An activated coal gangue early strength mixture and fluidity adjusting material and preparation method thereof

Abstract

The invention discloses an activated coal gangue early strength mixed material and a fluidity adjusting material and a preparation method thereof. After selecting the coal gangue, the mixed material is first crushed, and then the coal gangue is calcined and activated at high temperature to form a calcined activated material; the calcined activated material is finely crushed and activated to form a mixed material with a specific surface area of ​​600 to 1000 m 2 / kg activated coal gangue material; the coal gangue is clay coal gangue with a mass ratio of Al2O3 to SiO2 greater than or equal to 0.28; the high calcium raw material is dried, surface impurities are removed and then crushed to form an active high calcium material; the active high calcium material is added according to 5-50% of the mass of the activated coal gangue material and then mixed and ground for homogenization; the mixed material is put into an aging bin and aged to form an activated coal gangue early strength mixture and a fluidity adjustment material. The activity reaches 95% in 3 days and 96% in 28 days, and the fluidity is greatly improved. The amount of cement admixture used to replace clinker reaches 30-50%.

Description

Technical Field

[0001] The invention belongs to the field of modification and treatment of coal gangue, and relates to an activated coal gangue early strength mixture and fluidity adjusting material and a preparation method thereof. Background Art

[0002] Gangue is solid waste removed during coal mining and washing. my country is a major coal-producing country with a huge amount of gangue emissions, accounting for about 10-20% of coal production. By 2022, my country's cumulative stockpile of gangue will exceed 7 billion tons, and will increase by 100 million tons each year. Large-scale disposal and high-value comprehensive utilization of gangue are severe challenges facing my country. Calcining gangue as a cement admixture is an effective way to utilize gangue. Since calcined gangue, i.e. cement admixture, is not very active (generally active H 28 =70-80%), and at the same time, the early strength is low (active H3 = 60-70%), the fluidity is poor, and when used to produce cement with the label (PC42.5), the addition amount is small (less than or equal to 10%), which seriously restricts the resource utilization of coal gangue in the cement industry. Summary of the invention

[0003] The purpose of the embodiments of the present invention is to provide an activated coal gangue early strength mixture and fluidity adjusting material and a preparation method thereof, so as to solve the problems of low activity, low early strength, poor fluidity and small addition amount of calcined coal gangue when calcined coal gangue is used as a mixed material for cement.

[0004] The technical solution adopted in the embodiment of the present invention is: an activated coal gangue early strength mixture and fluidity adjusting material, comprising activated coal gangue material and active high calcium material.

[0005] Furthermore, the active high calcium material is active limestone material, and the active limestone material accounts for 5-50% of the mass of the activated coal gangue material.

[0006] Furthermore, the specific surface area of ​​the activated coal gangue material is 600 to 1000 m 2 / kg, the specific surface area of ​​the active high calcium material is 500-600m 2 / kg.

[0007] Furthermore, it can be used as a cement admixture to prepare PC42.5 and PC52.5 cement.

[0008] Another technical solution adopted in the embodiment of the present invention is: a method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material, comprising the following steps:

[0009] After selecting the coal gangue, it is first crushed, and then calcined and activated at high temperature to form calcined activated material;

[0010] Finely crushing and activating the calcined activated material to form activated coal gangue material;

[0011] The high calcium raw material is dried, surface impurities are removed and then crushed to form active high calcium material;

[0012] Add active high calcium material according to 5-50% of the mass of activated coal gangue material and mix and grind to homogenize;

[0013] The mixed and ground materials are put into the aging bin for aging to form active coal gangue early strength mixture and fluidity adjustment material.

[0014] Furthermore, the coal gangue is crushed and calcined at 600-900° C. for 3-6 hours to form a calcined activated material.

[0015] Furthermore, the coal gangue is selected to be clay coal gangue with a mass ratio of Al2O3 to SiO2 greater than or equal to 0.28, and the mass percentage of CaO in the high calcium raw material is greater than or equal to 45%.

