WO2022142137A1

WO2022142137A1 - Red mud-based cementing material, red mud-based lightweight aggregate, red mud-based lightweight aggregate concrete and preparation method therefor

Info

Publication number: WO2022142137A1
Application number: PCT/CN2021/098461
Authority: WO
Inventors: 王文龙; 张超; 王旭江; 李敬伟; 吴长亮; 蒋稳; 王冠
Original assignee: 山东大学
Priority date: 2020-12-29
Filing date: 2021-06-04
Publication date: 2022-07-07
Also published as: CN112723764A

Abstract

Disclosed in the present invention are a red mud-based cementing material, red mud-based lightweight aggregate, red mud-based lightweight aggregate concrete and a preparation method therefor. The red mud-based cementing material having a high performance and a low cost, a geopolymer cementing material, a foaming agent and an organosilicon waterproofing agent material are used, improving the performance of the red mud-based lightweight aggregate, and thus improving the performance of the lightweight aggregate concrete, i.e., improving the strength of the red mud-based lightweight aggregate/lightweight aggregate concrete, and improving the durability of the red mud-based lightweight aggregate/lightweight aggregate concrete. The red mud-based cementing material is a sulfur-aluminum-based cementing material having a low alkalinity, and a geopolymer such as sodium aluminosilicate/calcium aluminosilicate formed in the preparation process of the red mud-based lightweight aggregate, and Na+ can be cured. In the combination of the red mud-based cementing material and Na+, the alkalinity of the concrete is reduced while the strength of the uncalcined lightweight aggregate is improved, alleviating the alkali aggregate reaction of the lightweight aggregate concrete, and improving the durability of the lightweight aggregate concrete. The addition of the hydrogen peroxide foaming agent can reduce the density of the uncalcined lightweight aggregate, and the organosilicon waterproofing agent can reduce the water absorption rate of the uncalcined lightweight aggregate.

Description

Red mud-based cementitious material, red mud-based lightweight aggregate, red mud-based lightweight aggregate concrete and preparation method thereof

technical field

The invention relates to the technical field of solid waste utilization, in particular to a red mud-based cementitious material, red mud-based lightweight aggregate, red mud-based lightweight aggregate concrete and a preparation method thereof. The utilization rate of red mud is greatly improved, and the red mud-based products have good performance at the same time.

Background technique

The disclosure of information in this Background section is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

At present, most of the existing technologies for preparing lightweight aggregate concrete use natural aggregates and sintered ceramsite as lightweight aggregates, and the utilization of red mud is limited to the use of admixtures. Most of the red mud-based aggregates used to prepare light-weight aggregate concrete using red mud-based lightweight aggregates as raw materials also use sintered red mud aggregates.

The inventor found that there are the following problems in the related technology of red mud resource utilization in the prior art: (1) in the process of preparing building materials by red mud resource utilization, the utilization of red mud is only realized for a certain preparation link, and the utilization of red mud is not realized. Multi-level iteration and comprehensive utilization of red mud is realized, resulting in low utilization rate of red mud. (2) At present, sintered lightweight aggregate or natural lightweight aggregate and ordinary silica cement are mainly used as raw materials in the process of preparing lightweight aggregate concrete, and the reaction of alkali aggregate has a great influence on the durability of concrete; The technology of aggregate is mainly prepared by sintering method, and part of it is prepared by non-sintering. However, the red mud-based light aggregate prepared by non-sintering generally has the problems of high density, low strength and high water absorption.

SUMMARY OF THE INVENTION

In view of the technical problems existing in the prior art, the present invention provides a red mud-based cementitious material, a red mud-based lightweight aggregate, a red mud-based lightweight aggregate concrete and a preparation method thereof.

