Cement clinker partially replaced by coal gangue and aluminum ore tailings waste residue and preparation method thereof

Abstract

The application relates to the technical field of cement production, and particularly discloses a cement clinker with coal gangue and aluminum tailing waste residue partially replacing fly ash and a preparation method of the cement clinker. The cement clinker with coal gangue and aluminum tailing waste residue partially replacing fly ash comprises the following raw materials in parts by weight: limestone 60-85 parts, fly ash 1-4 parts, aluminum tailing waste residue 2-6 parts, coal gangue 3-5 parts and sandstone 6-9 parts. The application has the advantages that the coal gangue and the aluminum tailing waste residue can be slowly digested in the production process of the cement clinker, and the quality of the cement clinker is not affected.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cement production, in particular to a cement clinker with coal gangue and aluminum ore tailing waste residue partially replacing fly ash and a preparation method thereof. BACKGROUND

[0002] Cement can be rapidly hardened, has high strength, and can resist erosion of fresh water or salt water, is widely used as a building material in civil construction, water conservancy, national defense and other engineering, and the cement clinker is a semi-finished product obtained by mixing limestone, clay and iron raw materials as main raw materials, accordinging to proper proportioning to prepare raw materials, and burning the raw materials to be partially or totally fused and then cooling.

[0003] Fly ash is fine ash collected from flue gas after coal combustion, can replace clay raw materials to produce cement, can improve the strength of cement, and can reduce the cost and improve the performance of water impermeability, air impermeability, sulfate resistance and chemical corrosion resistance; coal gangue is a solid waste discharged in the process of coal mining and coal washing, and aluminum ore tailing is a solid waste after aluminum ore mining, both of which occupy a large amount of land resources after stacking and cause serious pollution to the ecological environment, and the coal gangue contains fixed carbon and is easy to oxidize and self-ignite after long-term stacking, which has a great safety hazard, and how to slowly digest the coal gangue and aluminum ore tailing waste in the production of cement and protect the ecological environment has become a problem to be considered. SUMMARY

[0004] In order to slowly digest the coal gangue and aluminum ore tailing waste in the production process of the cement clinker without affecting the quality of the cement clinker, the application provides a cement clinker with coal gangue and aluminum ore tailing waste partially replacing fly ash and a preparation method thereof.

[0005] The application provides a cement clinker with coal gangue and aluminum ore tailing waste partially replacing fly ash and a preparation method thereof, which adopts the following technical scheme:

[0006] In the first aspect, the application provides a cement clinker with coal gangue and aluminum ore tailing waste partially replacing fly ash, which adopts the following technical scheme:

[0007] The cement clinker with coal gangue and aluminum ore tailing waste partially replacing fly ash comprises the following raw materials in parts by weight: limestone 60-85 parts, fly ash 1-4 parts, aluminum ore tailing waste 2-6 parts, coal gangue 3-5 parts and sandstone 6-9 parts.

[0008] By adopting the technical scheme, a small amount of fly ash can improve the performance of cement in resisting sulfate and resisting chemical corrosion, and can also play the role of aluminum correction material. The aluminum tailings waste residue contains a large amount of aluminum oxide and part of iron oxide, and the use of the aluminum tailings waste residue to partially replace the fly ash can supplement the aluminum oxide and also serve as the iron correction material. In addition, the waste residue contains a large amount of oxides of various types, which can improve the burnability of the clinker. The coal gangue contains a large amount of aluminum oxide, silicon dioxide and iron oxide, and is a clay raw material. The coal gangue can be matched with sandstone to correct the silicon in the cement, and the clinker is more likely to fully react, and the quality of the clinker is more stable. The coal gangue also contains combustible components, which can burn and release heat in the preheating process before sintering, which is beneficial to reducing the coal consumption.

[0009] Preferably, the mass fraction of Al2O3 in the coal gangue is 20-35%, and the mass fraction of Fe2O3 is 10-14%.

[0010] By limiting the mass fraction of aluminum oxide and iron oxide in the coal gangue, it is ensured that the coal gangue can provide sufficient aluminum and iron for the cement. In addition, the aluminum oxide and iron oxide in the coal gangue are easy to be activated at high temperature, which can improve the burnability of the raw material and reduce the calcination temperature, so as to better control the calcination process of the cement clinker.

