A multi-component high-salt solid waste alkali salt high-toughness mortar material and preparation method thereof

Abstract

The present invention proposes a multi-component high-salt solid waste alkali salt high-toughness mortar material and a preparation method thereof, which belongs to the technical field of harmless and resource-based solid waste. The raw materials of the multi-component high-salt solid waste alkali salt high-toughness mortar material of the present invention include dry-mixed mortar material, shrinkage reducing agent, water reducing agent and fiber, and the fiber addition amount is 1.0-2.0% of the mass of the dry-mixed mortar; the dry-mixed mortar material includes 28-40 parts of aged mixture, 10-15 parts of industrial solid waste gypsum, 5-8 parts of light-burned magnesium oxide, 2-5 parts of high-alumina cement, 3-8 parts of rubber powder, and 30-40 parts of artificial fine sand by weight; the aged mixture includes 50-70 parts of fly ash and 30-50 parts of magnesite by weight, and also includes aluminum dihydrogen phosphate solution and phosphogypsum leachate. The prepared multi-component high-salt solid waste alkali salt high-toughness mortar material has the characteristics of high strength, good toughness, good heavy metal stability, etc., and can be used in municipal administration, transportation and other fields.

Description

Technical Field

[0001] The invention belongs to the technical field of harmless treatment and resource utilization of solid waste, and in particular relates to a multi-component high-salt solid waste alkali salt high-toughness mortar material and a preparation method thereof. Background Art

[0002] The existing domestic waste incineration fly ash treatment and disposal technologies mainly include solidification into hazardous waste landfills, stabilization for sanitary landfill and resource utilization. Commonly used solidification and stabilization technologies include cement solidification, melt solidification and chelation stabilization technology. After stabilization, the fly ash enters the landfill for disposal. Most hazardous waste treatment plants charge an entrance fee of more than 1,000 yuan per ton of fly ash. In some areas where disposal sites are scarce, the cost of hazardous waste disposal sites is as high as 3,000 yuan / ton. After strict pretreatment, it enters the domestic waste landfill for disposal, and the treatment cost is as high as 500 to 1,000 yuan / ton, which increases the treatment cost of domestic waste by 80 to 300 yuan / ton. Therefore, developing fly ash resource technology and reducing the cost of fly ash landfill are the current research hotspots and application mainstream development directions of incineration fly ash treatment and disposal technologies. Due to differences in production processes, the SiO2 and Al2O3 contents of grate furnace fly ash are generally less than 2%, and it contains a large amount of soluble salts such as NaCl, KCl and CaClOH, which seriously limits its use value as an auxiliary cementitious material for traditional Portland cement and geopolymer cement.

[0003] On the other hand, phosphogypsum is mainly composed of calcium sulfate, containing impurities such as P, F and other free acids. Long-term storage will pollute the soil and groundwater. This not only causes serious environmental problems, but also generates huge waste of resources. The management and utilization of phosphogypsum is a global problem. The average utilization rate of phosphogypsum in the world is only 4.5%, and the utilization efficiency and economic value are low.

[0004] The patent with application publication number CN106377867A discloses a heavy metal solidifier for waste incineration fly ash and a solidification method thereof. The solidifier includes an aluminum-rich high-silicon material and an alkaline activator. The calcium oxide, chloride and sulfide present in large quantities in the waste incineration fly ash react with the aluminum-rich high-silicon material to generate a hydration reaction of calcium silicate hydrate (CSH), calcium chloroaluminate (Friedel) phase and ettringite (AFt) phase system.

[0005] However, the above technology uses aluminosilicate as the main component. At present, domestic incinerators mainly use grate furnace incineration technology. The fly ash produced by the grate furnace has very little silicon and aluminum content. If the above technology is used, a large amount of aluminum-rich and high-silicon materials still need to be added, and this technology has limited stabilization effect on the large amount of soluble chloride salts in the fly ash. Summary of the invention

[0006] In view of the problems of difficulty in fly ash resource utilization and low utilization rate of phosphogypsum in the prior art, the present invention proposes a multi-element high-salt solid waste alkali salt high-toughness mortar material and a preparation method thereof. The method does not require pretreatment such as fly ash washing and phosphogypsum pH adjustment, and directly utilizes soluble chlorides in fly ash and sulfates in phosphogypsum to start the reaction under acidic conditions. By adjusting the proportion of raw materials, alkali salt stabilized binders such as 3Mg(OH)2·MgCl2·8H2O, 5Mg(OH)2·MgSO4·7H2O, and MgKPO4·6H2O are produced, so that the obtained mortar material has good mechanical properties and can be used for the solidification and stabilization of heavy metals such as Pb, Zn, Cd, and As.

[0007] To achieve the above-mentioned purpose, the present invention provides a multi-element high-salt solid waste alkali salt high-toughness mortar material, the raw materials of which include dry-mixed mortar material, shrinkage reducing agent, water reducing agent and fiber, and the fiber is added in an amount of 1.0-2.0% of the mass of the dry-mixed mortar material;

[0008] The dry mortar material includes, by weight: 28-40 parts of aged mixture, 10-15 parts of industrial solid waste gypsum, 5-8 parts of light-burned magnesium oxide, 2-5 parts of high-alumina cement, 3-8 parts of rubber powder, and 30-40 parts of artificial fine sand;

[0009] The aged mixture comprises 50-70 parts of fly ash and 30-50 parts of magnesite by weight, and also comprises aluminum dihydrogen phosphate solution and phosphogypsum leachate.

[0010] Furthermore, the fly ash is grate furnace fly ash, with a potassium content of ≥4wt% and a silicon content of ≤3wt%.

[0011] Furthermore, the total amount of the aluminum dihydrogen phosphate solution and the phosphogypsum leachate added is 80-100% of the total mass of the fly ash and magnesite.

