CN115057419A - Industrial-grade wet-process phosphoric acid dearsenification method - Google Patents
Industrial-grade wet-process phosphoric acid dearsenification method Download PDFInfo
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- CN115057419A CN115057419A CN202210632076.0A CN202210632076A CN115057419A CN 115057419 A CN115057419 A CN 115057419A CN 202210632076 A CN202210632076 A CN 202210632076A CN 115057419 A CN115057419 A CN 115057419A
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- phosphoric acid
- arsenic
- hydrogen sulfide
- sulfide
- packed tower
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/238—Cationic impurities, e.g. arsenic compounds
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Abstract
The invention discloses an industrial-grade wet-process phosphoric acid dearsenification method, which comprises the following steps: 1) mixing sodium sulfide and raw material phosphoric acid in a hydrogen sulfide generator at the bottom of the filler dearsenification tower, keeping the temperature of the reactor at 60 +/-2 ℃, and reacting for 15 min; 2) introducing hydrogen sulfide gas generated by the reaction into the arsenic removal packed tower through an exhaust pipe at the top of the generator; 3) hydrogen sulfide gas enters a tail gas pipeline from bottom to top through a packed tower under the action of a tail gas fan, arsenic-containing phosphoric acid with other impurities removed overflows from the upper part of the packed tower and is subjected to countercurrent contact reaction to generate arsenic sulfide precipitate, so that arsenic in the phosphoric acid is removed; 4) discharging the generated sodium phosphate solution to a collecting tank through an overflow pipe; 5) filtering the dearsenized mixed phosphoric acid mother liquor to obtain the product. The method has the advantages that the sodium sulfide and the phosphoric acid are subjected to countercurrent contact reaction in the packed tower, the mass transfer effect is good, the reaction is sufficient, the material consumption is low, the arsenic removal effect is good, and the arsenic content of the final product is less than 1 ppm.
Description
Technical Field
The invention relates to industrial-grade phosphoric acid, in particular to a method for removing arsenic from industrial-grade wet-process phosphoric acid.
Background
The existing wet-process phosphoric acid dearsenification technology is that sodium sulfide is added into a reactor and stirred and mixed by a stirrer to react to produce arsenic sulfide insoluble substances, and a specific reaction equation is as follows:
in the prior art, a sodium sulfide pipeline is inserted into a reactor, and a small hole is formed in an insertion pipe so that sodium sulfide and phosphoric acid are mixed under the stirring condition. By adopting the method, the small holes of the sodium sulfide insertion tube are easy to block; the content of F in the phosphoric acid is high, the corrosion is easy to occur, and the stirrer is damaged after the insertion pipe is broken; a gas phase pipe in the reactor is directly connected with a tail gas washing system, on one hand, hydrogen sulfide escaped from the reaction is not fully utilized, on the other hand, the reactor maintains micro-negative pressure operation, the solubility of the hydrogen sulfide in acid is not high, the consumption of sodium sulfide is large, the sodium sulfide is directly added into phosphoric acid, wherein sodium element cannot be removed in the subsequent purification process, and the application of industrial grade phosphoric acid is seriously influenced.
Disclosure of Invention
The invention aims to solve the technical problem and provides an industrial-grade wet-process phosphoric acid dearsenification method. The invention utilizes the working principle of a packed tower to react sodium sulfide with phosphoric acid to generate hydrogen sulfide gas, and then the hydrogen sulfide gas and the arsenic-containing phosphoric acid are subjected to counter-current contact reaction to generate precipitation so as to achieve the aim of removing arsenic.
