NL2027168A

NL2027168A - Steel slag powder-ferromanganese ore slag powder composite admixture and preparation process thereof

Info

Publication number: NL2027168A
Application number: NL2027168A
Authority: NL
Inventors: Chen Meizhu; Li Hao; Ren Yanfei; Wu Shaopeng; Xie Jun
Original assignee: Univ Wuhan Tech
Priority date: 2020-03-06
Filing date: 2020-12-18
Publication date: 2021-10-19
Also published as: CN111302691A; NL2027168B1

Abstract

The present disclosure discloses a steel slag powder-ferromanganese ore slag powder composite admixture and a preparation process thereof. The composite admixture includes the following components in percentage by weight: 5-30% of ferromanganese ore slag powder and 70%-95% of steel slag powder. The preparation method of the composite admixture includes the steps: respectively drying, crushing, grinding, and grading or sieving ferromanganese ore slag and steel slag to obtain ferromanganese ore slag powder and steel slag powder; and then uniformly mixing the ferromanganese ore slag powder and the steel slag powder according to the weight percentages to obtain the steel slag powder-ferromanganese ore slag powder composite admixture, wherein properties of the steel slag powder meet the Grade II technical requirements in the standard GB/T2049l-2017 "Steel Slag Powder Used for Cement and Concrete". According to the present disclosure, the ferromanganese ore slag powder and the steel slag powder are mutually excited to produce a micro-aggregate effect, so that the ﬂuidity and compressive and ﬂexural activities of the admixture in cement mortar are enhanced, the concrete slump with time is increased, and the compressive strength and ﬂexural strength of the concrete are enhanced.

Description

STEEL SLAG POWDER-FERROMANGANESE ORE SLAG POWDER

COMPOSITE ADMIXTURE AND PREPARATION PROCESS THEREOF Field

[0001] The present disclosure belongs to the technical field of building materials, and particularly relates to a steel slag powder-ferromanganese ore slag powder composite admixture and a preparation process thereof. Background

[0002] Protecting the environment, lowering the consumption of natural resources and enhancing the properties of cement concrete are the two most important issues faced by the field of cement and concrete at present. On one hand, the application of concrete admixtures can effectively control the total output of Portland cement, so that the existing industrial waste residues can be recycled and reutilized, thereby lowering the burden of the building material industry itself and other industries on the resources and the environment, on the other hand, the concrete admixtures can significantly improve the mechanical properties, working properties, corrosion resistance, durability and the like of concrete, and are an indispensable structural component of current high-property concrete. Therefore, how to utilize industrial waste residues, natural minerals and low-grade mineral admixtures to prepare high-strength high-property concrete is one of the current research hotspots.

[0003] Steel slag is a solid waste discharged in the steelmaking process, and the discharge amount of steel slag is generally about 15-20% of steel output. In 2017, China's crude steel output reached 832 million tons, accounting for 49. 18% of the world's total output. The annual discharge amount of steel slag in China is about 133 million tons. A large amount of steel slag is left unused, which seriously pollutes the environment and occupies the land. Therefore, there is an urgent need to reduce the amount of steel slag, use the steel slag as secondary resources and efficiently utilize the steel slag. Research results in recent years indicate that the development of steel slag as a cement admixture or a concrete admixture is likely to become an important way for its efficient high-added-value utilization. Steel slag is rich in minerals such as C3S, CS and the like, is an industrial waste residue similar to inferior Portland cement clinker, and has the potential to be developed as a raw material for production of cement and concrete. The use of steel slag micropowder as a supplementary cementing material can improve the wear resistance, impact resistance and other properties of cement concrete. The steel slag used as a supplementary cementing material to reduce the use amount of cement clinker can not only reduce the pressure of the cement industry on resources, energy and environment, but also solve the environmental problems caused by waste in the iron and steel industry, which has an irreplaceable win-win effect for promoting the sustainable development of China's iron and steel industry and building material industry.

