A modified caving stone powder for preparing concrete and its preparation process

Abstract

This invention provides a modified slag aggregate powder for preparing concrete and its preparation process. The preparation process of the modified slag aggregate powder for concrete includes the following steps: preliminary ball milling of the slag aggregate powder, dilution with hydrochloric acid and acid leaching activation, dilution of an aluminate coupling agent and primary surface modification, secondary surface modification, addition of calcium sulfate whiskers, centrifugal spray drying, and collection of the modified slag aggregate powder. This invention utilizes an aluminate coupling agent and a silane coupling agent to composite modify the slag aggregate powder, thereby effectively improving the bonding strength of the slag aggregate powder. Concrete prepared using this composite-modified slag aggregate powder as one of the raw materials exhibits good cohesiveness and strong impact resistance after drying.

Description

Technical Field

[0001] This invention relates to the field of concrete, and more specifically to a modified slag powder for preparing concrete and its preparation process. Background Technology

[0002] Tramstone powder is waste dust with a particle size of less than 75μm generated during the production of manufactured sand. Therefore, it is necessary to utilize tramstone powder to reduce environmental pollution.

[0003] Because of the large quantity and low cost of slag powder, there is currently a practice of adding slag powder to concrete to utilize the waste. However, since slag powder is an inert material with low bonding strength, it cannot react with cement to form a gel. Ordinary slag powder directly added to concrete can only serve as a filler. Furthermore, because the amount of slag powder added is difficult to control, excessive addition can easily lead to reduced cohesion and impact resistance of the concrete, making it prone to collapse.

[0004] Therefore, we propose a modified slag powder with high bonding strength for the preparation of concrete to improve the cohesiveness and impact resistance of concrete. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a modified slag powder for preparing concrete and its preparation process.

[0006] A process for preparing modified caving aggregate powder for concrete includes the following steps:

[0007] S1: Preliminary ball milling of travertine powder

[0008] Place the slag stone powder in a ball mill, adjust the ball mill speed to 40-80 rpm, and ball mill for 1-2 hours to obtain coarse ground stone powder;

[0009] S2: Dilute hydrochloric acid and activate by acid leaching.

[0010] Hydrochloric acid was diluted in heated deionized water, and then the coarsely ground stone powder was added. The mixture was stirred and mixed, and after being kept warm and activated, it was washed, filtered and dried to obtain activated stone powder.

[0011] S3: Dilute the aluminate coupling agent and perform a surface modification.

[0012] The aluminate coupling agent is diluted and dispersed in dimethyl sulfoxide, and then evenly sprayed onto the surface of the activated stone powder to perform a first-time surface modification, thereby obtaining a first-time modified stone powder.

[0013] S4: Secondary surface modification with the addition of calcium sulfate whiskers

[0014] Mix the silane coupling agent with deionized water, then add the above-mentioned first-modified stone powder for second-modification, then add calcium sulfate whiskers and ball mill to obtain modified stone powder slurry.

[0015] S5: Centrifugal spray drying and collection of modified travertine powder

[0016] The modified stone powder slurry was centrifuged and atomized into modified stone powder droplets, which were then brought into full contact with purified and heated air to dry the modified stone powder droplets, thus obtaining modified quarry stone powder, which was then collected.

[0017] Further, step S2, which involves diluting hydrochloric acid and activating it through acid leaching, specifically includes the following steps:

[0018] S2.1: Add deionized water to the reactor, turn on the heater, and heat the deionized water to 40-50℃;

[0019] S2.2: Hydrochloric acid is pumped into the reactor at a constant rate using a hydraulic pump until the online hydrochloric acid concentration meter in the reactor detects a concentration of 3-6%, at which point the online hydrochloric acid concentration meter sends a signal to the controller.

[0020] S2.3: After receiving the signal from the online hydrochloric acid concentration meter, the controller controls the hydraulic pump to shut down and simultaneously controls the feeding assembly to open;

[0021] S2.4: The coarse grinding stone powder is added to the reactor through the feeding assembly. After the first gravity sensor in the reactor detects the addition of the coarse grinding stone powder, the first gravity sensor sends a signal to the controller.

