Metod for preparing sodium carbonate heptahydrate and ammonium sulfate from wastes produced in process for producing sodium cyanate by urea method

A technology of sodium cyanate and sodium carbonate, applied in chemical instruments and methods, ammonium sulfate, alkali metal carbonate, etc., can solve problems such as loss, and achieve the effect of increasing economic benefits and reducing environmental pollution

Active Publication Date: 2012-09-05
南通华山实业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The second defect of this method is that the utilization rate of the raw material salt is only 72% to 74%, and the rest of the salt is discarded as waste liquid along with the calcium chloride solution, which is a great loss

Method used

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  • Metod for preparing sodium carbonate heptahydrate and ammonium sulfate from wastes produced in process for producing sodium cyanate by urea method
  • Metod for preparing sodium carbonate heptahydrate and ammonium sulfate from wastes produced in process for producing sodium cyanate by urea method

Examples

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Comparison scheme
Effect test

Embodiment 1

[0034] A method for preparing sodium carbonate heptahydrate and ammonium sulfate from the waste obtained by producing sodium cyanate with the urea method comprises the steps:

[0035] A: Send 500kg of industrial sodium sulfate to the carbonization tower (1), and feed ammonia and carbon dioxide into the carbonization tower (1) according to the mass ratio of sodium sulfate, ammonia, and carbon dioxide of 1:0.04:0.11 for carbonization reaction;

[0036] B: the reaction product obtained in step A is filtered through a suction filter pump (2) to obtain a clear filtrate and a filter cake of black impurities;

[0037]C: the clarified filtrate of step B gained is sent in the decompression distiller (3), carries out fractional distillation according to the freezing point of sodium carbonate and ammonium sulfate and cools in cooling tower (4), thereby obtains sodium carbonate decahydrate crystal respectively and ammonium sulfate crystals;

[0038] D: the ammonium sulfate crystal obtai...

Embodiment 2

[0041] A method for preparing sodium carbonate heptahydrate and ammonium sulfate from the waste obtained by producing sodium cyanate with the urea method comprises the steps:

[0042] A: Send 200kg of industrial sodium sulfate to the carbonization tower (1), and feed ammonia and carbon dioxide into the carbonization tower (1) according to the mass ratio of sodium sulfate, ammonia, and carbon dioxide of 1:0.24:0.31 for carbonization reaction;

[0043] B: the reaction product obtained in step A is filtered through a suction filter pump (2) to obtain a clear filtrate and a filter cake of black impurities;

[0044] C: the clarified filtrate of step B gained is sent in the decompression distiller (3), carries out fractional distillation according to the freezing point of sodium carbonate and ammonium sulfate and cools in cooling tower (4), thereby obtains sodium carbonate decahydrate crystal respectively and ammonium sulfate crystals;

[0045] D: the ammonium sulfate crystal obta...

Embodiment 3

[0048] A method for preparing sodium carbonate heptahydrate and ammonium sulfate from the waste obtained by producing sodium cyanate with the urea method comprises the steps:

[0049] A: Send 300kg of industrial sodium sulfate to the carbonization tower (1), and feed ammonia and carbon dioxide into the carbonization tower (1) according to the mass ratio of sodium sulfate, ammonia, and carbon dioxide of 1:0.44:0.51 for carbonization reaction;

[0050] B: the reaction product obtained in step A is filtered through a suction filter pump (2) to obtain a clear filtrate and a filter cake of black impurities;

[0051] C: the clarified filtrate of step B gained is sent in the decompression distiller (3), carries out fractional distillation according to the freezing point of sodium carbonate and ammonium sulfate and cools in cooling tower (4), thereby obtains sodium carbonate decahydrate crystal respectively and ammonium sulfate crystals;

[0052] D: the ammonium sulfate crystal obta...

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Abstract

The invention discloses a method for preparing sodium carbonate heptahydrate and ammonium sulfate from wastes produced in a process for producing sodium cyanate by a urea method. In the method, a process for preparing ammonium sulfate by the urea method and a process for preparing sodium carbonate by an ammonia alkali method are combined, the wastes produced in the process for preparing the sodium cyanate, which are taken as raw materials for the process for preparing sodium carbonate by the ammonia alkali method, and sodium sulfate serving as a cheap industrial material are used for producing the sodium carbonate heptahydrate and co-producing the ammonium sulfate. The method gives full play to the potential value of the wastes produced in the process for preparing sodium cyanate by the urea method, reduces environmental pollution and increases economic benefit of an enterprise.

Description

technical field [0001] The invention relates to the field of treatment and utilization of industrial waste gas, in particular to a method for preparing sodium carbonate heptahydrate and ammonium sulfate from waste obtained by producing sodium cyanate through a urea method. Background technique [0002] Sodium cyanate (sodium cyanate, or cyanic acid sodium salt), sodium cyanate can be used as a quenching agent in steel processing. In the production of herbicides, fungicides, and insecticides, it is used to replace phosgene to synthesize various types of isocyanates to produce carbamates or replace urea pesticides. As a pharmaceutical intermediate, it can produce drugs for Parkinson's disease, diabetes, epilepsy and other diseases. Sodium cyanate is also used as a dye intermediate and as a catalyst in the production of acrylic polymers to maintain the whiteness of the fibers. Sodium cyanate can also be used as a photoinitiator. [0003] The synthetic method of sodium cyanat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01D7/00C01C1/24
Inventor 王嘉兴
Owner 南通华山实业有限公司
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