Modified manganese slag and application thereof in preparation of cement material

Abstract

The invention belongs to the technical field of solid waste treatment and utilization, and particularly relates to modified manganese slag and application thereof in preparation of a cement material. The modified manganese slag disclosed by the invention is prepared by a method comprising the following steps: uniformly mixing maleic anhydride grafted polyethylene, epoxy group modified manganese slag, epoxy group modified nano alumina fiber and epoxy group modified basalt fiber, and then performing melt extrusion to obtain a polyethylene grafted manganese slag-polybasic fiber compound, and uniformly mixing the polyethylene grafted manganese slag-polybasic fiber compound and 5-chlorosulfonyl-2-hydroxybenzoic acid, and carrying out melt extrusion to obtain the modified manganese slag. The basalt fiber and the nano alumina fiber are combined with the manganese slag through chemical bonds and polyethylene long chains to form a compound, so that the combination stability and dispersion uniformity of the basalt fiber, the alumina fiber and the manganese slag can be improved, and the basalt fiber and the alumina fiber can play an anchoring role in a cement material; the mechanical strength and the low-temperature freezing resistance of the cement material are improved.

Description

A modified manganese slag and its application in the preparation of cement materials Technical Field

[0001] This invention belongs to the field of solid waste treatment and utilization technology, specifically a modified manganese slag and its application in the preparation of cement materials. Background Technology

[0002] Electrolytic manganese slag is the acid leaching residue produced during the electrolytic production of metallic manganese from rhodochrosite or pyrolusite, and is a major solid waste of the electrolytic manganese industry. Statistics show that when approximately 12% of rhodochrosite is directly leached to produce electrolytic manganese, 1 ton of metallic manganese produces 8-12 tons of electrolytic manganese slag; when pyrolusite is used to produce electrolytic manganese, 1 ton of metallic manganese produces 3-5 tons of electrolytic manganese slag. Currently, the disposal of electrolytic manganese slag is mainly through open-air stockpiling, with a comprehensive utilization rate of less than 10%. Currently, the comprehensive resource utilization of electrolytic manganese slag mainly includes: recovery of valuable resources such as manganese, magnesium, ammonium, iron, and silicon; preparation of microcrystalline glass, ceramics, and ceramsite materials; preparation of cement-based materials, cement clinker, geopolymers, roadbeds, non-fired bricks, and sintered bricks; preparation of modified electrolytic manganese slag, manganese-based composite materials, and manganese-based catalysts for ecological restoration; preparation of cement-based materials for mine backfilling and other fields.

[0003] Electrolytic manganese slag is used to prepare cement-based materials, which is an important way to realize its resource utilization, reduce the production cost of cement-based materials, and reduce carbon dioxide emissions. However, when manganese slag is added to cement materials, it will lead to a decrease in the compressive strength of the cement materials, affecting their normal use. Summary of the Invention

[0004] To address the above problems, this invention provides a modified manganese slag and its application in the preparation of cement materials, which solves the problem that adding manganese slag to cement materials leads to a decrease in the compressive strength of the cement materials.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A modified manganese slag is prepared by a method comprising the following steps: maleic anhydride-grafted polyethylene, epoxy-modified manganese slag, epoxy-modified nano-alumina fibers, and epoxy-modified basalt fibers are mixed and melt-extruded to obtain a polyethylene-grafted manganese slag-multi-component fiber composite; the polyethylene-grafted manganese slag-multi-component fiber composite is then mixed with 5-chlorosulfonyl-2-hydroxybenzoic acid and melt-extruded to obtain the modified manganese slag; the mass ratio of the epoxy-modified manganese slag, epoxy-modified nano-alumina fibers, and epoxy-modified basalt fibers is 1:0.1~0.2:0.3~0.5; the molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is equal to the sum of the molar amounts of epoxy groups in the epoxy-modified manganese slag, epoxy-modified nano-alumina fibers, and epoxy-modified basalt fibers; the molar ratio of the molar amount of 5-chlorosulfonyl-2-hydroxybenzoic acid to the molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is 1:1.

[0007] Preferably, the preparation method of the epoxy-modified manganese slag is as follows: manganese slag and γ-(2,3-epoxypropoxy)propyltrimethoxysilane are mixed and reacted in a solvent at 100~105℃ for 12~15h to obtain epoxy-modified manganese slag; the mass ratio of manganese slag to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:0.5~0.8.

