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Method for preparing hydrogen fluoride and silicon tetrafluoride from waste materials containing calcium fluoride

A technology containing calcium fluoride and silicon tetrafluoride, applied in the direction of fluorine/hydrogen fluoride, hydrogen fluoride, fluosilicic acid, etc., can solve the problems of complex post-processing, pollution of the environment by waste containing calcium fluoride, etc., and achieve good social benefits and operation Convenience, the effect of eliminating environmental damage

Active Publication Date: 2020-05-19
衢州市鼎盛化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The present invention proposes a method for preparing hydrogen fluoride and silicon tetrafluoride from waste materials containing calcium fluoride, which solves the problems of waste materials containing calcium fluoride polluting the environment and complicated post-processing in the prior art

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The material used in this embodiment is: calcium fluoride sludge 1667kg (water content 40%) after the treatment of fluorine-containing waste water; ) 2 content is 9%wt, other impurity 7%wt.

[0039] at 8M 3 Add 4000kg of 35% fluosilicic acid to the reaction kettle; start stirring, and add 1667kg of sludge containing calcium fluoride; after 2 hours of normal pressure reaction, pump all the materials into the plate and frame filter press, and return the filtered fluosilicic acid to the reaction kettle kettle; then feed 680kg of cleaning water into the plate and frame filter press to clean the solid material, and the cleaned waste water is mixed with fluosilicic acid in the reaction kettle. The calcium fluorosilicate from the filter press is dried, then sent to a rotary reaction furnace and 833kg of 98% sulfuric acid is added; the reaction temperature is 450°C, and the reaction is carried out for 2 hours.

[0040] Reaction products: calcium sulfate 1135kg, hydrogen fluor...

Embodiment 2

[0042] The material used in this embodiment is: calcium fluoride sludge 1667kg (water content 40%) after the treatment of fluorine-containing waste water; ) 2 content is 9%wt, other impurity 7%wt.

[0043] at 8M 3 Add 4000kg of 35% fluosilicic acid to the reaction kettle; start stirring, and add 1667kg of sludge containing calcium fluoride; after 2 hours of normal pressure reaction, pump all the materials into the plate and frame filter press, and return the filtered fluosilicic acid to the reaction kettle kettle; then feed 680kg of cleaning water into the plate and frame filter press to clean the solid material, and the cleaned waste water is mixed with fluosilicic acid in the reaction kettle. The calcium fluorosilicate obtained by pressure filtration is sent into a rotary reaction furnace and 835 kg of 105% sulfuric acid is added; the heating temperature is 200° C., and the reaction is carried out for 4 hours.

[0044] Reaction products: calcium sulfate 1136kg, hydrogen fl...

Embodiment 3

[0046] The material used in this embodiment is: calcium fluoride sludge 1667kg (water content 40%) after the treatment of fluorine-containing waste water; ) 2 content is 9%wt, other impurity 7%wt.

[0047] at 8M 3 Add 4000kg of 35% fluosilicic acid to the reaction kettle; start stirring, and add 1667kg of sludge containing calcium fluoride; after 2 hours of normal pressure reaction, pump all the materials into the plate and frame filter press, and return the filtered fluosilicic acid to the reaction kettle kettle; then feed 680kg of cleaning water into the plate and frame filter press to clean the solid material, and the cleaned waste water is mixed with fluosilicic acid in the reaction kettle. The calcium fluorosilicate obtained by pressure filtration is sent into a rotary reaction furnace and 825 kg of 98% sulfuric acid is added; the heating temperature is 300° C., and the reaction is carried out for 3 hours.

[0048] Reaction products: calcium sulfate 1131kg, hydrogen flu...

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Abstract

The invention provides a method for preparing hydrogen fluoride and silicon tetrafluoride by using waste materials containing calcium fluoride. The method comprises the steps that firstly, the waste materials containing the calcium fluoride is reacted with fluosilicic acid to generate calcium fluosilicate and hydrofluoric acid, and the hydrofluoric acid reacts with silicon dioxide in the waste materials containing calcium fluoride to generate fluosilicic acid; secondly, the material in the first step is subjected to solid-liquid separation, and the fluosilicic acid is reused in the first step; thirdly, the calcium fluosilicate obtained through the separation in the second step is reacted with concentrated sulfuric acid, and hydrogen fluoride gas, silicon tetrafluoride gas and calcium sulfate solid are generated. In the method, process steps are continuous and cyclic, and a continuous production line can be formed; the fluosilicic acid is reacted with the calcium fluoride to generate an intermediate product, namely the calcium fluosilicate, so that the concentrated sulfuric acid and the calcium fluosilicate are subjected to a dry-media reaction to generate the silicon tetrafluoride gas and the hydrogen fluoride gas. By means of the method, the aims that environmental pollutions are reduced, the waste materials are changed into things of value and the economic efficiency is improved can be achieved.

Description

technical field [0001] The invention relates to the field of recycling calcium fluoride waste materials, in particular to a method for preparing hydrogen fluoride and silicon tetrafluoride from waste materials containing calcium fluoride. Background technique [0002] Inorganic and organic fluorine chemical production, electronic product production, photovoltaic power generation panel manufacturing, and glass thinning process all produce sludge containing calcium fluoride. The wastewater of these enterprises contains fluorine, and the wastewater treatment generally adopts the treatment method of "acid-base neutralization-coagulation sedimentation-sludge separation". The sludge produced after the reaction of fluorine and calcium in the wastewater contains calcium fluoride, substances such as silicon and calcium carbonate. [0003] The tailings after non-ferrous metal beneficiation also contain calcium fluoride, silicon dioxide, calcium carbonate (calcium hydroxide) and other...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B7/19C01B33/10
CPCC01B7/193C01B33/103
Inventor 应盛荣闻涛姜战应悦
Owner 衢州市鼎盛化工科技有限公司
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