High-strength super-retarding super-sulfate cement material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of low-carbon building materials, and particularly discloses a high-strength super-retarding super-sulfate cement material as well as a preparation method and application thereof. The cement material comprises the following raw materials in parts by weight: 75-85 parts of a slag gelling component, 10-20 parts of gypsum, 0.5-5 parts of an alkali activator, 1-5 parts of a composite retarder, 0.35-1 part of a water reducing agent and 0.2-1 part of a defoaming agent. Wherein the composite retarder is prepared from the following components in parts by weight: 2-3 parts of fluosilicate, 8-10 parts of sulphoaluminate cement and ferric sulfate, and the content of the ferric sulfate is 1.2-1.5 times that of the fluosilicate. The composite retarder disclosed by the invention not only has better stability, but also can effectively prolong the setting time of the super-sulfate cement material in a high-temperature environment, and greatly improves the mechanical strength of the super-sulfate cement material in the whole age.

Description

Technical Field

[0001] This invention relates to the field of low-carbon building materials technology, specifically to a high-strength, ultra-retarded setting supersulfate cement material, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Supersulfate cement (SSC) is a low-carbon cementitious material composed of a small amount of cement clinker and a large amount of industrial byproducts such as gypsum and slag. It is characterized by its simple preparation, environmental friendliness, low energy consumption, and good resistance to sulfate attack. Replacing traditional silicate cement with supersulfate cement helps reduce carbon emissions and is an effective means of achieving a green transformation in the cement industry. Due to its slower hydration and hardening rate, supersulfate cement is more suitable for applications in deep well solidification and deep well backfilling compared to silicate cement and sulfoaluminate cement. This is because cementing operations require pumping cement slurry to the bottom of the well and back through the annulus to the predetermined depth, which typically takes a considerable amount of time. During this period, the cement slurry must maintain good flowability. However, increased downhole temperature significantly accelerates the cement hydration reaction, causing the cement slurry to solidify in a shorter time. If the cement slurry solidifies before reaching the target location, it can clog the wellbore or delivery pump, leading to cementing failure.

[0004] While adding retarders (such as lignin sulfonates, hydroxycarboxylic acids, organophosphonates, cellulose derivatives, and carbohydrate compounds) can extend the setting time of hypersulfate cement, these traditional retarders typically only function effectively at room temperature. In the special environment of deep wells, the high temperature and pressure can significantly reduce their retarding effect, or even render them ineffective. Furthermore, the addition of retarders can decrease the mechanical strength of cement materials. Some retarders (such as citric acid and borax) can adsorb onto the surface of slag particles, forming a semi-permeable or impermeable layer that hinders the contact between slag particles and water, inhibits slag hydration, and reduces the amount of cementitious products generated. In addition, alkali-activated components in hypersulfate cement (such as...) , The supersulfate cement interacts with the retarder, negating its retarding effect. Therefore, exploring supersulfate cement suitable for deep well scenarios is key to its engineering application. Summary of the Invention

[0005] In order to solve the above problems, the application provides a high-strength super-retarding super-sulfate cement material and a preparation method and application thereof. The composite retarder has better stability, can effectively improve the setting time of the super-sulfate cement material in a high-temperature environment, and greatly improves the mechanical strength of the super-sulfate cement material in the whole age period. Specifically, the technical method of the application is as follows.

[0006] Firstly, the application provides a high-strength super-retarding super-sulfate cement material, which comprises raw materials in the following proportions: 75-85 parts by weight of a slag cementitious component, 10-20 parts by weight of gypsum, 0.5-5 parts by weight of an alkaline activator, 1-5 parts by weight of a composite retarder, 0.35-1 part by weight of a water reducing agent, and 0.2-1 part by weight of a defoaming agent. The composite retarder is composed of components in the following proportions: 2-3 parts by weight of a fluorosilicate, 8-10 parts by weight of a sulphoaluminate cement, and iron sulfate, wherein the content of the iron sulfate is 1.2-1.5 times that of the fluorosilicate.

[0007] Further, the fluorosilicate comprises at least one of sodium fluorosilicate, potassium fluorosilicate, etc.

[0008] Further, the slag cementitious component comprises mineral powder and fly ash. Alternatively, the proportion of the mineral powder and the fly ash is 7-8 parts by weight: 0.5-1.5 parts by weight.

[0009] Further, the gypsum comprises at least one of phosphogypsum, hemihydrate gypsum, dihydrate gypsum, etc.

[0010] Further, the alkaline activator comprises at least one of calcium hydroxide, potassium hydroxide, ordinary Portland cement, etc.