The technical scheme adopted by the invention is as follows: an arsenic removal method of industrial-grade wet-process phosphoric acid comprises the following steps:
(1) mixing sodium sulfide and raw material phosphoric acid in a hydrogen sulfide generator at the bottom of a filler dearsenification tower, wherein the adding amount of the sodium sulfide is 1.2 times of the equivalent of the arsenic content in the phosphoric acid, and the adding molar ratio of the sodium sulfide to the phosphoric acid is 1: 1.25, conveying the mixture to a hydrogen sulfide generator through a pump, and keeping the temperature of a reactor at 60 +/-2 ℃ for 15 min;
(2) hydrogen sulfide gas generated by the reaction is introduced into the arsenic removal packed tower through an exhaust pipe at the top of the generator;
(3) hydrogen sulfide gas enters a tail gas pipeline from bottom to top through a packed tower under the action of a tail gas fan, arsenic-containing phosphoric acid with other impurities removed overflows from the upper part of the packed tower and is subjected to countercurrent contact reaction to generate arsenic sulfide precipitate, so that arsenic in the phosphoric acid is removed;
(4) discharging the generated sodium phosphate solution to a collecting tank through an overflow pipe;
(5) filtering the mixed mother liquor after arsenic removal to obtain qualified industrial grade phosphoric acid containing less than 1ppm of arsenic.
The method has the advantages that the sodium sulfide and the phosphoric acid are subjected to countercurrent contact reaction in the packed tower, the mass transfer effect is good, the reaction is relatively sufficient, the material consumption is low, the arsenic removal effect is stable, and the arsenic content in the final product is less than 1 ppm.
The invention has the following advantages and innovations:
(1) the hydrogen sulfide gas generated at the bottom of the tower and arsenic-containing phosphoric acid overflowing from the top are subjected to countercurrent contact reaction by using the working principle of a packed tower, so that the mass transfer efficiency is high, the utilization rate of the hydrogen sulfide is high, and the usage amount of sodium sulfide is only 20% of the original usage amount;
(2) the equipment is totally closed, and a stirring device is not arranged, so that the safety risk caused by the overflow of hydrogen sulfide is avoided;
(3) the generated hydrogen sulfide gas is contacted with phosphoric acid, so that sodium ions are completely prevented from entering industrial-grade phosphoric acid, and the method has wider application range for the industrial-grade phosphoric acid.
Drawings
FIG. 1 is a schematic diagram of the process of the present invention.
Detailed Description
Example 1
(1) Mixing sodium sulfide and raw material phosphoric acid in a hydrogen sulfide generator at the bottom of a filler dearsenification tower, wherein the adding amount of the sodium sulfide is 1.2 times of the equivalent of the arsenic content in the phosphoric acid, and the adding molar ratio of the sodium sulfide to the phosphoric acid is 1: 1.25, conveying the mixture to a hydrogen sulfide generator through a pump, and keeping the temperature of a reactor at 60 +/-2 ℃ for 15 min;
(2) introducing hydrogen sulfide gas generated by the reaction into the arsenic removal packed tower through an exhaust pipe at the top of the generator;
(3) hydrogen sulfide gas enters a tail gas pipeline from bottom to top through a packed tower under the action of a tail gas fan, arsenic-containing phosphoric acid with other impurities removed overflows from the upper part of the packed tower and is subjected to countercurrent contact reaction to generate arsenic sulfide precipitate, so that arsenic in the phosphoric acid is removed;
(4) discharging the generated sodium phosphate solution to a collecting tank through an overflow pipe;
(5) filtering the mixed mother liquor after arsenic removal to obtain qualified industrial-grade phosphoric acid with the arsenic content of 0.9 ppm.
Example 2
An arsenic removal method of industrial-grade wet-process phosphoric acid comprises the following steps:
(1) mixing sodium sulfide and raw material phosphoric acid in a hydrogen sulfide generator at the bottom of a filler dearsenification tower, wherein the adding amount of the sodium sulfide is 1.3 times of the equivalent of the arsenic content in the phosphoric acid, and the adding molar ratio of the sodium sulfide to the phosphoric acid is 1: 1.35, conveying the mixture to a hydrogen sulfide generator through a pump, and keeping the temperature of a reactor at 60 +/-2 ℃ for 15 min;
(2) introducing hydrogen sulfide gas generated by the reaction into the arsenic removal packed tower through an exhaust pipe at the top of the generator;
(3) hydrogen sulfide gas enters a tail gas pipeline from bottom to top through a packed tower under the action of a tail gas fan, arsenic-containing phosphoric acid which overflows from the upper part of the packed tower and is removed of other impurities is subjected to countercurrent contact reaction to generate arsenic sulfide precipitate, and thus arsenic in the phosphoric acid is removed;
(4) discharging the generated sodium phosphate solution to a collecting tank through an overflow pipe;
(5) filtering the mixed mother liquor after arsenic removal to obtain qualified industrial-grade phosphoric acid with the arsenic content of 0.5 ppm.
