CN115403312A - A kind of high-sulfur tailings cementitious material and its preparation method and application - Google Patents

Abstract

The invention relates to the technical field of resource utilization of sulfur-containing tailings, and specifically discloses a cementitious material for high-sulfur tailings, a preparation method and application thereof. The high-sulfur tailings cementitious material includes 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, limestone 6-8 parts of 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. The high-sulfur tailings cementitious material provided by the present invention has scientific compatibility, can reduce the concentration of sulfate ions in concrete containing high-sulfur tailings, prevent expansion damage caused by crystallization of secondary gypsum, ettringite, etc., and effectively improve the internal structure of concrete. To achieve the purpose of improving the strength, compactness and durability of 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 an admixture 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 the concrete, save energy and reduce emissions, and relieve fly ash and slag. Such as the shortage of mineral admixtures. However, the tailings produced by metal ore 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, causing the concrete internal The generation and expansion of micro-cracks and the loose structure will cause obvious expansion of concrete and even crack damage, seriously affecting the safety and durability of concrete materials and structures. Even if the filling body is modified with chemical admixtures, the effect is very limited. 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 the concrete and reduce the compressive strength and corrosion resistance of the concrete, the present invention provides a cementitious material for high-sulfur tailings, which can reduce the amount of high-sulfur tailings. The concentration of sulfate ions in the concrete of sulfur tailings can prevent the expansion damage caused by the crystallization of secondary gypsum and ettringite, effectively improve the internal structure of concrete, and achieve the purpose of improving 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 the 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, and 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; wherein, the barium The salt is composed of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.2-1.5:2.1-2.5:2.0-2.4.

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 The internal structure of concrete can 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 powder, it can reduce the sulfate ion intruded into concrete Solidification can effectively prevent the expansion damage caused by the crystallization of secondary gypsum and ettringite, and refine the concrete pore size, greatly improving the overall performance of concrete, prolonging the service life of concrete, and enhancing 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 invade 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. Moreover, the optimal ratio of each component of the barium salt has a stronger adsorption effect on sulfate ions, and significantly improves the sulfate corrosion resistance of concrete. The fly ash, limestone powder, slag 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 beneficial to the protection of the ecological environment has great significance.

The fly ash is a substance mainly composed of activated silica, activated alumina and activated calcium oxide, which can convert calcium hydroxide, which is unfavorable to concrete, into favorable CSH gel (volcanic ash effect), that is, powder The glassy active silica and alumina in the coal ash interact with the calcium hydroxide in the cement to form calcium silicate hydrate and calcium aluminate hydrate, which fill the gaps in the cement and increase the strength and compactness of the concrete on the one hand. , which improves the impermeability, and on the other hand weakens the chance of damage to concrete caused by the expansion of Ca(OH) ₂ crystals.

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 a kind of material whose main components are calcium oxide and aluminum oxide, and has good shape effect, micro-aggregate effect and volcanic ash. Effect, 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 substance, which can fill the pores of the concrete interface and make the concrete structure more compact.

The limestone powder has the functions of filling and dispersing in concrete, and by optimizing particle gradation, the workability and water retention of freshly mixed concrete can be improved, and excellent properties such as impermeability and durability of 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 microcracks , the structure is loose, which degrades 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 can fix the sulfate ions that invaded the pore network of the concrete in the form of barium sulfate. While ettringite is still produced, its amount is 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, so SO ₄ ^2- that penetrates into concrete reacts with Ba ²⁺ ions first to form barium sulfate. The formation of barium sulfate consumes SO ₄ ^2- , and its deposits fill the capillary pores of concrete, thereby reducing the erosion rate of SO ₄ ^2- and hindering the formation and accumulation of expansive ettringite. 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, mineral powder and limestone powder exerts strong pozzolanic activity and filling effect in the cementitious system, effectively improves the microstructure of concrete, and forms a strong concrete support structure. Significantly improve the mechanical and mechanical properties of concrete in all aspects; at the same time, the specific mass ratio can ensure that the prepared concrete has better 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 can be combined with barium salt, Modified bentonite and activator have a synergistic effect. When mixed in an appropriate proportion, it can improve 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, the modified bentonite is obtained.

The preferred modified bentonite is fully activated by roasting and calcium oxide grinding, has a larger interlayer distance and specific surface area, and the adsorption effect is enhanced, which can effectively adsorb sulfate ions, and the montmorillonite in the bentonite will participate in cement. The hydration reaction interweaves with ettringite to form a denser structure, resulting in fewer pores and improving 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 slag components with low chemical activity, realize the activation of the chemical properties of the fly ash and slag, and synergistically improve the chemical properties of the materials. Density and anti-erosion ability, and has good water absorption and water retention, maintains the hydration environment required for cementitious materials, and ensures the improvement of the strength of 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 a 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 12-14 parts and water reducing agent.

