Method for separating and recycling struvite crystal precipitates

A technology for separation and recovery and sediment, which is applied in chemical instruments and methods, phosphorus compounds, water pollutants, etc., can solve the problems of immature separation and recovery technology, complicated separation and recovery operations, and difficulty in maintaining crystal forms, and achieves the improvement of magnetic seeds. The recovery rate, the effect is obvious, and the effect of reducing the energy consumption of electrolysis

Inactive Publication Date: 2021-04-06
湖南鑫远环境科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, it is still difficult to popularize and apply this technology in engineering practice. In addition to the cost of dosing chemicals, the separation and recovery technology is still immature, which makes its separation and recovery operation more complicated, and it is difficult to maintain its crystal form, resulting in poor recovery effect. good

Method used

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Embodiment 1

[0025] Embodiment 1 of the present invention is: a method for separating and recovering struvite crystal precipitates, comprising the following steps:

[0026] S1. Transport the ammonia-nitrogen wastewater to be treated to the magnetization reactor, add phosphorus source (sodium phosphate) and control the nitrogen-phosphorus ratio (the ratio of the amount of nitrogen to phosphorus is 1:1.2), and the pH value under alkaline conditions (pH is 9.0) to add magnesium source (magnesium chloride) to produce partial precipitation, then dropwise magnesium source (total magnesium and phosphorus substance amount ratio is 1: 1) until the reaction is complete;

[0027] S2. Add magnetic seeds (magnetic powder, particle size 20-50 microns) at 100 mg / L, stir and mix evenly, and transport to the electroflocculation device (both positive and negative electrodes are iron electrodes, and the distance between the two electrodes is 5 cm). Pulse current (the current intensity is 5A / cm 3 , the freq...

Embodiment 2

[0030] Embodiment 2 of the present invention is: a method for separating and recovering struvite crystal precipitates, comprising the following steps:

[0031] S1. Transport the ammonia-nitrogen wastewater to be treated to the magnetization reactor, add phosphorus source (sodium phosphate) and control the nitrogen-phosphorus ratio (the ratio of the amount of nitrogen to phosphorus is 1:1.2), and the pH value under alkaline conditions (pH is 9.0) to add magnesium source (magnesium chloride) to produce partial precipitation, then dropwise magnesium source (total magnesium and phosphorus substance amount ratio is 1: 1) until the reaction is complete;

[0032] S2. Add magnetic seeds (magnetic powder, particle size 20-50 microns) at 100 mg / L, stir and mix evenly, and transport to the electroflocculation device (both positive and negative electrodes are iron electrodes, and the distance between the two electrodes is 5 cm). Pulse current (the current intensity is 10A / cm 3 , the fre...

Embodiment 3

[0035] Embodiment three of the present invention is: a method for separating and recovering struvite crystal precipitates, comprising the following steps:

[0036] S1. Transport the ammonia-nitrogen wastewater to be treated to the magnetization reactor, add phosphorus source (sodium phosphate) and control the nitrogen-phosphorus ratio (the ratio of the amount of nitrogen to phosphorus is 1:1.2), and the pH value under alkaline conditions (pH is 9.0) to add magnesium source (magnesium chloride) to produce partial precipitation, then dropwise magnesium source (total magnesium and phosphorus substance amount ratio is 1: 1) until the reaction is complete;

[0037] S2. Add magnetic seeds (magnetic powder, particle size 20-50 microns) at 100 mg / L, stir and mix evenly, and transport to the electroflocculation device (both positive and negative electrodes are iron electrodes, and the distance between the two electrodes is 5 cm). Pulse current (the current intensity is 8A / cm 3 , the ...

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Abstract

The method comprises the following steps: S1, conveying ammonia-nitrogen wastewater to be treated into a magnetizing reactor, adding a phosphorus source, controlling the nitrogen-phosphorus ratio, adding a magnesium source under an alkaline condition pH value to generate a part of precipitate, and dropwise adding the magnesium source under a neutral slightly alkaline pH value until the reaction is complete; S2, adding magnetic seeds, uniformly stirring and mixing, conveying into an electric flocculation device, and carrying out electric flocculation reaction by using pulse current; S3, conveying the wastewater treated in the step S2 into a magnetic separation device, discharging a liquid phase part after magnetic separation, and collecting a solid phase part; and S4, conveying the collected solid-phase part into a magnetic recovery device, recovering the magnetic seeds, and taking the rest part as the struvite crystal precipitate. According to the scheme of the embodiment of the invention, by combining electric flocculation and magnetic flocculation, struvite crystals can keep an intact crystal form structure, and the capacity of slowly releasing nitrogen and phosphorus is high.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for separating and recovering struvite crystal sediment. Background technique [0002] Both N and P are elements necessary for the growth of animals and plants, and one of the constituent elements of protein, which is of great significance to human beings. However, when nitrogen and phosphorus are excessive, it will have a negative impact on the growth of plants, such as causing eutrophication of water bodies. Therefore, nitrogen and phosphorus pollution has become one of the most important water pollution problems facing the world today. [0003] Struvite is a hydrated phosphate mineral, which contains 28.92% phosphorus pentoxide and 16.43% magnesium oxide. It belongs to the orthorhombic crystal system, and the crystals are often in the shape of axes, wedges, short columns or thick plates. Natural struvite is produced in the hard lumps of bird droppi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/08C01B25/45C02F101/16
CPCC02F9/00C01B25/451C02F1/5254C02F1/001C02F1/463C02F1/48C02F2101/16
Inventor 莫竞瑜
Owner 湖南鑫远环境科技股份有限公司
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