Cement composition and preparation method thereof
By mixing the mine peeling material with cement in a certain proportion, drying, drying and refining the treatment, the problems of complex processes and high energy consumption in the existing technology are solved, and the preparation of mixed cement with simplified processes and superior performance is achieved. Reduced cement production costs and CO2 emissions.
Patent Information
- Application Number
- CN202411185501.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2024-12-27
AI Technical Summary
In the prior art, the process of using solid waste to prepare mixed cement is complex, and other minerals or agents are required to adjust the performance, and the calcination step is required to increase energy consumption.
By mixing the mine release material with cement in a certain proportion, drying, drying and refining, a cement composition is prepared. The process is simplified, the energy consumption is low, and the additives are required. The mine release material is used to replace part of the cement.
It realizes mixed cement preparation with simple process, low energy consumption and superior performance, reduces cement production costs and effectively reduces CO2 emissions.
Smart Images
Figure CN119191779A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of solid waste construction material conversion, and in particular to a cement composition and a preparation method thereof. Background Art
[0002] Mine stripping materials are soil waste materials covering the surface of sand and stone when mining machine-made sand. At present, the main way for the machine-made sand industry to deal with this waste is open-air storage. Nowadays, the machine-made sand industry is huge, and the increasing demand for machine-made sand has led to increasingly serious storage of mine stripping materials. The long-term storage of mine stripping materials will not only cause a waste of land resources and management funds, but also cause environmental and safety problems such as dust, vegetation destruction, mudslides, and landslides. Therefore, in order to alleviate the series of problems caused by the storage of mine stripping materials, the resource utilization of mine stripping materials has become an important issue that the machine-made sand production industry urgently needs to solve.
[0003] On the other hand, with the acceleration of urbanization in human society, the demand for cement is increasing. In China, the consumption of cement has reached about 2 billion tons per year, which has led to increasingly serious CO2 emissions caused by cement production. Therefore, in order to alleviate the carbon pollution caused by cement production and reduce the CO2 emissions from cement production, it has become an important task that the cement production industry urgently needs to promote. Among the many methods of carbon emission reduction, the method of replacing part of the cement with a mixture with potential volcanic ash activity to achieve cement production reduction and thus reduce CO2 emissions is the simplest and most effective. Mine stripping material is slightly alkaline and mainly consists of a large amount of siliceous minerals and a small amount of aluminum and iron minerals. This acid-base property and composition characteristics make it have potential volcanic ash activity. In addition, the alkaline environment formed by the cement hydration process also has an stimulating effect on volcanic ash activity. Therefore, mine stripping material is extremely suitable as a mixture for the production of mixed cement.
[0004] At present, there are few patents related to the preparation of mixed cement from mine stripping materials, and the theoretical and practical development is still imperfect. In the prior art, Chinese patent CN110128043A discloses a submicron active admixture and its preparation method, which uses stone powder produced in the process of machine-made sand production as raw material, and prepares cement admixture through batching, grinding, mixing and other processes. However, this patent requires the addition of admixtures of different components in the batching step to improve the performance of the admixture. In addition, during the grinding process of the process, grinding aids and alkali activators are also required to improve the fineness and activity of the admixture. Chinese patent CN 112960919 A discloses a method for preparing cement admixture using sand washing sludge, which uses sand washing sludge in the process of machine-made sand production as raw material, and prepares cement admixture through drying, calcination, ball milling and other processes, and finally obtains a cement product with a 28-day compressive strength of 33.7 MPa. The preparation of this patent requires a calcination step, which increases production costs.
[0005] In summary, the current methods of using solid waste to prepare mixed cement have the following problems: ① The preparation process is cumbersome and the process is complicated; ② Other minerals or agents need to be added to adjust the performance; ③ It needs to be calcined before it can be used, and the energy consumption is high. Summary of the invention
[0006] In view of the above-mentioned deficiencies, the object of the present invention is to provide a cement composition and a preparation method thereof, so as to solve the problems of the prior art of preparing mixed cement using solid waste, such as complex process, large amount of additives used, and high energy consumption.
[0007] To achieve the above object, the present invention is implemented through the following technical solutions: In one aspect, the present invention provides a cement composition, which comprises, by weight percentage, 85-95% cement and 5-15% mine stripping material.
[0008] Preferably, the mine stripping material includes 40-60% SiO2, 20-30% Al2O3, and 5-15% Fe2O3.
