Preparation process of sulfur-containing tailings non-burned brick

Abstract

The application discloses a preparation process of sulfur-containing tailing non-burned brick, which comprises the following steps: (1) mixing ethanol and water to form a mixing liquid, then adding silicate cement powder, gypsum powder and sodium alginate powder into the mixing liquid to form a slurry; coating the slurry onto the surface of sulfur-containing tailing, and then naturally curing to obtain sulfur-containing tailing aggregate; (2) uniformly mixing fly ash, lithium slag, the sulfur-containing tailing aggregate, cement, water reducing agent and water, then performing curing after the obtained mixture is pressed into a shape, and thus the sulfur-containing tailing non-burned brick is obtained. The process can effectively improve the chemical stability of the sulfur-containing tailing, and solves the problem that the sulfur-containing tailing easily causes the mechanical property of the non-burned brick to deteriorate.

Description

Technical Field

[0001] This invention relates to the field of non-fired brick preparation technology, and in particular to a preparation process for non-fired bricks containing sulfur tailings. Background Technology

[0002] Non-fired bricks are a new type of wall material made from industrial waste (such as fly ash, coal gangue, and tailings slag) as the main raw material. They do not require high-temperature sintering but are instead mechanically pressed and then naturally cured or steam-cured. As a substitute for traditional sintered bricks, non-fired bricks have many advantages. For example, because they do not require high-temperature sintering, they have lower energy consumption and carbon emissions, making them more environmentally friendly and reducing manufacturing costs. Furthermore, non-fired bricks allow for larger-scale resource utilization of industrial waste, alleviating the waste of land resources and environmental pollution caused by the accumulation of large amounts of industrial waste. Sulfur-containing tailings are waste generated during the mining of metal ores (such as copper and gold mines). Because these metal ores often contain pyrite (mainly FeS2), the resulting tailings also contain a high content of FeS2, hence the name sulfur-containing tailings. When this waste is used directly as raw material for non-fired bricks, it easily causes cracks and a decline in mechanical properties. The main reason is that FeS2 in sulfur-containing tailings is easily oxidized when it encounters water and oxygen. The resulting sulfuric acid reacts with calcium hydroxide, a cement hydration product in the unfired bricks, to form calcium sulfate. This calcium sulfate further reacts with unhydrated calcium aluminate from the cement clinker in the unfired bricks to form expansive ettringite. When this ettringite forms in the already solidified unfired bricks, it easily generates expansion stress. When this stress exceeds the crack resistance limit of the unfired bricks, cracks will form, leading to a decrease in the mechanical properties of the unfired bricks, and in severe cases, even cracking. These characteristics of sulfur-containing tailings make them unsuitable as raw materials for unfired bricks, and are a key issue affecting the resource utilization of sulfur-containing tailings. Summary of the Invention

[0003] In view of this, the present invention provides a preparation process for sulfur-containing tailings-based non-fired bricks, which can effectively improve the chemical stability of sulfur-containing tailings and alleviate the problem that sulfur-containing tailings easily cause deterioration of the mechanical properties of non-fired bricks. Specifically, the present invention discloses the technical solution as follows.

[0004] A process for preparing sulfur-containing tailings non-fired bricks includes the following steps:

[0005] (1) Mix ethanol and water to prepare a mixing liquid, and then add silicate cement powder, gypsum powder and sodium alginate powder to form a slurry. Coat the surface of the sulfur-containing tailings with the slurry, and then cure it naturally. After completion, sulfur-containing tailings aggregate is obtained for later use.

[0006] (2) Mix fly ash, lithium slag, sulfur-containing tailings aggregate, cement, water-reducing agent and water evenly, then press the resulting mixture into shape and cure it to obtain sulfur-containing tailings non-fired bricks.

[0007] Furthermore, in step (1), the mass fraction of ethanol in the mixing liquid is 60-70%. Its presence of a certain amount of water allows for partial hydration of the cement in the slurry coating the sulfur-containing tailings, causing the slurry to adhere to the sulfur-containing tailings.

[0008] Further, in step (1), the ratio of the mixing liquid, silicate cement powder, gypsum powder, and sodium alginate powder is 5ml: 0.4~0.55g: 0.06~0.08g, 0.1~0.15g.

