Phosphogypsum-based self-leveling mortar as well as preparation method and application thereof

Abstract

The invention provides ardealite-based self-leveling mortar and a preparation method and application thereof, and belongs to the field of construction.The ardealite-based self-leveling mortar is prepared from, by mass, 75-90 parts of anhydrite, 5-15 parts of in-situ exciting agent, 5-10 parts of chemical exciting agent, 0.06-0.1 part of defoaming agent, 0.06-0.1 part of stabilizer and 0.2-0.4 part of water reducing agent; wherein the anhydrous gypsum is II type anhydrous gypsum with D90 smaller than or equal to 30 m, the stacking density of the II type anhydrous gypsum is 0.5-1.5 g / cm < 3 >, and the oil absorption value is 40-60 ml / 100 g. The anhydrite is synergistically excited through the in-situ exciting agent and the chemical exciting agent, under the assistance of the auxiliary agent, the breaking strength and compressive strength of the self-leveling mortar can be improved, the initial setting time of the self-leveling mortar is longer than or equal to 2 h, the final setting time of the self-leveling mortar is shorter than or equal to 8 h, and the use standard of the building field is met.

Description

Technical Field

[0001] The invention relates to the technical field of self-leveling mortar, and in particular to a phosphogypsum-based self-leveling mortar and a preparation method and application thereof. Background Art

[0002] Self-leveling mortar includes cement-based self-leveling, self-leveling mortar, and leveling mortar. It is a dry-mixed powder material composed of multiple active ingredients and can be used after mixing with water on site. Self-leveling mortar also includes gypsum-based self-leveling mortar, which is composed of gypsum raw materials mixed with additives. It has good fluidity and stability and is an important development direction for modern building floor construction.

[0003] Commonly used gypsum-based self-leveling mortar needs to meet the requirements of initial setting time ≥ 2h and final setting time ≤ 8h in order to meet the use standards in the construction field. However, under the premise of meeting the above requirements, gypsum-based self-leveling mortar often has the defect of insufficient strength.

[0004] Therefore, it is necessary to provide a gypsum-based self-leveling mortar that can meet the setting time and ensure strength. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present application provides a phosphogypsum-based self-leveling mortar and a preparation method and application thereof, aiming to solve the technical problem of how to achieve a gypsum-based self-leveling mortar that can meet both the setting time and strength.

[0006] In the first aspect, the embodiment of the present application provides a phosphogypsum-based self-leveling mortar, comprising the following components by mass: 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, and 0.2-0.4 parts of water reducer; wherein the anhydrous gypsum is type II anhydrous gypsum with D90≤30µm, and the bulk density of type II anhydrous gypsum is 0.5-1.5g / cm 3 , the oil absorption value is 40-60ml / 100g.

[0007] In the technical solution of the embodiment of the present application, the anhydrous gypsum is synergistically stimulated by an in-situ activator and a chemical activator and with the assistance of an auxiliary agent, the flexural strength and compressive strength of the self-leveling mortar are improved, and the initial setting time is ≥2h, and the final setting time is ≤8h. The flexural strength and compressive strength of the self-leveling mortar are further improved by limiting the parameter performance of the anhydrous gypsum.

[0008] In some embodiments, the in-situ activator includes one or more of hemihydrate gypsum and dihydrate gypsum; and / or the chemical activator includes one or more of acidic activators and alkaline activators.

[0009] In this embodiment, the acidic activator accelerates the dissolution process of anhydrous gypsum by reducing the activation energy required for the dissolution of anhydrous gypsum, and at the same time reduces the potential of the solid-liquid interface of the hydration system through the electrolyte effect, which is beneficial to improving the early strength of the self-leveling mortar and shortening the final setting time; the alkaline activator can promote the acceleration of the hydration reaction of anhydrous gypsum and the generation of new products, so that the strength of the obtained self-leveling mortar is improved, and the water resistance and durability are improved; compared with the acidic activator, the alkaline activator will not have the acid regurgitation phenomenon, and the strength of the self-leveling mortar is improved to a higher degree; the acidic activator, the alkaline activator and the in-situ activator synergistically help promote the hydration and hardening process of anhydrous gypsum and improve the strength of the self-leveling mortar.

[0010] In some embodiments, the hemihydrate gypsum includes one or more of α-gypsum and β-gypsum; and / or the acidic activator includes one or more of potassium sulfate, sodium sulfate, and alum; and / or the alkaline activator includes one or more of cement, steel slag, slag, fly ash, and calcium oxide.