[0022] S2.5: After receiving the signal sent by the first gravity sensor, the controller controls the first stirrer in the reactor to stir at a rate of 300-400 r / min for 20-35 min;

[0023] S2.6: Let stand for 1-3 hours for heat preservation and activation, then drain the liquid in the reactor, add deionized water to the reactor, and wash with water to obtain a water-washed suspension.

[0024] S2.7: The above-mentioned water-washed suspension is filtered by the pressure filter assembly in the reactor. After the filtrate is discharged, hot air is introduced into the reactor to dry the filter residue and obtain activated stone powder.

[0025] Further, step S3 involves diluting the aluminate coupling agent and performing a surface modification, specifically including the following steps:

[0026] S3.1: Add the aluminate coupling agent and dimethyl sulfoxide together into the spray can, mix them evenly by vibration, and obtain the coupling agent dilution solution;

[0027] S3.2: The above-mentioned coupling agent dilution is atomized into droplets by the atomizer of the spray can and evenly sprayed onto the surface of the above-mentioned activated stone powder to perform a surface modification and obtain modified stone powder.

[0028] Furthermore, the secondary surface modification and addition of calcium sulfate whiskers in step S4 specifically includes the following steps:

[0029] S4.1: Add silane coupling agent and deionized water to the ball mill at a volume ratio of 1-2:40-53, and then mix them by stirring with a second stirrer;

[0030] S4.2: Add the above-mentioned primary modified stone powder into a ball mill, adjust the ball mill speed to 200-280 rpm, and ball mill for 0.5-1.5 h to carry out secondary surface modification;

[0031] S4.3: Add calcium sulfate whiskers to a ball mill, adjust the ball mill speed to 100-120 rpm, and continue ball milling for 1-2 hours to obtain modified stone powder slurry.

[0032] Further, step S5, centrifugal spray drying and collection of modified cavitary stone powder, specifically includes the following steps:

[0033] S5.1: Air is drawn into the air handling chamber of the drying chamber by an air extractor. The air is purified by a purifier, then heated to 90-120°C by a heater, and finally enters the air distributor at the top of the drying chamber. The air distributor circulates the heated air into the drying chamber of the drying chamber.

[0034] S5.2: Add the above modified stone powder slurry to the centrifugal atomizer at the top of the drying chamber to centrifuge and atomize the modified stone powder slurry into modified stone powder droplets;

[0035] S5.3: The modified stone powder droplets come into full contact with hot air in the drying chamber, and the moisture in the modified stone powder droplets is rapidly evaporated and dried to obtain modified slag stone powder.

[0036] S5.4: The modified slag powder is separated by the separator at the bottom of the drying box and sent to the collection box. When the second gravity sensor in the collection box detects the entry of the modified slag powder, the second gravity sensor sends a signal to the controller.

[0037] S5.5: After receiving the signal sent by the second gravity sensor, the controller controls the exhaust fan in the drying chamber to start, so as to expel the hot air from the drying chamber.

[0038] Furthermore, after receiving the signal sent by the second gravity sensor, the controller controls the exhaust fan in the drying chamber to start. The exhaust fan discharges the hot air in the drying chamber into the reactor in step S2.7 through the air guide pipe to dry the activated stone powder in the reactor.

[0039] Furthermore, the aluminate coupling agent is one of SG-Al821, DL-411, and DL-411F.

[0040] Furthermore, the silane coupling agent is one of A171, KH-151, and SCA-1502.

[0041] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0042] 1. This invention utilizes aluminate coupling agent and silane coupling agent to composite modify slag powder, thereby effectively improving the bonding strength of slag powder. Concrete prepared using this composite modified slag powder as one of the raw materials has good cohesiveness, and the concrete has strong impact resistance after drying.

[0043] 2. The composite stone powder prepared by adding calcium sulfate whiskers has good corrosion resistance and high tensile strength. Adding this composite stone powder can effectively improve the tensile strength and elastic modulus of concrete.

