Preparation method of a gypsum-based mortar material

Abstract

The present invention relates to a preparation method of a gypsum-based mortar material. It is characterized in that, based on the total weight of the gypsum-based mortar material as a percentage benchmark, the mass percentage contents of each component are as follows: gypsum cementitious material 35% - 70%, gypsum sand 25% - 65%, cellulose ether 0.1% - 0.3%, starch ether 0.02% - 0.05%, and sodium sulfate 0.5% - 1%. Compared with the existing solutions, the technical solution of the present invention, by developing a gypsum-based gel material with a specific formula and cooperating with a gypsum sand with a specific formula as the aggregate, enables the finally obtained gypsum-based mortar composition to undergo a ceramization reaction in an alkaline environment due to the presence of a water medium during use, forming an ettringite structure (AFT) and / or calcium silicate hydrate (C-S-H) from the aluminous and siliceous compounds in the raw materials, improving the compactness and water resistance of the mortar solidified paste, and truly having the water resistance characteristic. At the same time, due to the products obtained from the secondary curing reaction during the reaction process, the bonding strength of the mortar is further improved, thus solving the technical problem that the existing gypsum mortar materials cannot simultaneously take into account water resistance and bonding strength.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and particularly to a preparation method of a gypsum-based mortar material. Background Art

[0002] Gypsum-based mortar, mainly composed of gypsum cementitious materials, light or heavy aggregates, and additives, has the advantages of fast hardening and low shrinkage rate compared with cement mortar. However, the defect of poor water resistance has always affected its popularization and application, and furthermore, it has led to a large accumulation of industrial by-product gypsum, resulting in environmental pollution and damage to the ecological environment.

[0003] In recent years, in terms of improving the water resistance of gypsum-based mortar, many scholars have conducted research. CN107056214A discloses a preparation method of a fluorogypsum-based repair mortar. The fluorogypsum-based repair mortar includes 15-80 parts of fluorogypsum, 1-10 parts of active mineral admixture, 20-75 parts of aggregate, 0.5-3 parts of activator, 0.5-3 parts of setting regulator, 0.1-1 part of water reducer, 0.05-0.5 part of water retention and thickening agent, 0.1-1 part of redispersible latex agent, and 0.05-0.5 part of waterproof agent. By forming a dense three-dimensional network of silicate aluminate, the purpose of improving strength and enhancing water resistance is achieved. However, its slurry setting time is relatively fast, and construction must be completed within a short time to achieve the effect, which limits the application site, and its heat preservation and sound insulation effects are poor, and the user experience is difficult to keep up.

[0004] CN106007606A discloses a water-resistant gypsum-based thermal insulation mortar, which uses desulfurized gypsum, mineral powder, cement, alkaline material, cellulose ether, retarder, water reducer, thixotropic agent, polystyrene particles, and water, and achieves high strength and good water resistance through excitation with alkaline excitation materials.

[0005] CN111592319B discloses a water-resistant gypsum mortar and its preparation method. The mortar includes the following components: 15-80 parts of hemihydrate gypsum powder, 10-30 parts of anhydrous gypsum powder, 5-10 parts of cement, 1-10 parts of ground quartz sand, 20-75 parts of silica powder, 0.5-3 parts of bauxite, 0.1-0.3 part of copper sulfate, 0.5-3 parts of sodium lignosulfonate, 0.1-1 part of naphthalene sulfonate formaldehyde condensate, 0.05-0.5 part of ethoxylated alkyl sulfide, 0.1-1 part of fiber, 0.05-0.5 part of sodium methyl silicate, and 50-170 parts of water. The slurry of this technology has an excellent overall configuration. By virtue of good structural density and excellent strength, the water resistance of the slurry is improved, and the energy of sound propagation is effectively consumed and attenuated, and the heat preservation performance of the slurry material is improved.

[0006] CN111777392A discloses a preparation method of water-resistant gypsum mortar. Gypsum powder, vitrified microspheres, cement, retarder, water retention agent, lubricant, stabilizer, air-entraining agent, water reducer, silica, water-repellent agent, slag, steel slag and gypsum whiskers are selected and subjected to the steps of preliminary stirring one, preliminary stirring two, mixing stirring and packaging in sequence to obtain water-resistant gypsum mortar. After the chemical reaction and physical action of silica and water-repellent agent, the strength and water resistance of the gypsum mortar are improved; adding vitrified microspheres can improve the heat preservation and insulation performance of the gypsum mortar, reduce noise transmission and increase the sound insulation effect.

[0007] CN113173770A discloses a high-strength water-resistant gypsum-based mortar and its preparation method, which is composed of the following components: phosphogypsum, titanium gypsum, cement, slag powder, composite filler, composite activator, hydroxypropyl methyl cellulose ether, modified redispersible latex powder, citric acid retarder, polycarboxylate water reducer, water. The initial setting time of the gypsum-based mortar in this technology is ≥243.3 min, the final setting time is ≥368.4 min, the compressive strength (7d) is ≥16.1 MPa, the compressive strength (28d) is ≥23.1 MPa, the softening coefficient is ≥0.98, and the water absorption rate is ≤1.2%. All performances are good, the surface is flat without pitting, and it has a wide application prospect.

