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CN-122010624-A - Preparation method for preparing soil remediation matrix by synergistic activation of coal-based solid wastes

CN122010624ACN 122010624 ACN122010624 ACN 122010624ACN-122010624-A

Abstract

The invention discloses a preparation method for preparing a soil remediation matrix by synergistic activation of coal-based solid wastes, and belongs to the technical field of recycling of coal chemical solid wastes and soil remediation. According to the invention, a four-element synergistic system of coal ash, coal gangue, desulfurized gypsum and biomass charcoal is constructed, and a soil remediation matrix with dual functions of heavy metal resistance control and nutrient regulation is constructed by combining coal gangue step thermal activation, coal ash mechanochemical modification and desulfurized gypsum carbonate chemical conversion technology and agricultural wastes to prepare functionalized biomass charcoal. The method has stable process, the prepared matrix can obviously improve the pH value of the acid soil, effectively reduce the bioavailability of heavy metals, increase the organic matter content of the soil, provide nutrients and is suitable for repairing and improving large-area polluted soil.

Inventors

  • Cao Yinnan
  • LI ZHI
  • WANG QINGGANG
  • TAO PENGFEI
  • CHEN HONGYU
  • HU JIAJUN
  • ZHANG CHU

Assignees

  • 平安煤炭开采工程技术研究院有限责任公司
  • 安徽理工大学

Dates

Publication Date
20260512
Application Date
20260225

Claims (10)

  1. 1. The method for preparing the soil remediation matrix by the synergistic activation of the coal-based solid wastes is characterized by comprising the following steps of: After pyrolysis and carbonization of agricultural wastes, chemical activation and modifier solution impregnation are carried out, and activation heat treatment is carried out, so that functionalized biomass charcoal is obtained; After thermally activating the coal gangue, leaching the coal gangue by using an organic acid solution to obtain activated coal gangue rich in active aluminum ions; mixing the fly ash with alkali liquor, and carrying out mechanochemical modification by vibration, stirring or ultrasonic to obtain chemically modified fly ash with improved specific surface area and surface activity; carrying out chemical conversion reaction on the desulfurized gypsum and a carbonate solution to generate a desulfurized gypsum conversion product mainly containing calcium carbonate; And uniformly mixing the functionalized biomass charcoal, the activated coal gangue, the chemically modified fly ash and the desulfurized gypsum conversion product, granulating and drying to obtain the soil remediation matrix.
  2. 2. The method of claim 1, wherein the specific preparation steps of the functionalized biomass charcoal comprise pyrolysis of agricultural waste at 500-700 ℃ for 60-120 min under inert atmosphere to obtain crude biomass charcoal, immersing the crude biomass charcoal in 10-15% by mass of chemical activation and modifier solution for 12-24 h, solid-liquid separation after immersion, carrying out activation heat treatment on the obtained solid at 450-550 ℃ for 30-60 min under inert atmosphere, and finally washing, drying and crushing to obtain the functionalized biomass charcoal, wherein the chemical activation and modifier is diammonium hydrogen phosphate or monoammonium hydrogen phosphate.
  3. 3. The method according to claim 2, wherein the mass ratio of the crude biomass charcoal and the chemical activation to modifier is 1 (8-12).
  4. 4. The method of claim 1, wherein the temperature of the thermal activation is 650-850 ℃.
  5. 5. The method of claim 1, wherein the organic acid solution comprises a solution of citric acid, oxalic acid or tartaric acid, the concentration of the organic acid solution is 0.2-1 mol/L, the mass ratio of the coal gangue to the organic acid solution is 1:5, and the leaching treatment time is 2-6 hours.
  6. 6. The method according to claim 1, wherein the alkali liquor is sodium hydroxide or potassium hydroxide solution with the mass concentration of 1-10%, the mass ratio of the fly ash to the alkali liquor is 1:3, and the mechanochemical modification time is 45min.
  7. 7. The method of claim 1, wherein the carbonate solution is a sodium carbonate solution or an ammonium carbonate solution, the concentration of the carbonate solution is 0.8-1.2 mol/L, the mass ratio of the desulfurized gypsum to the carbonate solution is 1 (8-12), the temperature of the chemical conversion reaction is 50-70 ℃ and the time is 2-4 hours.
  8. 8. The method of claim 1, wherein the mass ratio of the chemically modified fly ash, the activated coal gangue, the desulfurized gypsum conversion product and the functionalized biomass charcoal is (4-5): 3-4): 1-1.5): 0.5-1.
  9. 9. The soil remediation matrix prepared by the method of any one of claims 1-8.
  10. 10. Use of the soil remediation matrix of claim 9 to remediate and improve acidic and heavy metal contaminated soil.

