Gypsum-based self-leveling mortar, preparation method thereof and gypsum-based self-leveling slurry

Abstract

The invention relates to gypsum-based self-leveling mortar, a preparation method thereof and gypsum-based self-leveling slurry. The gypsum-based self-leveling mortar is prepared from the following raw materials in parts by weight: 580 to 850 parts of desulfurized gypsum clinker, 60 to 180 parts of anhydrite, 120 to 400 parts of filler, 0.5 to 2.5 parts of retarder, 1 to 3 parts of water reducing agent, 0.3 to 0.6 part of defoaming agent, 0.1 to 0.3 part of stabilizer and 0 to 0.3 part of water-retaining agent. The self-leveling mortar provided by the invention has good fluidity, mechanical properties, volume stability, heat-conducting property and the like. The gypsum-based self-leveling floor is cheap in base material and stable and good in performance, and a technical basis is provided for later development of large-scale self-leveling mortar.

Description

Technical Field

[0001] The present application relates to but is not limited to the field of building material technology, and specifically to but is not limited to a gypsum-based self-leveling mortar and a preparation method thereof and a gypsum-based self-leveling slurry. Background Art

[0002] Gypsum-based self-leveling mortar, also known as self-leveling gypsum, refers to a gypsum-based self-leveling material for indoor floors that has a certain fluidity in the freshly mixed state and is composed of hemihydrate calcium sulfate (CaSO4·1 / 2H2O) and type II anhydrous calcium sulfate (CaSO4Ⅱ) alone or a mixture of the two as the main cementitious material, and / or aggregates, fillers and admixtures.

[0003] At present, the problems of gypsum-based self-leveling mortar mainly include the following aspects: the water resistance and wear resistance of gypsum-based mortar are poor, and the slurry is neutral or acidic, which is dangerous for rusting iron parts; the chemical gypsum composition is relatively complex, containing many types of impurities, and although the content is small, it will affect its performance; gypsum is easy to absorb water, has a small softening coefficient, and has poor water resistance; the phase composition of building gypsum is difficult to control; the cost of gypsum pretreatment and admixtures is high; the gypsum-based dry-mixed mortar system lacks formation mechanism research. This system belongs to the field of polymer and gypsum-based composite materials. The interaction between polymers, fillers and gypsum to form the final solidified body is a very complex and not fully understood field. Many reaction mechanisms have not been studied because they are too complicated; the basic formula cannot meet the requirements of mass production and large-scale construction. It is urgent to optimize product formulas, stabilize product performance, reduce product costs, meet customer needs, and develop distinctive formulas and product systems.

[0004] Therefore, there is a need for a gypsum-based self-leveling mortar with cost-effectiveness and good stable performance, a preparation method thereof, and a gypsum-based self-leveling slurry including the mortar. Summary of the invention

[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0006] The present application provides a gypsum-based self-leveling mortar prepared by using desulfurized gypsum clinker and anhydrite, wherein the gypsum-based self-leveling mortar has excellent fluidity, mechanical properties, thermal conductivity and volume stability. The present application also provides a method for preparing the gypsum-based self-leveling mortar and a slurry including the gypsum-based self-leveling mortar.

[0007] On the one hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar include, by weight, 580-850 parts of desulfurized gypsum clinker, 60-180 parts of hard gypsum, 120-400 parts of filler, 0.5-2.5 parts of retarder, 1-3 parts of water reducer, 0.3-0.6 parts of defoamer, 0.1-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

[0008] In some embodiments provided in the present application, the raw materials of the gypsum-based self-leveling mortar include 600-650 parts of desulfurized gypsum clinker, 100-150 parts of hard gypsum, 200-300 parts of filler, 1-2 parts of retarder, 2-2.5 parts of water reducer, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

[0009] In some embodiments provided in the present application, the raw materials of the gypsum-based self-leveling mortar include 600-650 parts of desulfurized gypsum clinker, 100-150 parts of anhydrite, 200-300 parts of filler, 1-2 parts of retarder, 2-2.5 parts of water reducer, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of stabilizer and 0.2-0.3 parts of water retaining agent.

