CN-122010144-A - Production process for preparing sodium chloride and sodium sulfate from bittern and nitrobittern double raw materials

CN122010144ACN 122010144 ACN122010144 ACN 122010144ACN-122010144-A

Abstract

The invention discloses a production process for preparing sodium chloride and sodium sulfate from bittern and bittern double raw materials, and relates to the technical field of salt chemical industry. The process takes bittern and bittern as raw materials simultaneously, realizes continuous separation in the same set of multiple-effect evaporation system, and respectively obtains sodium chloride and sodium sulfate products. The method comprises the steps of preheating bittern, entering a high-temperature and low-temperature evaporation salt production effect, separating sodium chloride to obtain high-temperature and low-temperature salt production mother liquor, preheating bittern, entering a low-temperature evaporation salt production effect, separating sodium sulfate to obtain high-salt or low-salt production mother liquor, merging part of mother liquor and a final-effect circulation mother liquor, entering a medium-temperature salt production effect, separating out sodium sulfate again, further recovering sodium chloride from the obtained nitrate production mother liquor through flash evaporation or low-temperature evaporation, and returning the final-effect salt production mother liquor to the medium-temperature salt production effect for recycling after waste heat is recovered.

Inventors

HU JINRONG
CAO SHOUBIN
LI GUOSHENG
SUN JIN
ZHU SHIYANG

Assignees

江苏瑞洪盐业有限公司

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (10)

1. A production process for preparing sodium chloride and sodium sulfate from bittern and bittern by double raw materials is characterized by comprising the following steps: step one, brine pretreatment and sodium chloride primary separation Preheating bittern, then pretreating, and entering an evaporation system to obtain sodium chloride and high-temperature salt-making mother liquor; step two, pretreatment of nitrohalogen and primary separation of sodium sulfate Preheating the nitrobittern, allowing the nitrobittern to enter a low-temperature evaporation nitroIII-effect evaporation tank, separating out a sodium sulfate product, and obtaining a low-salt nitromother liquor; Step three, mother liquor mixing and sodium sulfate main separation The high-temperature salt-making mother liquor obtained in the first step, the low-salt-making mother liquor obtained in the second step and the final-effect salt-making mother liquor recycled by the system are jointly sent into a medium-temperature evaporation nitrate-making II-effect evaporation tank, under the condition, sodium sulfate is crystallized and separated again in a large amount to obtain sodium sulfate products, and meanwhile, the nitrate-making mother liquor is produced; step four, treating the mother liquor for preparing the nitre and recycling sodium chloride Treating the nitrate-making mother liquor obtained in the step three, further recovering sodium chloride in the nitrate-making mother liquor, and obtaining low-temperature salt-making mother liquor; step five, final salt production and final mother liquor production Sending the low-temperature salt-making mother liquor obtained in the step four into a low-temperature evaporation salt-making final-effect evaporation tank, evaporating and crystallizing, and recycling sodium chloride again to obtain final-effect salt-making mother liquor; Step six, waste heat recovery and mother liquor circulation Preheating the final-effect salt-making mother liquor, recycling the preheated mother liquor to the medium-temperature evaporation nitrate-making II-effect evaporation tank in the third step, taking part in the reaction as a part of raw materials to realize continuous production, and finally recycling to obtain the products sodium chloride and sodium sulfate.
2. The production process for preparing sodium chloride and sodium sulfate by using the bittern and bittern double raw materials is characterized by comprising the following steps of preheating bittern, enabling all advection to enter an IV-effect evaporation tank and a III-effect evaporation tank for preparing salt through low-temperature evaporation, separating out part of sodium chloride, obtaining low-nitrate salt mother liquor, enabling the mother liquor to enter an I-effect evaporation tank for preparing salt through high-temperature evaporation in a countercurrent mode, further separating out sodium chloride, and producing high-temperature salt mother liquor, wherein the temperature range of the I-effect evaporation tank for preparing salt through high-temperature evaporation is 100-150 ℃.
3. The production process for preparing sodium chloride and sodium sulfate by using the bittern and nitrobittern as raw materials is characterized by comprising the following steps of dividing the preheated bittern into two parts, enabling the first part of bittern to enter an IV-effect evaporation tank and a III-effect evaporation tank for preparing salt through low-temperature evaporation after being preheated to obtain mother liquor for preparing sodium chloride and high-nitrate, and enabling the second part of bittern to enter the I-effect evaporation tank for preparing salt through high-temperature evaporation after being preheated to obtain mother liquor for preparing sodium chloride and high-temperature salt.
4. The process for preparing sodium chloride and sodium sulfate by using the bittern and nitrobittern as defined in claim 1, wherein in the fourth step, the treatment method is any one of flash evaporation and low-temperature evaporation.
5. The production process for preparing sodium chloride and sodium sulfate from the bittern and nitrohalogen double raw materials is characterized in that the temperature range of a low-temperature evaporation salt-making final-effect evaporation tank is 35-55 ℃, and the temperature range of a medium-temperature evaporation nitrohalogen II-effect evaporation tank is 80-110 ℃.
6. The production process for preparing sodium chloride and sodium sulfate by using the bittern and nitrobittern double raw materials according to claim 4, wherein the low-temperature evaporation process is that the nitrosation mother liquor passes through a low-temperature evaporation salt-making III-effect evaporation tank and a low-temperature evaporation salt-making IV-effect evaporation tank to obtain the sodium chloride and the low-temperature salt-making mother liquor.
7. The production process for preparing sodium chloride and sodium sulfate by using the bittern and nitrobittern dual raw materials according to any one of claims 2 or 3 is characterized in that the temperature range of the low-temperature evaporation salt-making IV-effect evaporation tank is 55-90 ℃, and the temperature range of the low-temperature evaporation salt-making III-effect evaporation tank is 45-70 ℃.
8. The process for preparing sodium chloride and sodium sulfate by using the bittern and nitrobittern as raw materials according to claim 4, wherein the flash evaporation comprises 1-level flash evaporation and 2-level flash evaporation, and the process comprises the steps of sequentially carrying out 1-level flash evaporation and 2-level flash evaporation on the nitrosation mother liquor to obtain sodium chloride and low-temperature salt-making mother liquor, wherein the temperature range of the 1-level flash evaporation is 80-95 ℃, and the temperature range of the 2-level flash evaporation is 60-75 ℃.
9. The production process for preparing sodium chloride and sodium sulfate from the bittern and nitrobittern as claimed in claim 1, wherein the bittern comprises 280-310 g/L NaCl and 5.0-30 g/L Na 2 SO 4 5.0.0 in terms of mass volume concentration.
10. The production process for preparing sodium chloride and sodium sulfate from the bittern and nitrohalogen double raw materials according to claim 1 is characterized in that the nitrohalogen comprises 255-60 g/L of NaCl and 2 SO 4 -290 g/L of Na according to mass volume concentration.