[0011] In this embodiment, the use of α gypsum as an in-situ activator is more conducive to improving the strength of gypsum-based self-leveling mortar, and the use of β gypsum as an in-situ activator can improve the strength of gypsum-based self-leveling mortar with low cost; the acidic activator and alkaline activator of this embodiment are easy to obtain, which is conducive to expanding production.

[0012] In some embodiments, the in-situ activator comprises hemihydrate gypsum and the chemical activator comprises a mixture of calcium oxide and alum; and / or, the in-situ activator comprises hemihydrate gypsum and the chemical activator comprises cement.

[0013] In this embodiment, the semi-hydrated gypsum is compounded with some chemical activators, which is more conducive to improving the strength of the gypsum-based self-leveling mortar, and prolonging the initial setting time and shortening the final setting time.

[0014] In some embodiments, the mass ratio of calcium oxide to alum is 5:(2-3).

[0015] In this embodiment, under a limited ratio, it is beneficial to extend the initial setting time and shorten the final setting time of the gypsum-based self-leveling mortar. However, if the amount of calcium oxide is too much, the initial setting time will be shortened, and if the amount of calcium oxide is too little, it will be not conducive to improving the strength.

[0016] In some embodiments, based on 100 parts of the sum of the masses of the anhydrous gypsum, the chemical activator and the in-situ activator, the mass fraction of the chemical activator is 6-10 parts; and / or, the mass ratio of anhydrous gypsum to the in-situ activator is 9:(0.5-1.5).

[0017] In this embodiment, if the content of the chemical activator or the in-situ activator is too much, the setting time will not meet the requirements, and if the content of the chemical activator or the in-situ activator is too little, the strength of the gypsum-based self-leveling mortar will be reduced.

[0018] In some embodiments, 0.05-0.1 parts by mass of a retarder are also included.

[0019] In this embodiment, the retarder can increase the fluidity of the self-leveling mortar, reduce the generation of bubbles and holes, and help improve the density and strength of the self-leveling mortar.

[0020] In some embodiments, the water reducer includes one or more of a naphthalene water reducer and a polycarboxylic acid water reducer; and / or, the defoamer includes one or more of a silicone defoamer and a high-carbon alcohol defoamer; and / or, the stabilizer includes one or more of hydroxypropyl methylcellulose, sodium bentonite, and sodium polyacrylate; and / or, the retarder includes a protein retarder.

[0021] In this embodiment, the water reducing agent is helpful to reduce the friction between anhydrous gypsum and other components, so as to promote the bonding between the components and improve the strength of the self-leveling mortar. The protein retarder has a relatively mild inhibitory effect on the growth of gypsum crystals, and the growth rate of each crystal face is inhibited at the same time, and the crystal morphology does not change much, so the loss of the strength of the self-leveling mortar is smaller.

[0022] In a second aspect, the present application provides a method for preparing phosphogypsum-based self-leveling mortar, comprising the steps of: Providing a variety of raw materials, and blending the multiple raw materials to obtain a mixed material; Add water to the mixture and stir evenly to obtain phosphogypsum-based self-leveling mortar; Among them, the various raw materials include, by mass, 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, 0.2-0.4 parts of water reducer and / or 0.05-0.1 parts of retarder.

[0023] In this embodiment, before the step of blending the multiple raw materials, there is also a step of drying the multiple raw materials. Blending after drying is beneficial for uniform dispersion and mixing of the raw material components in a dry powder state. Thereafter, when water is added and stirred for hydration, the preparation efficiency of the self-leveling mortar can be improved.

[0024] In a third aspect, the present application provides an application of phosphogypsum-based self-leveling mortar in the construction field.

[0025] In this embodiment, gypsum-based self-leveling mortar is used as a high-strength self-leveling mortar in the construction field. It has high flexural strength and compressive strength, and the initial and final setting times meet the construction requirements, thereby improving the durability and construction convenience of the self-leveling layer.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0027] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above description and any variations thereof are intended to cover non-exclusive inclusions.

[0029] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0032] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0033] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0034] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0035] In the prior art, self-leveling mortar includes gypsum-based self-leveling mortar, which is composed of gypsum raw materials mixed with additives, has good fluidity and stability, high early strength, fast construction speed, low labor intensity, and is an important development direction for modern building floor construction. Commonly used gypsum-based self-leveling mortar needs to meet the requirements of initial setting time ≥ 2h and final setting time ≤ 8h to meet the use standards in the construction field. However, under the premise of meeting the above requirements, gypsum-based self-leveling mortar often has the defect of insufficient strength.