[0011] Preferably, the mass fraction of Al2O3 in the aluminum tailings waste residue is 45-55%, the mass fraction of Fe2O3 is 8-10%, and the mass fraction of TiO2 is not more than 0.3%.

[0012] By controlling the mass fraction of aluminum oxide and iron oxide, the aluminum tailings waste residue and the coal gangue can cooperate with each other to perform aluminum correction and iron correction. TiO2 is easy to undergo oxidation-reduction reaction in the calcination process to produce alkali vapor to corrode the equipment, but can also form a solid solution with other components. Therefore, by controlling the amount of TiO2, the generation of alkali vapor can be reduced, and the quality of the clinker can be improved.

[0013] Preferably, the coal gangue is pretreated as follows: the coal gangue is screened and ground, the coal gangue is dispersed in tetrachloroethylene to form a mixed solution, and after extraction at 80-100℃, the mixture is centrifuged and washed and dried.

[0014] By adopting the technical scheme, sulfides, sulfur trioxide and other sulfur-containing substances are easy to dissolve in tetrachloroethylene. By using tetrachloroethylene to soak the coal gangue, the sulfur-containing substances in the coal gangue can be reduced, thereby reducing the sulfur-containing flue gas generated during the sintering of the cement and reducing the pollution to the ecological environment.

[0015] Preferably, the specific steps of the coal gangue pretreatment are as follows: the coal gangue is classified into group A coal gangue with a particle size of 13-50 mm and group B coal gangue with a particle size of >50 mm and <13 mm, the group A coal gangue and the group B coal gangue are ground and crushed to obtain group A coal gangue powder and group B coal gangue powder with a particle size of 0.07-0.1 mm, the group A coal gangue powder is dispersed in tetrachloroethylene to form a group A mixture with a coal gangue concentration of 0.1-0.6 g / mL, the group B coal gangue powder is dispersed in tetrachloroethylene to form a group B mixture with a coal gangue concentration of 0.8-1.3 g / mL, extraction is performed at 80-100℃, the extraction time of the group A coal gangue powder is 120-150 min, the extraction time of the group B coal gangue is 60-110 min, and after extraction, centrifugation is performed, the centrifugate is washed, and drying is performed.

[0016] By adopting the technical scheme, the sulfur content in the coal gangue with a particle size of 13-50 mm is high, and the extraction time is prolonged to reduce the sulfur content in the coal gangue, the coal gangue in the particle size range is treated separately to reduce the treatment time and cost, the pretreatment of the coal gangue is easier, the concentration of the coal gangue with other particle sizes is increased, the use amount of tetrachloroethylene is reduced without affecting the extraction effect, and the treatment time and cost are further reduced.

[0017] Preferably, when the tetrachloroethylene mixture of the coal gangue is extracted, the mixture is placed under ultrasonic waves, the ultrasonic wave power is 450-500 W, and the ultrasonic wave frequency is 40-60 kHz.

[0018] By adopting the technical scheme, the impact flow and the like generated by the ultrasonic waves can accelerate the contact between the coal gangue and tetrachloroethylene, the sulfur-containing substances extracted out can quickly diffuse into the solvent, the solid may be broken due to the impact, the contact area between the coal gangue and tetrachloroethylene is increased, and thus the extraction effect of tetrachloroethylene is improved.

[0019] In a second aspect, the application provides a preparation method of cement clinker with coal gangue and aluminum tailings waste residue partially replacing fly ash, which adopts the following technical scheme:

[0020] A preparation method of cement clinker with coal gangue and aluminum tailings waste residue partially replacing fly ash, which comprises the following steps:

[0021] (1) mixing: after dehydration, crushing and grinding of limestone, fly ash, aluminum tailings waste residue, coal gangue and sandstone, the cement raw material is uniformly mixed to obtain cement raw material;

[0022] (2) sintering: after preheating and decomposition, the cement raw material is sintered and cooled to obtain cement clinker.

[0023] Through the above technical scheme, the raw material is dehydrated, crushed and powdered to form particles with uniform and fine granularity, and then sintered at high temperature after being mixed uniformly, and through processes such as carbonate decomposition, silicate formation and solid phase reaction, clinker is formed.

