CN-122029129-A - Preparation method and preparation device of sodium bicarbonate and gypsum

CN122029129ACN 122029129 ACN122029129 ACN 122029129ACN-122029129-A

Abstract

The present invention relates to a method and apparatus for preparing sodium bicarbonate and gypsum, the method comprising a step of adding carbon dioxide (CO 2 ) and ammonia (NH 3 ) to a sodium sulfate solution to prepare sodium bicarbonate, a step of adding a calcium (Ca) containing substance to a first filtrate generated in the step of preparing sodium bicarbonate to prepare and recover first gypsum (CaSO 4 ), a step of adding sodium carbonate (Na 2 CO 3 ) to a second filtrate generated in the step of preparing and recovering first gypsum to precipitate calcium carbonate (CaCO 3 ) to remove Ca substances and then recovering ammonia, and a step of adding sulfuric acid to a waste liquid generated in the step of recovering ammonia after mixing the first gypsum to prepare second gypsum having a higher purity than the first gypsum. According to the invention, the scaling problem caused by calcium can be solved, and the preparation cost of sodium bicarbonate and gypsum can be reduced.

Inventors

Min Chengji
BIAN YONGZHE
LI YINGFENG
Jin Huanji
JIN BINGJI

Assignees

浦项控股股份有限公司
浦项产业科学硏究院

Dates

Publication Date: 20260512
Application Date: 20241203
Priority Date: 20231215

Claims (8)

1. A method for preparing sodium bicarbonate and gypsum, comprising: A step of adding carbon dioxide (CO 2 ) and ammonia (NH 3 ) to a sodium sulfate solution to prepare sodium bicarbonate; A step of adding a calcium (Ca) containing substance to the first filtrate generated in the step of preparing sodium bicarbonate to prepare and recover first gypsum (CaSO 4 ); A step of adding sodium carbonate (Na 2 CO 3 ) to the second filtrate produced in the step of preparing and recovering the first gypsum to precipitate calcium carbonate (CaCO 3 ) to remove calcium ions (Ca 2+ ) and recovering ammonia, and And a step of adding sulfuric acid after mixing the first gypsum in the waste liquid generated in the ammonia recovery step to produce a second gypsum having a higher purity than the first gypsum.
2. The method for preparing sodium bicarbonate and gypsum according to claim 1, wherein the sodium sulfate solution is prepared by a step of forming a sodium sulfate solution from a raw material containing sodium sulfate (Na 2 SO 4 ).
3. The method for preparing sodium bicarbonate and gypsum according to claim 1, wherein the recovered ammonia is re-added to the sodium sulfate solution during the step of preparing sodium bicarbonate.
4. The method for producing sodium bicarbonate and gypsum according to claim 1, wherein the second filtrate contains 40ppm to 1000ppm of calcium based on the total concentration of the second filtrate.
5. The method for preparing sodium bicarbonate and gypsum according to claim 1, wherein the sodium carbonate is added to the second filtrate in an amount of 0.1 to 10% by weight based on the total weight of the second filtrate.
6. The method for preparing sodium bicarbonate and gypsum according to claim 1, wherein the calcium-containing substance is quicklime (CaO).
7. The method for preparing sodium bicarbonate and gypsum according to claim 1, wherein after the step of preparing the second gypsum, further comprising a step of adding sodium carbonate (Na 2 CO 3 ) to the fourth filtrate generated in the step of preparing the second gypsum to precipitate calcium carbonate (CaCO 3 ) to remove Ca substances.
8. A preparation device of sodium bicarbonate and gypsum, comprising: a sodium bicarbonate preparation machine that receives a sodium sulfate solution, carbon dioxide (CO 2 ), and ammonia (NH 3 ) to prepare sodium bicarbonate; A first gypsum preparation machine that receives the first filtrate and calcium (Ca) containing material generated in the sodium bicarbonate preparation machine to prepare first gypsum (CaSO 4 ); An ammonia recoverer that receives the second filtrate and sodium carbonate (Na 2 CO 3 ) produced in the first gypsum preparation machine to precipitate calcium carbonate (CaCO 3 ) to remove calcium ions (Ca 2+ ) and then recovers ammonia, and And a second gypsum preparation machine which receives the waste liquid generated in the ammonia recovery machine and the first gypsum and receives sulfuric acid after mixing to prepare second gypsum having a higher purity than the first gypsum.