[0010] In some embodiments provided in the present application, the particle size of the desulfurized gypsum clinker is in the range of 80-100 mesh, and the specific surface area is in the range of 2500-7000cm 2 The particle size of the desulfurized gypsum clinker is within the above range, and the water demand of the self-leveling floor material prepared therefrom is relatively stable and will not increase abruptly, and the adverse effect on the mortar properties (mechanical properties, water resistance) is relatively small.

[0011] In the desulfurized gypsum clinker used in the present application, hemihydrate gypsum (HH) / %≥80.0, dihydrate gypsum (DH) / %≤4.0, anhydrous gypsum (AⅢ) / %≤4.0 (or attached water / %≤1.0).

[0012] In some embodiments provided in the present application, the desulfurized gypsum clinker may be selected from one or both of high-strength gypsum (α-hemihydrate gypsum) and building gypsum (β-hemihydrate gypsum).

[0013] In some embodiments provided in the present application, the desulfurized gypsum clinker may be a combination of high-strength gypsum and building gypsum. Any amount of high-strength gypsum may be added to the building gypsum. As the amount of high-strength gypsum added increases, the mortar manufacturing cost will increase.

[0014] In some embodiments provided in the present application, the desulfurized gypsum clinker may be building gypsum (β-hemihydrate gypsum), and the 2h flexural strength of the building gypsum is ≥2MPa and the 2h compressive strength is ≥5.9MPa.

[0015] In some embodiments provided in the present application, the grade of desulfurized gypsum raw material for preparing desulfurized gypsum clinker is ≥88% in terms of calcium sulfate dihydrate.

[0016] In some embodiments provided in the present application, the hard gypsum is type II anhydrous gypsum with a grade of ≥86% and a pH value of ≤12.

[0017] In some embodiments provided in the present application, the filler is selected from one or more of fly ash, quartz sand, heavy calcium, silica ash and river sand.

[0018] The retarder is selected from one or more of an organic retarder, a high-efficiency retarder, and a modified amino acid salt retarder. For example, the retarder can be a high-efficiency retarder, such as the high-efficiency gypsum-based retarder Retardan P produced by TRICOSAL of Germany, or an organic retarder, such as HyCon R 7200F produced by BASF, or a modified amino acid salt retarder, such as Sika 2000PF or 200PF.

[0019] The water reducer is selected from one or more of pyrimidine resin water reducers and polycarboxylic acid water reducers. For example, the water reducer can be a polycarboxylic acid water reducer, such as Melflux5691F and 5581F water reducers produced by BASF, SD600p produced by Sanrui Company, 4100 produced by Jiantubao Company, etc.

[0020] The stabilizer is an anionic polymer viscosity improver, such as anionic polymer viscosity improvers Starvis 3070F and Starvis 3040 produced by BASF.

[0021] The defoaming agent is selected from at least one of a high-carbon alcohol fatty acid ester complex, a polyoxyethylene polyoxyethylene tetraol ether, a polyoxyethylene polyoxypropanolamine ether, a polyoxypropylene glycerol ketone, a polyoxypropylene polyoxyethylene glycerol ether and a polydimethylsiloxane.

[0022] The water retaining agent is selected from one or more of methyl cellulose ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether, and sodium hydroxymethyl cellulose. For example, the water retaining agent can be low-viscosity cellulose, such as hydroxypropyl methyl cellulose, Nouryon BERMOCOLL CCA328; or hydroxyethyl cellulose, Shanghai Huiguang Fine Chemical Co., Ltd. HEC300, etc.

[0023] In some embodiments provided in the present application, the fly ash is Class II fly ash with a particle size of 300-450 mesh; the particle size of the quartz sand is 70-90 mesh or 90-140 mesh.

[0024] In some embodiments provided in the present application, the pH value of the gypsum-based self-leveling mortar is in the range of 10-11.

[0025] In some embodiments provided in the present application, the bulk density of the gypsum-based self-leveling mortar is greater than 1500 kg / m 3 .

[0026] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 580-850 parts of desulfurized gypsum clinker, 60-180 parts of hard gypsum, 120-400 parts of filler, 0.5-2.5 parts of retarder, 1-3 parts of water reducer, 0.3-0.6 parts of defoamer, 0.1-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

[0027] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 600-650 parts of desulfurized gypsum clinker, 100-150 parts of anhydrite, 200-300 parts of filler, 1-2 parts of retarder, 2-2.5 parts of water reducer, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

[0028] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 600-650 parts of desulfurized gypsum clinker, 100-150 parts of hard gypsum, 200-300 parts of filler, 1-2 parts of retarder, 2-2.5 parts of water reducer, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of stabilizer and 0.2-0.3 parts of water retaining agent.

