A kind of dry mortar made of Yellow River sand for sculpture and its preparation process

Abstract

The present invention relates to the technical field of building materials, and particularly relates to a Yellow River sand dry mortar for sculptures and its preparation process. A preparation process of a Yellow River sand dry mortar for sculptures includes the following steps: pretreatment and ultrafine processing of Yellow River sand; hydroxylation, coupling and grafting reaction treatment of fly ash; surface modification of steel slag powder and basalt fiber; preparation of a dihydrate gypsum retarder with desulfurized gypsum; and preparation of the sculpture dry mortar. The present invention uses modified steel slag powder and basalt fiber as admixtures of the mortar, which can improve the strength and durability of the mortar. The surface of the steel slag powder is modified with a copolymer emulsion to reduce the water absorption of the steel slag powder, so that it can delay the setting of cement without cracking due to expansion, and slowly release the adsorbed water in the later stage of the hydration of the binder, promoting the hydration reaction of the binder. The steel slag powder improves the density of the mortar and increases the thickness of the coating surface. The relatively high ultimate elongation and tensile modulus of basalt fiber can inhibit the development of microcracks.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to a dry mortar of Yellow River sand for sculpture and its preparation process. Background Art

[0002] With the continuous development of the construction industry, the types of building materials are also increasing. At the same time, in response to the call for environmental resource utilization, great breakthroughs have been made in the application of Yellow River sand in building materials. Among them, the dry mortar made of Yellow River sand is widely used. For example, in the field of art decoration, with the emergence of sculptures in theme parks, garden landscapes, water parks and campuses, the dry mortar for sculptures has become an important material for landscaping.

[0003] For the application on the sculpture base surface, it is required to be applied evenly and reach a certain thickness, so the process is time-consuming. In the process of applying the existing sculpture mortar, the hydration and setting speed of cement is relatively fast, and the mortar is prone to dry shrinkage and crack, resulting in a decrease in the strength and durability of the mortar base surface. Moreover, the density of the mortar is poor and it is not easy to maintain the required application thickness, thus affecting the forming effect of the sculpture. Therefore, a dry mortar of Yellow River sand for sculpture and its preparation process are needed to solve the above problems. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the purpose of the present invention is to provide a dry mortar of Yellow River sand for sculpture and its preparation process.

[0005] A dry mortar of Yellow River sand for sculpture comprises 30 - 40 parts of portland cement, 58 - 70 parts of superfine Yellow River sand, 17 - 27 parts of grafted fly ash, 1 - 3 parts of modified steel slag powder, 0.07 - 0.09 part of modified basalt fiber, 0.01 - 0.04 part of dihydrate gypsum retarder, 0.01 - 0.05 part of cellulose ether, 0.01 - 0.06 part of redispersible latex powder and 0.3 - 0.5 part of polypropylene fiber.

[0006] A preparation process of a dry mortar of Yellow River sand for sculpture specifically comprises the following steps:

[0007] S1: Pretreatment and ultrafine processing of Yellow River sand

[0008] The Yellow River sand is subjected to ultrasonic impurity removal treatment with absolute ethanol, centrifuged, then subjected to ultrasonic impurity removal treatment with distilled water, centrifuged again, and the product is vacuum dried and then ultrafine processed with a steam kinetic mill to obtain superfine Yellow River sand;

[0009] S2: Hydroxylation, coupling and grafting reaction treatment of fly ash

[0010] The fly ash is subjected to alkali treatment with a sodium hydroxide solution, acid treatment with a sulfuric acid solution after suction filtration and washing with water, coupling reaction with a silane coupling agent after suction filtration and washing with water, centrifugation, washing, and drying, and then graft copolymerization reaction with a graft monomer, followed by centrifugation, washing with water, and drying to obtain grafted fly ash;

[0011] S3: Surface modification of steel slag powder and basalt fiber

[0012] A copolymer emulsion is prepared using styrene and butyl acrylate as monomers, diluted with water, poured into the steel slag powder, stirred evenly, transferred to an oven for curing, taken out and cooled to obtain modified steel slag powder, and the surface of the basalt fiber is treated with a low-temperature plasma treatment device to obtain modified basalt fiber;

[0013] S4: Preparation of a dihydrate gypsum retarder using desulfurized gypsum

[0014] The dry desulfurized gypsum is mixed with water, a catalyst is added, the pH of the solution is adjusted, air is introduced with a blower for catalytic oxidation reaction, the reaction solution is filtered, and the filter cake is taken and dried to obtain the dihydrate gypsum retarder;

[0015] S5: Preparation of sculptural dry-mixed mortar

[0016] Portland cement, ultrafine Yellow River sand, grafted fly ash, modified steel slag powder, modified basalt fiber, dihydrate gypsum retarder, cellulose ether, redispersible latex powder, and polypropylene fiber are added to a mixing pot in a mass ratio of 30 - 40:58 - 70:17 - 27:1 - 3:0.07 - 0.09:0.01 - 0.04:0.01 - 0.05:0.01 - 0.06:0.3 - 0.5, and dry-mixed at 100 - 140 r / min for 2 - 5 min, and then discharged to obtain the sculptural dry-mixed mortar.

