CN115403312B - High-sulfur tailing cementing material and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of sulfur-containing tailing recycling, and particularly discloses a high-sulfur tailing cementing material and a preparation method and application thereof. The high-sulfur tailing cementing material comprises the following raw material components in parts by weight: 200-220 parts of cement, 70-90 parts of fly ash, 40-60 parts of high-sulfur tailing, 40-60 parts of mineral powder, 6-8 parts of limestone powder, 6-12 parts of barium salt, 13-15 parts of modified bentonite, 7-13 parts of activated alumina and 3-5 parts of an exciting agent. The high-sulfur tailing cementing material provided by the invention has scientific compatibility, can reduce the sulfate ion concentration in the concrete containing the high-sulfur tailings, prevent expansion damage caused by crystallization of secondary gypsum, ettringite and the like, effectively improve the internal structure of the concrete, and achieve the purposes of improving the strength, compactness and durability of the concrete.

Description

A kind of high-sulfur tailings cementitious material and its preparation method and application

technical field

The invention relates to the technical field of resource utilization of sulfur-containing tailings, in particular to a high-sulfur tailings cementitious material and its preparation method and application.

Background technique

Tailings are industrial solid wastes produced in the process of ore dressing and smelting. The quantity is huge, and its large accumulation will cause environmental pollution and even secondary geological disasters such as tailings pond dam breaks and landslides. It is a major source of danger and pollution. Therefore, the resource utilization of tailings has become the consensus of all sectors of society, and it is also the key direction of the recycling of industrial solid waste resources in my country.

In the prior art, high-sulfur metal tailings are used as admixtures in the preparation of concrete, which can not only achieve the purpose of consuming a large amount of tailings, but also reduce the amount of cement in concrete, save energy and reduce emissions, and alleviate the shortage of mineral admixtures such as fly ash and slag. However, the tailings produced by metal ores usually contain high sulfides, which react with cement hydration products to form expansion phase products such as ettringite and secondary gypsum, which have strong adsorption capacity and can generate great expansion stress, leading to the generation and expansion of micro-cracks inside the concrete. Therefore, how to solve the problem that the addition of high-sulfur tailings will cause irregular cracks in concrete and reduce the compressive strength and corrosion resistance of concrete is still a difficult point in the development of sulfur-containing tailings resource utilization technology.

Contents of the invention

In order to overcome the problems in the prior art that the addition of high-sulfur tailings will cause irregular cracks in concrete and reduce the compressive strength and corrosion resistance of concrete, the present invention provides a high-sulfur tailings cementitious material, which can reduce the concentration of sulfate ions in concrete containing high-sulfur tailings, prevent expansion damage caused by crystallization of secondary gypsum and ettringite, effectively improve the internal structure of concrete, and achieve the purpose of increasing the strength, compactness and durability of concrete.

And, the present invention also provides a preparation method of the above-mentioned high-sulfur tailings cementitious material.

And, the present invention also provides high-sulfur tailings concrete prepared by using the above-mentioned high-sulfur tailings cementitious material, the internal structures of which are bonded to each other and not easy to separate from each other, and have better working performance than ordinary concrete.

And, the present invention also provides a method for preparing the above-mentioned high-sulfur tailings concrete.

In order to achieve the above-mentioned purpose of the invention, the present invention has adopted following technical scheme:

In a first aspect, the present invention provides a high-sulfur tailings cementitious material, comprising the following raw material components in parts by weight: 200-220 parts of cement, 70-90 parts of fly ash, 40-60 parts of high-sulfur tailings, 40-60 parts of mineral powder, 6-8 parts of limestone powder, 6-12 parts of barium salt, 13-15 parts of modified bentonite, 7-13 parts of activated alumina and 3-5 parts of activator; 1.5: 2.1～2.5: 2.0～2.4 composed of barium chloride, barium hydroxide and barium nitrate.