[0008] Preferably, the average particle size of the manganese slag is 10~20μm.

[0009] Preferably, the chemical composition of the manganese slag is as follows: SiO2 31.5wt%, CaO 37.1wt%, F2O3 3.9wt%, Al2O3 10.2wt%, MgO 4.1wt%, SO3 5.8wt%, MnO 3.3wt%, and loss on ignition 4.1wt%.

[0010] Preferably, the preparation method of the epoxy-modified nano-alumina fiber is as follows: An epoxy silane coupling agent, ethanol, and water are mixed in a mass ratio of 2~3:70~80:8~12, and the pH is adjusted to 4~5 with acetic acid. The mixture is stirred for 30~45 min, then nano-alumina fibers are added, and the mixture is heated to 65~70℃ and reacted for 10~12 h to obtain epoxy-modified nano-alumina fibers. The mass ratio of nano-alumina fibers to epoxy silane coupling agent is 1:0.9~1.1, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0011] Preferably, the nano-alumina fibers have an average diameter of 5-10 nm and an average length of 8-15 nm.

[0012] Preferably, the preparation method of the epoxy-modified basalt fiber is as follows: an epoxy silane coupling agent, ethanol and water are mixed in a mass ratio of 2~3:70~80:8~12, the pH is adjusted to 4~5 with acetic acid, and the mixture is mixed for 30~45 min. Then, basalt fiber is added, heated to 65~70℃, and the mixture is reacted for 7~9 h to obtain epoxy-modified basalt fiber; the mass ratio of basalt fiber to epoxy silane coupling agent is 1:0.7~0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0013] Preferably, the basalt fibers have an average diameter of 5-10 μm and an average length of 0.2-0.6 mm.

[0014] Preferably, the maleic anhydride-grafted polyethylene has a grafting rate of 1.2-1.5%, a melt index of 0.8-1.0 g / 10 min tested at a temperature of 190°C and a load of 2.16 kg, a melt extrusion temperature of 200-220°C, and an average particle size of 1.8-2.5 mm for the modified manganese slag.

[0015] Application of a modified manganese slag as described above in the preparation of cement materials.

[0016] The beneficial effects of the modified manganese slag of this invention and its application in the preparation of cement materials are as follows: In this invention, basalt fibers and nano-alumina fibers are combined with manganese slag through chemical bonds and polyethylene long chains to form a composite, which can improve the bonding stability and dispersion uniformity of basalt fibers, nano-alumina fibers and manganese slag. Basalt fibers and nano-alumina fibers can play an anchoring role in cement materials, improving the flexural strength and low-temperature freeze-thaw resistance of cement materials; when larger basalt fibers and smaller nano-alumina fibers are used together, the anchoring effect is stronger, and fibers of different sizes can prevent cracks of different sizes. The expansion of the texture further improves the flexural strength of cement materials. When basalt fiber and nano-alumina fiber are used in combination, the compressive strength of cement materials can be effectively improved. Furthermore, this invention utilizes a chemical reaction between 5-chlorosulfonyl-2-hydroxybenzoic acid and the hydroxyl groups in the manganese slag-fiber composite grafted with polyethylene. This allows carboxyl and phenolic hydroxyl groups to be grafted onto the surface of the modified manganese slag, thereby improving the dispersibility of the modified manganese slag and enhancing the contact area between the modified manganese slag and the components in the cement slurry. Moreover, the modified manganese slag can bind with the components in the cement slurry through hydrogen bonds and other interactions via carboxyl and phenolic hydroxyl groups, improving the strength and freeze-thaw resistance of the cement material. In addition, with improved dispersibility, low thermal conductivity materials (e.g., basalt fiber) are more evenly dispersed, more effectively blocking the formation of heat pathways and thus reducing the thermal conductivity of the cement material. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below with reference to embodiments. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0018] The chemical composition of the manganese slag used in the following examples and comparative examples is as follows: SiO2 31.5wt%, CaO 37.1wt%, F2O3 3.9wt%, Al2O3 10.2wt%, MgO 4.1wt%, SO3 5.8wt%, MnO 3.3wt%, and loss on ignition 4.1wt%.