Description

Preparation method and preparation device of sodium bicarbonate and gypsum Technical Field The invention relates to a preparation method and a device of sodium bicarbonate and gypsum. Background Sulfur oxides (SOx) are not only the main cause of acid rain, but also harmful gases that can cause respiratory diseases after being absorbed by the human body. Currently, with the development of industry, the amount of sulfur oxides discharged from various factories, thermal power plants, and incineration sites is increasing, and in order to minimize the amount of sulfur oxides discharged, various desulfurization methods are being applied on site. Currently, in the sintering plants of iron works, sodium bicarbonate (NaHCO 3) is being used as an adsorbent in order to remove sulfur oxides, and in order to meet increasingly strict environmental regulations, the use amount of sodium bicarbonate is also increasing. When industrial sodium bicarbonate is imported from overseas, there is a problem in that the import price of sodium bicarbonate varies greatly according to the economic conditions of overseas. In addition, carbon dioxide and mirabilite (sodium sulfate, na 2SO4) are produced in the reaction of removing sulfur oxides with sodium bicarbonate, and these materials are currently directly buried, causing problems of disposal cost and secondary environment. If the process for preparing sodium bicarbonate and gypsum by utilizing mirabilite is adopted, various problems of waste reduction, carbon neutralization, stable raw material supply through internal circulation of sodium bicarbonate and the like can be solved, so the development of the technology is urgent. Disclosure of Invention First, the technical problem to be solved The preparation method of sodium bicarbonate and gypsum of the invention aims to precipitate calcium carbonate (CaCO 3) by adding sodium carbonate (Na 2CO3) to remove calcium contained in filtrate, thereby solving the problem of equipment scaling (scale) caused by calcium and reducing the concentration of calcium ions (Ca 2+) in the filtrate to an operable level. (II) technical scheme The method for preparing sodium bicarbonate and gypsum according to one embodiment of the present invention includes a step of adding carbon dioxide (CO 2) and ammonia (NH 3) to a sodium sulfate solution to prepare sodium bicarbonate, a step of adding a calcium (Ca) containing substance to a first filtrate generated in the step of preparing sodium bicarbonate to prepare and recover first gypsum (CaSO 4), a step of adding sodium carbonate (Na 2CO3) to a second filtrate generated in the step of preparing and recovering first gypsum to precipitate calcium carbonate (CaCO 3) to remove calcium ions (Ca 2+) and then recover ammonia, and a step of adding sulfuric acid to a waste liquid generated in the step of recovering ammonia after mixing the first gypsum to prepare second gypsum having a higher purity than the first gypsum. The sodium sulfate solution may be prepared by a step of forming a sodium sulfate solution from a raw material containing sodium sulfate (Na 2SO4). The recovered ammonia may be re-added to the sodium sulphate solution during the step of preparing sodium bicarbonate. The second filtrate may comprise from 40ppm to 1000ppm calcium based on the total concentration of the second filtrate. The sodium carbonate may be added to the second filtrate in an amount of 0.1 to 10 wt% based on the total weight of the second filtrate. The calcium-containing material may be quicklime (CaO). The method for preparing sodium bicarbonate and gypsum according to another embodiment of the present invention may further include a step of adding sodium carbonate (Na 2CO3) to the fourth filtrate generated in the step of preparing the second gypsum to precipitate calcium carbonate (CaCO 3) to remove Ca material after the step of preparing the second gypsum. The apparatus for preparing sodium bicarbonate and gypsum according to another embodiment of the present invention includes a sodium bicarbonate preparing machine that receives a sodium sulfate solution, carbon dioxide (CO 2) and ammonia (NH 3) to prepare sodium bicarbonate, a first gypsum preparing machine that receives a first filtrate and calcium (Ca) containing material generated in the sodium bicarbonate preparing machine to prepare first gypsum (CaSO 4), an ammonia recovering machine that receives a second filtrate and sodium carbonate (Na 2CO3) generated in the first gypsum preparing machine to precipitate calcium carbonate (CaCO 3) to remove calcium ions (Ca 2+) and then recover ammonia, and a second gypsum preparing machine that receives a waste liquid generated in the ammonia recovering machine and the first gypsum and receives sulfuric acid after mixing to prepare second gypsum having a higher purity than the first gypsum. (III) beneficial effects According to the preparation method of sodium bicarbonate and gypsum, the scaling problem caused by calcium can be sol