from the fluid, such as by skimming rakes (419). Clean metal working fluid can be flowed from flotation tank ( 15) to the pressurization vessel (418) or via conduit (458) to be used in a metalworking process.
  • An identical system without reference numerals is shown in Fig. 8A.
  • FIG. 9B there is shown a third embodiment of a system for removing particles from a contaminated metalworking fluid, generally designated (300).
  • the third embodiment is similar to the first embodiment of the system for removing particles from a contaminated metalworking fluid except instead of a hydraulic shear device, the third embodiment includes a mechanical shear device (316) for separating emulsion droplets from metal particles.
  • a pressurization tank (301) for pressurizing a clean metalworking fluid with a gas is in fluid connection with an inner pipe (305).
  • Inner pipe (305) has a first end (312) and a second end (313).
  • the second end (313) of inner pipe (305) extends into a coagulation chamber (303).
  • a first end cap (307) is sized to seal the first end (312) of the inner pipe (305) and second end cap (308) is sized to seal the second end (313) of the inner pipe (305).
  • Rod (309) has a first end (310) which extends through first end cap (307) and attaches to a pressure adjustment handle (314) and a second end (311) which attaches to second end cap (308).
  • Rod (309) extends through the inner pipe (305) and is capable of pushing the second end cap (308) off of the second end (313) of the inner pipe (305) to release a first fluid (e.g., an aerated fluid) flowing through the inner pipe (305) into coagulation chamber (303).
  • a first fluid e.g., an aerated fluid
  • Rod (309) is also capable of pulling the second end cap (308) on the second end (313) of the inner pipe (305) to seal the flow of fluid out of the inner pipe (305) through the second end (313).
  • the movement of rod (309) can be controlled by the pressure adjustment handle (314).
  • a contaminated metalworking fluid flows through conduit (304) to mechanical shear device (316) which applies shear to separate emulsion droplets from metal particles in the metalworking fluid.
  • Conduit (304) is in fluid connection with coagulation chamber (303) to allow contaminated metalworking fluid to flow through conduit (304), through mechanical shear device (316) and into coagulation channel (303).
  • coagulation channel (303) is preferably substantially straight.
  • the coagulation channel (303) is in fluid connection with flotation tank (315).
  • a plurality of gas bubbles is released in the coagulation chamber and cause the metal particles to float towards the top of the fluid in the flotation tank (315).
  • the metal particles can be removed in the flotation tank (315).
  • An identical system without reference numerals is shown in Fig. 9A.
  • the multistage particle removal system (550) includes a conduit (551) for contaminated fluid, such as fluid that has been used in a metalworking process.
  • Conduit (551) is in fluid connection with gravity settling tank (552) which has a sealable opening (553) where large and/or dense particles can be removed after settling in the gravity settling tank (552) due to gravity.
  • Gravity settling tank (552) is in fluid connection with pump lift station (555) via conduit (554).
  • Pump lift station (555) includes a level control (556) which is in electrical connection with pump (557).
  • Pump lift station (555) is in fluid connection with pump (557) and contaminated metalworking fluid can be flowed from the gravity settling tank (552) to the pump lift station (553) and pumped by pump (555) via conduit (504) to the laminar coagulation zone (503) of system (500) for removing particles from a contaminated metalworking fluid.
  • System (500) may in some embodiments be a system utilizing mechanically generated shear to separate emulsion droplets from metal particles in the contaminated metalworking fluid, such as the system shown in Figs. 9A-9B.
  • System (500) includes a pump (517) for sending clean metalworking fluid from flotation tank (515) to an air saturation pressure vessel (also referred to as a pressurization vessel) (518).
  • the clean metalworking fluid is pressurized with a gas, such as (but not limited to) atmospheric air, in the air saturation pressure vessel (518).
  • the pressurization vessel (518) is in fluid connection with a conduit (501) for directing the pressurized or aerated metalworking fluid to the coagulation zone (503).
  • Coagulation channel (503) is preferably substantially straight, as shown in Fig. 10B.