[0012] Furthermore, the water reducing agent is a polycarboxylic acid high-performance water reducing agent, the water reducing rate is not less than 25%, and the added amount is 0.4-1.2% of the mass of the dry mortar material.

[0013] Furthermore, the shrinkage reducing agent is an amino alcohol shrinkage reducing agent, the shrinkage reduction rate in 28 days exceeds 20%, and the added amount is 0.5-1.5% of the mass of the dry mortar material.

[0014] Furthermore, the fiber is one or more of polyethylene fiber, polyvinyl alcohol fiber and waste carbon fiber.

[0015] Furthermore, the single length of the polyethylene fiber and the polyvinyl alcohol fiber is 10 to 50 mm, and the diameter is 10 to 50 μm; the waste carbon fiber is waste fiber such as aircraft or wind turbine blades, which is heat treated in N2 atmosphere at 400 to 500°C for 30 minutes, cooled to room temperature, and crushed to a length of 10 to 50 mm.

[0016] Furthermore, the specific surface area of ​​the industrial solid waste gypsum is ≥500m 2 / kg, obtained by mixing phosphogypsum or desulfurized gypsum in any proportion and then drying and grinding.

[0017] Furthermore, the high alumina cement is a CA-80 type aluminate cement that meets the technical requirements of GBT201-2015, and its specific surface area is not less than 300m 2 / kg.

[0018] Furthermore, the light-burned magnesium oxide is obtained by calcining magnesite at 950-1050° C., and the MgO content is not less than 90%.

[0019] Furthermore, the rubber powder is vulcanized rubber powder, which complies with GB / T 19208-2020.

[0020] Furthermore, the maximum particle size of the artificial fine sand is not more than 325 μm, and the apparent density is not less than 2700 m 2 / kg.

[0021] The present invention also proposes a method for preparing the multi-element high-salt solid waste alkali salt high-toughness mortar material, comprising the following steps:

[0022] The fly ash and magnesite are mixed and ball-milled to obtain a solid waste mixture, aluminum dihydrogen phosphate, phosphogypsum leachate and water are mixed to prepare a mixed solution, the mixed solution is added to the solid waste mixture to mix evenly, aged, dried, finely ground and sieved to obtain an aged mixture;

[0023] Adding industrial solid waste gypsum, light-burned magnesium oxide, high-alumina cement, rubber powder and artificial fine sand to the aged mixture for dry powder mixing to obtain a dry powder mortar material;

[0024] Add water, shrinkage reducing agent and water reducing agent to the dry mortar material, stir evenly, then add fiber and continue stirring, pour the mixed mortar material into a mold, compact and shape it, and obtain the multi-component high-salt solid waste alkali salt high-toughness mortar material.

[0025] Furthermore, aluminum dihydrogen phosphate, phosphogypsum leachate and water are mixed, and the pH is adjusted to 2.0-2.5 with phosphoric acid to obtain a mixed solution.

[0026] Furthermore, the stirring time of the dry powder mixing is 30s and the rotation speed is 150r / min.

[0027] Furthermore, the aging time is 24 hours and the drying temperature is 60°C.

[0028] Furthermore, the fibers are added in two times, and the mass ratio of the fibers added in the two times is 1:1.

[0029] Furthermore, the water-cement ratio of the multi-component high-salt solid waste alkali salt high-toughness mortar material is 0.4-0.5, and the formed blocks need to be cured under standard conditions. The standard conditions are usually relative humidity of 90%±5%, temperature of 20℃±5℃, and curing for 28 days to obtain optimal performance.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] (1) The present invention grinds fly ash and magnesite together, adds an acidic phosphate aluminate solution for aging, then adds industrial solid waste gypsum, light-burned magnesium oxide, high-alumina cement, rubber powder, artificial fine sand, etc. to make a dry mortar material, and finally adds water for molding to obtain a solid waste-based alkali salt-stabilized mortar material. The alkali salt high-toughness mortar material proposed by the present invention can start the reaction under acidic conditions, and at the same time utilizes fly ash from the incineration of domestic waste, phosphogypsum and phosphogypsum leachate to produce alkali salt-stabilized hydration products, creatively solving the problem of resource utilization of high-salt solid waste.

[0032] (2) The alkali-salt high-toughness mortar material prepared by the present invention achieves the coordinated development of fast hardening, high strength and high toughness. The 1d compressive strength exceeds 15MPa, the 28d compressive strength exceeds 40MPa, and the ultimate strain capacity reaches 2.8-3.7%. It breaks through the technical bottleneck of low toughness of traditional magnesium oxychloride cement and magnesium oxysulfate cement, and is very suitable for dry and cold environments.

[0033] (3) The alkali-salt high-toughness mortar material prepared by the present invention has a characteristic hydration product, potassium magnesium phosphate and hydrated calcium chloroaluminate, which has a very good curing effect on amphoteric and anionic heavy metals in fly ash, breaking through the technical bottleneck of low curing efficiency and poor durability of traditional silicate cement and chelating agent, greatly reducing the environmental risks in the process of material utilization, and being safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0035] Figure 1 This is a flow chart of a method for preparing an alkali-salt high-toughness mortar material from multi-component high-salt solid waste according to the present invention;

[0036] Figure 2A schematic diagram of the mechanism of hydration and heavy metal solidification of alkali-salt high-toughness mortar material prepared from multi-component high-salt solid waste in the present invention;

[0037] Figure 3 is the compressive strength of the mortar materials at different ages in Examples 1 to 15 and Comparative Examples 1 to 5;

[0038] Figure 4 is the flexural strength of the mortar materials at different ages in Examples 1 to 15 and Comparative Examples 1 to 5;

