Steel slag stabilization treatment method and application thereof in preparation of pervious concrete

Abstract

The application discloses a steel slag stabilization treatment method and application thereof in preparation of pervious concrete, and the method comprises the following steps: 1) after the steel slag is crushed, the steel slag is placed in a vacuum drying box for drying; 2) the steel slag after the drying treatment is screened to obtain steel slag in a preset particle size range; 3) the screened steel slag is placed in a constant-temperature water bath kettle at 80-100 DEG C for water bath heating treatment for 4-8h, then taken out and placed in a vacuum drying box for drying; 4) the steel slag treated in the step 3) is placed in a carbonization reaction kettle, vacuumized to-0.1MPa, then CO2 with a purity of 99% is introduced, the carbonization pressure in the reaction kettle is adjusted to 0-0.2MPa, and carbonization treatment is carried out at a carbonization temperature of 40-80 DEG C for 1.5-9.5h to prepare stabilized steel slag; according to the application, the steel slag is boiled and carbonized, and the concrete is coated and carbonized and maintained, so that f-CaO and f-MgO are eliminated, hydration is promoted, and the strength is increased; in addition, the application can protect the environment and save resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete materials and steel slag resource utilization, and particularly relates to a steel slag stabilization treatment method and application thereof in preparation of pervious concrete. BACKGROUND

[0002] In recent years, with the development of China's heavy industry, the output of steel increases year by year. While the steel is produced, a large amount of solid waste called steel slag is discharged. The amount of steel slag accounts for about 15% to 20% of crude steel. If not properly treated, it will pollute the air, water and land.

[0003] Due to the physical and mechanical properties such as wear resistance and hardness of steel slag, which are comparable to natural limestone, and the content of C2S and C3S, it has certain hydration activity and cementitious property, so it can be applied to building materials products. However, the steel slag has the problem of poor volume stability, which can cause cracking of concrete in later period. The main reason is that f-CaO and f-MgO exist in steel slag, which leads to expansion and cracking of concrete when water is encountered, which limits the application of steel slag in concrete. On the other hand, with the global temperature rising, extreme weather occurs frequently, and the urban waterlogging problem is serious in summer. The road density is high and the water permeability is poor. If the stabilized steel slag can be applied to the road pervious concrete, it has positive practical significance in solid waste resource utilization and environmental protection. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a steel slag stabilization treatment method which is reliable, simple in process and can realize resource utilization of steel slag, and application thereof in preparation of pervious concrete.

[0005] In order to achieve the above technical purpose, the technical scheme adopted by the present application is:

[0006] A steel slag stabilization treatment method, comprising:

[0007] (1) crushing the steel slag and then placing it in a vacuum drying oven for drying, the drying temperature is 100-110 DEG C, and the drying time is 1-1.5 h;

[0008] (2) screening the steel slag after drying treatment to obtain steel slag within a predetermined particle size range;

[0009] (3) placing the screened steel slag in a constant temperature water bath pot at 80-100 DEG C for water bath heating treatment for 4-8 h, then taking it out and placing it in a vacuum drying oven for drying at a temperature of 110-120 DEG C, and the drying time is 1-3 h;

[0010] (4) the steel slag treated in step (3) is placed in a carbonization reactor, vacuumized to -0.1 MPa, then CO2 with a purity of 99% is introduced, the carbonization pressure in the reactor is adjusted to 0-0.2 MPa, and carbonization treatment is carried out at a carbonization temperature of 40-80 ℃ for 1.5-9.5 h to obtain the stabilized steel slag treated by stabilization.

[0011] As a possible implementation, further, in step (1) of the present scheme, when the particle size range of the broken steel slag is 2.36-4.75 mm or 4.75-9.5 mm, drying is carried out at 100 ℃ for 1 h.

[0012] When the particle size range of the steel slag is 9.5-13.2 mm or 13.2-16 mm or 16-19 mm, drying is carried out at 110 ℃ for 1.5 h.

[0013] As a preferred alternative implementation, preferably, in step (2) of the present scheme, the particle size of the obtained steel slag is in the range of 2.36-4.75 mm, 4.75-9.5 mm, 9.5-13.2 mm, 13.2-16 mm, or 16-19 mm.

