CN114031326A - Alkali-free liquid accelerator based on superfine limestone suspension polyaluminum sulfate and preparation method thereof - Google Patents
Alkali-free liquid accelerator based on superfine limestone suspension polyaluminum sulfate and preparation method thereof Download PDFInfo
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- CN114031326A CN114031326A CN202111388613.3A CN202111388613A CN114031326A CN 114031326 A CN114031326 A CN 114031326A CN 202111388613 A CN202111388613 A CN 202111388613A CN 114031326 A CN114031326 A CN 114031326A
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- alkali
- free liquid
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/10—Accelerators; Activators
- C04B2103/12—Set accelerators
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- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
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- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention relates to an alkali-free liquid accelerator based on superfine limestone suspension polyaluminium sulfate and a preparation method thereof, wherein the alkali-free liquid accelerator comprises the following raw materials in percentage by mass: 55-61% of polymeric aluminum sulfate octadecahydrate, 9.7-10.7% of light limestone powder, 0.6-1.1% of organic alkali, 0.8-2.2% of polycarboxylic acid water reducing agent, 0.5-0.8% of thickening agent and 24.2-33.4% of water. The alkali-free liquid accelerator provided by the invention is alkali-free, chlorine-free, fluorine-free, environment-friendly and excellent in accelerating effect, can obviously shorten the setting time of cement paste, greatly improves the early strength of sprayed concrete, and has high later strength retention rate, and when the doping amount of the accelerator is 7-9%, all properties of the accelerator meet the requirements of GB/T35159 and 2017 accelerator for sprayed concrete on alkali-free liquid accelerators.
Description
Technical Field
The invention belongs to the technical field of concrete using organic materials as effective components of mortar, concrete or artificial stone, and relates to an alkali-free liquid accelerator based on ultrafine limestone suspension polyaluminium sulfate and a preparation method thereof.
Background
The liquid accelerator can promote the cement or concrete to be quickly coagulated and hardened, can produce an additive with certain strength in a short time, and has wide application in the aspects of mines, tunnels, plugging and rush-repair projects and the like. At present, the alkali-free accelerator is mainly a hydrofluoric acid (HF) and sodium fluoride (NaF) system, and a product contains a large amount of fluoride ions, so that on one hand, the alkali-free accelerator is easy to corrode equipment and threatens the physical health of workers. The alkali-free liquid accelerator can ensure the safety of industrial production and the efficient and rapid implementation of construction engineering, and becomes the mainstream direction of the research and development of accelerators. However, the alkali-free liquid accelerator still has some disadvantages in terms of preparation process, cost, performance stability, and the like.
At present, the alkali-free accelerator is usually prepared by a hydrothermal synthesis method, and has the defects of complex synthesis process and severe parameter control; in order to improve the solubility of aluminum sulfate to obtain high quick setting performance and inhibit the hydrolysis of the aluminum sulfate to improve the stability of products, high-concentration raw materials such as fluorosilicate, organic acid and the like are added, so that the price is high, and potential safety hazards exist (CN110078406A, CN107651874A and the like); in addition, accelerator performance is very sensitive to reactant dosage, and improper dosage can result in reduced product performance stability.
In addition, the alkali-free liquid accelerator synthesized by hydrothermal method has contradiction between accelerating efficiency and stability and adaptability. In the prior alkali-free setting accelerators which are prepared by a hydrothermal synthesis method and mainly comprise aluminum sulfate, the setting accelerating effect of the setting accelerator is closely related to the concentration of aluminum ions, and generally, higher aluminum ion concentration means higher setting accelerating performance. However, when the concentration of the dissolved aluminum ions in the accelerator is higher, the accelerator is more easily hydrolyzed to generate aluminum hydroxide flocculent precipitates, and the stability of the product is reduced, so that the requirements of the current national standard GB/T35159-.