[0016] Furthermore, the chemical composition of the clayey coal gangue used includes: SiO2 30-60%, Al2O3 12-33%, Fe2O31.9-10%, CaO 1-6%, MgO 0.1-3%, SO3 0.1-4%, K2O 0.7-2%, Na2O 0.5-2%, the loss on ignition is 8-22%, and the remaining components are trace elements, and the total mass percentage is 100%.

[0017] Furthermore, the chemical composition of the high calcium raw material used includes: SiO2 0.2-10%, Al2O3 0.2-2.5%, Fe2O3 0.1-2%, CaO 45-55%, MgO 0.1-2.5%, the loss on ignition is 36-43%, and the remaining components are trace elements, and the total mass percentage is 100%.

[0018] Furthermore, after mixing, the mixture is homogenized in a ball mill for 10 to 20 minutes, and the mixed material is aged in an aging bin for 12 to 24 hours to form an activated coal gangue early strength mixture and a fluidity adjustment material.

[0019] The beneficial effects of the embodiments of the present invention are: the three-day activity of coal gangue reaches 95%, which is about 50% higher than the three-day activity H3 of the currently activated coal gangue; the later active H 28Reach 96%, a significant improvement; 5-10% higher than the activity of pure activated coal gangue, greatly improved fluidity; a large amount of replacement of clinker as cement admixture, the admixture reaches 30-50%, better than the performance of cement mixed with fly ash and other industrial waste slag, strength and construction performance close to pure cement performance. Realize the resource utilization of coal gangue and harmless treatment. And it can replace the current cement additives mineral powder and fly ash in large quantities, save resources, save energy and reduce carbon, and greatly reduce costs. It solves the current problems of low activity, low early strength, poor fluidity and small admixture of calcined coal gangue when it is used as a mixed material for cement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a flow chart of a method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material of this embodiment. DETAILED DESCRIPTION

[0022] 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.

[0023] Example 1

[0024] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material, such as Figure 1 As shown, the following steps are included:

[0025] After the gangue is selected and crushed, it is calcined at 600-900℃ for 3-6 hours for high-temperature calcination activation. After the gangue is calcined, the carbon and organic matter in it are burned to generate carbon dioxide and emit, which reduces the loss on ignition. On the other hand, the clay minerals in the gangue are dehydrated and decomposed to form amorphous metakaolin and silicon dioxide (SiO2) and aluminum oxide (Al2O3) with high activity, forming a calcination activation material.

[0026] The calcined activated material is finely crushed and activated, and ground to a specific surface area of ​​600-1000m 2 / kg, forming activated coal gangue material;

[0027] The high calcium raw material is dried, the surface mud and other impurities are removed, and then crushed to a specific surface area of ​​500-600m 2 / kg, forming active high calcium material, the mass percentage of CaO in the high calcium raw material is greater than or equal to 45%;

[0028] Add active high calcium material to 5-50% of the activated coal gangue mass and mix and grind for 10-20 minutes;

[0029] The mixed and ground materials are put into an aging bin and aged for 12 to 24 hours to form an activated coal gangue early strength mixture and a fluidity adjustment material.

[0030] The coal gangue should be clay coal gangue with a mass ratio of Al2O3 to SiO2 greater than or equal to 0.28, and quartz stone, siderite, wood chips, plastic and waste steel bars should be removed.

[0031] The chemical composition of the clayey coal gangue used includes: SiO2 30-60%, Al2O3 12-33%, Fe2O3 1.9-10%, CaO 1-6%, MgO 0.1-3%, SO3 0.1-4%, K2O 0.7-2%, Na2O 0.5-2%, the loss on ignition is 8-22%, and the remaining components are trace elements, and the total mass percentage is 100%.

[0032] The chemical composition of the high calcium raw material used includes: SiO2 0.2-10%, Al2O3 0.2-2.5%, Fe2O3 0.1-2%, CaO45-55%, MgO 0.1-2.5%, the ignition loss is 36-43%, and the remaining components are trace elements, and the total mass percentage is 100%.