[0009] Further, in step (1), the ratio of the slurry to the sulfur-containing tailings is 30-35 parts by weight: 92-100 parts by weight. Optionally, the particle size of the sulfur-containing tailings is 5-10 mm.

[0010] Furthermore, in step (1), the curing time is 2 to 5 days. Through curing, the slurry coating the sulfur-containing tailings hardens and bonds to the tailings, forming an active coating layer. This active coating layer can continue to undergo hydration reaction during the subsequent preparation of non-fired bricks, thereby improving the bonding force between the sulfur-containing tailings aggregate and the non-fired brick matrix and enhancing the strength of the non-fired bricks.

[0011] Further, in step (2), the weight ratios of fly ash, lithium slag, sulfur-containing tailings aggregate, cement, water-reducing agent, and water are 25-35 parts: 20-30 parts: 45-60 parts: 10-16 parts: 1.8-2.4 parts: 20-27 parts, respectively. Replacing part of the fly ash with lithium slag helps improve the mechanical strength of the non-fired bricks.

[0012] Optionally, in step (2), the water-reducing agent includes any one of polycarboxylate water-reducing agents, aminosulfonate water-reducing agents, naphthalene-based water-reducing agents, etc. Optionally, the water-reducing agent has a water reduction rate of 20-30%.

[0013] Further, in step (2), the mixture further includes 5-8 parts by weight of repair agent and 0.7-1.2 parts by weight of curing agent. The preparation methods of the repair agent and curing agent include the following steps: (i) mixing ethylene acetate-ethylene copolymer powder with anhydrous ethanol to prepare a coating solution. (ii) mixing corn cob particles with a saturated aqueous solution of sodium methylsiloxane and allowing it to stand until the corn cob particles are saturated with adsorption, then removing and drying them. After completion, coating the surface of the corn cob particles with the coating solution, and then heating and curing to obtain the repair agent. (iii) applying the coating solution to the surface of diphenylmethane diisocyanate (MDI) particles for coating, and then heating and curing to obtain the curing agent.

[0014] Further, in step (ii), the solid content of the coating liquid is between 40% and 45%. Optionally, the particle size of the corn cob particles is 1-2 mm. Using the corn cob as a carrier not only has a good function of absorbing and storing sodium methylsilanolate, but also allows it to be easily torn when encountering tensile stress in cracks, thus exposing the sodium methylsilanolate in time, and releasing it into the cracks for crack repair when it encounters moisture.

[0015] Further, in step (ii), the temperature of the heat curing treatment is 50–65°C, and the time is 20–30 min. Heat curing causes the ethanol in the coating liquid on the surface of the corn cob particles to evaporate rapidly, thereby forming a polymer coating layer. This prevents the release of sodium methylsilanol salt from the corn cob during the preparation of the non-fired bricks, which would affect the repair ability of the repair agent.

[0016] Further, in step (iii), the particle size of the diphenylmethane diisocyanate is 20-40 mesh. Optionally, in step (iii), the solid content of the coating liquid is between 40-45%. The coating liquid encapsulates the MDI, preventing it from reacting with water during the preparation of the unfired bricks, thus preventing premature failure of the curing agent and affecting the repair ability of cracks in the unfired bricks later.

[0017] Further, in step (iii), the temperature of the heat curing treatment is 50-65°C and the time is 15-25 min.

[0018] Further, step (2) also includes 2 to 4 parts by weight of fiber filaments. Optionally, the fiber filaments include at least one of polypropylene fiber, polyacrylonitrile fiber, carbon fiber, etc. Optionally, the length of the fiber filaments is 10 to 35 mm. The fiber filaments help improve the crack resistance of the unfired bricks.

