A low-cost ferric phosphate wastewater treatment method containing ammonia nitrogen

A technology for ammonia nitrogen wastewater and treatment methods, applied in multi-stage water treatment, water/sewage treatment, water/sewage multi-stage treatment, etc., can solve the problems of low economic value and high cost of nitrogen recovery process, and achieve high economic value, Evaporation cost reduction and treatment cost reduction effects

Active Publication Date: 2021-10-01
HUNAN YACHENG NEW MATERIAL CO LTD
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AI Technical Summary

Problems solved by technology

[0005] Above-mentioned technical scheme, the product NH that recovery nitrogen process prepares 4 h 2 PO 4 As a phosphorus source in the production process of iron phosphate, its market price is much lower than the raw material phosphoric acid used in the nitrogen recovery process, resulting in high cost of the nitrogen recovery process and low economic value of the process.

Method used

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  • A low-cost ferric phosphate wastewater treatment method containing ammonia nitrogen

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preparation example Construction

[0040] The preparation process of iron phosphate is as follows:

[0041] Ferric phosphate reaction stock solution (NH 4 h 2 PO 4 , FeSO 4 、H 3 PO 4 mixture) and H 2 o 2 Mixing, oxidation-reduction reaction occurs, the reaction formula is as follows:

[0042] 2NH 4h 2 PO 4 +2FeSO 4 +H 2 o 2 =2FePO 4 ↓+2NH 4 HSO 4 +2H 2 o

[0043] H in the reaction material 3 PO 4 Does not directly participate in the reaction, its main function is to adjust the acidity in the reaction process, PO in the ferric phosphate mother liquor 4 3- less.

[0044] The reaction slurry is hydraulically filtered to obtain iron phosphate filter cake and iron phosphate mother liquor, and the iron phosphate filter cake is washed and calcined to obtain iron phosphate products; the pH value of the iron phosphate mother liquor is 1-2.5, mainly containing NH 4 HSO 4 、H 3 PO 4 , that is, the ferric phosphate mother liquor mainly contains NH 4 + 、H + , SO 4 2- 、PO 4 3- , In addition, i...

Embodiment 1

[0049] see figure 1 , is a schematic flow chart of the low-cost ferric phosphate ammonia nitrogen-containing wastewater treatment method provided by the present invention. A method for treating waste water containing ammonia nitrogen with low-cost ferric phosphate, comprising the steps of:

[0050] Step S1, adding an appropriate amount of Ca(OH) to the ferric phosphate mother liquor 2 , generate calcium sulfate precipitate, filter the precipitate to obtain the first mixed solution, the first mixed solution mainly contains NH 4 + , SO 4 2- and PO 4 3- ;

[0051] The main reaction equation is as follows:

[0052] Ca(OH) 2 +2NH 4 HSO 4 =CaSO 4 ↓+(NH 4 ) 2 SO 4 +2H 2 O (1)

[0053] Impurity removal reaction:

[0054] Fe 3+ +3OH - =Fe(OH) 3 ↓ (2)

[0055] In this reaction, the pH value of the neutralization reaction system is controlled to be 6-8 to avoid PO in the system 4 3- with Ca 2+ The reaction produces a calcium phosphate precipitate.

[0056] Thus,...

Embodiment 2

[0081] A method for treating waste water containing ammonia nitrogen with low-cost ferric phosphate, comprising the steps of:

[0082] Step S1, adding an appropriate amount of Ca(OH) to the ferric phosphate mother liquor 2 , generate calcium sulfate precipitate, filter the precipitate to obtain the first mixed solution, the first mixed solution mainly contains NH 4 + , SO 4 2- and PO 4 3- ;

[0083] In this process, Ca(OH) 2 The purity is 95%, and it is mixed with the SO in the iron phosphate mother liquor 4 2- The molar ratio is 1:2; the mass concentration of the first mixed solution obtained by filtration is 4%, and the pH value is 6.

[0084] The filtered first mixed solution is subjected to ion exchange resin removal of impurities in the resin adsorption tower to further remove iron ions in the first mixed solution, so that the content of Fe ions in the first mixed solution is lower than 3-5ppm.

[0085] Step S2, performing first membrane concentration on the fir...

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Abstract

The invention discloses a low-cost iron phosphate wastewater treatment method containing ammonia nitrogen. This includes the steps of: adding an appropriate amount of Ca(OH) to the ferric phosphate mother liquor 2 , adjust the pH value to 6-8, generate calcium sulfate precipitate, filter the precipitate to obtain the first mixed solution, the first mixed solution mainly contains NH 4 + , SO 4 2‑ and PO 4 3‑ Concentrating the first mixed solution with the first membrane to obtain the second mixed solution; performing MVR evaporation on the second mixed solution to separate and obtain ammonium sulfate crystals and ammonium phosphate crystals; washing and drying the crystals to obtain ammonium sulfate and ammonium phosphate finished products. The low-cost ferric phosphate ammonia nitrogen-containing wastewater treatment method provided by the invention has a simple process and the raw material used is Ca(OH) 2 , can reduce the salt concentration in the system, thereby reducing the amount of water entering the MVR for evaporation, and correspondingly reducing the evaporation cost. At the same time, Ca(OH) 2 As a solid, it will not increase the water volume of the system, thereby reducing the treatment capacity and treatment cost of the first membrane concentration system.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a low-cost iron phosphate wastewater treatment method containing ammonia nitrogen. Background technique [0002] With the development of the times and the advancement of science and technology, human beings have an increasing demand for new energy materials. Among them, lithium batteries have been widely used in various mobile communication devices and vehicles due to their advantages such as high voltage, high energy density, good cycle performance, and good high-temperature characteristics. The cathode material of lithium batteries mainly uses iron phosphate. The traditional preparation process of iron phosphate mainly includes co-precipitation method, hydrothermal method, etc., among which co-precipitation method is widely used. [0003] The co-precipitation method refers to dissolving the iron source and phosphorus source, adding other compounds to p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C01C1/24C01B25/37C01B25/28C02F101/16C02F101/10
CPCC01B25/28C01B25/375C01C1/24C02F1/001C02F1/048C02F1/38C02F1/42C02F1/44C02F1/441C02F1/66C02F9/00C02F2001/007C02F2101/105C02F2101/16C02F2301/08
Inventor 李智军孙资光丁建华
Owner HUNAN YACHENG NEW MATERIAL CO LTD
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