[0033] After the gangue is selected, it is first coarsely crushed to a particle size of less than or equal to 20 mm, then medium crushed to a particle size of 3-5 mm, and finally finely crushed to a particle size of less than or equal to 1 mm.

[0034] Coarse and medium crushing can be done by jaw crusher, impact crusher, vertical impact crusher, hammer crusher, roller crusher, compound crusher, double-stage crusher, gyratory crusher, mobile crusher, etc. Fine crushing can be done by column mill, ball mill, high-pressure roller mill, etc.

[0035] During cement hydration, the activated coal gangue early strength mixture and fluidity adjusting material of this embodiment generate high-density CASH gel (hydrated calcium aluminosilicate gel) instead of CSH gel. The aluminates in the activated coal gangue and cement react with CaCO3 in the limestone to generate calcium aluminate. The presence of calcite in the limestone helps to maintain the AFt (ettringite) phase formed in the early stage of the hydration process. In addition, the reaction of the active silica and alumina in the activated coal gangue and the generation of aluminate consume a large amount of Ca(OH)2, accelerating the hydration of tricalcium silicate (3CaO·SiO2). At the same time, the active components of silica and alumina in the coal gangue are stimulated to form hydrated calcium silicate with dominant strength and hydrated calcium aluminate with drought strength.

[0036] Example 2

[0037] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0038] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 900℃ for 3h, and cooled to room temperature. The main chemical composition of the coal gangue used includes: SiO2 54.6%, Al2O3 15.8%, Fe2O35.8%, CaO 3.7%, MgO 1.8%, SO3 0.3%, K2O 1%, Na2O 1.1%, and loss on ignition 15.9%;

[0039] The calcined activated material was ground with a ball mill to a specific surface area of ​​600 m 2 / kg, forming activated coal gangue material;

[0040] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​500m 2 / kg, forming active limestone material, the main chemical composition of the limestone used includes: SiO2 10%, Al2O3 2.06%, Fe2O3 1.88%, CaO45.9%, MgO 2.43%, ignition loss 36%;

[0041] Add active limestone according to 5% of the mass of activated coal gangue, and mix and homogenize in a ball mill for 20 minutes;

[0042] The mixed and ground materials are put into an aging bin and aged for 12 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0043] The gangue cement binder was prepared according to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjustment material = 7:3, and its 3-day mortar strength and 3-day activity index (H3 = R3d Gangue / R 3d Cement × 100) and fluidity. The activity detection method of activated coal gangue early strength mixture and fluidity adjustment material refers to GB / T1596-2017, and is specifically calculated using the following formula:

[0044] H = R gangue / R cement × 100;

[0045] Wherein, H is the strength activity index of the test sample (%), R gangue is the compressive strength of activated coal gangue mortar (MPa), and R cement is the compressive strength of cement mortar (MPa).

[0046] As shown in Table 1, the 3-day compressive strength of the activated coal gangue early strength mixture and fluidity adjustment material of this embodiment reaches 26.5 MPa, the 3-day activity reaches 80%, the initial fluidity reaches 152, and the time-dependent fluidity reaches 125.

[0047] Table 1 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 2

[0048]

[0049] Example 3

[0050] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0051] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 600℃ for 6 hours, and cooled to room temperature. The main chemical composition of the coal gangue used includes: SiO2 59.9%, Al2O3 21%, Fe2O33.5%, CaO 1%, MgO 0.3%, SO3 2.4%, K2O 2%, Na2O 1.8%, and loss on ignition 8%;

[0052] The calcined activated material was ground with a ball mill to a specific surface area of ​​650 m 2 / kg, forming activated coal gangue material;

[0053] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​550m 2 / kg, forming active limestone material, the main chemical composition of the limestone used includes: SiO2 1.18%, Al2O3 2.5%, Fe2O3 1.58%, CaO53%, MgO 0.14%, ignition loss 41.6%;

[0054] Add activated limestone according to 10% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 15 minutes;

[0055] The mixed and ground materials are put into the aging bin and aged for 18 hours to form the activated coal gangue early strength mixture and fluidity adjustment material.