Compared with the prior art, the high-sulfur tailings cementitious material provided by the present invention utilizes the active effect and filling effect of fly ash, limestone powder, mineral powder and high-sulfur tailings to modify and strengthen concrete, which can effectively improve the internal structure of concrete and achieve the purpose of improving the strength, compactness and durability of concrete, and through the compound use of barium salt, modified bentonite, activated alumina, activator and the above-mentioned powders, it can solidify sulfate ions intruded into concrete, effectively preventing secondary gypsum, ettringite, etc. Expansion and destruction, and refine the concrete pore size, greatly improve the comprehensive performance of concrete, prolong the service life of concrete, and enhance the safety of concrete engineering. At the same time, the present invention uses barium chloride, barium hydroxide and barium nitrate in combination to effectively solidify the sulfate ions that have invaded the interior of the concrete, thereby forming barium sulfate crystals and filling the micro-cracks inside the concrete, greatly improving the sulfate erosion resistance of the concrete, and the optimal ratio of each component of the barium salt has a stronger adsorption effect on sulfate ions, and significantly improves the sulfate erosion resistance of the concrete. The fly ash, limestone powder, slag powder and high-sulfur tailings selected for the high-sulfur tailings cementitious material provided by the invention are all industrial wastes, which not only saves production costs, but also realizes the secondary utilization of wastes, which is of great significance to the protection of the ecological environment.

The fly ash is a substance mainly composed of activated silica, activated alumina _and activated calcium oxide, which can convert the unfavorable calcium hydroxide into a favorable CSH gel (volcanic ash effect), that is, the glassy activated silica and alumina in the fly ash interact with calcium hydroxide in the cement to generate calcium silicate hydrate and calcium aluminate hydrate, which fills the gap between the cement. On the one hand, the strength and compactness of the concrete are increased, and the impermeability is improved. Chance of damage to concrete.

The high-sulfur tailings not only have a certain gelling effect on concrete, but also can make full use of its small particle size to evenly fill the gaps between the aggregates, making the inner skeleton of the concrete more compact.

The ore powder is the blast furnace waste slag from the steelmaking plant that has been quenched and ground to a certain fineness requirement, and has calcium oxide and alumina as the main components. It has good morphological effect, micro-aggregate effect and pozzolanic effect, and can improve the hydration mechanism of cementitious materials and the microstructure of concrete, refine the concrete pore size, and increase the total proportion of harmless pores and less harmful pores. After hydration, it can generate granular sodium calcium aluminosilicate hydrate minerals, CSH gel and a small amount of amorphous gel substances, which can fill the pores of the concrete interface and make the concrete structure more compact.

The limestone powder has the function of filling and dispersing in the concrete, and by optimizing the particle gradation, the workability and water retention of the freshly mixed concrete can be improved, and the impermeability and durability of the hardened concrete can be improved. In addition, limestone powder can deposit calcium hydroxide, act as a crystal nucleus, accelerate the hydration of cement particles, improve the early strength of concrete, and thus improve the resistance of concrete to sulfate attack.

Although the addition of high-sulfur tailings will introduce sulfide, the corrosion reactions of formula (1), formula (2) and formula (3) will occur, and expansive products such as ettringite and secondary gypsum will be generated, which will lead to the generation and expansion of micro-cracks, loose structure, and deterioration of the service performance of concrete. However, by adding a certain amount of barium salt, modified bentonite, activated alumina and activator into the high-sulfur tailings cementitious material, the inventors were able to fix the sulfate ions that invaded the concrete pore network in the form of barium sulfate. Although ettringite was still produced, its amount was significantly reduced. The reason may be that _the reactions of formula ⁽ 3) and formula (4) occurred in concrete at the same time, _and the solubility ^of barium sulfate is lower than that of calcium sulfate. Therefore, SO ₄ ^2- intruded into concrete reacts with Ba ²⁺ ions first to form barium sulfate. Its specific reaction process is:

Ca(OH) ₂ +SO ₄ ^2- +2H ₂ O→CaSO ₄ 2H ₂ O+ ^2OH- (1);

_Na2SO4 · _10H2O +Ca(OH) ₂ → _CaSO4 · _2H2O +2NaOH+ _8H2O (2) _;

3(CaSO ₄ ·2H ₂ O)+3CaO·Al ₂ O ₃ ·6H ₂ O+19H ₂ O→3CaO·Al ₂ O ₃ ·3CaSO ₄ ·31H ₂ O(3);

Ba(OH) ₂ +Na ₂ SO ₄ →BaSO ₄ +2NaOH (4).