[0024] Preferably, the sintering temperature of the cement raw material is 1310-1360℃, and the sintering time is 60-120min.

[0025] Through the above technical scheme, when the raw material is sintered at a temperature of 1310-1360℃, the cement clinker generated has high hardness and moderate sintering time.

[0026] Preferably, the cement raw material has a rate value of KH 0.900-0.950, SM 2.62-2.85, and IM 1.45-1.52.

[0027] Through the above technical scheme, the KH, SM and IM of the cement raw material are controlled, and both coal gangue and aluminum tailings waste residue can improve the burnability of cement, but too good burnability can cause liquid phase to appear too early, which can cause serious skinning in the kiln. Therefore, the rate value of the raw material is stable, which can make the quality of the generated cement clinker more stable, and can reduce the skinning phenomenon.

[0028] Preferably, the cement clinker has a rate value of KH 0.910-0.960, SM 2.70-2.92, and IM 1.49-1.57.

[0029] Through the above technical scheme, the KH, SM and IM of the cement clinker are controlled, the SM of the clinker is improved, thereby improving the strength and durability of the cement, and the stable IM is conducive to ensuring the stability of the strength of the clinker, thereby stabilizing the quality of the clinker.

[0030] In summary, the present application has the following advantages:

[0031] 1. In the present application, coal gangue and aluminum tailings waste residue are used to partially replace fly ash. Coal gangue contains aluminum oxide, silicon dioxide and iron oxide, aluminum tailings waste residue contains a lot of aluminum oxide and iron oxide, and coal gangue, aluminum tailings waste residue and fly ash cooperate with each other to correct the aluminum in cement. At the same time, coal gangue and aluminum tailings cooperate with each other to correct the iron in cement, which can not only reduce the burnability of clinker, but also stabilize the quality of clinker, and slowly digest coal gangue and aluminum tailings waste residue, reducing the burden on the ecological environment.

[0032] 2. In the present application, tetrachloroethylene is preferably used to soak the coal gangue, which can extract sulfur-containing substances in the coal gangue into tetrachloroethylene, and can perform desulfurization treatment on the coal gangue, reducing the generation of sulfur-containing flue gas during the calcination of raw materials and reducing pollution. DETAILED DESCRIPTION

[0033] The application is further described in detail below with reference to the examples.

[0034] Examples

[0035] Example 1

[0036] A cement clinker partially replacing fly ash with coal gangue and bauxite tailings waste residue comprises the following raw materials by weight: limestone 60 parts, fly ash 1 part, bauxite tailings waste residue 2 parts, coal gangue 3 parts, sandstone 6 parts; wherein the mass fraction of Al2O3 in the coal gangue is 20%, the mass fraction of Fe2O3 is 10%; the mass fraction of Al2O3 in the bauxite tailings waste residue is 45%, the mass fraction of Fe2O3 is 8%, and the mass fraction of TiO2 is 0.1%.

[0037] The preparation method of the above-mentioned cement clinker partially replacing fly ash with coal gangue and bauxite tailings waste residue comprises the following steps: 1. Mixing: after dehydration, crushing, and powdering the limestone, fly ash, bauxite tailings waste residue, coal gangue, and sandstone respectively, the cement raw material is uniformly mixed to obtain a cement raw material; wherein the rate value of the cement raw material is: KH is 0.900, SM is 2.62, and IM is 1.45; 2. Sintering: after preheating and decomposition, the cement raw material is sintered at 1310℃ for 120min, and then cooled to obtain a cement clinker; wherein the rate value of the cement clinker is: KH is 0.910, SM is 2.70, and IM is 1.49.

[0038] Example 2

[0039] A cement clinker partially replacing fly ash with coal gangue and bauxite tailings waste residue comprises the following raw materials by weight: limestone 85 parts, fly ash 4 parts, bauxite tailings waste residue 6 parts, coal gangue 5 parts, and sandstone 9 parts; wherein the mass fraction of Al2O3 in the coal gangue is 35%, the mass fraction of Fe2O3 is 14%; the mass fraction of Al2O3 in the bauxite tailings waste residue is 55%, the mass fraction of Fe2O3 is 10%, and the mass fraction of TiO2 is 0.3%.