Disclosure of Invention
In view of the above, the invention aims to provide an alkali-free liquid accelerator based on ultrafine limestone suspension polyaluminium sulfate and a preparation method thereof, so as to solve the problems of complex process, harsh conditions and sensitive parameters existing in the conventional hydrothermal synthesis method of an alkali-free accelerator, and the problems that the accelerating effect, the adaptability and the stability of the synthesized alkali-free accelerator cannot be simultaneously considered, and provide a brand new technical thought and scheme for the preparation of the alkali-free accelerator.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the invention aims to provide an alkali-free liquid accelerator based on superfine limestone suspension polyaluminium sulfate, which comprises the following raw materials in percentage by mass: 55-61% of polymeric aluminum sulfate octadecahydrate, 9.7-10.7% of light limestone powder, 0.6-1.1% of organic alkali, 0.8-2.2% of polycarboxylic acid water reducing agent, 0.5-0.8% of thickening agent and 24.2-33.4% of water.
According to the scheme, the light limestone powder is industrial light calcium carbonate powder, the purity of calcium carbonate is more than 98% (mass percent), and the particle size of the powder is more than or equal to 1000 meshes. The light calcium carbonate is used as a suspending agent, has a looser structure and is easier to grind compared with heavy calcium carbonate, and the ground calcium carbonate particles can improve the viscosity of the accelerating agent slurry, so that amorphous aluminum sulfate particles in the accelerating agent product can be suspended more stably, and the storage stability of the product is improved.
According to the scheme, the organic alkali is a mixture of ethylenediamine and triethanolamine, and the mass ratio of the organic alkali to the triethanolamine is 1: 0.5-1. The organic alkali can complex aluminum ions and improve the supersaturation degree of the aluminum sulfate aqueous solution. Experiments show that the coordination capacity of the ethylenediamine, the triethanolamine and the aluminum is stronger than that of organic alkali such as monoethanolamine, diethanolamine and the like, and the solubility of aluminum ions can be improved to a greater extent.
According to the scheme, the thickening agent is amide modified polyacrylic acid, the number average molecular weight of the thickening agent is 10000-30000, and the molecular structural formula is as follows:
wherein m: n is 1: 1-3.
The second purpose of the invention is to provide a preparation method of the alkali-free liquid accelerator based on the ultrafine limestone suspension polyaluminum sulfate.
A preparation method of an alkali-free liquid accelerator based on superfine limestone suspension polyaluminium sulfate comprises the following steps:
1) weighing the raw materials in proportion for later use;
2) and (2) putting the polymeric aluminum sulfate octadecahydrate, the light limestone powder, the organic alkali, the polycarboxylic acid water reducing agent, the thickening agent and water into a stainless steel reaction kettle according to the proportion, then adding a stainless steel ball into the stainless steel reaction kettle, stirring for 2-3h, and filtering to remove solid impurities after stirring to obtain the alkali-free liquid accelerator.
According to the scheme, the diameter of the stainless steel ball in the step 2) is 1-5cm, and the mass of the stainless steel ball is equal to the sum of the mass of the polymeric aluminum sulfate octadecahydrate and the mass of the light limestone powder. The function of adding the stainless steel ball lies in utilizing the steel ball collision to refine calcium carbonate and aluminum sulfate in the stirring process, improves thick liquid viscosity, and stirring in-process alcohol amine can take place coordination complex reaction with aluminium ion moreover, improves the aluminum sulfate degree of supersaturation, can also produce the crystal nucleus defect, generates amorphous high activity aluminium sulfate particle.
The third purpose of the invention is to provide a use method of the alkali-free liquid accelerator based on the ultrafine limestone suspension polyaluminium sulfate, wherein when the alkali-free liquid accelerator is applied to sprayed concrete, the dosage of the alkali-free liquid accelerator is 7-9% of the dosage of cement in the sprayed concrete.
Compared with the prior art, the alkali-free liquid accelerator based on the ultrafine limestone suspension polyaluminium sulfate has the following advantages:
1. the alkali-free liquid accelerator provided by the invention is alkali-free, chlorine-free, fluorine-free, environment-friendly and excellent in accelerating effect, can obviously shorten the setting time of cement paste, greatly improves the early strength of sprayed concrete, and has higher later strength retention rate; when the mixing amount of the accelerator is 7-9% (relative to the amount of cement in sprayed concrete), all the performances of the accelerator meet the requirements of GB/T35159 and 2017 accelerator for sprayed concrete on alkali-free liquid accelerators.