Optionally, the cement is P.O42.5 Portland cement with a density of 3.06g/cm ³ -3.12g/cm ³ .

Optionally, the fly ash is secondary fly ash.

Optionally, the particle size of the high-sulfur tailings ranges from 10 μm to 75 μm.

Optionally, the specific surface area of the mineral powder is 400m ² /Kg-450m ² /Kg.

Optionally, the specific surface area of the limestone powder is >700m ² /Kg.

The preferred compounding of fly ash, high-sulfur tailings, slag powder and limestone powder exerts strong pozzolanic activity and filling effect in the cementitious system, effectively improves the microstructure of concrete, forms a solid concrete support structure, and significantly improves the mechanical properties of concrete in all aspects; at the same time, the specific mass ratio can ensure that the prepared concrete has good fluidity, water retention and cohesion.

Optionally, the specific surface area of the activated alumina is 409.03m ² /g-440.10m ² /g.

The preferred activated alumina can promote the rapid reaction of substances in cement to form ettringite, reduce the content of calcium hydroxide, accelerate the hydration of C ₃ S, and further improve the strength of concrete; at the same time, it has a synergistic effect with barium salt, modified bentonite and activator. When mixed in an appropriate proportion, it can increase the compactness and strength of concrete, thereby prolonging the service life of concrete.

Optionally, the activator is sodium hydroxide.

Optionally, the preparation method of the modified bentonite is: activate the bentonite at 500°C-550°C for 2.5h-3.0h, then mix it with calcium oxide at a mass ratio of 3.2-3.3:1-1.1, and grind until the specific surface area reaches 340m ² /Kg-370m ² /Kg to obtain the modified bentonite.

The preferred modified bentonite is fully activated by roasting and calcium oxide grinding. It has a larger interlayer distance and specific surface area, and the adsorption effect is enhanced. It can effectively adsorb sulfate ions, and the montmorillonite in the bentonite will participate in the hydration reaction of cement and interweave with ettringite to form a denser structure with fewer pores and improve the mechanical properties of the cementitious material. At the same time, the present invention combines the modified bentonite and the activator to form a composite excitation system, which can stimulate the fly ash and mineral powder components with low chemical activity, realize the activation of the chemical properties of the fly ash and mineral powder, and synergistically improve the compactness and corrosion resistance of the material, and have good water absorption and water retention, maintain the hydration environment required by the cementitious material, and ensure the improvement of the strength of the concrete in the later stage.

In a second aspect, the present invention provides a method for preparing the above-mentioned high-sulfur tailings cementitious material, comprising the following steps:

(1) According to the weight ratio, the modified bentonite and the activator are mixed and then ground to obtain a powder with a specific surface area of 400m ² /Kg-450m ² /Kg;

(2) uniformly mixing the powder with the cement, fly ash, high-sulfur tailings, mineral powder, limestone powder, barium salt and activated alumina to obtain the high-sulfur tailings cementitious material.

In the third aspect, the present invention provides a high-sulfur tailings concrete, comprising 400-500 parts of the above-mentioned high-sulfur tailings cementitious material, 950-1000 parts of coarse aggregate, 750-800 parts of fine aggregate, 145-155 parts of water and 12-14 parts of water reducer.

Compared with the prior art, the high-sulfur tailings concrete provided by the present invention can form a cementitious structure system with almost no pores through the interaction of coarse aggregate, fine aggregate, high-sulfur tailings cementitious material and water reducing agent, greatly enhance the strength of concrete, make the internal structure of concrete bonded to each other and not easy to separate from each other, and has better working performance compared with ordinary concrete. At the same time, the present invention uses high-sulfur tailings as an admixture in the preparation of concrete, realizes secondary utilization of tailings solid waste, can reduce the amount of cement used in single concrete, solves the problem of insufficient supply of grade I and II fly ash, reduces the cost of single concrete by 6% to 10%, and avoids the phenomenon of low concrete strength caused by high-sulfur tailings as cemented filling aggregates, which is of great significance for the construction of green mines and the sustainable development of mineral resources.

