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CN-122004207-A - Method for preparing antibacterial functional core-shell silicon dioxide from fluorine-containing silicon slag

CN122004207ACN 122004207 ACN122004207 ACN 122004207ACN-122004207-A

Abstract

The invention relates to the technical field of chemical industry, in particular to a method for preparing antibacterial functional core-shell silicon dioxide by fluorine-containing silica slag, which comprises the following steps of S1, silica slag pretreatment, namely, mixing silica slag with water to prepare slurry, sanding the slurry, controlling the particle size D50<200nm of SiO 2 in the sanded silica slag, S2, alkali-activated silica release, namely, mixing the sanded slurry with alkali solution, carrying out hydrothermal reaction, and controlling the dissolution rate of the silicon to be in a preset range; S3, constructing a gradient pH core-shell, namely firstly adjusting the pH value of a system to an alkaline zone and reacting to form a compact inner shell, secondly adjusting the pH value of the system to an acidic zone, adding a zinc-fluorine-containing solution to react to form a composite outer shell, and S4, performing post-treatment, namely washing and calcining the product obtained in the step S3 to obtain the antibacterial functional core-shell silica. According to the invention, through four-step integrated processes of pretreatment, activation, gradient coating and post-treatment, the purification of the silicon slag is completed by a one-step method, and the directional conversion of fluorine-containing waste slag into high-added-value functional materials is realized.

Inventors

  • ZHANG WEI
  • BAI JINLI
  • LI YANGHUI
  • Wu Xianye
  • DENG JIALEI
  • LI HUIMIN
  • CHEN XINGRONG
  • XUE YUFENG

Assignees

  • 云南凯威特新材料股份有限公司
  • 福泉凯威特新材料有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag is characterized by comprising the following steps of: S1, preprocessing silicon slag, namely mixing the silicon slag with water to prepare slurry, performing sanding treatment on the slurry, and controlling the grain diameter D50<200nm of SiO 2 in the silicon slag after sanding; S2, alkali-activated silicon release, namely mixing the sanded slurry with an alkali solution, performing a hydrothermal reaction, and controlling the dissolution rate of silicon to be in a preset range; S3, constructing a gradient pH core-shell, namely firstly adjusting the pH value of the system to an alkaline zone and reacting to form a compact inner shell, then adjusting the pH value of the system to an acidic zone, and adding a zinc-fluorine-containing solution to react to form a composite outer shell; and S4, post-treatment, namely washing and calcining the product obtained in the step S3 to obtain the antibacterial functional core-shell silica.
  2. 2. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is disclosed in claim 1, is characterized in that in the step S1, the solid-liquid mass ratio of the silica slag to water is 1:2, the mass ratio of the slurry SiO 2 is 20%, the grinding medium adopted in the sanding is zirconia beads, the particle size of the zirconia beads is 0.05-0.1mm, the rotating speed of a sand mill is 3000r/min, and the sanding time is 4h.
  3. 3. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag according to claim 1, wherein in the step S1, a laser particle sizer is adopted to detect the particle size of SiO 2 after sanding.
  4. 4. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S2, the alkali solution is NaOH solution with the concentration of 1mol/L, and the mass ratio of the sand grinding slurry to the NaOH solution is 1:3.
  5. 5. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S2, the hydrothermal reaction temperature is 120 ℃, the reaction time is 2-3h, and the silicon dissolution rate in the preset range is 18+/-2%.
  6. 6. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag according to claim 1, wherein in the step S3, before the system is regulated to an alkaline interval, a cationic surfactant CTAB is added, and the addition amount is 0.1% of the mass of the dry SiO 2 .
  7. 7. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S3, the pH value of an alkaline zone is 10.5, the pH is regulated by adopting 1mol/L H 2 SO 4 , the reaction temperature of the alkaline zone is 80 ℃, and the reaction time is 3 hours.
  8. 8. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S3, the pH value of the acid zone is 3.5, 1mol/L H 2 SO 4 is adopted to adjust the pH value, the solution containing zinc and fluorine is ZnCl 2 solution, and the Zn/F mol ratio is 1.8:1.
  9. 9. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S3, the slurry is injected into a ZnCl 2 solution at the rate of 5ml/min, the reaction temperature in an acid zone is 40 ℃, and the reaction time is 4 hours.
  10. 10. The method for preparing the antibacterial functional core-shell silica from the fluorine-containing silica slag, which is characterized in that in the step S4, 95% ethanol and water are used for alternately washing the product for 3 times, the volume of each washing liquid is 2 times of the solid volume, the calcining temperature is 550 ℃, and the calcining time is 4 hours.