[0008] CN115159940A discloses a modified material, gypsum mortar and its preparation method. This modified material includes coated slag, volcanic ash or a mixture of the two; this gypsum mortar uses gypsum, sand, expanded vitrified microspheres, retarder, water retention agent, air-entraining agent, portland cement, polyvinyl alcohol, quicklime and the above-mentioned modified material as raw materials. The mass parts of the above raw materials include: 60-70 parts of gypsum, 10-20 parts of sand, 5-10 parts of expanded vitrified microspheres, 0.5-1 part of retarder, 0.2-0.5 part of water retention agent, 0.02-0.04 part of air-entraining agent, 2-4 parts of portland cement, 5-10 parts of polyvinyl alcohol, 3-5 parts of quicklime and 8-12 parts of modified material. The gypsum mortar in this technology has the advantages of simple preparation process, strong water resistance, low expansion rate, etc. The raw materials used have the advantages of wide sources, low price, industrial solid waste recycling, etc.

[0009] However, in the above several existing technologies, basically the water resistance of the gypsum-based mortar is improved by the chemical reaction of the activator and gypsum, or by introducing a water-repellent agent, and the characteristics of the air-hardening of the gypsum-based cementitious material are not changed. Therefore, the problem of the water resistance of the gypsum-based mortar has not been fundamentally solved. At the same time, the aggregates mentioned in the above patents are mainly sand, and vitrified microspheres are all inert materials, which only play a role of skeleton and filling, and do not further improve the bonding strength.

[0010] Therefore, how to simultaneously solve the water resistance and bonding strength of gypsum-based mortar is a technical problem that needs to be solved urgently. Summary of the invention

[0011] In view of the above defects, the present invention provides a gypsum-based mortar material, which is mainly composed of gypsum gelling material, gypsum sand and functional additives. The composition can effectively solve the water resistance problem of water gypsum-based mortar. At the same time, the gypsum-based gel material and gypsum sand in the formula will undergo secondary curing reaction due to the presence of water medium during use. The product of the curing reaction further improves the bonding strength of the mortar, perfectly solving the problem of balancing the water resistance and bonding strength of the gypsum mortar material. At the same time, a large amount of industrial by-product gypsum is used in the formula of the present invention to achieve the secondary utilization of resources, follow the idea of national resource recycling economy, and more effectively expand the application scenarios of gypsum.

[0012] The invention provides a method for preparing a gypsum-based mortar material, comprising a gypsum-based gel material, gypsum sand, cellulose ether, starch ether and sodium sulfate; based on the total weight of the gypsum-based mortar material, the mass percentage content of each component is: 35% to 70% of gypsum gelling material, 25% to 65% of gypsum sand, 0.1% to 0.3% of cellulose ether, 0.02% to 0.05% of starch ether and 0.5% to 1% of sodium sulfate.

[0013] Furthermore, the preparation method of the gypsum-based gel material comprises:

[0014] Based on the total mass of the raw materials of the gypsum-based gel material, the percentage content of each raw material of the gypsum-based gel material is: gypsum 65%-70%, slag 9.4%-24.8%, lime 2%-5%, mineral powder, 8%-15%, water-soluble sulfate 0.05%-0.15%, water-soluble hydroxide 0.05%-0.2%, silicate 0.05%-0.2%, silicon phosphate 0.02%-0.05%, zeolite 0.2%-2%;

[0015] The preparation method comprises: uniformly mixing gypsum, slag, lime, mineral powder, water-soluble sulfate, water-soluble hydroxide, silicate, silicon phosphate and zeolite according to a certain proportion, grinding the mixture to a particle size of ≤0.037 mm, and preparing a gypsum-based gel material.

[0016] Furthermore, the gypsum is any one of desulfurized gypsum, phosphogypsum, fluorinated gypsum, titanium gypsum or other industrial by-product gypsum, or a combination of any two or more thereof.

[0017] Further, the slag is any one of coal power plant slag and other industrial slags or a combination of any two or more thereof. Further, the mineral powder is any one of powders obtained from fluorite tailings, nickel tailings, iron tailings or other tailings as raw materials or a combination of any two or more thereof.

[0018] Furthermore, the water-soluble sulfate is any one of sodium sulfate, potassium sulfate, zinc sulfate or magnesium sulfate, or a combination of any two or more thereof.

[0019] Furthermore, the water-soluble hydroxide is sodium hydroxide or potassium hydroxide.

[0020] Furthermore, the silicate is any one of sodium silicate, potassium silicate or lithium silicate, or a combination of any two or more thereof.

