Magnesium oxychloride cement mortar containing polyaluminum chloride water purifying agent waste residues as well as preparation method and application of magnesium oxychloride cement mortar

Abstract

The invention belongs to the technical field of building materials, and particularly relates to magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residues as well as a preparation method and application of the magnesium oxychloride cement mortar. The magnesium oxychloride cement mortar containing the polyaluminum chloride water purifying agent waste residues is prepared from the following components in parts by mass: 45 to 55 parts of magnesium oxychloride cement and gypsum, 100 to 150 parts of the polyaluminum chloride water purifying agent waste residues, 0 to 3.6 parts of citric acid, 0 to 14 parts of styrene-acrylic emulsion, 130 to 170 parts of river sand and 160 to 200 parts of water, the magnesium oxychloride cement is prepared from 480 to 520 parts of magnesium oxide and 190 to 320 parts of magnesium chloride hexahydrate. The magnesium oxychloride cement mortar containing the polyaluminum chloride water purifying agent waste residues can be used as a cement-based pavement patching material, a large amount of polyaluminum chloride water purifying agent waste residues can be consumed, the problem of environmental pollution caused by the waste residues is effectively solved, the water resistance of the magnesium oxychloride cement mortar can be effectively improved, and efficient resource utilization of industrial solid waste is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue, and a preparation method and application thereof. Background Art

[0002] my country's road construction has achieved remarkable results, and the total mileage of highways has increased rapidly. In the future, there will be a period of rapid growth in maintenance and repair. The development of high-performance pavement repair materials will produce good social and economic benefits. At present, common inorganic pavement repair materials are silicate cement mortar, phosphate cement mortar, etc. Among them, silicate cement has the disadvantages of large shrinkage and low adhesion. Phosphate cement is relatively brittle, and the raw material price is relatively expensive, and the cost is too high. Although pavement repair materials containing organic materials such as resins have good mechanical properties, they are prone to aging and deterioration. Therefore, the development of a green, high-performance inorganic pavement repair material that can effectively make up for the defects of the existing technology will have broad application prospects.

[0003] Polyaluminium chloride is currently recognized as an excellent water purifier and is widely used in water purification. The main raw materials for the production of polyaluminium chloride are light-burned bauxite, calcium aluminate powder and hydrochloric acid. Due to its advantages of low production cost and good water purification effect, its demand is huge. However, when polyaluminium chloride water purifier is produced, a large amount of sticky and acidic industrial solid waste will be generated. At present, most of its treatment methods are on-site landfill, which will cause serious pollution to the surrounding soil and water bodies. Therefore, the efficient resource utilization of polyaluminium chloride water purifier waste residue has become an effective way to solve its environmental pollution.

[0004] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0005] The object of the present invention is to provide a magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue and a preparation method and application thereof, so as to help solve the problem that polyaluminium chloride water purifier waste residue is easy to cause environmental pollution and / or the performance of cement-based road repair materials needs to be improved.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical scheme: a magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue, wherein the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue comprises, by weight, magnesium oxychloride cement, 45-55 parts of gypsum, 100-150 parts of polyaluminum chloride water purifier waste residue, 0-3.6 parts of citric acid and 0-14 parts of styrene-acrylic emulsion, 130-170 parts of river sand and 160-200 parts of water; the magnesium oxychloride cement comprises 480-520 parts of magnesium oxide and 190-320 parts of magnesium chloride hexahydrate.

[0007] Preferably, in terms of mass fractions, the magnesium oxychloride cement includes 500 parts of magnesium oxide and 311 parts of magnesium chloride hexahydrate, the amount of the gypsum is 50 parts, the amount of the river sand is 150 parts, and the amount of water is 188 parts.

[0008] Preferably, the amount of citric acid used is 1.8-3.6 parts, and the amount of styrene acrylic emulsion used is 7-14 parts.

[0009] Preferably, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue further comprises, by weight: 3-12 parts of polyethylene fiber; the length of the polyethylene fiber is ≥12 mm, the elastic modulus is ≥120 GPa, and the breaking strength is ≥3.1 GPa.

[0010] Preferably, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue further comprises, by weight: 0-1 part of a water reducer and / or 0-1.5 parts of a thickener; the solid content of the water reducer is ≥25%, and the water reduction rate is ≥40%.

[0011] Preferably, the particle size of the polyaluminium chloride water purifier waste residue is ≤200 mesh, and is obtained after drying, grinding and sieving.