[0039] Figure 5 is the X-ray diffraction pattern of the mortar material in Example 1 and Example 3;

[0040] Figure 6 It is a scanning electron microscope (SEM) image of the aged product after step S1 in Example 1; wherein (a) is the microscopic morphology of the aged product after step S1 in Example 1 magnified 10,000 times; (b) is the surface distribution map of the Ca element by EDS energy spectrum analysis of the SEM map; (c) is the surface distribution map of the C element by EDS energy spectrum analysis of the SEM map; (d) is the surface distribution map of the Mg element by EDS energy spectrum analysis of the SEM map; (e) is the surface distribution map of the Cl element by EDS energy spectrum analysis of the SEM map;

[0041] Figure 7 is the ultimate tensile strength of the mortar material in Examples 1 to 15 and Comparative Examples 1 to 5 after curing for 28 days;

[0042] Figure 8 is the ultimate tensile strain of the mortar material in Examples 1 to 15 and Comparative Examples 1 to 5 after curing for 28 days;

[0043] Fig. 9 It is the softening coefficient of the mortar material in Examples 1 to 15 and Comparative Examples 1 to 5 after being cured for 28 days and then soaked in water for 28 days. DETAILED DESCRIPTION

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0046] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0047] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0048] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0049] The embodiment of the present invention provides a multi-element high-salt solid waste alkali salt high-toughness mortar material, the raw materials include dry-mixed mortar material, shrinkage reducing agent, water reducing agent and fiber, and the fiber is added in an amount of 1.0-2.0% of the mass of the dry-mixed mortar;

[0050] The dry mortar material includes, by weight: 28-40 parts of aged mixture, 10-15 parts of industrial solid waste gypsum, 5-8 parts of light-burned magnesium oxide, 2-5 parts of high-alumina cement, 3-8 parts of rubber powder, and 30-40 parts of artificial fine sand;

[0051] The aged mixture comprises 50-70 parts of fly ash and 30-50 parts of magnesite by weight, and also comprises aluminum dihydrogen phosphate solution and phosphogypsum leachate.

[0052] In a preferred embodiment of the present invention, the fly ash is grate furnace fly ash, with a potassium content of ≥4wt% and a silicon content of ≤3wt%.

[0053] More specifically, the fly ash used in the embodiment of the present invention is waste incineration fly ash, which comes from the Yichang Municipal Waste Incineration Power Plant, and the magnesite used is purchased from Liaoning Haicheng Oriental Magnesium Company.

[0054] In a preferred embodiment of the present invention, the amount of the aluminum dihydrogen phosphate solution and the phosphogypsum leachate added is 80-100% of the total mass of the fly ash and magnesite. Taking 1000g of fly ash and magnesite as an example, the amount of the aluminum dihydrogen phosphate solution and the phosphogypsum leachate added thereto is 800-1000mL.

[0055] In a preferred embodiment of the present invention, the water reducing agent is a polycarboxylic acid high-performance water reducing agent, the water reducing rate is not less than 25%, and the added amount is 0.4-1.2% of the mass of the dry mortar material.

[0056] More specifically, the polycarboxylic acid high performance water reducer used in the embodiments of the present invention is purchased from Jiangsu Subote New Materials Co., Ltd.

[0057] In a preferred embodiment of the present invention, the shrinkage reducing agent is an amino alcohol shrinkage reducing agent, the shrinkage reduction rate in 28 days exceeds 20%, and the added amount is 0.5-1.5% of the mass of the dry mortar material.

[0058] More specifically, the amino alcohol shrinkage reducing agent used in the embodiments of the present invention is purchased from Jiangsu Subote New Materials Co., Ltd.

[0059] In a preferred embodiment of the present invention, the fiber is one or more of polyethylene fiber, polyvinyl alcohol fiber and waste carbon fiber.

[0060] In a preferred embodiment of the present invention, the single length of the polyethylene fiber and the polyvinyl alcohol fiber is 10 to 50 mm, and the diameter is 10 to 50 μm; the waste carbon fiber is waste fiber such as aircraft or wind turbine blades, which is heat treated in a N2 atmosphere at 400 to 500°C for 30 minutes, cooled to room temperature, and crushed to a length of 10 to 50 mm.

[0061] More specifically, the polyethylene fiber used in the embodiments of the present invention is purchased from Shandong Yita Engineering Materials Co., Ltd., the polyvinyl alcohol fiber is purchased from Shanghai Kaiyuan Chemical, and the source of the waste carbon fiber is the discarded wing of a domestic aircraft, which is heat treated at 400°C in N2 atmosphere for 30 minutes, cooled to room temperature, and crushed to a length of 10 to 50 mm.

[0062] In a preferred embodiment of the present invention, the specific surface area of ​​the industrial solid waste gypsum is ≥500m 2 / kg, obtained by mixing, drying and grinding phosphogypsum or desulfurized gypsum in any proportion.

[0063] More specifically, the phosphogypsum used in the embodiments of the present invention is sourced from the storage yard of Hubei Xinyangfeng Fertilizer Co., Ltd., and the desulfurized gypsum is sourced from Yicheng Power Generation Co., Ltd.

[0064] In a preferred embodiment of the present invention, the high alumina cement is a CA-80 aluminate cement that meets the technical requirements of GBT201-2015, and its specific surface area is not less than 300m 2 / kg.

[0065] More specifically, the CA-80 aluminate cement used in the embodiments of the present invention that meets the technical requirements of GBT201-2015 was purchased from Gezhouba Shimen Special Cement Co., Ltd.

[0066] In a preferred embodiment of the present invention, the light-burned magnesium oxide is obtained by calcining magnesite at 950-1050° C., and the MgO content is not less than 90%.

[0067] More specifically, the light-burned magnesium oxide used in the embodiments of the present invention is obtained by calcining magnesite at 950°C.