  • System (500) includes a pressure release valve (517) for releasing the pressure in the aerated metalworking fluid and allowing gas bubbles to form.
  • Coagulation zone (503) is in fluid connection with flotation tank (515) where metal particles can be removed from the fluid, such as by skimming rakes (519). Clean metal working fluid can be flowed from flotation tank (515) to the pressurization vessel (518) or via conduit (558) to be used in a metalworking process.
  • An identical system without reference numerals is shown in Fig. 10A.
  • Fig. 1 IB shows a system similar to Figs. 10A-10B, except that the clean metal working fluid is flowed only from flotation tank (615) to be used in a metalworking process.
  • a multistage particle removal system (650) includes a conduit (651) for contaminated fluid, such as fluid that has been used in a metalworking process.
  • Conduit (651) is in fluid connection with gravity settling tank (652) which has a sealable opening (653) where large and/or dense particles can be removed after settling in the gravity settling tank (652) due to gravity.
  • Gravity settling tank (652) is in fluid connection with pump lift station (655) via conduit (654).
  • Pump lift station (655) includes a level control (656) which is in electrical connection with pump (657). Pump lift station (655) is in fluid connection with pump (657) and contaminated metalworking fluid can be flowed from the gravity settling tank (652) to the pump lift station (653) and pumped by pump (655) to an air saturation pressure vessel (also referred to as a pressurization vessel) (618).
  • the contaminated metalworking fluid is pressurized with a gas, such as (but not limited to) atmospheric air, in the air saturation pressure vessel (618).
  • the pressurization vessel (618) is in fluid connection with a conduit (604) for directing the pressurized or aerated metalworking fluid to the coagulation channel (603).
  • Coagulation channel (603) is preferably substantially straight, as shown in Fig. 1 IB.
  • System (600) includes a mechanical shear device (616) to induce a shear force to separate emulsion droplets from metal particles in the contaminated metalworking fluid and pressure release valve (617) for releasing the pressure in the aerated metalworking fluid and allowing gas bubbles to form.
  • the pressure valve (617) is located immediately after the mechanical shear device (616) so that the emulsion droplets are still separated from the metal particles when the gas bubbles formed and the metal particles are free to associate with the gas bubbles in the coagulation zone (603).
  • Coagulation zone (603) is in fluid connection with flotation tank (615) where metal particles can be removed from the fluid, such as by skimming rakes (619). Clean metal working fluid can be flowed from flotation tank (615) via conduit (658) to be used in a metalworking process.
  • An identical system without reference numerals is shown in Fig. 11 A.
  • a method of removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles comprising: pressurizing a first clean metalworking fluid with gas to provide an aerated metalworking fluid; releasing the pressure of the aerated metalworking fluid to form a plurality of bubbles; applying a shear force to the contaminated metalworking fluid to separate the emulsion droplets from the metal particles; flowing the contaminated metalworking fluid with the aerated metalworking fluid in a laminar flow to form a combined fluid, wherein the flowing occurs during the formation of the plurality of bubbles and while the emulsion droplets are separated from the metal particles, and wherein the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles; releasing the combined fluid into a flotation tank; and removing the metal particles to form a second clean metalworking fluid.
  • a method for removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles comprising: pressurizing the contaminated metalworking fluid with gas in a pressurization vessel to provide an aerated metalworking fluid; flowing the aerated metalworking fluid from the bottom of the pressurization fluid to a coagulation channel; applying a shear force to the aerated metalworking fluid to separate the emulsion droplets from the metal particles; reducing the pressure of the aerated metalworking fluid to provide a plurality of bubbles, wherein the reducing the pressure occurs after applying the shear force and while the emulsion droplets are separated from the metal particles; flowing the aerated metalworking fluid in a laminar flow through the coagulation channel to a floatation tank, wherein the laminar flow lasts for a time sufficient for the plurality of bubbles to attach to the metal particles; releasing the aerated metalworking fluid into the flotation tank; and removing the metal
  • Clause 3 The method of clause 1, wherein the contacting occurs within about 0.5 second or less after the releasing of the pressure of the aerated metalworking fluid.
