Title:
TREATMENT METHOD AND TREATMENT APPARATUS FOR WASTE WATER CONTAINING SULFURIC ACID, FLUORINE AND HEAVY METAL IONS
Document Type and Number:
WIPO Patent Application WO/2018/092396
Kind Code:
A1
Abstract:
According to the present invention, a pretreated water is produced by adding a calcium fluoride precipitation inhibitor into a waste water that contains sulfuric acid, fluorine (fluoride ions or hydrogen fluoride) and heavy metal ions. Subsequently, a first insolubilized product is produced and solid-liquid separated at a pH of less than 5 by adding a calcium compound into the pretreated water; a second insolubilized product is produced and solid-liquid separated at a pH of 3-7 (provided that this pH is higher than the pH in the first reaction step) by adding a calcium compound into a first separated water obtained by the solid-liquid separation in the preceding step; and a third insolubilized product is produced and solid-liquid separated by adding an alkali into a second separated water obtained by the solid-liquid separation in the preceding step so that the pH thereof is 8 or more.
Inventors:
IZAWA SHUHEI (JP)
TANAKA IPPEI (JP)
TANAKA IPPEI (JP)
Application Number:
PCT/JP2017/032797
Publication Date:
May 24, 2018
Filing Date:
September 12, 2017
Export Citation:
Assignee:
KURITA WATER IND LTD (JP)
International Classes:
C02F1/58; C02F1/62
Foreign References:
| JPS62197192A | 1987-08-31 | |||
| JP2007196177A | 2007-08-09 | |||
| JP2011200788A | 2011-10-13 | |||
| JPS6097090A | 1985-05-30 |
Attorney, Agent or Firm:
SHIGENO, Tsuyoshi et al. (JP)
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