Alkali-activated multi-element solid waste geopolymer gel material and preparation method thereof

Abstract

The invention provides an alkali-activated multi-element solid waste geopolymer gel material and a preparation method thereof, and belongs to the technical field of preparation of alkali-activated inorganic gel materials. The method comprises the steps that the electrolytic manganese residues are dried and ground to the target fineness, calcination pretreatment is conducted, and active electrolytic manganese residues are obtained; carrying out mechanical dry mixing on the obtained active electrolytic manganese residues, superfine slag powder and low-calcium fly ash or barium residues according to a preset mass ratio to obtain a homogeneous composite solid admixture; dissolving sodium hydroxide and ultrapure water according to a designed molar concentration, and cooling the solution to room temperature to prepare an alkaline activator solution; mixing and stirring the obtained composite solid admixture and the alkaline activator solution according to a designed mass ratio in a planetary stirrer to form uniform geopolymer precursor slurry; injecting the precursor slurry into a mold, curing, demolding, and performing standard curing to finally obtain the geopolymer gel material. The cementing material reduces the cost and can be widely applied to the building industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alkali-activated inorganic cementitious materials, in particular to an alkali-activated multi-solid waste geopolymer gel material and a preparation method thereof. BACKGROUND

[0002] The vigorous development of modern industry is highly dependent on important resources such as manganese, and its development and utilization has strongly supported steel smelting and many key fields. However, this growth is also accompanied by the generation of a large amount of industrial solid waste, especially electrolytic manganese residue, blast furnace slag, low-calcium fly ash, and barium residue, and the treatment problem is increasingly serious. At present, the disposal of these solid wastes still generally adopts a simple open-air stacking method, which is low in cost, but in the long run, it poses a great threat to the ecological environment and public health. The stacking of electrolytic manganese residue can seriously pollute the surrounding air, water, and soil; the lead, cadmium, chromium, and other heavy metal elements contained in blast furnace slag may harm human health through the respiratory tract and increase the potential risk of cancer; and the barium ions in barium residue have significant biological toxicity and may cause physiological disorders. These improper treatment methods not only occupy a large amount of land resources, but also have the long-term risk of polluting groundwater, making the environmental cost of industrial development increasingly high.

[0003] At the same time, in the field of material application, traditional cement, as the most important inorganic cementitious material, although widely used, has the disadvantages of high energy consumption and high pollution in the production process, and its products have inherent defects in freeze-thaw resistance, heat resistance, and long-term volume stability. To solve the above-mentioned contradictions, developing new green and high-performance cementitious materials to replace traditional cement has become an important direction in the field of material science.

[0004] Under this background, geopolymer technology shows great potential because of its environmentally friendly preparation process, low energy consumption and carbon emissions, and the product has excellent mechanical properties and durability, providing a promising solution for large-scale resource utilization of industrial solid waste. However, how to develop a geopolymer preparation technology with low activation temperature, short process flow, more optimal energy consumption, and stable material performance for specific solid wastes such as electrolytic manganese residue, is still a key problem to be solved. SUMMARY

[0005] The technology aims to solve the deficiencies of the prior art in resource utilization, and provides an innovative solution for treating these industrial solid wastes by forming a multi-geopolymer under the condition of alkali activation with active electrolytic manganese residue, slag, low-calcium fly ash and barium residue as raw materials. This method not only realizes the harmless treatment of electrolytic manganese residue, slag, low-calcium fly ash and barium residue, but also significantly reduces the calcination temperature, thereby greatly reducing energy consumption. At the same time, the process flow of the present application is simplified, the production cycle is shortened, and large-scale production is easy to realize. In terms of application, the inorganic cementing material obtained by the technology can be widely used in the field of building, which can not only be used as a substitute for cement, but also be suitable for related uses of coating materials. In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A preparation method of an alkali-activated multi-solid waste geopolymer gel material, comprising the following steps: Raw material preparation stage: S1: The electrolytic manganese residue is dried and ground to a target fineness, and then calcined and pretreated at a temperature of 200-1000℃ to obtain active electrolytic manganese residue, and the activity of the active electrolytic manganese residue is analyzed to obtain the highest activity temperature point; S2: The active electrolytic manganese residue, slag powder and low-calcium fly ash or barium residue obtained in step S1 are mechanically dry-mixed according to a predetermined mass ratio, and homogenized to obtain a homogeneous composite solid admixture; S3: Analytical pure sodium hydroxide reagent and ultrapure water are chemically dissolved in a constant-temperature magnetic stirrer according to a designed mass concentration, and after the solution temperature naturally decreases to room temperature (25±2℃), an alkaline activator solution is prepared; Solidification stage: S4: The composite solid admixture obtained in step S2 and the alkaline activator solution obtained in step S3 are mixed and stirred in a planetary mixer according to a designed mass ratio to form a uniform multi-geopolymer precursor slurry; S5: The precursor slurry obtained in step S4 is injected into a mold and solidified at a constant temperature of 20-30℃ for 12-24 hours, and after demolding, standard curing is carried out in a humidity-controlled environment for 3-60 days, to finally obtain a geopolymer gel material with active electrolytic manganese residue, slag, low-calcium fly ash or barium residue as basic raw materials.