[0019] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0020] When pyrite, a byproduct of sulfur-containing tailings, is used directly as raw material for non-fired bricks, it easily leads to deterioration of the mechanical strength of the bricks. Therefore, this invention pre-treats the sulfur-containing tailings, forming a coating layer on their surface. After the sulfur-containing tailings are used as raw material to make non-fired bricks, the coating layer can prevent the oxidation of FeS2 in the tailings to produce sulfate ions, thereby preventing cracks in the non-fired bricks and the resulting deterioration of mechanical properties. Firstly, this invention uses a mixing liquid containing a certain amount of water to form a slurry with silicate cement, gypsum, sodium alginate, and sodium methylsiloxane. This slurry is then coated onto the surface of the sulfur-containing tailings and cured. During this process, the cement undergoes partial pre-hydration using a small amount of water provided by the mixing liquid. On one hand, the cementitious products formed by pre-hydration can bond the coating layer with the sulfur-containing tailings. On the other hand, the pre-hydrated coating layer still retains some unhydrated cement clinker. When preparing non-fired bricks using the aforementioned sulfur-containing tailings, during the curing process, the unhydrated cement clinker in the coating layer undergoes a hydration reaction simultaneously with the cement components in the non-fired brick under the action of water. Both form cementitious components, which are intermixed, effectively improving the bonding force between the sulfur-containing tailings aggregate and the non-fired brick matrix. At this time, the coating layer transforms into an interfacial transition layer, thereby improving the mechanical strength of the non-fired brick. Simultaneously, the unhydrated cement clinker in the coating layer provides a large amount of calcium ions during the continued hydration process. The sodium alginate in the coating layer dissolves in the water entering the coating layer and further forms an organic film under the cross-linking effect of these calcium ions, sealing the coating layer. This prevents the sulfur-containing tailings from generating sulfate ions upon contact with oxygen and water during the service life of the non-fired brick, which would then transform into expansive ettringite. Since the non-fired brick has already undergone long-term curing and solidification, the formation of these ettringite ions can easily cause expansion stress, leading to internal cracks in the non-fired brick and a decrease in mechanical strength. Furthermore, the non-fired bricks of this invention incorporate a repair agent and a curing agent. When cracks develop during the later stages of the non-fired brick's service life, the repair agent and curing agent at the crack interface are torn apart. The sodium methylsiloxane salt within these components dissolves and is released into the crack under the influence of incoming moisture. The MDI reacts with water to form carbon dioxide, which in turn causes the sodium methylsiloxane salt to form a waterproof silicone resin film under the action of water and carbon dioxide, sealing and repairing the crack. This invention utilizes the repair agent and curing agent to activate a repair mechanism when cracks occur, helping to improve the isolation ability against sulfur-containing tailings and extending the service life of the non-fired bricks. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 The following is a sample image of sulfur-containing tailings in the examples below.

[0023] Figure 2 The following are XRD patterns of sulfur-containing tailings in the examples.

[0024] Figure 3 The image shows a brick blank sample prepared in Example 1 below. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the methods of the present invention. The preferred embodiments and materials described in this invention are for illustrative purposes only. The technical solutions of the present invention will now be further described in detail with reference to the accompanying drawings and specific embodiments.

[0026] In the following embodiments, the sulfur-containing tailings are from a mining area in Tongling City, Anhui Province (e.g., Figure 1 Its XRD test pattern is as follows: Figure 2 As shown in the figure, its FeS2 content is 8.44%. After crushing and screening, sulfur-containing tailings with a continuous gradation of particle size between 5 and 10 mm are obtained.

[0027] Example 1

[0028] A process for preparing sulfur-containing tailings non-fired bricks includes the following steps:

[0029] (1) Prepare a mixing solution with ethanol and water at a mass fraction of 60%. Then, add the above-mentioned raw materials to each 5 ml of the mixing solution at a ratio of 0.5 g of ordinary silicate cement powder, 0.07 g of gypsum powder, and 0.13 g of sodium alginate powder. Stir for 2 minutes to form a slurry. Mix the slurry with sulfur-containing tailings at a ratio of 35 parts by weight: 95 parts by weight and coat the tailings with the mixture under stirring. Then, separate the coated sulfur-containing tailings with a sieve and cure them at 25±2℃ for 3 days. After completion, sulfur-containing tailings aggregate is obtained for later use.

