CN114605105A - Dry-mixed mortar thickening agent and preparation method thereof - Google Patents

Abstract

The application relates to the technical field of dry powder mortar, and particularly discloses a dry powder mortar thickening agent and a preparation method thereof. The dry powder mortar thickening agent is prepared from the following raw materials in parts by weight: 20-40 parts of limestone powder; 5-15 parts of nano kaolin; 4-10 parts of silicon tetrachloride; 2-5 parts of a modifier, wherein the modifier comprises a surfactant and a coupling agent which are mixed according to the mass ratio of (1-3) to (2-4); the preparation method comprises the following steps: s1, primary mixing: mixing limestone powder and a modifier according to a formula to obtain a primary mixed material; s2, blending: and mixing the primary mixed material, the nano kaolin and the silicon tetrachloride to obtain the dry powder mortar thickening agent. The composition/product of the application has the advantage of improving the strength of the mortar; in addition, the preparation method has the advantages of simple operation and wide application.

Description

Dry-mixed mortar thickening agent and preparation method thereof

Technical Field

The application relates to the technical field of dry powder mortar, in particular to a dry powder mortar thickening agent and a preparation method thereof.

Background

Dry-mixed mortar is a granular or powdery material prepared by physically mixing dried and screened quartz sand, cement, polymer additive and the like according to a certain proportion, and the granular or powdery material is transported to a construction site in a bag or in bulk form and is mixed with water to be directly used, and the dry-mixed mortar is also called as mortar dry powder, dry-mixed mortar and dry-mixed powder. The dry powder mortar plays roles of bonding, lining, protection and decoration in a thin layer in the construction industry, and is widely applied to construction and decoration engineering.

In the related technology, in order to increase the consistency between the components when dry-mixed mortar is mixed, limestone powder is usually added into the dry-mixed mortar as a thickening agent, but because the surface of limestone is hydrophilic and oleophobic, the polarity is strong, and the particle size of the limestone powder is small and easy to agglomerate, the compatibility between the limestone powder and a polymer in the dry-mixed mortar is poor, so that the strength of the mortar is affected.

Disclosure of Invention

In order to improve the strength of mortar, the application provides a dry powder mortar thickening agent and a preparation method thereof.

In a first aspect, the present application provides a dry-mixed mortar thickening agent, which adopts the following technical scheme:

a dry powder mortar thickening agent is prepared from the following raw materials in parts by weight:

20-40 parts of limestone powder;

5-15 parts of nano kaolin;

4-10 parts of silicon tetrachloride;

2-5 parts of a modifier, wherein the modifier comprises a surfactant and a coupling agent which are mixed according to the mass ratio of (1-3) to (2-4).

By adopting the technical scheme, the limestone powder is added into the dry powder mortar, and the consistency of the mortar can be increased after the limestone powder meets water, so that the thickening purpose is achieved.

The cement contains calcium oxide, the limestone powder contains calcium oxide and calcium carbonate, and after water is added into the dry powder mortar, the calcium oxide and the calcium carbonate react with water to generate alkaline calcium hydroxide and release heat. The nano kaolin is an amorphous silicon-aluminum compound, and under the excitation of alkaline conditions, the amorphous silicon-aluminum compound is depolymerized and then polymerized again to form a stable and extremely high silicate network structure. Meanwhile, active alumina and silica in the nano kaolin react with calcium hydroxide which has hydration, so that limestone powder and cement are promoted to hydrate, calcium aluminate hydrate and calcium silicate hydrate are generated, the calcium aluminate hydrate and the calcium silicate hydrate both have gelling performance, and the thickening effect can be further increased; in addition, the hydrated calcium aluminate and the hydrated calcium silicate reduce a calcium hydroxide layer coated outside the raw materials, so that the effect of improving the structural compactness of the mortar is achieved, and the strength of the mortar is further improved.

The silicon tetrachloride is hydrolyzed when meeting water, and the heat emitted in the process of generating calcium hydroxide by reacting calcium oxide and calcium carbonate when meeting water can also promote the hydrolysis reaction of the silicon tetrachloride to generate silicic acid and hydrochloric acid. Silicic acid reacts with calcium hydroxide to generate hydrated calcium silicate, so that the strength of the mortar is further improved; the hydrochloric acid reacts with the calcium hydroxide to generate calcium chloride, the calcium chloride can reduce the freezing point of water, so that the freeze-thaw resistance of the mortar is improved, the strength of the mortar is improved, the service life of the mortar is prolonged, the concentration of calcium ions in the mortar can be increased, and according to the Lexhlet principle and the same ion effect, the loss of calcium aluminate hydrate and calcium silicate hydrate in the mortar is reduced by increasing the concentration of the calcium ions in the mortar, so that the strength of the mortar is further improved.