In order to solve the above technical problems, the following one or more embodiments of the present invention provide the following technical solutions:

In a first aspect, the present invention provides a method for preparing a red mud-based cementitious material, comprising the following steps:

After drying the red mud or red mud-based waste slag, aluminum slag, desulfurized gypsum and limestone tailings, they are mixed and ground in a mass ratio of 15-25:20-35:20-30:25-35;

calcining the ground mixed powder to prepare red mud-based cementitious material clinker;

The red mud-based cementitious material is mixed and ground with desulfurized gypsum to prepare the red mud-based cementitious material.

In a second aspect, the present invention provides a red mud-based cementitious material prepared by the above method for preparing a red mud-based cementitious material.

In the third aspect, the present invention provides a preparation method of red mud-based light aggregate, comprising the following steps:

After mixing and grinding the red mud-based cementitious material, fly ash and red mud according to a set ratio, sieving to obtain mixed powder;

The mixed powder is granulated, and the hydrogen peroxide foaming agent solution is sprayed in the granulation process;

After curing the granulated mixture particles, water repellent is sprayed on their surfaces to obtain red mud-based light aggregates.

In a fourth aspect, the present invention provides a red mud-based lightweight aggregate prepared by the above method for preparing the red mud-based lightweight aggregate.

A fifth aspect, the present invention provides a preparation method of red mud-based lightweight aggregate concrete, comprising the following steps:

Screening the prepared red mud-based light aggregates to obtain 0.15-1mm light and fine aggregates to replace ordinary light sand, and 5-20mm continuous graded light and coarse aggregates to replace limestone aggregates for use;

After premixing the red mud-based cementitious material, the red mud-based light-fine aggregate and the red-mud-based light-coarse aggregate, water and a water-reducing agent are added, and the mixture is uniform to obtain the red mud-based light-weight aggregate concrete.

In a sixth aspect, the present invention provides a red mud-based lightweight aggregate concrete prepared by the above method for preparing the red mud-based lightweight aggregate concrete.

Compared with the prior art, the beneficial effects of the above embodiments of the present invention are:

1. Realize the multi-level iterative utilization and comprehensive utilization of red mud, greatly improve the utilization rate of red mud, and make the utilization rate of red mud reach more than 80%.

2. Use high-performance and low-cost red mud-based cementitious materials, geopolymer cementing materials, foaming agents and silicone waterproofing materials to improve the performance of red mud-based lightweight aggregates, and then realize the performance improvement of lightweight aggregate concrete. Lifting, not only improves the strength of red mud-based light aggregate/light aggregate concrete, but also improves its durability.

Red mud-based cementitious materials are low-alkalinity sulfur-aluminum-based cementitious materials, and the preparation process of red mud-based light aggregates forms geopolymers such as sodium aluminosilicate/calcium aluminosilicate, which can achieve Na ⁺ solidification. While improving the strength of the non-burning lightweight aggregate, the alkalinity of the concrete is reduced, thereby alleviating the alkali-aggregate reaction of the lightweight aggregate concrete and improving its durability. The addition of hydrogen peroxide foaming agent can reduce the density of non-burning lightweight aggregate, and the silicone waterproofing agent can reduce its water absorption.

3. The non-burning lightweight aggregate product and the lightweight aggregate concrete product prepared by the present invention do not need steam curing.

4. The bulk density of the red mud-based non-burning light aggregate product prepared by the present invention is 710-1080Kg/m ³ , the cylinder compressive strength is 3.8-8.6Mpa, the water absorption rate is 7.2-10%, and the softening coefficient is 0.66-0.71, The Na ₂ O content is 2.5-3%.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

Fig. 1 is the process flow diagram of the multi-stage iterative utilization of red mud according to the embodiment of the present invention to prepare lightweight aggregate concrete;

Fig. 2 is the XRD pattern of the red mud-based cementitious material prepared in Example 1 of the present invention;

Fig. 3 is the topography diagram of the red mud-based lightweight aggregate prepared in Example 1 of the present invention;

Figure 4 is a comparison chart of the compressive strength of the red mud-based lightweight aggregate concrete prepared in Examples 1-3 of the present invention and the reference group.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

The preparation of red mud-based cementitious materials is a synergistic complement of silicon-aluminum-iron-based solid waste and calcium sulfate-based solid waste, in which red mud and aluminum slag, as silicon-aluminum-iron-based solid waste, can provide Si sources for the preparation of red mud-based cementitious materials and Al source, while limestone tailings and desulfurization gypsum as calcium sulfate-based solid waste can provide Ca source for material preparation. Limestone tailings are rich in calcium carbonate, which can provide sufficient calcium source for material preparation.