[0014] As a preferred alternative implementation, preferably, in step (3) of the present scheme, the temperature of water bath heating is 80 ℃, and the heating time is 4, 6 or 8 h.

[0015] As a preferred alternative implementation, preferably, in step (3) of the present scheme, when the particle size range of the steel slag is 2.36-4.75 mm, drying is carried out at 110 ℃ for 1 h.

[0016] When the particle size range of the steel slag is 4.75-9.5 mm, drying is carried out at 110 ℃ for 1.5 h.

[0017] When the particle size range of the steel slag is 9.5-13.2 mm, drying is carried out at 110 ℃ for 2 h.

[0018] When the particle size range of the steel slag is 13.2-16 mm, drying is carried out at 115 ℃ for 2.5 h.

[0019] When the particle size range of the steel slag is 16-19 mm, drying is carried out at 120 ℃ for 3 h.

[0020] Based on the above, the present application also provides the use of the stabilized steel slag prepared by the steel slag stabilization treatment method described above in the preparation of pervious concrete, wherein the prepared stabilized steel slag is added to the concrete formula as coarse aggregate to prepare the pervious concrete.

[0021] As a preferred selection embodiment, preferably, the concrete formula in the scheme comprises: stabilized steel slag, P·O4 2.5 cement, mineral powder, fly ash and water.

[0022] As a preferred selection embodiment, preferably, the preparation method of the pervious concrete in the scheme comprises:

[0023] S01, the stabilized steel slag is added into part of the water, then the mineral powder, the fly ash and the P·O4 2.5 cement are added and stirred, and then the remaining water is added and stirred;

[0024] S02, the material prepared in S01 is added into a mold, then a vibrating rod is used for vibrating, and then the material is placed on a vibrating table for vibrating;

[0025] S03, the material prepared in S02 is placed in a carbonization curing box for curing, 99% pure CO2 is introduced, a temperature of 20±3 DEG C and a relative humidity of 90% are maintained, and a plastic film with holes is used for covering, so as to avoid water loss and ensure the introduction of CO2, and after 28 days of curing, the preparation of the pervious concrete is completed.

[0026] As a preferred selection embodiment, preferably, the mass ratio of the mineral powder, the fly ash and the P·O4 2.5 cement in the scheme is 1.8:1.2:7, the water-cement ratio is 0.29, and the aggregate-cement ratio is 3.8.

[0027] Since the problem of the stability of the steel slag can be solved only by fundamentally reducing the content of f-CaO and f-MgO in the steel slag, the scheme of the present application proposes a process for preparing stabilized concrete coarse aggregate by boiling and carbonizing the steel slag, so that the steel slag can replace limestone as the coarse aggregate of the concrete, and the pervious concrete for roads is prepared by using the steel slag.

[0028] By using the technical scheme, the present application has the following beneficial effects compared with the prior art:

[0029] (1) The scheme of the present application ingeniously proposes a steel slag stabilization treatment method, the stabilized steel slag is used as the coarse aggregate for preparing the pervious concrete, and the comprehensive performance of the concrete can be improved, while in the traditional scheme, the steel slag which is not subjected to the stabilization treatment is used as the main admixture in the concrete product, and a large amount of energy is consumed due to the poor grindability of the steel slag, thereby further affecting the comprehensive performance of the concrete, and the stabilized steel slag is used as the aggregate in the scheme, so that the grinding is not needed, and the energy consumption is reduced.

[0030] (2) The scheme of the present application subjects the steel slag to boiling and carbonization treatment, and the concrete is subjected to film carbonization curing, so that the f-CaO and f-MgO are eliminated, the hydration is promoted, and the strength is increased.