Description

Method for preparing antibacterial functional core-shell silicon dioxide from fluorine-containing silicon slag Technical Field The invention relates to the technical field of chemical industry, in particular to a method for preparing antibacterial functional core-shell silicon dioxide from fluorine-containing silicon slag. Background Phosphate fertilizer, fluoride chemical by-product waste residue (containing 30-50% of amorphous SiO 2 and 5-15% of fluoride), and the conventional landfill treatment has high risk of fluoride ion dissolution pollution and resource non-utilization. While the prior patent proposes that fluorine is stripped, silica is further treated into white carbon black for utilization, fluorine wastewater is difficult to treat, and the prepared white carbon black has poor performance and has not been popularized. The core-shell silica has unique core-shell structure, has the stability of the core and the functionality of the shell, and has wide application prospect in the fields of catalysis, adsorption, biological medicine, antibacterial materials and the like. The antibacterial functional core-shell silica can realize long-acting antibacterial performance by loading antibacterial active ingredients (such as metal ions of silver, zinc, copper and the like or antibacterial organic matters) on the shell layer, and the core-shell structure can effectively reduce the loss of the antibacterial ingredients and improve the stability and the safety of the material. Limitations of traditional core-shell material preparation: the patent CN118851193A only uses a silicon source to prepare white carbon black, is not functionalized, and has narrow application scene of products; The patent CN106000285A needs to additionally add a silicon source, and has high cost; the patent CN110996885A adopts a metal coating method to prepare the core-shell material, and fluorine elements in the silicon slag are required to be removed in advance, so that the high-value utilization of fluorine is not realized; The gradient coating technique of patent CN115011143a does not solve the problem of harmful component conversion. At present, no technology is available for directly converting fluorine-containing silica slag into functional core-shell silica. The prior art either ignores the functionalization potential of the silicon slag or can not synchronously solve the problems of fluorine pollution and silicon resource low value. The invention creatively utilizes inherent SiO 2 in the silicon slag to construct a core-shell structure, converts fluoride into an antibacterial component ZnF 2, and realizes the integration of waste treatment, resource utilization and high-value product. Disclosure of Invention The invention mainly provides a method for preparing antibacterial functional core-shell silicon dioxide from fluorine-containing silicon slag, which is characterized in that the four-step integrated process of pretreatment, activation, gradient coating and post-treatment is adopted to finish the purification, functionalization and high-value of the silicon slag by one-step method, so that the directional conversion of the fluorine-containing waste slag into a high-value functional material is realized. The technical implementation scheme of the invention is as follows: A method for preparing antibacterial functional core-shell silica from fluorine-containing silica slag comprises the following steps: S1, preprocessing silicon slag, namely mixing the silicon slag with water to prepare slurry, performing sanding treatment on the slurry, and controlling the grain diameter D50<200nm of SiO 2 in the silicon slag after sanding; S2, alkali-activated silicon release, namely mixing the sanded slurry with an alkali solution, performing a hydrothermal reaction, and controlling the dissolution rate of silicon to be in a preset range; S3, constructing a gradient pH core-shell, namely firstly adjusting the pH value of the system to an alkaline zone and reacting to form a compact inner shell, then adjusting the pH value of the system to an acidic zone, and adding a zinc-fluorine-containing solution to react to form a composite outer shell; and S4, post-treatment, namely washing and calcining the product obtained in the step S3 to obtain the antibacterial functional core-shell silica. Preferably, in the step S1, the solid-liquid mass ratio of the silica slag to the water is 1:2, the mass ratio of the slurry SiO 2 is 20%, the grinding medium adopted in the sanding is zirconia beads, the particle size of the zirconia beads is 0.05-0.1mm, the rotating speed of a sand mill is 3000r/min, the sanding time is 4h, and in the step S1, the particle size of SiO 2 after the sanding is detected by a laser particle sizer. In the S1 step, the sand grinding can break agglomerates in the silica slag, the micron-sized particle size is reduced to the nanometer-sized particle size (D50 <200 nm), the uniformity of the size of the inner core can be ensured, une