[0029] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 600 parts of desulfurized gypsum clinker, 100 parts of hard gypsum, 200 parts of river sand, 50 parts of heavy calcium, 50 parts of fly ash, 2 parts of retarder, 2 parts of water reducer, 0.5 parts of defoamer, 0.3 parts of stabilizer and 0.3 parts of water retaining agent.

[0030] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 650 parts of desulfurized gypsum clinker, 150 parts of hard gypsum, 200 parts of river sand, 2 parts of retarder, 2 parts of water reducer, 0.5 parts of defoamer, 0.3 parts of stabilizer and 0.3 parts of water retaining agent.

[0031] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 650 parts of desulfurized gypsum clinker, 150 parts of hard gypsum, 200 parts of river sand, 1 part of retarder, 2.5 parts of water reducer, 0.5 parts of defoamer and 0.3 parts of stabilizer.

[0032] On the other hand, the present application provides a gypsum-based self-leveling mortar. The raw materials of the gypsum-based self-leveling mortar are composed, by weight, of 650 parts of desulfurized gypsum clinker, 150 parts of hard gypsum, 150 parts of river sand, 50 parts of fly ash, 2 parts of retarder, 2 parts of water reducer, 0.5 parts of defoamer, 0.3 parts of stabilizer and 0.3 parts of water retaining agent.

[0033] The functional premixed self-leveling mortar produced using desulfurization gypsum waste residue provided in the present application has excellent properties such as good fluidity, high strength, small shrinkage, good alkali resistance, green and environmentally friendly, pollution-free, and resistance to low-temperature drying, opening up a new path for the resource utilization of desulfurization gypsum waste residue.

[0034] On the other hand, the present application provides a method for preparing the gypsum-based self-leveling mortar as described above, comprising the following steps:

[0035] Weigh each component;

[0036] uniformly mixing a retarder, a water reducing agent, a defoamer, a stabilizer and an optional water retaining agent to obtain a premixed powder 1;

[0037] Uniformly mixing premixed powder 1 and filler to obtain premixed powder 2;

[0038] Uniformly mixing desulfurized gypsum clinker and anhydrite to obtain premixed powder 3;

[0039] The premixed powder 2 and the premixed powder 3 are uniformly mixed to obtain the gypsum-based self-leveling mortar.

[0040] In yet another aspect, the present application provides a gypsum-based self-leveling slurry, comprising the gypsum-based self-leveling mortar as described above.

[0041] In some embodiments provided in the present application, the gypsum-based self-leveling slurry may further include mixing water or mixing water plus some admixtures. In some embodiments, the amount of mixing water added may be determined based on the standard consistency water amount, or may be added based on the standard consistency water amount according to specific engineering requirements, which is not limited here.

[0042] Compared with the existing self-leveling mortar, the gypsum-based self-leveling mortar of the present application or the gypsum-based self-leveling slurry prepared by adding water thereto has the following advantages:

[0043] (1) The self-leveling mortar prepared in the present application has good volume stability and small dimensional change rate;

[0044] (2) The desulfurized gypsum used in the present application may be secondary flue gas desulfurized gypsum, and the prepared desulfurized gypsum clinker may be secondary building gypsum. The present application successfully prepared self-leveling mortar with good performance indicators by using high-quality desulfurized building gypsum;

[0045] (3) The self-leveling mortar prepared in this application has good fluidity;

[0046] (4) The self-leveling mortar prepared in the present application can be graded by using raw materials of appropriate mesh sizes so that the volume density of the final self-leveling mortar is as high as at least 1500 kg / m 3 , is an ideal material as floor material;

[0047] (5) The present application effectively reduces the factors that cause the loss of mechanical strength of the mortar material itself by taking measures such as reasonable particle grading of the main components of the raw materials, selection of admixtures, and control of the pH value of the system, so that self-leveling mortar with good mechanical performance indicators can be prepared using secondary building gypsum;

[0048] (6) The gypsum-based self-leveling mortar prepared in this application has a good thermal conductivity (0.71-0.76w / m·K), and is a good material for floor insulation and sound insulation systems with heating;