[0068] In a preferred embodiment of the present invention, the rubber powder is vulcanized rubber powder, which complies with GB / T 19208-2020.

[0069] More specifically, the vulcanized rubber powder used in the embodiments of the present invention was purchased from Hengshui Hongyun Special Recycled Rubber Co., Ltd.

[0070] In a preferred embodiment of the present invention, the maximum particle size of the artificial fine sand is no more than 325 μm, and the apparent density is no less than 2700 m 2 / kg.

[0071] More specifically, the artificial fine sand used in the embodiments of the present invention was purchased from Wuhan Filtration Water Purification Materials Co., Ltd.

[0072] The present invention also proposes a method for preparing the multi-component high-salt solid waste alkali salt high-toughness mortar material, the flow chart of which is shown in Figure 1 , specifically including the following steps:

[0073] The fly ash and magnesite are mixed and ball-milled to obtain a solid waste mixture, aluminum dihydrogen phosphate, phosphogypsum leachate and water are mixed to prepare a mixed solution, the mixed solution is added to the solid waste mixture to mix evenly, aged, dried, finely ground and sieved to obtain an aged mixture;

[0074] Adding industrial solid waste gypsum, light-burned magnesium oxide, high-alumina cement, rubber powder and artificial fine sand to the aged mixture for dry powder mixing to obtain a dry powder mortar material;

[0075] Add water, shrinkage reducing agent and water reducing agent to the dry mortar material, stir evenly, then add fiber and continue stirring, pour the mixed mortar material into a mold, compact and shape it, and obtain the multi-component high-salt solid waste alkali salt high-toughness mortar material.

[0076] In a preferred embodiment of the present invention, aluminum dihydrogen phosphate, phosphogypsum leachate and water are mixed, and the pH is adjusted to 2.0-2.5 with phosphoric acid to obtain a mixed solution.

[0077] In a preferred embodiment of the present invention, the stirring time of the dry powder mixing is 30s and the rotation speed is 150r / min.

[0078] In a preferred embodiment of the present invention, the aging time is 24 hours and the drying temperature is 60°C.

[0079] In a preferred embodiment of the present invention, the fibers are added in two batches, and the mass ratio of the fibers added in the two batches is 1:1.

[0080] In a preferred embodiment of the present invention, the water-cement ratio of the multi-component high-salt solid waste alkali salt high-toughness mortar material is 0.4-0.5, and the formed blocks need to be cured under standard conditions, usually at a relative humidity of 90%±5%, a temperature of 20℃±5℃, and cured for 28 days to obtain optimal performance.

[0081] The schematic diagram of the mechanism of hydration and heavy metal solidification of the multi-component high-salt solid waste alkali salt high-toughness mortar material of the present invention is shown in Figure 2 , specifically:

[0082] The preparation method of the multi-element high-salt solid waste alkali salt high-toughness mortar material of the present invention uses magnesite as the magnesium source during aging, and does not require calcination. Acidic phosphogypsum leachate and aluminum dihydrogen phosphate are used to convert magnesium carbonate (solubility product constant Ksp=-7.46) in magnesite into a highly active soluble magnesium salt, and part of the calcium hydroxychloride in the fly ash is converted into calcium carbonate (solubility product constant Ksp=-8.48) and hydrated calcium chloroaluminate Ca4[Al(OH)6]2Cl2·6H2O (solubility product constant Ksp=-28.28), thereby reducing the soluble chloride content. The reaction equation of this process is as follows:

[0083] 5CaOHCl+MgCO3+2Al(H2PO4)3→Ca4[Al(OH)6]2Cl2·6H2O↓+CaCO3↓+MgCl2+6H3PO4

[0084] The calcium carbonate and hydrated calcium chloroaluminate produced during aging can be used as inert fillers to fill the pores of the alkali salt mortar material and produce highly active soluble magnesium salts. In addition, during aging and drying, CO2 in the air can be captured to promote the production of calcium carbonate.

[0085] In the mortar hydration process, the present invention utilizes the soluble magnesium salt in the aged mixture to generate polyhydroxylated magnesium ions [Mg α (OH) β (H2O) γ ] 2α-β, under the action of chloride and potassium salt in fly ash, sulfate ions in industrial solid waste gypsum and high alumina cement, and phosphate ions in aging mixture, polymerization reaction produces 3MgO·MgCl2·8H2O, 5MgO·MgSO4·7H2O, 2MgKPO4·6H2O alkali salt stable hydration products. The reaction equation of this process is as follows:

[0086]

[0087] The alkali-salt high-toughness mortar material prepared by the present invention forms a tightly packed structure through optimization of the grading of multi-component powder materials, uses lightly burned magnesium oxide and a shrinkage-reducing agent to reduce the volume shrinkage deformation caused by the hydration of alkali-salt stable products, and the fiber plays a toughening role to improve the crack resistance of the mortar material. The introduction of phosphate in phosphogypsum and its leachate can greatly improve the water stability of 3MgO·MgCl2·8H2O and 5MgO·MgSO4·7H2O, and enhance the water resistance of the alkali-salt mortar material; moreover, the active aluminum component in the high-alumina cement is used to further consume free calcium ions and sulfate ions to generate hydrated calcium chloroaluminate Ca4[Al(OH)6]2Cl2·6H2O.