[0044] 3. The present invention first performs preliminary ball milling on the slag powder to reduce the sharp edges on the surface of the slag powder particles, which facilitates subsequent surface modification. Then, it performs ball milling again by increasing the ball milling speed to make the slag powder particles finer, thereby increasing the fluidity of concrete made from the slag powder.

[0045] 4. This invention utilizes diluted hydrochloric acid to soak the pre-milled karst stone powder, thereby activating the karst stone powder, releasing its surface activity, and achieving the effect of improving the efficiency of subsequent surface modification reactions. Attached Figure Description

[0046] Figure 1 This is a flow chart of the preparation process of modified slag powder for concrete preparation used in the embodiments of the present invention. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to specific embodiments.

[0048] Example 1

[0049] A process for preparing modified slag powder for concrete, such as... Figure 1 As shown, it includes the following steps:

[0050] S1: Preliminary ball milling of travertine powder

[0051] Place the slag stone powder in a ball mill, adjust the ball mill speed to 40 rpm, and ball mill for 1 hour to obtain coarse ground stone powder. By first ball milling the slag stone powder, the sharp edges on the surface of the slag stone powder particles are reduced, which facilitates the subsequent surface modification.

[0052] S2: Dilute hydrochloric acid and activate by acid leaching.

[0053] Deionized water is added to the reactor, and the heater is turned on to heat the deionized water to 40°C. Then, hydrochloric acid is pumped into the reactor at a constant rate using a hydraulic pump until the online hydrochloric acid concentration meter detects a concentration of 3%. At this point, the online concentration meter sends a signal to the controller. Upon receiving the signal, the controller shuts off the hydraulic pump and simultaneously opens the feeding assembly, allowing the coarse ground stone powder to be added to the reactor. Once the first gravity sensor in the reactor detects the addition of the coarse ground stone powder, it sends a signal to the controller. Upon receiving this signal, the controller... After that, the first stirrer in the reactor is stirred at a rate of 300 r / min for 20 min, and then left to stand for 1 h for heat preservation and activation. Then, the liquid in the reactor is discharged, and deionized water is added to the reactor for washing to obtain a water-washed suspension. Finally, the water-washed suspension is filtered by the pressure filter assembly in the reactor. After the filtrate is discharged, hot air is introduced into the reactor to dry the filter residue to obtain activated stone powder. The pre-ball-milled travertine powder is then soaked in diluted hydrochloric acid to activate it and release its surface activity, thereby improving the efficiency of subsequent surface modification reactions.

[0054] S3: Dilute the aluminate coupling agent and perform a surface modification.

[0055] DL-411F aluminate coupling agent and dimethyl sulfoxide were added to a spray can and mixed evenly by vibration to obtain a coupling agent dilution. The above coupling agent dilution was atomized into droplets by the atomizer of the spray can and evenly sprayed onto the surface of the activated stone powder to perform a first surface modification and obtain a first modified stone powder.

[0056] S4: Secondary surface modification with the addition of calcium sulfate whiskers

[0057] SCA-1502 silane coupling agent and deionized water were added to a ball mill at a volume ratio of 1:40 and mixed using a second agitator. Then, the previously modified stone powder was added to the ball mill, and the mill speed was adjusted to 200 rpm for 0.5 hours for secondary surface modification. A second milling process was performed by increasing the mill speed to further refine the slag stone powder particles, thereby increasing the fluidity of concrete made from this slag stone powder. Finally, calcium sulfate whiskers were added to the ball mill, and the mill speed was adjusted to 100 rpm for continued milling. After grinding for 1 hour, a modified stone powder slurry was obtained. By using aluminate coupling agent and silane coupling agent to modify the slag stone powder, the bonding strength of the slag stone powder can be effectively improved. The concrete prepared by using the modified slag stone powder as one of the raw materials has good cohesiveness and strong impact resistance after drying. In addition, the composite stone powder prepared by adding calcium sulfate whiskers has good corrosion resistance and high tensile strength. Adding this composite stone powder can effectively improve the tensile strength and elastic modulus of concrete.