[0011] Further, the water reducing agent comprises at least one of a polycarboxylic acid water reducing agent, a naphthalene water reducing agent, a lignin sulfonate water reducing agent, etc.

[0012] Further, the defoaming agent comprises at least one of an organic silicon defoaming agent, a polyether defoaming agent, a non-silicon defoaming agent, etc.

[0013] Further, the raw materials further comprise 18-30 parts by weight of mixing water.

[0014] Secondly, the application provides a preparation method of the high-strength super-retarding super-sulfate cement material, which comprises the following steps: (1) The slag cementitious component, the gypsum and the alkaline activator are mixed and ground to obtain a mixed powder.

[0015] (2) The mixed powder is uniformly mixed with the composite retarder, and then the water reducing agent and the defoaming agent are added and uniformly mixed.

[0016] Further, in step (1), the specific surface area of ​​the mixed powder is ≥400m². 2 / kg.

[0017] Furthermore, step (2) also includes the step of adding mixing water. Optionally, the water-reducing agent, defoamer, and mixing water are added together.

[0018] Finally, this invention provides the application of the high-strength, ultra-retarded, supersulfate cement material in deep well solidification, deep well underground filling, and other engineering projects.

[0019] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: This invention utilizes a composite retarder composed of fluorosilicate, sulfoaluminate cement, and ferric sulfate to not only improve the setting time of hypersulfate cement materials under high-temperature conditions but also significantly enhance their mechanical strength throughout their entire lifespan. This is because, on the one hand, some of the fluorosilicates hydrolyze in the alkaline environment provided by the alkaline activator (…). )release It combines with calcium ions released from the surface of the slag cementitious components and sulfoaluminate cement particles to form a calcium fluoride coating layer, reducing the contact between the slag cementitious components and sulfoaluminate cement and water, thereby delaying their hydration reaction and increasing the time required for solidification and hardening. Simultaneously, due to the better thermal stability of the calcium fluoride coating layer, it can prevent decomposition and failure during transportation. On the other hand, another portion of the fluorosilicate reacts with ferric sulfate in an alkaline environment provided by an alkaline activator (…). ), forming complexes The coating on the surface of the slag cementitious components and sulfoaluminate cement particles also helps to slow down their hydration reaction rate. Additionally, the ferric sulfate and the slag cementitious components released during the early hydration process... The reaction forms ferric hydroxide (Fe(OH)2) Colloidal substances, which adsorb and coat the surface of slag cementitious components, also slow down the hydration process.

[0020] Once the supersulfate cement material is delivered, the calcium fluoride and complexes on the surface of the slag cementitious particles and sulfoaluminate cement particles... Under the combined effects of high temperature and alkaline conditions, it gradually begins to decompose. This allows the slag cementitious components and sulfoaluminate cement to come into more complete contact with water, accelerating hydration. On the one hand, the calcium fluoride decomposes and releases... As a highly efficient nucleating agent, it provides numerous nucleation sites for the precipitation of hydration products, while simultaneously releasing... The above processes can promote the formation of the hydrated cementitious product. Meanwhile, the hydration of the sulphoaluminate cement can quickly build up the support skeleton to provide good early strength for the cementitious material. On the other hand, the fluorosilicate reacts with the ferric sulfate to form calcium hydroxide, the hydration product of the slag cementitious component, to further form calcium silicate hydrate , which also contributes to the improvement of the mechanical strength of the cementitious material. The can effectively supplement the sulfate required for the formation of the ettringite, the hydration reaction product, to prevent the formation of flaky monosulfate type hydrated calcium sulphoaluminate in the early stage of hydration due to the insufficient sulfate provided by the gypsum, which has much weaker interlocking ability between the crystals than ettringite, affecting the early mechanical strength of the cementitious material. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of the present description, illustrate the present application and, together with the written description, serve to explain the application. In the drawings:

[0022] Figure 1 Sample chart of the composite retarder of Example 1 below.

[0023] Figure 2 Setting time test chart of Example 1 below.

[0024] Figure 3 Compressive strength test chart of Example 1 below.

[0025] Figure 4 Flexural strength test chart of Example 1 below.

[0026] Figure 5 Sample chart of the composite retarder of Example 2 below.

[0027] Figure 6 Setting time test chart of Example 2 below.

[0028] Figure 7 Sample chart of the composite retarder of Example 3 below. DETAILED DESCRIPTION

[0029] The application will be further described with reference to the following examples. It should be understood that these examples are intended to illustrate the application and are not intended to limit the scope of the application. The experimental methods in the following examples, if not specified, are usually carried out under the conventional conditions or under the conditions recommended by the manufacturers.