[0040] The preparation method of the above-mentioned cement clinker partially replacing fly ash with coal gangue and bauxite tailings waste residue comprises the following steps: 1. Mixing: after dehydration, crushing, and powdering the limestone, fly ash, bauxite tailings waste residue, coal gangue, and sandstone respectively, the cement raw material is uniformly mixed to obtain a cement raw material; wherein the rate value of the cement raw material is: KH is 0.950, SM is 2.85, and IM is 1.52; 2. Sintering: after preheating and decomposition, the cement raw material is sintered at 1360℃ for 60min, and then cooled to obtain a cement clinker; wherein the rate value of the cement clinker is: KH is 0.960, SM is 2.92, and IM is 1.57.

[0041] Example 3

[0042] Example 3 differs from Example 1 in that the coal gangue is pretreated as follows: the coal gangue is sieved into A group coal gangue with a particle size of 13-50 mm, B group coal gangue with a particle size of >50 mm and a particle size of <13 mm, the A group coal gangue and the B group coal gangue are both ground and pulverized to obtain A group coal gangue powder and B group coal gangue powder with a particle size of 0.07 mm, the A group coal gangue powder is dispersed in tetrachloroethylene to form an A group mixture with a coal gangue concentration of 0.1 g / mL, the B group coal gangue powder is dispersed in tetrachloroethylene to form a B group mixture with a coal gangue concentration of 0.8 g / mL, both are extracted at 80°C, the extraction time of the A group coal gangue powder is 120 min, the extraction time of the B group coal gangue is 60 min, after extraction, centrifugation is performed, the centrifugate is washed and dried.

[0043] Example 4

[0044] Example 4 differs from Example 1 in that the coal gangue is pretreated as follows: the coal gangue is sieved into A group coal gangue with a particle size of 13-50 mm, B group coal gangue with a particle size of >50 mm and a particle size of <13 mm, the A group coal gangue and the B group coal gangue are both ground and pulverized to obtain A group coal gangue powder and B group coal gangue powder with a particle size of 0.1 mm, the A group coal gangue powder is dispersed in tetrachloroethylene to form an A group mixture with a coal gangue concentration of 0.6 g / mL, the B group coal gangue powder is dispersed in tetrachloroethylene to form a B group mixture with a coal gangue concentration of 1.3 g / mL, both are extracted at 100°C, the extraction time of the A group coal gangue powder is 150 min, the extraction time of the B group coal gangue is 110 min, after extraction, centrifugation is performed, the centrifugate is washed and dried.

[0045] Example 5

[0046] Example 5 differs from Example 1 in that the coal gangue is not sieved, the coal gangue is ground and pulverized to obtain coal gangue powder with a particle size of 0.07-0.1 mm, the coal gangue powder is dispersed in tetrachloroethylene to form a mixture with a coal gangue concentration of 0.2 g / mL, extraction is performed at 80°C, the extraction time is 120 min, after extraction, centrifugation is performed, the centrifugate is washed and dried.

[0047] Example 6

[0048] Example 6 differs from Example 3 in that the concentration of coal gangue in the A group mixture is 0.01 g / mL.

[0049] Example 7

[0050] Example 7 differs from Example 3 in that the concentration of coal gangue in the A group mixture is 1.2 g / mL.

[0051] Example 8

[0052] Example 8 differs from Example 3 in that the concentration of coal gangue in the B group mixed solution is 0.4 g / mL.

[0053] Example 9

[0054] Example 9 differs from Example 3 in that the concentration of coal gangue in the B group mixed solution is 2 g / mL.

[0055] Example 10

[0056] Example 10 differs from Example 3 in that the extraction time of the A group coal gangue powder is 60 min and the extraction time of the B group coal gangue powder is 30 min.

[0057] Example 11

[0058] Example 11 differs from Example 3 in that the extraction time of the A group coal gangue powder is 200 min and the extraction time of the B group coal gangue is 150 min.

