All-red-mud-based stabilized macadam light mixture suitable for road base and preparation method of all-red-mud-based stabilized macadam light mixture

Abstract

The invention relates to the field of solid waste resource utilization research, in particular to an all-red-mud-based stabilized macadam light mixture suitable for a road base and a preparation method thereof, and the all-red-mud-based stabilized macadam light mixture comprises the following components in parts by mass: 50-70 parts of a fired red mud coarse aggregate component, 20-40 parts of a fired red mud fine aggregate component and 10-20 parts of a red mud-based cementing material component. According to the all-red-mud-based stabilized macadam light mixture suitable for the road base, large-scale resource utilization of industrial waste red mud can be achieved, and compared with a traditional macadam mixture, the all-red-mud-based stabilized macadam light mixture is small in density, has the good strength characteristic, and is suitable for the road base. The requirement of the road base on the bearing capacity can be met, and environmental protection and sustainable development are facilitated.

Description

Technical Field

[0001] The invention belongs to the research field of solid waste resource utilization, and specifically relates to a full red mud-based stabilized crushed stone lightweight mixture suitable for a road base and a preparation method thereof. Background Art

[0002] Red mud is a solid waste generated during the production process of alumina industry. Usually, for every ton of alumina produced, 1.0-1.8 tons of red mud will be produced. With the rapid development of the global aluminum industry, the output of red mud has increased year by year. According to statistics, the production of red mud in China reached 107 million tons in 2023. A large amount of red mud requires a lot of land for stacking, which brings huge land resource pressure to enterprises and local areas. On the one hand, red mud is strongly alkaline, and the alkali in it will penetrate into the ground, change the pH of the soil, destroy the structure and microbial community of the soil, and lead to a decrease in soil fertility. On the other hand, heavy metal ions and other harmful substances in red mud, such as sodium, aluminum, and iron, will seep into groundwater or surface water under the scouring of rainwater, causing water pollution, threatening the survival of aquatic organisms and the utilization of water resources; in addition, red mud dumps are prone to dust flying under dry and windy weather conditions, and fine particles will enter the atmosphere, causing air pollution. Therefore, it is very important to realize the large-scale resource utilization of red mud solid waste.

[0003] At present, with the continuous advancement of science and technology, some new technologies and processes are constantly emerging, providing technical support for the comprehensive utilization of red mud. For example, the dealkalization technology of red mud, the extraction technology of valuable metals, and the technology of preparing building materials from red mud have made certain progress, making the comprehensive utilization of red mud more feasible and economical. For example, in the invention CN118854065A-"A method for extracting multi-metal elements from coal gasification fine slag", the author mixed red mud and coal gasification fine slag in proportion, crushed, ground, and microwave activated, and adopted a method of coordinating the separation of metal elements with red mud to achieve the extraction of valuable elements such as Fe, Al, and Ca in coal gasification slag; for example, in the invention CN118851712A-"A kind of alkali-activated cementitious material and its preparation method", the author mixed the alkali activator aqueous solution with the mixture of lead-zinc slag, coal gangue, fly ash and red mud, vibrated and demolded, and cured to obtain an alkali-activated cementitious material.

[0004] In most related inventions, red mud is only used as a medium or as a small part of the material to achieve the reuse of red mud, and the purpose of large-scale disposal of red mud is not achieved. The situation of resource utilization of red mud is still severe, so it is urgent to find a method to consume a large amount of red mud and realize the resource utilization of red mud solid waste. Summary of the invention

[0005] Based on the problems existing in the prior art, the present invention proposes a fully red mud-based stabilized crushed stone lightweight mixture suitable for road base and a preparation method thereof, which can consume a large amount of red mud and reduce carbon emissions, and has good strength characteristics, can meet the strength requirements of road base materials, and is in line with the concept of sustainable development.

[0006] The present invention adopts the following technical solution:

[0007] A fully red mud-based stabilized crushed stone lightweight mixture suitable for road base, comprising the following components in parts by mass:

[0008] Burnt red mud coarse aggregate component: 50-70 parts;

[0009] Burnt red mud fine aggregate component: 20-40 parts;

[0010] Red mud-based binder component: 12-20 parts.

[0011] Furthermore, the fired red mud coarse aggregate component and the fired red mud fine aggregate component are both made from red mud by a disc ball forming method to form red mud balls with uniform size and regular shape; they are calcined at 1000°C-1200°C for 2-4 hours and then cooled to room temperature using a ventilation cooling device.

