Method for treating fluorine-containing wastewater and recycling fluorine-containing sludge produced by treatment of fluorine-containing wastewater

A waste water treatment and recycling technology, applied in fluorine/hydrogen fluoride, chemical instruments and methods, water/sewage multi-stage treatment, etc., can solve the problems of shortage of fluorine resources, large sludge output, limited outlets, etc., and reduce mining volume , cost reduction, and the effect of reducing waste

Active Publication Date: 2014-06-11
ACAD OF ENVIRONMENTAL PLANNING & DESIGN GRP CO LTD NANJING UNIV
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  • Claims
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Problems solved by technology

The fluorine-containing sludge obtained in the wastewater treatment process is used as a substitute for natural fluorite to produce hydrogen fluoride to realize the resource utilization of sludge. It can not only solve the contradiction between the current large sludge output and limited outlets, but also eliminate the secondary pollution of fluorine. At the same time, it can solve the increasingly serious problem of shortage of fluorine resources

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  • Method for treating fluorine-containing wastewater and recycling fluorine-containing sludge produced by treatment of fluorine-containing wastewater

Examples

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Effect test

Embodiment 1

[0032] The method for the treatment of fluorine-containing wastewater and the resource utilization of the generated fluorine-containing sludge in this embodiment, the steps are as follows:

[0033] (a) 1 ton of fluorine-containing waste water (F-concentration of 7200 mg / L after testing) flows into the first reaction tank, adding waste hydrochloric acid to adjust the pH to 2.1, adding 21.0 kg of calcium chloride, stirring to make it fully mixed, and standing still to make the fluorine Calcium oxide crystal precipitation;

[0034] (b) Extract the crystallized calcium fluoride slurry from the bottom of the first reaction tank, and transport it to the calcium fluoride wet sludge storage tank. After the calcium fluoride slurry is precipitated, the upper liquid flows into the second reaction tank, and the bottom solid is dried at 40°C for 15 hours to obtain 12.7 kg of calcium fluoride dry sludge (86% recovery rate), with a particle size of 38.5 μm and a purity of 94.8%.

[0035] (...

Embodiment 2

[0040] The method for the treatment of fluorine-containing wastewater and the resource utilization of the generated fluorine-containing sludge in this embodiment, the steps are as follows:

[0041] (a) 1t of fluorine-containing waste water (F-concentration of 3500mg / L after testing) flows into the first reaction tank, add mixed waste acid containing hydrochloric acid and sulfuric acid to adjust the pH to 5, add 10.2kg of calcium chloride, stir to make it fully Mix and let stand to precipitate calcium fluoride crystals;

[0042] (b) Extract the crystallized calcium fluoride slurry from the bottom of the first reaction tank, and transport it to the calcium fluoride wet sludge storage tank. After the calcium fluoride slurry was centrifuged, the upper liquid flowed into the second reaction tank, and the bottom solid was dried at 50°C for 13 hours to obtain 5.4kg of calcium fluoride dry sludge (75% recovery rate), with a particle size of 5.2 μm and a purity of 93.5%.

[0043] (c)...

Embodiment 3

[0048] The method for the treatment of fluorine-containing wastewater and the resource utilization of the generated fluorine-containing sludge in this embodiment, the steps are as follows:

[0049] (a) 1 ton of fluorine-containing waste water (F-concentration of 5800 mg / L after testing) flows into the first reaction pool, adding waste sulfuric acid to adjust the pH to 3.5, adding 16.9 kg of calcium chloride, stirring to make it fully mixed, and standing still to make the fluorine Calcium oxide crystal precipitation;

[0050] (b) Extract the crystallized calcium fluoride slurry from the bottom of the first reaction tank, and transport it to the calcium fluoride wet sludge storage tank. After the calcium fluoride slurry is precipitated, the upper liquid flows into the second reaction tank, and the bottom solid is dried at 70°C for 10 hours to obtain 9.6 kg of calcium fluoride dry sludge (81% recovery rate), with a particle size of 20.6 μm and a purity of 84.2%.

[0051] (c) th...

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Abstract

The invention discloses a method for treating fluorine-containing wastewater and recycling fluorine-containing sludge produced by treatment of fluorine-containing wastewater. The method comprises the steps of reacting the fluorine-containing wastewater with calcium chloride under the acidic condition formed by adding a waste acid matter, performing crystallization sedimentation to remove most fluorine ions from the wastewater to form high-purity fluorine-containing sludge, removing dissolved calcium fluoride and other impurities from supernate through alkali sedimentation to form a small amount of fluorine-containing sludge with relatively low purity, then neutralizing the supernate, and discharging effluent, wherein the concentration of fluorine ions of the effluent is lower than 10 mg/L and accords with national discharge standards; drying the high-purity fluorine-containing sludge, then adding the dried sludge and excessive sulfuric acid into a reactor with a stirring device, reacting at 150-300 DEG C to prepare hydrogen fluoride, and condensing and rectifying the obtained crude hydrogen fluoride gas to obtain an anhydrous hydrogen fluoride product.

Description

technical field [0001] The invention belongs to the field of sewage treatment and resource utilization, and relates to a method for the treatment of fluorine-containing wastewater in the fluorine chemical industry and the resource utilization of fluorine-containing sludge generated during the treatment process. treatment and a method for producing hydrogen fluoride using fluorine-containing sludge as a raw material. Background technique [0002] In recent years, my country's fluorine chemical industry has developed rapidly, and the fluorine chemical market is generally growing at a rate of 15% to 20%. In the future, the fluorine chemical industry will also be one of the fastest growing industries in the chemical industry . However, the environmental threat brought by the rapid development of the fluorine chemical industry has become the biggest obstacle to the sustainable development of the industry. On the one hand, due to the large amount of fluorine-containing wastewater...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F11/00C01B7/19C04B11/00C02F101/14
Inventor 陆朝阳王梦乔姚琪周涛江野立张以飞林锋董迎雯
Owner ACAD OF ENVIRONMENTAL PLANNING & DESIGN GRP CO LTD NANJING UNIV
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