CN108439831B - Excitant and red mud fly ash cementing material - Google Patents

Excitant and red mud fly ash cementing material Download PDF

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CN108439831B
CN108439831B CN201810089319.4A CN201810089319A CN108439831B CN 108439831 B CN108439831 B CN 108439831B CN 201810089319 A CN201810089319 A CN 201810089319A CN 108439831 B CN108439831 B CN 108439831B
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red mud
fly ash
excitant
cementing material
cement
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CN108439831A (en
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陈伟
杨腾飞
陈潇
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Wuhan University of Technology WUT
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Wuhan University of Technology WUT
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00Hydraulic cements
    • C04B7/24Cements from oil shales, residues or waste other than slag
    • C04B7/243Mixtures thereof with activators or composition-correcting additives, e.g. mixtures of fly ash and alkali activators
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B12/00Cements not provided for in groups C04B7/00 - C04B11/00
    • C04B12/005Geopolymer cements, e.g. reaction products of aluminosilicates with alkali metal hydroxides or silicates
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00Technologies relating to the processing of minerals
    • Y02P40/10Production of cement, e.g. improving or optimising the production methods; Cement grinding

Abstract

The invention relates to an excitant and a red mud fly ash cementing material. The activator consists of polymeric active aluminum, sodium hydroxide, sodium silicate and cement in the following mass percent: 30-35% of polymerized active aluminum, 10-20% of sodium hydroxide, 10-20% of sodium silicate and 35-40% of cement. After being mixed according to the weight percentage, the excitant is mixed into the red mud fly ash cementing material by 0.5-1.5 percent, the 7d strength can be improved by 15-35 percent, and the 28d strength can be improved by 30-50 percent. The invention can effectively stimulate the activity of the red mud fly ash cementing material, improve the strength of the cementing material, achieve the purpose of consuming a large amount of industrial wastes such as red mud, fly ash and the like, and has remarkable social benefit and economic benefit.