In the modifier, the coupling agent contains two groups, one is an inorganic filler-philic group, and the other is an organic polymer-philic group. Under the action of the coupling agent, inorganic substances such as limestone powder and the like can form good interface combination with polymers in the dry powder mortar, so that the strength of the mortar is improved. In the molecular structure of the surfactant, one end of a molecule contains polar groups such as carboxyl and the like, can be adsorbed or chemically reacted with inorganic substances such as limestone powder and the like, and has good hydrophilicity, so that the limestone powder is not easy to agglomerate; the other end of the molecule is long-chain alkyl, and the structure is similar to that of a polymer molecule, so that the polymer molecule has certain compatibility with the polymer, the compatibility of inorganic matters such as lime powder and the like with the polymer in the dry powder mortar can be promoted, the dispersibility and uniformity of each component in the mortar are improved, and the effect of improving the strength of the mortar is further achieved.

Preferably, the coupling agent comprises a titanate coupling agent, a silane coupling agent and an aluminate coupling agent which are mixed according to the mass ratio of (1-3) to (3-6) to (1-4).

By adopting the technical scheme, the titanate coupling agent comprises an inorganic group and an organic group, wherein the inorganic group comprises a short-chain alkoxy group easy to hydrolyze or a chelating group with certain stability to water, and can act with the bound water in the calcium aluminate hydrate and the calcium silicate hydrate to be bound on the surfaces of the calcium aluminate hydrate and the calcium silicate hydrate; the organophilic group and the polymer are subjected to chemical reaction to couple the hydrated calcium aluminate and the hydrated calcium silicate with the polymer, so that the mortar with strong bonding force is formed, and the strength of the mortar is improved.

The inorganic group of the silane coupling agent can form good combination with the hydrated calcium silicate, thereby enabling the hydrated calcium silicate to form good combination with the polymer in the dry powder mortar and improving the strength of the mortar.

The aluminate coupling agent is non-toxic, has high thermal decomposition temperature and high reaction activity with the surface of the inorganic filler, so that the inorganic components in the dry powder mortar can form stable and good combination with the polymer.

Through the compounding of the three coupling agents, the binding capacity between the thickening component and the polymer in the dry-mixed mortar is synergistically improved, so that a good thickening effect is achieved, and the strength of the mortar is improved.

Preferably, the modifier further comprises a fibrous body comprising glass fibers and gypsum fibers.

By adopting the technical scheme, firstly, the coupling agent can be coupled with the fiber body while being combined with the inorganic components and the polymer in the dry powder mortar, and the fiber body can be tangled on quartz sand and cement particles in the mortar, so that the bonding force and the integrity of each component in the mortar are improved, and the strength of the mortar is improved.

In addition, the glass fiber has good heat resistance, good chemical resistance, high tensile strength and good processability; the gypsum fiber has good reinforcing, toughening, thickening, heat resisting, wear resisting, oil resisting and thixotropic properties, so the glass fiber and the gypsum fiber are beneficial to improving the comprehensive performance of the mortar, and the glass fiber and the gypsum fiber can be well combined with a silane coupling agent, thereby the strength of the mortar can be improved.

Preferably, the fiber body is a pretreated fiber body, and the pretreatment comprises the following steps: soaking the fiber body in 10-30% hydrochloric acid by mass, filtering, taking filter residue, washing the filter residue, and drying to obtain the pretreated fiber body.

By adopting the technical scheme, the surface of the pretreated fiber body can form an uneven pit-shaped structure, so that on one hand, the contact area with the coupling agent is increased, and the binding force between the fiber body and the coupling agent can be improved; on the other hand, a rough surface structure is formed, so that the chelating force of the fiber body and other components such as a coupling agent can be increased, and the strength of the mortar is further improved.

Preferably, the coupling agent and the surfactant are both solids, the particle size of the coupling agent is larger than that of the surfactant, and the surfactant is filled in gaps of the coupling agent.

By adopting the technical scheme, the coupling agent and the surfactant are both solid and are easy to add and use. In addition, the surfactant is filled in the gaps of the coupling agent, so that the coupling agent positioned on the outer side can be better contacted with the fiber body to generate coupling, and the surfactant seeps out from the gaps after meeting water, so that the hydrophilic property of the inorganic component is improved, and the surfactant is better dispersed in the rest components in the mortar.