[0056] The gangue cement binder was prepared according to the mass ratio of cement: active gangue early strength mixture and fluidity adjusting material = 7:3 and its properties were measured. As shown in Table 2, the 3-day compressive strength reached 26.8MPa, the 3-day activity reached 81%, the initial fluidity reached 155, and the time-dependent fluidity reached 136.

[0057] Table 2 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 3

[0058]

[0059] Example 4

[0060] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0061] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 750℃ for 5h, and cooled to room temperature. The main chemical composition of the coal gangue used includes: SiO2 45.43%, Al2O3 22.95%, Fe2O31.97%, CaO 2.53%, MgO 0.4%, SO3 2.03%, K2O 1.3%, Na2O 1.39%, and loss on ignition 22%;

[0062] The calcined activated material was ground with a ball mill to a specific surface area of ​​780 m 2 / kg, forming activated coal gangue material;

[0063] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​560m 2 / kg, forming active limestone material, the main chemical composition of the limestone used includes: SiO2 4.4%, Al2O3 0.95%, Fe2O3 2%, CaO 51.3%, MgO 1.3%, and ignition loss of 40%;

[0064] Add activated limestone material according to 15% of the weight of activated coal gangue material, and mix and homogenize in a ball mill for 20 minutes;

[0065] The mixed and ground materials are put into an aging bin and aged for 24 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0066] The gangue cement binder was prepared according to the mass ratio of cement: active gangue early strength mixture and fluidity adjusting material = 7:3 and its properties were measured. As shown in Table 3, the 3-day compressive strength reached 27.5MPa, the 3-day activity reached 83%, the initial fluidity reached 158, and the time-dependent fluidity reached 137.

[0067] Table 3 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 4

[0068]

[0069] Example 5

[0070] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0071] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 780℃ for 4h, and cooled to room temperature. The main chemical composition of the coal gangue used includes: SiO2 54.26%, Al2O3 20.38%, Fe2O33.6%, CaO 3.77%, MgO 0.21%, SO3 0.1%, K2O 2.0%, Na2O 1%, and the loss on ignition is 14.40%;

[0072] The calcined activated material was ground with a ball mill to a specific surface area of ​​800 m 2 / kg, forming activated coal gangue material;

[0073] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​560m 2 / kg, forming active limestone material, the main chemical composition of the limestone used includes: SiO2 0.2%, Al2O3 0.86%, Fe2O3 0.1%, CaO 55%, MgO 0.76%, and the ignition loss is 43%;

[0074] Add activated limestone according to 30% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 15 minutes;

[0075] The mixed and ground materials are put into an aging bin and aged for 20 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0076] According to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjusting material = 7:3, coal gangue cement binder was prepared and its properties were measured. As shown in Table 4, the 3-day compressive strength reached 29.5MPa, the 3-day activity reached 89%, the initial fluidity reached 196, and the time-dependent fluidity reached 170.

[0077] Table 4 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 5

[0078]

[0079] Example 6

[0080] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0081] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 800℃ for 6h, and cooled to room temperature. The main chemical composition of the coal gangue used is: SiO2 52.56%, Al2O3 20.43%, Fe2O35.73%, CaO 1.37%, MgO 0.1%, SO3 0.60%, K2O 1.7%, Na2O 1.13%, and the loss on ignition is 16.13%;

[0082] The calcined activated material was ground with a ball mill to a specific surface area of ​​900 m 2 / kg, forming activated coal gangue material;

[0083] The limestone is dried, cleaned of mud, sand and other impurities, and then crushed to a specific surface area of ​​580m 2 / kg, forming active limestone material, the main chemical composition of the limestone used is: SiO2 1.9%, Al2O3 0.2%, Fe2O3 1.58%, CaO 53.5%, MgO 0.74%, and the loss on ignition is 42%;

[0084] Add activated limestone according to 50% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 10 minutes;

[0085] The mixed and ground materials are put into an aging bin and aged for 24 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0086] According to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjusting material = 7:3, coal gangue cement binder was prepared and its properties were measured. As shown in Table 5, the 3-day compressive strength reached 31.4MPa, the 3-day activity reached 95%, the initial fluidity reached 221, and the time-dependent fluidity reached 201.

