A method for crystallization and separation of ammonia nitrogen in ammonia exchange wastewater

A technology of crystallization separation and ammonia exchange, which is applied in chemical instruments and methods, water pollutants, multi-stage water treatment, etc., can solve the complex and uneven structure of MAP double salt crystallization products, and the difficulty in the removal rate of ammonia nitrogen reaching a high efficient level. Comprehensive waste utilization efficiency and other issues to achieve the effect of improving comprehensive utilization efficiency, low utilization efficiency, and avoiding waste

Active Publication Date: 2018-10-26
CHINA TIANCHEN ENG +1
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Problems solved by technology

[0005] In the prior art, the method of generating MAP double salt is often used to treat ammonia nitrogen wastewater, but it has the following disadvantages: (1) the removal rate of ammonia nitrogen is difficult to reach a high-efficiency level, and it often needs to be coordinated with other treatment methods. It can make the wastewater meet the discharge standard and increase the complexity of the treatment process; (2) The structure of the MAP double salt crystallization product is complex and uneven, which is not conducive to the later filtration and drying operations, and affects the comprehensive utilization efficiency of waste; (3) The utilization efficiency of drugs Low, resulting in waste of pharmaceutical raw materials, and easy to cause secondary pollution of phosphate

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  • A method for crystallization and separation of ammonia nitrogen in ammonia exchange wastewater

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Embodiment 1

[0027] Dissolve phosphate in SAPO molecular sieve ammonia exchange wastewater, the wastewater is ammonium chloride wastewater, the initial concentration of ammonia nitrogen is 14000mg / L, the phosphate is dipotassium hydrogen phosphate, and the dissolution temperature is 26.4°C, first add phosphoric acid to the wastewater The dosage of salt and phosphate is NH in wastewater 4 + ionizable PO in phosphate 4 3- The molar ratio is n(NH 4 + ): n(PO 43- )=1:1.2, after the phosphate is completely dissolved, the magnesium salt is added to the solution, the magnesium salt is magnesium chloride, and the dosage of the magnesium salt is NH 4 + ionizable Mg in magnesium salt 2+ The molar ratio is n(NH 4 + ): n (Mg 2+ )=1:1.2; add saturated NaOH solution dropwise to control the pH value of the reaction solution to 7.5, and react for 30 minutes; add magnesium chloride twice, and the dosage of the second magnesium salt is equal to the NH 4 + ionizable Mg in the secondary magnesium ...

Embodiment 2

[0029] Dissolve phosphate in SAPO molecular sieve ammonia exchange wastewater, the wastewater is ammonium nitrate wastewater, the initial concentration of ammonia nitrogen is 1000mg / L, the phosphate is disodium hydrogen phosphate, and the dissolution temperature is 25.4°C, first add phosphate to the wastewater , the dosage of phosphate is NH in wastewater 4 + ionizable PO in phosphate 4 3- The molar ratio is n(NH 4 + ): n(PO 4 3- )=1:1.0, after the phosphate is completely dissolved, the magnesium salt is added to the solution, the magnesium salt is magnesium oxide, and the dosage of the magnesium salt is NH 4 + ionizable Mg in magnesium salt 2+ The molar ratio is n(NH 4 + ): n (Mg 2+ )=1:1.0; add saturated NaOH solution dropwise to control the pH value of the reaction solution to 8.0, and react for 20 minutes; 4 + ionizable Mg in the secondary magnesium salt 2+ The molar ratio is n(NH 4 + ): n (Mg 2+ )=1:0.1, add saturated NaOH solution dropwise to control the...

Embodiment 3

[0031] Dissolve phosphate in SAPO molecular sieve ammonia exchange wastewater, the wastewater is ammonium nitrate wastewater, the initial concentration of ammonia nitrogen is 6000mg / L, the phosphate is sodium dihydrogen phosphate, and the dissolution temperature is 28.7°C, first add phosphate to the wastewater , the dosage of phosphate is NH in wastewater 4 + ionizable PO in phosphate 4 3- The molar ratio is n(NH 4 + ): n(PO 4 3- )=1:1.0, after the phosphate is completely dissolved, the magnesium salt is added to the solution, the magnesium salt is magnesium sulfate, and the dosage of the magnesium salt is the amount of NH in the wastewater 4 + ionizable Mg in magnesium salt 2+ The molar ratio is n(NH 4 + ): n (Mg 2+ )=1:1.1; add saturated NaOH solution dropwise to control the pH of the reaction solution to 8.5, react for 30 minutes; 4 + ionizable Mg in the secondary magnesium salt 2+ The molar ratio is n(NH 4 + ): n (Mg 2+ )=1:0.1, add saturated NaOH solution...

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Abstract

The invention provides a crystallization separation method for ammonia nitrogen in ammonia exchange wastewater. The crystallization separation method includes: throwing phosphate and magnesium salt into the wastewater for the first time, and after reacting for a specific period of time, throwing magnesium salt into the wastewater for the second time for reacting, wherein the phosphate and the magnesium salt, which are thrown for the first time, can ionize to obtain PO4<3-> and Mg<2+> in the whole reacting process, and a molar ratio of NH4<+> in the wastewater to the PO4<3-> to the Mg<2+> satisfies that n(NH4<+>): n(PO4<3->): n(Mg<2+>)=1:(1-1.3):(1-1.3); the magnesium salt thrown for the second time can ionize to obtain Mg<2+> in the whole reacting process, and a molar ratio of NH4<+> in the wastewater to the Mg<2+> satisfies that n(NH4<+>): n(Mg<2+>)=1:(0.1-0.7); in the process of throwing the magnesium salt for the second time, the NH4<+> in the wastewater is measured according to initial wastewater. By the crystallization separation method, ammonia nitrogen concentration in the wastewater can be reduced efficiently, and secondary pollution is avoided.

Description

technical field [0001] The invention belongs to the technical field of wastewater resource treatment, and in particular relates to a crystallization and separation method for ammonia nitrogen in ammonia-exchange wastewater, and is especially suitable for the treatment of ammonia-exchange wastewater by SAPO molecular sieves. Background technique [0002] Nitrogen in wastewater generally exists in four forms: organic nitrogen, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. Ammonia nitrogen wastewater mainly comes from pharmaceutical wastewater, coking wastewater, landfill leachate, pesticide wastewater, monosodium glutamate wastewater, chemical wastewater, gas wastewater, fertilizer wastewater, urban domestic sewage and aquaculture wastewater anaerobic digestion solution, etc. The excessive discharge of ammonia nitrogen wastewater is the main cause of water eutrophication. With the continuous improvement of global industrialization and urbanization, the discharge o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C01B25/45C02F101/16
CPCC01B25/451C02F9/00C02F2101/16C02F2301/08
Inventor 杨利强耿玉侠马国栋钱震左宜赞刘俊生石华王海国陈晨杜小宝李欢张蓉
Owner CHINA TIANCHEN ENG
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