[0058] S5: Centrifugal spray drying and collection of modified travertine powder

[0059] Air is drawn into the air handling chamber of the drying chamber by an air extractor. The air is purified by a purifier, heated to 90°C by a heater, and then enters the air distributor at the top of the drying chamber. The air distributor circulates the heated air into the drying chamber. The modified stone powder slurry is then added to the centrifugal atomizer at the top of the drying chamber, centrifugally atomizing the slurry into modified stone powder droplets. The modified stone powder droplets come into full contact with the hot air in the drying chamber, rapidly evaporating the moisture and drying the powder to obtain modified slag stone powder. The modified slag stone powder is then separated by a separator at the bottom of the drying chamber and sent to a collection box. When the second gravity sensor in the collection box detects the entry of the modified slag stone powder, it sends a signal to the controller. Upon receiving the signal, the controller activates the exhaust fan in the drying chamber. The exhaust fan discharges the hot air from the drying chamber into the reactor in step S2 through an air duct to dry the activated stone powder in the reactor.

[0060] Example 2

[0061] A process for preparing modified slag powder for concrete, such as... Figure 1 As shown, it includes the following steps:

[0062] S1: Preliminary ball milling of travertine powder

[0063] The slag stone powder was placed in a ball mill, the ball mill speed was adjusted to 80 rpm, and the ball mill was milled for 1 hour to obtain coarse ground stone powder. By first performing preliminary ball milling on the slag stone powder, the sharp edges on the surface of the slag stone powder particles are reduced, which facilitates the subsequent surface modification.

[0064] S2: Dilute hydrochloric acid and activate by acid leaching.

[0065] Deionized water is added to the reactor, and the heater is turned on to heat the deionized water to 50°C. Then, hydrochloric acid is pumped into the reactor at a constant rate using a hydraulic pump until the online hydrochloric acid concentration meter detects a concentration of 3%. At this point, the online concentration meter sends a signal to the controller. Upon receiving the signal, the controller shuts off the hydraulic pump and simultaneously opens the feeding assembly, allowing the coarse ground stone powder to be added to the reactor. Once the first gravity sensor in the reactor detects the addition of the coarse ground stone powder, it sends a signal to the controller. Upon receiving this signal, the controller... After that, the first stirrer in the reactor is stirred at a rate of 400 r / min for 20 min, and then left to stand for 1 h for heat preservation and activation. Then, the liquid in the reactor is discharged, and deionized water is added to the reactor for washing to obtain a water-washed suspension. Finally, the water-washed suspension is filtered by the pressure filter assembly in the reactor. After the filtrate is discharged, hot air is introduced into the reactor to dry the filter residue to obtain activated stone powder. The pre-ball-milled travertine powder is then soaked in diluted hydrochloric acid to activate it and release its surface activity, thereby improving the efficiency of subsequent surface modification reactions.

[0066] S3: Dilute the aluminate coupling agent and perform a surface modification.

[0067] DL-411 aluminate coupling agent and dimethyl sulfoxide are added to a spray can and mixed evenly by vibration to obtain a coupling agent dilution. The above coupling agent dilution is atomized into droplets by the atomizer of the spray can and evenly sprayed onto the surface of the above activated stone powder to perform a first surface modification to obtain a first modified stone powder.

[0068] S4: Secondary surface modification with the addition of calcium sulfate whiskers

[0069] KH-151 silane coupling agent and deionized water were added to a ball mill at a volume ratio of 2:53 and mixed using a second agitator. Then, the previously modified stone powder was added to the ball mill, and the mill speed was adjusted to 200 rpm for 0.5 hours for secondary surface modification. A second milling process was performed by increasing the mill speed to further refine the slag stone powder particles, thereby increasing the fluidity of concrete made from this slag stone powder. Finally, calcium sulfate whiskers were added to the ball mill, and the mill speed was adjusted to 100 rpm for continued milling. After 1 hour, a modified stone powder slurry was obtained. By using aluminate coupling agent and silane coupling agent to modify the slag stone powder, the bonding strength of the slag stone powder can be effectively improved. The concrete prepared by using the modified slag stone powder as one of the raw materials has good cohesiveness and strong impact resistance after drying. In addition, the composite stone powder prepared by adding calcium sulfate whiskers has good corrosion resistance and high tensile strength. Adding this composite stone powder can effectively improve the tensile strength and elastic modulus of concrete.

