Recovering treatment method of wastewater containing fluorine and nitric acid

A technology for recycling and treating wastewater, applied in multi-stage water treatment, water/sewage treatment, chemical instruments and methods, etc., can solve the problem that fluoride ions and nitrate ions cannot be effectively utilized as resources, and achieve low cost and simple process. , the effect of improving the purity

Pending Publication Date: 2021-10-08
江苏电科环保有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] For the traditional treatment of fluorine-containing nitric acid wastewater, the problem that fluoride ions and nitrate ions cannot be effectively utilized as resources, the present invention provides a recovery treatment method for fluorine-containing and nitric acid wastewater, which can treat fluorine-containing nitric acid wastewater and recycle Fluoride and nitrate ions

Method used

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  • Recovering treatment method of wastewater containing fluorine and nitric acid
  • Recovering treatment method of wastewater containing fluorine and nitric acid

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Pass 1 ton of waste water containing 1% hydrofluoric acid and 40% nitric acid into the reaction tank, turn on the stirring device, continuously pour heavy calcium carbonate into it, and adjust the solution to neutral. Pass the mixed liquid in the reaction tank into the primary settling tank for 2 hours, and pass the settled sludge into the plate and frame filter press for pressure filtration. The supernatant is filtered through the tertiary filter and passed into the secondary in the settling tank.

[0029] The press-filtered filter cake was taken out, dried at 120° C. for 2 hours, and stored, and the press-filtered filtrate was passed into a secondary settling tank. Add 300g of PAC to the settling tank, after flocculation for 1 hour, filter the supernatant through a filter and pass it into the distillation kettle for vacuum distillation. The pressure of the distillation kettle is -0.03Mpa, the distillation temperature is 90°C, and the distillation time is 30min . The...

Embodiment 2

[0031] Pass 1 ton of waste water containing 3% hydrofluoric acid and 45% nitric acid into the reaction tank, turn on the stirring device, continuously pass heavy calcium carbonate into it, and adjust the solution to neutral. Pass the mixed solution in the reaction tank into the primary settling tank for 3 hours, and pass the settled sludge into the plate and frame filter press for pressure filtration. in the settling tank.

[0032] Take out the filter cake after pressure filtration, dry it at 120°C for 2 hours and store it. The filtrate after pressure filtration is passed into the secondary settling tank, and 400g of PAC is added to the settling tank. After flocculation for 2 hours, the supernatant is passed through the filter screen After filtration, it is passed into a distillation kettle for vacuum distillation. The pressure of the distillation kettle is -0.04Mpa, the distillation temperature is 80°C, and the distillation time is 40min. The sludge in the secondary settling...

Embodiment 3

[0034] Pass 1 ton of waste water containing 5% hydrofluoric acid and 50% nitric acid into the reaction tank, turn on the stirring device, continuously pour heavy calcium carbonate into it, and adjust the solution to neutral. Pass the mixed liquid in the reaction tank into the primary settling tank for 4 hours, and pass the settled sludge into the plate and frame filter press for pressure filtration. The supernatant is filtered through the tertiary filter and passed into the secondary in the settling tank.

[0035] Take out the filter cake after pressure filtration, dry it at 120°C for 2 hours, and store it. The filtrate after pressure filtration is passed into the secondary settling tank, and 500g of PAC is added to the settling tank, and the supernatant is passed through the filter screen after 3 hours of flocculation. After filtration, it is passed into a distillation kettle for vacuum distillation. The pressure of the distillation kettle is -0.05Mpa, the distillation temper...

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Abstract

The invention provides a recovering treatment method of wastewater containing fluorine and nitric acid. The methodcan be used for treating fluorine-containing nitric acid wastewater and recovering fluorine ions and nitrate ions in the fluorine-containing nitric acid wastewater, and comprises the following steps: 1, introducing fluorine-containing nitric acid wastewater into a reaction tank, adding calcium carbonate, and stirring until the solution is neutral; 2, introducing into a primary settling tank, settling for 2-4 hours, filtering the supernatant, introducing into a secondary settling tank, putting the sludge into a filter press, carrying out filter pressing, introducing the filtrate obtained by filter pressing into the secondary settling tank, drying the filter cake, and recovering; 3, adding a flocculating agent into the secondary settling tank, settling for 2-4 hours, filtering supernate, introducing the supernate into a distillation kettle, carrying out reduced pressure distillation, and discharging flocculated sludge for treatment; and 4, introducing a solid-liquid mixture obtained after distillation into a centrifugal machine, separating, refluxing a liquid obtained after centrifugation to the distillation kettle, drying solid particles, and then introducing into a calcium nitrate collecting tank for collecting.

Description

technical field [0001] The invention relates to the technical field of waste water recycling, in particular to a method for recycling and treating waste water containing fluorine and nitric acid. Background technique [0002] Photovoltaic and semiconductor industries produce a large amount of fluorine-containing nitric acid wastewater, the main component of which is nitric acid, accounting for 40% to 50%, and hydrofluoric acid accounting for 1% to 5%. The main hazards of wastewater are fluoride ions and nitrate ions, and direct discharge will cause water pollution and eutrophication. A common treatment method is to neutralize with lime to remove fluoride ions, and then perform biochemical treatment to remove total nitrogen. However, the content of nitrate ions in wastewater is high, and the direct biochemical treatment consumes a large amount of organic matter and consumes a lot of energy. Moreover, nitrate ions in wastewater have not been utilized as resources, resulting i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/10C01F11/22C01F11/38C02F101/14C02F101/16
CPCC02F9/00C01F11/22C01F11/38C02F1/583C02F1/52C02F1/001C02F1/5281C02F1/5245C02F1/04C02F1/38C02F11/122C02F2101/14C02F2101/163C02F2301/046C02F2301/08C02F2301/063
Inventor 郭维林邱立京李张成王堃
Owner 江苏电科环保有限公司
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