Preferably, the surfactant comprises one or two of fatty alcohol-polyoxyethylene ether and sodium methylene-bis-naphthalene sulfonate.

By adopting the technical scheme, the fatty alcohol-polyoxyethylene ether and the methylene dinaphthalene sodium sulfonate both have good permeability, are easy to seep out from gaps of the coupling agent and contact with inorganic components, and improve the hydrophilicity of the inorganic components, so that the dispersibility and the uniformity of each component of the mortar are improved, and the strength of the mortar is improved.

Preferably, the coupling agent further comprises gelatin.

By adopting the technical scheme, the gelatin is added into the coupling agent and swells after absorbing water, so that the surfactant in the gap of the coupling agent is extruded, and the surfactant is convenient to seep out of the gap of the coupling agent.

In a second aspect, the application provides a preparation method of a dry-mixed mortar thickening agent, which adopts the following technical scheme:

a preparation method of a dry powder mortar thickening agent comprises the following steps:

s1, primary mixing: mixing limestone powder and a modifier according to a formula to obtain a primary mixed material;

s2, blending: and mixing the primary mixed material, the nano kaolin and the silicon tetrachloride to obtain the dry powder mortar thickening agent.

By adopting the technical scheme, the modifier is mixed with the limestone powder in the step S1, so that the modifier is dispersed in the limestone powder; and mixing the components in the step S2 to finally obtain the mortar thickening agent with uniform components, and the preparation method is simple and has wide application.

In summary, the present application has the following beneficial effects:

1. according to the method, limestone powder, nano kaolin, silicon tetrachloride and a modifier are added into a thickening agent to form a stable and extremely high silicate network structure, and meanwhile, the nano kaolin promotes the hydration of the limestone powder and cement to further generate hydrated calcium aluminate and hydrated calcium silicate; in addition, the calcium aluminate hydrate and the calcium silicate hydrate reduce a calcium hydroxide layer coated outside the raw materials, so that the effect of improving the structural compactness of the mortar is achieved, and the strength of the mortar is improved;

silicic acid generated by hydrolysis of the silicon tetrachloride when water is in contact reacts with calcium hydroxide to generate calcium silicate hydrate, so that the strength of the mortar is further improved; the generated hydrochloric acid reacts with calcium hydroxide to generate calcium chloride, the calcium chloride can reduce the freezing point of water, so that the freeze-thaw resistance of the mortar is improved, and the calcium chloride can increase the concentration of calcium ions in the mortar, so that the strength of the mortar is further improved.

In the modifier, the compatibility of inorganic substances such as lime powder and the like with polymers in dry powder mortar can be promoted, the dispersibility and uniformity of each component in the mortar are improved, and the effect of improving the strength of the mortar is further achieved.

2. The fiber body is preferably added into the modifier, the coupling agent can be coupled with the fiber body while being combined with inorganic components and polymers in dry powder mortar, and the fiber body can be tangled on quartz sand and cement particles in the mortar, so that the binding force and integrity of each component in the mortar are improved, and the strength of the mortar is further improved.

3. In the application, the coupling agent is preferably filled in gaps of the coupling agent, and the coupling agent comprises gelatin, so that the coupling agent positioned on the outer side can be better contacted with a fiber body to generate coupling, and after the gelatin absorbs water, the gelatin swells so as to extrude the surfactant in the gaps of the coupling agent, so that the surfactant is easy to seep out of the gaps, the hydrophilic property of the inorganic component is improved, and the inorganic component is better dispersed in other components in the mortar.

Detailed Description

The present application will be described in further detail with reference to examples.

In the examples of the present application, the drugs used are shown in table 1:

table 1 pharmaceutical products according to embodiments of the present application

Preparation example of coupling agent

Preparation example 1

As the coupling agent, 15kg of a commercially available titanate coupling agent was used.

Preparation example 2

As the coupling agent, 5kg of a commercially available silane coupling agent was used.

Preparation example 3

As the coupling agent, 5kg of a commercially available aluminate coupling agent was used.

Preparation example 4

Commercially available 2kg of titanate coupling agent and 4.5kg of silane coupling agent were mixed to prepare a coupling agent.

Preparation example 5

Commercially available 2kg of titanate coupling agent and 2.5kg of aluminate coupling agent were mixed to obtain a coupling agent.