[0017] Further, the pretreatment and ultrafine processing of the Yellow River sand in step S1 specifically include the following steps:

[0018] S1.1: Add absolute ethanol to submerge the Yellow River sand, transfer it to an ultrasonic cleaner, perform ultrasonic impurity removal for 20 - 30 min, conduct high-speed centrifugal separation, add distilled water to submerge the solid matter, perform ultrasonic impurity removal for 20 - 30 min, conduct low-speed centrifugal separation, and take the product for vacuum drying to obtain pretreated Yellow River sand;

[0019] S1.2: Open the steam valve of the steam kinetic energy mill, preheat the whole equipment to 90 - 100 °C, pour the pretreated Yellow River sand into the screw feeder, set the steam pressure and temperature to 1 - 1.2 MPa and 250 - 290 °C respectively, set the rotational speed of the classifier to 2000 - 2200 r / min, and conduct ultrafine processing to obtain ultrafine Yellow River sand.

[0020] Further, step S2 performs hydroxylation, coupling, and grafting reactions on fly ash, specifically including the following steps:

[0021] S2.1: Mix 400 - 500 parts by volume of a sodium hydroxide solution with a mass fraction of 22 - 25% and 400 - 500 parts by mass of fly ash, stir and react for 30 - 40 min, perform vacuum filtration, wash the solid with distilled water, add 400 - 500 parts by volume of a dilute sulfuric acid solution with a mass fraction of 10 - 15%, stir and react for 30 - 40 min, perform vacuum filtration, and wash with distilled water to obtain hydroxylated fly ash;

[0022] S2.2: Mix hydroxylated fly ash, silane coupling agent, toluene, and hydroquinone evenly in a ratio of 1:0.5 - 0.8:0.7 - 1:0.009 - 0.015, react at 75 - 85 °C for 4 - 6 h, cool to room temperature, perform low-speed centrifugal separation, wash the product with toluene, and perform vacuum drying to obtain coupled and modified fly ash;

[0023] S2.3: Mix the coupled and modified fly ash and deionized water in a mass ratio of 1:7 - 10, stir and dropwise add 0.5 - 0.8 parts by mass of graft monomer and 0.05 - 0.08 parts by mass of initiator, finish dropping within 1 - 1.5 h, react at 75 - 85 °C for 1 - 2 h, perform low-speed centrifugal separation, wash the product with distilled water, and perform vacuum drying to obtain grafted fly ash.

[0024] Further, the surface modification of steel slag powder and basalt fiber in step S3 specifically includes the following steps:

[0025] S3.1: Stir and mix an emulsifier and deionized water in a mass ratio of 0.02 - 0.03:1, heat up to 80 - 90 °C, add 1 - 3 parts by mass of styrene, stir and emulsify for 10 - 15 min, add 0.01 - 0.02 parts by mass of potassium persulfate, react for 1 - 1.5 h, dropwise add 0.5 - 0.8 parts by mass of butyl acrylate, finish dropping within 0.5 - 1 h, react for 1 - 2 h, and adjust the pH to 7 - 8 with a buffer to obtain a copolymer emulsion;

[0026] S3.2: Mix the copolymer emulsion and deionized water in a mass ratio of 0.7 - 1:1 to obtain a mixed solution. Weigh 250 - 300 parts by mass of steel slag powder, add a mixed solution accounting for 4 - 6% of the mass of the steel slag powder, continuously stir to make the solution evenly distributed on the surface of the steel slag powder, place it in an oven for curing, set the curing temperature to 120 - 150 °C, and the curing time to 1 - 2 h, take it out, and cool to room temperature to obtain modified steel slag powder;

[0027] S3.3: Place the basalt fiber in the vacuum chamber of a low-temperature plasma treatment device, set the discharge power to 220 - 240 W and the discharge gas pressure to 20 - 25 Pa, perform surface pretreatment for 5 - 8 min to obtain modified basalt fiber.

[0028] Further, step S4 uses desulfurized gypsum to prepare a retarder for dihydrate gypsum, which specifically includes the following steps:

[0029] S4.1: Mix dry desulfurized gypsum and water at a mass ratio of 8 - 10:1, add 0.5 - 0.7 parts by mass of ferrous sulfate and 0.4 - 0.6 parts by mass of manganese sulfate, and stir evenly to obtain a slurry;

[0030] S4.2: Transfer the slurry to a reaction flask, adjust the pH of the slurry to 4 - 5 with 1 - 3 mol / L sulfuric acid and 1 - 3 mol / L sodium hydroxide solution, and blow air into the slurry with a blower. Set the air flow rate at 0.15 - 0.25 m 3 / h, and carry out a catalytic oxidation reaction for 1 - 1.5 h;

[0031] S4.3: Filter the reaction solution, take the filter cake and dry it in vacuum at 45 - 60 °C to obtain a retarder for dihydrate gypsum.