Optionally, the coarse aggregate is continuously graded gravel with a particle size of 5 mm to 20 mm.

Optionally, the fine aggregate is river sand with a fineness modulus of 2.7-3.0 and an apparent density of 2520kg/m ³ -2620kg/m ³ .

The preferred coarse aggregate, fine aggregate and high-sulfur tailings can effectively form a gradation, which helps to improve the bearing performance of the entire concrete, makes the entire concrete structure dense and hard, and helps to improve the compressive strength of the concrete.

Optionally, the water reducer is a polycarboxylate water reducer with a solid content of 35% to 40% and a water reducing rate of 31% to 32.1%.

The preferred water reducing agent helps to reduce the water-cement ratio, can meet the workability requirements of concrete, and further makes the concrete reach a self-compacting state, which is convenient for construction.

In a fourth aspect, the present invention provides a method for preparing the above-mentioned high-sulfur tailings concrete, comprising the steps of:

(1) by weight ratio, the coarse aggregate and the fine aggregate are uniformly mixed to obtain materials;

(2) Mix and stir the preparation, the high-sulfur tailings cementitious material and water for the first time at a speed of 300r/min to 350r/min, let stand for 30s to 60s, then add the water reducing agent, and perform the second mixing and stirring at a speed of 300r/min to 350r/min to obtain the high-sulfur tailings concrete.

Optionally, in step (2), the mixing and stirring time for the first time is 1 min to 2 min, and the mixing and stirring time for the second time is 3 min to 4 min.

The preferred batch mixing method can evenly coat the surface of the aggregate with a film of cementitious material, improve the micro-crack defects of the aggregate, improve the compactness, and then enhance the frost resistance, impermeability and erosion resistance of the concrete, greatly reduce the risk of concrete cracking, and improve the strength of the concrete.

In summary, a high-sulfur tailings cementitious material provided by the present invention and its preparation method and application have the following beneficial effects:

(1) The present invention mixes fly ash, high-sulfur tailings, slag and limestone powder into high-sulfur tailings concrete to exert strong pozzolanic activity and filling effect, effectively improve the microstructure of concrete, form a cementitious structure system with almost no pores, significantly enhance the mechanical properties of concrete, greatly reduce the risk of early cracking of concrete, and through the synergistic effect of barium salt, modified bentonite, activated alumina and activators, effectively solidify the sulfate ions that invade the interior of the concrete, greatly improve the sulfate erosion resistance of concrete, and improve the concrete. Density and strength, thereby prolonging the service life of concrete.

(2) The preparation method of the high-sulfur tailings cementitious material provided by the present invention has simple material processing and production technology, and a large amount of industrial wastes such as fly ash, limestone powder, mineral powder and high-sulfur tailings are used. The fly ash, limestone powder, mineral powder and high-sulfur tailings selected for the high-sulfur tailings cementitious material provided by the present invention are all industrial wastes, which not only saves production costs, can reduce the amount of cement in concrete, but also realizes secondary utilization of waste, which has significant economic, social and environmental benefits.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

This embodiment provides a high-sulfur tailings cementitious material, including the following raw material components in parts by weight: 200 parts of cement, 70 parts of fly ash, 40 parts of high-sulfur tailings, 40 parts of mineral powder, 6 parts of limestone powder, 6 parts of barium salt, 13 parts of modified bentonite, 7 parts of activated alumina and 3 parts of activator.