[0019] I. Specific embodiments of the modified manganese slag of the present invention are as follows:

[0020] Example 1

[0021] The modified manganese slag in this embodiment is prepared by a method including the following steps:

[0022] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 100°C, stir and react for 15 h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.5:60, the average particle size of manganese slag is 10 μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0023] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2:70:8 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 4, stir for 30 min, then add basalt fiber (average diameter of 5 μm and average length of 0.2 mm) to the reactor, heat to 65 °C, stir for 7 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified basalt fiber; wherein, the mass ratio of basalt fiber and epoxy silane coupling agent is 1:0.7, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0024] (3) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 3:80:12 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 5, stir for 45 min, then add nano alumina fibers (average diameter of 5 nm and average length of 8 nm) to the reactor, heat to 65 °C, stir for 10 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified nano alumina fibers; wherein, the mass ratio of nano alumina fibers to epoxy silane coupling agent is 1:0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0025] (4) Maleic anhydride-grafted polyethylene (the grafting rate of maleic anhydride-grafted polyethylene is 1.2%, and the melt index tested at a temperature of 190℃ and a load of 2.16kg is 0.8~1.0g / 10min), epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber are stirred evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 200℃ to obtain polyethylene-grafted manganese slag-multi-component fiber composite. The polyethylene-grafted manganese slag-multi-component fiber composite and 5-chlorosulfonyl-2-hydroxybenzoic acid are then mixed evenly and added to a twin-screw extruder. In the machine, modified manganese slag is melt-extruded and granulated at 200℃ to obtain modified manganese slag with an average particle size of 1.8 mm. The mass ratio of epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber is 1:0.1:0.5. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene is equal to the sum of the molar amounts of epoxy groups in epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber. The molar ratio of 5-chlorosulfonyl-2-hydroxybenzoic acid to maleic anhydride in maleic anhydride-grafted polyethylene is 1:1.

[0026] Example 2

[0027] The modified manganese slag in this embodiment is prepared by a method including the following steps:

[0028] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 102℃, stir and react for 13h, filter, wash filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.7:62, the average particle size of manganese slag is 15μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0029] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2.5:75:9 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 5, stir for 40 min, then add basalt fiber (average diameter of 8 μm and average length of 0.4 mm) to the reactor, heat to 68 °C, stir for 8 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified basalt fiber; wherein, the mass ratio of basalt fiber and epoxy silane coupling agent is 1:0.8, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0030] (3) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2.5:75:10 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 4, stir for 35 min, then add nano alumina fibers (average diameter of 8 nm and average length of 12 nm) to the reactor, heat to 68 °C, stir for 11 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified nano alumina fibers; wherein, the mass ratio of nano alumina fibers and epoxy silane coupling agent is 1:1, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0031] (4) Maleic anhydride-grafted polyethylene (with a grafting rate of 1.2%, and a melt index of 0.8~1.0 g / 10 min tested at 190℃ and a load of 2.16 kg), epoxy-modified manganese slag, epoxy-modified nano-alumina fiber, and epoxy-modified basalt fiber were mixed evenly and then added to a twin-screw extruder. The mixture was melt-extruded and granulated at 210℃ to obtain a polyethylene-grafted manganese slag-multi-component fiber composite. The polyethylene-grafted manganese slag-multi-component fiber composite and 5-chlorosulfonyl-2-hydroxybenzoic acid were then mixed evenly and added to a twin-screw extruder. During the extrusion process, the modified manganese slag is melt-extruded and granulated at 210℃ to obtain modified manganese slag with an average particle size of 2mm. The mass ratio of epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber is 1:0.2:0.3. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene is equal to the sum of the molar amounts of epoxy groups in epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber. The molar ratio of 5-chlorosulfonyl-2-hydroxybenzoic acid to maleic anhydride in maleic anhydride-grafted polyethylene is 1:1.