[0031] (3) The scheme of the present application can realize resource utilization of steel slag, slag and fly ash, and can realize environmental protection and resource saving. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 is a schematic diagram of color change of the surface of the prepared stabilized steel slag after spraying phenolphthalein reagent on the stabilized steel slag prepared by the steel slag of the present application scheme embodiment 1 after different treatment parameters for stabilization treatment;

[0034] Figure 2 is a SEM image of the stabilized steel slag prepared by the present application scheme embodiment 1 as coarse aggregate to prepare pervious concrete and standard curing for 28 days;

[0035] Figure 3 is a SEM image of the stabilized steel slag prepared by the present application scheme embodiment 1 as coarse aggregate to prepare pervious concrete and carbonization curing for 28 days. DETAILED DESCRIPTION

[0036] The present application will be further described in detail below in combination with the drawings and embodiments. It is particularly pointed out that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only some embodiments of the present application, not all embodiments, and all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0037] Embodiment 1

[0038] The present embodiment is a steel slag stabilization treatment method, which comprises:

[0039] (1) The steel slag is crushed and then dried in a vacuum drying oven, the drying temperature is 100-110℃, and the drying time is 1-1.5h;

[0040] (2) The dried steel slag is screened to obtain steel slag within a preset particle size range, and the particle size of the obtained steel slag is in the range of 2.36-4.75mm, 4.75-9.5mm, 9.5-13.2mm, 13.2-16mm, 16-19mm;

[0041] (3) the screened steel slag is placed in a constant temperature water bath at 80-100°C for water bath heating treatment for 4-8h, then taken out and placed in a vacuum drying oven for drying at a temperature of 110-120°C, and the drying time is 1-3h;

[0042] (4) the steel slag treated in step (3) is placed in a carbonization reaction kettle, vacuumized to -0.1MPa, then pure CO2 with a purity of 99% is introduced, the carbonization pressure in the reaction kettle is adjusted to 0-0.2MPa, and carbonization treatment is carried out at a carbonization temperature of 40-80°C for 1.5-9.5h to obtain the stabilized steel slag after stabilization treatment.

[0043] In order to facilitate intuitive comparison of the stabilization effects of the steel slag obtained by water bath and heat treatment under different parameters, in step (1) of the embodiment, the broken steel slag is classified according to the particle size range as 2.36-4.75mm, 4.75-9.5mm, 9.5-13.2mm, 13.2-16mm, and 16-19mm.

[0044] Among them, the steel slag with a particle size of 2.36-4.75mm and 4.75-9.5mm is dried at 110°C for 1h;

[0045] The steel slag with a particle size range of 9.5-13.2mm, 13.2-16mm, and 16-19mm is dried at 110°C for 1.5h.

[0046] In addition, in step (3) of the scheme, the water bath heating temperature is adjusted to 80°C, and then the heating time of 4, 6, and 8h is used for treatment and grouping.

[0047] In addition, in step (3) of the scheme, when the particle size range of the steel slag is 2.36-4.75mm, it is dried at 110°C for 1h;

[0048] When the particle size range of the steel slag is 4.75-9.5mm, it is dried at 110°C for 1.5h;

[0049] When the particle size range of the steel slag is 9.5-13.2mm, it is dried at 110°C for 2h;

[0050] When the particle size range of the steel slag is 13.2-16mm, it is dried at 115°C for 2.5h;

[0051] When the particle size range of the steel slag is 16-19mm, it is dried at 120°C for 3h.

[0052] After the above treatment, the obtained stabilized steel slag is sprayed with phenolphthalein reagent, and then the surface color change of the stabilized steel slag is observed, and the obtained results are as follows Figure 1As shown, it can be clearly seen that water bath heating can eliminate part of the f-CaO.

[0053] In order to facilitate the comparison of the changes of f-CaO and f-MgO in the steel slag treated under different treatment parameters, the untreated steel slag is taken as a blank sample (referred to as the original steel slag sample) in this embodiment, and then two other test groups are taken, namely steel slag sample 2 and steel slag sample 3.