[0088] The alkali salt high-toughness mortar material prepared by the present invention, potassium magnesium phosphate and hydrated calcium chloroaluminate have very good curing effects on amphoteric and anionic heavy metals in fly ash; potassium magnesium phosphate can solidify heavy metals such as Pb, Cu, Zn, Cd, etc. in a weak acid environment, and can even achieve the synergistic curing of Pb and Cu, and calcium chloroaluminate hydrate can solidify heavy metals such as Pb, Cu, Zn, Cd, etc. in a weak acid environment. and Heavy metal oxygen-containing anion groups have excellent curing effect. The reaction equation of this process is as follows:

[0089]

[0090] MgKPO4·6H2O (release phosphate) + Pb 2+ +Cu 2+ →Pb2Cu(PO4)(OH)·3H2O(pH=9-10.5)

[0091]

[0092] The technical solution of the present invention is further illustrated by the following embodiments.

[0093] Example 1

[0094] S1. Take 700g of fly ash and 300g of magnesite and mix them for ball milling to obtain a solid waste mixture, mix 1000mL of 10g / L aluminum dihydrogen phosphate aqueous solution and 1000mL of 10g / L phosphogypsum leachate to prepare a mixed solution, adjust the pH to 2.5 with phosphoric acid, add 1000mL of the mixed solution to the solid waste mixture, mix well, age for 24h, dry at 60°C, and grind and sieve to obtain an aged mixture;

[0095] S2. Take 400 g of the aged mixture obtained in step S1, add 150 g of phosphogypsum, 50 g of light-burned magnesium oxide, 50 g of high-alumina cement, 30 g of rubber powder, and 320 g of artificial fine sand, and mix the mixture at 150 r / min to obtain a dry-mixed mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500 m 2 / kg, light-burned magnesia is type II magnesia that meets the requirements of DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets the requirements of GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0096] S3. Add 400mL of water, 15g of amino alcohol shrinkage reducing agent and 12g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300r / min, add 20g of waste carbon fiber with a single length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time, continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0097] Example 2

[0098] The same as Example 1, except that in step S1, the amount of the mixed solution added to the solid waste mixture is 800 mL.

[0099] Example 3

[0100] The same as Example 1, the only difference is that in step S1, the solid waste mixture contains 500 g of fly ash and 500 g of magnesite.

[0101] Example 4

[0102] The same as Example 1, except that in step S1, when adjusting the pH, phosphoric acid is used to adjust the pH of the mixed solution to 2.0.

[0103] Example 5

[0104] The same as Example 1, the only difference is that in step S2, 150g of phosphogypsum is replaced by desulfurized gypsum.

[0105] Example 6

[0106] The same as Example 1, except that in step S3, the waste carbon fiber is replaced with polyvinyl alcohol fibers with an average length of 18 mm.

[0107] Example 7

[0108] The same as Example 1, except that, in step S3, 500 mL of water, 15 g of amino alcohol shrinkage reducing agent and 12 g of polycarboxylic acid high-performance water reducing agent are added to the prepared dry mortar material (1 kg).

[0109] Example 8

[0110] Step S1 is the same as in Example 1;

[0111] S2. Take 300 g of the aged mixture obtained in step S1, add 100 g of phosphogypsum, 80 g of light-burned magnesium oxide, 50 g of high-alumina cement, 80 g of rubber powder, and 390 g of artificial fine sand thereto for dry powder mixing to obtain a dry powder mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500 m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0112] S3. Add 400mL of water, 15g of amino alcohol shrinkage reducing agent and 4g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 10g of waste carbon fiber with an average root length of 46.3mm, add it in two times, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0113] Example 9

[0114] Step S1 is the same as in Example 1;

[0115] S2. Take 350g of the aged mixture obtained in step S1, add 120g of phosphogypsum, 80g of light-burned magnesium oxide, 20g of high-alumina cement, 30g of rubber powder, and 400g of artificial fine sand to it for dry powder mixing to obtain a dry mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0116] S3. Add 400mL of water, 5g of amino alcohol shrinkage reducing agent and 12g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 20g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0117] Example 10

[0118] Step S1 is the same as in Example 1;

[0119] S2. Take 290 g of the aged mixture obtained in step S1, add 150 g of phosphogypsum, 80 g of light-burned magnesium oxide, 50 g of high-alumina cement, 30 g of rubber powder, and 400 g of artificial fine sand to dry-mix to obtain a dry-mix mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500 m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0120] S3. Add 400mL of water, 15g of amino alcohol shrinkage reducing agent and 4g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 10g of waste carbon fiber with an average root length of 46.3mm, add it in two times, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0121] Embodiment 11

[0122] Step S1 is the same as in Example 1, except that the pH is adjusted to 2.0 with phosphoric acid;

[0123] S2. Take 350g of the aged mixture obtained in step S1, add 100g of phosphogypsum, 50g of light-burned magnesium oxide, 50g of high-alumina cement, 50g of rubber powder, and 400g of artificial fine sand thereto for dry powder mixing to obtain a dry powder mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0124] S3. Add 400mL of water, 5g of amino alcohol shrinkage reducing agent and 4g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 20g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0125] Example 12

[0126] Step S1 is the same as in Example 1, except that the pH is adjusted to 2.0 with phosphoric acid;

[0127] S2. Take 370g of the aged mixture obtained in step S1, add 120g of phosphogypsum, 80g of light-burned magnesium oxide, 50g of high-alumina cement, 80g of rubber powder, and 300g of artificial fine sand thereto for dry powder mixing to obtain a dry powder mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0128] S3. Add 400mL of water, 5g of amino alcohol shrinkage reducing agent and 12g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 10g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0129] Embodiment 13

[0130] Step S1 is the same as in Example 1, except that the pH is adjusted to 2.0 with phosphoric acid;

[0131] S2. Take 350g of the aged mixture obtained in step S1, add 150g of phosphogypsum, 50g of light-burned magnesium oxide, 20g of high-alumina cement, 30g of rubber powder, and 300g of artificial fine sand to dry-mix to obtain a dry-mix mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0132] S3. Add 400mL of water, 15g of amino alcohol shrinkage reducing agent and 12g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 10g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0133] Embodiment 14