[0070] S5: Centrifugal spray drying and collection of modified travertine powder

[0071] Air is drawn into the air handling chamber of the drying chamber by an exhaust fan. The air is purified by a purifier, heated to 120°C by a heater, and then enters the air distributor at the top of the drying chamber. The air distributor circulates the heated air into the drying chamber. The modified stone powder slurry is then added to the centrifugal atomizer at the top of the drying chamber, centrifugally atomizing the slurry into modified stone powder droplets. The modified stone powder droplets come into full contact with the hot air in the drying chamber, rapidly evaporating the moisture and drying the powder to obtain modified slag stone powder. The modified slag stone powder is then separated by a separator at the bottom of the drying chamber and sent to a collection box. When the second gravity sensor in the collection box detects the entry of the modified slag stone powder, it sends a signal to the controller. Upon receiving the signal, the controller activates the exhaust fan in the drying chamber. The exhaust fan discharges the hot air from the drying chamber into the reactor in step S2 through an air duct to dry the activated stone powder in the reactor.

[0072] Example 3

[0073] A process for preparing modified slag powder for concrete, such as... Figure 1 As shown, it includes the following steps:

[0074] S1: Preliminary ball milling of travertine powder

[0075] The slag stone powder was placed in a ball mill, the ball mill speed was adjusted to 40 rpm, and the ball mill was milled for 2 hours to obtain coarse ground stone powder. By first performing preliminary ball milling on the slag stone powder, the sharp edges on the surface of the slag stone powder particles are reduced, which facilitates the subsequent surface modification.

[0076] S2: Dilute hydrochloric acid and activate by acid leaching.

[0077] Deionized water is added to the reactor, and the heater is turned on to heat the deionized water to 40°C. Then, hydrochloric acid is pumped into the reactor at a constant rate using a hydraulic pump until the online hydrochloric acid concentration meter detects a concentration of 6%. At this point, the online concentration meter sends a signal to the controller. Upon receiving the signal, the controller shuts off the hydraulic pump and simultaneously opens the feeding assembly, allowing the coarse ground stone powder to be added to the reactor. Once the first gravity sensor in the reactor detects the addition of the coarse ground stone powder, it sends a signal to the controller. Upon receiving this signal, the controller... After that, the first stirrer in the reactor is stirred at a rate of 300 r / min for 35 min, and then left to stand for 1 h for heat preservation and activation. Then, the liquid in the reactor is discharged, and deionized water is added to the reactor for washing to obtain a water-washed suspension. Finally, the water-washed suspension is filtered by the pressure filter assembly in the reactor. After the filtrate is discharged, hot air is introduced into the reactor to dry the filter residue to obtain activated stone powder. The pre-ball-milled travertine powder is then soaked in diluted hydrochloric acid to activate it and release its surface activity, thereby improving the efficiency of subsequent surface modification reactions.

[0078] S3: Dilute the aluminate coupling agent and perform a surface modification.

[0079] SG-Al821 aluminate coupling agent and dimethyl sulfoxide were added together into a spray can and mixed evenly by vibration to obtain a coupling agent dilution. The above coupling agent dilution was atomized into droplets through the atomizer of the spray can and evenly sprayed onto the surface of the above activated stone powder to perform a first surface modification and obtain a first modified stone powder.