[0032] Further, the silane coupling agent in step S2.2 is γ-methacryloxypropyltrimethoxysilane, the grafting monomer in step S2.3 is an aqueous solution of methoxypolyethylene glycol acrylate monomer, and the initiator is a 5 - 10% aqueous solution of ammonium persulfate.

[0033] Further, the emulsifier in step S3.1 is dodecyl diphenyl ether disulfonic acid, and the buffer is sodium bicarbonate.

[0034] Further, the reaction flask in step S4.2 is connected to a buffer flask, the buffer flask is connected to a tail gas absorption flask, and the tail gas absorption flask is filled with a 10 - 20% sodium hydroxide solution by mass fraction.

[0035] Further, 0.5 - 0.7 parts by mass of ferrous sulfate and 0.4 - 0.6 parts by mass of manganese sulfate contained in the filtrate after filtration in step S4.3 are recovered and used to prepare the slurry in step S4.1. Beneficial effects

[0036] 1. The present invention uses modified steel slag powder and basalt fiber as admixtures for mortar, which can improve the strength and durability of mortar. Steel slag powder has high water absorption and certain volume expansion properties. Using copolymer emulsion to modify the surface of steel slag powder can reduce the water absorption of part of the steel slag powder, enabling it to delay the setting of cement without cracking due to expansion. In the later stage of the hydration of the gel material, the steel slag powder can slowly release the adsorbed water, promote the hydration reaction of the binder, reduce the shrinkage of mortar. At the same time, the micro-aggregate effect of the steel slag powder can refine the pore size of the dry mortar, improve the density of the mortar, and make the structure of the mortar system more dense, thereby increasing the thickness of the plastered surface. In addition, basalt fiber has a high ultimate elongation and tensile modulus, which can effectively inhibit the development of microcracks in the mortar matrix, and then improve the strength and durability of the mortar.

[0037] 2. The present invention conducts multiple chemical reaction treatments on fly ash to polymerize polymer macromolecules on the surface of fly ash, enhance the interfacial force, improve the fluidity of fly ash in mortar, and make it evenly dispersed in the slurry. During the hydration process, the modified fly ash will generate gel, which can improve the bonding performance between the aggregate and the binder. Secondly, a colloidal film layer will form on the surface of fly ash during the hardening process, filling the natural defects and microcracks in the hardened mortar, thereby increasing the compressive strength.

[0038] 3. The present invention selects the catalytic oxidation - recrystallization method to prepare the gypsum retarder for hemihydrate gypsum, which can prepare crystals with large and uniform particle sizes and be used as a retarder for mortar, delaying the setting time of cement, reducing the dry shrinkage of cement mortar, reducing the generation of cracks, and helping to improve the strength of the mortar.

[0039] 4. The present invention uses a steam kinetic energy mill to superfine process the Yellow River sand, which can reduce the particle size of the Yellow River sand to play the filling role of ultrafine particles, and can fill the gaps between cements more evenly during the hydration process, thereby improving the density of the mortar and being beneficial to enhancing the overall compressive strength.

[0040] 5. The present invention modifies basalt fiber using plasma, which can increase the surface roughness of basalt fiber, improve the interfacial compatibility between basalt fiber and mortar materials, and is beneficial to the exertion of its performance. Description of the Drawings

[0041] Figure 1 It is a process flow chart of the preparation of the Yellow River sand dry mortar for sculpture adopted in the embodiment of the present invention. Detailed Embodiments

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] Embodiment 1: A preparation process of dry mortar of Yellow River sand for sculpture, as Figure 1 shown, specifically includes the following steps:

[0044] S1: Pretreatment and ultrafine processing of Yellow River sand

[0045] Add absolute ethanol to the Yellow River sand to submerge it, with the surface of the Yellow River sand being submerged by 1 cm. Transfer it to an ultrasonic cleaner, perform ultrasonic impurity removal for 30 min, centrifuge at a high speed of 900 r / min for separation. Add distilled water to submerge the solid matter, perform ultrasonic impurity removal for 30 min, centrifuge at a low speed of 250 r / min for separation. Take the product and vacuum dry it at 60 °C for 18 h to obtain pretreated Yellow River sand;

[0046] Open the steam valve of the steam kinetic mill, preheat the whole equipment to 100 °C, pour the pretreated Yellow River sand into the screw feeder, set the steam pressure and temperature to 1.2 MPa and 290 °C respectively, set the rotation speed of the classifier to 2000 r / min, and perform ultrafine processing to obtain ultrafine Yellow River sand;