Description

Excitant and red mud fly ash cementing material
Technical Field
The invention relates to the technical field of industrial solid waste treatment, in particular to an excitant and a red mud fly ash cementing material.
Background
The red mud is a red powder mud-shaped strong-alkaline solid waste material which is remained after alumina is extracted from bauxite in the aluminum production industry. The main component of the material is SiO2、CaO、Fe2O3、Al2O3、Na2O、TiO2、K2Oxides such as O, and other elements, and ignition loss components and trace amounts of nonferrous metals. The red mud is classified into Bayer process red mud, sintering process red mud or combination process red mud due to different production processes. Generally, 1.0 to 2.0 tons of red mud are additionally produced per 1 ton of alumina produced on average. In order to improve the comprehensive utilization rate and technical level of red mud and reduce the influence of red mud stacking on environment and safety, the red mud comprehensive utilization guidance opinions (Ministry of industry and communications [ 2010 ] 401) were jointly issued by the Ministry of industry, informatization and science and technology in 2010, and key technologies such as the preparation of roadbed consolidation materials and environment restoration materials by red mud should be encouraged and developed are definitely proposed in the notification, and industrial application is actively carried out. The treatment and the comprehensive utilization of the red mud waste residue are a great worldwide problem. China can only be treated by piling up, filling the hollow land and discharging into the sea. Among them, the way of piling up and disposing and filling the depression is the main way.
China belongs to a big energy country, and mainly uses coal production capacity. The fine ash collected from the flue gas after coal combustion is called fly ash. The main oxide composition is as follows: SiO 22、Al2O3、FeO、Fe2O3、CaO、TiO2And the like. Along with the development of the power industry, the discharge amount of the fly ash is increased year by year, and a large amount of fly ash can generate dust and pollute the atmosphere without being treated; if discharged into the water system, the river will be silted up, and the toxic chemicals in the river will beSubstances can also be harmful to humans and organisms. As the fly ash has activity, the fly ash can be used as a mineral admixture to be added into concrete, thereby saving a large amount of cement and fine aggregate, reducing hydration heat and improving the impermeability of the concrete.
The strong alkali contained in the red mud can excite the fly ash to generate strength, and the red mud is applied to the fields of road materials, baking-free bricks, mine filling and the like. But the strength is usually 1 to 2MPa because of low strength. Therefore, how to improve the strength of the red mud cementing material is a technical problem which needs to be solved urgently by the technical personnel in the field.
Disclosure of Invention
The invention aims to provide an excitant capable of improving the red mud strength and a red mud fly ash cementing material.
The technical scheme adopted by the invention for solving the technical problem is as follows:
the activator consists of polymeric active aluminum, sodium hydroxide, sodium silicate and cement in the following mass percent: 30-35% of polymerized active aluminum, 10-20% of sodium hydroxide, 10-20% of sodium silicate and 35-40% of cement.
In the scheme, the volume weight of the exciting agent is as follows: 1050kg/m3~1140kg/m3
In the scheme, the polymeric active aluminum is polymeric aluminum chloride, polymeric aluminum sulfate or polymeric aluminum silicate.
In the scheme, the purity of the sodium hydroxide is more than or equal to 98-99%, and the impurity Na2CO3≤0.5-1%,NaCl≤0.03-0.08%,Fe2O3≤0.005-0.01%。
In the scheme, the modulus n of the sodium silicate is between 2.0 and 3.0.
In the above scheme, the cement is portland cement.
The red mud fly ash cementing material comprises an excitant with the external doping amount of 0.5-1.5% by mass, wherein the excitant is the excitant.
In the scheme, the red mud fly ash cementing material comprises red mud, fly ash, desulfurized gypsum and lime.
In the scheme, the mass ratio of the red mud, the fly ash, the desulfurized gypsum and the lime is 10:8:1: 1.
The invention takes polymeric active aluminum, sodium hydroxide and sodium silicate as main raw materials of an excitant, and the mechanism of the red mud fly ash cementing material is as follows:
the polymeric active aluminum is an inorganic polymeric flocculant widely used in water treatment, and aluminum in an aqueous solution can be complexed with water molecules or hydroxyl groups to form hydrated hydroxyl aluminum ions. The polymer gel has the characteristic of high charge and contains a large number of active groups, so that the average chain length and the polymerization degree of C-A-S-H gel molecules can be reduced after the polymer active aluminum is added, the C-A-S-H gel particles are more uniformly and finely distributed, and stronger Van der Waals force is shown. Meanwhile, the literature says that after Al is introduced into a gel molecular structure, the interlayer distance can be increased, the porosity of gel micropores is improved, and the diffusion of ions is easier. The hydration degree of the silica-alumina glass body (fly ash, slag and the like) is improved.
Sodium hydroxide, commonly known as caustic soda, is a caustic strong base with corrosive properties. OH generated by dissociation of it in water-Si-O-Si and Al-O-Al bonds in the alumino-silica glass body (fly ash, slag, etc.) are broken to form [ SiO ]4]4-And [ AlO ]4]5-Entering the liquid phase to form dispersed flocculated product. As the flocculent products are increased, condensation polymerization reaction occurs between flocculent phases to finally form gel or complex crystals and hydration products with amorphous structures, the pores of the gel material are filled, and a network structure is formed to wrap particles in the gel material, so that the strength of the gel material system is improved.
Sodium silicate is commonly known as water glass or sodium silicate. Hydrolysis thereof provides both OH-The ions promote the depolymerization of the alumino-silica vitreous body (fly ash, slag, etc.); and also provides [ SiO ]4]4-Ions, dissociating from the Si-rich phase of the glass body [ SiO ]4]4-Ca together with ions2+The plasma generates a cementitious substance.
The invention has the following beneficial effects:
1. the amount of the excitant used for the red mud fly ash cementing material is 0.5 to 1.5 percent of the cementing material.
2. The raw materials are added in an external doping mode, so that the process is simple and the operation is convenient.
3. The 7d strength of the cementing material can be improved by 15-25%, and the 28d strength can be improved by 20-30%. The invention can effectively stimulate the activity of the red mud fly ash cementing material, improve the strength of the red mud fly ash cementing material and widen the application field of the red mud.
Detailed Description
In order to more clearly understand the technical features, objects and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to examples.
Example 1
This example provides a trigger comprising a polymeric activated aluminum: 15g, sodium hydroxide: 7.5g, sodium silicate: 7.5g, cement: 20 g.
In this example, the polyaluminum is polyaluminum chloride.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.75 kg.
The preparation steps of the red mud fly ash cementing material are as follows:
a. all the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 2
This example provides a trigger comprising a polymeric activated aluminum: 15g, sodium hydroxide: 10g, sodium silicate: 5g, cement: 20 g.
In this embodiment, the polyaluminum is polyaluminum sulfate.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of exciting agent, wherein the required water amount is 2.78 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 3
This example provides a trigger comprising a polymeric activated aluminum: 15g, sodium hydroxide: 5g, sodium silicate: 10g, cement: 20 g.
In this example, the polyaluminum is polyaluminum chloride.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.74 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 4
This example provides a trigger comprising a polymeric activated aluminum: 17.5g, sodium hydroxide: 7.5g, sodium silicate: 7.5g, cement: 17.5 g.
In this example, the polymeric active aluminum is a polymeric aluminum silicate.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.83 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 5
This example provides a trigger comprising a polymeric activated aluminum: 17.5g, sodium hydroxide: 10g, sodium silicate: 5g, cement: 17.5 g.
In this example, the polyaluminum is polyaluminum chloride.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.81 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 6
This example provides a trigger comprising a polymeric activated aluminum: 17.5g, sodium hydroxide: 5g, sodium silicate: 10g, cement: 17.5 g.
In this embodiment, the polyaluminum is polyaluminum sulfate.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.83 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 7
This example provides a trigger comprising a polymeric activated aluminum: 15g, sodium hydroxide: 10g, sodium silicate: 7.5g, cement: 17.5 g.
In this example, the polyaluminum is polyaluminum chloride.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.76 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
Example 8
This example provides a trigger comprising a polymeric activated aluminum: 15g, sodium hydroxide: 7.5g, sodium silicate: 10g, cement: 17.5 g.
In this example, the polymeric active aluminum is a polymeric aluminum silicate.
The embodiment also provides a red mud fly ash cementing material, which comprises the following raw materials: 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum, 0.5kg of lime and 50g of excitant, wherein the required water amount is 2.74 kg.
a. All the solid raw materials are added into a stirrer according to the proportion and are uniformly mixed.
b. Weighing the excitant with the total content of the solid raw materials being 0.5 percent, adding the excitant in an external mixing mode, and mixing uniformly.
c. Adding water into the uniformly mixed dry materials in proportion, and then fully and uniformly stirring.
The unconfined compressive strengths of 7d and 28d of the above examples and comparative test results are given in Table 1 below.
The reference sample comprises 5kg of red mud, 4kg of fly ash, 0.5kg of desulfurized gypsum and 0.5kg of lime. The amount of water required was 2.71 kg.
Table 1 strength test results of the invention:
Figure GDA0001735180240000051
while embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, which are intended to be illustrative rather than limiting, and many modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (9)