[0004] Ferromanganese ore slag has certain hydraulicity and pozzolanicity after being quenched by water, is a material with high potential activity, and has application development values. At present, the ferromanganese ore slag has not yet been fully developed and utilized in China. Except that 30% is used for cement admixtures and re-melting in a furnace for smelting, the rest 70% is used for landfill treatment, with an annual net discharge amount of 12 million tons. The specific surface area of manganese slag ground alone for the cement admixture is about 420m?/kg, and the manganese slag is added in a compound form. Relevant research only stays at the research stage of mortar. At present, there is no relevant research report on the preparation of concrete fine admixtures for concrete from ferromanganese ore slag powder.

Summary

[0005] Based on the above defects of the prior art, considering that steel slag powder has low early strength when used alone and ferromanganese ore slag powder has higher activity, if the steel slag powder and the ferromanganese ore slag powder are combined and mutually excited, it is expected to fill the voids of cement particles and produce a micro-aggregate effect, thereby preparing a composite admixture with high early strength, continuously increased later strength and a shrinkage compensating effect. The technical problem to be solved by the present disclosure is to provide a steel slag powder-ferromanganese ore slag powder composite admixture and a preparation process thereof. Concrete blended with the composite admixture has high compressive strength. The preparation process is simple in process and easy to operate, and can be used to prepare a composite admixture with high early strength, continuously increased later strength and a shrinkage compensating effect.

[0006] In order to solve the above technical problem, the present disclosure provides a steel slag powder-ferromanganese ore slag powder composite admixture, including the following components in percentage by weight: 5-30% of ferromanganese ore slag powder and 70%-95% of steel slag powder, wherein properties of the steel slag powder meet the Grade II technical requirements in the standard GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete".

[0007] As a preferred technical solution, the steel slag powder-ferromanganese ore slag powder composite admixture provided by the present disclosure further includes part or all of the following technical features:

[0008] As an improvement of the above technical solution, the steel slag powder has a median diameter Dao, of smaller than or equal to 15 um.

[0009] As an improvement of the above technical solution, the ferromanganese ore slag powder has a median diameter Do) of smaller than or equal to 10 um.

[0010] As an improvement of the above technical solution, the steel slag powder has a specific surface area of 400-500 m?/kg.

[0011] As an improvement of the above technical scheme, the ferromanganese ore slag powder has a specific surface area of 400-600 m?/kg.

[0012] A preparation process of the steel slag powder-ferromanganese ore slag powder composite admixture includes the following steps:

[0013] 1) respectively drying, crushing, grinding, and grading or sieving ferromanganese ore slag and steel slag to obtain ferromanganese ore slag powder and steel slag powder; and

[0014] 2) uniformly mixing the ferromanganese ore slag powder and the steel slag powder according to weight percentages of 5%-30% and 70%-95% to obtain the steel slag powder- ferromanganese ore slag powder composite admixture, wherein properties of the steel slag powder meet the Grade II technical requirements in the standard GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete”.

[0015] As a preferred technical solution, the preparation process of the steel slag powder- ferromanganese ore slag powder composite admixture provided by the present disclosure further includes part or all of the following technical features:

[0016] As an improvement of the above technical solution, the steel slag powder has a median diameter Do, of smaller than or equal to 15 um and a specific surface area of 400-500 m?/kg.

[0017] As an improvement of the above technical solution, the ferromanganese ore slag powder has a median diameter Do, of smaller than or equal to 10 um and a specific surface area of 400- 600 m?/kg.

[0018] As an improvement of the above technical solution, in the step 1), a grinding aid with triethanolamine as a main component is blended in the grinding process, wherein a blending amount of the triethanolamine is 0.02%-0.05%.

[0019] Compared with the prior art, the technical solutions of the present disclosure have the following beneficial effects: by mixing the Grade II steel slag powder and the ferromanganese ore slag powder, the composite admixture with high early strength and continuously increased later strength 1s prepared by utilizing the mutual excitation and synergetic effect between the steel slag powder and the ferromanganese ore slag powder. The composite admixture can obviously improve the fluidity of cement cementing materials. In addition, the composite admixture of the present disclosure and the same mass of cement can be used to prepare C30-C50 high-strength concrete, which has good compressive strength. The composite admixture of the present disclosure can be mixed with the same mass of cement, so the blending amount is extremely large, which significantly improves the utilization rate and resource utilization level of solid waste and reduces the production cost of concrete materials.