[0087] Table 5 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 6

[0088]

[0089] Example 7

[0090] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0091] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 800℃ for 6h, and cooled to room temperature. The main chemical composition of the coal gangue used is: SiO2 30.61%, Al2O3 21.2%, Fe2O310%, CaO 6%, MgO 3%, SO3 3.92%, K2O 1.67%, Na2O 2.0%, and the loss on ignition is 21.58%;

[0092] The calcined activated material was ground with a ball mill to a specific surface area of ​​1000m 2 / kg, forming activated coal gangue material;

[0093] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​600m 2 / kg, forming active limestone material, the main chemical composition of the limestone used is: SiO2 0.2%, Al2O3 0.86%, Fe2O3 0.1%, CaO 55%, MgO0.76%, and the ignition loss is 43%;

[0094] Add activated limestone according to 50% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 10 minutes;

[0095] The mixed and ground materials are put into an aging bin and aged for 24 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0096] According to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjusting material = 7:3, coal gangue cement binder was prepared and its properties were measured. As shown in Table 6, the 3-day compressive strength reached 31.1 MPa, the 3-day activity reached 94%, the initial fluidity reached 219, and the time-dependent fluidity reached 196.

[0097] Table 6 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 7

[0098]

[0099] Example 8

[0100] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0101] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 800℃ for 6h, and cooled to room temperature. The main chemical composition of the coal gangue used is: SiO2 50.3%, Al2O3 32.20%, Fe2O32.66%, CaO 1.1%, MgO 1.5%, SO3 0.80%, K2O 0.7%, Na2O 0.5%, and the loss on ignition is 10.1%;

[0102] The calcined activated material was ground with a ball mill to a specific surface area of ​​900 m 2 / kg, forming activated coal gangue material;

[0103] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​600m 2 / kg, forming active limestone material, the main chemical composition of the limestone used is: SiO2 0.2%, Al2O3 0.86%, Fe2O3 0.1%, CaO 55%, MgO0.76%, and the ignition loss is 43%;

[0104] Add activated limestone according to 50% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 10 minutes;

[0105] The mixed and ground materials are put into an aging bin and aged for 24 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0106] According to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjusting material = 7:3, coal gangue cement binder was prepared and its properties were measured. As shown in Table 7, the 3-day compressive strength reached 30.7MPa, the 3-day activity reached 93%, the initial fluidity reached 218, and the time-dependent fluidity reached 194.

[0107] Table 7 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 8

[0108]

[0109] Example 9

[0110] A method for preparing an activated coal gangue early strength mixture and a fluidity adjusting material comprises the following steps:

[0111] The selected coal gangue is crushed by jaw crusher to a particle size of less than or equal to 20mm, crushed by hammer crusher to 3-5mm, and finely crushed by ball mill to a particle size of less than or equal to 1mm, and then calcined in a calcining kiln at a calcination temperature of 800℃ for 6 hours, and cooled to room temperature. The main chemical composition of the coal gangue used is: SiO2 56%, Al2O3 12.9%, Fe2O3 5.8%, CaO 4.5%, MgO 1.9%, SO3 0.5%, K2O 0.8%, Na2O 1.0%, and the loss on ignition is 16.5%;

[0112] The calcined activated material was ground with a ball mill to a specific surface area of ​​900 m 2 / kg, forming activated coal gangue material;

[0113] The limestone is dried, cleaned of impurities such as mud and sand, and then crushed to a specific surface area of ​​600m 2 / kg, forming active limestone; the main chemical composition of the limestone used is: SiO2 0.2%, Al2O3 0.86%, Fe2O3 0.1%, CaO 55%, MgO0.76%, and the ignition loss is 43%;

[0114] Add activated limestone according to 50% of the weight of activated coal gangue, and mix and homogenize in a ball mill for 20 minutes;

[0115] The mixed and ground materials are put into an aging bin and aged for 20 hours to form coal gangue active coal gangue early strength mixture and fluidity adjustment material.