In some embodiments, the calcination temperature is 1210-1230° C., and the calcination time is 1.5-2.5 h.

Further, the calcination temperature is 1215-1225°C, and the calcination time is 1.7-2.2h.

Further, the calcination temperature is 1220°C, and the calcination time is 2h.

In some embodiments, the mass ratio of red mud-based cementitious material clinker to desulfurized gypsum is 90-96:4:10.

The bulk density of fly ash is only about 2/3 of that of cement, and the particle shape is good, and fly ash contains a lot of glass microbeads, which can play the role of micro-aggregate to make the light aggregate more compact. While reducing the density, the strength of lightweight aggregates can be improved; in addition, fly ash is rich in active silicon-alumina components and has alkali-activated activity, while the alkali metal Na ₂ O content in red mud is high and the alkalinity is strong, and the synergistic effect of the two can be The formation of dense sodium aluminosilicate/calcium aluminosilicate and other geopolymer cementitious materials can increase the strength of lightweight aggregates while achieving Na ⁺ effective solidification, thereby reducing the alkalinity of lightweight aggregates and relieving red mud-based aggregates. Frost phenomenon.

The prepared red mud-based cementitious material is an early-strength and fast-hardening cementitious material with an initial setting time of 10-15min. In the process of preparing light aggregates, a dynamic foaming process of simultaneous granulation and simultaneous foaming needs to be realized. The preferred hydrogen peroxide is a blowing agent that completes the foaming process before the material sets.

In some embodiments, the mass ratio of the red mud-based cementitious material, fly ash and red mud is 10-30:5-15:70-90.

Further, the mesh number of sieving is 140-160 mesh.

In some embodiments, the mass percentage of hydrogen peroxide in the hydrogen peroxide foaming agent solution is 0.2%-1%.

In some embodiments, the parameters of the granulator are: diameter: 70-100cm, rotation speed 30-40rpm, angle 40°-50°, granulation time 8-12min, the foaming agent solution is sprayed on the surface of the light aggregate With water stains, the water-cement ratio is controlled at 0.3-0.38.

In some embodiments, the curing time for the granulated mixture granules is 5-10 d, preferably 7 d.

Normal temperature and pressure curing, temperature 25 ℃, humidity 99%.

In some embodiments, the mass concentration of the silicone water repellent is 4-9%, preferably 5%.

In some embodiments, the water reducing agent is a polycarboxylate water reducing agent.

In some embodiments, it also includes the steps of collecting, crushing, and grinding the residue in the preparation process as a raw material for preparing the red mud-based cementitious material.

Example 1

As shown in Figure 1, described red mud-based cementitious material preparation steps are as follows: (1) red mud, aluminum slag, desulfurization gypsum, limestone tailings are dried for subsequent use; (2) 15 parts of red mud are taken respectively; 35 parts of ore; 30 parts of desulfurized gypsum; 20 parts of aluminum slag. The red mud is combined with limestone tailings, aluminum slag, and desulfurized gypsum after grinding and mixing to prepare red mud-based cementitious material clinker. The calcination temperature is 1220 ° C, and the calcination time 2h. The XRD pattern of the prepared red mud-based cementitious material is shown in Figure 2.

The red mud-based cementitious material clinker is calculated in parts by mass, red mud-based cementitious material clinker: desulfurized gypsum 95%: 5%, mixed and ground to obtain the red mud-based cementitious material.