[0020] The above description is only a general description of the technical solutions of the present disclosure. In order to understand the technical means of the present disclosure more clearly such that the technical means can be implemented in accordance with the content of the description, and to make the above and other objects, features and advantages of the present disclosure more comprehensible, a detailed description is given below in conjunction with preferred embodiments.

Brief Description of the Drawings

[0021] In order to describe the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings of the embodiments will be briefly introduced below.

[0022] FIG. 1 is an SEM image of 7d hydration products of a cement paste according to Embodiment 1 of the present disclosure;

[0023] FIG. 2 is an SEM image of 7d hydration products of a cement-steel slag powder composite admixture paste according to Embodiment 2 of the present disclosure;

[0024] FIG. 3 is an SEM image of 7d hydration products of a cement-steel slag powder- ferromanganese ore slag powder composite admixture paste according to Embodiment 6 of the present disclosure;

[0025] FIG. 4 is an SEM image of 28d hydration products of the cement paste according to Embodiment 1 of the present disclosure;

[0026] FIG. 5 is an SEM image of 28d hydration products of the cement-steel slag powder composite admixture paste according to Embodiment 2 of the present disclosure; and

[0027] FIG. 6 is an SEM image of 28d hydration products of the cement-steel slag powder- ferromanganese ore slag powder composite admixture paste according to Embodiment 6 of the present disclosure.

Detailed Description of the Embodiments

[0028] The detailed description of the embodiments of the present disclosure will be described in detail below. As a part of the description, the embodiments are used to illustrate the principles of the present disclosure, so that other aspects, features and advantages of the present disclosure 5 will become clear through the detailed description.

[0029] According to the present disclosure, by mixing the steel slag powder and the ferromanganese ore slag powder, the composite admixture with high early strength, continuously increased later strength and a shrinkage compensating effect is prepared by utilizing the mutual excitation and synergetic effect between the steel slag powder and the ferromanganese ore slag powder, so that the fluidity and compressive and flexural activities of the admixture in cement mortar are enhanced, the concrete slump with time is increased, and the compressive strength and flexural strength of the concrete are enhanced.

[0030] The ferromanganese ore slag powder-steel slag powder composite admixture of the present disclosure is prepared by the following process:

[0031] 1) Ferromanganese ore slag and steel slag are respectively dried, crushed, ground, and graded or sieved to obtain ferromanganese ore slag powder and steel slag powder.

[0032] Specifically, the ferromanganese ore slag is dried to a moisture content of less than 1%, and then crushed to a particle size of less than 4.75 mm by using a jaw crusher. Next, a 5 kg ball grinder is used for grinding, and 0.03% of triethanolamine grinding aid is blended in the grinding process. Finally, the mixture is allowed to pass through a 0.9 mm sieve to obtain the ferromanganese ore slag powder with a Blaine specific surface area of 456 m*/kg, a density of

2.81 g/cm and a median diameter D¢soy of smaller than or equal to 10 um.

[0033] The steel slag is dried to a moisture content of less than 1%, and then crushed to a particle size of less than 4.75 mm by using a jaw crusher. Next, a 5 kg ball grinder is used for grinding, and 0.03% of triethanolamine grinding aid is blended in the grinding process. Finally, the mixture is allowed to pass through a 0.9 mm sieve to obtain the steel slag powder with a Blaine specific surface area of 410 m?/kg, a density of 3.41 g/cm? and a median diameter D(soy of smaller than or equal to 15 um.

[0034] 2) The steel slag powder and the ferromanganese ore slag powder are uniformly mixed according to a certain ratio to obtain the ferromanganese ore slag powder-steel slag powder composite admixture.

