Low-shrinkage steel slag powder mine filling cementing material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of mine filling materials, and provides a low-shrinkage steel slag powder mine filling cementing material and a preparation method and application thereof.The cementing material is prepared from, by weight, 30-40 parts of steel slag powder, 50-60 parts of mineral powder, 8-15 parts of desulfurized gypsum and 0-5 parts of excitant, the excitant is superfine cement clinker, and the specific surface area is larger than or equal to 600 m < 2 > / kg; through a cascade reaction path of early excitation, expansion compensation and continuous enhancement among the components such as the steel slag powder, the mineral powder and the desulfurized gypsum, the filling cementing material which is high in solid waste mixing amount, low in shrinkage and appropriate in strength and has environmental protection benefits and engineering applicability is realized, pollution and carbon are reduced, cost is reduced and benefits are increased for tailing treatment, and the filling cementing material is suitable for being used as a filling cementing material. And the comprehensive utilization way of the tailings and the metallurgical solid waste is further expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of mine filling materials, in particular to a low-shrinkage steel slag powder mine filling gelling material and a preparation method and application thereof. Background Art

[0002] Non-ferrous metal ores generally have a low content of useful minerals and fine embedded particle size. The tailings discarded during the mineral processing process are one of the main solid wastes in mines. The current backfill mining method is the preferred method for metal mining, but traditional mine backfill materials mostly use cement-based gelling materials, which have problems such as high cost, large shrinkage rate, and low solid waste utilization rate. Steel slag, as an industrial solid waste, has potential gelling and micro-expansion properties, and the strength required for mine filling materials is relatively low. Steel slag powder can fully meet this demand. In addition, the micro-expansion properties of steel slag powder can better compensate for the volume shrinkage of the mine, thereby increasing the volume stability of mine filling. The utilization rate of steel slag in the existing technology is low, and it does not effectively cooperate with other solid wastes (such as slag and desulfurization gypsum) to optimize performance. Therefore, there is an urgent need to develop a new mine backfill gelling material to solve the problems existing in the existing technology. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a low-shrinkage steel slag powder mine filling cementitious material and its preparation method and application, which are used to solve the problems of high mine filling cost, large shrinkage rate of filling material and low solid waste utilization rate in the prior art.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a low-shrinkage steel slag powder mine filling cementitious material, comprising the following components in parts by weight:

[0005] 30-40 parts of steel slag powder;

[0006] 50-60 parts of mineral powder;

[0007] 8-15 parts of desulfurized gypsum;

[0008] 0-5 parts of stimulant;

[0009] The activator is ultrafine cement clinker with a specific surface area of ≥600m 2 / kg.

[0010] The present invention also provides a method for preparing the low-shrinkage steel slag powder mine filling cementitious material as described above, comprising the following steps:

[0011] Steel slag powder, mineral powder, desulfurized gypsum and activator are uniformly mixed according to a proportion to obtain low shrinkage steel slag powder mine filling cementitious material.

[0012] The present invention also provides an application of the low-shrinkage steel slag powder mine filling gelling material in the field of mine filling.

[0013] As described above, the low-shrinkage steel slag powder mine filling cementitious material of the present invention and its preparation method and application have the following beneficial effects:

[0014] The low-shrinkage steel slag powder mine filling cementitious material of the present invention comprises steel slag powder, mineral powder, desulfurized gypsum, and an activator. It is used as a binder for mountain filling materials during mining operations, achieving performance optimization through a multi-component synergistic mechanism: the steel slag powder serves as the core cementing phase, imparting early-stage cementitious properties to the system and generating moderate micro-expansion, effectively compensating for the curing shrinkage of the filling. The vitreous silica-alumina in the mineral powder synergizes with the sulfate ions provided by the desulfurized gypsum to continuously generate secondary ettringite and CSH gel in the late hydration stage, forming a dense network structure that enhances later strength growth. The ultrafine cement clinker-type activator rapidly hydrates through highly active tricalcium silicate, reacting with the steel slag to form a dual-cementitious system, significantly improving the material's early strength. Through a cascade reaction pathway of "early activation-expansion compensation-continuous enhancement," each component achieves a filling cementitious material with high solid waste content, low shrinkage, appropriate strength, and both environmental benefits and engineering applicability.

[0015] The present invention develops and produces mine filling cementitious materials from metallurgical solid waste such as steel slag and applies them to the field of filling tailings goaf areas, replacing the use of most highly polluting cements. This not only reduces pollution and carbon emissions, reduces costs and increases efficiency in tailings management, but also further expands the comprehensive utilization of tailings and metallurgical solid wastes. DETAILED DESCRIPTION

[0016] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0017] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all subranges between a minimum of 1 and a maximum of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, and the like.