[0036] In order to solve the technical problem of how to achieve gypsum-based self-leveling mortar that can meet both the setting time and ensure the strength, the present application provides a phosphogypsum-based self-leveling mortar and a preparation method and application thereof.

[0037] In the first aspect, the embodiment of the present application provides a phosphogypsum-based self-leveling mortar, comprising the following components by mass: 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, and 0.2-0.4 parts of water reducer; wherein the anhydrous gypsum is type II anhydrous gypsum with D90≤30µm, and the bulk density of type II anhydrous gypsum is 0.5-1.5g / cm 3, the oil absorption value is 40-60ml / 100g.

[0038] In the technical solution of the embodiment of the present application, the anhydrous gypsum is synergistically stimulated by an in-situ activator and a chemical activator and with the assistance of an auxiliary agent, the flexural strength and compressive strength of the self-leveling mortar are improved, and the initial setting time is ≥2h, and the final setting time is ≤8h. The flexural strength and compressive strength of the self-leveling mortar are further improved by limiting the parameter performance of the anhydrous gypsum.

[0039] In the present application, the anhydrous gypsum used is prepared by adding sulfuric acid to a solid-liquid mixed system of calcium sulfate dihydrate produced by sulfuric acid leaching of phosphate rock, and then undergoing a crystallization reaction. This method directly utilizes the solid-liquid mixed system in the production of wet phosphoric acid as a raw material, wherein a large amount of metal salts and the remaining sulfuric acid formed by the acidolysis of phosphate rock powder are not filtered or washed away, and can directly act as nucleating agents and crystallization agents during the crystallization process, thereby promoting the crystallization of calcium sulfate dihydrate to anhydrous calcium sulfate. The anhydrous gypsum obtained by the liquid phase crystallization method is type II anhydrous gypsum, type II anhydrous gypsum with D90≤30µm, for example, the D90 of the anhydrous gypsum is 1µm, 2µm, 5µm, 10µm, 15µm, 20µm, 25µm, 30µm or any point value or range less than or equal to 30µm, and the bulk density of type II anhydrous gypsum is 0.5-1.5g / cm 3 For example, the bulk density of type II anhydrous gypsum is 0.5 g / cm 3 , 0.8g / cm 3 , 1.0g / cm 3 , 1.2g / cm 3 , 1.5g / cm 3 or 0.5-1.5g / cm 3 The oil absorption value is any point value or range between 40 and 60 ml / 100 g, for example, the oil absorption value is 40 ml / 100 g, 45 ml / 100 g, 50 ml / 100 g, 55 ml / 100 g, 60 ml / 100 g or any point value or range between 40 and 60 ml / 100 g. The anhydrous gypsum used in the present application is beneficial to further improve the strength of the self-leveling mortar.

[0040] Furthermore, in some embodiments, the in-situ activator includes one or more of hemihydrate gypsum and dihydrate gypsum; and / or the chemical activator includes one or more of acidic activators and alkaline activators.

[0041] In the embodiments of the present application, the acidic activator accelerates the dissolution process of anhydrous gypsum by reducing the activation energy required for the dissolution of anhydrous gypsum, and at the same time reduces the potential of the solid-liquid interface of the hydration system through the electrolyte effect, which is beneficial to improving the early strength of the self-leveling mortar and shortening the final setting time; the alkaline activator can promote the acceleration of the hydration reaction of anhydrous gypsum and the generation of new products, so that the strength of the obtained self-leveling mortar is improved, and the water resistance and durability are improved; compared with the acidic activator, the alkaline activator will not have the acid regurgitation phenomenon, and the strength of the self-leveling mortar is improved to a higher degree; the acidic activator, the alkaline activator and the in-situ activator synergistically help promote the hydration and hardening process of anhydrous gypsum and improve the strength of the self-leveling mortar.

[0042] Further, in some embodiments, the hemihydrate gypsum includes one or more of α-gypsum and β-gypsum; and / or the acidic activator includes one or more of potassium sulfate, sodium sulfate, and alum; and / or the alkaline activator includes one or more of cement, steel slag, slag, fly ash, and calcium oxide.

[0043] In the embodiments of the present application, the use of α gypsum as an in-situ activator is more conducive to improving the strength of gypsum-based self-leveling mortar, and the use of β gypsum as an in-situ activator can improve the strength of gypsum-based self-leveling mortar with low cost; the acidic activator and alkaline activator of this embodiment are easy to obtain, which is conducive to expanding production.