[0030] (2) Fly ash, lithium slag, the sulfur-containing tailings aggregate prepared in this embodiment, 42.5 ordinary silicate cement, polycarboxylate superplasticizer (water reduction rate 30%), and water are placed in a mixer in a ratio of 30 parts by weight: 25 parts by weight: 50 parts by weight: 14 parts by weight: 2.0 parts by weight: 25 parts by weight and mixed for 3 minutes. The resulting mixture is then poured into a mold and pressed into shape (pressure 130KN, time 3 minutes). The resulting brick blank (e.g.) Figure 3(As shown) The bricks were naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings-free bricks were obtained. The compressive strength of the sulfur-containing tailings-free bricks prepared in this embodiment was tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 37.29 MPa.

[0031] Example 2

[0032] A process for preparing sulfur-containing tailings non-fired bricks includes the following steps:

[0033] (1) Prepare a mixing solution with ethanol and water at a mass fraction of 65%. Then, add the above-mentioned raw materials to each 5 ml of the mixing solution at a ratio of 0.55 g of ordinary silicate cement powder, 0.08 g of gypsum powder, and 0.15 g of sodium alginate powder. Stir for 2 minutes to form a slurry. Mix the slurry with sulfur-containing tailings at a ratio of 30 parts by weight to 92 parts by weight and coat it with the mixture under stirring. Then, separate the coated sulfur-containing tailings with a sieve and cure it at 25±2℃ for 2 days. After completion, sulfur-containing tailings aggregate is obtained for later use.

[0034] (2) Fly ash, lithium slag, the sulfur-containing tailings aggregate prepared in this embodiment, 42.5 ordinary Portland cement, polycarboxylate superplasticizer (water reduction rate 20%), and water were placed in a mixer in a ratio of 35 parts by weight: 30 parts by weight: 60 parts by weight: 16 parts by weight: 2.4 parts by weight: 27 parts by weight and mixed for 3 minutes. The resulting mixture was then poured into a mold and pressed into shape (pressure 110KN, time 5 minutes). The resulting brick blanks were then naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings non-fired bricks were obtained. The compressive strength of the sulfur-containing tailings non-fired bricks prepared in this embodiment was tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 39.61 MPa.

[0035] Example 3

[0036] A process for preparing sulfur-containing tailings non-fired bricks includes the following steps:

[0037] (1) Prepare a mixing solution with 70% ethanol by mass by mixing ethanol and water. Then, add the above-mentioned raw materials to each 5 ml of the mixing solution at a ratio of 0.4 g of ordinary silicate cement powder, 0.06 g of gypsum powder, and 0.1 g of sodium alginate powder. Stir for 2 minutes to form a slurry. Mix the slurry with sulfur-containing tailings at a ratio of 35 parts by weight: 100 parts by weight and coat the tailings with the mixture under stirring. Then, separate the coated sulfur-containing tailings with a sieve and cure them at 25±2℃ for 5 days. After completion, sulfur-containing tailings aggregate is obtained for later use.

[0038] (2) Preparation of repair agent and curing agent: (i) Ethylene acetate-ethylene copolymer powder is mixed with anhydrous ethanol to prepare a coating liquid with a solid content of 45%. (ii) Corn cob particles with a particle size distribution between 1 and 2 mm are mixed with a saturated aqueous solution of sodium methylsiloxane and stirred for 5 min, then allowed to stand for 5 min. The corn cob particles are then filtered out and dried at 60°C for 2 hours. After drying, the corn cob particles are immersed in the coating liquid to form a slurry, and then the slurry-coated corn cob particles are filtered out and kept at 65°C for 20 min to allow the coating liquid on the corn cob particles to solidify into a film, thus obtaining the repair agent. (iii) MDI particles with a particle size distribution between 20 and 40 mesh are immersed in the coating liquid to form a slurry, and then the slurry-coated MDI particles are filtered out and dispersed by vibration, and then kept at 65°C for 15 min to obtain the curing agent.

[0039] (3) Fly ash, lithium slag, the sulfur-containing tailings aggregate prepared in this embodiment, 42.5 ordinary silicate cement, naphthalene-based water-reducing agent (water reduction rate 25%), the repair agent prepared in this embodiment, the curing agent prepared in this embodiment, 10mm long polypropylene fiber, and water were placed in a mixer in the following proportions: 32 parts by weight: 27 parts by weight: 55 parts by weight: 14 parts by weight: 2.1 parts by weight: 8 parts by weight, 1.2 parts by weight, 4 parts by weight, and 25 parts by weight, respectively, and mixed for 3 minutes. The resulting mixture was then poured into a mold and pressed into shape (pressure 120KN, time 4 minutes). The resulting brick blanks were then naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings non-fired bricks were obtained. The compressive strength of the sulfur-containing tailings non-fired bricks prepared in this embodiment was tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 42.04MPa.