1. The activator is characterized by comprising polymeric active aluminum, sodium hydroxide, sodium silicate and cement in the following mass percent: 30-35% of polymerized active aluminum, 10-20% of sodium hydroxide, 10-20% of sodium silicate and 35-40% of cement.
2. A booster as claimed in claim 1, wherein the booster has a volume weight of: 1050kg/m3~1140kg/m3
3. The activator according to claim 1, characterized in that the polymeric active aluminum is polyaluminum chloride, polyaluminum sulfate or polyaluminum silicate.
4. The excitant of claim 1, wherein the purity of the sodium hydroxide is greater than or equal to 98-99%, and impurity Na is2CO3≤0.5-1%,NaCl≤0.03-0.08%,Fe2O3≤0.005-0.01%。
5. The trigger according to claim 1, wherein the sodium silicate modulus n is between 2.0 and 3.0.
6. The agent as claimed in claim 1, wherein the cement is portland cement.
7. The red mud fly ash cementing material is characterized by comprising an excitant with the external doping amount accounting for 0.5-1.5% of the mass percent of the red mud fly ash cementing material, wherein the excitant is the excitant according to any one of claims 1-6.
8. The red mud fly ash cementitious material of claim 7, wherein the red mud fly ash cementitious material comprises red mud, fly ash, desulfurized gypsum and lime.
9. The red mud fly ash cementing material of claim 8, wherein the mass ratio of the red mud, the fly ash, the desulfurized gypsum and the lime is 10:8:1: 1.
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CN109485286B (en) * 2019-01-22 2021-06-18 山东淄创新材料科技有限公司 Accelerant for red mud baking-free brick and preparation method thereof
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CN110467368B (en) * 2019-09-11 2021-11-26 上海海顾新材料科技有限公司 Active excitant for inorganic solid waste building material and preparation method thereof
CN110776267A (en) * 2019-11-06 2020-02-11 中冶南方都市环保工程技术股份有限公司 Inorganic cementing material prepared from Bayer process red mud and preparation method thereof
CN110759680B (en) * 2019-11-14 2021-02-23 山东大学 Red mud utilization method based on cooperative treatment of industrial tail gas, sewage treatment and green high-performance civil functional material
CN111548039B (en) * 2020-04-22 2022-05-27 深圳大学 Red mud geopolymer aggregate and preparation method thereof
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CN103553492B (en) * 2013-10-16 2016-01-20 山东大学 It is a kind of that with polyaluminium waste slag of aluminum and red mud, to be major ingredient non-burning brick and preparation method thereof

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