[0116] According to the mass ratio of cement: active coal gangue early strength mixture and fluidity adjusting material = 7:3, coal gangue cement binder was prepared and its properties were measured. As shown in Table 8, the 3-day compressive strength reached 22.4MPa, the 3-day activity was 68%, the initial fluidity reached 218, and the time-dependent fluidity reached 195.

[0117] Table 8 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 9

[0118]

[0119] Example 10

[0120] The difference between this embodiment and embodiment 6 is that the calcined activated material is ground by a ball mill to a specific surface area of ​​800 m 2 / kg, forming activated coal gangue material.

[0121] The gangue cement binder was prepared according to the mass ratio of cement: activated gangue material = 7:3, without adding limestone, and its properties were measured. As shown in Table 9, the 3-day compressive strength was 23.2 MPa, the 3-day activity was 70%, the initial fluidity was 119, and the fluidity over time was non-flowing.

[0122] Table 9 Performance data of activated coal gangue prepared in Example 10

[0123]

[0124] Embodiment 11

[0125] The difference between this embodiment and embodiment 6 is that the calcined activated material is ground by a ball mill to a specific surface area of ​​600 m 2 / kg, forming activated coal gangue material.

[0126] The gangue cement binder was prepared according to the mass ratio of cement: activated gangue material = 7:3, without adding limestone, and its properties were measured. As shown in Table 10, the 3-day compressive strength was 22.9 MPa, the 3-day activity was 69%, the initial fluidity was 122, and the fluidity over time was non-flowing.

[0127] Table 10 Performance data of activated coal gangue prepared in Example 11

[0128]

[0129] Example 12

[0130] This embodiment is different from Embodiment 6 in that the gangue cement cementitious material is prepared according to the mass ratio of cement: activated gangue early strength mixture and fluidity adjusting material = 5:5, and its properties are shown in Table 11. The 3-day compressive strength is 22.5 MPa, the 3-day activity is 68%, the initial fluidity is 216, and the time-dependent fluidity is 206.

[0131] Table 11 Performance data of activated coal gangue early strength mixture and fluidity adjustment material prepared in Example 12

[0132]

[0133] It can be seen from Tables 1 to 7 that after adding limestone active material, the 3-day strength (increased by 30-50%), 3-day activity (increased to 80-95%) and fluidity of the activated coal gangue material are greatly improved. The mass ratio of Al2O3 to SiO2 in coal gangue in Example 9 is 0.23, which is less than 0.28, and the 3-day and 28-day activities are significantly reduced. Example 10 uses activated coal gangue with a specific surface area of ​​800m 2 / kg, no limestone is added, and Example 11 uses activated coal gangue with a specific surface area of ​​600m 2 / kg, no limestone added, no fluidity over time, and reduced strength and activity after 3 days. In Example 12, when the active coal gangue early strength mixture and fluidity adjustment material are added in an amount of 50%, the performance meets the national standard PC42.5 requirements.