[0080] S4: Secondary surface modification with the addition of calcium sulfate whiskers

[0081] A171 silane coupling agent and deionized water were added to a ball mill at a volume ratio of 1:40 and mixed using a second agitator. Then, the previously modified stone powder was added to the ball mill, and the mill speed was adjusted to 280 rpm for milling for 0.5 hours for secondary surface modification. A second milling was performed by increasing the mill speed to further refine the slag stone powder particles, thereby increasing the fluidity of concrete made from this slag stone powder. Finally, calcium sulfate whiskers were added to the ball mill, and the mill speed was adjusted to 120 rpm for milling. h, modified stone powder slurry is obtained. By using aluminate coupling agent and silane coupling agent to composite modify the caving slag stone powder, the bonding strength of the caving slag stone powder can be effectively improved. The concrete prepared by using the composite modified caving slag stone powder as one of the raw materials has good cohesiveness and strong impact resistance after drying. In addition, the composite stone powder prepared by adding calcium sulfate whiskers has good corrosion resistance and high tensile strength. Adding this composite stone powder can effectively improve the tensile strength and elastic modulus of concrete.

[0082] S5: Centrifugal spray drying and collection of modified travertine powder

[0083] Air is drawn into the air handling chamber of the drying chamber by an exhaust fan. The air is purified by a purifier, heated to 100°C by a heater, and then enters the air distributor at the top of the drying chamber. The air distributor circulates the heated air into the drying chamber. The modified stone powder slurry is then added to the centrifugal atomizer at the top of the drying chamber, centrifugally atomizing the slurry into modified stone powder droplets. These droplets come into full contact with the hot air in the drying chamber, rapidly evaporating the moisture and drying the stone powder to obtain modified slag stone powder. The modified slag stone powder is then separated by a separator at the bottom of the drying chamber and sent to a collection box. When the second gravity sensor in the collection box detects the entry of the modified slag stone powder, it sends a signal to the controller. Upon receiving the signal, the controller activates the exhaust fan in the drying chamber. The exhaust fan discharges the hot air from the drying chamber into the reactor in step S2 through an air duct to dry the activated stone powder in the reactor.

[0084] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A process for preparing modified slag powder for concrete, characterized in that, Includes the following steps: S1: Preliminary ball milling of travertine powder Place the slag stone powder in a ball mill, adjust the ball mill speed to 40-80 rpm, and ball mill for 1-2 hours to obtain coarse ground stone powder; S2: Dilute hydrochloric acid and activate by acid leaching. Hydrochloric acid was diluted in heated deionized water, and then the coarsely ground stone powder was added. The mixture was stirred and mixed, and after being kept warm and activated, it was washed, filtered and dried to obtain activated stone powder. S3: Dilute the aluminate coupling agent and perform a surface modification. The aluminate coupling agent is diluted and dispersed in dimethyl sulfoxide, and then evenly sprayed onto the surface of the activated stone powder to perform a first-time surface modification, thereby obtaining a first-time modified stone powder. S4: Secondary surface modification with the addition of calcium sulfate whiskers Mix the silane coupling agent with deionized water, then add the above-mentioned first-modified stone powder for second-modification, then add calcium sulfate whiskers and ball mill to obtain modified stone powder slurry. S5: Centrifugal spray drying and collection of modified travertine powder The modified stone powder slurry was centrifuged and atomized into modified stone powder droplets, which were then brought into full contact with purified and heated air to dry the modified stone powder droplets, thus obtaining modified quarry stone powder, which was then collected.