Preparation example 6

A commercially available silane coupling agent (4.5 kg) and an aluminate coupling agent (2.5 kg) were mixed together to prepare a coupling agent.

Preparation example 7

Commercially available 1kg of titanate coupling agent, 3kg of silane coupling agent and 1kg of aluminate coupling agent are mixed to serve as the coupling agent.

Preparation examples 8 to 9

Preparation examples 8 to 9 differed from preparation example 7 in that: the mass ratio of the titanate coupling agent, the silane coupling agent and the aluminate coupling agent in preparation examples 8-9 is different from that in preparation example 7, and specifically as follows:

preparation example 8: 2kg of a titanate coupling agent, 4.5kg of a silane coupling agent and 2.5kg of an aluminate coupling agent;

preparation example 9: 3kg of titanate coupling agent, 6kg of silane coupling agent and 4kg of aluminate coupling agent.

Preparation example 10

Preparation example 10 differs from preparation example 8 in that preparation example 10 further includes 2kg of gelatin, and a commercially available coupling agent of 2kg of titanate coupling agent, 4.5kg of silane coupling agent, 2.5kg of aluminate coupling agent and 2kg of gelatin are mixed to obtain the coupling agent.

Preparation example of fibrous body

Preparation example 11

As the fibrous body, commercially available 10kg of glass fiber was used.

Preparation example 12

As the fibrous body, 10kg of commercially available gypsum fibers were used.

Preparation example 13

Commercially available 5kg of glass fibers and 5kg of gypsum fibers were mixed to prepare a fibrous body.

Preparation example 14

As the fibrous body, 10kg of commercially available carbon fiber was used.

Preparation example 15

The difference between the preparation example and the preparation example 13 is that the fiber body of the preparation example is a pretreated fiber body, and the pretreatment steps are as follows: mixing 5kg of glass fiber and 5kg of gypsum fiber, soaking in 20% hydrochloric acid by mass fraction, filtering after 5min, taking filter residue, washing the filter residue with water for 3 times, and drying at room temperature for 24h to obtain the pretreated fibrous body.

Preparation example of surfactant

Preparation example 15

Commercially available 15kg of fatty alcohol-polyoxyethylene ether is used as the surfactant after being ground to a particle size of less than 10 microns.

Preparation example 16

Commercially available sodium methylenedinaphthalenesulfonate (5 kg) was used as a surfactant after grinding to a particle size of less than 10 μm.

Preparation example 17

Commercially available 2.5kg of fatty alcohol-polyoxyethylene ether and 2.5kg of methylene bis-naphthalene sodium sulfonate are mixed and ground until the particle size is less than 10 mu m, and then the mixture is used as a surfactant.

Preparation example 18

Commercially available 5kg of sodium dodecylbenzenesulfonate was used as a surfactant after grinding to a particle size of less than 10 μm.

Preparation example of modifier

Preparation example 19

1kg of the surfactant of preparation example 15 and 2kg of the coupling agent of preparation example 1 were stirred and mixed to obtain a modifier.

Preparation example 20

2kg of the surfactant of preparation example 15 and 3kg of the coupling agent of preparation example 1 were mixed by stirring to obtain a modifier.

Preparation example 21

3kg of the surfactant of preparation example 15 and 4kg of the coupling agent of preparation example 1 were stirred and mixed to obtain a modifier.

Preparation examples 22 to 33

The preparation examples 22 to 33 are different from the preparation example 20 in the following details as to the surfactant and the coupling agent:

TABLE 2 selection of surfactants and coupling Agents in preparation 20 and preparations 22-33

Preparation example 34

The difference between the preparation example and the preparation example 33 is that the preparation example also comprises a fibrous body, and the preparation example is prepared by the following method:

2kg of the surfactant of preparation example 17, 3kg of the coupling agent of preparation example 10 and 1.5kg of the fiber of preparation example 11 were mixed by stirring to obtain a modifier.

Preparation examples 35 to 38

Preparation examples 35 to 38 differ from preparation example 34 in the fiber body used, specifically, as follows:

preparation example 35: the fibrous body of preparation example 12 was used;

preparation example 36: the fibrous body of preparation example 13 was used;

preparation example 37: the fiber of preparation example 14 was used.

Preparation example 38: the fiber of preparation example 15 was used.

Examples

Example 1

A dry powder mortar thickening agent is prepared from the following raw materials:

20kg of limestone powder;

5kg of nano kaolin;

4kg of silicon tetrachloride;

2kg of modifier of preparation example 19.