[0035] <Table 1> Composition of steel slag powder-ferromanganese ore slag powder composite admixture

"Experiment Steel slag powder Ferromanganesc ore Cement Sand-to- ~~ Waler-to- No. (wt) slag g/(wt%o) g binder ratio binder ratio “Embodiment 0 o 40 13 05 Embodiment 2 135/0% 0 315 1:3 0.5 Embodiment 3 121.5/90% 13.5/10% 315 1:3 0.5 Embodiment 4 114.75/85% 20.25/15% 315 1:3 0.5 Embodiment 5 108/80% 27/20% 315 13 0.5 Embodiment 6 101.25/75% 33.75/25% 315 1:3 0.5 Embodiment 7 94.5/70% 40.5/30% 315 1:3 0.5

[0036] Referring to Table 2, the table reflects the chemical composition of ferromanganese ore slag micropowder and steel slag micropowder in the composite admixture.

[0037] The steel slag powder in the composite admixture of the present disclosure contains lots of CaO, Fe>Os and S102, while the ferromanganese ore slag micropowder mainly contains SiO, ALO, CaO and MnO. It can be seen that the ferromanganese ore slag powder contains more active components than the steel slag powder.

[0038] <Table 2> Chemical composition of ferromanganese ore slag micropowder and steel slag powder Category apg —m—m—m—m™m™m™mmm ov ALO; CaO MgO SiO; Fe20; POs MnO TiO, SO: LOI _ Ferromanganese ore powder 2.36 2190 1480 515 3223 192 0.01 12.59 027 193 3.53 Steel slag micropowder 2.29 3.64 3974 634 1551 20.61 182 437 086 025 2.78

[0039] Referring to Table 3, the table shows test results obtained after mixing the ferromanganese ore slag powder-steel slag powder composite admixture in various ratios and cement in Table 1 according to the weight ratio of 1:3, obtaining cement mortar according to the water-to-binder ratio of 0.5 and then performing a steel slag micropowder mortar test according to the standard GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete". For comparison, a cement mortar without the composite admixture of the present disclosure is prepared as a blank sample. Table 3 reflects that compared with the cement mortar (the blank sample) using cement alone, the fluidity of the cement mortars (Embodiment 2-Embodiment 7) blended with 30% of ferromanganese ore slag powder-steel slag powder composite admixture is

103.5%-106.5% of that of the blank sample. This indicates that the blending of the ferromanganese ore slag powder-steel slag powder composite admixture can obviously improve the fluidity of the cement.

[0040] <Table 3> Test results of cement mortar with steel slag powder-ferromanganese ore slag powder composite admixture PE 3dMPy WMP 2%dMPa) (mm) Flexural Compressive Flexural Compressive Flexural Compressive “Embodiment | 184.0 6.10 22.875 6.80 35.275 7.65 49.650 Embodiment

190.5 4.00 14.700 5.30 22.750 7.20 34.550 Embodiment 3 196.0 4.70 14.500 5.40 22.530 6.85 35.950 Embodiment 4 195.5 4.60 14.800 5.40 22.975 7.55 36.375 Embodiment 5 192.0 4.00 14.975 5.30 23.400 7.35 38.200 oomen 194.0 4.25 15.250 5.45 23.775 8.10 39.830 men 193.5 4.10 14.625 5.60 23.525 7.25 37.650

[0041] Referring to Table 4, Table 4 shows activity indexes obtained after processing the data 5 results of Table 3 according to the activity calculation method in the standard GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete". It can be seen that compared with the cement mortar (the blank sample) using cement alone, the compressive strength activity index and the flexural strength activity index of the cement mortars (Embodiment 2-Embodiment 7) blended with 30% of ferromanganese ore slag powder-steel slag powder composite admixture decrease. According to the technical requirements in GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete", the 7d activity index of the Grade I steel slag powder is not less than 65% and the 28d activity index of the Grade I steel slag powder is not less than 80%. The 7d activity index of the Grade II steel slag powder 1s not less than 55% and the 28d activity index of the Grade II steel slag powder is not less than 65%. The 7d and 28d activity indexes of the 6 samples in Embodiment 2-Embodiment 7 all meet the technical requirements for Grade II steel slag powder in GB/T20491-

2017. When Embodiment 6 is blended with 25% of ferromanganese ore slag micropowder, the 7d activity is 67.4% and the 28d activity is 80.3%, which meet the technical requirements for Grade I steel slag powder.