[0009] Preferably, the fineness of the mine stripping material is ≤-200 mesh.
[0010] Preferably, the cement is Portland cement.
[0011] Preferably, the silicate cement is one or more of 52.5 grade silicate cement, 42.5 grade silicate cement, and 32.5 grade silicate cement.
[0012] In a second aspect, the present invention provides a method for preparing a cement composition, comprising the following steps: S1, drying and mixing the mine stripping material to obtain a homogenized material; S2, drying the homogenized material to obtain a dry material; S3, refining the dried material to obtain refined material; S4, mixing the refined material with cement to obtain a cement composition.
[0013] Preferably, in step S1, the drying is natural airing, and the number of days for airing can be 3-5 days. Preferably, in step S1, the mixing method is the reduction method. Sample reduction means that the sample is divided into several parts according to the weight, mixed, and then divided into the same number of parts. After several cycles, the reduced parts are taken as the material for subsequent operations. The purpose of this operation is to make the sample composition uniform and the sample performance stable.
[0014] Preferably, the drying temperature is 60 to 80°C and the drying time is 24 to 48 hours.
[0015] Preferably, the refinement step comprises: grinding the dry material and then sieving to obtain a refined material.
[0016] The beneficial effects of the present invention are: The present invention utilizes mine stripping material as raw material to replace 5-15wt% of standard cement to prepare blended cement. The process is simple and easy, with low energy consumption and short preparation cycle, and no other additives need to be added. While realizing resource utilization of mine stripping material, a blended cement product with superior performance is obtained, which reduces the cost of using only standard cement and also contributes to carbon emission reduction in the cement production industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.
[0018] Figure 1 The present invention is a process flow chart of the preparation of a cement composition. DETAILED DESCRIPTION
[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0020] The mine stripping material of the present invention is the soil waste covering the surface of sand and stone when mining machine-made sand, and its main mineral components are mainly quartz, amphibole, feldspar and mica, etc. The composition of the mine stripping material used in the following examples and comparative examples is shown in Table 1.
[0021] Table 1 Chemical composition of mine stripping materials
[0022] Example 1 A cement composition, the preparation method of which is as follows Figure 1 As shown, the following steps are included: S1. Drying and mixing: After the mine stripping material is dried for 3-5 days, the raw material is divided into four parts according to the weight and mixed, and then divided into four parts again. According to this step, the raw material is divided 6-8 times to make the composition uniform and obtain a homogenized material.
[0023] S2. Drying: Dry the homogenized material obtained in S1 at 80°C in a forced air drying oven for 24 h to remove attached water and obtain a dry material.
[0024] S3, grinding and refining: use a ball mill to grind the dry material obtained in S2, and after passing through a 200-mesh sieve, the refined material is under the sieve.
[0025] S4. Mixing ingredients: 5 wt% of the refined material and 95 wt% of 52.5 grade Portland cement are uniformly mixed to obtain a cement composition.
[0026] Example 2 A cement composition, the preparation method is as follows: S1. Drying and mixing: After the mine stripping material is dried for 3-5 days, the raw material is divided into four parts according to the weight and mixed, and then divided into four parts again. According to this step, the raw material is divided 6-8 times to make the composition uniform and obtain a homogenized material.
[0027] S2. Drying: Dry the homogenized material obtained in S1 at 80°C in a forced air drying oven for 24 h to remove attached water and obtain a dry material.
[0028] S3, grinding and refining: use a ball mill to grind the dry material obtained in S2, and after passing through a 200-mesh sieve, the refined material is under the sieve.
[0029] S4. Mixing ingredients: 10 wt% of the refined material and 90 wt% of 52.5 grade Portland cement are uniformly mixed to obtain a cement composition.
[0030] Example 3 A cement composition, the preparation method is as follows: S1. Drying and mixing: After the mine stripping material is dried for 3-5 days, the raw material is divided into four parts according to the weight and mixed, and then divided into four parts again. According to this step, the raw material is divided 6-8 times to make the composition uniform and obtain a homogenized material.
[0031] S2. Drying: Dry the homogenized material obtained in S1 at 80°C in a forced air drying oven for 24 h to remove attached water and obtain a dry material.
[0032] S3, grinding and refining: use a ball mill to grind the dry material obtained in S2, and after passing through a 200-mesh sieve, the refined material is under the sieve.
[0033] S4. Mixing ingredients: 15 wt% of the refined material and 85 wt% of 52.5 grade Portland cement are uniformly mixed to obtain a cement composition.