[0006] Preferably, in step S1, the electrolytic manganese residue, slag powder, low-calcium fly ash or barium residue is ground to a particle size range of 10-150μm; and the calcination pretreatment temperature of the electrolytic manganese residue is 800℃.

[0007] Preferably, in step S2, the mass ratio of the active electrolytic manganese residue, slag powder and low-calcium fly ash or barium residue is 50:10-40:10-40.

[0008] Preferably, in step S3, the amount of sodium hydroxide added is 4%-6.6% of the total mass of the dry substance mixture.

[0009] Preferably, in step S4, the mass ratio of the composite solid admixture to the alkaline activator solution is 1:0.3 to 1:0.5.

[0010] Preferably, in step S4, the stirring time in the planetary mixer is 3-8 minutes.

[0011] Preferably, in step S5, the specific conditions of the standard curing are that the 28-day compressive strength of the geopolymer gel material is not less than 21.17 MPa when the curing age is 28 days.

[0012] Preferably, in step S5, the standard curing is carried out in a standard mortar curing box.

[0013] Another technical solution of the present application is an alkali-activated multi-solid waste geopolymer gel material prepared by the above-mentioned method for preparing an alkali-activated multi-solid waste geopolymer gel material.

[0014] In order to achieve the purpose of the present application, the present application also provides an application of an alkali-activated multi-solid waste geopolymer gel material, which is used in the construction industry to replace or supplement aluminosilicate cement, or used to prepare coating materials Compared with the prior art, the present application achieves the following technical effects: The present application develops a new type of environmentally friendly inorganic cementing material by utilizing and harmless treating active electrolytic manganese slag, slag, and low-calcium fly ash / barium slag, which can be widely used in the construction industry to reduce costs and meet the needs of specific scenarios. Compared with traditional methods, the calcination temperature is lower, significantly reducing energy consumption, and the preparation process is simple and efficient, easy to realize large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0015] For ease of illustration, the present application is described in detail by the following specific embodiments and drawings.

[0016] Figure 1 The test results related to Example 1 are shown in the following figures. The left upper figure is an XRD graph, the left lower figure is a SEM graph at 2 microns, the right upper figure is a TG-DCS graph, and the right lower figure is a SEM graph at 500 nanometers.

[0017] Figure 2The figure is the test result of the example 2. It is the result figure of the 28d of the calcined electrolytic manganese residue, slag, barium residue after alkali activation. The upper left figure is the XRD figure, the lower left is the SEM figure of 2pm, the upper right is the TG-DCS figure, and the lower right is the SEM figure of 500nm. DETAILED DESCRIPTION

[0018] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in conjunction with the drawings, but the present application is not limited to these embodiments; in the following description, specific details such as specific configurations are provided only to help a comprehensive understanding of the embodiments of the present application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application.

[0019] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0020] The materials, practices and experimental equipment involved in the embodiments of the present application, if not specifically stated, are consistent with the commercially available products in the relevant chemical and biotechnology fields.

