A LC prepared based on ball clay 3 Materials and preparation methods

Abstract

This invention discloses a novel LC based on ball clay. 3 The materials and their preparation method include sintered clay, cement clinker, heavy calcium carbonate powder, and building gypsum powder, which are mixed and ground together. This novel LC... 3 Cementitious materials can increase the replacement rate of ordinary Portland cement, reducing carbon emissions. Simultaneously, high Al2O3 content can effectively improve the high-temperature resistance of this cement material. In addition, LC cement can be prepared by replacing traditional pure kaolin and heavy calcium carbonate powder with low-quality spherical clay as raw material. 3 The new type of cement has the advantages of being widely available and inexpensive. Therefore, this patent invention provides a novel LC cement. 3 Cementitious systems are a new type of building material with excellent mechanical properties, good temperature stability, and both environmental and economic benefits, which have significant benefits for the environment, energy, economy and society.

Description

Technical Field

[0001] This invention discloses a novel LC prepared based on ball clay. 3 The material and its preparation method are for high-temperature building structural components, and the preparation method is also provided, belonging to the field of building materials technology. Background Technology

[0002] Portland cement (PC), as the primary cementing material in concrete production, accounts for 60% of total building energy consumption. Therefore, a low-carbon cement—limestone calcined clay cement (LC)—is needed. 3 It was developed in recent years (International Patent No. EP2253600 A1). LC 3 It is a cementing material composed of limestone, calcined clay, gypsum, and clinker. Due to LC 3 Compared to ordinary Portland cement, it has a higher clinker replacement rate, using LC 3 It can reduce CO2 emissions by about 30%. Using calcined clay and limestone can significantly optimize the pore structure of cementitious materials, reduce porosity, and thus effectively inhibit the diffusion and intrusion of harmful media, improving the concrete's resistance to chloride ion attack. Under the same conditions, the chloride ion diffusion coefficient of the calcined clay and limestone composite cementitious system is lower than that of ordinary Portland cement. Therefore, it is considered a promising new low-carbon cement system. However, currently... 3 The following defects exist: (1) Currently, LC 3 The preparation mainly uses high-purity metakaolin, which has a high cost. (2) At present, the upper limit of the content of calcined clay and limestone is generally 45%~50%. When the content is excessive, the LC 3 Mechanical properties are significantly reduced, (3)LC 3 The high-temperature resistance of the system is worse than that of ordinary silicate cement (Sanchit Gupta, 2022, 4 (29) 263-278). Therefore, how to use abundant mineral clay to replace pure metakaolin, and increase the amount of substitution by controlling its reactivity through chemical composition, while improving the high-temperature resistance, is of great significance for energy conservation and emission reduction of building materials.

[0003] This invention utilizes ball clay (BC), a natural clay mineral primarily composed of disordered kaolinite, illite, and quartz, with the general formula Al₂O₃•2SiO₂·2H₂O. It is defined as a highly plastic, fine-grained clay suitable for rheological processes. After calcination, the high kaolinite content in the ball clay transforms into metakaolinite, exhibiting high pozzolanic activity. The active SiO₂ and Al₂O₃ react chemically with the hydration product Ca(OH)₂ in the PC hydration system, forming a CASH colloidal cross-linked structure. This achieves a denser microstructure than CSH, enabling LC... 3 It has good mechanical strength and is particularly resistant to Cl. - Ion erosion. More importantly, ball clay has a high Al2O3 / SiO2 ratio and low content of fusible components such as K and Na oxides, thus exhibiting high refractoriness and outstanding high-temperature resistance. Excellent pozzolanic activity and high-temperature resistance distinguish ball clay from other calcined clays. Therefore, it has great application potential as a structural component for high-temperature furnaces or high-rise buildings.

[0004] This patent uses unprocessed heavy calcium carbonate powder instead of limestone, which has better flowability and dispersibility compared to light calcium carbonate powder. Good flowability avoids the drawback of reduced flowability caused by adding calcined clay to the concrete system; better dispersibility leads to better reactivity of volcanic ash in the clay with CaCO3, resulting in the formation of more stable hemi-aluminate and mono-aluminate. In particular, the heavy calcium carbonate powder used in this invention has a fineness between 400 and 600 mesh; smaller particle size is more beneficial to improving refractoriness. Therefore, heavy calcium carbonate powder is a highly active and more economical limestone substitute, which not only reduces production costs but also increases the toughness and strength of the product, while synergistically reinforcing the novel LC with clay. 3 High temperature resistance.