[0021] Furthermore, the preparation method of the gypsum sand comprises:

[0022] Based on the total mass of the raw materials, the percentage content of the raw materials of the gypsum sand is as follows: parent particles account for 5%-10%, main material 1 accounts for 65%-80%, main material 2 accounts for 10%-15%, auxiliary materials account for 2%-5%, ball-forming materials account for 3%-5%, and the balance is dispersant;

[0023] Mother particle: perlite filter aid with particle size ≤ 0.102mm;

[0024] Main material 1: any one of natural gypsum, desulfurized gypsum, phosphogypsum, fluorinated gypsum, titanium gypsum or other industrial by-product gypsum, or a mixture of any two or more;

[0025] Main material 2: any one of aluminate compounds, silica-alumina minerals, kaolin minerals, dolomite, soluble oxides, aluminum oxide, or a mixture of any two or more thereof;

[0026] Auxiliary materials: any one of active calcium and slaked lime or a mixture of the two;

[0027] Ball forming material: any one of clay, lignin cellulose or bentonite or a mixture of any two or more, with particle size ≤ 0.048mm;

[0028] (1) Grinding: Grind the main material 1, main material 2, auxiliary material and ball-forming material to 0.037±0.005 mm respectively;

[0029] (2) Mud reaction: add the main material 1, main material 2, auxiliary material and ball-forming material into a stirring kettle with an appropriate amount of water and stir them fully at a speed of 50-300r / min for 5-10min. At this time, various materials are fully dispersed in the water to form a mud liquid, and each material can be fully contacted and mixed evenly;

[0030] (3) Dehydration: After the slurry reaction, the slurry is dehydrated by centrifugation, adsorption, and extrusion, and then dried at 150-250° C. to control the water content of the slurry to less than 3% by mass, thereby obtaining a block material;

[0031] (4) Powdering: Grinding the block material into powder of 0.037±0.005 mm by a high-speed grinder at a rotation speed of 3000-6000 r / min;

[0032] (5) Mother ball formation: pour the mother granules into a round pot granulator, spray water through the water spray assembly of the granulator to form particles A, add 1 / 3-1 / 2 of the total weight of the powder to the particles A, and continue to rotate rapidly in the ball mill to form mother balls;

[0033] (6) Sphere formation: The mother ball continues to be sprayed with water mist in the granulator, and the remaining powder is added while spraying. Under the rapid rotation of the ball mill, the mother ball gradually becomes larger to form a first sphere, and no water spraying is required at this point. Then, the dispersant is added to form second spherical particles;

[0034] (7) Sieving: removing the coarse particles from the second spherical particles obtained in step (6) and leaving particles with a mesh size of 40-140 for later use;

[0035] (8) Spheroidizing: The 40-140 mesh particles obtained in step (7) are subjected to a spheroidizing operation again to form a more rounded sphere, wherein the sphericity of the rounded sphere after the shaping operation reaches more than 98%;

[0036] (9) Curing: The round sphere obtained in step (8) is sent to a curing bin for curing, which is carried out in two stages: water spray curing and dry curing;

[0037] (10) The spherical particles obtained in step (9) are sieved to obtain gypsum sand, wherein the gypsum sand has a specification of 0.106 mm-0.425 mm and an internal bulk density of 600 kg / m 3 -1400kg / m 3 . Other indicators meet the requirements of GB / T 14684-2022 "Construction Sand".

[0038] Furthermore, the rotation speed of the ball mill in step 2 is 300-1200 rpm.

[0039] Furthermore, the particle size of the mother ball formed in step 2 is 140-200 mesh.

[0040] Furthermore, in step 3, the speed of the ball mill is 300-1200 rpm. The main material 2 is used as a gypsum reactant. The dispersant is used to solve the problem of sphere dispersion and avoid sphere adhesion.

[0041] Furthermore, in step 3, the particle size of the first sphere is 20-140 mesh.

[0042] Further, in step 4, particles with a particle size ≥ 0.425 mm are removed.

[0043] Further, the curing in step 6 is as follows. Among them, the duration of spraying water mist for curing is 4 - 7 days, each spraying lasts for 4 hours, and it is sprayed once a day. The temperature in the curing chamber is 15 - 25 °C. Then it is transferred to the next curing chamber for dry curing, and the room temperature is maintained for dry curing for 11 - 14 days. The principle of the curing stage is: to cause the gypsum in the raw materials to undergo a ceramization reaction with the gypsum reactant (main material 2) to form ceramic spherical particles. The mass loss rate of the ceramic spherical particles is 5%, meeting the requirements of Class I standard of GB / T 14684 - 2022 "Sand for construction". The softening coefficient is 0.89, having high water resistance, which plays a role in having a high tensile strength when forming tile adhesive later.

[0044] Further, the preparation method of the gypsum mortar composition includes:

[0045] Based on the total mass of the raw materials as a percentage benchmark, the percentage content of the raw materials of the gypsum-based tile adhesive material is: 35% - 70% of the gypsum-based gel material, 25% - 65% of the gypsum sand, 0.1% - 0.3% of the cellulose ether, 0.02% - 0.05% of the starch ether, and 0.5% - 1% of the sodium sulfate.

[0046] Further, the cellulose ether is selected from any one or any combination of two or more of hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, or hydroxypropyl methyl cellulose. The viscosity of the cellulose ether is 10000 - 100000 mPa·s, and the gel temperature is 70 - 90 °C.

[0047] Further, the starch ether is selected from hydroxyalkyl starch, carboxymethyl starch, and cationic starch. The moisture content of the starch ether ≤ 10%, and the viscosity is 400 - 1200 mPa·s.