[0021] Example 1: An alkali-activated multi-solid waste geopolymer gel material and a preparation method thereof, the steps are as follows: Raw material preparation stage: S1: Dry the initial raw materials electrolytic manganese residue, slag, and low-calcium fly ash, and then crush them to a particle size of 23pm through a grinding device. The ground electrolytic manganese residue is placed in a high-temperature environment of 800℃ for calcination pretreatment, and finally the pretreated electrolytic manganese residue is obtained; S2: The pretreated active electrolytic manganese residue, slag, and low-calcium fly ash obtained in step S1 are mixed uniformly according to a mass ratio of 5:3:2 with slag to prepare solid ash; S3: Dissolve sodium hydroxide in deionized water according to a mass fraction of 4.5% to prepare an alkali activator solution; Solidification stage: S4: Mix the solid ash obtained in step S1 with the alkali activator solution prepared in step S2 according to a mass ratio of 1:0.40, and continuously stir for 5 minutes, to finally form a geopolymer slurry; S5: Place the prepared geopolymer slurry in step S3 in an environment of 20℃ for solidification treatment, and after 12 hours, finally obtain the electrolytic manganese residue calcined slag, low-calcium fly ash, and slag geopolymer cementitious material.

[0022] Place the electrolytic manganese residue calcined slag, low-calcium fly ash, and slag geopolymer cementitious material prepared in the above steps into a standard mortar curing box for curing.

[0023] The micro-morphology of the electrolytic manganese residue calcined slag, low calcium fly ash and slag-based geopolymer cementitious material was observed for the experiment, and the equipment used was SU8010 field emission scanning electron microscope manufactured by Japan Hitachi Company; the evaluation of the mechanical properties was completed by means of CTM8050 microcomputer-controlled electronic universal testing machine; for the determination of the mineral composition, D8 ADVANCE X-ray diffractometer produced by Germany Bruker AXS Company was adopted, and the specific parameters were current 40 mA, voltage 40 kV, and CuKα radiation source was used; the results of XRD and scanning electron microscope are shown in Figure 1 The mechanical property test results show that the 3-day compressive strength of the material is 15.47 MPa, the 7-day strength is increased to 18.51 MPa, and the 28-day strength is further increased to 32.29 MPa.

[0024] Figure 1 The XRD of the electrolytic manganese residue calcined slag, slag and fly ash points out that the hydration products of the 28 d hydration age are mainly AFt (Ca6Al2(SO4)2(OH) 12 ·26H2O), CaSO4·2H2O, calcite, (C,N)-S-A-H gel (CaAl2Si3O, NaAlSi2O6, etc.), which is rich in siliceous and aluminous minerals in the system, and these active siliceous and aluminous clay minerals are preferentially dissolved in OH - solution, generating a large amount of [Al(OH)4] - , [SiO2(OH)2] 2- ions, when the ion concentration reaches the critical nucleation concentration of the gel, the ions re-polymerize into crystalline materials with Si-O-Al network structure, and continue to grow and harden, while the metal cations Na + , Ca 2+ participate in the charge balance of Al 3+ , and finally form a geopolymer gel mainly in the form of ionic and covalent bonds supplemented by van der Waals forces. In the SEM diagram, there are regular hexagonal prismatic CaSO4·2H2O crystals, needle-like AFt, honeycomb-shaped dense C(N)-A-S-H gel, and the geopolymer gel grows on the surface of the crystal phase and fills the interstices to reduce the distribution of interstices, which together constitute the source of the strength of the geopolymer gel.

[0025] Example 2: An alkali-activated multi-component solid waste geopolymer gel material and a preparation method thereof, the steps are as follows: Raw material preparation stage: S1: First, the raw materials of electrolytic manganese residue, slag and barium residue are dried, and then ground to a particle size of 23 μm. The ground electrolytic manganese residue is calcined at 800°C to obtain treated electrolytic manganese residue; S2: The pre-treated active electrolytic manganese residue, slag and barium residue in step S1 are mixed in a mass ratio of 5:2:3 to prepare a uniform solid ash; S3: Sodium hydroxide is dissolved in deionized water at a mass fraction of 5% to prepare an alkali activator solution; Curing stage: S4: The solid ash obtained in step S1 is mixed with the alkali activator solution prepared in step S2 in a mass ratio of 1:0.42, and stirred for 5 minutes to form a geopolymer slurry; S5: The geopolymer slurry prepared in step S3 is cured at a temperature of 20°C for 12 hours to form an active electrolytic manganese residue, slag and barium residue geopolymer cementitious material.

[0026] The active electrolytic manganese residue, slag and barium residue geopolymer cementitious material prepared in the above steps is placed in a standard mortar curing box for curing.