[0012] Furthermore, the fired red mud coarse aggregate component has a particle sphericity between 0.6 and 0.8, a flattening rate less than 0.5, and a particle size distribution as follows:

[0013] 20mm-30mm: 16%-24%;

[0014] 10mm-20mm: 52%-61%;

[0015] 5mm-10mm:32%-35%.

[0016] Furthermore, in the burnt red mud fine aggregate component, the pass rate of the burnt red mud through a 0.3 mm sieve hole is greater than 65%.

[0017] Furthermore, the red mud-based cementing material comprises the following components in parts by mass:

[0018] Red mud: 8-12 parts;

[0019] Activator: 1-3 parts;

[0020] Enhancer: 1-3 parts;

[0021] Water: 2-4 parts.

[0022] Furthermore, in the red mud-based cementing material component, SiO 2The content is greater than 15wt%, the CaO content is greater than 25wt%, and the water content is less than 0.5wt%.

[0023] Furthermore, the activator is an activator sodium silicate solution.

[0024] Furthermore, the reinforcing agent is sulfonated melamine formaldehyde resin.

[0025] The present invention also provides a method for preparing the full red mud-based stabilized crushed stone lightweight mixture suitable for road base, comprising the following steps:

[0026] S1. First, the red mud is mechanically dried, and the red mud raw material is placed in an oven at 110°C for 8 hours and stored under dry and room temperature conditions. The moisture content in the test value is required to be less than 0.5wt%, and the red mud SiO 2 The content is greater than 15wt%, and the CaO content is greater than 25wt%;

[0027] S2. Put the red mud into a disc ball forming machine, set the disc speed between 5-20r / min, add water to the disc during the rotation of the disc for water spraying and humidification, so that the red mud gradually forms a state with a certain plasticity, and the disc ball forming method is used to make red mud balls with relatively uniform size and regular shape;

[0028] S3. Place the red mud pellets in a rotary kiln for firing at 1000-1200°C for 2-4 hours, then cool them to room temperature using a ventilation cooling device to obtain a finished product, and then screen them to obtain fired red mud coarse aggregate and fired red mud fine aggregate; the aggregate bulk density is required to be less than 1200kg / m 3 , cylinder pressure strength is greater than 5Mpa;

[0029] S4. Put the red mud and activator into a ball mill in proportion, mill at a speed of 200-300r / min for 5-8min to form a uniform mixture, then add water and enhancer in proportion, put into a high-powered mixer and stir for 3-5min to form a red mud-based cementing material;

[0030] S5. The burned red mud coarse aggregate, burned red mud fine aggregate and red mud-based binder material are mixed uniformly by a mixer to obtain the fully red mud-based stabilized gravel lightweight mixture suitable for the road base;

[0031] The obtained all-red mud-based stabilized crushed stone lightweight mixture suitable for road base has a bulk density of less than 1200kg / m 3 , the rebound modulus is greater than 300MPa, and the 7d unconfined compressive strength is greater than 3MPa.

[0032] The beneficial effects of the present invention include:

[0033] 1. The fully red mud-based stabilized crushed stone lightweight mixture suitable for road base of the present invention can consume a large amount of red mud when used in road base construction, reduce land occupation and environmental risks caused by red mud storage, realize resource utilization of industrial waste, and meet the requirements of sustainable development.

[0034] 2. After reasonable proportioning and processing, it has high strength, can meet the requirements of road base for bearing capacity, provide stable support for the road, and ensure the stability of the road under vehicle load. At the same time, it can replace traditional cement and other materials, reduce resource consumption and carbon emissions in the cement production process, and help alleviate the impact of greenhouse gas emissions on the environment.

[0035] 3. Red mud is an industrial waste with a wide source and low cost. Using it as a road base material can make the subsequent maintenance costs of the road relatively low after its completion, saving the full life cycle cost of the road. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart for preparing a fully red mud-based stabilized crushed stone lightweight mixture suitable for road base. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit the present invention.

[0038] Example 1

[0039] A fully red mud-based stabilized crushed stone lightweight mixture suitable for road base comprises the following components in parts by mass: 50 parts of a burnt red mud coarse aggregate component, 20 parts of a burnt red mud fine aggregate component, and 12 parts of a red mud-based binder component.