[0048] Furthermore, during the use of the gypsum mortar composition material, the gypsum-based gel material therein forms a mullite structure and ettringite phase after being mixed and reacted with water, and the plastering gypsum obtained has water resistance. The water resistance is evaluated by the water resistance coefficient under standard curing conditions and flowing water curing conditions. The specific test method is as follows: The gypsum mortar is molded in a 20mm×20mm×20mm mold, cured in a standard curing box for 48h and then demolded. After demolding, the mass of each test block is accurately measured with an analytical balance and recorded as m1. Then, it is soaked and cured in a sealed bottle containing 500mL of distilled water at 20°C. At 7d, 14d, 21d, 28d, 56d, and 98d, the test blocks are taken out, vacuum filtered for 4h, and then the mass m2 is measured. Then, the test blocks are divided into two groups, one group is cured in static water, and the other group is cured in flowing water. The mass m3 of the two groups of specimens is measured by vacuum filtration every week. The water resistance of the specimen is judged by the mass change rate before and after each test block, that is, the water resistance coefficient D w to judge the water resistance of the specimen, D w The larger the value, the stronger the water resistance of the gypsum mortar composition. The calculation formula is as follows:

[0049]

[0050] The measured water resistance coefficient at 7d is -0.02%, at 14d is -0.015, at 21d is -0.0175%, at 28d is -0.0180%, at 56d is -0.016%, and at 98d is 0.0185%. As the curing period lengthens, the water resistance becomes better and better. For the existing gypsum-based mortar composition in the prior art, the water resistance coefficient at 98d is -0.02%, and the water resistance is very poor.

[0051] The beneficial effects of the present invention are as follows:

[0052] Compared with the existing solution, the technical solution of the present invention develops a gypsum-based gel material with a specific formula and uses a gypsum sand with a specific formula as the aggregate. During the use of the finally obtained gypsum-based mortar composition, due to the presence of a water medium, the aluminous and siliceous compounds in the raw materials undergo a ceramization reaction in an alkaline environment to form an ettringite structure (AFT) and / or calcium silicate hydrate (C-S-H), improving the compactness and water resistance of the mortar cured paste, and truly having water resistance characteristics. At the same time, due to the products obtained from the secondary curing reaction during the reaction process, the bonding strength of the mortar is further improved, thus solving the technical problem that the existing gypsum mortar materials cannot simultaneously take into account water resistance and bonding strength. Examples

[0053] The following is a detailed description of the invention in combination with examples:

[0054] Embodiment 1 A method for preparing a gypsum-based mortar material, wherein the raw materials of the gypsum-based mortar material include 35% of a gypsum-based gel material, 63.8% of gypsum sand, 0.2% of cellulose ether, 0.05% of starch ether, and 0.95% of sodium sulfate; dry mixing is performed to form the gypsum-based mortar material;

[0055] The preparation method of the gypsum-based gel material comprises:

[0056] Based on the total weight of the raw materials, the percentage content of the raw materials of the gypsum-based gel material is: desulfurized gypsum 70%, power plant blast furnace slag 10.4%, lime 5%, S95 ore powder 12%, potassium sulfate 0.15%, potassium hydroxide 0.2%, potassium silicate 0.2%, silicon phosphate 0.05%, zeolite 2%;

[0057] The preparation method comprises: mixing gypsum, slag, lime, mineral powder, water-soluble sulfate, water-soluble hydroxide, silicate, silicon phosphate and zeolite in proportion, grinding to a particle size of ≤0.037 mm, and preparing a gypsum-based gel material. The gel material reacts with water to form mullite and ettringite phases, has waterproof properties, and has a 28d compressive strength of ≥45MPa and a flexural strength of ≥2.5MPa.

[0058] The preparation method of the gypsum sand comprises:

[0059] Based on the total mass of the raw materials, the percentage content of the raw materials of the gypsum sand is as follows: 8% of the parent particles, 70% of the main material 1, 15% of the main material 2, 2% of the auxiliary materials, 5% of the ball-forming materials, and the rest is a dispersant, and the dispersant is heavy calcium powder;

[0060] Mother particle: particle size ≤ 0.102mm perlite filter aid 8%;

[0061] Main material 1: desulfurized gypsum;

[0062] Main material 2: aluminate cement;

[0063] Auxiliary materials: active calcium;

[0064] Pelletizing material: lignin cellulose, particle size ≤ 0.048mm;

[0065] The preparation method comprises:

[0066] (1) Grinding: Grind the main material 1, main material 2, auxiliary material and ball-forming material to 0.037 mm respectively;

[0067] (2) Mud reaction: add the main material 1, main material 2, auxiliary material, and ball-forming material into a stirring kettle with an appropriate amount of water and stir them fully at a speed of 100 r / min for 7 minutes. At this time, various materials are fully dispersed in the water to form a mud liquid, and each material can be fully contacted and mixed evenly;

[0068] (3) Dehydration: The slurry after the slurry reaction is dehydrated by centrifugation, adsorption, and extrusion, and then dried at 170° C. to control the water content of the slurry to less than 3% by mass to obtain a block material;

[0069] (4) Powdering: Grinding the block material into powder of 0.037 mm by a high-speed grinder at a rotation speed of 3000 r / min;

