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CN-122010126-A - Resource utilization method of fluorine-containing silicon slag

CN122010126ACN 122010126 ACN122010126 ACN 122010126ACN-122010126-A

Abstract

The invention discloses a resource utilization method of fluorine-containing silicon slag, and relates to the field of resource utilization of fluorine-containing silicon slag. The preparation method comprises the steps of washing fluorine-containing silica slag, filtering to obtain crude silica, adding excessive crude silica into ammonium bifluoride solution, stirring and dissolving, filtering to obtain first filtrate after the reaction is completed, mixing and stirring part of the first filtrate with first ammonia water, ageing to obtain silica gel seed crystal, mixing and stirring the silica gel seed crystal and the rest of the first filtrate, adding second ammonia water under the stirring condition, continuously stirring to perform ammonolysis reaction until crystallization is completed, and filtering to obtain a silica filter cake and the second filtrate. The whole process route of the invention uses fluorine-containing silica slag as raw material, has wide raw material sources, synthesizes white carbon black products through the preparation of seed crystals, has high product quality, mild reaction conditions, recycling of raw materials, high comprehensive utilization degree and no secondary waste.

Inventors

  • LIU SONG
  • JIANG CAN
  • PAN QINGXIANG
  • Tian Zhengying
  • SUN FUQIANG
  • ZHANG YANAN

Assignees

  • 湖北九宁新材料有限公司

Dates

Publication Date
20260512
Application Date
20260213

Claims (10)

  1. 1. A resource utilization method of fluorine-containing silicon slag is characterized by comprising the following steps: s1, washing fluorine-containing silicon slag, and filtering to obtain crude silicon dioxide and fluosilicic acid aqueous solution; S2, adding excessive crude silicon dioxide into ammonium bifluoride solution, stirring and dissolving, and filtering after the reaction is completed to obtain a first filtrate; s3, mixing and stirring part of the first filtrate with first ammonia water, and aging to obtain silica gel seed crystals; s4, mixing and stirring the silica gel seed crystal and the residual first filtrate, adding second ammonia water under the stirring condition, continuing stirring to perform ammonolysis reaction until crystallization is completed, and filtering to obtain a silica filter cake and second filtrate; and S5, evaporating and deaminizing the second filtrate, recycling the obtained ammonia gas to the step S3 and/or the step S4, and recycling the obtained ammonium bifluoride to the step S2.
  2. 2. The method for recycling fluorine-containing silicon slag according to claim 1, wherein the concentration of the ammonium bifluoride solution is 17wt.% to 20wt.%.
  3. 3. The recycling method of fluorine-containing silica slag according to claim 1, wherein the weight ratio of the first ammonia water to the first filtrate in the step S3 is 1.6-1.7:1.
  4. 4. The recycling method of fluorine-containing silica slag according to claim 1, wherein the mass fraction of solute in the first ammonia water is 2% -5%.
  5. 5. The recycling method of fluorine-containing silica slag according to claim 1, wherein the weight ratio of the second ammonia water to the first filtrate in the step S4 is 0.27-0.29:1.
  6. 6. The recycling method of fluorine-containing silica slag according to claim 1, wherein the mass fraction of solute in the second ammonia water is 10% -20%.
  7. 7. The recycling method of fluorine-containing silica slag as set forth in claim 1, wherein the first filtrate obtained in the step S3 is 20% -30% of the total mass of the first filtrate.
  8. 8. The recycling method of fluorine-containing silica slag according to claim 1, wherein the stirring speed in the step S3 is 280-320 r/min, and the stirring time is 10-20S.
  9. 9. The recycling method of fluorine-containing silicon slag according to claim 1, wherein the temperature of stirring and aging in the step S3 is 30-55 ℃.
  10. 10. The recycling method of fluorine-containing silicon slag according to claim 1, wherein the stirring speed in the ammonolysis reaction process in the step S4 is 150-250r/min, and the temperature is 40-70 ℃.