[0042] Embodiment 1, Embodiment 2 and Embodiment 6 in Table 1 are selected at the same time to make paste test blocks according to GB/T1346-2011 "Standard for Test Methods for Water Requirement of Normal Consistency, Setting Time and Soundness of the Portland Cement". After 28d of standard curing, the samples are made, and microstructures of the fresh sections of the samples at each hydration age are observed by a scanning electron microscope (SEM) in a vacuum mode, as shown in FIG. 1-FIG. 6. FIG. 1 reflects the microstructure of the hydration products of Embodiment 1 (the blank sample). It can be seen from FIG. 1 that the hydration products of pure cement paste after 7d of standard curing are mainly fibrous C-S-H gel and flaky CH, and there are lots of voids (black) and lots of unhydrated particles (white). FIG. 2 reflects the microstructure of the hydration products of Embodiment 2. It can be seen from FIG. 2 that the hydration products of the cement-steel slag powder paste after 7d of standard curing are still fibrous C-S-H gel and flaky CH, but the voids are significantly reduced, and the unhydrated part is also reduced as compared with the pure cement sample. FIG. 3 reflects the microstructure of the hydration products of Embodiment 6. It can be seen from FIG. 3 that the hydration products of the cement- steel slag powder-ferromanganese ore slag powder paste after 7d of curing are similar to those of the previous two groups, but the number of the voids is the smallest, and the unhydrated part is the least as compared with the previous two groups. It can be seen that after the steel slag powder and the ferromanganese ore slag powder are blended, the composite admixture produces more early hydration products and less unhydrated parts and voids, so the blending of the steel slag powder and the ferromanganese ore slag powder can promote the early hydration of the composite admixture.

[0043] FIG. 4 reflects the microstructure of the hydration products of Embodiment 1 (the blank sample). It can be seen from FIG. 4 that the section of the pure cement paste after 28d of standard curing is dense, and the C-S-H gel and CH are interwoven into a whole. At the same time, the net- like C-S-H gel is dense, so the cement mortar has a high strength at this time. FIG. 5 reflects the microstructure of the hydration products of Embodiment 2. It can be seen from FIG. 5 that compared with the section of the pure cement paste after 28d of standard curing, the section of the hydration products of the cement-steel slag powder paste after 28d of standard curing has more voids, and the C-S-H in the section is mainly of the shape of spherical particles and fibers, which shows that the composite admixture blended with the steel slag powder has a lower hydration degree than the pure cement sample. FIG. 6 reflects the microstructure of the hydration products of Embodiment 6. It can be seen from FIG. 6 that the section of the hydration products of the cement-steel slag powder-ferromanganese ore slag powder paste after 28d of standard curing is substantially the same as that of the pure cement sample, and the net-like C-S-H gel of the whole section is very dense, which shows that the blending of the ferromanganese ore slag powder effectively accelerates the hydration progress of the composite admixture, thereby indicating that the steel slag powder-ferromanganese ore slag powder-cement composite admixture has more excellent gelling properties than the traditional steel slag powder-cement composite admixture.

[0044] <Table 4> Test results of activity index of cement mortar with steel slag powder- ferromanganese ore slag powder composite admixture Fleir Compressiveactivityindex(%) Flesural activity index (%) Percentage % 3d 7d 28d 3d 7d 28d Embodiment 1 1 or 100.0% 100.0% 100.0% 100.0% 100.0% 0 Embodiment 2 103.5 04.3% 64.5% 09.6% 65.6% 77.9% 94.1% Embodiment 3 106.5 63.4% 63.9% 72.4% 77.1% 79.4% 89.5% Embodiment 4 106.3 64.7% 65.1% 73.3% 75.4% 79.4% 98.7% Embodiment 5 104.3 65.5% 66.3% 76.9% 05.6% 77.9% 96.1% Embodiment 6 105.4 06.7% 67.4% 80.3% 09.7% 80.1% 105.9% Embodiment 7 105.2 63.9% 66.7% 75.8% 67.2% 82.4% 94.8%