[0018] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; and, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of implementation of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0019] A first aspect of the present invention provides a low-shrinkage steel slag powder mine filling cementitious material, comprising the following components in parts by weight:

[0020] 30 to 40 parts of steel slag powder; for example, 30 to 32 parts, 32 to 34 parts, 34 to 35 parts, 35 to 36 parts, 36 to 38 parts, or 38 to 40 parts;

[0021] 50-60 parts of mineral powder; for example, 50-52 parts, 52-54 parts, 54-55 parts, 55-56 parts, 56-58 parts or 58-60 parts of desulfurization gypsum 8-15 parts; for example, 8-10 parts, 10-12 parts, 12-14 parts or 14-15 parts;

[0022] 0-5 parts of stimulator; for example, 0-1, 1-2, 2-3, 3-4 or 4-5 parts;

[0023] The activator is ultrafine cement clinker with a specific surface area of ≥600m 2 / kg. Using ultrafine cement clinker as an activator can significantly increase hydration activity, enhance the early strength of mine fillings, improve density and durability, and optimize anti-seepage and anti-corrosion properties.

[0024] In a preferred embodiment of the present invention, the low shrinkage steel slag powder mine filling cementitious material comprises the following components in parts by weight:

[0025] 35-40 parts of steel slag powder;

[0026] 50-55 parts of mineral powder;

[0027] 8-12 parts of desulfurized gypsum;

[0028] 0 to 3 parts of stimulant.

[0029] In the present invention, the free calcium oxide in the steel slag powder is less than 3%, and the specific surface area is ≥400m 2 / kg. The specific surface area is increased to 400m3 through ultra-fine grinding process. 2 / kg, inducing lattice distortion on the particle surface, effectively exposing hydration active sites and enhancing the activity of the slag. Controlling free calcium oxide to below 3% effectively inhibits later expansion and cracking, ensuring the volume stability of the filling, while leveraging the dual advantages of micro-expansion compensating for shrinkage and hydraulic gelling enhancing stability.

[0030] In the present invention, the mineral powder is S95 grade mineral powder.

[0031] In the present invention, the desulfurization gypsum is semi-hydrated desulfurization gypsum with a specific surface area of ≥400m 2 / kg. It can improve gelling activity and enhance later strength.

[0032] A second aspect of the present invention provides a method for preparing the low-shrinkage steel slag powder mine filling cementitious material as described above, comprising the following steps:

[0033] Steel slag powder, mineral powder, desulfurized gypsum and activator are uniformly mixed according to a proportion to obtain low shrinkage steel slag powder mine filling cementitious material.

[0034] In the preparation method of the present invention, the steel slag powder is obtained by subjecting steel slag raw materials to magnetic separation for iron removal, and then drying steel slag with free calcium oxide less than 3%.

[0035] In a preferred embodiment of the present invention, the magnetic separation is to remove iron so that the metallic iron content is ≤1.5%. Controlling the metallic iron content to a low level can improve volume stability and durability, enhance gelling activity and reduce corrosion risks, ensuring stable and reliable performance of the steel slag powder.

[0036] In a preferred embodiment of the present invention, the drying is performed to reduce the moisture content to ≤1%. When grinding steel slag, a low moisture content can reduce equipment sticking and clogging, improve grinding efficiency, reduce energy consumption, and facilitate material flow and control of product fineness.

[0037] In the preparation method of the present invention, the steel slag powder is first ground before mixing, and ground to a specific surface area of ≥400m 2 / kg.

[0038] In the preparation method of the present invention, the stimulant is first ground before mixing, and ground to a specific surface area of ≥600m 2 / kg.

[0039] In the preparation method of the present invention, the desulfurized gypsum is first ground before mixing, and ground to a specific surface area of ≥400m 2 / kg.

[0040] In the preparation method of the present invention, the mixing is carried out in a mixer.

[0041] In the preparation method of the present invention, the mixing time is 10 to 20 minutes, for example, 10 to 15 minutes or 15 to 20 minutes.

[0042] A third aspect of the present invention provides an application of the low-shrinkage steel slag powder mine filling cementitious material as described above in the field of mine filling.

[0043] The low shrinkage steel slag powder mine filling cementitious material provided by the present invention, its preparation method and application are described in detail below with reference to the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] Steel slag powder (free calcium oxide <3%, specific surface area ≥400m 2 / kg) 52.5Kg, S95 grade mineral powder 82.5Kg, semi-hydrated desulfurized gypsum (specific surface area ≥ 400m 2 / kg) 12Kg, ultra-fine cement clinker (specific surface area ≥ 600m 2 / kg) 3 kg was mixed in a mixer for 15 min and mixed evenly to obtain a low-shrinkage steel slag powder mine filling cementitious material.

[0046] The low-shrinkage steel slag powder mine filling cementitious material was mixed with 750 kg of tungsten tailings and 300 kg of water, stirred evenly, and poured into a mortar mold to form a filling module. Excess slurry was scraped off, the surface was smoothed horizontally, and then compacted vertically to a finish. Curing was carried out at 20 ± 1°C and a humidity of ≥ 90%. The strength and shrinkage of the filling module were tested after 3, 7, and 28 days of curing. The test results are shown in Table 2.