[0134] Step S1 is the same as in Example 1, except that the pH is adjusted to 2.0 with phosphoric acid;

[0135] S2. Take 370g of the aged mixture obtained in step S1, add 100g of phosphogypsum, 80g of light-burned magnesium oxide, 20g of high-alumina cement, 80g of rubber powder, and 350g of artificial fine sand thereto for dry powder mixing to obtain a dry powder mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0136] S3. Add 400mL of water, 15g of amino alcohol shrinkage reducing agent and 4g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 20g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0137] Embodiment 15

[0138] Step S1 is the same as in Example 1;

[0139] S2. Take 400 g of the aged mixture obtained in step S1, add 150 g of phosphogypsum, 50 g of light-burned magnesium oxide, 20 g of high-alumina cement, 30 g of rubber powder, and 350 g of artificial fine sand thereto for dry powder mixing to obtain a dry powder mortar material; wherein the specific surface area of ​​the phosphogypsum is ≥500 m 2 / kg, light-burned magnesia is type II magnesia that meets DL / T5296-2014, high-alumina cement is CA-80 aluminate cement that meets the technical requirements of GBT201-2015, rubber powder is 200-mesh vulcanized rubber powder that meets GB / T19208-2020, the maximum particle size of artificial fine sand shall not exceed 325μm, and the apparent density shall not be less than 2730kg / m 3 ;

[0140] S3. Add 400mL of water, 5g of amino alcohol shrinkage reducing agent and 4g of polycarboxylic acid high-performance water reducing agent to the prepared dry mortar material (1kg), stir at a rate of 300 rpm, add 10g of waste carbon fiber with an average root length of 46.3mm, add it twice, add 1 / 2 of the total fiber amount for the first time and continue stirring for 30 seconds, add the remaining fiber material again, stir at the same rate for 90 seconds and then stop to obtain the mortar material, pour the mixed mortar into a mold, compact the material by manual tamping and vibration on a vibration table, and cure it to the corresponding age to obtain the multi-element high-salt solid waste alkali salt high-toughness mortar material.

[0141] Comparative Example 1

[0142] The same as Example 1, except that magnesite is not added, in step S1, 1000 g of fly ash is taken, 1000 mL of 10 g / L aluminum dihydrogen phosphate aqueous solution and 1000 mL of 10 g / L phosphogypsum leachate are mixed to prepare a mixed solution, the pH of which is adjusted to 2.5 with phosphoric acid, 1000 mL of the mixed solution is added to the fly ash, mixed, aged for 24 h, dried at 60° C., and finely ground and sieved to obtain an aged mixture.

[0143] Comparative Example 2

[0144] The same as Example 1, except that, in step S1, 700 g of fly ash and 300 g of magnesite are mixed and ball-milled to obtain a solid waste mixture, 1000 mL of deionized water is added to the solid waste mixture to mix, the mixture is aged for 24 h, dried at 60° C., and finely ground and sieved to obtain an aged mixture.

[0145] Comparative Example 3

[0146] The same as Example 1, except that, in step S2, 550 g of the aged mixture obtained in step S1 is taken, 50 g of light-burned magnesium oxide, 50 g of high-alumina cement, 30 g of rubber powder, and 320 g of artificial fine sand are added thereto for dry powder mixing to obtain a dry powder mortar material.

[0147] Comparative Example 4

[0148] The same as Example 1, except that, in step S2, 450 g of the aged mixture obtained in step S1 is taken, 150 g of phosphogypsum, 50 g of high-alumina cement, 30 g of rubber powder, and 320 g of artificial fine sand are added thereto for dry powder mixing to obtain a dry powder mortar material.

[0149] Comparative Example 5

[0150] The same as Example 1, except that the addition of waste carbon fiber in step S3 is omitted, specifically:

[0151] To the prepared dry mortar material (1 kg), add 400 mL of water, 15 g of amino alcohol shrinkage reducer and 12 g of polycarboxylic acid high-performance water reducer, stir at a rate of 300 rpm, pour the mixed mortar into a mold, and compact the material by manual tamping and vibration on a vibration table. After curing to the corresponding age, a multi-component high-salt solid waste alkali salt high-toughness mortar material can be obtained.

[0152] In order to more clearly reflect the difference in the amount of raw materials used in the examples of the present invention and the comparative examples, the distribution ratios of each group in Examples 1 to 15 of the present invention and Comparative Examples 1 to 5 are shown in Tables 1 to 3:

[0153] Table 1 Allocation ratio of each group in step S1 in Examples 1 to 15 and Comparative Examples 1 to 5

[0154]

[0155]

[0156] Table 2 Allocation ratios of each group in step S2 in Examples 1 to 15 and Comparative Examples 1 to 5

[0157]

[0158] Table 3 Allocation ratios of each group in step S3 in Examples 1 to 15 and Comparative Examples 1 to 5

[0159]

[0160]

[0161] Performance Testing

[0162] According to the relevant provisions of JC / T 2381-2016 "Repair Mortar", the mortar materials prepared in Examples 1 to 15 and Comparative Examples 1 to 5 were tested, and the compressive strength and flexural strength test results of the mortar specimens were shown in Table 1. Figure 3 , Figure 4The alkali-salt high-toughness mortar materials prepared in Examples 1 to 15 of the present invention have higher strength characteristics. Figure 3 It can be seen that under standard curing conditions, the 1d compressive strength can reach 15.1-17.9MPa, and the 28d compressive strength can reach 40.3-46.3MPa. Figure 4 The results show that the 1d flexural strength can reach 6.0~8.5MPa, and the 28d flexural strength can reach 9.3~11.3MPa.

