Water-soluble cutting fluid for slicing silicon ingots

A water-soluble cutting fluid for slicing silicon ingots characterized in comprising an azelaic acid (A), either a polyprotic organic acid (B) with ΔpKa of 0.9˜2.3 as defined by the following formula (1) or an inorganic alkali salts (BA3) of said polyprotic organic acid (B) as essential components, a compound (C), a 50 wt % potassium hydroxide aqueous solution as a pH adjusting agent (D), a naphthalene sulfonic acid formalin condensate as a dispersant (E), and a water:

• ΔpKa=(pKa2)−(pKa1) (1)
• wherein said polyprotic organic acid (B) comprises citric acid, phthalic acid, or isophthalic acid, said inorganic alkali salts (BA3) comprises citrate salts, phthalate salts, or isophthalate salts having a base derived from lithium, sodium, potassium, calcium, or magnesium, and a dissociation stage, at which said polyprotic organic acid (B) denoted as n-protic acid HnA becomes Hn-1A+H+, is numbered as 1 with an acid dissociation constant expressed as pKa1, and the dissociation stage at which said polyprotic organic acid (B) becomes Hn-2A+H+ is numbered as 2 with an acid dissociation constant expressed as pKa2;
• wherein said compound (C) is propylene glycol,
• wherein relative to said cutting fluid for slicing silicon ingots, the content of said compound (C) in the said cutting fluid is 60 to 90 wt %.