The preparation steps of the red mud-based light aggregate are as follows: (1) 20 parts of the red mud-based cementitious material, 10 parts of fly ash, and 70 parts of red mud are uniformly mixed and ground through a 150-mesh sieve according to the mass fraction; 15 ml of H ₂ O ₂ solution with a mass fraction of 30% was added to 1.455 L of water and diluted to obtain a foaming agent solution; (3) the above mixture was placed in a disc granulator, and the foaming agent solution was sprayed to prepare red mud-based light bone The parameters of the granulator: diameter: 80cm, rotation speed 33rpm, angle 45°, granulation time 10min, the foaming agent solution is sprayed with a slight water stain on the surface of the light aggregate, and the water-cement ratio is controlled to 0.3- 0.38 is appropriate; (4) the above-mentioned red mud-based light aggregates are cured at room temperature and pressure for 7 days; (5) Calculated by mass fraction: take 5% of silicone water repellant, spray it on the surface of light aggregates for later use; (6) put the red mud The basic light aggregates are screened into 0.15-1mm light and fine aggregates instead of ordinary light sand, and 5-20mm continuous gradation light and coarse aggregates are used instead of limestone aggregates. The morphology of the prepared red mud-based lightweight aggregate is shown in Figure 3.

The light-weight aggregate concrete preparation steps are as follows: 520 parts of red mud-based cementitious materials, 707 parts of red mud-based light and fine aggregates, and 575 parts of red mud-based light and coarse aggregates prepared in the previous steps of this embodiment are put into a drum. Type mixer for 15min, then poured into the mixed solution prepared by 168 parts of water and 4 parts of polycarboxylate superplasticizer, and mixed evenly to obtain red mud-based lightweight aggregate concrete.

The properties of the prepared red mud-based cementitious material: the compressive strength of mortar is 3d 49.6Mpa, 28d 58.3Mpa, the flexural strength is 3d 6.9Mpa, and 28d 7.6Mpa. Density 2.83g/cm ^-3 , specific surface area 373m ² /kg, setting time: initial setting 25min, final setting 60min.

Properties of the prepared red mud-based lightweight aggregate: bulk density: 1080kg/m ³ , apparent density: 1820kg/m ³ , water absorption: 7.2%, cylinder compressive strength: 8.6Mpa, softening coefficient 0.66, Na ₂ O content 1.15% .

The prepared red mud-based lightweight aggregate concrete performance: slump: 95mm, 28d compressive strength 51.8Mpa. Flexural strength: 5.07Mpa, split tensile strength 4.22Mpa, dry density: 1916Kg/m ³ .

Example 2

The preparation steps of the red mud-based cementitious material are as follows: (1) drying red mud, aluminum slag, desulfurized gypsum and tailings for later use; (2) respectively taking 20 parts of red mud; 30 parts of limestone tailings; 25 parts of desulfurized gypsum 25 parts of aluminum slag. The red mud is combined with limestone tailings, aluminum slag, and desulfurized gypsum to be uniformly ground and mixed, and then calcined to prepare red mud-based cementitious material clinker.

The preparation steps of the red mud-based light aggregate are as follows: (1) 20 parts of red mud-based cementitious materials, 15 parts of fly ash, and 65 parts of red mud are uniformly mixed and ground through a 150-mesh sieve by mass fraction; (2) ) Take 45 ml of H ₂ O ₂ solution with a mass fraction of 30% and add it to 1.455 L of water to dilute to obtain a foaming agent solution; (3) place the above mixture in a disc granulator, spray the foaming agent solution to prepare a red mud base Lightweight aggregate (parameters of the granulator: diameter: 80cm, rotating speed 33rpm, angle 45°, granulation time 10min, the foaming agent solution is sprayed with a slight water stain on the surface of the light aggregate, and the water-cement ratio is controlled 0.3-0.38 is suitable); (4) The above-mentioned red mud-based light aggregates are cured at room temperature and pressure for 7 days; (5) Calculated by mass fraction: take 5% of silicone waterproofing agent and spray it on the surface of light aggregates for later use; (6) The red mud-based light aggregates are screened into 0.15-1mm light and fine aggregates instead of ordinary light sand, and 5-20mm continuously graded light and coarse aggregates are used instead of limestone aggregates.