[0012] Preferably, the magnesium oxide is derived from light-burned magnesium oxide powder, the magnesium oxide content in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the magnesium chloride hexahydrate content is greater than or equal to 99%; and the particle size of the river sand is 0.2-0.8 mm.

[0013] The present invention also provides a method for preparing the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as described above, which adopts the following technical scheme: The method for preparing the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as described above comprises the following steps: (1) heating water, adding magnesium chloride hexahydrate until fully dissolved, removing insoluble matter, adding the citric acid and styrene acrylic emulsion, mixing evenly, and obtaining a prefabricated solution; (2) mixing magnesium oxide, gypsum, polyaluminium chloride water purifier waste residue and river sand evenly to obtain a mixed powder, adding the prefabricated solution to the mixed powder, stirring, and obtaining a mixed slurry, namely the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue. Preferably, in step (1), before adding the magnesium chloride hexahydrate, the water is heated to 55-65°C.

[0014] Preferably, in step (1), after removing the insoluble matter, the step further includes adding a water reducing agent and / or a thickener; after step (2), the step further includes adding polyethylene fibers to the mixed slurry and mixing them evenly (the polyethylene fibers are added to the mixed slurry in small amounts and multiple times).

[0015] The present invention also provides the application of the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier as described above, which adopts the following technical scheme: the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier as described above is used as a cement-based pavement repair material.

[0016] Beneficial effects:

[0017] (1) The citric acid, styrene-acrylic emulsion and polyaluminium chloride water purifier waste residue in the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention are added to magnesium oxychloride cement to effectively improve the disadvantage of poor water resistance of magnesium oxychloride cement. The specific effects are as follows: SiO2 and Al2O3 in the polyaluminium chloride water purifier waste residue will react with Mg in magnesium oxychloride cement. 2+ The insoluble amorphous gel is generated, which can fill the gaps in magnesium oxychloride cement and wrap the main strength phase to prevent the main strength phase from hydrolyzing, thereby improving the water resistance of magnesium oxychloride cement. Citric acid can change the crystal form of the main strength phase, making it more compact, reducing the pores and thus improving the water resistance; styrene-acrylic emulsion will form a protective film on the surface of the main strength phase to improve the water resistance of magnesium oxychloride cement; at the same time, the initial setting time of magnesium oxychloride cement mortar mixed with citric acid, styrene-acrylic emulsion, and polyaluminium chloride water purifier waste can be generally controlled at about 3 hours.

[0018] (2) The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue obtained by the present invention improves the brittleness of magnesium oxychloride cement. The specific effects are as follows: the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue mixed with polyethylene fiber is made into a thin plate, which will not be directly broken after the initial fracture, but with the increase of loading time, the load and deflection of the thin plate will show a trend of gradual increase, and strain hardening characteristics will appear. This is because the bridging effect between the polyethylene fiber and the magnesium oxychloride cement mortar matrix containing polyaluminium chloride water purifier waste residue inhibits the fracture of the thin plate.

[0019] (3) The water reducing agent in the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention can improve the fluidity while ensuring the strength of the cement matrix. The thickener used in the present invention can increase the consistency of the slurry, which is conducive to the uniform dispersion of polyethylene fibers and prevents water bleeding.

[0020] (4) The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention is used to prepare high-toughness cement-based pavement repair materials, which can not only absorb a large amount of polyaluminium chloride water purifier waste residue and effectively solve the environmental pollution problem caused by the waste residue, but also effectively improve the water resistance and volume stability of the high-toughness cement-based pavement repair materials, thereby realizing the efficient resource utilization of the industrial solid waste and generating good social benefits.

[0021] (5) The preparation method of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention is simple, and the prepared mortar has high strength, low cost, fast production speed, convenient construction and its use is not limited to road repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0023] Figure 1 The load-deflection curve diagram of magnesium oxychloride cement mortar provided in the embodiments of the present invention and the comparative examples;

[0024] Figure 2 These are the SEM images of two magnesium oxychloride cement mortars before and after immersion in water;

[0025] Figure 3 It is the load-deflection curve of the modified ASTM C108 toughness index method. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0027] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0028] The invention aims at the problem that the current on-site burial of polyaluminium chloride water purifier waste residue easily causes pollution to the surrounding soil and water bodies and / or the performance of cement-based road repair materials needs to be improved, and provides a magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue.

