Method for pumping hydrated iron and steel slag

Abstract

To demonstrate improved flowability and viscosity and achieve longer-distance pressure feeding.SOLUTION: A pressure feeding method for a steel slag hydration solidified body according to the present invention includes, after setting the volume of water to the range of 0.13 to 0.30 m3 per 1 m3 of the hydration solidified body, mixing powder with the volume ratio of water to powder in the range of 0.57 or more and less than 1.44 with the balance of steel slag, and feeding the obtained mixture by pressure.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for pumping iron and steel slag hydrated bodies. [Background technology]

[0002] In recent years, various technologies have been proposed for hydrated hardened bodies (also called "steel slag hydrated bodies") that can be used as a substitute for concrete and are made primarily from powders such as ground granulated blast furnace slag and steelmaking slag (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-210848 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the present inventor attempted to cast the hydrated hardened body as disclosed in the above-mentioned Patent Document 1 into a remote area indoors, it became apparent that the mixture had poor pumpability and there was concern that the pumping pipes might become clogged or burst.

[0005] There are three possible reasons why the pumpability of steel slag hydrated bodies is low. First, steel slag used as the aggregate of the mixture is more porous than the aggregate used in normal concrete, so it is more likely to absorb moisture and its fluidity is more likely to decrease. Second, the strength development of ground granulated blast furnace slag, which is often used as the main powder, is about half that of cement, so the amount of powder required to develop the desired strength increases, resulting in higher viscosity and higher pumping load. Third, steel slag hydrated bodies generally harden faster than concrete, so their fluidity decreases rapidly, resulting in changes in fluidity between the pumping source and pumping destination.

[0006] Since the steel slag hydrated body is a composite material of water, powder, and steel slag, the steel slag hydrated body mixture must have appropriate fluidity and viscosity depending on the application conditions. For example, if the fluidity of the mixture is too low, the mixture cannot be pumped, and if the fluidity is too high, the materials will separate. Also, if the viscosity of the mixture is too low, the materials will separate, and if the viscosity is too high, the pump capacity for pumping will be insufficient, making pumping difficult.

[0007] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for pumping steel slag hydrated bodies that exhibits better fluidity and viscosity and can be pumped over longer distances. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors conducted extensive research and aimed to determine the blending amount of material that can achieve both fluidity and viscosity, which are in a trade-off relationship, and succeeded in determining the blending amount that can be pumped over long distances of 85 m or more. The gist of the present invention, which was completed based on these findings, is as follows.

[0009] (1) A method for pumping iron and steel slag hydrated bodies, comprising the steps of: 3 The volume of water is 0.13 to 0.30 m 3 The water to powder volume ratio is within the range of 1.16 The powder having a molecular weight of 1.51 or more and less than 1.44 is mixed with the remainder of the steelmaking slag, and the resulting mixture is Pumping speed: 5.0~50.0m 3 Within the range of / h Pressure feed The powder used is at least ground granulated blast furnace slag and ordinary Portland cement. A method for pumping hydrated steel slag solidified bodies. ( 2 The volume of the water is 0.16 to 0.22 m 3 Within the range of ( 1 ) A method for pumping the iron and steel slag hydrated solidified body described in the above. ( 3 ) The powder As , Furthermore, Granulated blast furnace slag, High early strength Portland cement, fly ash Cement, fly ash, slaked lime, or at least one of fine aggregate and coarse aggregate is used , (1) Or (2) A method for pumping the iron and steel slag hydrated solidified body described in claim 1. ( 4 ) The mixture further contains an admixture conforming to JIS A 6204 in place of a part of the volume of the water, (1) to ( 3 ) A method for pumping iron and steel slag hydrated bodies according to any one of the above. ( 5 ) the steelmaking slag is at least one selected from the group consisting of converter slag, pretreatment slag, decarburization slag, dephosphorization slag, desulfurization slag, desiliconization slag, electric furnace reduction slag, electric furnace oxidation slag, secondary refining slag, and ingot casting slag; (1) to ( 4 ) A method for pumping iron and steel slag hydrated bodies according to any one of the above. ( 6 ) The mixture has a slump flow value in the range of 31.5 cm or more and less than 88.5 cm, and a V-funnel test value in the range of 4 to 20 seconds, (1) to ( 5 ) A method for pumping iron and steel slag hydrated bodies according to any one of the above. ( 7 ) The mixture has a slump flow value in the range of 50.0 cm or more and 70.0 cm or less; ( 6 ) A method for pumping the iron and steel slag hydrated solidified body described in the above. Effect of the Invention

