Method for preparing calcium fluoride from fluorine-containing wastewater

A calcium fluoride and wastewater technology, applied in the direction of calcium/strontium/barium fluoride, calcium/strontium/barium halide, etc., can solve the problem that calcium fluoride solid cannot achieve controllable morphology, controllable particle size, purity, fluorine-containing Sludge secondary pollution, cumbersome process flow and other problems, to achieve the effect of good liquid-solid separation performance, controllable purity, and short process flow

Active Publication Date: 2021-07-16
INST OF PROCESS ENG CHINESE ACAD OF SCI
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AI Technical Summary

Problems solved by technology

Although the method improves the purity of calcium fluoride in the fluorine-containing sludge and solves the problem that small particles of calcium fluoride are difficult to settle and separate, the resulting fluorine-containing sludge still needs to be further separated into high-quality calcium fluoride solids. There is still the problem of secondary pollution, and the process of the method is cumbersome, the operation is complicated, the residence time is long, and the investment in equipment is high
[0012] In summary, although the prior art discloses some treatment methods for fluorine-containing wastewater, and some treatment methods can even separate high-purity calcium fluoride solids from fluoride-containing wastewater, there are still cumbersome technological processes and high equipment investment. , long residence time, secondary pollution of fluorine-containing sludge, etc., and the separated calcium fluoride solid cannot achieve controllable shape, controllable particle size, and controllable purity

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  • Method for preparing calcium fluoride from fluorine-containing wastewater
  • Method for preparing calcium fluoride from fluorine-containing wastewater
  • Method for preparing calcium fluoride from fluorine-containing wastewater

Examples

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Embodiment 1

[0079] This example provides a method for preparing calcium fluoride by utilizing fluorine-containing wastewater, which is fluorine-containing wastewater obtained from the condensation of fluidized bed waste gas from an aluminum fluoride factory in Henan, wherein the mass concentration of HF is 6.1 wt%; described preparation method adopts industrial lime as calcium-containing raw material, and its chemical composition is as shown in table 1:

[0080] Table 1

[0081]

[0082] Described preparation method comprises the steps:

[0083] (1) Mix industrial lime with an aqueous solution of ammonium chloride, and carry out a decomposition reaction at 95° C. for 0.05 h. After the reaction, the calcium chloride-containing feed liquid is subjected to liquid-solid separation to obtain a calcium chloride-containing solution and insoluble slag;

[0084] Wherein, the ratio of the ammonium chloride to the amount of CaO in the industrial lime is 1.6:1; the washing water obtained by washi...

Embodiment 2

[0091] This example provides a method for preparing calcium fluoride by utilizing fluorine-containing wastewater, which is a fluorine-containing wastewater from a fluorine chemical industry in Shandong, wherein the molar concentration of HF is 5.26 mol / L, and the molar concentration of HCl is 0.053 mol / L; The preparation method adopts calcium hydroxide as calcium-containing raw material:

[0092] Described preparation method comprises the steps:

[0093] (1) Calcium hydroxide is mixed with an aqueous solution of ammonium nitrate, and a decomposition reaction is carried out at 25° C. for 3 hours. After the reaction, the calcium nitrate-containing feed liquid is subjected to liquid-solid separation to obtain a calcium nitrate-containing solution and insoluble slag;

[0094] Wherein, the ratio of the amount of ammonium nitrate to calcium hydroxide is 2.4:1; the washing water obtained by washing the insoluble slag is mixed with the calcium nitrate-containing solution;

[0095] (...

Embodiment 3

[0101] This example provides a method for preparing calcium fluoride by using fluorine-containing wastewater, the fluorine-containing wastewater is fluorine-containing wastewater from a stainless steel factory in Jiangsu, wherein the mass concentration of HF is 7.66wt%, HNO 3 The mass concentration is 4.23wt%; Described preparation method adopts milk of lime as calcium-containing raw material:

[0102] Described preparation method comprises the steps:

[0103] (1) Mix milk of lime with an aqueous solution of ammonium chloride, and carry out a decomposition reaction at 60°C for 0.5h, and the reacted calcium chloride-containing feed liquid undergoes liquid-solid separation to obtain calcium chloride-containing solution and insoluble slag;

[0104] Wherein, the ratio of the ammonium chloride to the amount of CaO in the milk of lime is 2:1; the washing water obtained by washing the insoluble slag is mixed with the calcium chloride-containing solution;

[0105] (2) Contacting the ...

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Abstract

The invention relates to a method for preparing calcium fluoride from fluorine-containing wastewater. The preparation method comprises the following steps: carrying out decomposition reaction on a calcium-containing raw material and a dissolution medium, carrying out carbonization conversion reaction on a calcium-containing solution obtained by the decomposition reaction and carbon dioxide, and mixing and reacting a calcium carbonate solid obtained by the carbonization conversion reaction with the fluorine-containing wastewater and an additive to obtain a calcium fluoride solid. According to the preparation method, a high-quality artificial fluorite product with controllable morphology, controllable granularity and controllable purity can be prepared, and the fluorine resource recovery rate can be increased to 90% or above; and in addition, the preparation method realizes efficient circulation of the medium and carbon dioxide, avoids the generation of fluorine-containing sludge, and has the advantages of mild process conditions, no special requirements on equipment materials and types, strong industrial operability and wide application range.

Description

technical field [0001] The invention relates to the field of fluorine-containing wastewater treatment, in particular to a method for preparing calcium fluoride from fluorine-containing wastewater. Background technique [0002] Fluorspar, also known as fluorspar, is mainly composed of calcium fluoride (CaF 2 ), is my country's strategic mineral resources, has the scarcity and strategic significance of "rare earth", and its application fields cover chemical industry, metallurgy, cement, glass, ceramics, optics, electronics, new energy, national defense, medicine and other traditional and emerging industries . Because of its irreplaceable use, it is known as the "second rare earth". [0003] According to the "Mineral Commodity Summaries 2019" released by the US Geological Survey, the world's fluorite resource reserves are 310 million tons, and my country's fluorite resource reserves are 42 million tons, accounting for 13.5% of the world. However, my country's annual fluorspar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/22
CPCC01F11/22C01P2002/72C01P2004/03C01P2006/80C01P2004/61
Inventor 曹绍涛张毅张芳芳
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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