[0040] Among them, the particle sphericity of the burned red mud coarse aggregate component is 0.6, the flattening rate is 0.45, and the particle sizes of 20mm-30mm, 10mm-20mm, and 5mm-10mm account for 16%, 55%, and 32% respectively; the 0.3mm sieve hole passing rate of the burned red mud fine aggregate is 72%; the red mud-based cementing material includes 8 parts of red mud, 1 part of activator, 1 part of reinforcing agent, and 2 parts of water. The SiO 2 The content is 20wt%, the CaO content is 28wt%, and the water content is 0.32wt%; the activator is a sodium silicate solution with a mass concentration of 20wt%, and the reinforcing agent is a sulfonated melamine formaldehyde resin.

[0041] The preparation process is as follows:

[0042] a. First, the red mud was mechanically dried and placed in an oven at 110°C for 8 hours and stored at room temperature. The moisture content of the red mud was 0.32wt%, SiO 2 The content is 20wt%, and the CaO content is 28wt%.

[0043] b. Put the red mud into the disc ball forming machine, set the disc speed to 5r / min, add an appropriate amount of water to spray and humidify during the rotation of the disc, so that the red mud gradually forms a state with a certain plasticity, and the disc ball forming method is used to make red mud balls with relatively uniform size and regular shape.

[0044] c. Place the red mud pellets in a rotary kiln for firing at 1000°C for 2 hours, then cool them to room temperature using a ventilation cooling device to obtain the finished product, which is then sieved to obtain the fired red mud coarse aggregate and fired red mud fine aggregate. The aggregate bulk density is tested to be 1050kg / m 3 , cylinder pressure strength 5.5Mpa.

[0045] d. Put 8 parts of red mud and 1 part of sodium silicate solution into a ball mill, and ball mill at a speed of 200r / min for 5 minutes to form a uniform mixture. Then add 2 parts of water and 1 part of sulfonated melamine formaldehyde resin in proportion, put it into a high-powered mixer and stir for 3 minutes to prepare a red mud-based binder.

[0046] e. The above 50 parts of burned red mud coarse aggregate, 20 parts of burned red mud fine aggregate and 12 parts of red mud-based binder are mixed evenly by a mixer to obtain the fully red mud-based stabilized crushed stone lightweight mixture suitable for road base.

[0047] The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base was loaded into a test mold, and a film was covered on the surface of the test mold for 24 hours after molding. After demolding, the test piece was cured at 20°C, and the bulk density, rebound modulus and 7d unconfined compressive strength of the mixture were tested as shown in Table 1 below.

[0048] Table 1 Performance of all-red mud-based stabilized crushed stone lightweight mixture for road base

[0049] Detection indicators Test results <![CDATA[Bulk density kg / m 3 > 1126 Rebound modulus / MPa 320 7d unconfined compressive strength / MPa 3.5

[0050] Example 2

[0051] A fully red mud-based stabilized crushed stone lightweight mixture suitable for road base comprises the following components in parts by mass: 60 parts of a burnt red mud coarse aggregate component, 30 parts of a burnt red mud fine aggregate component, and 18 parts of a red mud-based binder component.

[0052] Among them, the particle sphericity of the burned red mud coarse aggregate component is 0.7, the flattening rate is 0.36, and the particle sizes of 20mm-30mm, 10mm-20mm, and 5mm-10mm account for 21%, 52%, and 35% respectively; the 0.3mm sieve hole passing rate of the burned red mud fine aggregate is 77%; the red mud-based cementing material includes 9 parts of red mud, 3 parts of activator, 3 parts of reinforcing agent, and 3 parts of water. The SiO 2 The content is 23wt%, the CaO content is 31wt%, and the water content is 0.26wt%; the activator is a sodium silicate solution with a mass concentration of 18wt%, and the reinforcing agent is a sulfonated melamine formaldehyde resin.

[0053] The preparation process is as follows:

[0054] a. First, the red mud was mechanically dried and placed in an oven at 110°C for 8 hours and stored at room temperature. The moisture content of the red mud was 0.26wt%, SiO 2 The content is 23wt%, and the CaO content is 31wt%.

[0055] b. Put the red mud into the disc ball forming machine, set the disc speed to 10r / min, add appropriate amount of water for water spraying and humidification during the rotation of the disc, so that the red mud gradually forms a state with a certain plasticity, and the red mud balls with relatively uniform size and regular shape are made through the disc ball forming method.