[0059] Example 12

[0060] Example 12 differs from Example 3 in that the tetrachloroethylene mixed solution of coal gangue is placed under ultrasonic waves during extraction, the ultrasonic wave power is 450 W, and the ultrasonic wave frequency is 40 kHz.

[0061] Example 13

[0062] Example 13 differs from Example 3 in that the tetrachloroethylene mixed solution of coal gangue is placed under ultrasonic waves during extraction, the ultrasonic wave power is 500 W, and the ultrasonic wave frequency is 60 kHz.

[0063] Comparative Example

[0064] Comparative Example 1

[0065] Comparative Example 1 differs from Example 1 in that an equal amount of fly ash is used to replace the aluminum stone tailings waste residue, i.e., includes the following raw materials in parts by weight: limestone 70 parts, fly ash 3 parts, coal gangue 3 parts, sandstone 6 parts, and does not contain aluminum stone tailings waste residue.

[0066] Comparative Example 2

[0067] Comparative Example 2 differs from Example 1 in that an equal amount of fly ash is used to replace coal gangue, i.e., includes the following raw materials in parts by weight: limestone 70 parts, fly ash 4 parts, aluminum stone tailings waste residue 2 parts, sandstone 6 parts, and does not contain coal gangue.

[0068] Comparative Example 3

[0069] Comparative Example 3 differs from Example 1 in that an equal amount of fly ash is used instead of coal gangue and aluminum stone tailings waste, i.e., the following raw materials are included in parts by weight: limestone 70 parts, fly ash 6 parts, sandstone 6 parts, without coal gangue and aluminum stone tailings waste.

[0070] Detection method / test method

[0071] 1. The cement clinkers of Examples 1-13 and Comparative Examples 1-2 were subjected to mortar molding, and the physical properties of the clinker were detected, with the test method referring to GB-T 17671-2021 “Cement Mortar Strength Test Method (ISO Method)”. The test results are recorded in Table 1.

[0072] Table 1 Strength of Cement Clinker

[0073]

[0074]

[0075] The aluminum stone tailings waste and coal gangue used in Examples 1-2 replaced part of the fly ash, and no coal gangue and aluminum stone tailings waste were used in Comparative Example 3. After mortar molding of Examples 1-2 and Comparative Example 3, the compressive strength (3d) and flexural strength (3d) of the clinker were similar, indicating that after partial replacement of fly ash with aluminum stone tailings waste and coal gangue, by controlling the addition ratio of aluminum stone tailings waste and coal gangue, the physical properties of the cement clinker prepared after partial replacement of fly ash with aluminum stone tailings waste and coal gangue were similar to those of the cement clinker prepared before partial replacement of fly ash with aluminum stone tailings waste and coal gangue, indicating that the preparation of cement clinker by using aluminum stone tailings waste and coal gangue to partially replace fly ash can also maintain the quality of the cement clinker, and can consume aluminum stone tailings waste and coal gangue during preparation, gradually eliminating solid waste, which is conducive to protecting the ecological environment. After mortar molding of Examples 1-2, the compressive strength and flexural strength of the clinker at 28d were higher than those of Comparative Example 3, indicating that the addition of aluminum stone tailings waste and coal gangue can improve the strength of the cement, and it is speculated that this is because the aluminum stone tailings waste and coal gangue contain a large number of oxides, which can effectively improve the burnability of the clinker, thereby improving the strength of the cement.

[0076] The cement clinker of Comparative Example 1 has slightly decreased strength at 28d compared to Example 1, which is presumably because the aluminum stone tailings slag contains a large number of oxides, and the burnability of Comparative Example 1 is slightly lower than that of Example 1, so the strength of the cement clinker of Comparative Example 1 is slightly reduced at 28d. In Comparative Example 2, coal gangue is not added, and the strength of the cement clinker is comparable to that of Example 1. The raw meal of Example 1 is preheated and decomposed, and the outlet temperature of the first-stage cylinder is 10°C higher than that of Comparative Example 2, which indicates that the coal gangue can be combusted and released heat during preheating, thereby reducing coal consumption and having a certain positive effect on energy saving.