[0029] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the embodiment of the present invention includes, by weight, magnesium oxychloride cement, 45-55 parts (for example, 45 parts, 47 parts, 50 parts, 52 parts and 55 parts) of gypsum, 100-150 parts (for example, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts or 150 parts) of polyaluminum chloride water purifier waste residue, 3-12 parts (for example, 3 parts, 5 parts, 7 parts, 9 parts, 11 parts or 12 parts) of polyethylene fiber, 0-3.6 parts (for example, 0.5 parts, 1 parts, 1.5 parts) of citric acid. The magnesium oxychloride cement comprises 480-520 parts (for example, 480 parts, 500 parts or 520 parts) of magnesium oxide and 190-320 parts (for example, 190 parts, 310 parts or 320 parts) of magnesium chloride hexahydrate. Among them, if the dosage of citric acid and / or styrene-acrylic emulsion is too large, although the water resistance of magnesium oxychloride cement can be improved well, the matrix strength of cement will be significantly reduced; the addition of gypsum can make magnesium oxychloride cement have micro-expansion, thereby making the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention more suitable for use as a road repair material, avoiding the cracking or fissures of the repaired road surface caused by the shrinkage of silicate cement repair materials.

[0030] Magnesium oxychloride cement has excellent properties such as high early strength, fast setting and hardening, high wear resistance, and good bonding performance, but it has poor water resistance and high brittleness, making it difficult to be used directly as a cement-based road repair material. The inventor found in the research that Cl in the waste residue of polyaluminium chloride water purifier - The content is 2.25%, while magnesium oxychloride cement itself contains Cl - , there is no need to dechlorinate the polyaluminium chloride water purifier waste residue, which is quite suitable. The present invention adds the polyaluminium chloride water purifier waste residue into magnesium oxychloride cement, which can effectively improve the disadvantage of poor water resistance of magnesium oxychloride cement (SiO2 and Al2O3 in the polyaluminium chloride water purifier waste residue will react with Mg in magnesium oxychloride cement). 2+ It generates an insoluble amorphous gel, which can fill the gaps in magnesium oxychloride cement and wrap the main strength phase to prevent the main strength phase from hydrolyzing, thereby improving the water resistance of magnesium oxychloride cement).

[0031] In addition, adding citric acid and styrene-acrylic emulsion to the system can further improve water resistance (wherein, citric acid can change the crystal form of the main strength phase, making it more compact, reducing pores and thus improving water resistance; styrene-acrylic emulsion can form a protective film on the surface of the main strength phase to improve the water resistance of magnesium oxychloride cement). The addition of citric acid, styrene-acrylic emulsion and polyaluminum chloride water purifier waste residue to the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention can also help control the initial setting time of the mortar of the present invention to about 3 hours overall, making it more suitable for use as a road repair material.

[0032] The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue provided by the present invention has not only excellent comprehensive performance and low production cost, but also can consume a large amount of polyaluminium chloride water purifier waste residue, which not only reduces the engineering cost but also saves resources and energy, and has significant social and economic benefits.

[0033] In a preferred embodiment of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention, the magnesium oxychloride cement includes 500 parts of magnesium oxide and 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum, 150 parts of river sand and 188 parts of water, calculated by weight.

[0034] In a preferred embodiment of the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention, the amount of citric acid is 1.8-3.6 parts (for example, 1.8 parts, 2.1 parts, 2.4 parts, 2.7 parts, 3 parts, 3.3 parts or 3.6 parts), and the amount of styrene acrylic emulsion is 7-14 parts (for example, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts).

[0035] According to the mass fraction, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue also includes: 3-12 parts of polyethylene fiber (for example, 3 parts, 5 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts); the length of the polyethylene fiber is ≥12mm, the elastic modulus is ≥120GPa, and the fracture strength is ≥3.1GPa. The present invention can effectively improve the brittleness of magnesium oxychloride cement by adding polyethylene fiber to the magnesium oxychloride cement sand containing polyaluminium chloride water purifier waste residue: the incorporation of polyethylene fiber helps to make the cement-based pavement repair material of the embodiment of the present invention not directly disconnected after the initial fracture, and strain hardening characteristics appear; this is because the bridging effect between the polyethylene fiber and the polyaluminium chloride water purifier waste residue and the magnesium oxychloride cement matrix inhibits the fracture. If the length, elastic modulus and fracture strength of the polyethylene fiber do not meet the above requirements, the bending fracture of the specimen only shows a single crack effect, and the toughness of the specimen cannot be effectively improved. If the dosage of polyethylene fiber is too small, its effect on improving the fracture toughness of magnesium oxychloride cement is small.