A preparation method of a dry powder mortar thickening agent comprises the following steps:

s1, primary mixing: mixing and stirring limestone powder and a modifier according to a formula to obtain a primary mixed material;

s2, blending: and mixing and stirring the primary mixed material, the nano kaolin and the silicon tetrachloride to obtain the dry powder mortar thickening agent.

Example 2

The difference between this embodiment and embodiment 1 is that the dry powder mortar thickener in this embodiment has different raw materials in quality, specifically as follows:

30kg of limestone powder;

10kg of nano kaolin;

7kg of silicon tetrachloride;

3.5kg of modifier of preparation 19.

Example 3

The difference between this embodiment and embodiment 1 is that the quality of the dry powder mortar thickener raw material in this embodiment is different, specifically as follows:

40kg of limestone powder;

15kg of nano kaolin;

10kg of silicon tetrachloride;

5kg of modifier of preparation example 19.

Examples 4 to 21

Examples 4-21 differ from example 2 in the modifier selected, as shown in table 3 below:

TABLE 3 selection of modifiers in examples 2, 4-21

Comparative example

Comparative example 1

This comparative example differs from example 2 in that the modifier of this comparative example contains only 5kg of the surfactant of preparation example 15.

Comparative example 2

This comparative example differs from example 2 in that the modifier of this comparative example contains only 5kg of the coupling agent of preparation example 1.

Comparative example 3

This comparative example differs from example 2 in that it uses a commercially available zeolite powder instead of nano kaolin.

Performance test

Detection method

Mixing 52kg of quartz sand, 30kg of cement, 10kg of cellulose ether, 5kg of lignin, 6kg of dry mortar thickening agent and 16kg of water, and stirring to obtain mortar; and (3) testing the consistency and the cubic compressive strength of the mortar by referring to a standard 'basic performance test method of building mortar' JGJ/70-2009.

TABLE 4 Performance test Table

The following examples 1 to 3 were compared, and the differences between examples 1 to 3 were that the dry mortar thickener raw materials were mixed in different proportions, which indicated that the raw materials in example 2 were mixed in the best proportions because of the highest consistency and compressive strength of example 2.

Comparing examples 4-5 with example 2, examples 4-5 differ from example 2 in the ratio of surfactant to coupling agent in the modifier, and since example 4 has the highest consistency and compressive strength, it is shown that the ratio of surfactant to coupling agent in the modifier of example 4 is the best.

Example 4 is compared with examples 6 to 8, and example 4 differs from examples 6 to 8 in the surfactant used. The consistency and the compressive strength of the embodiment 4 and the embodiments 6 to 7 are higher than those of the embodiment 8, which shows that the fatty alcohol-polyoxyethylene ether and the methylene dinaphthalene sodium sulfonate both have good permeability, are easy to seep out from gaps of the coupling agent and contact with inorganic components, and improve the hydrophilicity of the inorganic components, so that the dispersibility and the uniformity of all the components of the mortar are improved, and the strength of the mortar is improved. In addition, the consistency and the compressive strength of the product in example 7 are the highest, which shows that the surfactant compounded by fatty alcohol-polyoxyethylene ether and methylene dinaphthalene sodium sulfonate is better.

Comparing example 7 with examples 9 to 14, wherein examples 7 and 9 to 14 are different in that the coupling agents are different, and example 14 has the highest consistency and compressive strength, which indicates that the titanate coupling agent can be combined with the binding water in the calcium aluminate hydrate and the calcium silicate hydrate to be bound on the surfaces of the calcium aluminate hydrate and the calcium silicate hydrate by the compound of the titanate coupling agent, the silane coupling agent and the aluminate coupling agent; the organophilic group and the polymer are subjected to chemical reaction to couple the hydrated calcium aluminate and the hydrated calcium silicate with the polymer, so that the mortar with strong bonding force is formed, and the strength of the mortar is improved. The inorganic group of the silane coupling agent can form good combination with the hydrated calcium silicate, thereby enabling the hydrated calcium silicate to form good combination with the polymer in the dry powder mortar and improving the strength of the mortar. The aluminate coupling agent and the inorganic filler have high surface reaction activity, so that the inorganic components in the dry powder mortar can form stable and good combination with the polymer. The binding capacity between the thickening component and the polymer in the dry powder mortar is synergistically improved, so that a good thickening effect is achieved, and the strength of the mortar is improved.