[0010] As described above, according to the present invention, a material exhibits superior fluidity and viscosity, and can be pumped over longer distances. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an explanatory diagram for explaining a method for measuring a slump flow value. [Diagram 2] FIG. 2 is an explanatory diagram for explaining a method for measuring V-funnel test values. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0013] (Method of pumping hydrated iron and steel slag) A method for pumping an iron and steel slag hydrated material according to an embodiment of the present invention will be described in detail below with reference to Figures 1 and 2. Figure 1 is an explanatory diagram for explaining a method for measuring a slump flow value, and Figure 2 is an explanatory diagram for explaining a method for measuring a V-funnel test value.

[0014] In the method for pumping the steel slag hydrated solidified matter according to the present embodiment, 3 The volume of water is 0.13 to 0.30 m 3 After adjusting the water-powder volume ratio to within the range of 0.57 or more and less than 1.44, the powder is mixed with the remainder of the steelmaking slag, and the resulting mixture is pumped.

[0015] [Wed:0.13~0.30m 3 ] In the method for pumping the steel slag hydrated solidified matter according to the present embodiment, 3 The amount of water per unit is 0.13 to 0.30 m 3 This allows the mixture to be pumped over long distances of 85m or more while achieving both superior fluidity and viscosity. 3 The amount of water per unit is 0.13 m 3 If the ratio is less than 1 / 3, the water content in the resulting mixture will be too low, resulting in poor pumpability of the mixture. 3 The amount of water per unit is preferably 0.15 m 3 More preferably, it is 0.16m or more. 3 On the other hand, 1m of hydrated solidified material 3 The amount of water used per unit is 0.30 m 3If the temperature exceeds this range, the proportion of water in the resulting mixture will be too high, making it impossible to maintain the strength of the steel slag hydrated material obtained by solidifying and curing the mixture within the desired range. 3 The amount of water per unit is preferably 0.23 m 3 or less, more preferably 0.22m 3 The following is the result.

[0016] The water used here is not particularly limited, but it is preferable to use tap water, seawater, or water conforming to JSCE-B 101 or JIS A 5308 Annex 9, for example.

[0017] [Volume where the powder:water / powder volume ratio is between 0.57 and 1.44] In the method for pumping the steel slag hydrated solidified body according to the present embodiment, the amount of powder mixed is set to a volume such that the water-powder volume ratio is in the range of 0.57 or more and less than 1.44 with respect to the volume of water set as above. This makes it possible to pump the resulting mixture over a long distance of 85 m or more while achieving both better fluidity and viscosity. Here, the water-powder volume ratio is a volume ratio expressed as (volume of water in the mixture / volume of powder in the mixture). When the water-powder volume ratio is less than 0.57, the amount of water mixed is too small, so the viscosity increases and the pumpability of the mixture decreases. The water-powder volume ratio is preferably 0.60 or more, more preferably 0.70 or more. On the other hand, when the water-powder volume ratio is 1.44 or more, the amount of water mixed is too large, so the viscosity decreases, and separation of the materials used in the mixture occurs. The water-powder volume ratio is preferably 1.30 or less, more preferably 1.16 or less.

[0018] In this embodiment, the powder used is preferably at least any one of ground granulated blast furnace slag, granulated blast furnace slag, cement, fly ash, slaked lime, fine aggregate, and coarse aggregate.

[0019] The finely ground blast furnace slag is obtained by separating and recovering components other than iron from iron ore melted in a blast furnace used to produce pig iron, together with the auxiliary raw materials limestone and ash from the coke, and is then finely ground. It is possible to use blast furnace slag that complies with JIS A 6206. More specifically, it is possible to use granulated slag that has been rapidly cooled by injecting pressurized water into the molten slag and then finely ground. The degree of fine grinding of granulated slag is generally 3000 to 8000 cm. 2 / g.