[0005] In summary, this patent utilizes calcined clay and heavy calcium carbonate powder as raw materials to invent a novel LC method. 3 Cementitious systems are a new type of building material with excellent mechanical properties, good temperature stability, and both environmental and economic benefits. Summary of the Invention

[0006] The technical problem to be solved:

[0007] 1. This invention provides a novel LC based on ball clay. 3 The material lies in further increasing the amount of cement clinker that can be replaced.

[0008] 2. This invention provides a novel LC based on ball clay. 3 Materials, in solving LC 3 The material has poor high-temperature resistance compared to ordinary silicate cement.

[0009] 3. This invention provides a novel LC based on ball clay. 3 The material lies in solving the problems of traditional LC. 3 The issue is that the calcined clay in the material can only be pure metakaolin.

[0010] 4. This invention provides a novel LC based on ball clay. 3 The goal is to further reduce production costs and energy consumption.

[0011] Technical solution

[0012] To achieve the above technical requirements, this invention provides a novel LC based on spherical clay. 3 The material and its preparation method can replace ordinary silicate cement and limestone-calcined clay cement and other cement-based cementitious materials, possessing excellent mechanical strength, high-temperature resistance, and impermeability. This is achieved through the following technical solution:

[0013] A novel LC prepared based on ball clay 3 The material is composed of the following components: calcined clay balls, cement clinker, heavy calcium carbonate powder, and building gypsum powder.

[0014] (1) Preferably, the chemical composition Al2O3 / SiO2 value of the calcined ball clay is between 0.5 and 0.7.

[0015] (2) Preferably, the heavy calcium carbonate powder has a fineness between 400 and 600 mesh and a CaCO3 content between 95 and 98.5%.

[0016] (3) Preferably, the particle size of the building gypsum powder is between 40 and 100 μm.

[0017] (4) Preferably, the novel high-temperature resistant LC 3 The specific proportions of each component of the material are as follows: 30-40 parts of ball clay, 32-47 parts of cement clinker, 10-15 parts of heavy calcium carbonate powder, and 3-8 parts of building gypsum powder.

[0018] Preparation method:

[0019] A novel LC prepared based on ball clay 3 The material preparation method, specifically the following steps:

[0020] (1) Calcine the original clay ball at 650~750℃.

[0021] (2) Weigh out the calcined clay balls, cement clinker, heavy calcium carbonate powder and gypsum according to the proportion, mix them thoroughly and grind them until the specific surface area reaches 300-400 m². 2 / kg.

[0022] The positive effects of this invention:

[0023] Compared with the prior art, the present invention provides a novel LC based on ball clay. 3 The positive effects of the materials and their preparation methods are as follows:

[0024] 1. LC prepared using ball clay 3 The fire resistance and mechanical properties of cement have been improved.

[0025] 2. Using calcined natural clay balls instead of calcined pure kaolin reduces costs and energy consumption.

[0026] 3. The high pozzolanic activity of calcined clay balls increases the amount of cement clinker that can be replaced.

[0027] 4. The preparation process of this new material is simple, it makes good use of waste and is environmentally friendly, and it has significant social benefits. Detailed Implementation

[0028] The present invention is further illustrated by the following embodiments, which are not intended to limit the invention in any way. Any modifications or alterations made to the present invention that are easily implemented by those skilled in the art without departing from the technical solutions of the present invention shall fall within the scope of the claims of the present invention.

[0029] Example 1:

[0030] The raw clay was calcined at 700℃. Calcined clay, cement clinker, heavy calcium carbonate powder, and gypsum were weighed out in a ratio of 30 parts:50 parts:15 parts:5 parts and thoroughly mixed. The mixture was then ground until the specific surface area reached 300–400 m². 2 / kg, then 450g of composite cementitious material was mixed with 1350g of standard sand, and 225g of deionized water was added at a water-cement ratio of 0.5 to prepare LC. 3 Mortar test blocks were cured for 28 days for strength property determination; simultaneously, the LC... 3 Cement is a binder material. The design of C30 grade concrete involves determining the LC (cementing capacity) through mix design. 3 In addition to the amount of aggregate used, specimens with dimensions of 100 × 100 × 100 mm and Φ100 × 50 mm were prepared and cured for 28 days for high temperature resistance and electrical flux tests, respectively.

[0031] Implementation: 2:

[0032] The raw clay was calcined at 600℃. Calcined clay, cement clinker, heavy calcium carbonate powder, and gypsum were weighed out in a ratio of 40 parts:40 parts:15 parts:5 parts, thoroughly mixed, and then ground until the specific surface area reached 300–400 m². 2 / kg, then 450g of composite cementitious material was mixed with 1350g of standard sand, and 225g of deionized water was added at a water-cement ratio of 0.5 to prepare LC. 3 Mortar test blocks were cured for 28 days for strength property determination; simultaneously, the LC... 3 Cement is a cementitious material. The mix design is based on C30 grade concrete to determine the LC (cementing capacity). 3 In addition to the amount of aggregate used, specimens with dimensions of 100 × 100 × 100 mm and Φ100 × 50 mm were prepared and cured for 28 days for high temperature resistance and electrical flux tests, respectively.