[0040] Example 4

[0041] A process for preparing sulfur-containing tailings non-fired bricks includes the following steps:

[0042] (1) Prepare a mixing solution with ethanol and water at a mass fraction of 60%. Then, add the above-mentioned raw materials to each 5 ml of the mixing solution at a ratio of 0.45 g of ordinary silicate cement powder, 0.07 g of gypsum powder, and 0.15 g of sodium alginate powder. Stir for 2 minutes to form a slurry. Mix the slurry with sulfur-containing tailings at a ratio of 32 parts by weight: 96 parts by weight and coat it with the mixture under stirring. Then, separate the coated sulfur-containing tailings with a sieve and cure it at 25±2℃ for 4 days. After completion, sulfur-containing tailings aggregate is obtained for later use.

[0043] (2) Preparation of repair agent and curing agent: (i) Mix ethylene acetate-ethylene copolymer powder with anhydrous ethanol to prepare a coating liquid with a solid content of 40%. (ii) Mix corn cob particles with a particle size distribution between 1 and 2 mm with a saturated aqueous solution of sodium methylsiloxane, stir for 5 min, and then let stand for 5 min. Then filter out the corn cob particles and dry them at 60°C for 2 hours. After completion, immerse the obtained corn cob particles in the coating liquid to coat them, then filter out the coated corn cob particles and keep them at 50°C for 30 min to solidify the coating liquid on the corn cob particles into a film, thus obtaining the repair agent. (iii) Immerse MDI particles with a particle size distribution between 20 and 40 mesh in the coating liquid to coat them, then filter out the coated MDI particles and disperse them by vibration, then keep them at 50°C for 25 min to obtain the curing agent.

[0044] (3) Fly ash, lithium slag, the sulfur-containing tailings aggregate prepared in this embodiment, 42.5 ordinary silicate cement, polycarboxylate superplasticizer (water reduction rate 20%), the repair agent prepared in this embodiment, the curing agent prepared in this embodiment, carbon fibers with a length of 35 mm, and water were placed in a mixer in the following proportions: 25 parts by weight: 20 parts by weight: 45 parts by weight: 10 parts by weight: 1.8 parts by weight: 5 parts by weight, 0.7 parts by weight, 2 parts by weight, and 20 parts by weight, and mixed for 3 minutes. The resulting mixture was then poured into a mold and pressed into shape (pressure 140 KN, time 2 minutes). The resulting brick blank was then naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings non-fired bricks were obtained. The compressive strength of the sulfur-containing tailings non-fired bricks prepared in this embodiment was tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 41.32 MPa.

[0045] Example 5

[0046] A process for preparing sulfur-containing tailings-free bricks includes the following steps: fly ash, lithium slag, sulfur-containing tailings not treated in step (1) of Example 1, 42.5 ordinary silicate cement, polycarboxylate superplasticizer (water reduction rate 30%), and water are placed in a mixer in a ratio of 30 parts by weight: 25 parts by weight: 50 parts by weight: 14 parts by weight: 2.0 parts by weight: 25 parts by weight and mixed for 3 minutes. The resulting mixture is then poured into a mold and pressed (pressure 130KN, time 3 minutes). The resulting brick blanks are then naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings-free bricks are obtained. The compressive strength of the sulfur-containing tailings-free bricks prepared in this embodiment was tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 13.17MPa.

[0047] Example 6

[0048] A preparation process for sulfur-containing tailings-free bricks differs from Example 1 above in that the sulfur-containing tailings aggregate in this example is prepared as follows: Ethanol and water are mixed to prepare a mixing liquid with an ethanol mass fraction of 60%. Then, 0.5g of 42.5% ordinary silicate cement powder and 0.07g of gypsum powder are added to each 5ml of the mixing liquid, and the mixture is stirred for 2 minutes to form a slurry. This slurry is mixed with sulfur-containing tailings at a ratio of 35 parts by weight: 95 parts by weight, and then coated under stirring. The coated sulfur-containing tailings are then separated using a sieve and cured at 25±2℃ for 3 days to obtain sulfur-containing tailings aggregate. The compressive strength of the sulfur-containing tailings-free bricks prepared in this example is tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result is 21.42MPa.