[0020] Granulated blast furnace slag is produced by quenching molten blast furnace slag produced in the pig iron making process with water and pulverizing it into fine particles, and has weak hydraulic properties and is effective in improving workability. As such granulated blast furnace slag, it is preferable to use slag used as a raw material in JIS A 6206 or JIS A 5011-1.

[0021] Cement is classified into Portland cement and blended cement. Of these, Portland cement is classified into ordinary Portland cement and high-early-strength Portland cement, and blended cement is mainly classified into blast-furnace cement and fly ash cement. Among these, blast-furnace cement is generally made by grinding granulated blast-furnace slag and mixing it with ordinary Portland cement, and is classified into three types, A to C, depending on the amount of blast-furnace slag (JIS R 5211). In this embodiment, any of these cements may be used.

[0022] Fly ash is a type of ash that is produced when coal is burned, and it is preferable to use fly ash that conforms to JIS A 6201.

[0023] Slaked lime is a substance that functions as an alkali stimulant in the iron and steel slag hydrated solidified body, and may be added to further promote hardening of the mixture. There is no particular limitation on the slaked lime used, and various known slaked limes can be used.

[0024] As the fine aggregate and coarse aggregate (more specifically, fine aggregate and coarse aggregate excluding granulated blast furnace slag), various natural aggregates can be used, and it is preferable to use those specified in the "Standard Specifications for Concrete [Construction Section]" of the Japan Society of Civil Engineers. Examples of such fine aggregate and coarse aggregate include crushed sand, crushed stone, and blast furnace slag coarse aggregate.

[0025] [Remainder: Steelmaking slag] In the method for pumping the steel slag hydrated solidified matter according to the present embodiment, 3 The remainder of the water and powder is steel slag. This allows the resulting mixture to be pumped over long distances of 85m or more while achieving both superior fluidity and viscosity.

[0026] Steelmaking slag is mainly composed of limestone and is generated in the steelmaking process in which unnecessary components are removed from pig iron produced in a blast furnace or molten steel produced from scrap to produce tough and workable steel. In this embodiment, the steelmaking slag may be one or a mixture of two or more of converter slag, pretreatment slag, decarburization slag, dephosphorization slag, desulfurization slag, desiliconization slag, electric furnace reduction slag, electric furnace oxidization slag, secondary refining slag, ingot casting slag, etc.

[0027] The chemical components of the steelmaking slag are not particularly limited. However, if the basicity defined by CaO content / SiO2 content is too high, free CaO may remain inside the steelmaking slag, which may cause a large variation in volume stability. Therefore, the basicity of the steelmaking slag is preferably about 2.0 to 5.0.

[0028] Steelmaking slag may expand due to the hydration reaction of the free lime (f-CaO) contained therein, and depending on the use of the resulting solidified body, it may be undesirable for cracks to occur on the surface. Therefore, when it is required to prevent cracks from occurring in the target solidified body, it is preferable to use steelmaking slag that has been subjected to an aging treatment such as natural aging or steam aging. More specifically, it is preferable to use steelmaking slag that has been aged so that the powdering rate determined by the following method is 2.5% or less.

[0029] Here, the above powdering rate is a value based on mass. That is, a certain amount of aged steelmaking slag (mass S0) is classified using a first sieve (for example, a 4.75 mm sieve as specified in JIS Z8801-1), and the slag that falls under this sieve is further classified using a second sieve that is one step smaller than the first sieve (in the above example, a 2 mm sieve, which is one step smaller than the first sieve as specified in JIS Z8801-1), and relatively large slag particles that have not been disintegrated are removed, and the fine grain fraction of the aged steelmaking slag is obtained as the sieve that falls under the sieve (mass S1). Then, {(slag mass under the second sieve = S1} / (slag mass after aging before classification = S0)) × 100 (%)} is defined as the powdering rate, and if a steelmaking slag with a powdering rate of 2.5% or less is used, it is possible to suppress cracks that occur in the obtained solidified body.