[0032] Example 3

[0033] The modified manganese slag in this embodiment is prepared by a method including the following steps:

[0034] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 105℃, stir and react for 12h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.8:65, the average particle size of manganese slag is 20μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0035] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 3:80:12 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 5, stir for 45 min, then add basalt fiber (average diameter of 10 μm and average length of 0.6 mm) to the reactor, heat to 70 °C, stir for 9 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified basalt fiber; wherein, the mass ratio of basalt fiber and epoxy silane coupling agent is 1:0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0036] (3) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2:70:8 to the reaction vessel, then add acetic acid to adjust the pH of the material in the reaction vessel to 4, stir for 30 min, then add nano alumina fibers (average diameter of 10 nm and average length of 15 nm) to the reaction vessel, heat to 70 °C, stir for 12 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified nano alumina fibers; wherein, the mass ratio of nano alumina fibers and epoxy silane coupling agent is 1:1.1, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0037] (4) Maleic anhydride-grafted polyethylene (the grafting rate of maleic anhydride-grafted polyethylene is 1.2%, and the melt index tested at a temperature of 190℃ and a load of 2.16kg is 0.8~1.0g / 10min), epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber are stirred evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 220℃ to obtain polyethylene-grafted manganese slag-multi-component fiber composite. The polyethylene-grafted manganese slag-multi-component fiber composite and 5-chlorosulfonyl-2-hydroxybenzoic acid are then mixed evenly and added to a twin-screw extruder. In the process, modified manganese slag was melt-extruded and granulated at 220℃ to obtain modified manganese slag with an average particle size of 2.5 mm. The mass ratio of epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber was 1:0.15:0.4. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene was equal to the sum of the molar amounts of epoxy groups in epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber. The molar ratio of 5-chlorosulfonyl-2-hydroxybenzoic acid to maleic anhydride in maleic anhydride-grafted polyethylene was 1:1.

[0038] Comparative Example 1

[0039] The modified manganese slag in this comparative example was prepared by a method including the following steps:

[0040] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 100°C, stir and react for 15 h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.5:60, the average particle size of manganese slag is 10 μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0041] (2) Maleic anhydride-grafted polyethylene (the same maleic anhydride-grafted polyethylene used in Example 1) and epoxy-modified manganese slag are mixed evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 200°C to obtain polyethylene-grafted manganese slag. The polyethylene-grafted manganese slag and 5-chlorosulfonyl-2-hydroxybenzoic acid are mixed evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 200°C to obtain surface-functionalized manganese slag with an average particle size of 1.8 mm. The molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is equal to the molar amount of epoxy in the epoxy-modified manganese slag. The ratio of the molar amount of 5-chlorosulfonyl-2-hydroxybenzoic acid to the molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is 1:1.

[0042] (3) The surface-functionalized manganese slag, basalt fiber (the same basalt fiber as used in Example 1) and nano-alumina fiber (the same nano-alumina fiber as used in Example 1) are stirred evenly to obtain modified manganese slag; wherein, the mass ratio of the manganese slag, the basalt fiber and the nano-alumina fiber used in preparing the surface-functionalized manganese slag is 1:0.5:0.1.

[0043] Comparative Example 2

[0044] The modified manganese slag in this comparative example was prepared by a method including the following steps:

[0045] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 100°C, stir and react for 15 h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.5:60, the average particle size of manganese slag is 10 μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0046] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 3:80:12 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 5, stir for 45 min, then add nano alumina fiber (the same nano alumina fiber used in Example 1) to the reactor, heat to 65°C, stir for 10 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified nano alumina fiber; wherein, the mass ratio of nano alumina fiber and epoxy silane coupling agent is 1:0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0047] (3) Maleic anhydride-grafted polyethylene (the grafting rate of maleic anhydride-grafted polyethylene is 1.2%, and the melt index tested at a temperature of 190℃ and a load of 2.16kg is 0.8~1.0g / 10min), epoxy-modified manganese slag and epoxy-modified nano-alumina fiber are stirred evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 200℃ to obtain polyethylene-grafted manganese slag-multi-component fiber composite. Then, the polyethylene-grafted manganese slag-multi-component fiber composite and 5-chlorosulfonyl-2-hydroxybenzoic acid are added. After being mixed evenly, the mixture was added to a twin-screw extruder and melt-extruded and granulated at 200°C to obtain modified manganese slag with an average particle size of 1.8 mm. The mass ratio of epoxy-modified manganese slag to epoxy-modified nano-alumina fiber was 1:0.6. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene was equal to the sum of the molar amounts of epoxy groups in epoxy-modified manganese slag and epoxy-modified nano-alumina fiber. The molar ratio of 5-chlorosulfonyl-2-hydroxybenzoic acid to maleic anhydride in maleic anhydride-grafted polyethylene was 1:1.

