Process for inducing crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater

A rare earth metal, induced crystallization technology, used in metallurgical wastewater treatment, water/sewage treatment, water treatment parameter control, etc., can solve the problems of insufficient reaction, large actual amount, slow sedimentation, etc., to improve sedimentation separation and crystallization. effect, reduce surface tension, accelerate the effect of reaction crystallization

Inactive Publication Date: 2018-11-09
NANCHANG HANGKONG UNIVERSITY
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  • Abstract
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  • Application Information

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Problems solved by technology

However, the solubility of lime is low, so it can only be added in the form of emulsion, and the produced CaF 2 Precipitate wrapped in Ca(OH) 2 The surface of the particles prevents them from being fully reacted, and the actual amount is much greater than the theoretical amount
CaF 2 It has colloidal properties, slow settling, difficult solid-liquid separation, low purity, and difficult to recycle
The more important rare metal smelting wastewater has complex components and contains other substances that can increase CaF 2 Solubility ions and complex forms of fluoride that do not participate in the neutralization reaction exist. After treatment, the fluorine content in wastewater can only be reduced to 15mg / L. It is difficult to meet the national standard first-level discharge standard. Chemical precipitation and fluoride removal are facing great challenges.

Method used

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  • Process for inducing crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater
  • Process for inducing crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater

Examples

Experimental program
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Effect test

Embodiment 1

[0025] The process of inducing the crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater, the specific steps are as follows:

[0026] (1) Fill 2g calcium fluoride seed crystal into the fluidized bed reactor, open 2.0m 3 The reflux water of / h flow rate makes the crystal seed in the reactor in a fluidized state at normal temperature;

[0027] (2) The high-fluorine wastewater with a fluorine content of 1.2g / L was treated with 0.5m 3 / h flow, calcium solution at 1.0m 3 / h flow rate, the temperature of the reflux water is raised to 70°C, and the waste water and the calcium solution are continuously reacted in the fluidized bed for 1 hour;

[0028] (3) Lower the temperature of the reflux water to 30°C, inject helium into the fluidized bed reactor, and use 1.2m of high-fluorine wastewater 3 / h flow, calcium solution at 2.5m 3 The flow rate of / h makes the waste water and calcium solution react in the fluidized bed for 0.5h;

[0029] (4) Conti...

Embodiment 2

[0036] The process of inducing the crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater, the specific steps are as follows:

[0037] (1) Fill 10g calcium fluoride seed crystal into the fluidized bed reactor, open 2.5m 3 The reflux water of / h flow rate makes the crystal seed in the reactor in a fluidized state at normal temperature;

[0038] (2) The high-fluorine wastewater with a fluorine content of 2.2g / L was treated with 0.8m 3 / h flow, calcium solution at 1.5m 3 / h flow rate, the temperature of the reflux water is raised to 75°C, and the waste water and the calcium solution are continuously reacted in the fluidized bed for 1.2h;

[0039] (3) Lower the temperature of the reflux water to 35°C, inject helium into the fluidized bed reactor, and use 1.3m of high-fluorine wastewater 3 / h flow, calcium solution at 2.8m 3 The flow rate of / h makes the waste water and calcium solution react in the fluidized bed for 0.8h;

[0040] (4) Continu...

Embodiment 3

[0046] The process of inducing the crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater, the specific steps are as follows:

[0047] (1) Fill 15g calcium fluoride seed crystal into the fluidized bed reactor, open 3.0m 3 The reflux water of / h flow rate makes the crystal seed in the reactor in a fluidized state at normal temperature;

[0048] (2) The high-fluorine wastewater with a fluorine content of 2.0g / L was treated with 0.5m 3 / h flow, calcium solution at 1.5m 3 / h flow rate, the temperature of the reflux water is raised to 80°C, and the waste water and the calcium solution are continuously reacted in the fluidized bed for 1.2h;

[0049] (3) Lower the temperature of the reflux water to 40°C, inject helium into the fluidized bed reactor, and use 1.5m of high-fluorine wastewater 3 / h flow, calcium solution at 2.5m 3 The flow rate of / h makes the waste water and calcium liquid react in the fluidized bed for 1h;

[0050] (4) Continue t...

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PUM

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Abstract

The invention discloses a process for inducing crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater, which adopts fluidized bed crystallization and applies an electromagnetic field at the same time. , temperature and other crystallization kinetic process parameters, accelerate the crystallization rate of CaF2, realize high-efficiency crystallization, and obtain high-purity CaF2, thereby realizing the deep removal of fluorine and the resource utilization of CaF2 at the same time.

Description

technical field [0001] The invention relates to a technique for inducing crystallization of calcium fluoride in rare earth metal smelting high-fluorine wastewater, which belongs to the field of wastewater treatment. Background technique [0002] South Jiangxi is rich in rare metal mineral resources. At the same time, most of the tantalum, niobium, tungsten and some rare earth smelting enterprises in this area also produce a large amount of high-fluorine wastewater, and its fluorine content is generally 1.2-3.2g / L, exceeding the standard by 120-320 times. Fluorine-containing wastewater is the most harmful wastewater produced in the rare metal smelting process, the most complex in nature, and the most difficult to treat. It is a difficult problem that needs to be solved urgently. In fact, the low-cost and effective method for removing fluoride from rare metal smelting wastewater is still the calcium precipitation method. but chemically precipitated CaF 2 It is not just a che...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/52C02F1/48C02F1/00C02F103/16
CPCC02F1/00C02F1/52C02F1/5236C02F2001/5218C02F2103/16C02F2209/02
Inventor 曾桂生隋幸桢关乾黄盛肖民
Owner NANCHANG HANGKONG UNIVERSITY
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