Search

CN-122007130-A - Red mud roadbed filler based on industrial tail gas acidification regulation and control and preparation method thereof

CN122007130ACN 122007130 ACN122007130 ACN 122007130ACN-122007130-A

Abstract

The invention discloses a red mud roadbed filler based on industrial tail gas acidification regulation and control and a preparation method thereof, and belongs to the technical field of industrial solid waste recycling and road engineering materials. According to the method, after red mud is mixed with a calcium-based solid waste and pollution component curing agent, industrial tail gas at 300-500 ℃ is utilized to carry out gradient acidification under the conditions of specific pressure (0.5-2.0 MPa) and time (1-4 h), and the active design of the grain size grading of an acidification product is realized by accurately regulating and controlling the acidification process parameters, so that the optimum grading curve of roadbed filling is met. Acidic components such as CO 2 、SO 2 、NO x in industrial tail gas react with calcium-based solid waste to generate gelling products such as calcium sulfate and calcium nitrate while desulfurization and denitrification are realized, and the material performance is cooperatively improved. The introduced pollutant component curing agent can specifically adsorb and fix the residual soluble sodium ions and heavy metal ions in the red mud in the acidification process and the later service stage, effectively inhibit the migration of alkali and heavy metal, and simultaneously serve as a nano reinforcing phase to improve the compactness and mechanical property of the material. The optimal water content range of the obtained acidified red mud roadbed filler is 12-18%, the maximum dry density can reach 1.8-2.1g/cm < 3 >, the CBR value is more than 80%, the water stability is more than 0.8, the unconfined compressive strength is more than 1.2MPa, and the leaching concentration of sodium/heavy metal meets the water standard of 'quality standard of groundwater'. Completely meets the requirements of highway subgrade filling technology and environmental protection, and realizes the triple targets of red mud innocuity, tail gas purification and subgrade material production.

Inventors

  • MA CHUANYI
  • TAO MENGMENG
  • ZHANG SHENGTAO
  • LI ZHAOFENG
  • WANG CHUAN
  • ZHANG JIAN
  • LIN CHUNJIN

Assignees

  • 山东高速集团有限公司
  • 山东大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The preparation method of the red mud roadbed filler based on the acidification of industrial tail gas is characterized by comprising the following steps of: Uniformly mixing red mud and calcium-based solid waste and pollution component curing agent according to the mass ratio of 100 (5-15) (0.1-3) to obtain a mixture; acidifying the mixture and industrial tail gas at 300-500 ℃ to obtain an acidified product, wherein the industrial tail gas contains CO 2 、SO 2 and NO x ; crushing and screening the acidified product, and regulating the water content to be 12-18% to obtain the red mud roadbed material.
  2. 2. The method for preparing red mud roadbed filler based on acidification of industrial tail gas according to claim 1, wherein the calcium-based solid waste is carbide slag or granulated blast furnace slag.
  3. 3. The method for preparing red mud roadbed filler based on industrial tail gas acidification according to claim 1, wherein the pollution component curing agent takes iron, aluminum or zirconium as a metal center, and takes terephthalic acid, trimesic acid or 2-methylimidazole as at least one of organic ligands.
  4. 4. The method for preparing red mud roadbed filler based on industrial tail gas acidification according to claim 1, wherein the specific surface area of the pollutant component curing agent is more than 1000m2/g.
  5. 5. The method for preparing red mud roadbed filler based on acidification of industrial tail gas according to claim 1, wherein the industrial tail gas is industrial kiln tail gas of an alumina power plant, the volume concentration of CO 2 is 12-20%, the concentration of SO 2 is 100-4000ppm, and the concentration of NO x is 100-600ppm.
  6. 6. The method for preparing red mud roadbed filler based on industrial tail gas acidification according to claim 1, wherein the pressure of the acidification reaction is 0.5-2.0MPa, and the reaction time is 1-4h.
  7. 7. The method for preparing red mud roadbed filler based on industrial tail gas acidification according to claim 1, wherein the acidification reaction is carried out by adopting a staged pressure-time gradient process and comprises at least two continuous pressure-time stage combinations.
  8. 8. The process for preparing red mud subgrade filler based on the acidification of industrial tail gas according to claim 1, characterized in that the first stage of the acidification reaction is carried out for 1-2 hours at a pressure of 0.5-1.0MPa, the second stage raises the pressure to 1.5-2.0MPa and the reaction is continued for 0.5-2 hours.
  9. 9. The red mud roadbed filler based on acidification of industrial tail gas prepared by the method according to any one of claims 1 to 8, wherein the optimal grading range is 90-100% of 4.75mm sieve pore passing rate, 40-70% of 0.6mm sieve pore passing rate and 10-35% of 0.075mm sieve pore passing rate.
  10. 10. The red mud subgrade filler based on the acidification of industrial tail gas according to claim 9, characterized in that the maximum dry density is 1.8-2.1g/cm3, CBR value is more than 80% and the water swelling ratio is less than 1.5%.