The light-weight aggregate concrete preparation steps are as follows: put 520 parts of red mud-based cementitious materials, 707 parts of red mud-based light and fine aggregates, and 575 parts of red mud-based light and coarse aggregates prepared in the previous steps of this example into a drum. Type mixer for 15min, then poured into the mixed solution prepared by 160 parts of water and 4 parts of polycarboxylate superplasticizer, and mixed evenly to obtain red mud-based lightweight aggregate concrete.

The properties of the prepared red mud-based cementitious material: the compressive strength of mortar is 3d 52.8Mpa, 28d 68.5Mpa, the flexural strength is 3d7.2Mpa, and 28d 8.3Mpa. Density 2.88g/cm ^-3 , specific surface area 385m ² /kg, setting time: initial setting 20min, final setting 50min.

Properties of the prepared red mud-based lightweight aggregate: bulk density: 830kg/m ³ , apparent density: 1700kg/m ³ , water absorption: 9.1%, cylinder compressive strength: 5.8Mpa, softening coefficient 0.71Na ₂ O, content 1.1% .

The prepared red mud-based lightweight aggregate concrete performance: slump: 98mm, 28d compressive strength 52.2Mpa. Flexural strength: 5.5Mpa, split tensile strength 4.5Mpa, dry density: 1830Kg/m ³ .

Example 3

The preparation steps of the red mud-based cementitious material are as follows: (1) drying red mud, aluminum slag, desulfurized gypsum and tailings for later use; (2) respectively taking 20 parts of red mud; 30 parts of limestone tailings; 25 parts of desulfurized gypsum 25 parts of aluminum slag. The red mud is combined with limestone tailings, aluminum slag, and desulfurized gypsum to be uniformly ground and mixed, and then calcined to prepare red mud-based cementitious material clinker. The red mud-based cementitious material clinker is calculated in parts by mass, red mud-based cementitious material clinker: desulfurized gypsum 95:5, mixed and ground to obtain the red mud-based cementitious material.

The preparation steps of the red mud-based light aggregate are as follows: (1) Counting by mass fraction, 20 parts of red mud-based cementitious materials, 15 parts of fly ash, and 65 parts of red mud are uniformly mixed and pulverized through a 150-mesh sieve; ( 2) Take 75 ml of H ₂ O ₂ solution with a mass fraction of 30% and add it to 1.455 L of water to dilute to obtain a foaming agent solution; (3) place the above mixture in a disc granulator, spray the foaming agent solution to prepare red mud Based on light aggregate; the parameters of the granulator: diameter: 80cm, rotation speed 33rpm, angle 45°, granulation time 10min, the foaming agent solution is sprayed with a slight water stain on the surface of the light aggregate, and the water-cement ratio It is appropriate to control 0.3-0.38; (4) the above-mentioned red mud-based light aggregates are cured at room temperature and pressure for 7 days; (5) According to the mass fraction: take 5% of the silicone waterproofing agent, spray it on the surface of the light aggregates for use; (6) The red mud-based light aggregates are screened into 0.15-1mm light and fine aggregates instead of ordinary light sand, and 5-20mm continuously graded light and coarse aggregates are used instead of limestone aggregates.

The preparation steps of the lightweight aggregate concrete are as follows: 450-520 parts of the red mud-based cementitious material prepared in the previous steps of this embodiment, 650-750 parts of the red mud-based light and fine aggregate, and 500-750 parts of the red mud-based light and coarse aggregate 600 parts, put it into a drum mixer and stir for 15 minutes, then pour in the mixed solution prepared by 160 parts of water and 4 parts of polycarboxylate water-reducing agent, and mix evenly to obtain red mud-based lightweight aggregate concrete.

