Title:
PROCESS FOR PURIFYING A SODIUM SULFATE RESIDUE
Document Type and Number:
WIPO Patent Application WO/2020/233558
Kind Code:
A1
Abstract:
Provided is a process for purifying a sodium sulfate residue comprising sodium sulfate, sodium carbonate and sodium chloride, and optionally insoluble matter. The process comprises: (a) dissolving the residue with a first aqueous solution to obtain a first aqueous suspension comprising at least 5 wt% and at most 32 wt% of sodium sulfate; (b) optionally separating the insoluble matter from the first aqueous suspension to obtain a separated insoluble matter and a second aqueous solution; (c1) acidifying the second aqueous solution with sulfuric acid to a pH of less than 6 so as to transform at least part or all of dissolved sodium carbonate to sodium sulfate; (c2) optionally aerating the acidified second aqueous solution with oxygen or air to convert sulfites to sulfates; (c3) alkalinizing the acidified second aqueous solution to a pH of about 7 or more with an alkali; (d) removing part of the water from the second aqueous solution to obtain a mother liquor and to crystallize sodium sulfate; (f) purging part of the mother liquor and recycling part of the non-purged mother liquor in at least one of the steps (a) to (d), wherein a weight ratio of the purged separated mother liquor to the non-purged separated mother liquor is at most 0.20 t/t. Also provided is a use of sodium sulfate particles obtained from the process.
Inventors:
WOOD MICHAEL (US)
WANG YAN (CN)
BEDEL SABRINA (FR)
CRIADO CLAUDE (FR)
WANG AIPING (CN)
WANG YAN (CN)
BEDEL SABRINA (FR)
CRIADO CLAUDE (FR)
WANG AIPING (CN)
Application Number:
PCT/CN2020/090982
Publication Date:
November 26, 2020
Filing Date:
May 19, 2020
Export Citation:
Assignee:
SOLVAY (BE)
International Classes:
C01D5/16
Foreign References:
| US6180074B1 | 2001-01-30 | |||
| CN1738787A | 2006-02-22 | |||
| CN108658353A | 2018-10-16 | |||
| CN104356007A | 2015-02-18 | |||
| CN105906126A | 2016-08-31 | |||
| CN103450287A | 2013-12-18 | |||
| US5135734A | 1992-08-04 | |||
| US6180074B1 | 2001-01-30 |
Other References:
See also references of EP 3972936A4
Attorney, Agent or Firm:
CHINA PATENT AGENT (H.K.) LTD. (CN)
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