Process for preparing anhydrous mirabilite by freezing method

An anhydrous nitrate and freezing technology, applied in the chemical industry, sustainable manufacturing/processing, alkali metal sulfite/sulfate dehydration, etc., can solve the problems of high energy consumption and unstable product quality

Active Publication Date: 2006-09-27
ENG TECH INST CO LTD OF CNSIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former product quality is guaranteed, but consumes a lot of energy; although the latter is energy-saving, it uses salt for nitrate, and the quality of the finished product is unstable

Method used

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  • Process for preparing anhydrous mirabilite by freezing method
  • Process for preparing anhydrous mirabilite by freezing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The nitrate-containing solution with a mass concentration of 70g / l is preliminarily cooled to 10°C by using the cold mother liquor as a refrigerant through a precooler. Then transfer the feed liquid to the pre-cooling crystallizer. The refrigerant of the pre-cooling crystallizer uses the cold mother liquor with a temperature of -4°C to freeze the feed liquid for a period of time. After that, it enters the frozen crystallizer for the second stage of freezing and analyzing nitrate. The refrigerant of the frozen crystallizer is the frozen calcium chloride brine with a temperature of -10°C provided by the refrigeration process to freeze the feed liquid to -6°C, and the calcium chloride brine is discharged from the refrigeration system. The frozen feed liquid enters the settler for solid-liquid separation. The cold mother liquor overflowing from the settler is used as the refrigerant for the pre-cooling crystallizer and the pre-cooler successively in two steps. It then ex...

Embodiment 2

[0021] The nitrate-containing solution with a mass concentration of 65g / l is preliminarily cooled to 15°C by using the cold mother liquor as a refrigerant through a precooler. Then transfer the feed liquid to the pre-cooling crystallizer. The refrigerant of the pre-cooling crystallizer uses the cold mother liquor with a temperature of -5°C to freeze the feed liquid for a period of time. After that, it enters the frozen crystallizer for the second stage of freezing and analyzing nitrate. The refrigerant of the frozen crystallizer is the frozen calcium chloride brine with a temperature of -8°C provided by the refrigeration process to freeze the feed liquid to -5°C, and the frozen calcium chloride brine is discharged out of the refrigeration system. The frozen feed liquid enters the settler for solid-liquid separation. The cold mother liquor overflowing from the settler is used as the refrigerant for the pre-cooling crystallizer and the pre-cooler successively in two steps. It...

Embodiment 3

[0023] The nitrate-containing solution with a mass concentration of 65g / l is preliminarily cooled to 20°C by using the cold mother liquor as a refrigerant through a precooler. Then transfer the feed liquid to the pre-cooling crystallizer. The refrigerant of the pre-cooling crystallizer uses the cold mother liquor with a temperature of -5°C to freeze the feed liquid for a period of time. After that, it enters the frozen crystallizer for the second stage of freezing and analyzing nitrate. The refrigerant of the frozen crystallizer is the temperature provided by the refrigeration process. The calcium chloride brine is frozen at -12°C to freeze the feed liquid to -7°C, and the calcium chloride brine is discharged from the refrigeration system. The frozen feed liquid enters the settler for solid-liquid separation. The cold mother liquor overflowing from the settler is used as the refrigerant for the pre-cooling crystallizer and the pre-cooler successively in two steps. It then e...

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Abstract

The invention discloses a new technics about the production of freezing method absolute nitrate, containing steps as follows: getting the solution contains saltpeter across precooler to doing coolant elementary cooling by cold mother liquor; switching the feed liquid from precooler to precooler crystallizer; adding the feed liquid from precooler crystallizer in cooler crystallizer to freeze the feed liquid to -5-7Deg C for the saltpeter separating of second phase refrigeration; Adding the feed liquid from cooler crystallizer in depressor for solid-liquid separation; passing the discharged sodium sulfate from precooler through screw pump to feed the dewatering machine; putting the dewatered sodium sulfate in saltpeter melting tank, mixing with the swinged liquid of evaporate discharged feed liquid or absolute nitrate plasm, making sodium sulfate autolyze by end effect quadratic steam heating. In the saltpeter melting procedure of this method, adopting hot material and sodium sulfate mixing melt saltpeter, at the same time, using low-grade second steam heat energy heat up the feed liquid, compared to the former pervaporation, this method is more reasonable, energy saving and ensure the quality of product.

Description

technical field [0001] The invention relates to a production process of anhydrous nitrate, in particular to a new process for producing anhydrous nitrate by freezing method. Background technique [0002] At present, the anhydrous nitrate production process only has the ammonia freezing nitrate system, but there is no application technology that uses frozen brine as a refrigerant. As we all know, the preparation of anhydrous nitrate from Glauber's salt mainly includes the total solution evaporation method and the salting out method. The former product quality is guaranteed, but consumes a lot of energy; although the latter is energy-saving, it trades salt for nitrate, and the quality of the finished product is unstable. Contents of the invention [0003] The object of the present invention is to provide a new process for producing anhydrous nitric acid by freezing method, which not only ensures the quality of the product, but also achieves the purpose of energy saving. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D5/18
CPCY02P20/10
Inventor 戈金阳董连福李洪张水明
Owner ENG TECH INST CO LTD OF CNSIC
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