[0030] ​Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or materials used in the present application can be purchased through conventional routes, and unless otherwise specified, the reagents or materials used in the present application are used according to the conventional manner in the art or according to the product instructions.

[0031] In addition, any method and material similar or equivalent to the described content can be applied to the method of the present application. The technical solutions of the present application are further described in conjunction with the drawings and specific embodiments of the present application.

[0032] Example 1: A method for preparing a high-strength super-delayed-setting super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementing component 80 parts by weight, gypsum (phosphogypsum powder) 15 parts by weight, alkaline activator (potassium hydroxide) 3 parts by weight, composite retarder 2.5 parts by weight, polycarboxylic acid water reducer 0.6 parts by weight, organic silicon defoaming agent 0.7 parts by weight, and mixing water 25 parts by weight. Among them, the slag cementing component is composed of S95 mineral powder and grade II fly ash in a ratio of 8 parts by weight: 1.5 parts by weight. The composite retarder is composed of sodium fluorosilicate, sulphoaluminate cement, and ferric sulfate in a ratio of 2.4 parts by weight: 11 parts by weight: 3.2 parts by weight (as shown in Figure 1 ).

[0033] (2) First, mix the slag cementing component, gypsum, and alkaline activator, then use a ball mill for ball milling, to obtain a mixed powder with a specific surface area of 457.4 m 2 / kg, ready for use.

[0034] (3) Mix the mixed powder with the composite retarder and stir for 3 min, then add the water reducer, defoaming agent, and mixing water and continue stirring for 2 min to obtain a super-sulfate cement material.

[0035] Performance test: 1. The setting time of the super-sulfate cement material prepared in this embodiment was tested using a Vicat instrument (model SNCD-70) (as shown in Figure 2 ). 2. The early mechanical strength (including 3d compressive strength and 3d flexural strength, respectively as shown in Figure 3 , Figure 4 ) of the super-sulfate cement material prepared in this embodiment was tested according to the standard GB / T 17671-2021 "Cement mortar strength test method (IOS method)", and the results are shown in Table 1 below.

[0036] Table 1 Test results

[0037] Embodiment 2: A preparation method of a high-strength super-delayed-setting super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 85 parts by weight, gypsum (hemihydrate gypsum powder) 20 parts by weight, alkaline activator (42.5 ordinary Portland cement powder) 5 parts by weight, composite retarder 5 parts by weight, polycarboxylic acid water reducer 1 part by weight, polyether defoaming agent 1 part by weight, and mixing water 18 parts by weight. Among them, the slag cementitious component is composed of S95 mineral powder and grade II fly ash in a proportion of 7 parts by weight: 1 part by weight. The composite retarder is composed of sodium fluorosilicate, sulphoaluminate cement, and ferric sulfate in a proportion of 3 parts by weight: 10 parts by weight: 4.5 parts by weight (as shown in Figure 5 ).

[0038] (2) First, mix the slag cementitious component, gypsum, and alkaline activator, then use a ball mill for ball milling, to obtain a mixed powder with a specific surface area of 401.8 m 2 / kg, for standby use.

[0039] (3) Mix the mixed powder with the composite retarder and stir for 3 minutes, then add the water reducer, defoaming agent, and mixing water and continue to stir for 2 minutes, to obtain a super-sulfate cement material.

[0040] Performance test: The setting time (as shown in Figure 6 ), 3d compressive strength, and 3d flexural strength of the super-sulfate cement material prepared in this embodiment were tested by the same method as in Embodiment 1, and the results are shown in Table 2.

[0041] Table 2 Test results

[0042] Embodiment 3: A preparation method of a high-strength super-delayed-setting super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 75 parts by weight, gypsum (dihydrate gypsum) 10 parts by weight, alkaline activator (calcium hydroxide) 0.5 parts by weight, composite retarder 1 part by weight, sodium lignosulfonate water reducer 0.35 parts by weight, polyether defoaming agent 0.2 parts by weight, and mixing water 30 parts by weight. Among them, the slag cementitious component is composed of S95 mineral powder and grade II fly ash in a proportion of 7.3 parts by weight: 0.5 parts by weight. The composite retarder is composed of potassium fluorosilicate, sulphoaluminate cement, and ferric sulfate in a proportion of 2 parts by weight: 8 parts by weight: 2.4 parts by weight (as shown in Figure 7 ).

[0043] (2) First, mix the slag cementitious component, gypsum, and alkaline activator, then use a ball mill for ball milling, to obtain a mixed powder with a specific surface area of 477.1 m 2 / kg, for standby use.

