Title:
PURIFICATION METHOD FOR ELECTRONIC-GRADE CITRIC ACID
Document Type and Number:
WIPO Patent Application WO/2023/226619
Kind Code:
A1
Abstract:
Provided in the present invention is a purification method for an electronic-grade citric acid. The method comprises dissolving industrial-grade solid citric acid having a relatively high impurity content to formulate a dilute citric acid solution having a concentration (in percentages by mass) of 10-30%; by using an appropriate resin, purifying the solution through a column by means of a peristaltic pump at the rate larger than 0 Bv/h and smaller than or equal to 3 Bv/h; concentrating the dilute citric acid solution, which has been purified through the column, in a rotary evaporator at 60-80ºC into a concentrated citric acid solution having a concentration of 70-80%; cooling the concentrated citric acid solution at a certain rate to 30-40ºC; adding a seed crystal, and cooling same to 20ºC or below at a certain rate; and washing, filtering and dissolving crystals. By means of the method, the content of one or more metal ions, such as K+, Ca2+, Na+, Mg2+ and Al3+, can be reduced to 10 ppb or below; the content of one or more metal ions other than those mentioned above, such as Mn2+, Fe2+, Ni2+ and Cu2+, can be reduced to 5 ppb or below; and the obtained electronic-grade citric acid has a high purity and can be used in semiconductor, medical and other fields that have extremely stringent requirements for the purity of citric acid.
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| WO/1996/008459 | PROCESS FOR RECOVERING CITRIC ACID |
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Inventors:
LI SHAOPING (CN)
YE RUI (CN)
HE ZHAOBO (CN)
WANG RONG (CN)
ZHANG TING (CN)
PENG JUNJIE (CN)
OUYANG KEYIN (CN)
ZHANG LING (CN)
WU WENJING (CN)
LI QIN (CN)
YE RUI (CN)
HE ZHAOBO (CN)
WANG RONG (CN)
ZHANG TING (CN)
PENG JUNJIE (CN)
OUYANG KEYIN (CN)
ZHANG LING (CN)
WU WENJING (CN)
LI QIN (CN)
Application Number:
PCT/CN2023/088576
Publication Date:
November 30, 2023
Filing Date:
April 17, 2023
Export Citation:
Assignee:
HUBEI SINOPHORUS ELECTRONIC MAT CO LTD (CN)
International Classes:
C07C51/47; C07C51/43; C07C59/265
Domestic Patent References:
| WO1996008459A1 | 1996-03-21 |
Foreign References:
| CN114890889A | 2022-08-12 | |||
| CN101973871A | 2011-02-16 | |||
| GB905817A | 1962-09-12 |
Other References:
DEXIN HAN, GAO NIANFA; ZHOU YAWEN: "Research Progress of Citric Acid Extraction Technology", HANGZHOU CHEMICAL INDUSTRY, vol. 39, no. 3, 15 October 2009 (2009-10-15), pages 3 - 7, XP093111782, ISSN: 1007-2217
Attorney, Agent or Firm:
YICHANG THREE GORGES PATENT (CN)
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