[0044] Further, in some embodiments, the in-situ activator includes hemihydrate gypsum, and the chemical activator includes a mixture of calcium oxide and alum; and / or, the in-situ activator includes hemihydrate gypsum, and the chemical activator includes cement.

[0045] In the embodiments of the present application, the compound combination of semi-hydrated gypsum and some chemical activators is more conducive to improving the strength of the gypsum-based self-leveling mortar, and prolonging the initial setting time and shortening the final setting time.

[0046] Further, in some embodiments, the mass ratio of calcium oxide to alum is 5:(2-3); for example, the mass ratio of calcium oxide to alum is 5:2, 5:2.5, 5:3 or any ratio within the range of 5:(2-3).

[0047] In the embodiments of the present application, within a limited ratio, it is beneficial to extend the initial setting time and shorten the final setting time of the gypsum-based self-leveling mortar; within the limited dosage range, the hydration rate of anhydrous gypsum is high, which is more beneficial to improving the strength of the self-leveling mortar, but if the amount of calcium oxide is too much, the initial setting time will be shortened, and if the amount of calcium oxide is too little, the strength improvement will not be obvious.

[0048] Furthermore, in some embodiments, based on 100 parts of the sum of the masses of anhydrous gypsum, chemical activator and in-situ activator, the mass fraction of the chemical activator is 6-10 parts; and / or, the mass ratio of anhydrous gypsum to in-situ activator is 9:(0.5-1.5).

[0049] In the embodiments of the present application, too much chemical activator or in-situ activator may result in the setting time failing to meet the requirements, while too little chemical activator or in-situ activator may result in the strength of the gypsum-based self-leveling mortar being reduced.

[0050] Furthermore, in some embodiments, 0.05-0.1 parts of retarder are included by weight. For example, the mass fraction of the retarder is 0.05 parts, 0.06 parts, 0.1 parts or any point in the range of 0.05-0.1 by weight.

[0051] In the embodiments of the present application, the retarder can increase the fluidity of the self-leveling mortar, reduce the generation of bubbles and holes, and help improve the density and strength of the self-leveling mortar.

[0052] Further, in some embodiments, the water reducer includes one or more of a naphthalene water reducer and a polycarboxylic acid water reducer; and / or, the defoamer includes one or more of a silicone defoamer and a high-carbon alcohol defoamer, and the high-carbon alcohol defoamer includes polyethylene glycol; and / or, the stabilizer includes one or more of hydroxypropyl methylcellulose, sodium bentonite, and sodium polyacrylate; and / or, the retarder includes a protein retarder.

[0053] In the embodiments of the present application, the water reducing agent is helpful to reduce the friction between anhydrous gypsum and other components to promote the bonding between the components and improve the strength of the self-leveling mortar. The protein retarder has a relatively mild inhibitory effect on the growth of gypsum crystals, and the growth rate of each crystal face is simultaneously inhibited, and the crystal morphology does not change much, so the loss of the strength of the self-leveling mortar is smaller.

[0054] In a second aspect, the present application provides a method for preparing a phosphogypsum-based self-leveling mortar, comprising the steps of: providing a plurality of raw materials, and blending the plurality of raw materials to obtain a mixture; Add water to the mixture and stir evenly to obtain phosphogypsum-based self-leveling mortar; Among them, the various raw materials include, by mass, 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, 0.2-0.4 parts of water reducer and / or 0.05-0.1 parts of retarder.

[0055] In this embodiment, before the step of blending the multiple raw materials, there is also a step of drying the multiple raw materials. Blending after drying is beneficial for uniform dispersion and mixing of the raw material components in a dry powder state. Thereafter, when water is added and stirred for hydration, the preparation efficiency of the self-leveling mortar can be improved.

[0056] In a third aspect, the present application provides an application of phosphogypsum-based self-leveling mortar in the construction field.

[0057] In the embodiments of the present application, gypsum-based self-leveling mortar is used as a high-strength self-leveling mortar in the construction field. It has high flexural strength and compressive strength, and the initial and final setting times meet the construction requirements, thereby improving the durability and construction convenience of the self-leveling layer.