[0034] Comparative Example 1 A cement composition, the preparation method is as follows: S1. Drying and mixing: After the mine stripping material is dried for 3-5 days, the raw material is divided into four parts according to the weight and mixed, and then divided into four parts again. According to this step, the raw material is divided 6-8 times to make the composition uniform and obtain a homogenized material.
[0035] S2. Drying: Dry the homogenized material obtained in S1 at 80°C in a forced air drying oven for 24 h to remove attached water and obtain a dry material.
[0036] S3, grinding and refining: use a ball mill to grind the dry material obtained in S2, and after passing through a 200-mesh sieve, the refined material is under the sieve.
[0037] S4. Mixing ingredients: 20 wt% of the refined material and 80 wt% of 52.5 grade Portland cement are uniformly mixed to obtain a cement composition.
[0038] Comparative Example 2 A cement composition, the preparation method is as follows: S1. Drying and mixing: After the mine stripping material is dried for 3-5 days, the raw material is divided into four parts according to the weight and mixed, and then divided into four parts again. According to this step, the raw material is divided 6-8 times to make the composition uniform and obtain a homogenized material.
[0039] S2. Drying: Dry the homogenized material obtained in S1 at 80°C in a forced air drying oven for 24 h to remove attached water and obtain a dry material.
[0040] S3, grinding and refining: use a ball mill to grind the dry material obtained in S2, and after passing through a 200-mesh sieve, the refined material is under the sieve.
[0041] S4. Mixing ingredients: 25 wt% of the refined material and 75 wt% of 52.5 grade Portland cement are uniformly mixed to obtain a cement composition.
[0042] The compressive strength and setting time of the cement compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were tested respectively, and the results are shown in Tables 2 and 3.
[0043] Table 2 Compressive strength test results of Examples 1 to 3 and Comparative Examples 1 to 2
[0044] Table 3 Coagulation time test results of Examples 1 to 3 and Comparative Examples 1 to 2
[0045] It can be seen from Table 2 and Table 3 that the 28-day compressive strength of the mixed cement test blocks prepared in Examples 1 to 3 of the present invention is higher than that of the 42.5-grade silicate cement test blocks, and the setting time thereof is also within the qualified range specified by the national standard. This indicates that the present invention can prepare 42.5-grade silicate cement by mixing mine stripping material with 52.5-grade silicate cement, because the alkaline environment formed by silicate cement stimulates the potential volcanic ash activity in the mine stripping material, forming a strong mineral phase such as hydrated calcium silicate, thereby partially compensating for the decrease in strength.
[0046] Compared with the example, Comparative Example 1 uses a higher dosage of mine stripping material, which leads to a sharp decrease in the later compressive strength. This shows that the use of a high dosage cannot completely make up for the reduction of cementitious materials, which ultimately leads to a decrease in strength. Compared with the example, Comparative Example 2 further uses a higher dosage, and the compressive strength of the cement test block decreases sharply, and its setting time does not meet the national standard.
[0047] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.
[0048] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A cement composition, characterized in that Calculated by weight, it includes 85-95% cement and 5-15% mine stripping material.
2. The cement composition according to claim 1, characterized in that The mine stripping material includes 40-60% SiO2, 20-30% Al2O3, and 5-15% Fe2O3.
3. The cement composition according to claim 1, characterized in that The fineness of the mine stripping material is ≤-200 mesh.
4. The cement composition according to claim 1, characterized in that The cement is silicate cement.
5. The cement composition according to claim 4, characterized in that The silicate cement is one or more of 52.5 grade silicate cement, 42.5 grade silicate cement and 32.5 grade silicate cement.
6. A method for preparing a cement composition according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, drying and mixing the mine stripping material to obtain a homogenized material; S2, drying the homogenized material to obtain a dry material; S3, refining the dried material to obtain a refined material; S4, mixing the refined material with cement to obtain the cement composition.
7. The method for preparing the cement composition according to claim 6, characterized in that: In step S1, the drying is natural drying.
8. The method for preparing the cement composition according to claim 6, characterized in that: In step S1, the mixing method is the reduction method.
9. The method for preparing the cement composition according to claim 6, characterized in that: In step S2, the drying temperature is 60 to 80° C. and the drying time is 24 to 48 hours.
10. The method for preparing the cement composition according to claim 6, characterized in that: In step S3, the refinement step includes: grinding the dry material and then sieving to obtain the refined material.