[0070] (5) Mother ball formation: pour the mother granules into a round pot granulator, spray water through the water spray assembly of the granulator to form particles A, add 1 / 3 of the total weight of the powder to the particles A, and continue to rotate rapidly in the ball mill to form mother balls;

[0071] (6) Sphere formation: The mother ball continues to be sprayed with water mist in the granulator, and the remaining powder is added while spraying. Under the rapid rotation of the ball mill, the mother ball gradually becomes larger to form a first sphere, and no water spraying is required at this point. Then, the dispersant is added to form second spherical particles;

[0072] (7) Sieving: removing particles with a particle size of ≥0.425 mm from the second spherical particles obtained in step (6), and leaving particles with a size of 40-140 mesh for later use;

[0073] (8) Spheroidizing: The 40-140 mesh particles obtained in step (7) are subjected to a spheroidizing operation again to form a more rounded sphere, wherein the sphericity of the rounded sphere after the shaping operation reaches more than 98%;

[0074] (9) Curing: The round sphere obtained in step (8) is sent to a curing bin for curing, which is carried out in two stages: water spray curing and dry curing;

[0075] (10) The spherical particles obtained in step (9) are sieved to obtain gypsum sand, wherein the gypsum sand has a specification of 0.106 mm-0.425 mm and an internal bulk density of 600 kg / m 3 -1400kg / m 3 . Other indicators meet the requirements of GB / T 14684-2022 "Construction Sand".

[0076] The curing in step (9) is as follows. Among them, the duration of spraying water mist for curing is 4 days, each spraying lasts for 4 hours, and it is sprayed once a day. The temperature in the curing chamber is 15 degrees Celsius. Then it is transferred to the next curing chamber for dry curing, and the room temperature is maintained for dry curing for 14 days. The principle of the curing stage is: to make the main material 1 and the main material 2 (the role of which is the gypsum reactant) in the raw materials undergo a ceramization reaction to form ceramic spherical particles, so that the product has high strength and water resistance. The mass loss rate of the ceramic spherical particles is 5% (high strength), meeting the requirements of Class I standard of GB / T 14684-2022 "Sand for Construction". The softening coefficient is 0.89, having high water resistance, which plays a role in having high tensile strength when forming tile adhesive later.

[0077] Example 2 A preparation method of a gypsum-based tile adhesive material. The raw materials of the gypsum-based tile material include 40% of gypsum-based gel material, 58.9% of gypsum sand, 0.2% of cellulose ether, 0.05% of starch ether, and 0.85% of sodium sulfate. They are dry-mixed and blended into a gypsum-based tile adhesive material;

[0078] The preparation method of the gypsum-based gel material includes:

[0079] Based on the total mass of the raw materials as a percentage benchmark, the percentage content of the raw materials of the gypsum-based gel material is: 65% of phosphogypsum, 8.4% of power plant blast furnace slag, 12% of lime, 12% of S95 mineral powder, 0.15% of sodium sulfate, 0.2% of sodium hydroxide, 0.2% of sodium silicate, 0.05% of silicon phosphate, and 2% of zeolite;

[0080] The preparation method includes: mixing phosphogypsum, power plant blast furnace slag, lime, S95 mineral powder, sodium sulfate, sodium hydroxide, sodium silicate, and zeolite evenly according to the proportion, and grinding to a particle size ≤ 0.037mm to prepare a gypsum-based gel material. After this gel material is mixed and reacted with water, it forms mullite and ettringite phases, having waterproof characteristics, with its 28d compressive strength ≥ 45MPa and flexural strength ≥ 2.5MPa.

[0081] The preparation method of the gypsum sand includes:

[0082] Based on the total mass of the raw materials as a percentage benchmark, the percentage content of the raw materials of the gypsum sand is: 5% of matrix particles, 70% of main material 1, 12% of main material 2, 2% of auxiliary material, 5% of ball-forming material, and the balance is a dispersant, and the dispersant is heavy calcium powder;

[0083] Matrix particles: 5% of perlite filter aid with a particle size ≤ 0.102mm;

[0084] Main material 1: Phosphogypsum;

[0085] Main material 2: Dolomite;

[0086] Auxiliary material: Calcium hydroxide;

[0087] Ball forming material: bentonite, particle size ≤ 0.048mm;

[0088] The preparation method comprises:

[0089] (1) Grinding: Grind the main material 1, main material 2, auxiliary material and ball-forming material to 0.037 mm respectively;

[0090] (2) Mud reaction: add the main material 1, main material 2, auxiliary material, and ball-forming material into a stirring kettle with an appropriate amount of water and stir them fully at a speed of 300 r / min for 10 min. At this time, various materials are fully dispersed in the water to form a mud liquid, and each material can be fully contacted and mixed evenly;

[0091] (3) Dehydration: The slurry after the slurry reaction is dehydrated by centrifugation, adsorption, and extrusion, and then dried at 240° C. to control the water content of the slurry to less than 3% by mass to obtain a block material;

[0092] (4) Powdering: Grinding the block material into powder of 0.037 mm by a high-speed grinder at a rotation speed of 4500 r / min;

[0093] (5) Mother ball formation: pour the mother granules into a round pot granulator, spray water through the water spray assembly of the granulator to form particles A, add 1 / 2 of the total weight of the powder to the particles A, and continue to rotate rapidly in the ball mill to form mother balls;