[0049] (7) The gypsum-based self-leveling mortar prepared in the present application adjusts the pH value of the mortar system (10-11), thereby solving the problem that conventional gypsum-based self-leveling mortar is neutral or acidic, which poses a risk of rusting iron parts;

[0050] (8) The base material used in this application can be building gypsum and anhydrite. The base material is cheap, the prepared mortar has excellent performance, and it is easy to achieve large-scale production and application in the later stage;

[0051] (9) The desulfurized gypsum used in the present application may be low-quality desulfurized gypsum, thereby realizing a new approach to high value-added resource utilization of low-quality desulfurized gypsum;

[0052] (10) The self-leveling mortar prepared in this application is green, environmentally friendly and pollution-free, has good thermal insulation and sound insulation properties, and is beneficial to building energy conservation;

[0053] (11) The self-leveling mortar prepared in the present application has a temperature regulating function, which can effectively reduce the fluctuation range of indoor temperature and improve the comfort of the living environment.

[0054] In addition, the gypsum-based self-leveling mortar of the present application or the gypsum-based self-leveling slurry prepared by adding water thereto has the following additional advantages:

[0055] (1) The various additives in the gypsum-based self-leveling mortar prepared in the present application have good compatibility and are easy to adjust and control;

[0056] (2) The gypsum-based self-leveling mortar prepared in this application has good pumping capacity and is easy to construct;

[0057] (3) The present application can effectively treat desulfurized gypsum waste residue, realize the resource utilization of desulfurized gypsum, and at the same time reduce the production cost of mortar.

[0058] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0060] Figure 1 This is a surface morphology diagram of the fluidity of the gypsum-based self-leveling mortar of Example 1 of the present application;

[0061] Figure 2 This is a surface morphology diagram of the gypsum-based self-leveling mortar of Example 1 of the present application; and

[0062] Figure 3 The morphology of the test block prepared from the slurry of the gypsum-based self-leveling mortar of Example 4 of the present application. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0064] Unless otherwise specified, the raw materials and reagents used in the following examples and comparative examples are commercially available products.

[0065] The desulfurized gypsum clinker used can be prepared by calcining (105-145° C.), ball milling or other methods of treating the desulfurized gypsum raw material. The grade of the desulfurized gypsum raw material used in the examples and comparative examples of the present application is ≥88% in terms of calcium sulfate dihydrate.

[0066] The river sand used can come from Shaanxi Yongtai Wanfu Industry and Trade Co., Ltd.

[0067] The heavy calcium carbonate used can come from the Qinling Power Plant in Luofu Industrial Park, Huayin City, and pass through a 250-mesh sieve.

[0068] The fly ash filler used can come from the Qinling Power Plant in Luofu Industrial Park, Huayin City.

[0069] The retarder used can be a high-efficiency gypsum retarder, such as Sika 2000PF.

[0070] The water reducer used can be a polycarboxylic acid water reducer, 4100 from Jiantubao Company.

[0071] The water-retaining agent used may be Nouryon BERMOCOLL CCA328.

[0072] The stabilizer used may be an anionic polymer viscosity improver produced by BASF, with the brand name Starvis3040.

[0073] The defoaming agent used may be D608 from Jiantubao Company.

[0074] Example 1

[0075] The preparation of gypsum-based self-leveling mortar in this embodiment may include the following steps:

[0076] Step 1: Weigh each component;

[0077] Step 2: uniformly mixing a retarder, a water reducing agent, a defoaming agent, a stabilizer and an optional water retaining agent to obtain a premixed powder 1;

[0078] Step 3: uniformly mixing the premixed powder 1 with heavy calcium, river sand and fly ash to obtain the premixed powder 2;

[0079] Step 4: uniformly mixing the desulfurized gypsum clinker and anhydrite to obtain a premixed powder 3;

[0080] Step 5: uniformly mix the premixed powder 2 and the premixed powder 3 to obtain the gypsum-based self-leveling mortar;

[0081] Example 2

[0082] The difference between Example 2 and Example 1 is that the dosages of heavy calcium, fly ash and water retaining agent are different.

[0083] Example 3

[0084] The difference between Example 3 and Example 1 is that the dosage of heavy calcium is different.