[0056] c. Place the red mud pellets in a rotary kiln for firing at 1100°C for 3 hours, then cool them to room temperature using a ventilation cooling device to obtain the finished product, which is then sieved to obtain the fired red mud coarse aggregate and fired red mud fine aggregate. The aggregate bulk density is tested to be 1106kg / m 3 , cylinder pressure strength 5.8Mpa.

[0057] d. Put 9 parts of red mud and 3 parts of sodium silicate solution into a ball mill, and ball mill them at a speed of 250r / min for 6 minutes to form a uniform mixture. Then add 3 parts of water and 3 parts of sulfonated melamine formaldehyde resin in proportion, put it into a high-powered mixer and stir it for 4 minutes to make a red mud-based binder.

[0058] e. The above 60 parts of burned red mud coarse aggregate, 30 parts of burned red mud fine aggregate and 18 parts of red mud-based binder are mixed evenly by a mixer to obtain the fully red mud-based stabilized crushed stone lightweight mixture suitable for road base.

[0059] The all-red mud-based stabilized gravel lightweight mixture suitable for road base was loaded into a test mold, and a film was covered on the surface of the test mold for 24 hours after molding. After demolding, the test piece was cured at 20°C. The bulk density, rebound modulus and 7d unconfined compressive strength of the mixture were tested and are shown in Table 2 below.

[0060] Table 2 Performance of all-red mud-based stabilized crushed stone lightweight mixture for road base

[0061] Detection indicators Test results <![CDATA[Bulk density kg / m 3 > 1149 Rebound modulus / MPa 375 7d unconfined compressive strength / MPa 3.3

[0062] Example 3

[0063] A fully red mud-based stabilized crushed stone lightweight mixture suitable for road base comprises the following components in parts by mass: 70 parts of a burnt red mud coarse aggregate component, 40 parts of a burnt red mud fine aggregate component, and 20 parts of a red mud-based binder component.

[0064] Among them, the particle sphericity of the burned red mud coarse aggregate component is 0.8, the flattening rate is 0.28, and the particle sizes of 20mm-30mm, 10mm-20mm, and 5mm-10mm account for 24%, 61%, and 33% respectively; the 0.3mm sieve hole passing rate of the burned red mud fine aggregate is 75%; the red mud-based cementing material includes 12 parts of red mud, 2 parts of activator, 2 parts of reinforcing agent, and 4 parts of water. The SiO 2 The content is 18wt%, the CaO content is 29wt%, and the water content is 0.21wt%; the activator is 19wt% sodium silicate solution, and the reinforcing agent is sulfonated melamine formaldehyde resin.

[0065] The preparation process is as follows:

[0066] a. First, the red mud was mechanically dried and placed in an oven at 110°C for 8 hours and stored under dry and room temperature conditions. The moisture content of the red mud was 0.21wt%, SiO 2 The content is 18wt%, and the CaO content is 29wt%.

[0067] b. Put the red mud into the disc ball forming machine, set the disc speed to 20r / min, add an appropriate amount of water to spray and humidify during the rotation of the disc, so that the red mud gradually forms a state with a certain plasticity, and the disc ball forming method is used to make red mud balls with relatively uniform size and regular shape.

[0068] c. Put the red mud balls into a rotary kiln for firing at 1200℃ for 4 hours, then cool them to room temperature using a ventilation cooling device to obtain the finished product, and then screen them to obtain fired red mud coarse aggregate and fired red mud fine aggregate. The aggregate bulk density is tested to be 1118kg / m3 and the cylinder pressure strength is 5.6Mpa.

[0069] d. Put 12 parts of red mud and 2 parts of sodium silicate solution into a ball mill, and ball mill at 300r / min for 8 minutes to form a uniform mixture. Then add 4 parts of water and 2 parts of sulfonated melamine formaldehyde resin in proportion, put it into a high-powered mixer and stir it for 5 minutes to make a red mud-based binder.

[0070] e. The above 70 parts of burned red mud coarse aggregate, 40 parts of burned red mud fine aggregate and 20 parts of red mud-based binder are mixed evenly by a mixer to obtain the fully red mud-based stabilized crushed stone lightweight mixture suitable for road base.

[0071] The all-red mud-based stabilized gravel lightweight mixture suitable for road base was loaded into a test mold, and a film was covered on the surface of the test mold for 24 hours after molding. After demolding, the test piece was cured at 20°C, and the bulk density, rebound modulus and 7d unconfined compressive strength of the mixture were tested as shown in Table 3 below.