[0077] Example 3-4 is a desulfurization treatment of coal gangue in the raw material, and the strength of Example 3-4 is higher than that of Example 1, which indicates that after the desulfurization treatment of coal gangue, the sulfur content in the raw material is reduced, and the organic sulfur and inorganic sulfur in the raw material are easy to interact with CaO to generate CaSO4, thereby reducing the KH of the cement clinker and reducing the strength of the cement clinker. After desulfurization, the KH of the cement is increased, which can further improve the strength of the cement, and due to the mineralization of SO3 during the sintering process, it is easy to increase the liquid phase, and the skin and dead burning material block are prone to occur, which reduces the quality of the cement clinker. Desulfurization treatment of coal gangue can alleviate this situation, thereby improving the quality of the cement clinker.

[0078] 2. The sulfur content of the coal gangue in the raw material of Examples 1-13 is detected using SC-132 total sulfur tester, and the detection results are recorded in Table 2.

[0079] Table 2 Sulfur content of coal gangue in raw material

[0080] Item Sulfur content / % Example 1 4.21 Example 2 4.16 Example 3 2.41 Example 4 2.38 Example 5 3.21 Example 6 1.13 Example 7 2.92 Example 8 1.21 Example 9 2.74 Example 10 3.16 Example 11 1.81 Example 12 1.24 Example 13 1.16

[0081] Example 1-2 is not pretreated with coal gangue, while Example 3-4 is desulfurized with coal gangue in the raw material. After screening, the particle size of the coal gangue in group A is 13-50mm, and the coal gangue in this particle size range contains a large amount of pyrite. The concentration of coal gangue in the mixed solution of group A is lower than that of group B, that is, the mass ratio of coal gangue to tetrachloroethylene in the mixed solution of group A is lower than that of group B, and the extraction time of coal gangue in group A is longer. Sufficient tetrachloroethylene is used to extract and treat group A coal gangue to reduce the sulfur content of group A coal gangue. The sulfur content of group B coal gangue is relatively low, and less tetrachloroethylene can be used for treatment. The treated group A coal gangue and group B coal gangue are mixed, the overall sulfur content of the coal gangue is reduced, the emission of sulfur-containing substances generated by the combustion of coal gangue during the preheating and decomposition of the raw meal is reduced, and the sulfur content in the cement clinker is also reduced, thereby improving the strength of the cement clinker.

[0082] Compared with Example 3, Example 5 does not screen the coal gangue, but directly uses more tetrachloroethylene to treat the coal gangue. However, the sulfur content of Example 5 is higher than that of Example 3, and the amount of tetrachloroethylene used in Example 5 is more than that of Example 3. It is indicated that after screening the coal gangue, separately treating the A group of coal gangue with high sulfur content can reduce the use amount of tetrachloroethylene, the treatment cost is lower, and the desulfurization effect of the coal gangue is better.

[0083] Compared with Example 3, Examples 6-7 adjust the concentration of the coal gangue in the A group of mixed solution. The concentration of the coal gangue in the A group of mixed solution is reduced in Example 6, and the concentration of the coal gangue in the A group of mixed solution is increased in Example 7. Compared with Example 3, the sulfur content of Example 6 is further reduced, but the amount of tetrachloroethylene is greatly increased. In Example 3, the sulfur content of the coal gangue meets the production requirements. Compared with Example 3, the sulfur content of Example 7 is increased, which indicates that the concentration of the coal gangue in Example 7 is too high, and the total amount of sulfur-containing substances is also high, so that the desulfurization treatment effect of tetrachloroethylene on the coal gangue is poor.

[0084] Compared with Example 3, Examples 8-9 adjust the concentration of the coal gangue in the B group of mixed solution. The concentration of the coal gangue in the B group of mixed solution is reduced in Example 8, and the concentration of the coal gangue in the B group of mixed solution is increased in Example 9. Compared with Example 3, the sulfur content of the coal gangue in Example 8 is reduced. As in Example 6, the amount of tetrachloroethylene is greatly increased, which is unnecessary waste. Compared with Example 3, the sulfur content of the coal gangue in Example 9 is increased, but the increase range of the sulfur content is lower than that of Example 7, which can indicate that the sulfur content of the B group of coal gangue is lower than that of the A group of coal gangue, and the desulfurization effect of the B group of coal gangue is poor, and the influence on the sulfur content of the coal gangue is smaller.