[0036] In a preferred embodiment of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue further comprises, by weight: 0-1 part of water reducer (for example, 0.1 part, 0.3 part, 0.5 part, 0.8 part, 0.9 part or 1 part) and / or 0-1.5 parts of thickener (for example, 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1.1 part, 1.3 part or 1.5 parts); the solid content of the water reducer is ≥25%, and the water reduction rate is ≥40%. Among them, the water reducer helps to improve the fluidity on the basis of ensuring the strength of the cement-based road repair material; the thickener can play a role in increasing the consistency of the slurry, which is conducive to the uniform dispersion of polyethylene fibers so that it does not produce water bleeding.

[0037] In a preferred embodiment of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention, magnesium oxide comes from light-burned magnesium oxide powder, the content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is greater than or equal to 99%; and the particle size of river sand is 0.2-0.8 mm.

[0038] In a preferred embodiment of the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention, the particle size of the polyaluminum chloride water purifier waste residue is ≤200 mesh (i.e., it can pass through a 200 mesh sieve), and is obtained after drying (removing moisture from the polyaluminum chloride water purifier waste residue to facilitate subsequent grinding thereof), grinding and sieving. Among them, the drying method can be heating drying; for example, high-temperature calcination at 600°C for 1h; or, it can also be dried at 110°C for 10h, etc., as long as the drying of polyaluminum chloride can be achieved. In addition, heating also helps to remove other impurities (for example, paper scraps, etc.) mixed in the polyaluminum chloride water purifier waste residue.

[0039] The present invention also proposes a method for preparing the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue as described above. The method for preparing the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue in the embodiment of the present invention comprises the following steps: (1) heating water and adding magnesium chloride hexahydrate until it is fully dissolved, removing insoluble matter and adding citric acid and styrene acrylic emulsion, mixing uniformly to obtain a prefabricated solution; (2) mixing magnesium oxide, gypsum, polyaluminum chloride water purifier waste residue and river sand uniformly to obtain a mixed powder, adding the prefabricated solution to the mixed powder, stirring to obtain a mixed slurry, which is the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention.

[0040] The preparation method of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention is simple, the prepared cement-based road repair material has high strength, low cost, fast production speed, and convenient construction, and its use is not limited to road repair.

[0041] In a preferred embodiment of the method for preparing magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention, in step (1), before adding magnesium chloride hexahydrate, water is heated to 55-65°C (for example, 55°C, 58°C, 60°C, 62°C or 65°C).

[0042] In a preferred embodiment of the method for preparing magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention, in step (1), after removing the insoluble matter, it also includes the step of adding a water reducer and / or a thickener; after step (2), it also includes the step of adding polyethylene fiber to the mixed slurry and mixing it evenly (for example, the polyethylene fiber can be added to the mixed slurry in small amounts and multiple times).

[0043] The present invention also proposes the use of the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier as described above, and the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier is used as a cement-based road repair material. Specifically, when the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier of the present invention is used to repair the damaged road surface, after the damaged road surface is excavated, the magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier of the present invention is directly poured on the road surface repair position and smoothed.

[0044] The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present invention and its preparation method and application are described in detail below through specific embodiments.

[0045] In the following embodiments: the MgO content in the light-burned magnesium oxide is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the waste residue of polyaluminium chloride water purifier comes from a water purifier manufacturer in Gongyi City, Henan Province; citric acid is purchased from Shanghai Guoyao Chemical Reagent Shanghai Test; styrene-acrylic emulsion is purchased from Shandong Yousuo Chemical Technology Co., Ltd.; the water reducer (polycarboxylic acid water reducer) has a solid content of not less than 25.2% and a water reduction rate of not less than 47%, purchased from Dongfang Tongren; the thickener (hydroxypropyl methylcellulose) is purchased from Hongsheng Chemical; and the polyethylene fiber is purchased from Sinopec Yizheng Co., Ltd. (the length of the polyethylene fiber is 12 mm, the elastic modulus is ≥120 GPa, and the breaking strength is ≥3.1 GPa).

[0046] Example 1

[0047] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water and 100 parts of polyaluminum chloride water purifier waste residue.

[0048] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the waste residue of polyaluminium chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0049] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0050] (1) Solution preparation: Weighed magnesium chloride hexahydrate and water (60° C.) were fully dissolved and allowed to stand for 1 day. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, the upper clear liquid of the solution after standing was taken to obtain a pre-made solution.

[0051] (2) Slurry preparation: Lightly burned magnesium oxide powder, fine river sand, gypsum powder and polyaluminium chloride water purifier waste residue are stirred at low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at low speed for 6 minutes to obtain magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment, which is recorded as S0.

