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CN-121850425-B - Magnesium slag-based aggregate and preparation method thereof

CN121850425BCN 121850425 BCN121850425 BCN 121850425BCN-121850425-B

Abstract

The invention relates to the technical field of solid waste recycling and building materials, in particular to a magnesium slag-based aggregate and a preparation method thereof. The specific technical scheme is that the method comprises the steps of grinding industrial magnesium slag powder into powder, carrying out surface activation and organic-inorganic hybrid coating modification on waste tire rubber powder, grading and mixing the magnesium slag powder, the modified rubber powder and a chemical foaming agent to obtain a composite dry material, mixing the composite dry material with a special bio-based composite cementing solution for granulation, and finally, placing raw material balls in an alkaline carbon dioxide-rich atmosphere for low-temperature carbonization maintenance. The bio-based cementing solution realizes stable solidification through mechanisms such as ionic crosslinking, mineralization induction, organic-inorganic network interpenetrating and the like. The obtained aggregate has a 'compact shell layer' structure, the stacking density is 650-850kg/m 3 , the barrel pressure strength is 6-12MPa, the water absorption is lower than 10%, the impact toughness is excellent, the efficient cooperative utilization of various solid wastes is realized, the process does not need high-temperature sintering, and the low carbon and energy conservation are realized.

Inventors

  • WANG ANHUI
  • HUANG JIAN
  • GUO FEI
  • DUAN WEI
  • LUO RUPING
  • BI YUZHANG

Assignees

  • 黄山学院

Dates

Publication Date
20260508
Application Date
20260317

Claims (8)

  1. 1. The preparation method of the magnesium slag-based aggregate is characterized by comprising the following steps: S1, grading and mixing magnesium slag powder, modified rubber powder and a chemical foaming agent to obtain a composite dry material; s2, mixing and granulating the composite dry material and a bio-based composite cementing solution to form raw material balls, wherein the bio-based composite cementing solution is an organic-inorganic composite solution; S3, placing the raw material balls in a carbon dioxide-rich atmosphere in an alkaline environment for carbonization treatment to obtain light high-strength high-toughness aggregate; the modified rubber powder is prepared by the following steps: S11, placing rubber powder into a sodium hydroxide solution, treating for 30-60min at 40-60 ℃, cleaning and drying; S22, immersing the rubber micro powder treated by the step S11 into an aqueous solution containing tannic acid and calcium lignosulfonate for adsorption treatment, and carrying out ultrasonic oscillation dispersion under the condition of 40-60 ℃ for reaction for 30-90min; S33, after the step S22 is completed, separating and removing supernatant, dispersing the obtained wet-state rubber micropowder into MgCl 2 solution with the concentration of 0.2-0.3mol/L, continuously stirring, regulating the pH to 8.5-9.5, and continuing the reaction; s44, after the reaction is finished, carrying out solid-liquid separation on the product, and sequentially washing and drying to obtain the modified rubber micro powder; the bio-based composite cementitious solution is prepared by the following method: P1, standing and curing a xanthan gum solution, a guar gum solution and an aspartic acid solution at room temperature, then mixing and stirring to form a uniform ternary composite solution; p2, uniformly mixing mineral powder and carbide slag powder to obtain composite inorganic powder; P3, adding the composite inorganic powder obtained in the step P2 into a ternary composite solution, and adopting the steps of soaking at 200-300rpm and shearing and dispersing at 1000-2000rpm, and continuously treating for 20-30min to obtain homogeneous and stable suspension composite slurry; P4, dispersing the composite slurry prepared in the step P3 into uniform liquid drops with the particle size ranging from 100 mu m to 200 mu m; And P5, dispersing the liquid drop obtained in the step P4 into MgCl 2 solution with the concentration of 0.1-0.15mol/L, and stirring to form the bio-based composite cementing solution.
  2. 2. The preparation method of claim 1, wherein in the step S1, 100 parts of magnesium slag powder, 5-15 parts of modified rubber powder and 0.5-2.0 parts of chemical foaming agent are calculated according to the dry weight parts.
  3. 3. The preparation method of the metal foam plastic material according to claim 1 or 2, wherein in the step S1, the chemical foaming agent is a compound of solid hydrogen peroxide and aluminum powder, and the mixing amount of the aluminum powder is 30% -40% of the total mass of the chemical foaming agent.
  4. 4. The method according to claim 1, wherein in the step S2, the mixing mass ratio of the composite dry material to the bio-based composite cementing solution is 1:0.3-0.5.
  5. 5. The preparation method according to claim 1, wherein in the step S3, the alkaline environment is an atomized alkaline environment or an alkaline solution environment with a pH value of 9-11, and the carbonization treatment is carried out under the condition that the concentration of carbon dioxide is not lower than 20%, the temperature is 50+/-5 ℃, and the treatment time is 48-72 hours.
  6. 6. The method according to claim 1, wherein in the step S22, the mass ratio of tannic acid to calcium lignosulfonate in the aqueous solution is 1:0.5-1.0, and the total mass concentration of the tannic acid and the calcium lignosulfonate is 1.0% -3.0%.
  7. 7. The preparation method of the magnesium-zinc composite material is characterized in that in the step P1, the volume ratio of the xanthan gum solution to the guar gum solution to the aspartic acid solution is 1:0.5-1.0:0.2-0.5, in the step P2, the mass ratio of the mineral powder to the carbide slag powder is 1:0.2-0.5, in the step P3, the composite inorganic powder is 10-15% of the total mass of the ternary composite solution, and in the step P5, the molar ratio of magnesium ions to aspartic acid in a system is controlled to be 1:0.5-1.0.
  8. 8. The magnesium slag-based aggregate prepared by the preparation method of any one of claims 1 to 7, which is characterized by having a continuous pore structure, wrapping a dense mineralized shell layer with a thickness of 2 to 5mm on the outer surface of the aggregate, wherein the aggregate has a bulk density of 650 to 850kg/m 3 , a barrel pressure strength of 6 to 12MPa and a water absorption of less than 10%, and the aggregate has a strength retention rate of not less than 90% after being soaked in water for 28d and an impact toughness index of not less than 15 times.