[0047] S2: Hydroxylation, coupling and grafting reaction treatment of fly ash

[0048] Mix 450 volume parts of sodium hydroxide solution with a mass fraction of 23% and 450 mass parts of fly ash, stir and react for 40 min, perform vacuum filtration under a negative pressure of 60 kPa, wash the solid matter with distilled water, add 450 volume parts of dilute sulfuric acid solution with a mass fraction of 12%, stir and react for 40 min, perform vacuum filtration under a negative pressure of 60 kPa, and wash with distilled water to obtain hydroxylated fly ash;

[0049] Mix the hydroxylated fly ash, γ-methacryloxypropyltrimethoxysilane, toluene and hydroquinone evenly in a ratio of 1:0.7:0.8:0.012, react at 85 °C for 6 h, cool to room temperature, centrifuge at a low speed of 200 r / min for separation, wash the product with toluene, and vacuum dry at 55 °C to obtain coupled modified fly ash;

[0050] Mix the coupled modified fly ash and deionized water in a mass ratio of 1:9, stir and dropwise add 0.7 mass part of an aqueous solution of polyethylene glycol monomethyl ether acrylate monomer and 0.07 mass part of an aqueous solution of 8% ammonium persulfate, finish dropping within 1.5 h, react at 85 °C for 2 h, centrifuge at a low speed of 150 r / min for separation, wash the product with distilled water, and vacuum dry to obtain grafted fly ash;

[0051] S3: Surface modification of steel slag powder and basalt fiber

[0052] Mix dodecyl diphenyl ether disulfonic acid and deionized water by stirring at a mass ratio of 0.02:1, heat up to 90 °C, add 2 parts by mass of styrene, stir and emulsify for 15 min, add 0.015 parts by mass of potassium persulfate. In the actual operation process, the addition amount of potassium persulfate should not exceed 2% of the mass of styrene as much as possible. React for 1.5 h, dropwise add 0.6 parts by mass of butyl acrylate, finish dropping within 1 h, react for 2 h, adjust the pH to 7 with sodium bicarbonate to obtain a copolymer emulsion;

[0053] Mix the copolymer emulsion and deionized water at a mass ratio of 0.8:1 to obtain a mixed solution. Weigh 280 parts by mass of steel slag powder, add the mixed solution accounting for 5% of the mass of the steel slag powder, continuously stir to make the solution evenly distributed on the surface of the steel slag powder, put it into an oven for curing, set the curing temperature at 150 °C, and the curing time at 2 h. Take it out and cool it at room temperature to obtain modified steel slag powder;

[0054] Place the basalt fiber in the vacuum chamber of a low-temperature plasma treatment device, set the discharge power at 240 W and the discharge gas pressure at 25 Pa, and perform surface pretreatment for 8 min to obtain modified basalt fiber;

[0055] S4: Preparation of dihydrate gypsum retarder with desulfurized gypsum

[0056] Mix dry desulfurized gypsum and water at a mass ratio of 9:1, add 0.6 parts by mass of ferrous sulfate and 0.5 parts by mass of manganese sulfate, and stir evenly to obtain a slurry;

[0057] Transfer the slurry to a reaction flask, adjust the pH of the slurry to 4.5 with 1.5 mol / L sulfuric acid and 1.5 mol / L sodium hydroxide solution, blow air into the slurry with a blower, set the air flow rate at 0.25 m 3 / h, perform catalytic oxidation reaction for 1.5 h. The reaction flask is connected to a buffer flask, and the buffer flask is connected to a tail gas absorption flask. The tail gas absorption flask is filled with 15% sodium hydroxide solution by mass to absorb sulfur dioxide gas generated during the reaction;

[0058] Filter the reaction solution, take the filter cake and dry it in vacuum at 60 °C to obtain the dihydrate gypsum retarder. The filtrate after filtration contains 0.6 parts by mass of ferrous sulfate and 0.5 parts by mass of manganese sulfate. Most of the water is consumed during the catalytic oxidation process and can be ignored. Recover the filtrate for preparing the slurry to recycle ferrous sulfate and manganese sulfate. When preparing, only water and dry desulfurized gypsum need to be proportioned;

[0059] S5: Preparation of sculpture dry mortar

[0060] Add portland cement, ultrafine Yellow River sand, grafted fly ash, modified steel slag powder, modified basalt fiber, dihydrate gypsum retarder, cellulose ether, redispersible latex powder, and polypropylene fiber into a mixing pan according to the mass ratio of 38:60:20:2:0.08:0.03:0.04:0.05:0.4, dry mix for 5 min at 140 r / min, and discharge to obtain the sculpture dry mortar.