[0085] Example 4

[0086] The difference between Example 4 and Example 1 is that desulfurized gypsum clinker with different mechanical properties is used, and the dosages of heavy calcium, fly ash and water retaining agent are different.

[0087] Example 5

[0088] The difference between Example 5 and Example 4 is that the dosages of the retarder, the water reducing agent and the water retaining agent are different.

[0089] Example 6

[0090] The difference between Example 6 and Example 3 is that desulfurized gypsum clinker with different mechanical properties is used.

[0091] Comparative Example 1

[0092] The raw material composition used in Comparative Example 1 is the same as that in Example 1, and the specific dosage of each component is shown in Table 2.

[0093] Comparative Example 2

[0094] The raw material composition used in Comparative Example 2 is the same as that in Example 1, and the specific dosage of each component is shown in Table 2.

[0095] Comparative Example 3

[0096] The raw material composition used in Comparative Example 3 is basically the same as that in Example 3, but does not include a water retaining agent and a defoaming agent. The specific dosage of each component is shown in Table 2; in addition, the model of the water reducing agent is different, and the water reducing agent used is SD600p from Shanghai Sanrui Company.

[0097] Comparative Example 4

[0098] The raw material composition used in Comparative Example 4 is the same as that in Example 4, and the specific dosage of each component is shown in Table 2.

[0099] Comparative Example 5

[0100] The raw material composition used in Comparative Example 5 is basically the same as that in Example 2, but commercially available 42.5# cement is added. The specific dosage of each component is shown in Table 2.

[0101] The desulfurized gypsum clinker used in the above embodiments and comparative examples may be building gypsum, and the test results of the mechanical properties of the building gypsum may be as described in Table 1:

[0102] Table 1

[0103] Mechanical properties of building gypsum Example 1 Example 4 Example 6 Level 2.0 Level 3.0 2h flexural strength (MPa) 2.3 2.7 3.2 ≥2 ≥3 2h compressive strength (MPa) 6.2 5.9 8.4 ≥4 ≥6

[0104] The dosage (in parts by weight) of each raw material composition in the above-mentioned embodiments and comparative examples is shown in the following Table 2:

[0105] Table 2

[0106]

[0107] In addition, a suitable amount of water (the amount of water added can be determined according to the standard consistency water consumption, which is not limited in this application) can be added to the prepared gypsum-based self-leveling mortar to prepare a gypsum-based self-leveling slurry.

[0108] Performance Testing

[0109] According to the industry standard "Gypsum-based Self-leveling Mortar" (JC / T1023-2021), the performance of the gypsum-based self-leveling mortar prepared in the above embodiment and comparative example was tested, and the test results are shown in Table 3:

[0110] Table 3

[0111]

[0112]

[0113] It can be seen from the results in Table 3 that the present application obtains a self-leveling mortar whose multiple performance indicators including mechanical properties meet the standard "Gypsum-based Self-leveling Mortar" by combining specific components such as desulfurized gypsum clinker, anhydrite, filler, retarder, water reducer, stabilizer, defoamer, etc. in a suitable ratio.

[0114] Depend on Figure 1-Figure 3 It can also be seen that the gypsum-based self-leveling mortar prepared in the embodiment of the present application has good fluidity and is particularly suitable for manufacturing materials such as self-leveling floors. Figure 1 It is shown that the 30-min fluidity of the gypsum-based self-leveling mortar prepared in Example 1 of the present application is 141 mm.

[0115] On the contrary, it can be seen from Comparative Examples 1 to 5 that the self-leveling mortar formed by the specific components with specific proportions not adopted in the present application fails to meet the requirements of the industry standard "Gypsum-based Self-leveling Mortar" in terms of indicators such as 24h flexural strength and 28d absolute dry compressive strength.

[0116] In addition, it can be seen from Comparative Examples 4 and 5 that if the proportion of hard gypsum in the gypsum-based self-leveling mortar system is close to or greater than the proportion of desulfurized gypsum clinker, the pH of the entire slurry system will increase, which will affect the early mechanical properties of the material and cracking will occur at a certain age.