  • Clause 4 The method of clause 1, wherein the wherein the flowing occurs within about 0.5 second or less after applying the shear force.
  • Clause 7 The method of clause 2, wherein the reducing the pressure is about 0.5 second or less after applying the shear force.
  • Clause 8 The method of clause 2, wherein the reducing the pressure occurs within 0.5 second after applying the shear force.
  • Clause 10 The method of clause 1 or 2, wherein the time sufficient for the plurality of bubbles to attach to the metal particles is at least about 1.0 second.
  • Clause 11 The method of clause 1 or 2, wherein the metal particles have an average particle size of about 30 micron or less.
  • Clause 12 The method of clause 1, wherein the first clean metalworking fluid is pressurized with gas at about 3.5 bar to about 6.2 bar for about two minutes or longer.
  • Clause 13 The method of clause 2, wherein the clean metalworking fluid is pressurized with gas at about 3.5 bar to about 6.2 bar for about two minutes or longer.
  • Clause 14 The method of clause 1 or 2, wherein the aerated metalworking fluid and the contaminated metalworking fluid are flowed in a flow ratio in a range of 1 :5 (v:v) to 1 : 1 (v:v).
  • Clause 15 The method of clause 1 or 2 wherein the metal particles are non-ferrous.
  • Clause 16 The method of clause 15, wherein the metal particles comprise one or more of copper, aluminum, nickel, lead, titanium, tungsten and molybdenum.
  • Clause 17 The method of clause 1 or 2, wherein the gas comprises atmospheric air.
  • Clause 18 The method of clause 1 or 2, wherein the gas is selected from nitrogen, oxygen, and ozone.
  • Clause 19 The method of clause 1 or 2, wherein the contaminated metalworking fluid comprises an anionic emulsifier.
  • Clause 20 The method of clause 1 or 2, wherein the contaminated metalworking fluid comprises a nonionic emulsifier.
  • Clause 21 The method of clause 1 or 2, wherein the contaminated metalworking fluid comprises an anionic emulsifier and a nonionic emulsifier.
  • Clause 22 The method of clause 21, wherein the nonionic emulsifier is present at about 0.1% wt. to 20% wt of the anionic emulsifier.
  • Clause 23 The method of clause 1 or 2, wherein the bubbles have a size in a range of from about 10 microns to about 50 microns.
  • Clause 24 The method of clause 1 or 2, wherein the contaminated metalworking fluid is an oil-in-water phase emulsion.
  • Clause 25 The method of clause 24, wherein the emulsion comprises emulsion droplets having a size in a range of about 10 microns to 1 micron.
  • Clause 26 The method of clause 1 or 2, wherein the contaminated metalworking fluid is a water-in-oil phase emulsion.
  • Clause 27 The method of clause 1 or 2, wherein the metalworking process is a metal forming or metal removal process.
  • Clause 29 The method of clause 1, wherein the amount of emulsifier in the second clean metalworking fluid is within about 0.1% v/v to about 15% v/v of the amount of emulsifier in the contaminated metalworking fluid.
  • Clause 30 The method of clause 2, wherein the amount of emulsifier in the clean metalworking fluid is within about 0.1% v/v to about 15% v/v of the amount of emulsifier in the contaminated metalworking fluid.
  • a system for removing particles from a contaminated metalworking fluid comprising: a pressurization tank; a mechanical shear device; a coagulation channel having a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second; and a flotation tank.
  • a system for removing particles from a contaminated metalworking fluid comprising: a pressurization tank; a hydraulic shear device; a coagulation channel having a length sufficient to provide a laminar flow of a fluid through the coagulation chamber for at least about 1 second; and a flotation tank.