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 reducer , greatly enhance the strength of concrete, so that the internal structure of concrete is bonded to each other and not easy to separate from each other. Compared with ordinary concrete, it has better working performance. The concrete slump can reach 235mm, the diffusion can reach 575mm, and the 28d compression resistance The strength can reach 62.2MPa. At the same time, the present invention uses high-sulfur tailings as an admixture in the preparation of concrete, realizes the secondary utilization of tailings solid waste, can reduce the cement consumption of single concrete, and solves the shortage of class I and II fly ash supply It reduces the cost of concrete by 6% to 10%, and avoids the phenomenon of low concrete strength caused by high-sulfur tailings as cemented filling aggregate, 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 optimal 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, and then add the water reducer, The second mixing and stirring is performed at a speed of 300r/min-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 step-by-step 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 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 powder and limestone powder into high-sulfur tailings concrete, which exerts strong pozzolanic activity and filling effect, effectively improves the microstructure of concrete, and forms almost no The porous cementitious structure system can 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 activator, effectively solidify the sulfate radicals that invade the interior of concrete Ions can greatly improve the sulfate corrosion resistance of concrete, increase the compactness and strength of concrete, and prolong the service life of concrete.

(2) The preparation method of high-sulfur tailings cementitious material provided by the 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, slag powder and high-sulfur tailings selected for the cementitious material of high-sulfur tailings are all industrial waste, which not only saves production costs, can reduce the amount of cement in concrete, but also realizes the secondary utilization of waste, It 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, and 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 is 400m ² /Kg～450m ² /Kg; the specific surface area of limestone powder is >700m ² /Kg; the specific surface area of activated alumina is 409.03m ² /g～440.10m ² /g; the activator is sodium hydroxide; The preparation method of the modified bentonite is as follows: activate the bentonite at 500°C for 2.5 hours, then mix it with calcium oxide at a mass ratio of 3.3:1, and grind until the specific surface area reaches 340m ² /Kg-370m ² /Kg to obtain the modified bentonite. Sexual 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, and 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, barium salt is a mixture of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.5:2.5:2.4; fly ash is secondary fly ash; the particle size of high-sulfur tailings is 10 μm to 75 μm; The specific surface area of limestone powder is 400m ² /Kg～450m ² /Kg; the specific surface area of limestone powder is >700m ² /Kg; the specific surface area of activated alumina is 409.03m ² /g～440.10m ² /g; the activator is sodium hydroxide The preparation method of the modified bentonite is as follows: activate the 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 340m ² /Kg～370m ² /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, and 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, barium salt is a mixture of barium chloride, barium hydroxide and barium nitrate with a mass ratio of 1.3:2.3:2.2; fly ash is secondary fly ash; the particle size of high-sulfur tailings is 10 μm to 75 μm; The specific surface area of limestone powder is 400m ² /Kg～450m ² /Kg; the specific surface area of limestone powder is >700m ² /Kg; the specific surface area of activated alumina is 409.03m ² /Kg～440.10m ² /g; the activator is sodium hydroxide The preparation method of the modified bentonite is as follows: activate the bentonite at 530°C for 2.8 hours, then mix it with calcium oxide at a mass ratio of 3.3:1.1, and grind until the specific surface area reaches 340m ² /Kg-370m ² /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 embodiment provides a high-sulfur tailings concrete, comprising 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, water 145 parts and 12 parts of water reducing agent.

Among them, the coarse aggregate is continuously graded gravel with a particle size of 5 mm to 20 mm; the fine aggregate is river sand with a fineness modulus of 2.7 to 3.0 and an apparent density of 2520 kg/m ³ to 2620 kg/m ³ ; The water agent is a 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 it 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 embodiment provides a high-sulfur tailings concrete, comprising 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, water 155 parts and 14 parts of water reducing agent.

Among them, the coarse aggregate is continuously graded gravel with a particle size of 5 mm to 20 mm; the fine aggregate is river sand with a fineness modulus of 2.7 to 3.0 and an apparent density of 2520 kg/m ³ to 2620 kg/m ³ ; The water agent is a 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 2min, let stand for 60s, then add a water reducer, and mix and stir again at a speed of 350r/min for 4min to obtain high-sulfur tailings concrete.