Examples 14-16 were compared, and examples 14-16 were different in the compounding ratio of the titanate coupling agent, the silane coupling agent and the aluminate coupling agent. The consistency and compressive strength of example 15 are the highest, indicating that the formulation of titanate coupling agent, silane coupling agent and aluminate coupling agent is the best for example 15.

Comparing example 17 with example 15, example 17 is different from example 15 in that the coupling agent of example 17 further comprises gelatin, and the consistency and compressive strength of example 17 are higher, which means that when gelatin is added to the coupling agent, the gelatin swells after absorbing water, thereby squeezing the surfactant in the gaps of the coupling agent, and further facilitating the surfactant to seep out from the gaps of the coupling agent, and improving the strength of the mortar.

Comparing examples 18-21 with example 17, examples 18-21 differ from example 17 in that the modifier of examples 18-21 further comprises a fibrous body, and the consistency and compressive strength of examples 18-21 are greater than those of example 17, which indicates that the coupling agent can be coupled with the inorganic component and the polymer in the dry mortar, and simultaneously can be coupled with the fibrous body, and the fibrous body can be entangled on quartz sand and cement particles in the mortar, thereby improving the bonding force and integrity of each component in the mortar, and further improving the strength of the mortar. In addition, the consistency and compressive strength of examples 18-20 are greater than example 21, indicating that both glass fibers and gypsum fibers can form good bonds with the silane coupling agent, thereby increasing the strength of the mortar.

Comparing the example 22 with the example 19, the difference between the example 22 and the example 19 is that the fiber body of the example 22 is the fiber body after pretreatment, and because the consistency and the compressive strength of the example 22 are both larger than those of the example 19, the fiber body after pretreatment can form an uneven pit-shaped structure on the surface, on one hand, the contact area with the coupling agent is increased, and the bonding force between the fiber body and the coupling agent can be improved; on the other hand, a rough surface structure is formed, so that the chelating force of the fiber body and other components such as a coupling agent can be increased, and the strength of the mortar is further improved.

Finally, comparative examples 1 to 3 were compared with example 2, and comparative examples 1 to 3 were different from example 2 in that the modifier of comparative example 1 contained only 5kg of the surfactant of preparation example 15, the modifier of comparative example 2 contained only 5kg of the coupling agent of preparation example 1, and comparative example 3 used commercially available zeolite powder instead of nano kaolin. Since example 2 has a greater consistency and compressive strength than comparative examples 1-3, the application is better illustrated.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims (8)

1. The dry powder mortar thickening agent is characterized by being prepared from the following raw materials in parts by weight:

20-40 parts of limestone powder;

5-15 parts of nano kaolin;

4-10 parts of silicon tetrachloride;

2-5 parts of a modifier, wherein the modifier comprises a surfactant and a coupling agent which are mixed according to the mass ratio of (1-3) to (2-4).

2. The dry-mixed mortar thickening agent according to claim 1, wherein: the coupling agent comprises a titanate coupling agent, a silane coupling agent and an aluminate coupling agent which are mixed according to the mass ratio of (1-3) to (3-6) to (1-4).

3. The dry-mixed mortar thickening agent according to claim 2, wherein: the modifier also includes a fiber body comprising glass fibers and gypsum fibers.

4. The dry-mixed mortar thickening agent according to claim 3, wherein: the fiber body is a pretreated fiber body, and the pretreatment comprises the following steps: soaking the fiber body in 10-30% hydrochloric acid by mass, filtering, taking filter residue, washing the filter residue, and drying to obtain the pretreated fiber body.

5. The dry-mixed mortar thickening agent according to claim 2, wherein: the coupling agent and the surfactant are both solid, the particle size of the coupling agent is larger than that of the surfactant, and the surfactant is filled in gaps of the coupling agent.

6. The dry-mixed mortar thickening agent according to claim 5, wherein: the surfactant comprises one or two of fatty alcohol-polyoxyethylene ether and methylene-bis-naphthalene sodium sulfonate.

7. The dry-mixed mortar thickening agent according to claim 5, wherein: the coupling agent also includes gelatin.

8. The preparation method of the dry mortar thickening agent according to any one of claims 1 to 7, characterized by comprising the following steps:

s1, primary mixing: mixing limestone powder and a modifier according to a formula to obtain a primary mixed material;

s2, blending: and mixing the primary mixed material, the nano kaolin and the silicon tetrachloride to obtain the dry powder mortar thickening agent.