[0030] In addition, it is preferable to use steel slag having a particle size of 5 mm or less after crushing and sieving it. Steel slag having such a particle size can obtain the expansion suppression effect, even if it has not been aged.

[0031] [Admixture] In the method for pumping the steel slag hydrated solidified matter according to this embodiment, the mixture containing the water, powder, and steel slag may further contain an admixture conforming to JIS A 6204 in place of a portion of the volume of water. By including an admixture in the mixture, it becomes possible to more easily adjust the water / powder volume ratio.

[0032] By mixing the above-mentioned materials, a mixture to be pumped can be obtained. Here, the method for mixing the above-mentioned materials is not particularly limited, and various known methods can be appropriately used.

[0033] [Slump flow value of mixture: 31.5 cm or more and less than 88.5 cm] The mixture obtained as described above preferably has a slump flow value of 31.5 cm or more. When the slump flow value is 31.5 cm or more, the fluidity of the mixture becomes more favorable, and the pumpability of the mixture can be further improved. The slump flow value is more preferably 50.0 cm or more. On the other hand, the slump flow value is preferably less than 88.5 cm. When the slump flow value is less than 88.5 cm, the viscosity of the mixture becomes more favorable, and the pumpability of the mixture can be further improved. The slump flow value is more preferably 70.0 cm or less.

[0034] Here, the slump flow value of the mixture can be measured by using an instrument as shown in FIG. 1. A cylindrical container made of iron, for example, having the dimensions as shown in the left diagram of FIG. 1 is prepared, and the cylindrical container is placed on the surface of an iron plate or the like. Then, the mixture to be measured is charged into the gap inside the cylindrical container, and the gap is filled with the mixture while expelling the air by tapping the side of the cylindrical container lightly, and the surface is scraped. After that, the cylindrical container is pulled up, and the diameter (length d in FIG. 1) of the mixture spread on the surface of the iron plate or the like is measured. At this time, the maximum and minimum diameters of the mixture spread on the surface of the iron plate or the like are measured, and the average of the measured values ​​obtained is taken as the slump flow value of the mixture of interest.

[0035] [V-funnel test value of mixture: 4 to 20 seconds] The mixture obtained as described above preferably has a V-funnel test value of 4 seconds or more. When the V-funnel test value is 4 seconds or more, the viscosity of the mixture becomes more favorable, and the pumpability of the mixture can be further improved. On the other hand, the V-funnel test value is preferably 20 seconds or less. When the V-funnel test value is 20 seconds or less, the fluidity of the mixture becomes more favorable, and the pumpability of the mixture can be further improved. The V-funnel test value is more preferably 11 seconds or less.

[0036] Here, the V-funnel test value of the mixture can be measured by using an instrument as shown in FIG. 2. Prepare a V-funnel made of iron, for example, with the dimensions as shown in the left diagram of FIG. 2, and make sure that the mixture does not flow out from the bottom end of the V-funnel. Then, fill the gap with the mixture while expelling the air by tapping the side of the V-funnel lightly, and scrape the surface. After that, open the bottom end of the V-funnel and measure the elapsed time until the mixture inside completely flows down. The judgment of the total amount flowing down is the moment when the mixture is observed flowing down from above the V-funnel and the space below is seen through the V-funnel. This measurement is carried out multiple times, and the average of the elapsed times obtained is taken as the V-funnel test value.

[0037] [Mixture pumping speed: 5.0~50.0m 3 / h] The mixture of the steel slag hydrated solidified matter according to this embodiment satisfies the above conditions and therefore exhibits excellent pumpability, making it possible to maintain the quality of the mixture in a good condition while allowing the pumping speed of the mixture to have a certain range. However, if the pumping speed is 5.0 m 3 If the pumping speed of the mixture is less than 5.0 m / h, the quality difference between the pumping source and the pumping destination may be significant even if the mixture according to the present embodiment is used. 3 / h or more is preferable, and 7.8m 3 On the other hand, the pumping speed is preferably 50.0 m / h or more. 3If the pumping speed exceeds 50.0 m / h, the steel slag aggregate is porous, and the apparent water volume decreases when pressure is applied, which increases the possibility of the fluidity worsening and the pipes becoming clogged. 3 / h or less, and 32.0m 3 In this way, in the method for pumping the iron and steel slag hydrated material according to the present embodiment, the pumping speed of the mixture is set to 5.0 to 50.0 m / h or less. 3 It is possible to set the desired speed within the range of 1 / h.