Among them, the barium salt is composed of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.2:2.1:2.0; the fly ash is secondary fly ash; the particle size of high-sulfur tailings is 10 μm to 75 μm; the specific surface area of mineral powder is 400m²/Kg～450m²/Kg; specific surface area of limestone powder > 700m²/Kg; the specific surface area of activated alumina is 409.03m²/g～440.10m²/g; the activator is sodium hydroxide; the preparation method of modified bentonite is: activate bentonite at 500°C for 2.5h, then mix it with calcium oxide at a mass ratio of 3.3:1, and grind until the specific surface area reaches 340m²/Kg～370m²/Kg to obtain modified bentonite.

This embodiment also provides a preparation method of the above-mentioned high-sulfur tailings cementitious material, the preparation method comprising the following process steps:

(1) According to the weight ratio, the modified bentonite and the activator are mixed and then ground to obtain a powder with a specific surface area of 400m ² /Kg-450m ² /Kg;

(2) Mix the above powder with cement, fly ash, high-sulfur tailings, mineral powder, limestone powder, barium salt and activated alumina to obtain high-sulfur tailings cementitious material.

Example 2

This embodiment provides a high-sulfur tailings cementitious material, including the following raw material components in parts by weight: 220 parts of cement, 90 parts of fly ash, 60 parts of high-sulfur tailings, 60 parts of mineral powder, 8 parts of limestone powder, 12 parts of barium salt, 15 parts of modified bentonite, 13 parts of activated alumina and 5 parts of activator.

Among them, the barium salt is a mixture of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.5:2.5:2.4; the fly ash is a secondary fly ash; the particle size of the high-sulfur tailings is 10 μm to 75 μm; the specific surface area of the mineral powder is 400m²/Kg～450m²/Kg; specific surface area of limestone powder > 700m²/Kg; the specific surface area of activated alumina is 409.03m²/g～440.10m²/g; the activator is sodium hydroxide; the preparation method of modified bentonite is: activate bentonite at 550°C for 3.0h, then mix it with calcium oxide at a mass ratio of 3.2:1.1, and grind until the specific surface area reaches 340m²/Kg～370m²/Kg to obtain modified bentonite.

This embodiment also provides a preparation method of the above-mentioned high-sulfur tailings cementitious material, the preparation method comprising the following process steps:

(1) According to the weight ratio, the modified bentonite and the activator are mixed and then ground to obtain a powder with a specific surface area of 400m ² /Kg-450m ² /Kg;

(2) Mix the above powder with cement, fly ash, high-sulfur tailings, mineral powder, limestone powder, barium salt and activated alumina to obtain high-sulfur tailings cementitious material.

Example 3

This embodiment provides a high-sulfur tailings cementitious material, including the following raw material components in parts by weight: 210 parts of cement, 80 parts of fly ash, 50 parts of high-sulfur tailings, 50 parts of mineral powder, 7 parts of limestone powder, 9 parts of barium salt, 14 parts of modified bentonite, 10 parts of activated alumina and 4 parts of activator.

Among them, the barium salt is a mixture of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.3:2.3:2.2; the fly ash is a secondary fly ash; the particle size of the high-sulfur tailings is 10 μm to 75 μm; the specific surface area of the mineral powder is 400m²/Kg～450m²/Kg; specific surface area of limestone powder > 700m²/Kg; the specific surface area of activated alumina is 409.03m²/Kg～440.10m²/g; the activator is sodium hydroxide; the preparation method of modified bentonite is: activate bentonite at 530°C for 2.8h, then mix it with calcium oxide at a mass ratio of 3.3:1.1, and grind until the specific surface area reaches 340m²/Kg～370m²/Kg to obtain modified bentonite.

This embodiment also provides a preparation method of the above-mentioned high-sulfur tailings cementitious material, the preparation method comprising the following process steps:

(1) According to the weight ratio, the modified bentonite and the activator are mixed and then ground to obtain a powder with a specific surface area of 400m ² /Kg-450m ² /Kg;

(2) Mix the above powder with cement, fly ash, high-sulfur tailings, mineral powder, limestone powder, barium salt and activated alumina to obtain high-sulfur tailings cementitious material.