[0049] Example 7

[0050] A preparation process for sulfur-containing tailings-free bricks differs from that of Example 2 above in that the sulfur-containing tailings aggregate in this example is prepared as follows: 0.55g of 42.5% ordinary silicate cement powder, 0.08g of gypsum powder, and 0.15g of sodium alginate powder are added to 5ml of clean water, and then stirred for 2 minutes to form a slurry. This slurry is mixed with sulfur-containing tailings at a ratio of 30 parts by weight: 92 parts by weight, and then coated under stirring. The coated sulfur-containing tailings are then separated using a sieve and cured at 25±2℃ for 2 days to obtain sulfur-containing tailings aggregate. The compressive strength of the sulfur-containing tailings-free bricks prepared in this example is tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result is 32.75MPa.

[0051] Example 8

[0052] A preparation process for sulfur-containing tailings-free bricks differs from that of Example 3 above in that: fly ash, lithium slag, sulfur-containing tailings aggregate prepared in Example 3, 42.5 ordinary silicate cement, naphthalene-based water-reducing agent (water reduction rate 25%), the repair agent prepared in Example 3, 10mm long polypropylene fibers, and water are placed in a mixer in the following proportions: 32 parts by weight: 27 parts by weight: 55 parts by weight: 14 parts by weight: 2.1 parts by weight: 8 parts by weight, 4 parts by weight, and 25 parts by weight, and mixed for 3 minutes. The resulting mixture is then poured into a mold and pressed (pressure 120KN, time 4 minutes). The resulting brick blanks are then naturally cured at 25±2℃ for three weeks, with watering once a day for the first week. After completion, sulfur-containing tailings-free bricks are obtained.

[0053] The obtained sulfur-containing tailings unfired bricks were placed on a press and pre-compressed with a load of 900 N to create cracks inside the bricks. The bricks were then placed in a curing chamber with a relative humidity of 95% and a temperature of 21±2℃ for 24 hours. The compressive strength of the obtained sulfur-containing tailings unfired bricks was then tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 24.11 MPa. The unfired bricks prepared in Example 3 were pre-compressed using the same method and then kept in the same curing chamber for 24 hours. The compressive strength of these unfired bricks was then tested, and the result was 38.51 MPa.

[0054] Example 9

[0055] The preparation process of a sulfur-containing tailings non-fired brick differs from that of Example 3 above in that the repair agent in this example is prepared by the following method: corn cob particles with a particle size distribution between 1 and 2 mm are mixed with a saturated aqueous solution of sodium methylsiloxane, stirred for 5 minutes, and then allowed to stand for 5 minutes. The corn cob particles are then filtered out and dried at 60°C for 2 hours to obtain the repair agent.

[0056] The obtained sulfur-containing tailings unfired bricks were pre-compressed on a press with a load of 900N to create cracks inside the bricks. The bricks were then placed in a curing chamber at 95% relative humidity and 21±2℃ for 24 hours. The compressive strength of the obtained sulfur-containing tailings unfired bricks was then tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 18.26 MPa. The unfired bricks prepared in Example 3 were pre-compressed using the same method and then kept in the same curing chamber for 24 hours. The compressive strength of these unfired bricks was then tested, and the result was 36.72 MPa.

[0057] Example 10

[0058] A preparation process for sulfur-containing tailings non-fired bricks differs from that of Example 4 above in that the repair agent in this example is prepared using the following method: (i) Ethylene acetate-ethylene copolymer powder is mixed with anhydrous ethanol to prepare a coating liquid with a solid content of 40%. (ii) Zeolite particles with a particle size distribution between 1 and 2 mm are mixed with a saturated aqueous solution of sodium methylsiloxane and stirred for 5 minutes, then allowed to stand for 5 minutes. The zeolite particles are then filtered out and dried at 60°C for 2 hours. After completion, the obtained zeolite particles are immersed in the coating liquid to form a slurry, and then the slurry-coated zeolite particles are filtered out and kept at 50°C for 30 minutes to allow the coating liquid on the zeolite particles to solidify into a film, thus obtaining the repair agent.