[0038] The method for pumping iron and steel slag hydrated bodies according to this embodiment has been described in detail above. EXAMPLES

[0039] The method for pumping iron and steel slag hydrated solidified materials according to the present invention will be specifically described below with reference to examples and comparative examples. Note that the examples shown below are merely examples of the method for pumping iron and steel slag hydrated solidified materials according to the present invention, and the method for pumping iron and steel slag hydrated solidified materials according to the present invention is not limited to the following examples.

[0040] (Test Example) In the following examples and comparative examples, steelmaking slag A (converter furnace slag) having the components shown in Table 1 was used, and as the powder, blast-furnace cement type B specified in JIS R 5211 was used. In addition, as the admixture, TS-1000 manufactured by Flolic Co., Ltd., which is an admixture conforming to JIS A 6204, was used.

[0041] [Table 1]

[0042] The volume of water (tap water) shown in Table 2 below (1 m of hydrated solid) 3The powder, steel slag, and admixtures, if necessary, were mixed in the volumes shown in Table 2 below for the total volume of the concrete (volume per unit area) to obtain mixtures. A twin-axis forced mixer was used to mix these components. The slump flow value and V-funnel test value of each of the obtained mixtures were measured according to the method previously explained.

[0043] The resulting mixture was pumped using a Kyokuto concrete pump truck (model number PY90-17) at a speed of 8.0 m 3 / h, 17.0m 3 / h, 31.6m 3 It was verified whether each mixture could be pumped 85 m at three different pumping speeds of 100 / h.

[0044] [Table 2]

[0045] As a result, in the examples of No. 1 and No. 2, the mixture could be pumped over a long distance of 85 m without separation under the above three pumping speeds. On the other hand, in the example of No. 3, the water-powder volume ratio was outside the range of the present invention, so the viscosity of the mixture was low, and clogging occurred in the piping due to material separation of the mixture, and it was not possible to pump the long distance of 85 m.

[0046] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

Claims

1. A method for pumping iron and steel slag hydrated bodies, comprising the steps of: 1 m of the hydrated solid ３ The volume of water is 0.13 to 0.30 m ３ The powder having a water-powder volume ratio in the range of 1.16 to less than 1.44 is mixed with the remaining steelmaking slag, The mixture obtained is pumped at a pumping rate in the range of 5.0 to 50.0 m 3 / h, A method for pumping a steel slag hydrated body, wherein at least ground granulated blast furnace slag and ordinary Portland cement are used as the powder.

2. The volume of the water is 0.16 to 0.22 m ３ 2. The method for pumping iron and steel slag hydrated bodies according to claim 1, wherein the pressure is within the range of 100 MPa.

3. The method for pumping steel slag hydrated solidified bodies according to claim 1 or 2, wherein the powder further comprises at least one of granulated blast furnace slag, high-early-strength Portland cement, fly ash cement, fly ash, hydrated lime, fine aggregate, and coarse aggregate.

4. The method for pumping steel slag hydrated bodies according to any one of claims 1 to 3, wherein the mixture further contains an admixture conforming to JIS A 6204 in place of a part of the volume of the water.

5. The method for pumping a steel slag hydrated body according to any one of claims 1 to 4, wherein the steelmaking slag is at least one selected from the group consisting of converter slag, pretreatment slag, decarburization slag, dephosphorization slag, desulfurization slag, desiliconization slag, electric furnace reduction slag, electric furnace oxidization slag, secondary refining slag, and ingot casting slag.

6. The method for pumping iron and steel slag hydrated solidified bodies according to any one of claims 1 to 5, wherein the mixture has a slump flow value in the range of 31.5 cm or more and less than 88.5 cm, and a V-funnel test value in the range of 4 to 20 seconds.

7. 7. The method for pumping iron and steel slag hydrated bodies according to claim 6, wherein the mixture has a slump flow value in the range of 50.0 cm or more and 70.0 cm or less.

Images