Description

Preparation method for preparing soil remediation matrix by synergistic activation of coal-based solid wastes Technical Field The invention belongs to the technical field of recycling of solid wastes in coal chemical industry and soil remediation, and particularly relates to a preparation method for preparing a soil remediation matrix by synergistic activation of coal-based solid wastes. Background The coal chemical process produces a large amount of solid wastes such as fly ash, coal gangue, desulfurized gypsum and the like, and the traditional stacking mode occupies land and is easy to cause environmental pollution. In addition, the existing soil restoration materials mostly depend on natural minerals or chemical products, and are high in cost, single in function, and insufficient in long-term stability and nutrient retaining capacity for heavy metals. Based on this, the present invention has been proposed. Disclosure of Invention The invention aims to provide a preparation method for preparing a soil remediation matrix by synergistic activation of coal-based solid wastes, so as to solve the problems in the prior art. The method for preparing the soil remediation matrix by using the coal-based solid waste and the agricultural waste as main raw materials through multi-process collaborative activation realizes the dual purposes of solid waste recycling and soil remediation, and the prepared matrix has the functions of effective state inhibition and control of heavy metals and nutrient regulation and control, and has stable process and low cost. In order to achieve the above object, the present invention provides the following solutions: the invention provides a method for preparing a soil remediation matrix by synergistic activation of coal-based solid wastes, which comprises the following steps: after pyrolysis and carbonization of agricultural wastes, chemical activation and modifier solution are used for dipping and activation heat treatment are carried out, so that functionalized biomass charcoal is obtained, and a phosphorus source and a nitrogen source are provided; After thermally activating the coal gangue, leaching the coal gangue by using an organic acid solution to obtain activated coal gangue rich in active aluminum ions; mixing the fly ash with alkali liquor, and carrying out mechanochemical modification by vibration, stirring or ultrasonic to obtain chemically modified fly ash with improved specific surface area and surface activity; carrying out chemical conversion reaction on the desulfurized gypsum and a carbonate solution to generate a desulfurized gypsum conversion product mainly containing calcium carbonate; And uniformly mixing the obtained functionalized biomass charcoal, activated coal gangue, chemically modified fly ash and desulfurized gypsum conversion products, granulating, and drying to obtain the soil remediation matrix. The preparation method of the functionalized biomass charcoal comprises the steps of pyrolyzing agricultural wastes at 500-700 ℃ for 60-120 min under inert atmosphere to obtain crude biomass charcoal, immersing the crude biomass charcoal in a chemical activation and modifier solution with the mass concentration of 10-15% for 12-24 h, carrying out solid-liquid separation after immersion, carrying out activation heat treatment on the obtained solid at 450-550 ℃ for 30-60 min under inert atmosphere, and finally washing, drying and crushing to obtain the functionalized biomass charcoal, wherein the chemical activation and modifier is diammonium hydrogen phosphate or monoammonium hydrogen phosphate. Preferably, the mass ratio of the crude biomass charcoal to the chemical activation and modifier is 1 (8-12). Preferably, the temperature of the thermal activation is 650-850 ℃. Preferably, the organic acid solution comprises a solution of citric acid, oxalic acid or tartaric acid, the concentration of the organic acid solution is 0.2-1 mol/L, the mass ratio of the coal gangue to the organic acid solution is 1:5, and the leaching treatment time is 2-6 hours. Preferably, the alkali liquor is sodium hydroxide or potassium hydroxide solution with the mass concentration of 1-10%, the mass ratio of the fly ash to the alkali liquor is 1:3, and the mechanochemical modification time is 45min. Preferably, the carbonate solution is sodium carbonate solution or ammonium carbonate solution, the concentration of the carbonate solution is 0.8-1.2 mol/L, the mass ratio of the desulfurized gypsum to the carbonate solution is 1 (8-12), the temperature of the chemical conversion reaction is 50-70 ℃ and the time is 2-4 hours. Preferably, the mass ratio of the chemical modified fly ash to the activated coal gangue to the desulfurized gypsum conversion product to the functionalized biomass charcoal is (4-5), 3-4, 1-1.5 and 0.5-1. The second technical scheme of the invention is to provide the soil restoration matrix prepared by the method. The third technical scheme of the invention provides a