Description

Resource utilization method of fluorine-containing silicon slag Technical Field The invention relates to the field of resource utilization of fluorine-containing silicon slag, in particular to a resource utilization method of fluorine-containing silicon slag. Background The fluorosilicate slag is a byproduct generated in the process of generating fluoride products by taking fluosilicic acid or fluosilicate as a raw material, and the main components comprise silicon dioxide, fluosilicic acid, water and the like. The prior recycling utilization of the fluorine-containing silicon slag comprises the step of converting silicon dioxide with low specific surface area in the fluorine-containing silicon slag into white carbon black, wherein the commonly adopted method is to react the fluorine-containing silicon slag with a strong alkaline solution to prepare an alkali metal ion silicate solution, and then react the alkali metal ion silicate solution with acid to prepare the white carbon black. But sulfuric acid has strong corrosiveness, violent reaction and difficult control, hydrochloric acid has strong volatility and corrosiveness, the reaction speed is higher, the particle size and the morphology are difficult to control, the carbonic acid reaction is slow, and the precipitation effect is poor. In addition, the introduction of alkali metal ions not only promotes the aggregation of silica particles by the charge shielding effect or the salt effect, resulting in a decrease in specific surface area, but also the corresponding by-product, alkali metal ion salt, has limited added value. Disclosure of Invention In view of the shortcomings of the related art, the invention provides a resource utilization method of fluorine-containing silicon slag. The invention provides a resource utilization method of fluorine-containing silicon slag, which adopts the following technical scheme: A resource utilization method of fluorine-containing silicon slag comprises the following steps: s1, washing fluorine-containing silicon slag, and filtering to obtain crude silicon dioxide and fluosilicic acid aqueous solution; S2, adding excessive crude silicon dioxide into ammonium bifluoride solution, stirring and dissolving, and filtering after the reaction is completed to obtain a first filtrate; s3, mixing and stirring part of the first filtrate with first ammonia water, and aging to obtain silica gel seed crystals; s4, mixing and stirring the silica gel seed crystal and the residual first filtrate, adding second ammonia water under the stirring condition, continuing stirring to perform ammonolysis reaction until crystallization is completed, and filtering to obtain a silica filter cake and second filtrate; and S5, evaporating and deaminizing the second filtrate, recycling the obtained ammonia gas to the step S3 and/or the step S4, and recycling the obtained ammonium bifluoride to the step S2. According to the scheme, silicon dioxide in the fluorine-containing silicon slag is separated from fluosilicic acid in the step S1, crude silicon dioxide is converted into ammonium fluosilicate aqueous solution (first filtrate) containing fluoride ions through a 4NH 4HF2+SiO2=（NH4）2SiF6+2NH4F+2H2 O reaction in the step S2, ammonia fluosilicate is converted into silicon dioxide gel seed crystal through a (NH 4)2SiF6+4NH3·H2O=SiO2+6NH4F+2H2 O reaction in the step S3, ammonium fluosilicate in the rest first filtrate is crystallized under the induction of the silicon dioxide gel seed crystal in the step S4 to obtain a silicon dioxide filter cake (the purity and specific surface area of silicon dioxide meet the requirements of white carbon black) and second filtrate with the main component of ammonium fluoride aqueous solution, ammonium fluoride in the second filtrate is converted into ammonium bifluoride and ammonia water in the step S5 to be recycled in the step, the fluorine-containing silicon slag is used as a raw material in the whole process route, the raw material source is wide, the white carbon black product is synthesized through the preparation of the seed crystal, the product quality is high, the reaction condition is mild, the comprehensive utilization degree is high, and no secondary waste is generated. Preferably, the concentration of the ammonium bifluoride solution is 17wt.% to 20wt.%. Preferably, the weight ratio of the first ammonia water to the first filtrate in the step S3 is 1.6-1.7:1. Preferably, the weight ratio of the first ammonia water to the first filtrate in the step S3 is 1.68:1. Preferably, the mass fraction of the solute in the first ammonia water is 2% -5%. Preferably, the weight ratio of the second ammonia water to the first filtrate in the step S4 is 0.27-0.29:1. Preferably, the weight ratio of the second ammonia water to the first filtrate in the step S4 is 0.272:1. Preferably, the mass fraction of the solute in the second ammonia water is 10% -20%. Preferably, the first filtrate used in the step S3 accounts for 20% -3