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Detergent‐hard water interactions in machine dishwashing
Author(s) -
Vance Robert F.
Publication year - 1969
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02540618
Subject(s) - calcium , chemistry , silicate , ionic bonding , chelation , inorganic chemistry , chemical engineering , mineralogy , ion , organic chemistry , engineering
Insufficient detergent concentration has recently been recognized as a major contributor to film formation on glassware in machine dishwashing. The film is shown to consist largely of calcium tripolyphosphate, Ca 5 (P 3 O 10 ) 2 ; evidence is cited for the presence of a silicate, probably calcium metasilicate, as well. Systematic variation of detergent concentration and of water hardness allows construction of a response surface describing conditions of maximum and minimum rates of film formation. The extent of film formation is minimized when the ionic ratio of Ca or Mg or both to tripolyphosphate is 1:1 and maximized when the ratio is 5:2. These ratios correspond to the 1:1 chelate and the uncharged precipitate, Ca 5 (P 3 O 10 ) 2 , respectively. The implications of this treatment to other detergency processes are also considered.