[0058] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0059] 1. Preparation method In this application, the preparation method of anhydrous gypsum is as follows: phosphate rock powder is used as raw material, and an appropriate amount of sulfuric acid solution is added to the reactor; wherein: the liquid-solid ratio of sulfuric acid solution to phosphate rock powder in the reaction system is controlled to be 5L:1kg; after reacting at 80°C for 1h, an acid leaching system containing calcium sulfate dihydrate is formed; sulfuric acid is added to the acid leaching system, and a crystallization reaction is carried out at 100°C for 1h, and the mass concentration of sulfuric acid in the system after the crystallization reaction is 25%; the product after the reaction is completed is filtered and washed conventionally to obtain anhydrous calcium sulfate. According to the provisions of GB / T5484-2012 "Chemical Analysis Method for Gypsum", the obtained anhydrous gypsum is measured to be type II anhydrous gypsum, D90 is 30µm, and the bulk density is 0.5g / cm 3 , the oil absorption value is 40ml / 100g.

[0060] Example 1 A phosphogypsum-based self-leveling mortar comprises the following components in parts by mass: 82 parts of anhydrous gypsum, 10 parts of beta-gypsum, 5 parts of calcium oxide, 3 parts of alum, 0.06 parts of polyethylene glycol, 0.1 parts of hydroxypropyl methylcellulose, and 0.4 parts of a naphthalene-based water reducer.

[0061] A preparation method of phosphogypsum-based self-leveling mortar comprises the following steps: drying anhydrous gypsum with a particle size D90 of 30 µm after grinding at 60°C, beta gypsum, calcium oxide, alum, polyethylene glycol, a naphthalene water reducer and hydroxypropyl methylcellulose respectively, blending the mixture, adding water at a material-liquid ratio of 1:4 and stirring the mixture evenly to obtain the phosphogypsum-based self-leveling mortar.

[0062] Embodiment 2-4 A phosphogypsum-based self-leveling mortar, other contents of which are the same as those of Example 1, except that the amount of alum used is 1 part, 2 parts, and 5 parts.

[0063] Embodiment 5-6 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the amount of calcium oxide used is 2 parts or 3 parts.

[0064] Embodiment 7-9 A phosphogypsum-based self-leveling mortar, other contents of which are the same as those of Example 1, except that the amount of beta gypsum used is 5 parts, 8 parts, and 15 parts.

[0065] Example 10 A phosphogypsum-based self-leveling mortar, other contents of which are the same as those of Example 1, except that a naphthalene-based water reducing agent is not included.

[0066] Embodiment 11 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the naphthalene-based water-reducing agent is replaced by a melamine-based water-reducing agent.

[0067] Example 12 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that β-gypsum is replaced by α-gypsum.

[0068] Embodiment 13 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that calcium oxide is replaced by steel slag, and alum is replaced by cement.

[0069] Comparative Example 1 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the amount of calcium oxide used is 10 parts and the amount of alum used is 6 parts.

[0070] Comparative Example 2 A phosphogypsum-based self-leveling mortar, other contents of which are the same as those of Example 1, except that the amount of calcium oxide is 2.5 parts and the amount of alum is 1.5 parts.

[0071] Comparative Examples 3-4 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the amounts of beta gypsum used are 0 parts and 20 parts.

[0072] Comparative Example 5 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the amount of beta gypsum is 5 parts, the amount of calcium oxide is 2.5 parts, and the amount of alum is 1.5 parts.

[0073] Comparative Example 6 A phosphogypsum-based self-leveling mortar, the other contents of which are the same as those of Example 1, except that the amount of beta gypsum is 20 parts, the amount of calcium oxide is 10 parts, and the amount of alum is 6 parts.

[0074] 2. Test Method 1. The flexural strength and compressive strength of the self-leveling mortar obtained in each embodiment and comparative example at different times (1d, 28d) were tested according to the test method of GB / T 29756-2013. The results are shown in Table 1; 2. The initial setting time and final setting time of the self-leveling mortar obtained in each embodiment and comparative example were tested according to the test method of GB9777-88, wherein the self-leveling mortar requirement standard is: satisfying the initial setting time ≥ 2h and the final setting time ≤ 8h; the test results are shown in Table 1.

[0075] III. Analysis of test results of various embodiments and comparative examples Table 1 Test results of different self-leveling mortars