[0052] Example 2

[0053] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid and 7 parts of styrene-acrylic emulsion.

[0054] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0055] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0056] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid after standing. Add citric acid and styrene-acrylic emulsion into the clear liquid and stir evenly to obtain a pre-made solution.

[0057] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain the polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry of this embodiment, which is recorded as S1.

[0058] Example 3

[0059] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of magnesium oxide, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 3.6 parts of citric acid and 14 parts of styrene-acrylic emulsion.

[0060] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the waste residue of polyaluminium chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve to obtain the obtained product.

[0061] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0062] (1) Solution preparation: Weigh magnesium chloride hexahydrate and water (60°C) and fully dissolve them and let them stand for 1 day. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid after standing, add citric acid and styrene-acrylic emulsion into the clear liquid and stir evenly to obtain a pre-made solution.

[0063] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment, which is recorded as S2.

[0064] Example 4

[0065] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue in this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid, 7 parts of styrene-acrylic emulsion and 3 parts of polyethylene fiber.

[0066] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0067] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0068] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid after the solution is left to stand; add citric acid and styrene-acrylic emulsion into the clear liquid and stir evenly to obtain a pre-made solution.

[0069] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain a mixed slurry (polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry).

[0070] (3) Fiber incorporation: Add a small amount of weighed polyethylene fiber evenly to the mixed slurry several times and stir at high speed for 6 minutes to observe whether the polyethylene fiber is evenly distributed in the slurry and does not clump. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment is obtained, which is recorded as M0.

[0071] The high magnesium oxychloride cement mortar containing the waste residue of polyaluminium chloride water purifier of this embodiment can be used as cement-based pavement repair material.

[0072] Example 5

[0073] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid, 7 parts of styrene-acrylic emulsion, 0.25 parts of polycarboxylic acid water reducer, 0.5 parts of hydroxypropyl methylcellulose and 6 parts of polyethylene fiber.

[0074] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0075] The method for preparing magnesium oxychloride cement-based waste residue containing polyaluminium chloride water purifier of the present embodiment comprises the following steps:

[0076] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid of the solution after standing. Add citric acid, styrene-acrylic emulsion, polycarboxylic acid water reducer and hydroxypropyl methylcellulose into the clear liquid and stir evenly to obtain a pre-made solution.

[0077] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain a mixed slurry (polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry).

[0078] (3) Fiber incorporation: Add weighed polyethylene fibers in small amounts and multiple times evenly into the mixed slurry and stir at high speed for 6 minutes to observe that the polyethylene fibers are evenly distributed in the slurry and do not clump. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment is obtained, which is recorded as M1.

[0079] Example 6

[0080] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid, 7 parts of styrene-acrylic emulsion, 0.6 parts of polycarboxylic acid water reducer, 1 part of hydroxypropyl methylcellulose and 9 parts of polyethylene fiber.

[0081] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0082] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0083] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid of the solution after standing. Add citric acid, styrene-acrylic emulsion, polycarboxylic acid water reducer and hydroxypropyl methylcellulose into the clear liquid and stir evenly to obtain a pre-made solution.

[0084] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain a mixed slurry (polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry).

[0085] (3) Fiber incorporation: Add the weighed polyethylene fibers evenly and in small amounts to the mixed slurry several times and stir at high speed for 6 minutes to observe that the polyethylene fibers are evenly distributed in the slurry and do not clump. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment is obtained, which is recorded as M2.

[0086] Example 7

[0087] A high-toughness cement-based road repair material magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue, the raw materials of which include, by weight: 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 100 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid, 7 parts of styrene-acrylic emulsion, 1 part of polycarboxylic acid water reducer, 1.5 parts of hydroxypropyl methylcellulose and 12 parts of polyethylene fiber.

[0088] Among them, the magnesium oxide content in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the magnesium chloride hexahydrate content is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600℃ for 1h, ground after cooling and passed through a 200-mesh sieve.

[0089] The preparation method of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of the present embodiment comprises the following steps:

[0090] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid after standing. Add citric acid, styrene-acrylic emulsion, polycarboxylic acid water reducer and hydroxypropyl methylcellulose into the clear liquid and stir evenly to obtain a pre-made solution.

[0091] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are stirred at a low speed to mix evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain a mixed slurry (polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry).

[0092] (3) Fiber incorporation: Add the weighed polyethylene fibers evenly and in small amounts to the mixed slurry several times and stir at high speed for 6 minutes to observe that the polyethylene fibers are evenly distributed in the slurry and do not clump. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment is obtained, which is recorded as M3.

