TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The fine particles of greater than 2 mu m in size is removed using a high-speed centrifuge at 50-60 degrees C under 3500-4500 revolutions per minute. The waste cutting fluid is heated by steam to maintaining its temperature within 50-70 degrees C for viscosity reduction and filtration efficiency enhancement. The used membrane is pipe shaped for high viscosity of greater 100000 centipoise and with a pore size of 0.05 -0.1 mu m and pH of 1-14, and solid concentration of 50 %, where the membrane is made of polymer, ceramic or metal materials. The waste cutting fluid removal is performed by glycols including ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethyleneglycol, tetraethylene glycol, butylene glycol, hexylene glycol, glycerin, polyethylene glycol, polypropylene glycol, polybutyleneglycol, and poly hexylene glycol, where the waste cutting fluid is distilled water. The method further comprises lowering the moisture amount within the waste cutting fluid. The method further comprises performing filtration membrane salvage process to remove the metallic impurities, and then performing wetting process. The method further performs cutting scrap removal step using the membrane and lowering contents of the cutting liquid and circulating the filtrate with a mixing buffer bath to increase the recovery rate of the high purity regeneration cutting liquid through the additional separate operation. The moisture content is maintained as 0.2% among the regeneration cutting liquid. The method further comprises performing pre evaporation membrane process to selectively remove the moisture. The method further comprises inserting inert gas into a top of a direct tank using an inert gas generator. The centrifuge comprises a high speed centrifuge, a vertical cylinder centrifuge, a decanter, a precoat form or disc type filter presser with pore size of 1-500 mu m. The filter uses micropowder including diatomite, pearlite, ion-exchange resin, where filter aid layer is 3-5 mm in size.