[0094] (6) Sphere formation: The mother ball continues to be sprayed with water mist in the granulator, and the remaining powder is added while spraying. Under the rapid rotation of the ball mill, the mother ball gradually becomes larger to form a first sphere, and no water spraying is required at this point. Then, the dispersant is added to form second spherical particles;

[0095] (7) Sieving: removing particles with a particle size of ≥0.425 mm from the second spherical particles obtained in step (6), and leaving particles with a size of 40-140 mesh for later use;

[0096] (8) Spheroidizing: The 40-140 mesh particles obtained in step (7) are subjected to a spheroidizing operation again to form a more rounded sphere, wherein the sphericity of the rounded sphere after the shaping operation reaches more than 98%;

[0097] (9) Curing: The round sphere obtained in step (8) is sent to a curing bin for curing, which is carried out in two stages: water spray curing and dry curing;

[0098] (10) Screen the spherical particles obtained in step (9) to obtain gypsum sand, and the specifications of the gypsum sand are 0.106 mm - 0.425 mm, and the internal bulk density is 600 kg / m 3 -1400 kg / m 3 , and other indicators all meet the requirements of GB / T 14684-2022 "Sand for Construction".

[0099] The curing in step (9) is as follows. Among them, the duration of spraying water mist for curing is 5 days, each spraying lasts for 4 hours, and it is sprayed once a day, and the temperature in the curing chamber is 25 degrees Celsius; then transfer to the next curing chamber for dry curing, and the room temperature is maintained for dry curing for 12 days; the principle of the curing stage is: make the gypsum in the raw materials react with the gypsum reactant (main material 2) to form ceramic spherical particles through ceramization reaction. The mass loss rate of the ceramic spherical particles is 5% (high strength), meeting the requirements of Class I standard of GB / T 14684-2022 "Sand for Construction". The softening coefficient is 0.89, which has high water resistance and plays a role in having high tensile strength when forming tile adhesive later.

[0100] Example 3 A preparation method of a gypsum-based tile adhesive material. The raw materials of the gypsum-based tile material include 35% of gypsum-based gel material, 63.8% of gypsum sand, 1% of redispersible latex powder, and 0.2% of cellulose ether; dry mix and blend to form a gypsum-based tile adhesive material.

[0101] The preparation method of the gypsum-based gel material includes:

[0102] Based on the total mass of the raw materials as a percentage benchmark, the percentage content of the raw materials of the gypsum-based gel material is: 65% of fluorogypsum, 8.4% of power plant blast furnace slag, 12% of lime, 12% of mineral powder, 0.15% of magnesium sulfate, 0.2% of potassium hydroxide, 0.2% of lithium silicate, 0.05% of silicon phosphate, and 2% of zeolite;

[0103] The preparation method includes: Mix fluorogypsum, power plant blast furnace slag, lime, mineral powder, magnesium sulfate, ferric hydroxide side table, lithium silicate, and zeolite evenly in proportion and grind to a particle size ≤ 0.037 mm to prepare a gypsum-based gel material. After this gel material is mixed and reacted with water, mullite and ettringite phases are formed, which have waterproof characteristics. Its 28-day compressive strength ≥ 45 MPa and flexural strength ≥ 2.5 MPa.

[0104] The preparation method of the gypsum sand includes:

[0105] Based on the total mass of the raw materials as a percentage benchmark, the percentage content of the raw materials of the gypsum sand is: 5% of matrix particles, 70% of main material 1, 12% of main material 2, 5% of auxiliary materials, 5% of ball-forming materials, and the balance is a dispersant, and the dispersant is heavy calcium powder;

[0106] Mother particle: particle size ≤ 0.102mm perlite filter aid 5%;

[0107] Main material 1: phosphogypsum;

[0108] Main material 2: Dolomite;

[0109] Auxiliary materials: calcium hydroxide;

[0110] Ball forming material: bentonite, particle size ≤ 0.048mm;

[0111] The preparation method comprises:

[0112] (1) Grinding: Grind the main material 1, main material 2, auxiliary material and ball-forming material to 0.037 mm respectively;

[0113] (2) Mud reaction: add the main material 1, main material 2, auxiliary material, and ball-forming material into a stirring kettle with an appropriate amount of water and stir them fully at a speed of 300 r / min for 10 min. At this time, various materials are fully dispersed in the water to form a mud liquid, and each material can be fully contacted and mixed evenly;

[0114] (3) Dehydration: The slurry after the slurry reaction is dehydrated by centrifugation, adsorption, and extrusion, and then dried at 240° C. to control the water content of the slurry to less than 3% by mass to obtain a block material;

[0115] (4) Powdering: Grinding the block material into powder of 0.037 mm by a high-speed grinder at a rotation speed of 4500 r / min;

[0116] (5) Mother ball formation: pour the mother granules into a round pot granulator, spray water through the water spray assembly of the granulator to form particles A, add 1 / 2 of the total weight of the powder to the particles A, and continue to rotate rapidly in the ball mill to form mother balls;

