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Phosphonates stain-less steel

Phosphonic acid and phosphonates are fine water softeners. Phosphonate molecules are characterized by adjacent phosphoric and oxygen atoms: P=O-OH. They dissolve readily in water, are chemically stable (no reaction with other ingredients) and function also at higher temperatures.

How do phosphonates soften lime containing water?

Lime containing (hard) water contains Calcium salts. Positive ions like Calcium (Ca2+) fit perfectly into the charge division and 3-dimensional formation of phosphonate molecules. Each phosphonate molecule can encapsulate exactly one Calcium ion. Phosphonates removes Calcium ions from the water, so they cannot form Calcium (lime) scale any more. The Calcium disappears together with the phosphonate in the washing water.

How do phosphonates fight corrosion?

Corrosion is oxidized metal. In the same way phosphonic acids and phosphonates soften water; they also have the ability to retain other metal ions. The phosphonates approach the metal surface and try to encapsulate the metal ions; the same way they do with Calcium. The metal ions are fixed in the metal; the phosphonates cannot detach them. But by gathering on the metal surface the phosphonates do fence of the metal against the oxidizing influence of water and oxygen. So phosphonates are anti-corrosive by forming a thin layer on top of metal surfaces.

This is how phosphonates fight scaling and corrosion. This is not only handy to protect (dish) washing machines, but also in other water treatment equipment. Phosphonates are therefore added to industrial water, heat exchangers and heating installations. Especially in open systems. Because water evaporates from open systems, leaving behind Calcium and other ions in ever increasing cocentrations. In such systems the addition of phosphonates becomes even more important.


Their chemical stability also makes phosphonic acid and phosphonates badly biodegradable. Fortunately they are easily removed in water/sewage treatment. Therefore they are allowed everywhere.


The Sirius effect

Sirius supplies a numbe rof synergistic products for use in detergents as well as water treatment. Formulators recognize the universal abbreviations for these products:


  • Phosphon acid              ATMP      HEDP         EDTMP       DTPMP     PBTC       HPAA
  • Phosphonate                ATMP.Na HEDP.Na    EDTMP.Na  DTPMP.Na    PBTC.Na
    ATMP.K   HEDP.K                    HMDTMPA.K
  • Phosphate      STPP       TKPP
  • Polyacrylate   PAA         PAAS       HPMA       MA/AA, AA/AMPS        PCA
  • Biocide           Triclosan Pyrithion


Enter into discussion with us so we can indicate how this Group of product functions and keeps your and your clients equipment clean.

Tel: +31(0)35 54 85 899


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