[0076] As can be seen from Table 1, compared with Example 1, in Examples 2-4, the amount of calcium oxide remains unchanged. As the amount of alum increases, the final setting time is shortened, the initial setting time is not greatly affected, and the flexural strength and compressive strength show an upward trend; in Examples 5-6, compared with Example 1, the amount of alum remains unchanged. As the amount of calcium oxide increases, the initial setting time is first extended and then shortened, the final setting time is gradually shortened, and the flexural strength and compressive strength are gradually improved; in Examples 7-9, compared with Example 1, the amount of chemical stimulant remains unchanged. As the amount of in-situ stimulant increases, the initial setting time is shortened, the final setting time is slightly decreased, but the flexural strength and compressive strength show a trend of first increasing and then decreasing; in Examples 10-11, compared with Example 1, it is shown that the use of naphthalene water reducer is more conducive to the improvement of 28d flexural strength and 28d compressive strength; in Examples 12-13 Compared with Example 1, the composite components of the stimulant are replaced, and the stimulant combination of Example 12 is more conducive to the improvement of flexural strength and compressive strength; compared with Example 1, the dosage of the in-situ stimulant in Comparative Example 1 remains unchanged, but more chemical stimulants are used, resulting in a significant shortening of the initial setting time and the final setting time; compared with Example 1, the dosage of the chemical stimulant is reduced in Comparative Example 2, and the initial setting and final setting times are prolonged, while the compressive strength and flexural strength are decreased; compared with Example 1, Comparative Example 3 does not use an in-situ stimulant, and the initial setting time is prolonged, while the compressive strength and flexural strength are decreased; compared with Example 1, the dosage of the two stimulants in Comparative Example 5 is equally reduced, and its flexural strength and compressive strength are both reduced; compared with Example 1, the dosage of the two stimulants in Comparative Example 6 is equally increased, which will cause the initial setting time and the final setting time to be too short.

[0077] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A phosphogypsum-based self-leveling mortar, characterized in that: The invention comprises the following components by weight: 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, and 0.2-0.4 parts of water reducer; wherein the anhydrous gypsum is type II anhydrous gypsum with D90≤30µm, and the bulk density of the type II anhydrous gypsum is 0.5-1.5g / cm 3 , the oil absorption value is 40-60ml / 100g.

2. The phosphogypsum-based self-leveling mortar according to claim 1, characterized in that: The in-situ activator includes one or more of hemihydrate gypsum and dihydrate gypsum; and / or, The chemical stimulant includes one or more of an acidic stimulant and an alkaline stimulant.

3. The phosphogypsum-based self-leveling mortar according to claim 2, characterized in that: The hemihydrate gypsum includes one or more of α-gypsum and β-gypsum; and / or, The acidic stimulator includes one or more of potassium sulfate, sodium sulfate and alum; and / or, The alkaline activator includes one or more of cement, steel slag, slag, fly ash and calcium oxide.

4. The phosphogypsum-based self-leveling mortar according to claim 3, characterized in that: The in-situ activator comprises hemihydrate gypsum, and the chemical activator comprises a mixture of calcium oxide and alum; and / or, The in-situ activator includes hemihydrate gypsum, and the chemical activator includes cement.

5. The phosphogypsum-based self-leveling mortar according to claim 4, characterized in that: The mass ratio of the calcium oxide to the alum is 5:(2-3).

6. The phosphogypsum-based self-leveling mortar according to claim 1, characterized in that: Based on 100 parts by weight of the sum of the anhydrous gypsum, the chemical activator and the in-situ activator, the weight of the chemical activator is 6-10 parts; and / or, The mass ratio of the anhydrous gypsum to the in-situ activator is 9:(0.5-1.5).

7. The phosphogypsum-based self-leveling mortar according to claim 1, characterized in that: Calculated by weight, it also includes 0.05-0.1 parts of retarder.

8. The phosphogypsum-based self-leveling mortar according to claim 7, characterized in that: The water reducer includes one or more of a naphthalene water reducer and a polycarboxylic acid water reducer; and / or, The defoaming agent includes one or more of an organosilicon defoaming agent and a high-carbon alcohol defoaming agent; and / or, The stabilizer includes one or more of hydroxypropyl methylcellulose, sodium bentonite, and sodium polyacrylate; and / or, The retarder includes a protein retarder.

9. A method for preparing the phosphogypsum-based self-leveling mortar according to any one of claims 1 to 8, characterized in that: Includes steps: Providing a plurality of raw materials, and blending the plurality of raw materials to obtain a mixed material; Add water to the mixture and stir evenly to obtain the phosphogypsum-based self-leveling mortar; Among them, the various raw materials include, by mass, 75-90 parts of anhydrous gypsum, 5-15 parts of in-situ activator, 5-10 parts of chemical activator, 0.06-0.1 parts of defoamer, 0.06-0.1 parts of stabilizer, 0.2-0.4 parts of water reducer and / or 0.05-0.1 parts of retarder.

10. Use of the phosphogypsum-based self-leveling mortar according to any one of claims 1 to 8 in the field of construction.

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