Example 4

This example provides a high-sulfur tailings concrete, including the following raw material components in parts by weight: 400 parts of high-sulfur tailings cementitious material prepared in Example 1, 950 parts of coarse aggregate, 750 parts of fine aggregate, 145 parts of water and 12 parts of water reducer.

Among them, the coarse aggregate is continuously graded crushed stone with a particle size of 5mm-20mm; the fine aggregate is river sand with a fineness modulus of 2.7-3.0 and an apparent density of 2520kg/ ^m3-2620kg / ^m3 ; the water reducer is polycarboxylate water reducer.

This embodiment also provides a method for preparing the above-mentioned high-sulfur tailings concrete, the preparation method comprising the following process steps:

(1) According to the weight ratio, the coarse aggregate and the fine aggregate are evenly mixed to obtain raw materials;

(2) Mix and stir the above materials, high-sulfur tailings cementitious material and water at a speed of 300r/min for 1min, let stand for 30s, then add a water reducer, and mix and stir again at a speed of 300r/min for 3min to obtain high-sulfur tailings concrete.

Example 5

This example provides a high-sulfur tailings concrete, including the following raw material components in parts by weight: 500 parts of high-sulfur tailings cementitious material prepared in Example 2, 1000 parts of coarse aggregate, 800 parts of fine aggregate, 155 parts of water and 14 parts of water reducer.

Among them, the coarse aggregate is continuously graded crushed stone with a particle size of 5mm-20mm; the fine aggregate is river sand with a fineness modulus of 2.7-3.0 and an apparent density of 2520kg/ ^m3-2620kg / ^m3 ; the water reducer is polycarboxylate water reducer.

This embodiment also provides a method for preparing the above-mentioned high-sulfur tailings concrete, the preparation method comprising the following process steps:

(1) According to the weight ratio, the coarse aggregate and the fine aggregate are evenly mixed to obtain raw materials;

(2) Mix and stir the above-mentioned materials, high-sulfur tailings cementitious material and water at a speed of 350r/min for 2 minutes, let stand for 60s, then add a water reducer, and mix and stir again at a speed of 350r/min for 4 minutes to obtain high-sulfur tailings concrete.

Example 6

This example provides a high-sulfur tailings concrete, which includes the following raw material components in parts by weight: 450 parts of high-sulfur tailings cementitious material prepared in Example 3, 980 parts of coarse aggregate, 780 parts of fine aggregate, 150 parts of water and 13 parts of water reducing agent.

Among them, the coarse aggregate is continuously graded gravel with a particle size of 5mm-20mm; the fine aggregate is river sand with a fineness modulus of 2.7-3.0 and an apparent density of 2520kg/ ^m3-2620kg / ^m3 ; the water reducer is polycarboxylate water reducer.

This embodiment also provides a method for preparing the above-mentioned high-sulfur tailings concrete, the preparation method comprising the following process steps:

(1) According to the weight ratio, the coarse aggregate and the fine aggregate are evenly mixed to obtain raw materials;

(2) Mix and stir the above materials, high-sulfur tailings cementitious material and water at a speed of 330r/min for 1.5min, let stand for 45s, then add a water reducer, and mix and stir at a speed of 320r/min for 3.5min to obtain high-sulfur tailings concrete.

Comparative example 1

This comparative example provides a high-sulfur tailings concrete, the composition of its raw materials and the preparation method are the same as in Example 4, the difference is that the amount of barium salt added to 1 part of high-sulfur tailings cementitious material is 18 parts.

Comparative example 2

This comparative example provides a high-sulfur tailings concrete, the composition of its raw materials and the preparation method are the same as in Example 4, the difference is that the barium salt is composed of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.2:6:2.0.

Comparative example 3

This comparative example provides a high-sulfur tailings concrete, the composition of its raw materials and the preparation method are the same as those of Example 4, the difference is that the modified bentonite is replaced by kaolin.

