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Method for recovering melamine from melamine waste water and co-producing desulfurizer

A technology of melamine and desulfurizer, applied in separation methods, chemical instruments and methods, natural water treatment, etc., can solve the problems of undisclosed special materials and centrifugal technology, unexplained industrial applications, insufficient to cover operating costs, etc., Achieve the effect of saving treatment costs, achieving zero emissions, and saving ammonia sources

Active Publication Date: 2013-04-17
CHUANHUA GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, on the one hand, the method described in this article is an experimental research result, and the industrial application is not explained. On the other hand, the special materials and centrifugation technology described in it have not been disclosed, and there may be undisclosed special materials and centrifugal equipment used, etc. The cost of industrialization is higher, not enough to make up for the reduced operating costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The 10L melamine crystallization mother liquor wastewater (in this wastewater, water is 98.5%, OAT is 0.02%, melamine is 1.5%, ammonia is 0.1%) of 74 ℃ of 10L melamine crystallization mother liquor wastewater produced in the melamine wet production process is sent into ammonia Lower the temperature to 10°C in the cold heat exchanger, then adjust the pH value to 11 with liquid ammonia, and then send it to the cyclone for solid-liquid separation to obtain melamine slurry and the remaining ammonia, OAT and trace melamine liquid two parts. The melamine slurry was dried to obtain 141 g of melamine with a purity of 98.2%, and the yield of melamine was 92%. The remaining liquid containing ammonia, OAT and trace amounts of melamine enters the desulfurizer storage tank, adjusts the mass percentage concentration of ammonia to 4% with liquid ammonia, and enters the simulated flue gas treatment process for desulfurization. After desulfurization, the final product containing ammoniu...

Embodiment 2

[0025] The 10L melamine crystallization mother liquor wastewater (in this wastewater, water is 97.8%, OAT is 0.04%, melamine is 1.4%, ammonia is 0.2%) of 68 ℃ of 10L melamine crystallization mother liquor wastewater produced in the melamine wet production process is sent into ammonia Lower the temperature to 5°C in the cold heat exchanger, then adjust the pH value to 10.8 with liquid ammonia, and then send it to the cyclone for solid-liquid separation to obtain melamine slurry and the remaining ammonia, OAT and trace melamine liquid two parts. The melamine slurry was dried to obtain 136 g of melamine with a purity of 98.1%, and the yield of melamine was 95%. The remaining liquid containing ammonia, OAT and trace melamine enters the desulfurizer storage tank, adjusts the mass percentage concentration of ammonia to 6% with ammonia water, and then enters the simulated flue gas treatment process for desulfurization. After desulfurization, the final product mainly contains ammonium...

Embodiment 3

[0027] The temperature that produces in the melamine wet production process is 70 ℃ of 1L melamine crystallization mother liquor wastewater (in this wastewater, water is 98.2%, OAT is 0.03%, melamine is 1.5%, and ammonia is 0.2%) into ammonia Lower its temperature to 1°C in a cold heat exchanger, then adjust its pH value to 10 with ammonia water with a mass percentage concentration of at least 10%, and then send it to a cyclone for solid-liquid separation to obtain melamine slurry and the remaining melamine-containing Ammonia, OAT and trace melamine liquid in two parts. The melamine slurry was dried to obtain 14.9 g of melamine with a purity of 98.2%, and the yield of melamine was 97%. The remaining liquid containing ammonia, OAT and trace melamine enters the desulfurizer storage tank, adjusts the mass percentage concentration of ammonia to 10% with waste ammonia water, and then enters the simulated flue gas treatment process for desulfurization. After desulfurization, the fin...

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PUM

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Abstract

The invention discloses a method for recovering melamine from melamine waste water and co-producing a desulfurizer. The method comprises the following steps of cooling waste melamine crystallization mother liquor produced in melamine wet production to a temperature of 1 to 15 DEG C, adjusting a pH value of the cooled waste melamine crystallization mother liquor to a pH value above 10 by ammonia, carrying out solid-liquid separation to obtain melamine slurry, feeding the melamine slurry back into melamine crystallization liquid adopted in the melamine wet production so as to carry out recovery, feeding a solution containing ammonia, OAT and a trace amount of melamine into a desulfurizer storage tank adopted in a coal boiler flue gas treatment flow, and adjusting an ammonia mass percent of the solution to a mass percent of 1 to 10% by ammonia or waste ammonia water, wherein the solution subjected to pH adjustment is utilized as an desulfurizer. The method can recover melamine in waste water, utilize fully an ammonia source of waste water, simplifies a waste melamine crystallization mother liquor treatment technology, and save a treatment cost. Through the method, process water produced by flue gas desulphurization can be directly fed back to a production technology for recycle, and thus no discharge, integrated utilization and waste recycle are realized.

Description

technical field [0001] The invention belongs to the technical field of recovering melamine, pyrolysis intermediate oxidation products and melamine deamination condensate (OAT) from melamine crystallization mother liquor wastewater. Specifically relates to a method for recovering melamine from melamine wastewater and co-producing a desulfurizing agent. Background technique [0002] Melamine production is divided into three processes: normal pressure method, medium pressure method and high pressure method. [0003] The characteristics of the process of producing melamine by the normal pressure method are: it belongs to the dry process, requires the use of catalysts, less equipment, short process, small one-time investment, short continuous production cycle, process water containing ammonia and carbon dioxide can be recycled or used in other ammonia The recovery device is used, and there is basically no process wastewater discharge. But because the materials are all in solid ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04B01D53/77B01D53/50C07D251/54C02F103/36
Inventor 杨诚辜凯德郑述平刘红宇肖斌谢成贤付稚俊袁秋礼张晓蓉
Owner CHUANHUA GRP