REGENERATED COOLANT AND COOLANT REGENERATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a regenerated coolant and a coolant regeneration method in which the ratio of silicon particulates with a particle size of 0.1 μm or smaller is reduced.

SOLUTION: The coolant regeneration method 1a includes: a coolant supply step S1 of supplying a used coolant 3 to a centrifugation unit 2; a centrifugation step S2 of centrifuging the used coolant 3; a centrifugation liquid recovery step S3 of recovering a centrifugation liquid 19 which is separated; a centrifugation liquid supply step S5 of supplying the centrifugation liquid 5 to a membrane separation unit 7; a membrane separation step S6 of membrane-separating the centrifugation liquid 19; and a membrane filtrate recovery step S7 of recovering a membrane filtrate 21 which is separated. The regenerated coolant 4 has a residual silicon component of 0.01 wt.% or larger and 3.0 wt.% or smaller relative to the whole regenerated coolant, and silicon particulates with a particle size of 0.1 μm or smaller which are contained in the residual silicon component is 0.01 wt.% or larger and 30 wt.% or smaller relative to the whole residual silicon component.

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