阅读说明：本技术 一种海水制盐苦卤除氯化钠的方法 (Method for removing sodium chloride from bittern produced by seawater ) 是由 杨志梅 于 2020-05-18 设计创作，主要内容包括：本发明公开了一种海水制盐苦卤除氯化钠的方法,属于海盐生产技术领域。所述海水制盐苦卤除氯化钠的方法,包括如下步骤：分别取海水制盐苦卤和老卤,按照体积比为1.4:1-3:1,进行搅拌混合,蒸发后冷却,将结晶析出的固体分离,取母液,即为除氯化钠后的卤水。本发明的海水制盐苦卤除氯化钠的方法,除氯化钠效率高,除氯化钠后的卤水中含氯化钠量低,同时,苦卤中的硫酸镁析出很少,对后续处理非常有利,具有良好的经济前景和社会效益。(The invention discloses a method for removing sodium chloride from bittern produced by seawater, belonging to the technical field of sea salt production. The method for removing sodium chloride from bittern in seawater salt production comprises the following steps: respectively taking seawater to prepare salt bittern and old bittern, stirring and mixing according to the volume ratio of 1.4:1-3:1, cooling after evaporation, separating solid separated out by crystallization, and taking mother liquor, namely the bittern without sodium chloride. The method for removing the sodium chloride from the bittern obtained by preparing the salt from the seawater has high sodium chloride removal efficiency, the sodium chloride content in the bittern after the sodium chloride removal is low, and simultaneously, the magnesium sulfate in the bittern is separated out little, so that the method is very beneficial to subsequent treatment and has good economic prospect and social benefit.)

1. A method for removing sodium chloride from bittern produced by seawater is characterized by comprising the following steps: respectively taking seawater to prepare salt bittern and old bittern, stirring and mixing according to the volume ratio of 1.4:1-3:1, cooling after evaporation, separating solid separated out by crystallization, and taking mother liquor, namely the bittern without sodium chloride.

2. The method for removing sodium chloride from seawater salt-making bittern of claim 1, wherein said seawater salt-making bittern contains 90g/L-150g/L NaCl, 150g/L-200g/L MgCl₂25g/L-40g/L KCl and 50g/L-100g/L MgSO₄。

3. The method for removing sodium chloride from bittern obtained from seawater as claimed in claim 1, wherein said aged bittern contains 3g/L-40g/L NaCl, 350g/L-450g/L MgCl₂2g/L-8g/L KCl and 10g/L-50g/L MgSO₄。

4. The method for removing sodium chloride from bittern produced from seawater as claimed in claim 1, wherein the mixing is continuous mixing or batch mixing.

5. The method for removing sodium chloride from bittern produced from seawater as claimed in claim 1, wherein the evaporation is any one of single effect evaporator, double effect evaporator and triple effect evaporator.

6. The method for removing sodium chloride from bittern produced from seawater as claimed in claim 1, wherein the final temperature of evaporation is 120-130 ℃.

7. The method for removing sodium chloride from bittern produced from seawater as claimed in claim 1, wherein the final temperature of cooling is 40-80 ℃.

8. The method for removing sodium chloride from seawater salt production bittern of any one of claims 1-7, wherein the bittern after sodium chloride removal contains 3g/L-15g/L NaCl, 300g/L-400g/L MgCl₂10g/L-25g/L KCl and 45g/L-80g/L MgSO₄。

Technical Field

The invention relates to a method for removing sodium chloride in salt bittern prepared from seawater, belonging to the technical field of chemical production of the salt bittern.

Background

In the production process of sea salt, about 1m of byproduct is produced when 1t of raw salt is produced³Salt production waste liquid (commonly called bittern). The bittern contains high-concentration potassium chloride, magnesium sulfate, sodium chloride and other components, and is used mainly in producing potassium chloride and co-producing magnesium chloride, magnesium sulfate, industrial salt and other products. Various chemical elements in the bittern are concentrated by about 40 times compared with seawater, and the bittern is an excellent raw material for extracting the chemical elements in the seawater, but the seawater bittern chemical enterprises are generally in a loss state due to the limitation of technical level. The realization of the thorough comprehensive utilization of the bittern is an effective measure for solving the shortage of land resources, is a necessary guarantee for realizing the energy conservation and emission reduction of the sea salt production, and is forced in the chemical industry of the sea salt bitternThe problem to be solved urgently is solved.