[0045] Table 5 shows a design scheme for commercial concrete with strength grades C30-C50. River sand with a fineness modulus of 3.4 is used as the fine aggregate, and continuous graded limestone gravel with a particle size of 5-25 mm is used as the coarse aggregate. The mix design is as follows: 16.0% of cement, 25.6% of natural river sand, 52.0% of gravel, 0.03% of water reducing agent and 6.4% of mixing water. The specific steps are as follows: 2502.5 g of P.O42.5 cement (the pure cement blank sample in Embodiment 8, and a mixture of 75% of steel slag powder and 25% of ferromanganese ore slag powder in replacement of 30% by weight of cement in Embodiment 9), 3991 g of natural river sand, 8105.5 g of gravel with a particle size of 5-25 mm (2026 g of gravel with a particle size of 5-10 mm, 4052 g of gravel with a particle size of 10-20 mm and 2026 g of gravel with a particle size of 20-25 mm), 4.0 g of polycarboxylic acid water reducing agent and 1001 g of mixing water are weighed, then sequentially placed in a concrete mixer and uniformly mixed. Then, according to GB/T50081-2002 "Standard for Test Method of Mechanical Properties on Ordinary Concrete", concrete test blocks are prepared, and slump, slump with time, compressive strength, flexural strength and the like are detected. The mechanical property test results are shown in Table 5.

[0046] <Table 5> Test results of mechanical properties of water concrete with the steel slag powder-ferromanganese ore slag powder composite admixture ~ No. Slmp(mm) Compressive strength (MPa) Flexural strength (MPa)

“Initial Afterlh 7d 28d 60d 90d 7d 28d 60d 90d “Embodiment 95 49 411 482 555 625 37 44 50 S54 Embodiment 9 100 64 281 434 465 52.6 2.4 33 4.0 4.5

[0047] It can be seen from Table 5 that both the initial slump and the slump with time, especially the slump with time, of Embodiment 9 increase as compared with the blank sample (Embodiment 8). The compressive and flexural strengths decrease slightly, but they all meet the design standards.

[0048] Compared with the prior art, according to the present disclosure, by mixing the Grade II steel slag powder and the ferromanganese ore slag powder, the composite admixture with high early strength and continuously increased later strength is prepared by utilizing the mutual excitation and synergetic effect between the steel slag powder and the ferromanganese ore slag powder. The composite admixture can obviously improve the fluidity of cement cementing materials. In addition, the composite admixture of the present disclosure and the same mass of cement can be used to prepare C30-C50 high-strength concrete, which has good compressive strength. The composite admixture of the present disclosure can be mixed with the same mass of cement, so the blending amount is extremely large, which significantly improves the utilization rate and resource utilization level of solid waste and reduces the production cost of concrete materials.

[0049] The raw materials listed in the present disclosure, the upper and lower limits and interval values of the raw materials of the present disclosure, and the upper and lower limits and interval values of the process parameters (such as temperature, time and the like) can all realize the present disclosure, and the embodiments are not listed here.

[0050] The above is only the preferred embodiments of the present disclosure. Of course, the scope of the present disclosure cannot be limited by this. It should be noted that those of ordinary skill in the art can make several improvements and changes without departing from the principle of the present disclosure, and these improvements and changes are also deemed to be within the protection scope of the present disclosure.

Claims

CONCLUSIESCONCLUSIONS

1. Een composietmengsel van staalslakpoeder en ferromangaanerts, bestaande uit de volgende componenten in gewichtsprocent: 5 % tot 30 % slakkenpoeder ferromangaanerts en 70 % tot 95 % staalslakpoeder, waarbij de eigenschappen van het staalslakpoeder voldoen aan de Grade II technische eisen in de norm GB/T2049 1-2017 "Steel Slag Powder Used for Cement and Concrete”.1. A composite mixture of steel slag powder and ferromanganese ore, consisting of the following components by weight: 5 % to 30 % slag powder ferromanganese ore and 70 % to 95 % steel slag powder, the properties of the steel slag powder meeting the Grade II technical requirements in standard GB/ T2049 1-2017 “Steel Slag Powder Used for Cement and Concrete”.