[0044] (3) The mixed powder is mixed with the composite retarder for 3 min, then the water reducing agent, defoaming agent and mixing water are added and stirred for 2 min, to obtain the super-sulfate cement material.

[0045] Performance test: The setting time and 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example are tested by the same method as in Example 1, and the results are shown in Table 3 below.

[0046] Table 3 Test results

[0047] Example 4: A method for preparing a high-strength super-retarded super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementing component 80 parts by weight, gypsum (phosphogypsum powder) 15 parts by weight, alkaline activator (potassium hydroxide) 3 parts by weight, retarder (borax) 2.5 parts by weight, polycarboxylic acid water reducer 0.6 parts by weight, organic silicon defoaming agent 0.7 parts by weight, and mixing water 25 parts by weight. Among them, the slag cementing component is composed of S95 mineral powder and grade II fly ash in a ratio of 8 parts by weight: 1.5 parts by weight.

[0048] (2) First, the slag cementing component, gypsum and alkaline activator are mixed and ball milled by a ball mill to obtain a mixed powder with a specific surface area of 457.4 m 2 / kg, ready for use.

[0049] (3) The mixed powder is mixed with the retarder for 3 min, then the water reducing agent, defoaming agent and mixing water are added and stirred for 2 min, to obtain the super-sulfate cement material.

[0050] Performance test: The setting time and 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example are tested by the same method as in Example 1, and the results are shown in Table 4 below.

[0051] Table 4 Test results

[0052] Example 5: A method for preparing a high-strength super-retarded super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 80 parts by weight, gypsum (phosphogypsum powder) 15 parts by weight, alkaline activator (potassium hydroxide) 3 parts by weight, retarder (citric acid) 2.5 parts by weight, polycarboxylic acid water reducer 0.6 parts by weight, organic silicon defoaming agent 0.7 parts by weight, and mixing water 25 parts by weight. Among them, the slag cementitious component is composed of S95 mineral powder and grade II fly ash in a ratio of 8 parts by weight: 1.5 parts by weight.

[0053] (2) First, the slag cementitious component, gypsum, and alkaline activator are mixed and then ball milled using a ball mill to obtain a mixed powder with a specific surface area of 457.4 m 2 / kg, ready for use.

[0054] (3) The mixed powder is mixed with the retarder and stirred for 3 min, then the water reducer, defoaming agent, and mixing water are added and continue to stir for 2 min to obtain the super-sulfate cement material.

[0055] Performance test: The setting time and 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example are tested by the same method as in Example 1 above, and the results are shown in Table 5 below.

[0056] Table 5 Test results

[0057] Example 6: A method for preparing a high-strength super-retarded super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 85 parts by weight, gypsum (semi-hydrated gypsum powder) 20 parts by weight, alkaline activator (42.5 ordinary portland cement powder) 5 parts by weight, composite retarder 5 parts by weight, polycarboxylic acid water reducer 1 part by weight, polyether defoaming agent 1 part by weight, and mixing water 18 parts by weight. Among them, the slag cementitious component is composed of S95 mineral powder and grade II fly ash in a ratio of 7 parts by weight: 1 part by weight. The composite retarder is composed of sulphoaluminate cement and iron sulfate in a ratio of 10 parts by weight: 4.5 parts by weight.

[0058] (2) First, the slag cementitious component, gypsum, and alkaline activator are mixed and then ball milled using a ball mill to obtain a mixed powder with a specific surface area of 401.8 m 2 / kg, ready for use.

[0059] (3) The mixed powder is mixed with the composite retarder and stirred for 3 min, then the water reducer, defoaming agent, and mixing water are added and continue to stir for 2 min to obtain the super-sulfate cement material.

[0060] Performance test: the setting time, 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example were tested by the same method as that of Example 1, and the results are shown in Table 6 below.

[0061] Table 6 Test results

[0062] Example 7: A method for preparing a high-strength super-delayed-setting super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 75 parts by weight, gypsum (dihydrate gypsum powder) 10 parts by weight, alkaline activator (calcium hydroxide) 0.5 parts by weight, composite retarder 1 part by weight, sodium lignosulfonate water reducer 0.35 parts by weight, polyether defoaming agent 0.2 parts by weight, and mixing water 30 parts by weight. The slag cementitious component is composed of S95 mineral powder and Class II fly ash in a ratio of 7.3 parts by weight: 0.5 parts by weight. The composite retarder is composed of potassium fluosilicate and sulphoaluminate cement in a ratio of 2 parts by weight: 8 parts by weight.

[0063] (2) First, mix the slag cementitious component, gypsum, and alkaline activator, then use a ball mill to ball mill, to obtain a mixed powder with a specific surface area of 477.1 m 2 / kg, ready for use.