2. The invention innovatively adopts a technical means of mechanical force and chemical intervention synergy to prepare the alkali-free liquid accelerator simultaneously containing ultrahigh active particles and ultrahigh saturation liquid phase; in addition, various modifiers such as organic alkali, polycarboxylic acid water reducing agent, thickening agent and the like are added into the liquid phase, so that the solubility of the aluminum sulfate in the liquid phase can be greatly increased, and the suspension stability and particle dispersibility of the accelerator can be obviously improved.
Drawings
FIG. 1 is a graph showing a distribution of particle diameters of solid phase particles before and after agitation in a system according to example 1 of the present invention;
FIG. 2 is a graph showing a comparison of the concentration of aluminum ions in the liquid phase in the system before and after stirring in example 1.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention is further described in detail with reference to the following examples.
The thickener used in the embodiment of the invention is amide modified polyacrylic acid, the number average molecular weight of the thickener is 20000, and the molecular structural formula is as follows:
wherein m: n is 1: 2.
Examples 1 to 9
The proportions of the raw material components in the alkali-free liquid accelerator of examples 1 to 9 of the present invention are shown in Table 1.
Table 1 raw material composition ratio
The alkali-free liquid setting accelerators of examples 1-9 were prepared by the following method, including the steps of:
firstly, weighing raw material components according to a raw material ratio, then putting the weighed polymeric aluminum sulfate octadecahydrate, light limestone powder, organic alkali, polycarboxylic acid water reducer, thickener and water into a reaction kettle, then adding stainless steel balls with the diameter of 1-5cm (the mass of the stainless steel balls is equal to the sum of the mass of the polymeric aluminum sulfate octadecahydrate and the light limestone powder), stirring for 2-3h, and filtering to remove solid impurities to obtain the alkali-free liquid accelerator.
The diameter of the stainless steel balls used in the examples and the stirring time are shown in Table 2.
TABLE 2 basic parameters of the preparation Process
The particle size distribution of the solid phase particles in the system of example 1 before and after stirring was measured by a laser particle sizer, and the result is shown in FIG. 1, wherein D (50) of the solid phase particles was reduced from 8.1 μm to 2.3 μm after stirring for 2-3 h; the liquid phase aluminum ion concentration before and after stirring in example 1 was measured using Inductively Coupled Plasma (ICP) and the results are shown in FIG. 2, where the liquid phase aluminum ion concentration increased from 65mg/L to 185mg/L after stirring, indicating that an alkali-free accelerator comprising ultra-high active fine particles and an ultra-high saturation liquid phase can be prepared by a mechanical and chemical synergistic method.
The stability, the accelerating performance and the early strength performance of the alkali-free liquid accelerator in examples 1-9 are tested according to the requirement standard of GB/T35159 and 2017 accelerating agent for sprayed concrete, wherein the using amount of the alkali-free liquid accelerator is 8% of the mass of the cement, and the test results are shown in Table 3.
TABLE 3 alkali-free liquid Accelerator Performance test results
As can be seen from the performance test data of the alkali-free liquid accelerator shown in Table 3, the alkali-free liquid accelerator prepared by the embodiment of the invention has good stability, and the 28d precipitation volume is less than or equal to 2.5 mL; in addition, the initial setting time of the accelerator-doped neat paste is less than or equal to 5min, and the final setting time is less than or equal to 12 min; the 1d compressive strength of the alkali-free liquid accelerator is more than or equal to 7.0MPa, the early strength reaches the national standard, and the 28d strength retention rate of the cement paste is more than 100% after the alkali-free liquid accelerator is doped, which indicates that the alkali-free liquid accelerator has a certain reinforcing effect on the later strength of concrete. Therefore, the stability, the coagulation accelerating performance and the early strength performance of the alkali-free liquid accelerator prepared by the invention meet the requirements of GB/T35159 and 2017 accelerator for sprayed concrete.
It should be noted that the application range of the present invention is not limited to the construction of shotcrete, and the present invention is also applicable to other materials having requirements for quick setting or early strength.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. An alkali-free liquid accelerator based on superfine limestone suspension polyaluminium sulfate is characterized by comprising the following raw materials in percentage by mass: 55-61% of polymeric aluminum sulfate octadecahydrate, 9.7-10.7% of light limestone powder, 0.6-1.1% of organic alkali, 0.8-2.2% of polycarboxylic acid water reducing agent, 0.5-0.8% of thickening agent and 24.2-33.4% of water.