[0085] Compared with Example 3, Examples 10-11 adjust the extraction time of the A group of mixed solution and the B group of mixed solution. The extraction time of the A group of mixed solution and the B group of mixed solution is reduced in Example 10, and the extraction time of the A group of mixed solution and the B group of mixed solution is increased in Example 11. Compared with Example 3, the sulfur content of Example 10 is increased, and the sulfur content of Example 11 is reduced. It is indicated that the desulfurization effect of tetrachloroethylene on the coal gangue is directly affected by the extraction time. The longer the extraction time is, the better the desulfurization effect of the coal gangue is.

[0086] Compared with Example 3, the sulfur content of Examples 12-13 is reduced, which shows that increasing the ultrasonic treatment can improve the extraction effect of tetrachloroethylene on the sulfur-containing substances in the coal gangue. The impact flow generated by the ultrasonic treatment can accelerate the contact between the coal gangue and tetrachloroethylene, accelerate the diffusion of the sulfur-containing substances into tetrachloroethylene, and at the same time, the coal gangue may be broken by the impact, increasing the contact area between the coal gangue and tetrachloroethylene, thereby improving the extraction effect of tetrachloroethylene.

[0087] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A cement clinker in which coal gangue, aluminum stone tailings waste residue partially replaces fly ash, characterized by: The raw materials include the following components by weight: limestone 60-85 parts, fly ash 1-4 parts, aluminum ore tailings waste residue 2-6 parts, coal gangue 3-5 parts, and sandstone 6-9 parts; The coal gangue is pretreated as follows: the coal gangue is screened and ground, the coal gangue is dispersed in tetrachloroethylene to form a mixed solution, and after extraction at 80-100℃, centrifugation, and washing and drying of the centrifugate, the coal gangue is obtained. The specific steps of the coal gangue pretreatment are as follows: the coal gangue is screened into A group coal gangue with a particle size of 13-50mm, B group coal gangue with a particle size of >50mm and <13mm, the A group coal gangue and the B group coal gangue are ground, A group coal gangue powder and B group coal gangue powder with a particle size of 0.07-0.1mm are obtained, the A group coal gangue powder is dispersed in tetrachloroethylene to form an A group mixed solution with a coal gangue concentration of 0.1-0.6g / mL, the B group coal gangue powder is dispersed in tetrachloroethylene to form a B group mixed solution with a coal gangue concentration of 0.8-1.3g / mL, and extraction is carried out at 80-100℃, the extraction time of the A group coal gangue powder is 120-150min, the extraction time of the B group coal gangue is 60-110min, and after extraction, centrifugation, washing, and drying of the centrifugate, the coal gangue is obtained.

2. The cement clinker according to claim 1, wherein the coal gangue, aluminum ore tailings waste partially replaces fly ash. The mass fraction of Al2O3 in the coal gangue is 20-35%, and the mass fraction of Fe2O3 is 10-14%.

3. The cement clinker according to claim 1, which partially replaces fly ash with coal gangue and bauxite tailings waste, is characterized in that: The mass fraction of Al2O3 in the aluminum ore tailings waste residue is 45-55%, the mass fraction of Fe2O3 is 8-10%, and the mass fraction of TiO2 is not more than 0.3%.

4. The cement clinker according to claim 1, wherein the coal gangue, aluminum ore tailings waste partially replaces fly ash. When the tetrachloroethylene mixed solution of the coal gangue is extracted, the mixed solution is placed under ultrasonic waves, the ultrasonic wave power is 450-500W, and the ultrasonic wave frequency is 40-60kHz.

5. The method according to any one of claims 1-4, characterized in that: The method comprises the following steps: (1) mixing: the limestone, fly ash, aluminum ore tailings waste residue, coal gangue, and sandstone are respectively dehydrated, crushed, and ground, and then uniformly mixed to obtain cement raw material; (2) sintering: the cement raw material is preheated and decomposed, and then sintered and cooled to obtain cement clinker.

6. The method according to claim 5, wherein the cement clinker is prepared by using coal gangue, aluminum stone tailings waste residue and fly ash. The sintering temperature of the cement raw material is 1310-1360℃, and the sintering time is 60-120min.

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