In order to prove the effect of the high-sulfur tailings concrete prepared by the embodiments of the present invention and comparative examples, the high-sulfur tailings concrete in Examples 4-6 and Comparative Examples 1-3 are tested according to the national standard method, and the test results are shown in the following table:

Table 1 Concrete Performance Test Experimental Results

It can be seen from the above table that the density and strength of the high-sulfur tailings concrete provided by the present invention are significantly increased after adding the high-sulfur tailings cementitious material, effectively improving the sulfate erosion resistance, good fluidity and slump retention, achieving the purpose of improving the safety and durability of concrete, and the preparation cost is low, realizing the secondary utilization of solid waste, and solving the problem of low concrete strength caused by high-sulfur tailings as cemented filling aggregate.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement or improvement made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A high-sulfur tailings cementitious material, characterized in that: the raw material components comprising the following parts by weight: 200-220 parts of cement, 70-90 parts of fly ash, 40-60 parts of high-sulfur tailings, 40-60 parts of mineral powder, 6-8 parts of limestone powder, 6-12 parts of barium salt, 13-15 parts of modified bentonite, 7-13 parts of activated alumina and 3-5 parts of activator; 1.5: 2.1～2.5: 2.0～2.4 composed of barium chloride, barium hydroxide and barium nitrate; The preparation method of the modified bentonite is as follows: activate the bentonite at 500°C-550°C for 2.5h-3.0h, then mix it with calcium oxide at a mass ratio of 3.2-3.3:1-1.1, and grind until the specific surface area reaches 340m ² /Kg-370m ² /Kg to obtain the modified bentonite. 2. The high-sulfur tailings cementitious material as claimed in claim 1, characterized in that: the fly ash is secondary fly ash; and/or The particle size of the high-sulfur tailings is 10 μm to 75 μm; and/or The specific surface area of the mineral powder is 400m ² /Kg-450m ² /Kg. 3. The high-sulfur tailings cementitious material according to claim 1, characterized in that: the specific surface area of the limestone powder is >700m ² /Kg; and/or The specific surface area of the activated alumina is 409.03m ² /g-440.10m ² /g; and/or The activator is sodium hydroxide. 4. The preparation method of the high-sulfur tailings cementitious material according to any one of claims 1 to 3, characterized in that: comprising the following steps: (1) According to the weight ratio, the modified bentonite and the activator are mixed and then ground to obtain a powder with a specific surface area of 400m ² /Kg-450m ² /Kg; (2) uniformly mixing the powder with the cement, fly ash, high-sulfur tailings, mineral powder, limestone powder, barium salt and activated alumina to obtain the high-sulfur tailings cementitious material. 5. A high-sulfur tailings concrete, characterized in that it comprises the high-sulfur tailings cementitious material according to any one of claims 1-3. 6. The high-sulfur tailings concrete according to claim 5, characterized in that: the high-sulfur tailings concrete comprises the following raw material components in parts by weight: 400-500 parts of high-sulfur tailings cementitious material, 950-1000 parts of coarse aggregate, 750-800 parts of fine aggregate, 145-155 parts of water and 12-14 parts of water reducing agent. 7. The high-sulfur tailings concrete according to claim 6, characterized in that: the coarse aggregate is continuously graded crushed stone with a particle size of 5 mm to 20 mm; and/or The fine aggregate is river sand with a fineness modulus of 2.7-3.0 and an apparent density of 2520kg/ ^m3-2620kg / ^m3 ; and/or The water reducer is a polycarboxylate water reducer. 8. the preparation method of the described high sulfur tailings concrete of claim 6 or 7 is characterized in that: comprises the steps: (1) by weight ratio, the coarse aggregate and the fine aggregate are uniformly mixed to obtain raw materials; (2) Mix and stir the materials, the high-sulfur tailings cementitious material and water for the first time at a speed of 300r/min to 350r/min, let stand for 30s to 60s, then add the water reducing agent, and carry out the second mixing and stirring at a speed of 300r/min to 350r/min to obtain the high-sulfur tailings concrete. 9. The preparation method of high-sulfur tailings concrete according to claim 8, characterized in that: in step (2), the time for the first mixing and stirring is 1-2 minutes, and the time for the second mixing and stirring is 3-4 minutes.