At present, bitter bittern is usually evaporated, part of old bittern (concentrated bittern) is added in the evaporation process, the temperature is reduced after the evaporation is finished, the heat preservation and the sedimentation are carried out, the solid obtained by the sedimentation is discharged, the temperature is continuously reduced to 35-50 ℃, the solid crystallized again is separated, and the solid phase obtained by the separation is carnallite which mainly contains potassium chloride and magnesium chloride and a small amount of sodium chloride; the liquid phase is old brine (also called thick brine), mainly contains magnesium chloride and contains a small amount of potassium chloride, sodium chloride and magnesium sulfate. Magnesium sulfate in the method can be separated out along with sodium chloride, and most of sodium chloride cannot be removed completely at one time, which brings great difficulty to subsequent treatment and influences the product quality.

Therefore, how to firstly remove the sodium chloride in the bittern for preparing salt from seawater and simultaneously separate out the magnesium sulfate as little as possible is the key for improving the product quality and reducing the energy consumption.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for removing sodium chloride from bittern produced by seawater. The method for removing the sodium chloride from the bittern produced by the seawater has the advantages that only a few magnesium sulfate in the bittern is simultaneously separated out along with the sodium chloride, the sodium chloride removing efficiency is high, the sodium chloride content in the bittern after the sodium chloride is removed is low, the method is very beneficial to subsequent treatment, and the method has good economic prospect and social benefit.

The technical scheme for solving the technical problems is as follows: a method for removing sodium chloride from bittern produced by seawater comprises the following steps:

respectively taking seawater to prepare salt bittern and old bittern, stirring and mixing according to the volume ratio of 1.4:1-3:1, cooling after evaporation, separating solid separated out by crystallization, and taking mother liquor, namely the bittern without sodium chloride.

The method for removing sodium chloride by using brine produced by seawater has the beneficial effects that:

1. the method for removing the sodium chloride from the bittern obtained by preparing the salt from the seawater has high sodium chloride removal efficiency (more than or equal to 83.3 percent), the sodium chloride content in the bittern after the sodium chloride removal is low (3g/L-15g/L), and only a little magnesium sulfate is separated out along with the sodium chloride, so the method is very beneficial to subsequent treatment and has good economic prospect and social benefit.

2. The method for removing sodium chloride from bittern in seawater salt production has the advantages of simple process, low energy consumption, low cost, wide market prospect and suitability for large-scale popularization and application.

On the basis of the technical scheme, the invention can be further improved as follows.

Furthermore, the bittern for preparing salt from seawater contains 90g/L-150g/L NaCl and 150g/L-200g/L MgCl₂25g/L-40g/L KCl and 50g/L-100g/L MgSO₄。

Furthermore, the old brine contains 3g/L-40g/L NaCl and 350g/L-450g/L MgCl₂2g/L-8g/L KCl and 10g/L-50g/L MgSO₄。

The adoption of the further beneficial effects is as follows: the old bittern contains magnesium chloride with higher concentration, and is beneficial to removing sodium chloride after being added into the bittern.

Further, the mixing mode is continuous mixing or batch mixing.

The adoption of the further beneficial effects is as follows: by adopting the two mixing modes, the uniform mixing of the brine and the old brine produced by the seawater can be realized.

Further, the evaporation adopts any one of a single-effect evaporator, a double-effect evaporator and a triple-effect evaporator.

The adoption of the further beneficial effects is as follows: by adopting the evaporator, the evaporation of the mixture of the brine and the old brine produced by seawater can be realized.

The single-effect evaporator can be purchased commercially, such as from Changzhou prant environmental protection equipment, Inc., with a specification of WZ 3000; the double-effect evaporator can be purchased commercially, for example, from solitaire (shanghai) environmental technology ltd, with the specification GLWXH-03; the triple-effect evaporator can be purchased commercially, for example, from Longhu Dry engineering, Inc., of Changzhou, and has a specification of SJN-5000.

Further, the final temperature of the evaporation is 120-130 ℃.

The adoption of the further beneficial effects is as follows: with the above temperatures, evaporation can be achieved.

Further, the final temperature of the cooling is 40-80 ℃.

The adoption of the further beneficial effects is as follows: with the above temperatures, cooling can be achieved.

Furthermore, the brine after the sodium chloride removal contains 3g/L-15g/L of NaCl and 300g/L-400g/L of MgCl₂10g/L-25g/L KCl and 45g/L-80g/L MgSO₄。

The adoption of the further beneficial effects is as follows: after the treatment of the invention, in the brine prepared from seawater, the NaCl concentration is reduced from 90g/L-150g/L to 3g/L-15g/L, the removal rate is more than or equal to 83.3 percent, and simultaneously, little magnesium sulfate is separated out, thus being very beneficial to the subsequent treatment.

Detailed Description

The principles and features of this invention are described below in conjunction with specific embodiments, which are set forth merely to illustrate the invention and are not intended to limit the scope of the invention.