Example 6

This embodiment provides a high-sulfur tailings concrete, including 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, water 150 parts and 13 parts of water reducing agent.

Among them, the coarse aggregate is continuously graded gravel with a particle size of 5 mm to 20 mm; the fine aggregate is river sand with a fineness modulus of 2.7 to 3.0 and an apparent density of 2520 kg/m ³ to 2620 kg/m ³ ; The water agent is a 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 330r/min for 1.5min, let stand for 45s, then add a water reducer, and mix and stir for 3.5min at a speed of 320r/min 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 nitric acid with a mass ratio of 1.2:6:2.0 barium composition.

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 in 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 Shown:

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 the high-sulfur tailings cementitious material is added, the sulfate erosion resistance is effectively improved, the fluidity and slump retention are good, and the concrete is improved. The purpose of safety and durability, and low preparation cost, realizes the secondary utilization of solid waste, and solves the problem of low concrete strength caused by high-sulfur tailings used as cemented filling aggregate.

The above description is only a preferred embodiment of the present invention, and is 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 in the protection of the present invention. within range.

Claims (10)

1. A high-sulfur tailing cementing material is characterized in that: the material comprises the following raw material components in parts by weight: 200 to 220 parts of cement, 70 to 90 parts of fly ash, 40 to 60 parts of high-sulfur tailings, 40 to 60 parts of mineral powder, 6 to 8 parts of limestone powder, 6 to 12 parts of barium salt, 13 to 15 parts of modified bentonite, 7 to 13 parts of activated alumina and 3 to 5 parts of excitant; wherein the barium salt is prepared from the following components in a mass ratio of 1.2-1.5: 2.1-2.5: 2.0 to 2.4 of barium chloride, barium hydroxide and barium nitrate.

2. The high sulfur tailings cementitious material of claim 1, wherein: the fly ash is secondary fly ash; and/or

The grain size of the high-sulfur tailings is 10-75 mu m; and/or

The specific surface area of the mineral powder is 400m ² /Kg～450m ² /Kg。

3. The high sulfur tailings cementitious material of claim 1, wherein: the specific surface area of the limestone powder is more than 700m ² Per Kg; and/or

The specific surface area of the activated alumina is 409.03m ² /g～440.10m ² (iv) g; and/or

The excitant is sodium hydroxide.

4. The high sulfur tailings cementitious material of claim 1, wherein: the preparation method of the modified bentonite comprises the following steps: activating the bentonite at 500-550 ℃ for 2.5-3.0 h, and then mixing the bentonite with calcium oxide at a ratio of 3.2-3.3: 1 to 1.1, and grinding the mixture until the specific surface area reaches 340m ² /Kg～370m ² and/Kg, obtaining the modified bentonite.

5. The method for preparing the high-sulfur tailing cement of any one of claims 1 to 4, characterized in that: the method comprises the following steps:

(1) Mixing the modified bentonite and the bentonite according to the weight ratioMixing the hair agents, and grinding to obtain the product with specific surface area of 400m ² /Kg～450m ² Powder per Kg;

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

6. The high-sulfur tailing concrete is characterized in that: comprising the high-sulfur tailing cementitious material according to any one of claims 1 to 4.

7. The high sulfur tailings concrete of claim 6, wherein: the high-sulfur tailing concrete comprises the following raw material components in parts by weight: 400-500 parts of high-sulfur tailing cementing 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.

8. The high sulfur tailings concrete of claim 7, wherein: the coarse aggregate is continuous graded broken stone with the grain size of 5-20 mm; and/or

The fine aggregate has fineness modulus of 2.7-3.0 and apparent density of 2520kg/m ³ ～2620kg/m ³ The river sand of (1); and/or

The water reducing agent is a polycarboxylic acid water reducing agent.

9. The method for preparing high-sulfur tailing concrete according to claim 7 or 8, characterized in that: the method comprises the following steps:

(1) Uniformly mixing the coarse aggregate and the fine aggregate according to the weight ratio to obtain a prepared material;

(2) And mixing and stirring the prepared material, the high-sulfur tailing cementing material and water for the first time at the rotating speed of 300-350 r/min, standing for 30-60 s, adding the water reducing agent, and mixing and stirring for the second time at the rotating speed of 300-350 r/min to obtain the high-sulfur tailing concrete.

10. The method for preparing the high-sulfur tailing concrete according to claim 9, characterized in that: in the step (2), the first mixing and stirring time is 1-2 min, and the second mixing and stirring time is 3-4 min.