2. Het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het staalslakpoeder een mediaandiameter D(s0) heeft die kleiner is dan of gelijk is aan 15 um.The composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein the steel slag powder has a median diameter D(s0) which is less than or equal to 15 µm.

3. Het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het ferromangaanerts-slakpoeder een mediaandiameter Do, heeft die kleiner is dan of gelijk is aan 10 um.The composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein the ferro-manganese ore-slag powder has a median diameter Do 1 which is less than or equal to 10 µm.

4. Het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het staalslakpoeder een soortelijke oppervlakte heeft van 400 tot 500 m?/kg.The composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein the steel slag powder has a specific surface area of 400 to 500 m 2 /kg.

5. Het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het ferromangaanerts-slakpoeder een soortelijke oppervlakte heeft van 400 tot 600 m?/kg.The composite mixture of steel slag powder and ferromanganese ore according to claim 1, wherein the ferromanganese ore-slag powder has a specific surface area of 400 to 600 m 2 /kg.

6. Een bereidingswijze van het composietmengsel van staalslakpoeder en ferromangaanerts bestaande uit de volgende stappen: 1) het drogen, pletten, malen en sorteren of zeven van ferromangaanerts-slakken en staalslakken om ferromangaanerts-slakpoeder en staalslakpoeder te verkrijgen; en 2) het gelijkmatig mengen van het ferromangaanerts-slakpoeder en het staalslakpoeder volgens gewichtspercentages van 5 % tot 30 % en 70 % tot 95 % om het composietmengsel van staalslakpoeder en ferromangaanerts-slakpoeder te bekomen, waarbij de eigenschappen van het staalslakpoeder voldoen aan de technische eisen van Grade II in de norm GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete".6. A method of preparing the composite mixture of steel slag powder and ferro-manganese ore comprising the following steps: 1) drying, crushing, grinding and sorting or screening ferro-manganese ore-slag and steel-slag to obtain ferro-manganese ore-slag powder and steel-slag powder; and 2) evenly mixing the ferro-manganese ore-slag powder and the steel-slag powder according to weight percentages of 5% to 30% and 70% to 95% to obtain the composite mixture of steel-slag powder and ferro-manganese ore-slag powder, whereby the properties of the steel-slag powder meet the technical specifications. Grade II requirements in GB/T20491-2017 "Steel Slag Powder Used for Cement and Concrete".

7. De bereidingswijze van het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het staalslakpoeder een mediaandiameter Dyso) heeft die kleiner is dan of gelijk is aan 15 pum en een soortelijke oppervlakte van 400 tot 500 m?kg.The preparation method of the composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein the steel slag powder has a median diameter Dyso) less than or equal to 15 µm and a specific surface area of 400 to 500 m 2 kg.

8. De bereidingswijze van het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij het ferromangaanerts-slakpoeder een mediaandiameter D(so) heeft die kleiner is dan of gelijk is aan 10 pm en een soortelijke oppervlakte van 400 tot 600 m?/kg.The preparation method of the composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein the ferro-manganese ore-slag powder has a median diameter D(50) less than or equal to 10 µm and a specific surface area of 400 to 600 m 2 /kg.

9. De bereidingswijze van het composietmengsel van staalslakpoeder en ferromangaanerts volgens conclusie 1, waarbij in de stap 1) een maalhulpstuk met triéthanolamine als hoofdbestanddeel in het maalproces wordt gemengd, waarbij een menghoeveelheid van de triëthanolamine 0,02% tot 0,05 % is.The preparation method of the composite mixture of steel slag powder and ferro-manganese ore according to claim 1, wherein in the step 1), a milling attachment having triethanolamine as the main component is mixed in the milling process, wherein a mixing amount of the triethanolamine is 0.02% to 0.05%.