[0093] Example 8

[0094] The magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of this embodiment includes, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand, 188 parts of water, 150 parts of polyaluminum chloride water purifier waste residue, 1.8 parts of citric acid, 7 parts of styrene-acrylic emulsion, 1 part of polycarboxylic acid water reducer, 1.5 parts of hydroxypropyl methylcellulose and 12 parts of polyethylene fiber.

[0095] The content of magnesium oxide in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm; the solid content of polycarboxylic acid water reducer is not less than 25.2%, and the water reduction rate is not less than 47%; the waste residue of polyaluminum chloride water purifier is calcined at 600°C for 1h, ground after cooling and passed through a 200-mesh sieve.

[0096] The preparation method of the waste residue magnesium oxychloride cement mortar containing polyaluminium chloride water purifier of the present embodiment comprises the following steps:

[0097] (1) Solution preparation: Heat the weighed water to 60°C, then fully dissolve magnesium chloride hexahydrate and water and let it stand. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, take the upper clear liquid after standing. Add citric acid, styrene-acrylic emulsion, polycarboxylic acid water reducer and hydroxypropyl methylcellulose into the clear liquid and stir evenly to obtain a pre-made solution.

[0098] (2) Slurry preparation: Lightly burned magnesium oxide powder, gypsum powder, polyaluminium chloride water purifier waste residue and fine river sand are mixed at a low speed and stirred evenly, and the prefabricated solution is poured into the evenly mixed powder and stirred at a low speed for 6 minutes to obtain polyaluminium chloride water purifier waste residue magnesium oxychloride cement slurry.

[0099] (3) Fiber incorporation: Add weighed polyethylene fibers evenly and in small amounts to the slurry several times and stir at high speed for 6 minutes to observe that the fibers are evenly distributed in the slurry and do not agglomerate. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of this embodiment is obtained, which is recorded as M4.

[0100] Comparative Example 1

[0101] The raw materials of the magnesium oxychloride cement mortar of this comparative example include, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 150 parts of fine river sand and 188 parts of water.

[0102] Among them, the magnesium oxide content in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm;

[0103] The preparation method of the magnesium oxychloride cement mortar of this comparative example comprises the following steps:

[0104] (1) Solution preparation: Weighed magnesium chloride hexahydrate and water (60° C.) were fully dissolved and allowed to stand for 1 day. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, the upper clear liquid of the solution after standing was taken to obtain a pre-made solution.

[0105] (2) Slurry preparation: Lightly burned magnesium oxide powder and fine river sand are stirred at a low speed to be uniformly mixed, and the prefabricated solution is poured into the uniformly mixed powder and stirred at a low speed for 6 minutes to obtain magnesium oxychloride cement slurry, which is recorded as A0.

[0106] Comparative Example 2

[0107] The raw materials of the magnesium oxychloride cement mortar of this comparative example include, by weight, 500 parts of light-burned magnesium oxide powder, 311 parts of magnesium chloride hexahydrate, 50 parts of gypsum powder, 150 parts of fine river sand and 188 parts of water.

[0108] Among them, the magnesium oxide content in the light-burned magnesium oxide powder is greater than 86%, and the activity is greater than 60%; the content of magnesium chloride hexahydrate is not less than 99%; the particle size of fine river sand is 0.2-0.8mm;

[0109] The preparation method of the magnesium oxychloride cement mortar of this comparative example comprises the following steps:

[0110] (1) Solution preparation: Weighed magnesium chloride hexahydrate and water (60° C.) were fully dissolved and allowed to stand for 1 day. Since magnesium chloride hexahydrate contains a small amount of insoluble matter, the upper clear liquid of the solution after standing was taken to obtain a pre-made solution.

[0111] (2) Slurry preparation: Lightly burned magnesium oxide powder, fine river sand and gypsum powder are mixed uniformly at a low speed, and the prefabricated solution is poured into the uniformly mixed powder and stirred at a low speed for 6 minutes to obtain magnesium oxychloride cement slurry, which is recorded as B0.

[0112] Experimental example

[0113] 1. The performance of the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue of Examples 1-8 and the magnesium oxychloride cement mortar of Comparative Examples 1-2 were tested respectively.

[0114] Among them, the compressive strength is tested according to the Chinese standard GB / T 17671-1999;

[0115] The test method for water resistance coefficient is:

[0116]

[0117] In formula (1): R (28，0) - Compressive strength of specimens cured in air for 28 days; R (28，14) - Compressive strength of the specimens after air curing for 28 days and then immersion in water for 14 days.