[0048] Comparative Example 3

[0049] The modified manganese slag in this comparative example was prepared by a method including the following steps:

[0050] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 100°C, stir and react for 15 h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.5:60, the average particle size of manganese slag is 10 μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0051] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2:70:8 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 4, stir for 30 min, then add basalt fiber (the same basalt fiber used in Example 1) to the reactor, heat to 65°C, stir for 7 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified basalt fiber; wherein, the mass ratio of basalt fiber and epoxy silane coupling agent is 1:0.7, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0052] (3) Maleic anhydride-grafted polyethylene (with a grafting rate of 1.2%, and a melt index of 0.8~1.0 g / 10 min tested at 190℃ and a load of 2.16 kg), epoxy-modified manganese slag, and epoxy-modified basalt fiber were stirred evenly and then added to a twin-screw extruder. The mixture was melt-extruded and granulated at 200℃ to obtain a polyethylene-grafted manganese slag-multi-component fiber composite. The polyethylene-grafted manganese slag-multi-component fiber composite and 5-chlorosulfonyl-2-hydroxybenzoic acid were then added to the mixture. After being thoroughly mixed with acid, the mixture was added to a twin-screw extruder and melt-extruded and granulated at 200°C to obtain modified manganese slag with an average particle size of 1.8 mm. The mass ratio of epoxy-modified manganese slag to epoxy-modified basalt fiber was 1:0.6. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene was equal to the sum of the molar amounts of epoxy groups in epoxy-modified manganese slag and epoxy-modified basalt fiber. The molar ratio of 5-chlorosulfonyl-2-hydroxybenzoic acid to maleic anhydride in maleic anhydride-grafted polyethylene was 1:1.

[0053] Comparative Example 4

[0054] The modified manganese slag in this comparative example was prepared by a method including the following steps:

[0055] (1) Add manganese slag, epoxy silane coupling agent and toluene into a reactor, heat to 100°C, stir and react for 15 h, filter, wash the filter cake with ethanol, and dry to obtain epoxy-modified manganese slag; wherein, the mass ratio of manganese slag, epoxy silane coupling agent and toluene is 1:0.5:60, the average particle size of manganese slag is 10 μm, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0056] (2) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 2:70:8 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 4, stir for 30 min, then add basalt fiber (the same basalt fiber used in Example 1) to the reactor, heat to 65°C, stir for 7 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified basalt fiber; wherein, the mass ratio of basalt fiber and epoxy silane coupling agent is 1:0.7, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0057] (3) Add epoxy silane coupling agent, ethanol and deionized water in a mass ratio of 3:80:12 to the reactor, then add acetic acid to adjust the pH of the material in the reactor to 5, stir for 45 min, then add nano alumina fiber (the same nano alumina fiber used in Example 1) to the reactor, heat to 65°C, stir for 10 h, filter, wash the filter cake with ethanol and deionized water in sequence, and dry to obtain epoxy modified nano alumina fiber; wherein, the mass ratio of nano alumina fiber and epoxy silane coupling agent is 1:0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0058] (4) Maleic anhydride-grafted polyethylene (the grafting rate of maleic anhydride-grafted polyethylene is 1.2%, and the melt index tested at a temperature of 190℃ and a load of 2.16kg is 0.8~1.0g / 10min), epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber are stirred evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 200℃ to obtain modified manganese slag with an average particle size of 1.8mm. The mass ratio of epoxy-modified manganese slag, epoxy-modified nano-alumina fiber and epoxy-modified basalt fiber is 1:0.1:0.5. The molar amount of maleic anhydride in maleic anhydride-grafted polyethylene is equal to the sum of the molar amount of epoxy groups in epoxy-modified manganese slag, epoxy groups in epoxy-modified nano-alumina fiber and epoxy groups in epoxy-modified basalt fiber.

[0059] II. Specific embodiments of the application of the modified manganese slag of the present invention in the preparation of cement materials are as follows:

[0060] The modified manganese slag from Examples 1-3 can be added to cement slurry as a solid filler to prepare cement materials.

