Method for preparing fluosilicic acid from calcium fluoride containing waste

A technology containing calcium fluoride and fluorosilicic acid, applied in the direction of fluorosilicic acid, halide silicon compound, calcium/strontium/barium sulfate, etc. Dealing with problems such as cost, to achieve the effect of low energy consumption, simple process and good social benefits

Active Publication Date: 2017-10-20
衢州市鼎盛化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The invention proposes a method for preparing fluosilicic acid from calcium fluoride-containing waste, which solves the problems in the prior art that th

Method used

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Experimental program
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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 calcium fluoride sludge; after 2 hours of normal pressure reaction, turn on the steam, heat the reaction kettle, and when the temperature of the material in the kettle reaches 75°C, slowly add 98% Sulfuric acid 835kg; Turn off steam after continuing to react for 3 hours. Pump all the materials into the plate and frame filter press, and return the filtered fluorosilicic acid to the reaction kettle; then pass 680kg of cleaning water into the plate and frame filter press to clean the solid materials, and the cleaned waste water is mixed with the fluorosilicic acid in the reaction kettle mix.

[0040] Reaction product: calcium sulfate 2388kg (moisture content 40%); the total w...

Embodiment 2

[0042] The material used in this embodiment is: calcium fluoride-containing tailings powder 2000kg (moisture content 0.5%) after nonferrous metal beneficiation; dry basis component: CaF Content is 35% wt, SiO Content is 45% wt, CaCO Content 15%wt, other impurities 5%wt.

[0043] at 8M 3 Add 4,000kg of 35% fluosilicic acid to the reactor; start stirring, and add 2,000kg of tailings powder containing calcium fluoride; after reacting for 2.5 hours at -0.05MPa, turn on the steam and heat the reactor. When the temperature of the material in the reactor reaches 190°C, Slowly add 1257 kg of 65% sulfuric acid; continue to react for 1 hour and then close the steam; feed cooling water to cool to normal temperature, and then vent the gas in the reactor. Pump all the materials into the plate and frame filter press, and the filtered fluorosilicic acid returns to the reactor; then feed 850kg of cleaning water into the plate and frame filter press to clean the solid materials, and the clean...

Embodiment 3

[0046] The material used in this embodiment is: low-grade fluorite ore powder 1500kg (moisture content 1.2%); Dry basis component: CaF Content is 45%wt, SiO Content is 26%wt, CaCO Content is 26%wt, other Impurities 4%wt.

[0047] Pretreatment: Add 1920kg of hydrochloric acid with a concentration of 22% to the plastic tank, then add 1500kg of low-grade fluorite ore powder; soak for 3 hours to convert CaCO3 into calcium chloride solution; then add 1000kg of clear water, pour all the materials into Centrifuge, separate calcium chloride solution, and clean up with clear water, obtain wet material 1549kg (water content 28%).

[0048] at 8M 3 Add 1549kg of wet materials into the reaction kettle; add 4000kg of 35% fluosilicic acid; start stirring. After reacting for 2 hours, turn on the steam and heat the reactor. When the material temperature in the kettle reaches 120° C., slowly add 782 kg of 104.5% oleum; continue to react for 1.5 hours and then turn off the steam. All the mate...

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Abstract

The invention provides a method for preparing fluosilicic acid from calcium fluoride containing waste. The method comprises the steps: (1) subjecting the calcium fluoride containing waste to a reaction with fluosilicic acid to produce calcium fluosilicate and hydrofluoric acid, wherein the hydrofluoric acid reacts with silicon dioxide in the calcium fluoride containing waste to produce fluosilicic acid; (2) adding sulfuric acid into the calcium fluosilicate obtained in the step (1), and carrying out a reaction to produce fluosilicic acid and calcium sulfate; and (3) carrying out solid-liquid separation on the fluosilicic acid and the calcium sulfate; and returning part of the fluosilicic acid to last step, and outputting part of the fluosilicic acid. According to the method, the processing steps are carried out in a continuous cycle manner, and thus, a continuous production line can be formed. The calcium fluosilicate, i.e., an intermediate product is produced through a reaction between the fluosilicic acid and calcium fluoride, so that the sulfuric acid reacts with calcium fluoride and silicon dioxide in a liquid phase to produce the fluosilicic acid. The method can achieve the aims of reducing environmental pollution, changing wastes into valuables and increasing economic efficiency.

Description

technical field [0001] The invention relates to the field of recycling waste materials containing calcium fluoride, in particular to a method for preparing fluosilicic acid 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 substances. ...

Claims

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Application Information

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IPC IPC(8): C01B33/10C01F11/46
CPCC01B33/103C01F11/46C01P2006/80C01P2006/82
Inventor 应盛荣闻涛姜战
Owner 衢州市鼎盛化工科技有限公司
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