[0054] Among them, the particle size and treatment parameters of the steel slag sample 2 and the steel slag sample 3 are as follows:

[0055] The steel slag sample 2: particle size 13.2mm-16mm (step (1) 110℃ drying for 1.5h, step (3) 95℃ water bath heating for 7h, then 115℃ drying for 2.5h, step (4) carbonization reaction kettle first vacuum to-0.1MPa, then 99% CO2 is introduced, and then the carbonization pressure in the reaction kettle is adjusted to 0-0.2MPa, the carbonization temperature is 70℃, and the time is 8 hours)

[0056] The steel slag sample 3: particle size 9.5mm-13.2mm (step (1) 110℃ drying for 1.5h, step (3) 90℃ water bath heating for 6h, then 110℃ drying for 2h, step (4) carbonization reaction kettle first vacuum to-0.1MPa, then 99% CO2 is introduced, and then the carbonization pressure in the reaction kettle is adjusted to 0-0.2MPa, the carbonization temperature is 60℃, and the time is 5 hours)

[0057] The contents of f-CaO and f-MgO in the original steel slag sample, the steel slag sample 2 and the steel slag sample 3 are detected, and the results are shown in Table 1:

[0058] Table 1

[0059] Detection sample Detection item Detection result (%) Steel slag as is f-CaO, f-MgO 3.29、2.58 Steel slag sample 2 f-CaO, f-MgO 1.03、0.86 Steel slag sample 3 f-CaO, f-MgO 0.57、0.23

[0060] In order to facilitate the verification of the effect of the stabilized steel slag as coarse aggregate added into the concrete, the stabilized steel slag is used to prepare the water permeable concrete in this scheme, and the raw material preparation is as follows:

[0061] Stabilized steel slag, P·O42.5 cement, mineral powder, fly ash, water.

[0062] The preparation process is as follows:

[0063] (1) According to the preset ratio of the mass ratio of mineral powder, fly ash and cement 1.8:1.2:7, the water-cement ratio 0.29, and the aggregate ratio 3.8, the mixed materials are mixed in the following order:

[0064] Carbonized steel slag→water (stirring)→mineral powder, fly ash, cement (stirring)→water (stirring)

[0065] (2) The stirred concrete is poured into a 150x150x150mm mold and vibrated with a vibrating rod, and placed on a vibrating table for vibration;

[0066] (3) The concrete is placed in a carbonation curing box, 99% pure CO2 is introduced, the temperature is 20±3℃, the relative humidity is 90%, and the concrete is covered with a plastic film with holes to prevent water loss and ensure the introduction of CO2, and cured for 28 days.

[0067] The compressive strength is detected according to the national standard GB50081-2002 "Standard for Testing Methods of Mechanical Properties of Ordinary Concrete", and the permeable coefficient is detected according to the provisions of CJJ / T135-2009 "Technical Specification for Permeable Cement Concrete Pavement".

[0068] For easy comparison, the standard curing (i.e., step (3) curing without carbon dioxide) and the permeable concrete obtained by the above carbonation curing are compared microscopically, wherein the standard curing conditions are temperature 20±3℃, relative humidity 90%; the carbonation curing conditions are that the concrete is placed in a carbonation curing box, 99% pure CO2 is introduced, the temperature is 20±3℃, the relative humidity is 90%, and the concrete is covered with a plastic film with holes; Figure 2 、 Figure 3 The SEM images of the concrete cured for 28 days under standard conditions and carbonation curing for 28 days, respectively, wherein the steel slag aggregate used is carbonated and has a particle size of 9.5-13.2mm, it can be clearly seen that more hydration products are generated under carbonation curing conditions.

[0069] Example 2

[0070] The steel slag stabilization method of the present embodiment comprises:

[0071] (1) Steel slag raw material pretreatment: The steel slag is crushed and then placed in a vacuum drying oven for drying, the drying temperature is 100-110℃, the time is 1-1.5 hours, and the dried steel slag is reserved;

[0072] (2) Steel slag particle classification: The dried steel slag is placed in a vibrating screen machine for screening, and the steel slag with a particle size of 9.5-13.2mm is taken out for reservation;

[0073] (3) The constant temperature water bath pot is adjusted to 90℃, after the water bath pot rises to the specified temperature, the steel slag is placed in and heated for 6 hours, then taken out and placed in a vacuum drying oven at 110℃ for drying for 2 hours, and the dried steel slag is taken out for reservation;

[0074] (4) The dried steel slag is placed in a carbonation reactor, the carbonation reactor is vacuumed to-0.1MPa, then 99% pure CO2 is introduced, the carbonation pressure in the reactor is adjusted to 0-0.2MPa, the carbonation temperature is 60℃, and the carbonation time is 5 hours, and the stabilized steel slag is obtained after taking out.