[0118] Four-point bending test: The test adopts three-point loading, the span of the loading device is 100mm, and the span of the two bottom supports is 300mm. The loading method is displacement loading, and the loading rate is 0.5mm / min. A displacement sensor is placed at the bottom mid-span of the specimen to measure the deflection of the specimen.

[0119] The test method of bending toughness index is: This experiment uses the energy ratio method to calculate the bending toughness of the material. Figure 3As shown, the origin is O, and δ is the first crack point of the composite material, that is, the point where the load-deflection curve drops for the first time. The corresponding deflections and loads are recorded as A and B. 15.5 times, 25.5 times, and 50.5 times the first crack deflection δ are recorded as 15.5δ, 25.5δ, and 50.5δ, respectively, and their corresponding deflections and loads are recorded as C, D, E, F, G, and H. The ultimate mid-span deflection corresponding to the ultimate load is recorded as δ max , and the corresponding deflection and load are recorded as I and J. The area enclosed by the horizontal point coordinates and the load-deflection is the amount of energy absorbed by the material. Among them, the area enclosed by the curve OB and the horizontal axis OA. Among them, the area enclosed by the curve OB and the horizontal axis OA is the energy absorbed when the material reaches the initial crack, recorded as E1. The areas enclosed by the curves OD, OF, OH, OJ and the horizontal axes OC, OE, OG, and OI are the areas when the material reaches 15.5δ, 25.5δ, 50.5δ, δ max The energy absorbed by 15.5 、E 25.5 、E 50.5 、E max The specific calculation formula of the bending toughness index is as follows:

[0120]

[0121] Volume stability test method: In this experiment, the expansion rate of the sample is used to characterize the volume stability, specifically in accordance with ASTM C1148.

[0122] The test results are shown in Table 1 and Figure 1 As shown:

[0123] Table 1

[0124]

[0125]

[0126] In the above table, F c is the compressive strength, f L is the first crack bending strength, δ L is the initial crack mid-span deflection, f M is the ultimate bending strength, δ M is the mid-span deflection corresponding to the ultimate bending strength, and I is the bending toughness index.

[0127] Note: Some articles will I 15.5 ,I 25.5 ,I 50.5 The corresponding values ​​are greater than 30, 50, and 100, respectively, and are defined as high-toughness materials. 15.5 <30, I 25.5 ,I 50.5are all greater than their corresponding indicators, and are also identified as high-strength and high-toughness materials. 15.5 ,I 25.5 ,I 50.5 All of them are greater than their corresponding indicators, which can indicate that the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue can be used to prepare high-strength and high-toughness specimens.

[0128] In the above embodiments, the 28d strength of the mortar is greater than 60MPa, and the greater the water resistance coefficient, the better the water resistance. As shown in Table 1, the addition of citric acid, styrene-acrylic emulsion, and polyaluminum chloride water purifier waste can fully improve the water resistance of the material (refer to S0, S1, S2 and B0). Combined with samples M0-M3, it can be seen that (in samples M0-M3, the amount of polycarboxylic acid water reducer and hydroxypropyl methylcellulose is set to achieve uniform dispersion of polyethylene fibers), as the amount of polyethylene fibers gradually increases, the compressive strength, initial crack flexural strength, ultimate flexural strength, mid-span deflection corresponding to the ultimate flexural strength, and the performance of the flexural toughness index gradually increase. Combining A0, B0 and S0, it can be seen that the addition of gypsum can play a certain role in improving the expansibility of the mortar, and the addition of polyaluminum chloride water purifier waste residue can avoid excessive expansibility of the mortar; thereby making the magnesium oxychloride cement mortar containing polyaluminum chloride water purifier waste residue of the present invention in a slightly expanded state, which is more suitable for use as a pavement repair material, and can be better filled in the area to be repaired on the pavement, avoiding the cracking or fissures of the repaired pavement caused by the shrinkage of silicate cement repair materials.

[0129] 2. Scanning electron microscope observation of the microstructure of magnesium oxychloride cement mortar S1 and B0 before and after immersion in water:

[0130] Test method: Take several block samples of 5mm to 10mm in size from the center of the crushed sample, air-dry and spray-gold the samples ("unimmersed" samples refer to samples obtained after curing for 28 days; "immersed" samples refer to samples first cured for 28 days and then immersed in water for 14 days), and use the S-4800-Ⅰ electron microscope of Hitachi, Japan to test the microscopic morphology of the samples.