[0072] Table 3 Performance of all-red mud-based stabilized crushed stone lightweight mixture for road base

[0073] Detection indicators Test results <![CDATA[Bulk density kg / m 3 > 1196 Rebound modulus / MPa 392 7d unconfined compressive strength / MPa 3.4

[0074] It can be found that the prepared all-red mud-based stabilized crushed stone lightweight mixture suitable for road base has excellent properties and a bulk density of less than 1200kg / m 3 , the modulus of resilience is greater than 300MPa, and the 7d unconfined compressive strength is greater than 3MPa. In addition, the all-red mud-based stabilized crushed stone lightweight mixture suitable for road base of the present invention is mainly prepared from industrial solid waste material red mud, and the economic, social and environmental benefits brought by it are quite outstanding.

[0075] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A fully red mud-based stabilized crushed stone lightweight mixture suitable for road base, characterized in that: The composition includes the following components in parts by weight: Burnt red mud coarse aggregate component: 50-70 parts; Burnt red mud fine aggregate component: 20-40 parts; Red mud-based binder component: 12-20 parts.

2. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 1, characterized in that: The fired red mud coarse aggregate component and the fired red mud fine aggregate component are both made from red mud by a disc ball forming method to form red mud balls with uniform size and regular shape; they are calcined at 1000-1200°C for 2-4 hours and then cooled to room temperature by a ventilation cooling device.

3. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 1, characterized in that: The burnt red mud coarse aggregate component has a particle sphericity between 0.6 and 0.8, a flattening rate less than 0.5, and a particle size distribution as follows: 20mm-30mm: 16%-24%; 10mm-20mm: 52%-61%; 5mm-10mm:32%-35%.

4. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 1, characterized in that: In the burnt red mud fine aggregate component, the pass rate of the burnt red mud through a 0.3 mm sieve hole is greater than 65%.

5. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 1, characterized in that: The red mud-based cementing material comprises the following components in parts by mass: Red mud: 8-12 parts; Activator: 1-3 parts; Enhancer: 1-3 parts; Water: 2-4 parts.

6. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 5, characterized in that: In the red mud-based cementing material component, the SiO2 content in the red mud is greater than 15wt%, the CaO content is greater than 25wt%, and the water content is less than 0.5wt%.

7. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 5, characterized in that: The activator is an activator sodium silicate solution.

8. The all-red mud-based stabilized crushed stone lightweight mixture suitable for road base according to claim 5, characterized in that: The reinforcing agent is sulfonated melamine formaldehyde resin.

9. The method for preparing a fully red mud-based stabilized crushed stone lightweight mixture suitable for a road base according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. First, the red mud is mechanically dried, the red mud raw material is placed in an oven at 110°C for 8 hours, and stored under dry and room temperature conditions. The moisture content in the test value is required to be less than 0.5wt%, the SiO2 content of the red mud is greater than 15wt%, and the CaO content is greater than 25wt%; S2. Put the red mud into a disc ball forming machine, set the disc speed between 5-20r / min, add water to the disc during the rotation of the disc for water spraying and humidification, so that the red mud gradually forms a state with a certain plasticity, and the disc ball forming method is used to make red mud balls with relatively uniform size and regular shape; S3. Place the red mud pellets in a rotary kiln for firing at 1000-1200°C for 2-4 hours, then cool them to room temperature using a ventilation cooling device to obtain a finished product, and then screen them to obtain fired red mud coarse aggregate and fired red mud fine aggregate; the aggregate bulk density is required to be less than 1200kg / m 3 , cylinder pressure strength is greater than 5Mpa; S4. Put the red mud and activator into a ball mill in proportion, mill at a speed of 200-300r / min for 5-8min to form a uniform mixture, then add water and enhancer in proportion, put into a high-powered mixer and stir for 3-5min to form a red mud-based cementing material; S5. The burned red mud coarse aggregate, burned red mud fine aggregate and red mud-based binder material are mixed uniformly by a mixer to obtain the fully red mud-based stabilized gravel lightweight mixture suitable for the road base; The obtained all-red mud-based stabilized crushed stone lightweight mixture suitable for road base has a bulk density of less than 1200kg / m 3 , the rebound modulus is greater than 300MPa, and the 7d unconfined compressive strength is greater than 3MPa.

Images