[0075] The stabilized steel slag of the embodiment is used to prepare water permeable concrete, and the method comprises the following steps:

[0076] (1) raw material preparation: stabilized steel slag, P·O42.5 cement, mineral powder, fly ash, water;

[0077] (2) the mass ratio of the mineral powder, the fly ash and the cement is 1.8:1.2:7, the water-cement ratio is 0.29, and the aggregate ratio is 3.8, and the feeding sequence is as follows:

[0078] carbonized steel slag→water (stirring)→mineral powder, fly ash, cement (stirring)→water (stirring)

[0079] (3) the stirred concrete is poured into a 150*150*150mm mold and vibrated with a vibrating rod, and then placed on a vibrating table for vibration;

[0080] (4) the concrete is placed in a carbonization curing box, 99% pure CO2 is introduced, the temperature is 20±3℃, the relative humidity is 90%, and the plastic film with holes is covered to prevent water loss and ensure the introduction of CO2. Curing for 28 days.

[0081] The compressive strength is detected according to the national standard GB50081-2002 “Standard for Testing Methods of Mechanical Properties of Ordinary Concrete”, and the water permeability coefficient test is detected according to the provisions of CJJ / T135-2009 “Technical Specification for Permeable Cement Concrete Pavement”.

[0082] The aggregate particle size is selected to be 9.5-13.2mm, the compressive strength is 16.76MPa, the water permeability coefficient is 4.62mm / s, and the requirements of CJJ / T135-2009 “Technical Specification for Permeable Cement Concrete Pavement” are met.

[0083] Embodiment 3

[0084] The steel slag stabilization treatment method of the embodiment comprises the following steps:

[0085] (1) steel slag raw material pretreatment: the steel slag is crushed and then placed in a vacuum drying oven for drying, the drying temperature is 100-110℃, the time is 1-1.5 hours, and the dried steel slag is reserved;

[0086] (2) steel slag particle classification: the dried steel slag is placed in a vibrating screen machine for screening, and the steel slag with a particle size of 13.2-16mm is taken out for reservation;

[0087] (3) the constant-temperature water bath pot is adjusted to 95℃, after the water bath pot is raised to the specified temperature, the steel slag is placed in the water bath pot for heating for 7 hours, then taken out and placed in a vacuum drying oven for drying at 115℃ for 2.5 hours, and the dried steel slag is taken out for reservation;

[0088] (4) The dried steel slag is placed into a carbonization reactor, the carbonization reactor is vacuumized to -0.1 MPa, then 99% pure CO2 is introduced, the carbonization pressure in the reactor is adjusted to 0-0.2 MPa, the carbonization temperature is 70°C, and the carbonization time is 8 hours. The stabilized steel slag is obtained after being taken out.

[0089] The stabilized steel slag of the embodiment is used to prepare water permeable concrete, and the method comprises the following steps:

[0090] (1) Raw material preparation: stabilized steel slag, P·O42.5 cement, mineral powder, fly ash, and water;

[0091] (2) The mass ratio of the mineral powder, the fly ash, and the cement is 1.8:1.2:7, the water-cement ratio is 0.29, the aggregate ratio is 3.8, and the feeding sequence is as follows:

[0092] Carbonized steel slag→water (stirring)→mineral powder, fly ash, and cement (stirring)→water (stirring)

[0093] (3) The stirred concrete is poured into a 150×150×150 mm mold, and is vibrated and compacted on a vibrating table.

[0094] (4) The concrete is cured in a carbonization curing box, 99% pure CO2 is introduced, the temperature is 20±3°C, the relative humidity is 90%, and a plastic film with holes is used for covering, so as to avoid water loss and ensure the introduction of CO2, and the curing time is 28 days.

[0095] The compressive strength is detected according to the national standard GB50081-2002 “Standard for Test Methods of Mechanical Properties of Ordinary Concrete”, and the water permeability coefficient is detected according to the provisions of CJJ / T135-2009 “Technical Specification for Permeable Cement Concrete Pavement”.