[0131] SEM pictures Figure 2 As shown. Figure 2It can be seen that before B0 is immersed in water, the morphology of the 5 phases of magnesium oxychloride cement mortar is mainly short rod-shaped with large pores. After B0 is immersed in water, water quickly invades along the pores, and the 5 phases are hydrolyzed from short rods to needles, and the blocky 5 phases are hydrolyzed into flocculent 5 phases, accompanied by a large number of micropores. This is also the main reason for the decrease in the strength of magnesium oxychloride cement mortar after immersion in water. Compared with B0, before S1 is immersed in water, the short rod-shaped 5 phases become needle-shaped 5 phases, and the blocky 5 phases are formed by countless short columnar 5 phases that are closely crossed with each other, and the whole structure is more compact. After S1 is immersed in water, the 5 phases are almost not hydrolyzed. This is because citric acid can change the crystal morphology of the main strength phase, making it more compact, reducing pores and thus improving water resistance; styrene-acrylic emulsion will form a protective film on the surface of the main strength phase to improve the water resistance of magnesium oxychloride cement; SiO2 and Al2O3 in the waste residue of polyaluminum chloride water purifier will react with Mg in magnesium oxychloride cement. 2+ It generates an insoluble amorphous gel, which can fill the gaps in the magnesium oxychloride cement mortar and wrap the main strength phase to prevent the main strength phase from hydrolyzing, thereby improving the water resistance of the magnesium oxychloride cement.

[0132] In addition, it should be noted that when the setting time of the material is short, the preparation of the material needs to be carried out on site. The initial setting time of the magnesium oxychloride cement mortar containing the polyaluminum chloride water purifier waste residue of the present invention is generally controlled at about 3 hours, which can meet the demand for transportation in a short time and avoid the disadvantages of on-site construction.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue, characterized in that: The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue comprises, by weight: magnesium oxychloride cement, 45-55 parts of gypsum, 100-150 parts of polyaluminium chloride water purifier waste residue, 0-3.6 parts of citric acid and 0-14 parts of styrene-acrylic emulsion, 130-170 parts of river sand and 160-200 parts of water; The magnesium oxychloride cement comprises 480-520 parts of magnesium oxide and 190-320 parts of magnesium chloride hexahydrate.

2. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 1, characterized in that: The dosage of the citric acid is 1.8-3.6 parts, and the dosage of the styrene-acrylic emulsion is 7-14 parts.

3. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 1, characterized in that: Calculated by weight, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue further comprises: 3-12 parts of polyethylene fiber; The polyethylene fiber has a length of ≥12 mm, an elastic modulus of ≥120 GPa, and a breaking strength of ≥3.1 GPa.

4. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 3, characterized in that: The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue further comprises, by weight: 0-1 part of a water reducer and / or 0-1.5 parts of a thickener; The solid content of the water reducing agent is ≥25%, and the water reducing rate is ≥40%.

5. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 1, characterized in that: The particle size of the polyaluminium chloride water purifier waste residue is ≤200 meshes and is obtained after drying, grinding and sieving.

6. The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 1, characterized in that: The magnesium oxide is derived from light-burned magnesium oxide powder, wherein the magnesium oxide content in the light-burned magnesium oxide powder is greater than 86% and the activity is greater than 60%; The magnesium chloride hexahydrate content is ≥ 99%; The particle size of the river sand is 0.2-0.8 mm.

7. The method for preparing magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue according to any one of claims 1 to 6, characterized in that: The steps include: (1) heating water, adding magnesium chloride hexahydrate until fully dissolved, removing insoluble matter, adding the citric acid and styrene acrylic emulsion, and mixing well to obtain a prefabricated solution; (2) Magnesium oxide, gypsum, polyaluminium chloride water purifier waste residue and river sand are uniformly mixed to obtain a mixed powder, and the prefabricated solution is added to the mixed powder, and stirred to obtain a mixed slurry, namely, the magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue.

8. The method for preparing magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 7, characterized in that: In step (1), water is heated to 55-65° C. before adding the magnesium chloride hexahydrate.

9. The method for preparing magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in claim 7, characterized in that: In step (1), after removing the insoluble matter, the step of adding a water reducing agent and / or a thickening agent is also included; After step (2), the method further includes adding polyethylene fibers into the mixed slurry and mixing the mixture evenly.

10. The use of magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue as claimed in any one of claims 1 to 6, characterized in that: The magnesium oxychloride cement mortar containing polyaluminium chloride water purifier waste residue is used as cement-based road repair material.

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