[0163] The X-ray diffraction patterns of Examples 1 and 3 are shown in Figure 5 ,from Figure 5 From the X-ray diffraction patterns of Examples 1 and 3, it can be seen that the mortar materials produced through steps S1 to S3 all produce target mineral phases of potassium magnesium phosphate MgKPO4·6H2O, magnesium oxysulfide 5Mg(OH)2·MgSO4·7H2O, magnesium oxychloride 3Mg(OH)2·MgCl2·8H2O and hydrated calcium chloroaluminate Ca4[Al(OH)6]2Cl2·6H2O and other alkali salt gelled products, and the diffraction peak intensity shows that the products have different contents. The production of calcium carbonate also proves the occurrence of the reaction in step 1.

[0164] Figure 6 The SEM images of the aged product after step S1 in Example 1, wherein (a) is the microscopic morphology of the aged product after step S1 in Example 1 magnified 10,000 times; (b) is the surface distribution spectrum of the Ca element by EDS spectrum analysis of the SEM spectrum; (c) is the surface distribution spectrum of the C element by EDS spectrum analysis of the SEM spectrum; (d) is the surface distribution spectrum of the Mg element by EDS spectrum analysis of the SEM spectrum; (e) is the surface distribution spectrum of the Cl element by EDS spectrum analysis of the SEM spectrum; Figure 6 It can also be seen that calcium carbonate precipitate and a substance whose main elements are Mg and Cl are produced in the aged product of step S1 in Example 1, which can be presumed to be MgCl2, also proving the occurrence of the reaction in step 1.

[0165] According to the relevant provisions of JC / T 2461-2018 "Test Method for Mechanical Properties of High Ductility Fiber Reinforced Cement-based Composite Materials", the mortar materials prepared in Examples 1 to 15 and Comparative Examples 1 to 5 were tested, and the ultimate tensile strength and ultimate tensile strain of the mortar specimens were tested. Figure 7 and Figure 8 It can be seen that the alkali salt high-toughness mortar materials prepared in Examples 1 to 15 of the present invention all have a certain tensile strength. Figure 7 The results show that the 28d ultimate tensile strength is between 3.6 and 4.8 MPa. Figure 8 The results show that the ultimate tensile strain at 28 days is between 2.9% and 3.6%.

[0166] After the mortar specimens cured for 28 days were soaked in running water (1L / min) for 28 days, the surface moisture of the specimens was wiped off, and the compressive strength R28' of the specimens in a wet state was immediately tested. The compressive strength loss of the specimens soaked in water for 28 days was compared with the compressive strength R28 of the specimens under standard curing conditions for 28 days, and the softening coefficient K of the mortar specimens was (R28-R28') / R28. The smaller the K value, the better the water resistance of the specimens. The water resistance results of the alkali-salt high-toughness mortar materials prepared in Examples 1 to 15 of the present invention and Comparative Examples 1 to 5 are shown in Fig. 9 .

[0167] Depend on Fig. 9 It can be seen that the alkali salt high-toughness mortar materials prepared in Examples 1 to 15 of the present invention have the characteristics of good water resistance. After soaking in water for 28 days, the softening coefficient of the specimen is between 4.6% and 8.5%. In Comparative Examples 1 and 2, since the aging step fails to produce effective magnesium chloride, the mortar strength is low and the water penetration resistance is poor; in Comparative Example 3, due to the lack of sulfate in step S2, the magnesium oxysulfide hydration product in the final product is insufficient, and the water resistance is greatly reduced; in Comparative Example 4, due to the lack of light-burned magnesium oxide in step S2, the final alkali salt hydration product is insufficient, resulting in a slight decrease in water resistance; in Comparative Example 5, no fiber is added in step S3, resulting in a significant decrease in the toughness of the mortar material, but it does not affect the formation of alkali salt gelled products, so the compressive strength and water resistance are high, and the ultimate tensile strength is greatly reduced.

[0168] According to the relevant provisions of GB / T 30810-2014 "Determination of leached heavy metals in cement mortar", the leaching concentrations of heavy metals Pb, Cu, Zn, Cr and As in the original fly ash and mortar specimens were tested. The results are shown in Table 4.

[0169] Table 4 Heavy metal leaching concentration (mg / L)

[0170] serial number Pb Cu Zn Cr As Example 1 0.048 0.426 0.277 0.170 0.042 Example 2 0.023 0.570 0.290 0.165 0.045 Example 3 0.055 0.391 0.205 0.089 0.038 Example 4 0.045 0.402 0.110 0.080 0.021 Example 5 0.054 0.434 0.208 0.095 0.039 Example 6 0.041 0.430 0.232 0.102 0.040 Example 7 0.038 0.320 0.190 0.082 0.040 Example 8 0.070 0.416 0.227 0.105 0.041 Example 9 0.034 0.440 0.247 0.109 0.044 Example 10 0.031 0.507 0.261 0.110 0.046 Embodiment 11 0.047 0.490 0.252 0.109 0.043 Example 12 0.029 0.459 0.258 0.117 0.043 Example 13 0.055 0.475 0.246 0.107 0.041 Embodiment 14 0.023 0.425 0.244 0.112 0.041 Embodiment 15 0.042 0.442 0.232 0.111 0.040 Comparative Example 1 0.56 2.88 1.32 29.23 0.44 Comparative Example 2 0.45 3.41 1.54 25.52 0.50 Comparative Example 3 0.24 0.88 0.48 16.88 0.80 Comparative Example 4 0.52 2.41 1.38 31.21 0.85 Comparative Example 5 0.044 0.435 0.236 0.163 0.043 Raw fly ash 1.49 5.19 161.2 44.37 0.87 GB 5085.3-2007 Limits 5 100 100 15 5 GB30760-2024 limit 0.3 1 1 0.2 0.1