[0064] (3) Mix the mixed powder with the composite retarder and stir for 3 minutes, then add the water reducer, defoaming agent, and mixing water and continue stirring for 2 minutes to obtain a super-sulfate cement material.

[0065] Performance test: the setting time, 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example were tested by the same method as that of Example 1, and the results are shown in Table 6 below.

[0066] Table 7 Test results

[0067] Example 8: A method for preparing a high-strength super-delayed-setting super-sulfate cement material, comprising the following steps: (1) Take the following proportions of components: slag cementitious component 80 parts by weight, gypsum (dihydrate gypsum powder) 15 parts by weight, alkaline activator (calcium hydroxide) 3 parts by weight, composite retarder 2.5 parts by weight, polyether defoaming agent 0.6 parts by weight, polyether defoaming agent 0.7 parts by weight, and mixing water 25 parts by weight. The slag cementitious component is composed of S95 mineral powder and Class II fly ash in a ratio of 8 parts by weight: 1.5 parts by weight. The composite retarder is composed of sodium fluosilicate and ferric sulfate in a ratio of 2.4 parts by weight: 3.2 parts by weight.

[0068] (2) The slag cementitious component, gypsum and alkaline activator are mixed and then ball-milled to obtain a mixed powder with a specific surface area of 457.4 m2 / kg. 2

[0069] (3) The mixed powder is mixed with a composite retarder for 3 min, then the water reducing agent, defoaming agent and mixing water are added and stirred for 2 min to obtain the super-sulfate cement material.

[0070] Performance test: The setting time, 3d compressive strength and 3d flexural strength of the super-sulfate cement material prepared in this example are tested by the same method as that in Example 1, and the results are shown in Table 8.

[0071] Table 8 Test results

[0072] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will still be able to make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A high-strength, ultra-retarded, supersulfate cement material, characterized in that, The raw materials include the following proportions: 75-85 parts by weight of slag cementitious component, 10-20 parts by weight of gypsum, 0.5-5 parts by weight of alkaline activator, 1-5 parts by weight of composite retarder, 0.35-1 parts by weight of water-reducing agent, and 0.2-1 parts by weight of defoamer; wherein the composite retarder is composed of the following components in the following proportions: 2-3 parts by weight of fluorosilicate, 8-10 parts by weight of sulfoaluminate cement, and ferric sulfate, wherein the ferric sulfate content is 1.2-1.5 times that of fluorosilicate.

2. The high-strength, ultra-retarded, supersulfate cement material according to claim 1, characterized in that, The fluorosilicate includes at least one of fluorosilicate and potassium fluorosilicate.

3. The high-strength, ultra-retarded, supersulfate cement material according to claim 1, characterized in that, The slag cementitious component includes mineral powder and fly ash; optionally, the ratio of mineral powder to fly ash is 7-8 parts by weight: 0.5-1.5 parts by weight.

4. The high-strength, ultra-retarded, supersulfate cement material according to claim 1, characterized in that, The gypsum includes at least one of phosphogypsum, hemihydrate gypsum, and dihydrate gypsum. Optionally, the alkaline activator includes at least one of calcium hydroxide, potassium hydroxide, and ordinary silicate cement.

5. The high-strength, ultra-retarded, supersulfate cement material according to claim 1, characterized in that, The water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene-based water-reducing agent, and lignin sulfonate water-reducing agent.

6. The high-strength, ultra-retarded, supersulfate cement material according to claim 1, characterized in that, The defoamer includes at least one of the following: silicone defoamer, polyether defoamer, and non-silicone defoamer.

7. The high-strength, ultra-retarded, supersulfate cement material according to any one of claims 1-6, characterized in that, The raw materials also include 18-35 parts by weight of mixing water.

8. The method for preparing the high-strength, ultra-retarded, supersulfate cement material according to any one of claims 1-7, characterized in that, Includes the following steps: (1) The slag cementing components, gypsum, and alkaline activator are mixed and then ground to obtain a mixed powder; (2) Mix the mixed powder with the composite retarder, and then add the water-reducing agent and defoamer and mix well.

9. The method for preparing high-strength, ultra-retarded, supersulfate cement material according to claim 8, characterized in that, In step (1), the specific surface area of ​​the mixed powder is ≥400m². 2 / kg; Optionally, step (2) may also include adding mixing water; optionally, the water-reducing agent, defoamer, and mixing water may be added together.

10. The application of the high-strength, ultra-retarded setting, supersulfate cement material according to any one of claims 1-7 in deep well solidification or deep well underground filling projects.

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