[0061] Experimental Example

[0062] To evaluate the application effect of modified manganese slag in cement materials of Examples 1-3 and Comparative Examples 1-4, cement powder, modified manganese slag, standard sand, and tap water were mixed evenly in a mass ratio of 100:15:300:45 to obtain cement mortar. The cement mortar was then poured into molds, placed on a vibrating table, and vibrated for 1 minute. The surface of the test blocks was then smoothed, covered with plastic film, and demolded after 24 hours. The blocks were then cured in a standard curing room at 25°C and 95% relative humidity for 28 days to obtain test samples. The flexural strength and compressive strength were then tested according to the method in standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar". Finally, the test samples were tested according to standard GB / T The thermal conductivity was tested using the method described in 32064-2015. The test samples were then subjected to freeze-thaw cycles, each lasting 4 hours. After the set number of cycles was reached, the compressive strength of the samples was measured. The ratio of the decrease in compressive strength before and after the freeze-thaw cycles to the initial compressive strength was calculated to obtain the strength loss rate. Finally, the test samples were immersed in deionized water at 25°C for 30 hours. After 30 hours, they were broken and the water penetration depth on the fracture surface was measured. Tests were conducted at five identical test points on each sample, and the average value was calculated. Simultaneously, samples with modified manganese slag replaced by cement powder were used as blank controls. The test results for flexural strength, compressive strength, thermal conductivity, strength loss rate, and water penetration depth of cement materials prepared with different modified manganese slags are shown in Table 1.

[0063] Table 1. Flexural strength, compressive strength, thermal conductivity, strength loss rate, and water penetration depth of cement materials.

[0064]

[0065] As can be seen from the test results in Table 1, the cement slurry material prepared by the modified manganese slag of the present invention has good flexural strength, compressive strength and freeze-thaw resistance, and has low thermal conductivity and water penetration depth.

[0066] As can be seen from Example 1 and Comparative Examples 1-3, the modified manganese slag prepared in Example 1 is more beneficial to improving the performance of cement materials compared to Comparative Examples 1-3. The reasons may be as follows: Simultaneously, basalt fibers and nano-alumina fibers are chemically bonded to manganese slag through polyethylene long chains to form a composite, which can improve the dispersion uniformity of basalt fibers, nano-alumina fibers, and manganese slag. Basalt fibers and nano-alumina fibers can play an anchoring role in cement materials, improving the flexural strength and low-temperature freeze-thaw resistance of the cement materials. When larger basalt fibers and smaller nano-alumina fibers are used together, the anchoring effect is stronger, and fibers of different sizes can prevent the propagation of cracks of different sizes, further improving the flexural strength of the cement materials. Furthermore, when using polyethylene-grafted manganese slag alone, or when using basalt fibers or nano-alumina fibers to modify manganese slag, the compressive strength of the cement materials is lower than that of pure cement materials. Only when using basalt fibers and nano-alumina fibers to modify manganese slag does the compressive strength of the cement materials exceed that of pure cement materials. The uniform dispersion of basalt fiber and nano-alumina fiber, as well as the network structure formed by the chemical bonding of hydrophobic polyethylene molecular chains in modified manganese slag, basalt fiber, and nano-alumina fiber, can effectively improve the waterproof and permeability performance of cement materials and reduce the depth of water seepage.

[0067] As shown in Example 1 and Comparative Example 4, further melt extrusion of the polyethylene-grafted manganese slag-multi-component fiber composite with 5-chlorosulfonyl-2-hydroxybenzoic acid can further improve the flexural strength, compressive strength, and freeze-thaw resistance of cement materials, and further reduce the thermal conductivity and water penetration depth of cement materials. The reasons may be as follows: When the polyethylene-grafted manganese slag-multi-component fiber composite is further melt extruded with 5-chlorosulfonyl-2-hydroxybenzoic acid, 5-chlorosulfonyl-2-hydroxybenzoic acid reacts chemically with the hydroxyl groups in the polyethylene-grafted manganese slag-fiber composite through sulfonyl chloride, which can graft carboxyl and phenolic hydroxyl groups onto the surface of the modified manganese slag, thereby improving the dispersibility of the modified manganese slag and thus enhancing the contact area between the modified manganese slag and the components in the cement slurry. Moreover, the modified manganese slag can combine with the components in the cement slurry through hydrogen bonding and other interactions via carboxyl and phenolic hydroxyl groups, thereby improving the strength and freeze-thaw resistance of cement materials. Furthermore, with improved dispersibility, low thermal conductivity materials (such as basalt fibers) are dispersed more uniformly, effectively blocking the formation of heat pathways and thus reducing the thermal conductivity of cement materials. The prepared modified manganese slag has a richer variety of anionic groups on its surface, which enhances its surface activity, resulting in greater strength and lower thermal conductivity.