[0171] It can be seen from the data in Table 4 that the leaching concentrations of each heavy metal in the mortar materials of Examples 1 to 15 of the present invention and Comparative Example 5 all meet the requirements of the limits of heavy metal content leached from cement clinker in GB / T 30760-2024 "Technical Specifications for Co-treatment of Solid Wastes in Cement Kilns" and the pollution concentration limits in GB 5085.3-2007 "Identification of Hazardous Waste Identification Standards for Leaching Toxicity". The leaching concentrations of heavy metals Pb, Cu, Zn, Cr and As in Comparative Examples 1, 2 and 4 all exceed the requirements of the limits of heavy metal content leached from cement clinker in GB / T 30760-2024 "Technical Specifications for Co-treatment of Solid Wastes in Cement Kilns". In Comparative Example 1, since magnesite was not added in step S1, the fly ash itself would not produce effective soluble magnesium salts, and could not induce the subsequent production of sufficient alkali salt gelling products, and had no obvious curing effect on heavy metals; in Comparative Example 2, since deionized water was added in step S1, the fly ash and magnesite would not react under alkaline conditions to produce effective soluble magnesium salts, and could not induce the subsequent production of sufficient alkali salt gelling products, and had no obvious curing effect on heavy metals; in Comparative Example 3, since industrial solid waste gypsum was not added in step S2, the hydration product accounted for a small proportion in the structure, the mechanical properties of the mortar material decreased, the heavy metal stabilization efficiency decreased, and the leaching concentrations of Cr and As exceeded the standard; in Comparative Example 4, since light-burned magnesium oxide was not added in step S2, polyhydroxylated magnesium ions could not be continuously provided, and sufficient alkali salt gelling products could not be produced to stabilize heavy metals, and had no obvious curing effect on heavy metals; in Comparative Example 5, since fiber was not added in step S3, the ultimate tensile strength and other mechanical properties of the final mortar material were insufficient, but since the gelling components were the same as those in Example 1, sufficient alkali salt gelling products were produced to stabilize heavy metals, and the curing effect on heavy metals was good.

[0172] In summary, the multi-element high-salt solid waste alkali salt high-toughness mortar material prepared by the present invention has the characteristics of high strength, good toughness, good heavy metal stability, etc., and can be used in municipal administration, transportation and other fields.

[0173] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A multi-component high-salt solid waste alkali salt high-toughness mortar material, characterized in that: The raw materials include dry-mix mortar material, shrinkage reducing agent, water reducing agent and fiber, wherein the fiber is added in an amount of 1.0 to 2.0% of the mass of the dry-mix mortar material; The dry mortar material includes, by weight: 28-40 parts of aged mixture, 10-15 parts of industrial solid waste gypsum, 5-8 parts of light-burned magnesium oxide, 2-5 parts of high-alumina cement, 3-8 parts of rubber powder, and 30-40 parts of artificial fine sand; The aged mixture comprises 50-70 parts of fly ash and 30-50 parts of magnesite by weight, and also comprises aluminum dihydrogen phosphate solution and phosphogypsum leachate.

2. The multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 1 is characterized in that: The fly ash is grate furnace fly ash, with a potassium content of ≥4wt% and a silicon content of ≤3wt%.

3. The multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 1 is characterized in that: The total addition amount of the aluminum dihydrogen phosphate solution and the phosphogypsum leachate is 80-100% of the total mass of the fly ash and magnesite.

4. The multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 1, characterized in that: The water reducer is a polycarboxylic acid high-performance water reducer, and the addition amount of the water reducer is 0.4-1.2% of the mass of the dry-mix mortar material. The shrinkage reducer is an amino alcohol shrinkage reducer, and the addition amount of the shrinkage reducer is 0.5-1.5% of the mass of the dry-mix mortar material. The fiber is one or more of polyethylene fiber, polyvinyl alcohol fiber and waste carbon fiber.

5. The multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 1, characterized in that: The specific surface area of ​​the industrial solid waste gypsum is ≥500m 2 / kg; The light-burned magnesium oxide is obtained by calcining magnesite at 950-1050°C, and the MgO content is not less than 90%; The specific surface area of ​​the high alumina cement is ≥300m 2 / kg.

6. The multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 1, characterized in that: The rubber powder is vulcanized rubber powder, and the maximum particle size of the artificial fine sand does not exceed 325 μm.

7. A method for preparing a multi-component high-salt solid waste alkali salt high-toughness mortar material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The fly ash and magnesite are mixed and ball-milled to obtain a solid waste mixture, the aluminum dihydrogen phosphate solution and the phosphogypsum leachate are mixed to prepare a mixed solution, the mixed solution is added to the solid waste mixture to mix evenly, aged, dried, finely ground and sieved to obtain an aged mixture; Adding industrial solid waste gypsum, light-burned magnesium oxide, high-alumina cement, rubber powder and artificial fine sand to the aged mixture for dry powder mixing to obtain a dry powder mortar material; Add water, shrinkage reducing agent and water reducing agent to the dry mortar material, stir evenly, then add fiber and continue stirring, pour the mixed mortar material into a mold, compact and shape it, and obtain the multi-component high-salt solid waste alkali salt high-toughness mortar material.

8. The method for preparing multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 7, characterized in that: Aluminum dihydrogen phosphate, phosphogypsum leachate and water are mixed, and the pH is adjusted to 2.0-2.5 with phosphoric acid to obtain a mixed solution.

9. The method for preparing multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 7, characterized in that: The stirring time of the dry powder mixing is 30s and the rotation speed is 150r / min.

10. The method for preparing multi-component high-salt solid waste alkali salt high-toughness mortar material according to claim 7, characterized in that: The fibers are added in two times, and the mass ratio of the fibers added in the two times is 1:1.

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