A system and process for recycling machining waste into a solid/scrap material component and a recyclable machining coolant. The system and process comprise collecting the waste machining waste and mechanically separating the machining waste into a solid/scrap material component and a machining waste liquid component. The machining waste liquid component is decanted to separate oils and solids from the recyclable machining coolant. The machine recyclable machining coolant is then filtered through at least a first filter and preferably a second, finer mesh filter. The recyclable machining coolant is then exposed to UV light to kill bacteria and microorganisms. Lastly, ultrapure water is added to dilute the recyclable machining coolant and form the recycled machining coolant. If desired, a virgin machining coolant can be added to the recycled machining coolant, to replenish any additive(s) stripped during the recycling process, prior to resale of the recycled machining coolant.

A method of removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles includes 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 of removing metal particles from a contaminated metalworking fluid comprising emulsion droplets and metal particles includes 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 system and process for recycling machining waste into a solid/scrap material component and a recyclable machining coolant. The system and process comprise collecting the waste machining waste and mechanically separating the machining waste into a solid/scrap material component and a machining waste liquid component. The machining waste liquid component is decanted to separate oils and solids from the recyclable machining coolant. The machine recyclable machining coolant is then filtered through at least a first filter and preferably a second, finer mesh filter. The recyclable machining coolant is then exposed to UV light to kill bacteria and microorganisms. Lastly, ultrapure water is added to dilute the recyclable machining coolant and form the recycled machining coolant. If desired, a virgin machining coolant can be added to the recycled machining coolant, to replenish any additive(s) stripped during the recycling process, prior to resale of the recycled machining coolant.

The invention relates to the use of one or more M-methyl-N-acylglucamines of the formula (I) wherein R.sup.1 represents a linear or branched, saturated or unsaturated hydrocarbon group having 7 to 21 carbon atoms, as a corrosion inhibitor.

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Provided is a method for recycling a cold-rolled oil sludge, including the following steps: mixing methanol with the cold-rolled oil sludge to obtain a mixture, and subjecting the mixture to esterification under supercritical conditions to obtain a solid-liquid mixture; subjecting the solid-liquid mixture to solid-liquid separation to obtain an iron filing and a liquid phase; and subjecting the liquid phase to methanol removal and extraction in sequence to obtain an oil phase product and an aqueous phase product.

Provided is a method for recycling a cold-rolled oil sludge, including the following steps: mixing methanol with the cold-rolled oil sludge to obtain a mixture, and subjecting the mixture to esterification under supercritical conditions to obtain a solid-liquid mixture; subjecting the solid-liquid mixture to solid-liquid separation to obtain an iron filing and a liquid phase; and subjecting the liquid phase to methanol removal and extraction in sequence to obtain an oil phase product and an aqueous phase product.