[0117] It can be seen from Comparative Example 5 that since cement is added to the gypsum-based self-leveling mortar system, the pH of the entire material system is increased, affecting the fluidity of the slurry, the 24h flexural strength of the mortar and other mechanical properties, and the material will crack after a certain age. On the contrary, the self-leveling mortar in the embodiment of the present application does not contain cement, which reduces the risk of late cracking of the material. The inventor found that in the early stage of hydration of the material, cement has a certain retarding effect on the system material, but cement itself has a strong hydration reaction activity, and the rapid reaction after encountering water will accelerate the hydration process of desulfurized gypsum clinker, thereby significantly affecting the performance of the mortar mixture. When the cement content in the mortar is high, the time-dependent fluidity loss of the slurry will increase, and it will not have a significant effect on the early strength of the material; although the addition of an appropriate amount of cement can improve the mid-to-late strength of the mortar to a certain extent, the expansion and contraction rates of the system materials are different as the difference between the cement hydration rate and the gypsum hydration rate increases in the later stage, and the risk of cracking of the system materials increases.

[0118] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A gypsum-based self-leveling mortar, characterized in that: In parts by weight, the raw materials of the gypsum-based self-leveling mortar include 580-850 parts of desulfurized gypsum clinker, 60-180 parts of anhydrite, 120-400 parts of filler, 0.5-2.5 parts of retarder, 1-3 parts of water reducer, 0.3-0.6 parts of defoamer, 0.1-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

2. The gypsum-based self-leveling mortar according to claim 1, characterized in that: The raw materials of the gypsum-based self-leveling mortar include 600-650 parts of desulfurized gypsum clinker, 100-150 parts of anhydrite, 200-300 parts of filler, 1-2 parts of retarder, 2-2.5 parts of water reducer, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of stabilizer and 0-0.3 parts of water retaining agent.

3. The gypsum-based self-leveling mortar according to claim 1 or 2, characterized in that: The particle size of the desulfurized gypsum clinker is in the range of 80-100 mesh, and the specific surface area is in the range of 2500-7000cm 2 / g; and / or, the desulfurized gypsum clinker can be selected from one or both of high-strength gypsum and building gypsum.

4. The gypsum-based self-leveling mortar according to claim 3, characterized in that: The desulfurized gypsum clinker is building gypsum, and the 2h flexural strength of the building gypsum is ≥2MPa, and the 2h compressive strength is ≥5.9MPa.

5. The gypsum-based self-leveling mortar according to claim 1 or 2, characterized in that: The anhydrite is type II anhydrous gypsum, with a grade of ≥86% and a pH value of ≤12; and / or, The filler is selected from one or more of fly ash, quartz sand, heavy calcium, silica ash and river sand; and / or, The retarder is selected from one or more of an organic retarder, a high-efficiency retarder, and a modified amino acid salt retarder; and / or, The water reducing agent is selected from one or more of pyrimidine resin-based water reducing agents and polycarboxylic acid-based water reducing agents; and / or, The stabilizer is an anionic polymer viscosity improver; the defoamer is selected from at least one of a high-carbon alcohol fatty acid ester complex, polyoxyethylene polyoxyethylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, polyoxypropylene polyoxyethylene glycerol ether and polydimethylsiloxane; and / or, The water retaining agent is selected from one or more of methyl cellulose ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether and sodium hydroxymethyl cellulose.

6. The gypsum-based self-leveling mortar according to claim 5, characterized in that: The fly ash is Class II fly ash with a particle size of 300-450 meshes; and / or the particle size of the quartz sand is 70-90 meshes or 90-140 meshes.

7. The gypsum-based self-leveling mortar according to claim 1 or 2, characterized in that: The pH of the gypsum-based self-leveling mortar is in the range of 10-11; and / or the bulk density of the gypsum-based self-leveling mortar is greater than 1500 kg / m 3 .

8. A method for preparing a gypsum-based self-leveling mortar according to any one of claims 1 to 7, characterized in that: The steps include: Weigh each component; uniformly mixing a retarder, a water reducing agent, a defoamer, a stabilizer and an optional water retaining agent to obtain a premixed powder 1; uniformly mixing the premixed powder 1 and the filler to obtain the premixed powder 2; Uniformly mixing desulfurized gypsum clinker and anhydrite to obtain premixed powder 3; The premixed powder 2 and the premixed powder 3 are uniformly mixed to obtain the gypsum-based self-leveling mortar.

9. A gypsum-based self-leveling slurry, characterized in that: The invention comprises the gypsum-based self-leveling mortar according to any one of claims 1 to 7.

Images