[0061] Example 2: A preparation process of Yellow River sand dry mortar for sculpture, as Figure 1 shown, specifically including the following steps:

[0062] S1: Pretreatment and ultrafine processing of Yellow River sand

[0063] Add absolute ethanol to the Yellow River sand to submerge it, with the surface of the Yellow River sand being submerged by 2 cm, transfer it to an ultrasonic cleaner, perform ultrasonic impurity removal for 30 min, centrifuge at a high speed of 900 r / min for separation, add distilled water to submerge the solid matter, perform ultrasonic impurity removal for 30 min, centrifuge at a low speed of 250 r / min for separation, and take the product and dry it in a vacuum at 60 °C for 18 h to obtain the pretreated Yellow River sand;

[0064] Open the steam valve of the steam kinetic energy mill, preheat the whole equipment to 100 °C, pour the pretreated Yellow River sand into the screw feeder, set the steam pressure and temperature to 1.2 MPa and 290 °C respectively, set the rotational speed of the classifier to 2000 r / min, and perform ultrafine processing to obtain ultrafine Yellow River sand;

[0065] S2: Hydroxylation, coupling, and grafting reaction treatment of fly ash

[0066] Mix 500 volume parts of a 25% sodium hydroxide solution by mass with 500 parts by mass of fly ash, stir and react for 40 min, perform vacuum filtration under a negative pressure of 60 kPa, wash the solid matter with distilled water, add 500 volume parts of a 15% dilute sulfuric acid solution by mass, stir and react for 40 min, perform vacuum filtration under a negative pressure of 60 kPa, and wash with distilled water to obtain hydroxylated fly ash;

[0067] Mix hydroxylated fly ash, γ-methacryloxypropyltrimethoxysilane, toluene, and hydroquinone evenly according to the ratio of 1:0.8:1:0.015, react at 85 °C for 6 h, cool to room temperature, centrifuge at a low speed of 200 r / min for separation, wash the product with toluene, and dry it in a vacuum at 55 °C to obtain the coupled and modified fly ash;

[0068] Mix the coupled modified fly ash and deionized water at a mass ratio of 1:10, stir and add dropwise an aqueous solution of 0.8 parts by mass of polyethylene glycol monomethyl ether acrylate monomer and an aqueous solution of 0.08 parts by mass of 10% ammonium persulfate. Finish the addition within 1.5 h, react at 85 °C for 2 h, centrifuge at a low speed of 150 r / min, wash the product with distilled water, and dry it under vacuum to obtain grafted fly ash;

[0069] S3: Surface modification of steel slag powder and basalt fiber

[0070] Stir and mix dodecyl diphenyl ether disulfonic acid and deionized water at a mass ratio of 0.03:1, heat up to 90 °C, add 3 parts by mass of styrene, stir and emulsify for 15 min, add 0.02 parts by mass of potassium persulfate. In the actual operation process, the addition amount of potassium persulfate should not exceed 2% of the mass of styrene as much as possible. React for 1.5 h, add dropwise 0.8 parts by mass of butyl acrylate, finish the addition within 1 h, react for 2 h, and adjust the pH to 8 with sodium bicarbonate to obtain a copolymer emulsion;

[0071] Mix the copolymer emulsion and deionized water at a mass ratio of 1:1 to obtain a mixed solution. Weigh 300 parts by mass of steel slag powder, add the mixed solution accounting for 6% of the mass of the steel slag powder, continuously stir to make the solution evenly distributed on the surface of the steel slag powder, put it into an oven for curing, set the curing temperature at 150 °C and the curing time at 2 h, take it out and cool it at room temperature to obtain modified steel slag powder;

[0072] Place the basalt fiber in the vacuum chamber of a low-temperature plasma treatment device, set the discharge power at 240 W and the discharge gas pressure at 25 Pa, and perform surface pretreatment for 8 min to obtain modified basalt fiber;

[0073] S4: Preparation of a retarder for gypsum dihydrate with desulfurized gypsum

[0074] Mix dry desulfurized gypsum and water at a mass ratio of 10:1, add 0.7 parts by mass of ferrous sulfate and 0.6 parts by mass of manganese sulfate, and stir evenly to obtain a slurry;

[0075] Transfer the slurry to a reaction flask, adjust the pH of the slurry to 5 with 2 mol / L sulfuric acid and 2 mol / L sodium hydroxide solution, blow air into the slurry with a blower, set the air flow rate at 0.25 m 3 / h, and carry out a catalytic oxidation reaction for 1.5 h. The reaction flask is connected to a buffer flask, and the buffer flask is connected to a tail gas absorption flask. The tail gas absorption flask is filled with a 20% sodium hydroxide solution by mass to absorb the sulfur dioxide gas generated during the reaction;

[0076] Filter the reaction solution, take the filter cake and dry it in vacuum at 60 °C to obtain a retarder for gypsum dihydrate. The filtrate after filtration contains 0.7 parts by mass of ferrous sulfate and 0.6 parts by mass of manganese sulfate. Most of the water is consumed during the catalytic oxidation process and can be ignored. The filtrate is recycled for preparing the slurry to recycle ferrous sulfate and manganese sulfate. When preparing, only water and dry-process desulfurized gypsum need to be proportioned.

