METHOD FOR PREVENTING CALCIUM SCALE

WIPO Patent Application WO/2013/021475

A1

[Problem] To provide a method for preventing calcium scale whereby chemical cost can be reduced and operation cost can be saved. [Solution] A method for preventing calcium scale, which comprises: by using an amphoteric ion-exchange resin (4), separating waste water, which induces the formation of calcium scale, into first solution (L4), said first solution (L4) having a low calcium ion concentration and containing harmful matters at a high concentration, and second solution (L3), said second solution (L3) having a high calcium ion concentration and containing harmful matters at a low concentration; and separately treating the first and second solutions. The timing of switching the first solution and the second solution, that are discharged from the amphoteric ion-exchange resin, can be controlled on the basis of one or more factors selected from among the COD concentration of the solution discharged from the amphoteric ion-exchange resin, the calcium ion concentration thereof, the chlorine ion concentration thereof and the electric conductivity thereof. As the waste water inducing the formation of calcium scale, leachate (W1) from a final disposal plant, filtrate obtained by washing burned ash with water, or filtrate obtained by washing chlorine bypass dust with water can be used.

TAMURA NORITOSHI (JP)
OTANI HIROKAZU (JP)

PCT/JP2011/068232

February 14, 2013

August 10, 2011

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TAIHEIYO CEMENT CORP (JP)
TAMURA NORITOSHI (JP)
OTANI HIROKAZU (JP)

C02F5/00; B01J49/00; B09B3/00; C02F1/42

JPS5273545A	1977-06-20
JP2005052738A	2005-03-03
JP2007125484A	2007-05-24
JP2002146691A	2002-05-22
JPS5942083A	1984-03-08
JP2009090256A	2009-04-30
JP4766719B1	2011-09-07

NAKAI JUN (JP)
Nakai 潤 (JP)

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