The properties of the prepared red mud-based cementitious material: the compressive strength of mortar is 3d 52.8Mpa, 28d 68.5Mpa, the flexural strength is 3d 7.2Mpa, and 28d 8.3Mpa. Density 2.88g/cm ^-3 , specific surface area 385m ² /kg, setting time: initial setting 20min, final setting 50min.

The properties of the prepared red mud-based lightweight aggregate: bulk density: 710kg/m ³ , apparent density: 1620kg/m ³ , water absorption rate: 10%, cylinder compressive strength: 3.2Mpa, softening coefficient 0.71Na ₂ O, content 1.15% .

The properties of the prepared red mud-based lightweight aggregate concrete: slump: 98mm, 28d compressive strength: 45.5Mpa. Flexural strength: 4.3Mpa, splitting tensile strength: 3.2Mpa, dry density: 1720Kg/m ³ .

Reference group:

The cementitious material does not use the red mud-based cementitious material used in the present invention, and the cementitious material of the reference group adopts 425 ordinary Portland cement. In this reference group, ordinary light sand is used as the fine aggregate, and sintered ceramsite with continuous gradation is used as the coarse aggregate. The preparation steps of the lightweight aggregate concrete are as follows: 520 parts of ordinary Portland cement, 707 parts of red light sand aggregate, and 575 parts of 5-25 continuous grading sintered ceramsite are put into a drum mixer for stirring for 15 minutes, and then poured into Lightweight aggregate concrete is obtained by mixing 168 parts of water and 4 parts of polycarboxylate superplasticizer.

The properties of the selected ordinary Portland cement: compressive strength of mortar 3d 28.9Mpa, 28d 46.5Mpa, flexural strength 3d 6.3Mpa, 28d 8.2Mpa. Density 2.85g/cm ^-3 , specific surface area 423m ² /kg, setting time: initial setting 190min, final setting 248min.

The properties of the selected sintered ceramsite: bulk density: 850kg/m ³ , apparent density: 1650kg/m ³ , water absorption rate: 11%, cylinder compressive strength: 5.5Mpa, softening coefficient 0.66.

The prepared red mud-based lightweight aggregate concrete performance: slump: 95mm, 28d compressive strength 48.2Mpa. Flexural strength: 4.3Mpa, split tensile strength 3.56Mpa, dry density: 1730Kg/m ³ .

Comparative Example 1

Compared with Example 1, the limestone tailings were replaced with iron tailings, and the others were the same as Example 1.

The properties of the prepared red mud-based cementitious material: the compressive strength of mortar is 3d 35.6Mpa, 28d 45.8Mpa, the flexural strength is 3d 6.1Mpa, and 28d 6.3Mpa. Density 2.95g/cm ^-3 , specific surface area 353m ² /kg, setting time: initial setting 20min, final setting 60min.

Properties of the prepared red mud-based lightweight aggregate: bulk density: 1100kg/m ³ , apparent density: 1920kg/m ³ , water absorption rate: 7.2%, cylinder compressive strength: 7.6Mpa, softening coefficient 0.72, Na ₂ O content 2.25% .

The prepared red mud-based lightweight aggregate concrete performance: slump: 95mm, 28d compressive strength 46.5Mpa. Flexural strength: 4.8Mpa, split tensile strength 3.6Mpa, dry density: 1950Kg/m ³ .

Comparative Example 2

Compared with Example 1, the hydrogen peroxide foaming agent solution was replaced with Al powder foaming agent, and the others were the same as Example 1.

Properties of the prepared red mud-based lightweight aggregate: bulk density: 1150kg/m ³ , apparent density: 2002kg/m ³ , water absorption rate: 6.5%, cylinder compressive strength: 9.1Mpa, softening coefficient 0.56, Na ₂ O content 1.15% .