[0077] S5: Preparation of Sculpture Dry-Mixed Mortar

[0078] Add portland cement, superfine Yellow River sand, grafted fly ash, modified steel slag powder, modified basalt fiber, retarder for gypsum dihydrate, cellulose ether, redispersible latex powder, and polypropylene fiber into the mixing pot according to the mass ratio of 40:70:27:3:0.09:0.04:0.05:0.06:0.5, and dry-mix at 140 r / min for 5 min, then discharge to obtain the sculpture dry-mixed mortar.

[0079] Example 3: A preparation process of Yellow River sand dry-mixed mortar for sculpture, as Figure 1 shown, specifically including the following steps:

[0080] S1: Pretreatment and Ultrafine Processing of Yellow River Sand

[0081] Add absolute ethanol to the Yellow River sand to submerge it, with the surface of the Yellow River sand being submerged by 1 cm, transfer it to an ultrasonic cleaner, perform ultrasonic impurity removal for 25 min, centrifuge at a high speed of 800 r / min for separation, add distilled water to submerge the solid matter, perform ultrasonic impurity removal for 20 min, centrifuge at a low speed of 200 r / min for separation, take the product and dry it in vacuum at 55 °C for 16 h to obtain pretreated Yellow River sand;

[0082] Open the steam valve of the steam kinetic energy mill, preheat the whole equipment to 95 °C, pour the pretreated Yellow River sand into the screw feeder, set the steam pressure and temperature to 1.1 MPa and 260 °C respectively, set the rotational speed of the classifier to 2100 r / min, and perform ultrafine processing to obtain superfine Yellow River sand;

[0083] S2: Hydroxylation, Coupling and Grafting Reaction Treatment of Fly Ash

[0084] Mix 450 volume parts of sodium hydroxide solution with a mass fraction of 23% and 450 parts by mass of fly ash, stir and react for 35 min, perform vacuum filtration under a negative pressure of 55 kPa, wash the solid matter with distilled water, add 450 volume parts of dilute sulfuric acid solution with a mass fraction of 12%, stir and react for 35 min, perform vacuum filtration under a negative pressure of 55 kPa, and wash with distilled water to obtain hydroxylated fly ash;

[0085] Mix hydroxylated fly ash, γ-methacryloxypropyltrimethoxysilane, toluene, and hydroquinone evenly at a ratio of 1:0.7:0.8:0.012, react at 80 °C for 5 h, cool to room temperature, centrifuge at a low speed of 180 r / min for separation, wash the product with toluene, and dry it in vacuum at 50 °C to obtain coupling-modified fly ash;

[0086] Mix the coupling-modified fly ash and deionized water at a mass ratio of 1:9, stir and dropwise add 0.7 parts by mass of an aqueous solution of polyethylene glycol monomethyl ether acrylate monomer and 0.07 parts by mass of an 8% aqueous solution of ammonium persulfate, finish dropping within 1.2 h, react at 80 °C for 1.5 h, centrifuge at a low speed of 120 r / min for separation, wash the product with distilled water, and dry it in vacuum to obtain grafted fly ash;

[0087] S3: Surface modification of steel slag powder and basalt fiber

[0088] Stir and mix dodecyl diphenyl ether disulfonic acid and deionized water at a mass ratio of 0.02:1, heat up to 85 °C, add 2 parts by mass of styrene, stir and emulsify for 12 min, add 0.015 parts by mass of potassium persulfate. In the actual operation process, the addition amount of potassium persulfate should not exceed 2% of the mass of styrene as much as possible. React for 1.2 h, dropwise add 0.6 parts by mass of butyl acrylate, finish dropping within 0.7 h, react for 1.5 h, and adjust the pH to 7 with sodium bicarbonate to obtain a copolymer emulsion;

[0089] Mix the copolymer emulsion and deionized water at a mass ratio of 0.8:1 to obtain a mixed solution. Weigh 280 parts by mass of steel slag powder, add 5% of the mixed solution based on the mass of the steel slag powder, continuously stir to make the solution evenly distributed on the surface of the steel slag powder, put it into an oven for curing, set the curing temperature to 130 °C and the curing time to 1.8 h, take it out, and cool it to room temperature to obtain modified steel slag powder;

[0090] Place the basalt fiber in the vacuum chamber of a low-temperature plasma treatment device, set the discharge power to 220 W and the discharge pressure to 20 Pa, and perform surface pretreatment for 6 min to obtain modified basalt fiber;

[0091] S4: Preparation of a dihydrate gypsum retarder using desulfurized gypsum

[0092] Mix dry desulfurized gypsum and water at a mass ratio of 9:1, add 0.6 parts by mass of ferrous sulfate and 0.5 parts by mass of manganese sulfate, and stir evenly to obtain a slurry;