[0033] Implementation: 3:

[0034] The raw clay was calcined at 700℃. Calcined clay, cement clinker, heavy calcium carbonate powder, and gypsum were weighed out in a ratio of 35 parts:45 parts:15 parts:5 parts, thoroughly mixed, and then ground until the specific surface area reached 300–400 m². 2 / kg, then 450g of composite cementitious material was mixed with 1350g of standard sand, and 225g of deionized water was added at a water-cement ratio of 0.5 to prepare LC. 3 Mortar test blocks were cured for 28 days for strength property determination; simultaneously, the LC... 3 Cement is a cementitious material. The mix design is based on C30 grade concrete to determine the LC (cementing capacity). 3 In addition to the amount of aggregate used, specimens with dimensions of 100×100×100 mm and Φ100×50 mm were prepared and cured for 28 days for high temperature resistance and electrical flux tests, respectively.

[0035] Example 4:

[0036] The raw clay was calcined at 750℃. Calcined clay, cement clinker, heavy calcium carbonate powder, and gypsum were weighed out in a ratio of 40 parts:40 parts:15 parts:5 parts, thoroughly mixed, and then ground until the specific surface area reached 300–400 m². 2 / kg, then 450g of composite cementitious material was mixed with 1350g of standard sand, and 225g of deionized water was added at a water-cement ratio of 0.5 to prepare LC. 3 Mortar test blocks were cured for 28 days for strength property determination; simultaneously, the LC... 3 Cement is a cementitious material. The mix design is based on C30 grade concrete to determine the LC (cementing capacity). 3 In addition to the amount of aggregate used, specimens with dimensions of 100 × 100 × 100 mm and Φ100 × 50 mm were prepared and cured for 28 days for high temperature resistance and electrical flux tests, respectively.

[0037] Example 5:

[0038] The raw clay was calcined at 700℃. Calcined clay, cement clinker, heavy calcium carbonate powder, and gypsum were weighed out in a ratio of 40 parts: 42 parts: 13 parts: 5 parts, thoroughly mixed, and then ground until the specific surface area reached 300–400 m². 2 / kg, then 450g of composite cementitious material was mixed with 1350g of standard sand, and 225g of deionized water was added at a water-cement ratio of 0.5 to prepare LC. 3 Mortar test blocks were cured for 28 days for strength property determination; simultaneously, the LC... 3 Cement is a cementitious material. The mix design is based on C30 grade concrete to determine the LC (cementing capacity). 3 In addition to the amount of aggregate used, specimens with dimensions of 100 × 100 × 100 mm and Φ100 × 50 mm were prepared and cured for 28 days for high temperature resistance and electrical flux tests, respectively.

[0039] Experimental example:

[0040] The cementitious materials prepared in Examples 1-4 were subjected to strength, chloride ion penetration resistance, and fire resistance tests. Strength testing was conducted according to GB / T 17617-1999, "Test Method for Strength of Cement Mortar (ISO Method)"; chloride ion penetration resistance was determined according to GB / T50082-2009, "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete"; and fire resistance was determined according to ISO 834-1, "Fire-resistance tests - Elements of building construction - Part 1: General requirements". The experimental results are shown in Table 1.

[0041] Table 1 Performance measurements of each embodiment

[0042]

Claims

1. An LC prepared based on ball clay 3 The material is characterized by being It is composed of the following materials in parts by mass: 30-40 parts calcined clay, 32-47 parts cement clinker, 10-15 parts heavy calcium carbonate powder, and 3-8 parts building gypsum powder; wherein the calcined clay contains 62%-65% kaolinite and has an Al2O3 / SiO2 ratio between 0.5 and 0.

7.

2. The LC according to claim 1 3 The material is characterized by: The fineness of the heavy calcium carbonate powder is 400-600 mesh, and the CaCO3 content is 95%-98.5%.

3. The LC according to claim 1 3 The material is characterized by: The particle size of the building gypsum powder is 40~100μm.

4. A method for preparing the LC as described in claim 1 3 The method of materials, characterized in that Includes the following steps: (1) Calcined spherical clay is obtained by calcining the original spherical clay at 650~750℃; (2) Weigh the calcined clay pellets, cement clinker, heavy calcium carbonate powder, and building gypsum powder according to the proportions specified in claim 1, mix them thoroughly, and then grind them until the specific surface area is 300-400 m². 2 / kg.

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