[0117] (6) Sphere formation: The mother ball continues to be sprayed with water mist in the granulator, and the remaining powder is added while spraying. Under the rapid rotation of the ball mill, the mother ball gradually becomes larger to form a first sphere, and no water spraying is required at this point. Then, the dispersant is added to form second spherical particles;

[0118] (7) Sieving: removing particles with a particle size of ≥0.425 mm from the second spherical particles obtained in step (6), and leaving particles with a size of 40-140 mesh for later use;

[0119] (8) Spheroidizing: The 40-140 mesh particles obtained in step (7) are subjected to a spheroidizing operation again to form a more rounded sphere, wherein the sphericity of the rounded sphere after the shaping operation reaches more than 98%;

[0120] (9) Curing: Send the smooth spheres obtained in step (8) to the curing chamber for curing, which is carried out in two stages: spraying water mist curing and dry curing;

[0121] (10) Screen the sphere particles obtained in step (9) to obtain gypsum sand, and the specifications of the gypsum sand are 0.106 mm - 0.425 mm, and the internal bulk density is 600 kg / m 3 - 1400 kg / m 3 . All other indicators meet the requirements of GB / T 14684-2022 "Sand for construction".

[0122] The curing in step (9) is as follows. Among them, the spraying water mist curing lasts for 5 days, each spraying lasts for 4 hours, and it is sprayed once a day, and the temperature in the curing chamber is 25 degrees Celsius; then transfer to the next curing chamber for dry curing, and the room temperature is maintained for dry curing for 12 days; the principle of the curing stage is: make the gypsum in the raw material react with the gypsum reaction agent (main material 2) to form ceramic sphere particles through ceramization reaction. The mass loss rate of the ceramic sphere particles is 5% (high strength), meeting the requirements of Class I standard of GB / T 14684-2022 "Sand for construction", and the softening coefficient is 0.89, having high water resistance, which has a high tensile strength effect when forming tile adhesive later.

[0123] Comparative Example 1

[0124] A kind of gypsum-based mortar, the formula is: 60% gypsum component, 25% river sand component, 12% vitrified microspheres, 0.5% animal protein retarder, 2% nano calcium stearate water repellent, 0.5% hydroxyethyl cellulose ether with a viscosity of 20,000 - 40,000,

[0125] Comparative Example 2

[0126] A kind of gypsum-based mortar, the formula is: 56.5% gypsum component, 25% river sand component, 0.5% animal protein retarder, 0.5% bentonite, 1% silicone waterproof agent, 8% polycarboxylic acid, 0.5% hydroxyethyl cellulose ether with a viscosity of 60,000 - 100,000, 8% polyvinyl alcohol.

[0127] The performance comparison is as follows:

[0128] Item Index Example 1 Example 2 Example 3 Comparative Column 1 Comparative Column 2 Compressive Strength ≥2.5 3.2 3.5 3.6 3.3 2.8 Flexural Strength ≥1.0 1.6 1.5 1.5 1.2 1.1 Tensile Adhesion Strength ≥0.3 0.6 0.6 0.5 0.4 0.3 Softening Coefficient ≥0.85 0.9 0.92 0.90 0.70 0.69

[0129] Based on the content of the above table, it can be seen that the sample of the present invention has the following advantages compared with the similar products of the comparative example:

[0130] 1) The gypsum-based tile adhesive of the present invention solves the problem of water resistance of the existing gypsum mortar, and the softening coefficient is more than 0.2 higher than that of the existing technology;

[0131] (2) The utilization rate of industrial waste gypsum in the gypsum-based mortar of the present invention reaches over 85%. The gypsum sand and the gypsum-based gel material cooperate with each other and are jointly utilized, ultimately achieving that the content of the gypsum-based gel material in the overall material is within 40%.

[0132] (3) The gypsum-based mortar of the present invention adopts a new preparation process. The gypsum sand and the gypsum cementitious material are prepared through compatibility design and have good controllability.

[0133] As described above, it is only a preferred embodiment of the present invention and not any other form of limitation to the present invention. Any modification or equivalent change made according to the technical essence of the present invention still falls within the scope claimed by the present invention.

Claims

1. A preparation method of a gypsum-based mortar material, characterized in that Based on the total weight of the gypsum-based mortar material as a percentage benchmark, the mass percentage contents of each component are: gypsum cementitious material 35% - 70%, gypsum sand 25% - 65%, cellulose ether 0.1% - 0.3%, starch ether 0.02% - 0.05%, and mirabilite 0.5% - 1%; Based on the total mass of the raw materials of the gypsum-based gel material as a percentage benchmark, the percentage contents of each raw material of the gypsum-based gel material are: gypsum 65% - 70%, slag 9.4% - 24.8%, lime 2% - 5%, mineral powder 8% - 15%, water-soluble sulfate 0.05% - 0.15%, water-soluble hydroxide 0.05% - 0.2%, silicate 0.05% - 0.2%, phosphosilicate 0.02% - 0.05%, and zeolite 0.2% - 2%; Based on the total mass of the raw materials as a percentage benchmark, the percentage contents of the raw materials of the gypsum sand are: matrix particles account for 5% - 10%, main material 1 accounts for 65% - 80%, main material 2 accounts for 10% - 15%, auxiliary material accounts for 2% - 5%, ball-forming material accounts for 3% - 5%, and the balance is a dispersant; Matrix particles: perlite filter aid with a particle size ≤ 0.102mm; Main material 1: any one or any mixture of two or more of natural gypsum, desulfurized gypsum, phosphogypsum, fluorogypsum, titanium gypsum, or other industrial by-product gypsums; Main material 2: any one or any mixture of two or more of aluminate compounds, aluminosilicate minerals, kaolin minerals, dolomite, soluble oxides, and aluminum oxide; Auxiliary material: any one or a mixture of two of active calcium and slaked lime; Ball-forming material: any one or any mixture of two or more of clay, lignin fiber, or bentonite, with a particle size ≤ 0.048mm.