The prepared red mud-based lightweight aggregate concrete performance: slump: 95mm, 28d compressive strength 54.8Mpa. Flexural strength: 6.1Mpa, split tensile strength 4.8Mpa, dry density: 2100Kg/m ³ .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

A method for preparing a red mud-based cementitious material, comprising the steps of:

After drying the red mud or red mud-based waste slag, aluminum slag, desulfurized gypsum and limestone tailings, they are mixed and ground in a mass ratio of 15-25:20-35:20-30:25-35;

calcining the ground mixed powder to prepare red mud-based cementitious material clinker;

The red mud-based cementitious material is mixed and ground with desulfurized gypsum to prepare the red mud-based cementitious material.
The method for preparing a red mud-based cementitious material according to claim 1, wherein the calcination temperature is 1210-1230°C, and the calcination time is 1.5-2.5h;

Further, the calcination temperature is 1215-1225°C, and the calcination time is 1.7-2.2h;

Further, the calcination temperature is 1220°C, and the calcination time is 2h;

Further, the mass ratio of the red mud-based cementitious material clinker to the desulfurized gypsum is 90-96:4:10.
A red mud-based cementitious material is characterized in that: it is prepared by the preparation method of the red mud-based cementitious material according to any one of claims 1 or 2.
A preparation method of red mud-based light aggregate is characterized in that: comprising the following steps:

After the red mud-based cementitious material of claim 3, fly ash and red mud are mixed and pulverized in a set ratio, sieved to obtain mixed powder;

The mixed powder is granulated, and the hydrogen peroxide foaming agent solution is sprayed in the granulation process;

After curing the granulated mixture particles, water repellent is sprayed on their surfaces to obtain red mud-based light aggregates.
The method for preparing red mud-based lightweight aggregate according to claim 4, wherein the mass ratio of the red mud-based cementitious material, fly ash and red mud is 10-30:5-15:70- 90;

Further, the mesh number of sieving is 140-160 mesh;

In some embodiments, the mass percentage of hydrogen peroxide in the hydrogen peroxide foaming agent solution is 0.2%-1%;

In some embodiments, the parameters of the granulator are: diameter: 70-100cm, rotation speed 30-40rpm, angle 40°-50°, granulation time 8-12min, the foaming agent solution is sprayed on the surface of the light aggregate With water stains, the water-cement ratio is controlled at 0.3-0.38;

Further, the curing time for the granulated mixture particles is 5-10 d, preferably 7 d.
The method for preparing red mud-based lightweight aggregate according to claim 4, wherein the mass concentration of the organosilicon waterproofing agent is 4-9%, preferably 5%.
A red mud-based lightweight aggregate is characterized in that: it is prepared by the preparation method of the red mud-based lightweight aggregate according to any one of claims 4-6.
A preparation method of red mud-based lightweight aggregate concrete, characterized in that: comprising the following steps:

Screening the prepared red mud-based light aggregates to obtain 0.15-1mm light and fine aggregates to replace ordinary light sand, and 5-20mm continuous graded light and coarse aggregates to replace limestone aggregates for use;

After premixing the red mud-based cementitious material, the red mud-based light-fine aggregate, and the red-mud-based light-coarse aggregate, water and a water reducing agent are added, and the mixture is uniform to obtain the red mud-based light-weight aggregate concrete.
The preparation method of red mud-based lightweight aggregate concrete according to claim 8, characterized in that: the water reducing agent is a polycarboxylate water reducing agent;

Further, it also includes the steps of collecting, crushing and pulverizing the residue in the preparation process as a raw material for the preparation of the red mud-based cementitious material.
A red mud-based lightweight aggregate concrete is characterized in that: it is prepared by the preparation method of the red mud-based lightweight aggregate concrete according to claim 8 or 9.