  • the hydraulic shear device comprises: an inner pipe; an outer pipe surrounding the inner pipe and approximately coaxial with the inner pipe; a first end cap and a second end cap, each sized to seal an end of the inner pipe; a rod having a first end and a second end and extending through the inner pipe and the through the first end cap, the second end of the rod being connected to the second end cap, wherein the rod is capable of pushing the end cap off of the second end of the inner pipe to release a first fluid flowing through the inner pipe in a direction perpendicular to a flow of a second fluid through the outer pipe, and wherein the rod is capable of pulling the end cap on the second end of the inner pipe to seal the flow of fluid out of the inner pipe through the second end.
  • the hydraulic shear device comprises: a pipe; and a nozzle for injecting a fluid perpendicular to the direction of the pipe.

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  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
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Abstract

L'invention concerne un procédé d'élimination des particules métalliques d'un fluide de travail des métaux contaminé contenant des gouttelettes d'émulsion et des particules métalliques, comprenant : la mise sous pression d'un premier fluide de travail des métaux propre avec un gaz pour obtenir un fluide de travail des métaux aéré ; le relâchement de la pression du fluide de travail des métaux aéré pour former une pluralité de bulles ; l'application d'une force de cisaillement au fluide de travail des métaux contaminé pour séparer les gouttelettes d'émulsion des particules métalliques ; l'écoulement du fluide de traitement des métaux contaminé avec le fluide de traitement des métaux aéré dans un écoulement laminaire pour former un fluide combiné, l'écoulement se produisant pendant la formation de la pluralité de bulles et pendant que les gouttelettes d'émulsion sont séparées des particules métalliques, et l'écoulement laminaire durant un temps suffisant pour que la pluralité de bulles se fixe aux particules métalliques ; le déversement du fluide combiné dans un réservoir de flottation ; et l'élimination des particules métalliques pour former un second fluide de traitement des métaux propre.
PCT/US2022/026970 2022-04-29 2022-04-29 Systèmes et procédés d'élimination de microparticules d'un fluide de travail de métaux WO2023211463A1 (fr)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492636A (en) * 1983-02-11 1985-01-08 Eaton Corporation Process for cleaning metal working fluids for re-use
US4535943A (en) * 1983-05-18 1985-08-20 The Black Clawson Company Pulping apparatus including a rotor and helical screw flights extending upwardly from the rotor
US5137654A (en) * 1991-10-17 1992-08-11 Eaton Corporation Process for reclaiming oil/water emulsion
WO2001045818A1 (fr) * 1999-12-22 2001-06-28 Robert Scalliet Procede de rupture d'une emulsion
US20160326017A1 (en) * 2013-12-30 2016-11-10 Houghton Technical Corp. Dissolved air flotation use with cationic metal processing fluids
WO2019211481A1 (fr) * 2018-05-03 2019-11-07 Wilds Ivan Mark Appareil de décontamination de fluide de travail métallique
US20210017263A1 (en) * 2018-03-30 2021-01-21 Sekisui Medical Co., Ltd. Monoclonal antibody specifically reacting with dupan-2 antigen and method for producing same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492636A (en) * 1983-02-11 1985-01-08 Eaton Corporation Process for cleaning metal working fluids for re-use
US4535943A (en) * 1983-05-18 1985-08-20 The Black Clawson Company Pulping apparatus including a rotor and helical screw flights extending upwardly from the rotor
US5137654A (en) * 1991-10-17 1992-08-11 Eaton Corporation Process for reclaiming oil/water emulsion
WO2001045818A1 (fr) * 1999-12-22 2001-06-28 Robert Scalliet Procede de rupture d'une emulsion
US20160326017A1 (en) * 2013-12-30 2016-11-10 Houghton Technical Corp. Dissolved air flotation use with cationic metal processing fluids
US20210017263A1 (en) * 2018-03-30 2021-01-21 Sekisui Medical Co., Ltd. Monoclonal antibody specifically reacting with dupan-2 antigen and method for producing same
WO2019211481A1 (fr) * 2018-05-03 2019-11-07 Wilds Ivan Mark Appareil de décontamination de fluide de travail métallique

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