2. The preparation method according to claim 1, wherein The preparation method of the gypsum-based gel material includes: Mix gypsum, slag, lime, mineral powder, water-soluble sulfate, water-soluble hydroxide, silicate, phosphosilicate, and zeolite evenly in proportion and grind to a particle size ≤ 0.037mm to prepare the gypsum-based gel material.

3. The preparation method according to claim 2, characterized in that, The gypsum is any one or any combination of two or more of desulfurized gypsum, phosphogypsum, fluorogypsum, titanium gypsum, or other industrial by-product gypsums.

4. The preparation method according to claim 2, characterized in that, The slag is any one or any combination of two or more of coal power plant slag or other industrial slags.

5. The preparation method according to claim 2, characterized in that, The mineral powder is any one or any combination of two or more of powders obtained from fluorite tailings, nickel tailings, iron tailings, or other tailings as raw materials.

6. The preparation method according to claim 2, characterized in that, The water-soluble sulfate is any one or any combination of two or more of sodium sulfate, potassium sulfate, zinc sulfate, or magnesium sulfate.

7. The preparation method according to claim 2, wherein The water-soluble hydroxide is sodium hydroxide or potassium hydroxide.

8. The preparation method according to claim 2, characterized in that, The silicate is any one or any combination of two or more of sodium silicate, potassium silicate, or lithium silicate.

9. The preparation method according to claim 1, characterized in that, The preparation method of the gypsum sand includes: (1) Grinding: Grind main material 1, main material 2, auxiliary material, and ball-forming material respectively to 0.037 ± 0.005mm; (2) Mud reaction: add the main material 1, main material 2, auxiliary material and ball-forming material into a stirring kettle with an appropriate amount of water and stir them fully at a speed of 50-300r / min for 5-10min. At this time, various materials are fully dispersed in the water to form a mud liquid, and each material can be fully contacted and mixed evenly; (3) Dehydration: After the slurry reaction, the slurry is dehydrated by centrifugation, adsorption, and extrusion, and then dried at 150-250° C. to control the water content of the slurry to less than 3% by mass, thereby obtaining a block material; (4) Powdering: Grinding the block material into powder of 0.037±0.005 mm by a high-speed grinder at a rotation speed of 3000-6000 r / min; (5) Mother ball formation: pour the mother granules into a round pot granulator, spray water through the water spray assembly of the granulator to form particles A, add 1 / 3-1 / 2 of the total weight of the powder to the particles A, and continue to rotate rapidly in the ball mill to form mother balls; (6) Sphere formation: The mother ball continues to be sprayed with water mist in the granulator, and the remaining powder is added while spraying. Under the rapid rotation of the ball mill, the mother ball gradually becomes larger to form a first sphere, and no water spraying is required at this point. Then, the dispersant is added to form second spherical particles; (7) Sieving: removing the coarse particles from the second spherical particles obtained in step (6) and leaving particles with a mesh size of 40-140 for later use; (8) Spheroidizing: The 40-140 mesh particles obtained in step (7) are subjected to a spheroidizing operation again to form a more rounded sphere, wherein the sphericity of the rounded sphere after the shaping operation reaches more than 98%; (9) Curing: The round sphere obtained in step (8) is sent to a curing bin for curing, which is carried out in two stages: water spray curing and dry curing; (10) The spherical particles obtained in step (9) are sieved to obtain gypsum sand, wherein the gypsum sand has a specification of 0.106 mm-0.425 mm and an internal bulk density of 600 kg / m 3 -1400 kg / m 3 .

10. The preparation method according to claim 9, characterized in that, The preparation method of the gypsum mortar composition comprises: Based on the total mass of raw materials, the raw material percentage content of the gypsum-based tile adhesive material is: 35%-70% of gypsum-based gel material, 25%-65% of gypsum sand, 0.1%-0.3% of cellulose ether, 0.02%-0.05% of starch ether, and 0.5%-1% of sodium sulfate.

11. The preparation method according to claim 10, characterized in that, The cellulose ether is selected from any one of hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose or hydroxypropyl methyl cellulose or a combination of any two thereof. The viscosity of the cellulose ether is 10000-100000 mPa.s and the gel temperature is 70-90°C.

12. The preparation method according to claim 10, wherein The starch ether is selected from hydroxyalkyl starch, carboxymethyl starch and cationic starch. The moisture content of the starch ether is ≤10% and the viscosity is 400-1200 mPa.s.

Images