[0059] The obtained sulfur-containing tailings unfired bricks were pre-compressed on a press with a load of 900N to create cracks inside the bricks. The bricks were then placed in a curing chamber at 95% relative humidity and 21±2℃ for 24 hours. The compressive strength of the obtained sulfur-containing tailings unfired bricks was then tested according to the "Test Methods for Masonry Bricks" (GB / T 2542-2012), and the result was 15.49 MPa. The unfired bricks prepared in Example 4 were pre-compressed using the same method and then kept in the same curing chamber for 24 hours. The compressive strength of these unfired bricks was then tested, and the result was 39.08 MPa.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for preparing sulfur-containing tailings-free bricks, characterized in that, Includes the following steps: (1) Mix ethanol and water to prepare a mixing liquid, and then add silicate cement powder, gypsum powder and sodium alginate powder to form a slurry; the ratio of the mixing liquid, silicate cement powder, gypsum powder and sodium alginate powder is 5ml: 0.4~0.55g: 0.06~0.08g, 0.1~0.15g; coat the slurry onto the surface of sulfur-containing tailings, and then cure it naturally. After completion, sulfur-containing tailings aggregate is obtained for later use. (2) Fly ash, lithium slag, the sulfur-containing tailings aggregate, cement, water-reducing agent, and water are mixed evenly in a weight ratio of 25-35 parts: 20-30 parts: 45-60 parts: 10-16 parts: 1.8-2.4 parts: 20-27 parts. The resulting mixture is then pressed into shape and cured to obtain sulfur-containing tailings non-fired bricks. The mixture also includes 5-8 parts by weight of repair agent and 0.7-1.2 parts by weight of curing agent. The preparation method includes the following steps: (i) Prepare a coating solution by mixing ethylene acetate-ethylene copolymer powder with anhydrous ethanol; (ii) Mix corn cob particles with a saturated aqueous solution of sodium methylsiloxane and let stand until the corn cob particles are saturated with adsorption. Then remove and dry them. After completion, coat the surface of the corn cob particles with the coating liquid and then heat to cure them to obtain the repair agent. (iii) The coating liquid is applied to the surface of the diphenylmethane diisocyanate particles for coating, and then heated and cured to obtain the curing agent.

2. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (1), the mass fraction of ethanol in the mixing liquid is 60-70%.

3. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (1), the ratio of the slurry to the sulfur-containing tailings is 30-35 parts by weight: 92-100 parts by weight.

4. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (1), the particle size of the sulfur-containing tailings is 5~10mm.

5. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (1), the maintenance time is 2 to 5 days.

6. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (ii), the solid content of the coating liquid is between 40% and 45%.

7. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (ii), the temperature of the heating and curing treatment is 50~65℃ and the time is 20~30min.

8. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (iii), the particle size of the diphenylmethane diisocyanate is 20-40 mesh.

9. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (iii), the solid content of the coating liquid is between 40% and 45%.

10. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, In step (iii), the temperature of the heat curing treatment is 50~65℃ and the time is 15~25min.

11. The preparation process of sulfur-containing tailings non-fired bricks according to any one of claims 1-10, characterized in that, Step (2) also includes 2 to 4 parts by weight of fiber filaments.

12. The preparation process of sulfur-containing tailings non-fired bricks according to claim 11, characterized in that, The fiber filaments include at least one of polypropylene fiber, polyacrylonitrile fiber, and carbon fiber.

13. The preparation process of sulfur-containing tailings non-fired bricks according to claim 12, characterized in that, The length of the fiber is 10~35mm.

14. The preparation process of sulfur-containing tailings non-fired bricks according to any one of claims 1-7, characterized in that, In step (2), the water-reducing agent includes any one of polycarboxylate water-reducing agent, aminosulfonate water-reducing agent, and naphthalene-based water-reducing agent.

15. The preparation process of sulfur-containing tailings non-fired bricks according to claim 1, characterized in that, The water-reducing agent has a water reduction rate of 20-30%.

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