2. The alkali-free liquid accelerator based on the ultrafine limestone suspension polyaluminium sulfate as claimed in claim 1, wherein the light limestone powder is industrial light calcium carbonate powder, the purity of calcium carbonate is more than 98%, and the particle size mesh number of powder is more than or equal to 1000 meshes.
3. The alkali-free liquid accelerator based on superfine limestone suspension polyaluminium sulfate as claimed in claim 1, wherein the organic base is a mixture of ethylenediamine and triethanolamine, and the mass ratio of the organic base to the triethanolamine is 1: 0.5-1.
4. The alkali-free liquid accelerator based on ultra-fine limestone suspension polyaluminium sulfate as claimed in claim 1, wherein the thickener is an amide modified polyacrylic acid having a number average molecular weight of 10000-30000 and a molecular structural formula as follows:
wherein m: n is 1: 1-3.
5. A method for preparing the alkali-free liquid accelerator based on ultra-fine limestone suspension polyaluminium sulfate as claimed in any one of claims 1 to 4, which comprises the following steps:
1) weighing the raw materials in proportion for later use;
2) and (2) putting the polymeric aluminum sulfate octadecahydrate, the light limestone powder, the organic alkali, the polycarboxylic acid water reducing agent, the thickening agent and water into a stainless steel reaction kettle according to the proportion, then adding a stainless steel ball into the stainless steel reaction kettle, stirring for 2-3h, and filtering to remove solid impurities after stirring to obtain the alkali-free liquid accelerator.
6. The method for preparing the alkali-free liquid accelerator based on ultrafine limestone suspension polyaluminium sulfate according to claim 5, wherein the diameter of the stainless steel ball in the step 2) is 1-5cm, and the mass of the stainless steel ball is equal to the sum of the mass of the octadecylic polyaluminium sulfate and the mass of the light limestone powder.
7. The method for using the alkali-free liquid accelerator based on ultrafine limestone suspension polyaluminium sulfate as claimed in any one of claims 1 to 4, wherein the alkali-free liquid accelerator is added in an amount of 7 to 9% of the amount of cement in the shotcrete when the alkali-free liquid accelerator is applied to the shotcrete.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014152058A (en) * | 2013-02-06 | 2014-08-25 | Denki Kagaku Kogyo Kk | Liquid quick setting agent, cement composition using the same, and spraying method |
| CN109734354A (en) * | 2019-02-20 | 2019-05-10 | 赵兴华 | A kind of preparation method of concrete liquid accelerator |
| CN110922085A (en) * | 2019-12-16 | 2020-03-27 | 武汉优城科技有限公司 | Aluminum sulfate supersaturated suspension type alkali-free liquid accelerator and preparation method thereof |
| CN112194408A (en) * | 2020-11-05 | 2021-01-08 | 山东正珩新材料科技有限责任公司 | Liquid alkali-free accelerator and preparation method thereof |
| CN112707665A (en) * | 2019-11-19 | 2021-04-27 | 陕西科之杰新材料有限公司 | Aluminum sulfate alkali-free liquid accelerator and preparation method thereof |
| CN112939511A (en) * | 2021-04-08 | 2021-06-11 | 陈森章 | Alkali-free liquid accelerator |
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- 2021-11-22 CN CN202111388613.3A patent/CN114031326B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014152058A (en) * | 2013-02-06 | 2014-08-25 | Denki Kagaku Kogyo Kk | Liquid quick setting agent, cement composition using the same, and spraying method |
| CN109734354A (en) * | 2019-02-20 | 2019-05-10 | 赵兴华 | A kind of preparation method of concrete liquid accelerator |
| CN112707665A (en) * | 2019-11-19 | 2021-04-27 | 陕西科之杰新材料有限公司 | Aluminum sulfate alkali-free liquid accelerator and preparation method thereof |
| CN110922085A (en) * | 2019-12-16 | 2020-03-27 | 武汉优城科技有限公司 | Aluminum sulfate supersaturated suspension type alkali-free liquid accelerator and preparation method thereof |
| CN112194408A (en) * | 2020-11-05 | 2021-01-08 | 山东正珩新材料科技有限责任公司 | Liquid alkali-free accelerator and preparation method thereof |
| CN112939511A (en) * | 2021-04-08 | 2021-06-11 | 陈森章 | Alkali-free liquid accelerator |
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