[0093] Transfer the slurry to a reaction flask, adjust the pH of the slurry to 4.5 with 1.5 mol / L sulfuric acid and 1.5 mol / L sodium hydroxide solution, and blow air into the slurry with a blower. Set the air flow rate to 0.2 m 3React for 1.2 h under catalytic oxidation conditions. The reaction flask is connected to a buffer flask, which is in turn connected to a tail gas absorption flask containing a 15% sodium hydroxide solution by mass to absorb sulfur dioxide gas generated during the reaction;

[0094] Filter the reaction solution, take the filter cake and dry it in vacuum at 55 °C to obtain a gypsum dihydrate retarder. The filtrate after filtration contains 0.6 parts by mass of ferrous sulfate and 0.5 parts by mass of manganese sulfate. Most of the water is consumed during the catalytic oxidation process and can be ignored. Recycle the filtrate for preparing the slurry to recycle ferrous sulfate and manganese sulfate. When preparing, only add water and dry desulfurized gypsum for proportioning;

[0095] S5: Preparation of Sculpture Dry-Mixed Mortar

[0096] Add portland cement, ultra-fine Yellow River sand, grafted fly ash, modified steel slag powder, modified basalt fiber, gypsum dihydrate retarder, cellulose ether, redispersible latex powder, and polypropylene fiber to the mixing pan in a mass ratio of 38:60:20:2:0.08:0.03:0.04:0.05:0.4, and dry mix for 4 min at 125 r / min, then discharge to obtain the sculpture dry-mixed mortar.

[0097] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation process of dry mortar of Yellow River sand for sculpture, characterized in that, Specifically, it includes the following steps: S1: Pretreatment and ultrafine processing of Yellow River sand The Yellow River sand is treated by ultrasonic impurity removal with absolute ethanol, and after centrifugation, it is treated by ultrasonic impurity removal with distilled water. After centrifugation, the product is vacuum dried and then ultrafine processed with a steam kinetic energy mill to obtain ultrafine Yellow River sand; S2: Hydroxylation, coupling and grafting reaction treatment of fly ash The fly ash is treated with a sodium hydroxide solution for alkali treatment. After filtration by suction and washing with water, it is treated with a sulfuric acid solution for acid treatment. After filtration by suction and washing with water, it is subjected to a coupling reaction with γ-methacryloxypropyltrimethoxysilane, centrifuged, washed and dried. The product is subjected to a graft copolymerization reaction with an aqueous solution of polyethylene glycol monomethyl ether acrylate monomer, centrifuged, washed with water and dried to obtain grafted fly ash; S3: Surface modification of steel slag powder and basalt fiber A copolymer emulsion is prepared using styrene and butyl acrylate as monomers, diluted with water, poured into the steel slag powder, stirred and distributed evenly, transferred to an oven for curing, taken out and cooled to obtain modified steel slag powder. The surface of the basalt fiber is treated with a low-temperature plasma treatment device to obtain modified basalt fiber; S4: Preparation of a dihydrate gypsum retarder using desulfurized gypsum The dry desulfurized gypsum is mixed with water, ferrous sulfate and manganese sulfate are added, the pH of the solution is adjusted, air is introduced with a blower for a catalytic oxidation reaction, the reaction solution is filtered, and the filter cake is taken and dried to obtain a dihydrate gypsum retarder; S5: Preparation of sculptural dry-mixed mortar Portland cement, ultrafine Yellow River sand, grafted fly ash, modified steel slag powder, modified basalt fiber, dihydrate gypsum retarder, cellulose ether, redispersible latex powder, and polypropylene fiber are added to a stirring pot according to a mass ratio of 30 - 40:58 - 70:17 - 27:1 - 3:0.07 - 0.09:0.01 - 0.04:0.01 - 0.05:0.01 - 0.06:0.3 - 0.5, and dry mixed at 100 - 140 r / min for 2 - 5 min, and then discharged to obtain sculptural dry-mixed mortar.

2. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 1, characterized in that, For the pretreatment and ultrafine processing of Yellow River sand in step S1, it specifically includes the following steps: S1.1: Add absolute ethanol to submerge the Yellow River sand, transfer it to an ultrasonic cleaner, perform ultrasonic impurity removal for 20 - 30 min, separate by high-speed centrifugation. Add distilled water to submerge the solid matter, perform ultrasonic impurity removal for 20 - 30 min, separate by low-speed centrifugation, and take the product for vacuum drying to obtain pretreated Yellow River sand; S1.2: Open the steam valve of the steam kinetic energy mill, preheat the whole equipment to 90 - 100 °C, pour the pretreated Yellow River sand into the screw feeder, set the steam pressure and temperature to 1 - 1.2 MPa and 250 - 290 °C respectively, set the rotational speed of the classifier to 2000 - 2200 r / min, and perform ultrafine processing to obtain ultrafine Yellow River sand.

3. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 1, characterized in that, For the hydroxylation, coupling and grafting reaction treatment of fly ash in step S2, it specifically includes the following steps: S2.1: Mix 400 - 500 parts by volume of sodium hydroxide solution with a mass fraction of 22 - 25% and 400 - 500 parts by mass of fly ash, stir and react for 30 - 40 min, perform vacuum filtration, wash the solid matter with distilled water, add 400 - 500 parts by volume of dilute sulfuric acid solution with a mass fraction of 10 - 15%, stir and react for 30 - 40 min, perform vacuum filtration, and wash with distilled water to obtain hydroxylated fly ash; S2.2: Mix hydroxylated fly ash, silane coupling agent, toluene, and hydroquinone evenly according to the ratio of 1:0.5 - 0.8:0.7 - 1:0.009 - 0.015, react at 75 - 85 °C for 4 - 6 h, cool to room temperature, perform low-speed centrifugal separation, wash the product with toluene, and dry it under vacuum to obtain coupling-modified fly ash; S2.3: Mix coupling-modified fly ash and deionized water according to a mass ratio of 1:7 - 10, stir and dropwise add 0.5 - 0.8 parts by mass of graft monomer and 0.05 - 0.08 parts by mass of initiator, finish dropping within 1 - 1.5 h, react at 75 - 85 °C for 1 - 2 h, perform low-speed centrifugal separation, wash the product with distilled water, and dry it under vacuum to obtain grafted fly ash.

4. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 1, characterized in that, Step S3: Surface modification of steel slag powder and basalt fiber, specifically including the following steps: S3.1: Stir and mix emulsifier and deionized water according to a mass ratio of 0.02 - 0.03:1, heat up to 80 - 90 °C, add 1 - 3 parts by mass of styrene, stir and emulsify for 10 - 15 min, add 0.01 - 0.02 parts by mass of potassium persulfate, react for 1 - 1.5 h, dropwise add 0.5 - 0.8 parts by mass of butyl acrylate, finish dropping within 0.5 - 1 h, react for 1 - 2 h, and adjust the pH to 7 - 8 with a buffer to obtain copolymer emulsion; S3.2: Mix copolymer emulsion and deionized water according to a mass ratio of 0.7 - 1:1 to obtain a mixed solution. Weigh 250 - 300 parts by mass of steel slag powder, add the mixed solution accounting for 4 - 6% of the mass of the steel slag powder, continuously stir to make the solution evenly distributed on the surface of the steel slag powder, put it into an oven for curing, set the curing temperature at 120 - 150 °C, and the curing time at 1 - 2 h, take it out and cool it to room temperature to obtain modified steel slag powder; S3.3: Place basalt fiber in the vacuum chamber of a low-temperature plasma treatment device, set the discharge power at 220 - 240 W and the discharge gas pressure at 20 - 25 Pa, perform surface pretreatment for 5 - 8 min to obtain modified basalt fiber.

5. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 1, characterized in that, Step S4: Preparation of dihydrate gypsum retarder with desulfurized gypsum, specifically including the following steps: S4.1: Mix dry desulfurized gypsum and water according to a mass ratio of 8 - 10:1, add 0.5 - 0.7 parts by mass of ferrous sulfate and 0.4 - 0.6 parts by mass of manganese sulfate, and stir evenly to obtain a slurry; S4.2: Transfer the slurry to a reaction flask, adjust the pH of the slurry to 4-5 with 1-3 mol / L sulfuric acid and 1-3 mol / L sodium hydroxide solution, and introduce air into the slurry with a blower. Set the air flow rate to 0.15-0.25 m 3 / h, and carry out the catalytic oxidation reaction for 1-1.5 h; S4.3: Filter the reaction solution, take the filter cake and dry it under vacuum at 45 - 60 °C to obtain dihydrate gypsum retarder.

6. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 3, characterized in that, The initiator is 5 - 10% aqueous ammonium persulfate solution.

7. The preparation process of the Yellow River sand dry powder mortar for sculpture according to claim 4, characterized in that, The emulsifier in step S3.1 is dodecyl diphenyl ether disulfonic acid, and the buffer is sodium bicarbonate.

8. The preparation process of a kind of Yellow River sand dry powder mortar for sculpture according to claim 5, characterized in that, The reaction flask in step S4.2 is connected to a buffer flask, and the buffer flask is connected to a tail gas absorption flask. The tail gas absorption flask is filled with a sodium hydroxide solution with a mass fraction of 10-20%.

9. The preparation process of a kind of dry mortar of Yellow River sand for sculpture according to claim 5, characterized in that, Recover 0.5-0.7 parts by mass of ferrous sulfate and 0.4-0.6 parts by mass of manganese sulfate contained in the filtrate after filtration in step S4.3 for preparing the slurry in step S4.

1.

10. A dry mortar made of Yellow River sand for sculpture, characterized in that, It is prepared by the preparation process of the Yellow River sand dry mortar for sculpture according to any one of claims 1-9 above.

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