[0027] The microstructure of the active electrolytic manganese residue, slag and barium residue geopolymer cementitious material prepared in the above steps is observed. The equipment used is a SU8010 field emission scanning electron microscope manufactured by Hitachi, Japan. The mechanical properties are evaluated by a CTM8050 microcomputer-controlled electronic universal testing machine. The mineral composition is determined by a D8 ADVANCE X-ray diffractometer manufactured by Bruker AXS, Germany, with specific parameters of current 40 mA, voltage 40 kV, and CuKα radiation source. The relevant test data show that the results of XRD and scanning electron microscopy are as shown in Figure 2 The mechanical property test results show that the 3-day compressive strength of the material is 4.64 MPa, the 7-day strength increases to 9.34 MPa, and the 28-day strength further increases to 21.17 MPa.

[0028] Figure 2The XRD diagram of the electrolytic manganese residue calcined residue, slag, barium residue, and hydrated 28 d age indicates that Ca(Al2Si2O8), Al2(SiO4)(OH)2, CaSO4·2H2O, and other crystal phases are generated, and the peaks of BaSO4 and BaCO3 cannot be observed in the system, because the silicate and aluminate in the barium residue exist in an amorphous form, and a large amount of the silicate and aluminate participate in the generation of the geopolymer gel in the alkali excitation process, and the generated crystal phases grow on the surface and play a wrapping role. The SEM diagram indicates that a large amount of CaSO4·2H2O in the form of plate and needle, and fibrous calcite crystals, and flocculent and sponge-like C(N)-A-S-H gel with a relatively dispersed distribution are generated, the geopolymer gel grows with BaSO4 and BaCO3 as the attachment points and wraps them, the crystal phases in the system are interwoven, and the gel is filled in the pores, which constitutes the source of the strength of the geopolymer system.

[0029] Those skilled in the art to which the present application pertains can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace them, without departing from the inventive concept of the present application or exceeding the scope defined by the appended claims.

Claims

1. A method of producing an alkali-activated, multi-waste geological polymer gel material, characterized by, The method comprises the following steps: A raw material preparation stage: S1: drying and grinding electrolytic manganese residue to a target fineness, and then calcining and pretreating the electrolytic manganese residue at a temperature in the range of 200-1000℃ to obtain active electrolytic manganese residue; S2: mechanically dry mixing the active electrolytic manganese residue obtained in step S1, slag powder, and low-calcium fly ash or barium residue in a preset mass ratio to obtain a homogeneous composite solid admixture; S3: dissolving sodium hydroxide and ultrapure water in a designed molar concentration, and preparing an alkaline activator solution after the solution is cooled to room temperature; A curing stage: S4: mixing and stirring the composite solid admixture obtained in step S2 and the alkaline activator solution obtained in step S3 in a planetary mixer in a designed mass ratio to form a uniform geopolymer precursor slurry; S5: injecting the precursor slurry obtained in step S4 into a mold, curing for 12-24 hours under constant temperature conditions of 20-30℃, and performing standard curing for 3-60 days in a humidity-controlled environment after demolding to finally prepare the geopolymer gel material.

2. The production method according to claim 1, characterized by, In step S1, the electrolytic manganese residue, slag powder, low-calcium fly ash, or barium residue is ground to a particle size range of 10-150μm; and the calcination pretreatment temperature of the electrolytic manganese residue is 800℃.

3. The production method according to claim 1, characterized by, In step S2, the mass ratio of the active electrolytic manganese residue, slag powder, and low-calcium fly ash or barium residue is in the range of 50:10-40:10-40.

4. The method of claim 1, wherein, In step S3, the addition amount of sodium hydroxide, in terms of the percentage of the mass of sodium hydroxide to the total mass of dry material mixture, is 4%-6.6%.

5. The preparation method according to claim 1, characterized in that, In step S4, the mass ratio of the composite solid admixture to the alkaline activator solution is 1:0.3 to 1:0.

5.

6. The method of claim 1, wherein, In step S4, the stirring time in the planetary mixer is 3-8 minutes.

7. The preparation method according to claim 1, characterized in that, In step S5, the specific conditions of the standard curing are that the 28-day compressive strength of the geopolymer gel material is not less than 21.17 MPa when the curing age is 28 days.

8. The method of claim 1, wherein, In step S5, the standard curing is performed in a standard mortar curing box.

9. An alkali-activated multi-component solid waste geopolymer gel material prepared by the preparation method of any one of claims 1 to 8.

10. Use of an alkali-activated, multiplexed solid waste geopolymer gel material as claimed in claim 9, characterised in that, The material is used in the construction industry to replace or supplement aluminosilicate cement, or to prepare coating materials.

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