Claims (1)
1. The industrial-grade wet-process phosphoric acid arsenic removal method is characterized by comprising the following steps of:
(1) mixing sodium sulfide and raw material phosphoric acid in a hydrogen sulfide generator at the bottom of a filler dearsenification tower, wherein the addition amount of the sodium sulfide is 1.2 to 1.3 times of the equivalent of the arsenic content in the phosphoric acid, and the molar ratio of the sodium sulfide to the phosphoric acid is 1: 1.25, conveying the mixture to a hydrogen sulfide generator through a pump, and keeping the temperature of a reactor at 60 +/-2 ℃ for 15 min;
(2) introducing hydrogen sulfide gas generated by the reaction into the arsenic removal packed tower through an exhaust pipe at the top of the generator;
(3) hydrogen sulfide gas enters a tail gas pipeline from bottom to top through a packed tower under the action of a tail gas fan, arsenic-containing phosphoric acid with other impurities removed overflows from the upper part of the packed tower and is subjected to countercurrent contact reaction to generate arsenic sulfide precipitate, so that arsenic in the phosphoric acid is removed;
(4) discharging the generated sodium phosphate solution to a collecting tank through an overflow pipe;
(5) filtering the mixed mother liquor after arsenic removal to obtain qualified industrial grade phosphoric acid containing less than 1ppm of arsenic.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210632076.0A CN115057419A (en) | 2022-06-07 | 2022-06-07 | Industrial-grade wet-process phosphoric acid dearsenification method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210632076.0A CN115057419A (en) | 2022-06-07 | 2022-06-07 | Industrial-grade wet-process phosphoric acid dearsenification method |
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| CN202210632076.0A Pending CN115057419A (en) | 2022-06-07 | 2022-06-07 | Industrial-grade wet-process phosphoric acid dearsenification method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1363965A (en) * | 1971-03-03 | 1974-08-21 | Knapsack Ag | Process and apparatus for the continuous dearsenification of poly phosphoric acid |
| CN102431982A (en) * | 2011-09-26 | 2012-05-02 | 瓮福（集团）有限责任公司 | Arsenic removing method of phosphoric acid |
| CN103979510A (en) * | 2014-04-25 | 2014-08-13 | 防城港博森化工有限公司 | Dearsenization method in production of phosphoric acid |
| CN108910850A (en) * | 2018-09-25 | 2018-11-30 | 湖北兴福电子材料有限公司 | A kind of thermal method electron-level phosphoric acid arsenic removing method |
| CN112225188A (en) * | 2020-10-15 | 2021-01-15 | 中国五环工程有限公司 | Process for removing arsenic from phosphoric acid by wet method |
| CN112661128A (en) * | 2021-01-18 | 2021-04-16 | 瓮福（集团）有限责任公司 | Method for efficiently removing arsenic by wet-process purified phosphoric acid |
-
2022
- 2022-06-07 CN CN202210632076.0A patent/CN115057419A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1363965A (en) * | 1971-03-03 | 1974-08-21 | Knapsack Ag | Process and apparatus for the continuous dearsenification of poly phosphoric acid |
| CN102431982A (en) * | 2011-09-26 | 2012-05-02 | 瓮福（集团）有限责任公司 | Arsenic removing method of phosphoric acid |
| CN103979510A (en) * | 2014-04-25 | 2014-08-13 | 防城港博森化工有限公司 | Dearsenization method in production of phosphoric acid |
| CN108910850A (en) * | 2018-09-25 | 2018-11-30 | 湖北兴福电子材料有限公司 | A kind of thermal method electron-level phosphoric acid arsenic removing method |
| CN112225188A (en) * | 2020-10-15 | 2021-01-15 | 中国五环工程有限公司 | Process for removing arsenic from phosphoric acid by wet method |
| CN112661128A (en) * | 2021-01-18 | 2021-04-16 | 瓮福（集团）有限责任公司 | Method for efficiently removing arsenic by wet-process purified phosphoric acid |
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