Description

Magnesium slag-based aggregate and preparation method thereof Technical Field The invention relates to the technical field of solid waste recycling and building materials, in particular to a magnesium slag-based aggregate and a preparation method thereof. Background The industrial magnesium slag is waste slag generated in the smelting process of magnesium metal, is rich in calcium oxide and active magnesium components, has certain gelling activity, but has the problems of slow hydration, poor volume stability and the like, and restricts the large-scale high-value utilization of the industrial magnesium slag. At present, magnesium slag is mainly used for cement mixed materials, roadbed materials or baking-free bricks and other low-added-value products. The lightweight aggregate can lighten the dead weight of concrete and improve the heat preservation performance. The traditional artificial ceramsite (such as shale ceramsite and clay ceramsite) needs high-temperature sintering at 1100-1300 ℃, has high energy consumption and carbon emission, and the fly ash ceramsite can utilize solid waste, but has the defects of low strength, high water absorption and the like. Rubber particles are often used to improve the toughness of building materials, but unmodified rubber powders are inert, hydrophobic on the surface, and weakly bonded to the inorganic gel matrix interface, and direct incorporation tends to result in a significant decrease in strength. The existing chemical modification method (such as silane coupling agent) has high cost, complex process and difficult cooperation with the green mineralization process. Therefore, the development of the lightweight high-strength high-toughness aggregate which can cooperatively utilize magnesium slag and waste tire rubber, has low carbon technology and excellent product performance becomes a technical problem to be solved in the fields of building materials and solid waste recycling. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a magnesium slag-based aggregate and a preparation method thereof, and the method solves the problem of weak interface bonding of a rubber-inorganic matrix through the cooperation of rubber powder interface modification, bio-based composite cementing and alkaline carbonization processes, realizes the regulation and control of magnesium carbonate/calcium carbonate crystal forms, and prepares the lightweight aggregate with excellent comprehensive performance. In order to achieve the above purpose, the invention is realized by the following technical scheme: The invention discloses a preparation method of magnesium slag-based aggregate, which comprises the following steps: S1, grading and mixing magnesium slag powder, modified rubber powder and a physical foaming agent to obtain a composite dry material; S2, mixing the composite dry material with a bio-based composite cementing solution, and granulating to form raw material balls, wherein the bio-based composite cementing solution is an organic-inorganic composite solution; And S3, placing the raw material balls in a carbon dioxide-rich atmosphere in an alkaline environment for carbonization treatment to obtain the light-weight high-strength high-toughness aggregate. Preferably, in the step S1, the magnesium slag powder is 100 parts, the modified rubber powder is 5-15 parts and the chemical foaming agent is 0.5-2.0 parts in terms of dry basis weight parts. Preferably, in step S1, the chemical foaming agent is a compound of solid hydrogen peroxide and aluminum powder, wherein the mixing amount of the aluminum powder is 30% -40% of the total mass of the chemical foaming agent. Preferably, in the step S2, the mixing mass ratio of the composite dry material to the bio-based composite cementing solution is 1:0.3-0.5. Preferably, in the step S3, the alkaline environment is an atomization alkaline environment or an alkaline solution environment with the pH value of 9-11, and the carbonization treatment condition is that the carbon dioxide concentration is not lower than 20%, the temperature is 50+/-5 ℃, and the treatment time is 48-72h. Preferably, the modified rubber powder is prepared by the following method: S11, placing rubber powder into a sodium hydroxide solution, treating for 30-60min at 40-60 ℃, cleaning and drying; S22, immersing the rubber micro powder treated by the step S11 into an aqueous solution containing tannic acid and calcium lignosulfonate for adsorption treatment, and carrying out ultrasonic oscillation dispersion under the condition of 40-60 ℃ for reaction for 30-90min; S33, after the step S22 is completed, separating and removing supernatant, dispersing the obtained wet-state rubber micropowder into MgCl 2 solution with the concentration of 0.2-0.3mol/L, continuously stirring, regulating the pH to 8.5-9.5, and continuing the reaction; and S44, after the reaction is finished, carrying out solid-liquid separation on the product, and washing and