[0096] The aggregate particle size is selected to be 13.2-16 mm, the compressive strength is 18.81 MPa, the water permeability coefficient is 2.62 mm / s, and the requirements of CJJ / T135-2009 “Technical Specification for Permeable Cement Concrete Pavement” are met.

[0097] The above only describes some embodiments of the present application, and does not limit the protection scope of the present application, and any equivalent device or equivalent process conversion according to the content of the specification and the drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for stabilizing steel slag, characterized by, It comprises: (1) The steel slag is crushed and then placed in a vacuum drying oven for drying, the drying temperature is 100-110 DEG C, the drying time is 1-1.5 h; when the particle size range of the crushed steel slag is 2.36-4.75 mm or 4.75-9.5 mm, 100 DEG C is used for drying for 1 h; when the particle size range of the steel slag is 9.5-13.2 mm or 13.2-16 mm or 16-19 mm, 110 DEG C is used for drying for 1.5 h; (2) The dried steel slag is screened to obtain steel slag with a predetermined particle size range; (3) The screened steel slag is placed in a constant temperature water bath pot at 80-100 DEG C for water bath heating treatment for 4-8 h, then taken out and placed in a vacuum drying oven for drying at a temperature of 110-120 DEG C, the drying time is 1-3 h; when the particle size range of the steel slag is 2.36-4.75 mm, 110 DEG C is used for drying for 1 h; When the particle size range of the steel slag is 4.75-9.5 mm, 110 DEG C is used for drying for 1.5 h; When the particle size range of the steel slag is 9.5-13.2 mm, 110 DEG C is used for drying for 2 h; When the particle size range of the steel slag is 13.2-16 mm, 115 DEG C is used for drying for 2.5 h; When the particle size range of the steel slag is 16-19 mm, 120 DEG C is used for drying for 3 h; (4) The steel slag treated in step (3) is placed in a carbonization reaction kettle, vacuumed to-0.1 MPa, then pure CO2 with a purity of 99% is introduced, the carbonization pressure in the reaction kettle is adjusted to 0-0.2 MPa, and carbonization treatment is carried out at a carbonization temperature of 40-80 DEG C for 1.5-9.5 h to obtain stabilized steel slag after stabilization treatment.

2. The steel slag stabilization treatment method according to claim 1, characterized by, In step (2), the particle size of the obtained steel slag ranges from 2.36 to 4.75 mm, 4.75 to 9.5 mm, 9.5 to 13.2 mm, 13.2 to 16 mm, or 16 to 19 mm.

3. The steel slag stabilization treatment method according to claim 1, characterized by, In step (3), the water bath heating temperature is 80 DEG C, and the heating time is 4, 6 or 8 h.

4. Use of the stabilized steel slag produced by the method for stabilizing steel slag according to any one of claims 1 to 3 in the production of pervious concrete, characterized in that, The prepared stabilized steel slag is added to the concrete formula as coarse aggregate to prepare pervious concrete.

5. The use according to claim 4, wherein the compound is ###0002### The concrete formula comprises stabilized steel slag, P·O42.5 cement, mineral powder, fly ash and water.

6. The use according to claim 5, wherein the compound is ###00003### or a pharmaceutically acceptable salt thereof. The preparation method of the pervious concrete comprises: S01, adding the stabilized steel slag to part of the water, then adding the mineral powder, fly ash and P·O42.5 cement and continuing to stir, then adding the remaining water and continuing to stir; S02, adding the material prepared in S01 to a mold, then vibrating with a vibrating rod, and then placing on a vibrating table for vibrating; S03, placing the material prepared in S02 in a carbonization curing box for curing, then introducing CO2 with a purity of 99%, maintaining a temperature of 20±3 DEG C and a relative humidity of 90%, and covering with a plastic film with holes to avoid water loss while ensuring the introduction of CO2, and after 28 days of curing, the preparation of the pervious concrete is completed.

7. Use according to claim 6, wherein The mass ratio of the mineral powder, fly ash and P·O42.5 cement is 1.8:1.2:7, the water-cement ratio is 0.29, and the aggregate ratio is 3.8.

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