2. The preparation process of modified slag powder for preparing concrete according to claim 1, characterized in that, Step S2, which involves diluting hydrochloric acid and activating it through acid leaching, specifically includes the following steps: S2.1: Add deionized water to the reactor, turn on the heater, and heat the deionized water to 40-50℃; S2.2: Hydrochloric acid is pumped into the reactor at a constant rate using a hydraulic pump until the online hydrochloric acid concentration meter in the reactor detects a concentration of 3-6%, at which point the online hydrochloric acid concentration meter sends a signal to the controller. S2.3: After receiving the signal from the online hydrochloric acid concentration meter, the controller controls the hydraulic pump to shut down and simultaneously controls the feeding assembly to open; S2.4: The coarse grinding stone powder is added to the reactor through the feeding assembly. After the first gravity sensor in the reactor detects the addition of the coarse grinding stone powder, the first gravity sensor sends a signal to the controller. S2.5: After receiving the signal sent by the first gravity sensor, the controller controls the first stirrer in the reactor to stir at a rate of 300-400 r / min for 20-35 min; S2.6: Let stand for 1-3 hours for heat preservation and activation, then drain the liquid in the reactor, add deionized water to the reactor, and wash with water to obtain a water-washed suspension. S2.7: The above-mentioned water-washed suspension is filtered by the pressure filter assembly in the reactor. After the filtrate is discharged, hot air is introduced into the reactor to dry the filter residue and obtain activated stone powder.

3. The preparation process of modified slag powder for preparing concrete according to claim 1, characterized in that, Step S3 involves diluting the aluminate coupling agent and performing a surface modification, specifically including the following steps: S3.1: Add the aluminate coupling agent and dimethyl sulfoxide together into the spray can, mix them evenly by vibration, and obtain the coupling agent dilution solution; S3.2: The above-mentioned coupling agent dilution is atomized into droplets by the atomizer of the spray can and evenly sprayed onto the surface of the above-mentioned activated stone powder to perform a surface modification and obtain modified stone powder.

4. The preparation process of modified slag powder for preparing concrete according to claim 1, characterized in that, Step S4, the secondary surface modification and addition of calcium sulfate whiskers, specifically includes the following steps: S4.1: Add silane coupling agent and deionized water to the ball mill at a volume ratio of 1-2:40-53, and then mix them by stirring with a second stirrer; S4.2: Add the above-mentioned primary modified stone powder into a ball mill, adjust the ball mill speed to 200-280 rpm, and ball mill for 0.5-1.5 h to carry out secondary surface modification; S4.3: Add calcium sulfate whiskers to a ball mill, adjust the ball mill speed to 100-120 rpm, and continue ball milling for 1-2 hours to obtain modified stone powder slurry.

5. The preparation process of modified slag powder for preparing concrete according to claim 2, characterized in that, Step S5, centrifugal spray drying and collection of modified cavitary stone powder, specifically includes the following steps: S5.1: Air is drawn into the air handling chamber of the drying chamber by an air extractor. The air is purified by a purifier, then heated to 90-120°C by a heater, and finally enters the air distributor at the top of the drying chamber. The air distributor circulates the heated air into the drying chamber of the drying chamber. S5.2: Add the above modified stone powder slurry to the centrifugal atomizer at the top of the drying chamber to centrifuge and atomize the modified stone powder slurry into modified stone powder droplets; S5.3: The modified stone powder droplets come into full contact with hot air in the drying chamber, and the moisture in the modified stone powder droplets is rapidly evaporated and dried to obtain modified slag stone powder. S5.4: The modified slag powder is separated by the separator at the bottom of the drying box and sent to the collection box. When the second gravity sensor in the collection box detects the entry of the modified slag powder, the second gravity sensor sends a signal to the controller. S5.5: After receiving the signal sent by the second gravity sensor, the controller controls the exhaust fan in the drying chamber to start, so as to expel the hot air from the drying chamber.

6. The preparation process of modified slag powder for preparing concrete according to claim 5, characterized in that, After receiving the signal from the second gravity sensor, the controller controls the exhaust fan in the drying chamber to start. The exhaust fan discharges the hot air in the drying chamber into the reactor in step S2.7 through the air guide pipe to dry the activated stone powder in the reactor.

7. The preparation process of modified slag powder for concrete preparation according to claim 3, characterized in that, The aluminate coupling agent is one of SG-Al821, DL-411 and DL-411F.

8. The preparation process of modified slag powder for preparing concrete according to claim 4, characterized in that, The silane coupling agent is one of A171, KH-151 and SCA-1502.

9. A modified slag powder for preparing concrete, characterized in that, It is prepared by the preparation process of modified slag powder for preparing concrete as described in any one of claims 1-8.

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