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Method for comprehensive treatment and recycling of ammonium sulfate wastewater of rare-earth smelting

A comprehensive wastewater treatment technology, applied in chemical instruments and methods, water/sewage multi-stage treatment, water/sludge/sewage treatment, etc., can solve the problem of large fluctuations in the water quality of ammonium sulfate wastewater, the inability to effectively reduce the hardness of wastewater, and equipment Scaling can not run stably and other problems, to achieve the effect of economical and effective wastewater treatment and reuse, good social and economic benefits, and reduce treatment costs

Active Publication Date: 2017-02-15
JIANGSU WODEKAI ENVIRONMENTAL PROTECTION TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the large fluctuations in the grade of rare earth concentrate used in production (20%-50%), the proportion and amount of raw materials such as magnesium oxide and sulfuric acid used in the production process are also constantly changing, resulting in the water quality of ammonium sulfate wastewater generated in the production process. The fluctuation range is large, and wastewater treatment is very difficult
[0004] At present, there are more or less methods for treating rare earth wastewater, and there are problems such as low wastewater reuse rate, inability to effectively reduce the hardness of wastewater, serious scaling of equipment and unstable operation, etc.

Method used

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  • Method for comprehensive treatment and recycling of ammonium sulfate wastewater of rare-earth smelting

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Carbon-precipitated ammonium sulfate wastewater from a northern rare earth enterprise, wastewater quality: total hardness 130-230mmol / L, ammonia nitrogen 3500-5000mg / L, conductivity 30,000-50,000μs / cm, pH6-8, sulfate radical 21000-32000mg / L, salinity 3%-4.5%.

[0032] Add lime to the rare earth smelting ammonium sulfate wastewater while stirring, that is, a large amount of white precipitate appears, continue to add lime to stabilize the pH of the wastewater at 11; The sediment at the bottom of the pool is sent to the plate and frame filter by a mud pump for filtration, and the obtained filtrate and supernatant are combined; carbon dioxide gas is added to the clear liquid obtained by the neutralization reaction, and the amount of carbon dioxide added is 0.2m 3 per ton of water (standard state), the reaction time was 2 hours, and white calcium carbonate crystals were separated out at this moment; the suspension after the acidification reaction finished entered the floati...

Embodiment 2

[0034] Carbon-precipitated ammonium sulfate wastewater from a northern rare earth enterprise, wastewater quality: total hardness ≥ 200mmol / L, ammonia nitrogen 3500-5000mg / L, conductivity 3-50,000μs / cm, pH6-8, sulfate radical 21000-32000mg / L, Salinity 3%-4.5%.

[0035] Add calcium hydroxide to the rare earth smelting ammonium sulfate wastewater while stirring until the pH of the wastewater reaches 14, stop stirring to precipitate insoluble solid particles such as calcium sulfate, collect the supernatant, and send the bottom sediment to a plate and frame filter for filtration to obtain sulfuric acid Calcium and other solid residues, the supernatant and supernatant obtained by filtration are combined; carbon dioxide gas is added to the combined supernatant, and the amount of carbon dioxide added is 0.4m 3 / ton of water (standard state) and maintain the reaction for 0.5 hours, the acidification reaction forms a calcium carbonate precipitate, and the suspension is sent to a floati...

Embodiment 3

[0037] Carbon-precipitated ammonium sulfate wastewater from a rare earth enterprise, wastewater quality: total hardness ≥ 200mmol / L, ammonia nitrogen 3500-5000mg / L, conductivity 30,000-50,000μs / cm, pH6-8, sulfate radical 21000-32000mg / L, Salinity 3%-4.5%.

[0038]Add lime to the rare earth smelting ammonium sulfate wastewater and stir until the neutralization reaction is completed when the reaction pH is 13, and the suspension containing calcium sulfate is sent to a plate and frame filter for filtration to obtain clear liquid and solid residues such as calcium sulfate; Add carbon dioxide gas to the water, the amount of carbon dioxide added is 0.3 3 / ton of water (standard state), the reaction time was 1.2 hours, and the acidification reaction formed calcium carbonate precipitation, and the suspension was sent to the floating flow type sedimentation tank for precipitation for 5 hours to obtain clarified liquid, and the bottom precipitation was sent to filter to obtain solid ca...

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Abstract

The invention discloses a method for comprehensive treatment and recycling of ammonium sulfate wastewater of rare-earth smelting and belongs to the technical field of environmental protection. The method comprises the steps: adding a neutralizer into the ammonium sulfate wastewater of rare-earth smelting so as to remove calcium, magnesium, iron and aluminum ions, and introducing carbon dioxide gas into the wastewater so as to further remove the calcium ions; enabling clarified liquor to enter a stripping deamination tower, and carrying out distillation so as to remove ammonia nitrogen from the clarified liquor and recover condensed weak aqua ammonia; and adjusting the pH of the ammonia-nitrogen-removed clarified liquor, carrying out filtration by a reverse osmosis membrane, and recycling purified water obtained through filtration to production. According to the method, the pollution problem of the high-hardness, high-alkalinity, high-ammonia-nitrogen and high-salinity ammonium sulfate wastewater of rare-earth smelting is solved, and the treatment cost of the ammonium sulfate wastewater of rare-earth smelting is reduced through recovering byproducts such as high-purity water, weak aqua ammonia and calcium carbonate, so that the method has good social and economic benefits.

Description

technical field [0001] The invention relates to a method for comprehensive treatment and reuse of rare earth smelting ammonium sulfate wastewater, which belongs to the technical field of environmental protection. Background technique [0002] Rare earth refers to the general term of 17 elements such as lanthanides and scandium and yttrium in the periodic table of chemical elements. Because rare earth elements have excellent physical and chemical properties, they are widely used in the fields of electronics, petrochemicals, metallurgy, machinery, agriculture and environmental protection. In recent years, my country's rare earth industry has developed rapidly, especially in Inner Mongolia Autonomous Region, where rare earth is the pillar industry. However, the problem of wastewater pollution generated during rare earth smelting and processing has become increasingly prominent. Taking Baotou City as an example, the annual rare earth wastewater generated is about 2 million tons...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04
Inventor 李祖强王彪
Owner JIANGSU WODEKAI ENVIRONMENTAL PROTECTION TECH CO LTD
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