| 摘要 |
<p>Circulating water (esp. water cooling systems, heat exchangers and evaporators) is conditioned for lowering corrosive attacks and boiler scale on metal surfaces by incorporating a mixt. contg. 0.5-50 (2-10) p.p.m. of a 1-hydroxyalkylidene-1,1-diphosphonic acid of formula (MO)2-PO-CR(OH)-PO(OM)2 (where R is 1-5C alkyl and M is H, a metal cation, NH4+ or an ethanolammonium ion) in addn. to 1-200 (10-60) p.p.m. of a water-soluble polyphosphate (calc. as PO4) consisting of (1) an inorganic polyphosphate with an 0.4:1 to 2:1 mol. ratio of s=1 alkali-, alkaline earth metal- and/or Zn oxide to P2O5 and/or its corresp. acid with a 0.4:1 to 2:1 water:P2O5 mol. ratio, or (2) a polyfunctional acid phosphate ester of a polyhydric alcohol having formula R-(OPO3H2)x (where R is the hydrocarbyl gp. of a polyhydric alcohol and x is 2 to 6).</p> |