Description

Production process for preparing sodium chloride and sodium sulfate from bittern and nitrobittern double raw materials Technical Field The invention relates to the technical field of salt chemical industry, in particular to a production process for preparing sodium chloride and sodium sulfate from bittern and nitrobittern. Background Rock salt deposits are often associated with nitrohalogen resources. The traditional exploitation and processing modes often consider bittern and nitrobittern as independent systems, and adopt a separate exploitation and treatment separation process. The bittern contains sodium chloride as main component and small amount of sodium sulfate, while the nitro-bittern contains sodium sulfate and sodium chloride. Because the physical and chemical properties of the two are similar, if a conventional single raw material evaporation process is adopted, the problems of low purity of a target product, mixed byproducts, high energy consumption, difficult mother liquor circulation and the like are easily caused. Particularly in typical mining areas such as Jiangsu Huaian and the like, a large number of high-salt nitrohaloid old wells with complex components are formed under the influence of historical exploitation and geological structures. Meanwhile, in the salt cavern gas storage project greatly developed in recent years, low-nitrate bittern with different components is continuously generated in the cavity making and operation processes. If the two types of brine can not be cooperatively and efficiently utilized, not only is the high-quality mineral resources seriously wasted, but also double pressure is formed on environmental management and enterprise economic benefit. At present, although related enterprises in the area build a nitrate separating device with a certain scale, the process route is designed aiming at single type brine, and it is difficult to efficiently treat two raw materials of bittern and nitrate at the same time. If two independent production lines are newly built, the investment is huge, the occupied area is increased, the energy consumption is superposed, the internal coupling optimization of energy and materials cannot be realized, and the development requirements of green low carbon and circular economy are not met. In order to solve the problems, the invention provides a production process for preparing sodium chloride and sodium sulfate from bittern and nitrobittern. Disclosure of Invention The invention aims to provide a production process for preparing sodium chloride and sodium sulfate from bittern and nitrobittern by using double raw materials, so as to solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: a production process for preparing sodium chloride and sodium sulfate from bittern and bittern double raw materials comprises the following steps: step one, brine pretreatment and sodium chloride primary separation Preheating bittern, then pretreating, and entering an evaporation system to obtain sodium chloride and high-temperature salt-making mother liquor; step two, pretreatment of nitrohalogen and primary separation of sodium sulfate Preheating the nitrobittern, allowing the nitrobittern to enter a low-temperature evaporation nitroIII-effect evaporation tank, separating out a sodium sulfate product, and obtaining a low-salt nitromother liquor; Step three, mother liquor mixing and sodium sulfate main separation The high-temperature salt-making mother liquor obtained in the first step, the low-salt-making mother liquor obtained in the second step and the final-effect salt-making mother liquor recycled by the system are jointly sent into a medium-temperature evaporation nitrate-making II-effect evaporation tank, under the condition, sodium sulfate is crystallized and separated again in a large amount to obtain sodium sulfate products, and meanwhile, the nitrate-making mother liquor is produced; step four, treating the mother liquor for preparing the nitre and recycling sodium chloride Treating the nitrate-making mother liquor obtained in the step three, further recovering sodium chloride in the nitrate-making mother liquor, and obtaining low-temperature salt-making mother liquor; step five, final salt production and final mother liquor production Sending the low-temperature salt-making mother liquor obtained in the step four into a low-temperature evaporation salt-making final-effect evaporation tank, evaporating and crystallizing, and recycling sodium chloride again to obtain final-effect salt-making mother liquor; Step six, waste heat recovery and mother liquor circulation Preheating the final-effect salt-making mother liquor, recycling the preheated mother liquor to the medium-temperature evaporation nitrate-making II-effect evaporation tank in the third step, taking part in the reaction as a part of raw materials to realize continuous production, and finally recycl