[0068] It should be noted that, in this document, the terms "comprising," "including," and any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Specific examples have been used in this document to illustrate the principles and implementation methods of the present invention. These examples are merely for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be pointed out that, due to the limitations of written expression and the objective existence of infinite specific structures, those skilled in the art can make several improvements, modifications, or variations without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, variations, or combinations, or the direct application of the concept and technical solution of the present invention to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A modified manganese slag, characterized in that, The product is prepared by a method comprising the following steps: maleic anhydride-grafted polyethylene, epoxy-modified manganese slag, epoxy-modified nano-alumina fiber, and epoxy-modified basalt fiber are mixed and melt-extruded to obtain a polyethylene-grafted manganese slag-multi-component fiber composite; the polyethylene-grafted manganese slag-multi-component fiber composite is then mixed with 5-chlorosulfonyl-2-hydroxybenzoic acid and melt-extruded to obtain modified manganese slag; the mass ratio of the epoxy-modified manganese slag, epoxy-modified nano-alumina fiber, and epoxy-modified basalt fiber is 1:0.1~0.2:0.3~0.5; the molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is equal to the sum of the molar amounts of epoxy groups in the epoxy-modified manganese slag, epoxy-modified nano-alumina fiber, and epoxy-modified basalt fiber; the molar ratio of the molar amount of 5-chlorosulfonyl-2-hydroxybenzoic acid to the molar amount of maleic anhydride in the maleic anhydride-grafted polyethylene is 1:

1.

2. The modified manganese slag according to claim 1, characterized in that, The preparation method of the epoxy-modified manganese slag is as follows: manganese slag and γ-(2,3-epoxypropoxy)propyltrimethoxysilane are mixed and reacted in a solvent at 100~105℃ for 12~15h to obtain epoxy-modified manganese slag; the mass ratio of manganese slag and γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 1:0.5~0.

8.

3. The modified manganese slag according to claim 2, characterized in that, The average particle size of the manganese slag is 10~20μm.

4. The modified manganese slag according to claim 2, characterized in that, The chemical composition of the manganese slag is as follows: SiO2 31.5wt%, CaO 37.1wt%, F2O3 3.9wt%, Al2O3 10.2wt%, MgO 4.1wt%, SO3 5.8wt%, MnO 3.3wt%, and loss on ignition 4.1wt%.

5. The modified manganese slag according to claim 1, characterized in that, The preparation method of the epoxy-modified nano-alumina fiber is as follows: Epoxy silane coupling agent, ethanol and water are mixed in a mass ratio of 2~3:70~80:8~12, and the pH is adjusted to 4~5 with acetic acid. After mixing for 30~45 min, nano-alumina fiber is added, and the mixture is heated to 65~70℃ and reacted for 10~12 h to obtain epoxy-modified nano-alumina fiber; the mass ratio of nano-alumina fiber to epoxy silane coupling agent is 1:0.9~1.1, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

6. The modified manganese slag according to claim 5, characterized in that, The nano-alumina fibers have an average diameter of 5-10 nm and an average length of 8-15 nm.

7. The modified manganese slag according to claim 1, characterized in that, The preparation method of the epoxy-modified basalt fiber is as follows: Epoxy silane coupling agent, ethanol and water are mixed in a mass ratio of 2~3:70~80:8~12, and the pH is adjusted to 4~5 with acetic acid. The mixture is stirred for 30~45 min, then basalt fiber is added, heated to 65~70℃, and the mixture is reacted for 7~9 h to obtain epoxy-modified basalt fiber; the mass ratio of basalt fiber to epoxy silane coupling agent is 1:0.7~0.9, and the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

8. The modified manganese slag according to claim 7, characterized in that, The basalt fibers have an average diameter of 5-10 μm and an average length of 0.2-0.6 mm.

9. The modified manganese slag according to claim 1, characterized in that, The maleic anhydride-grafted polyethylene has a grafting rate of 1.2-1.5%, a melt index of 0.8-1.0 g / 10 min tested at a temperature of 190℃ and a load of 2.16 kg, a melt extrusion temperature of 200-220℃, and an average particle size of 1.8-2.5 mm for the modified manganese slag.

10. The application of the modified manganese slag as described in any one of claims 1-9 in the preparation of cement materials.

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