[0134] The activated coal gangue early strength mixture and fluidity adjusting material prepared in the embodiment of the present invention are suitable for cement admixtures with high early strength requirements. In order to obtain higher early strength, an early strength agent is generally added. Chemical early strength agents are prone to cause alkali aggregate reaction, steel corrosion, and long-term strength shrinkage, which affect the durability of concrete. The present invention adopts inorganic materials that can not only form high-activity cement early strength admixtures but also do not affect the later strength and durability of cement. Usually, the addition of activated admixtures seriously affects the fluidity of cement. Generally, the treatment method is to reduce the dosage or reduce the fineness of the admixture, reduce the activity of the mixture, and reduce the overall admixture dosage. The method of the embodiment of the present invention is simple and is suitable for industries such as cement and wall materials. If used as a cement admixture, its addition amount is not less than 20%, and the cement properties such as strength, fluidity, and setting time of cement grades PC42.5 and PC52.5 are normal. At present, the cost of one ton of clinker is about 200-260 yuan. Among the current cement additives, the market price of granulated blast furnace slag active mineral powder is about 400 yuan per ton, active fly ash is about 100-120 yuan per ton, and kaolin is more than 300 yuan per ton. Coal gangue containing 98% kaolin is a kaolin resource. The embodiment of the present invention fully utilizes inferior coal gangue solid waste raw materials. Since the treatment method of the embodiment of the present invention is simple, the treatment cost of one ton of coal gangue is only tens of yuan, which will greatly reduce the cost of cement. And it can effectively save resources such as slag and fly ash. The carbon dioxide emission of each ton of cement clinker is 860kg. If 20% of the clinker is replaced, the carbon emission can be reduced by 172kg per ton. The annual production line of 1 million tons of clinker can reduce carbon dioxide emissions by 172,000 tons. According to the current market trading price, the carbon sink transaction is about 8-9 million. Taking the replacement of granulated blast furnace slag as an example, the cost of cement per ton will be reduced by 15-20 yuan. A small cement plant with an annual output of 1 million tons can increase its net profit by 15-20 million yuan per year. my country's coal mines are widely distributed and cement plants are spread all over the country. This will bring considerable economic benefits to cement plants. In addition, the large-scale use of coal gangue can effectively control environmental pollution, free up or reduce the occupation of a large amount of farmland, and have good social benefits.

[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. An activated coal gangue early strength mixture, characterized in that: Contains activated coal gangue material and active high calcium material; The active high calcium material is active limestone, and the active limestone is 50% of the mass of the activated coal gangue material; The specific surface area of ​​the activated gangue material is 900m 2 / kg, the specific surface area of ​​the active high calcium material is 500-600m 2 / kg; The activated coal gangue material is formed by crushing coal gangue and then calcining and activating it at high temperature; Among them, the coal gangue is selected to be clay coal gangue with a mass ratio of Al2O3 to SiO2 greater than or equal to 0.28, and the mass percentage of CaO in the high calcium raw material is greater than or equal to 45%; The chemical composition of the clayey coal gangue includes: SiO2 30-60%, Al2O3 12-33%, Fe2O3 1.9-10%, CaO 1-6%, MgO 0.1-3%, SO3 0.1-4%, K2O 0.7-2%, Na2O 0.5-2%, the loss on ignition is 8-22%, and the remaining components are trace elements, and the total mass percentage is 100%; The active high calcium material is formed by drying the high calcium raw material, removing surface impurities and then crushing it; The chemical composition of the high-calcium raw material includes: SiO2 0.2-10%, Al2O3 0.2-2.5%, Fe2O3 0.1-2%, CaO 45-55%, MgO 0.1-2.5%, the loss on ignition is 36-43%, and the remaining components are trace elements, and the total mass percentage is 100%.

2. The activated coal gangue early strength mixture according to claim 1, characterized in that: As cement admixture, it is used to prepare PC42.5 and PC52.5 cement.

3. The method for preparing an activated coal gangue early strength mixture according to any one of claims 1 to 2, characterized in that: The following steps are involved: After selecting the coal gangue, it is first crushed, and then the coal gangue is calcined and activated at high temperature to form calcined activated material; Finely crushing and activating the calcined activated material to form activated coal gangue material; The high calcium raw material is dried, surface impurities are removed and then crushed to form active high calcium material; Add active high calcium material according to 50% of the mass of activated coal gangue material and mix and grind to homogenize; The mixed and ground materials are put into the aging bin for aging to form an activated coal gangue early strength mixture.

4. The method for preparing an activated coal gangue early strength mixture according to claim 3, characterized in that: After being crushed, the gangue is calcined at 600-900°C for 3-6 hours to form a calcined activated material.

5. The method for preparing an activated coal gangue early strength mixture according to claim 3, characterized in that: After mixing, the mixture is homogenized in a ball mill for 10 to 20 minutes, and the mixed material is aged in an aging bin for 12 to 24 hours to form an activated coal gangue early strength mixture.

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