Description

Red mud roadbed filler based on industrial tail gas acidification regulation and control and preparation method thereof Technical Field The invention belongs to the field of industrial solid waste recycling and road engineering, and relates to roadbed filler which is prepared by acidizing red mud by utilizing industrial tail gas, regulating engineering characteristics of the red mud and stabilizing harmful ions for a long time and a preparation method of the roadbed filler. Background The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. Red mud is a large amount of solid waste generated in the industrial production process of alumina, the strong alkalinity of the red mud can form a potential threat to the environment, and the annual emission of the red mud exceeds 1.5 hundred million tons. The main reason for restricting the recycling of the red mud at present is that the method is an effective red mud modification method because of strong alkalinity and carbonation treatment, and stable carbonate is generated by the reaction of CO 2 and alkaline substances in the red mud, so that the pH value of the red mud is reduced and the engineering property is improved. However, the existing carbonation technology has the following defects that (1) pure CO 2 gas is mostly adopted, the cost is high, (2) the carbonation temperature is mostly normal temperature or low temperature, the reaction efficiency is low, and (3) the grain size grading of carbonated products is not effectively regulated, so that the strict requirements of roadbed materials are difficult to meet. Industrial tail gas often contains acidic polluted gases such as SO 2, NOx and the like besides CO 2. The prior art focuses on the carbonation utilization of CO 2, but the research on the synergetic recycling treatment of SO 2 and NOx in tail gas is insufficient. If the acidic component can be used for modifying the red mud, the pH value of the red mud can be reduced more thoroughly, the material performance can be improved by generating a new gel phase (such as calcium sulfate), the low-cost desulfurization and denitrification of the tail gas can be realized, and the method has remarkable environmental and economic benefits. Disclosure of Invention In order to solve the problems, the invention provides a roadbed material which utilizes industrial tail gas containing multiple acidic components to carry out synergistic acidification treatment on red mud, accurately regulate and control the product performance and stabilize harmful ions for a long time and a preparation method thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention provides a preparation method of red mud roadbed filler based on acidification of industrial tail gas, which comprises the following steps: Uniformly mixing red mud and calcium-based solid waste and pollution component curing agent according to the mass ratio of 100 (5-15) (0.1-3) to obtain a mixture; acidifying the mixture and industrial tail gas at 300-500 ℃ to obtain an acidified product, wherein the industrial tail gas contains CO 2、SO2 and NOx; crushing and screening the acidified product, and regulating the water content to be 12-18% to obtain the red mud roadbed material. In a second aspect of the invention, the red mud roadbed filler based on industrial tail gas acidification prepared by the method is provided. Firstly, the abundant calcium source in the calcium-based solid waste is utilized to react with CO 2 in the tail gas to generate calcium carbonate, and meanwhile, the calcium carbonate is efficiently reacted with SO 2 and NOx to generate products such as calcium sulfate and calcium nitrate. The generation of the calcium sulfate not only consumes the oxysulfide in the tail gas, but also is a cementing material, and the calcium sulfate can further react with components such as aluminum, silicon and the like in the system to generate an ettringite and other strength phase, so that the mechanical property of the roadbed material is obviously enhanced while the desulfurization and the denitrification of the tail gas are realized. Second, a contaminant component curing agent of specific function is innovatively introduced. The curing agent has ultrahigh specific surface area and designable functional groups, and can strongly adsorb and fix Na + and heavy metal ions released from the red mud. More importantly, the highly ordered crystal skeleton and regular nano pore canal can be used as an excellent heterogeneous nucleation matrix, a large number of nucleation sites are provided for precipitation crystallization of reaction products such as calcium carbonate and the like, and finer and more uniformly dist