[0047] Example 2

[0048] The difference from Example 1 is that: 60 kg of steel slag powder, 75 kg of S95 grade mineral powder, 12 kg of semi-hydrated desulfurized gypsum, and 3 kg of ultrafine cement clinker were used, and the rest was the same as Example 1. The test results are shown in Table 2.

[0049] Example 3

[0050] The difference from Example 1 is that: 46.5 kg of steel slag powder, 81 kg of S95 grade mineral powder, 16.5 kg of semi-hydrated desulfurized gypsum, and 6 kg of ultrafine cement clinker are used, and the rest is the same as Example 1. The test results are shown in Table 2.

[0051] Example 4

[0052] The difference from Example 1 is that: 45 kg of steel slag powder, 82.5 kg of S95 grade mineral powder, 22.5 kg of semi-hydrated desulfurized gypsum, and 0 kg of ultrafine cement clinker are used, and the rest is the same as Example 1. The test results are shown in Table 2.

[0053] Example 5

[0054] The difference from Example 1 is that: 57 kg of steel slag powder, 75 kg of S95 grade mineral powder, 15 kg of semi-hydrated desulfurized gypsum, and 3 kg of ultrafine cement clinker are used, and the rest is the same as Example 1. The test results are shown in Table 2.

[0055] Example 6

[0056] The difference from Example 1 is that: 48 kg of steel slag powder, 90 kg of S95 grade mineral powder, 12 kg of semi-hydrated desulfurized gypsum, and 0 kg of ultrafine cement clinker are used, and the rest is the same as Example 1. The test results are shown in Table 2.

[0057] Comparative Example 1

[0058] The difference from Example 1 is that the specific surface area of the steel slag powder is 300m 2 / kg, and the rest is the same as in Example 1. The test results are shown in Table 2.

[0059] Comparative Example 2

[0060] The difference from Example 1 is that: 75 kg of steel slag powder, 63 kg of S95 grade mineral powder, 12 kg of semi-hydrated desulfurized gypsum, and 0 kg of ultrafine cement clinker are used, and the rest are the same as Example 1. The test results are shown in Table 2.

[0061] Comparative Example 3

[0062] The difference from Example 1 is that: 49.5 kg of steel slag powder, 76.5 kg of S95 grade mineral powder, 12 kg of semi-hydrated desulfurized gypsum, and 12 kg of ultrafine cement clinker are used, and the rest is the same as Example 1. The test results are shown in Table 2.

[0063] Comparative Example 4

[0064] The differences from Example 1 are as follows: 60 kg of steel slag powder, 60 kg of S95-grade slag powder, 30 kg of semi-hydrated desulfurized gypsum, and 0 kg of ultrafine cement clinker; the resulting low-shrinkage steel slag powder mine filling cementitious material is mixed with 750 kg of tungsten tailings and 360 kg of water. The remaining ingredients are the same as in Example 1. The test results are shown in Table 2.

[0065] The proportion formula and slurry concentration of the above embodiments and comparative examples are shown in Table 1. The tungsten tailings sand in the above embodiments and comparative examples is the aggregate of the filling module, and the slurry concentration = (aggregate + cementitious material) / (aggregate + cementitious material + water) * 100%.

[0066] Table 1

[0067]

[0068] The tungsten tailings in the above examples and comparative examples come from Xianglushan Tungsten Industry, a subsidiary of Tungsten High-tech Materials Co., Ltd.; the steel slag powder comes from Nanjing Iron and Steel Co., Ltd.; the slag powder comes from Shanghai Baotian New Building Materials Co., Ltd.; the desulfurization gypsum comes from Yantai Anda Environmental Protection Technology Co., Ltd.; and the ultrafine cement clinker comes from Anhui Conch Cement Co., Ltd.

[0069] The lime-sand ratio of the filler in the above embodiments and comparative examples is 1:5.

[0070] Performance testing:

[0071] The filling modules prepared in the above examples and comparative examples were tested for compressive strength according to GB / T 17671-2021; shrinkage according to JC / T 603-2004; and initial setting time according to GB / T 50080. The results are shown in Table 2.

[0072] Table 2

[0073]

[0074]

[0075] Combining the data of Examples 1 to 6 and Table 2, it can be seen that the filling material module prepared by using the low-shrinkage steel slag powder mine filling cementitious material of the present invention fully complies with the requirements of GB / T 39489-2020 "Technical Specifications for Full Tailings Paste Filling" and has a shrinkage rate of less than 0.5%.

[0076] The steel slag powder used in Comparative Example 1 has a specific surface area of 300m 2 / kg, compared with Example 1, the hydration activity of the steel slag powder is low, resulting in a significant decrease in early and late strength.

[0077] In Comparative Example 2, the amount of steel slag powder used was too large, reaching 50% of the cementitious material, resulting in a long setting time and reduced strength.

[0078] In Comparative Example 3, the amount of activator used is too large, reaching 8% of the cementitious material, resulting in a too short setting time of the filling material, which is inconvenient for filling operations. Moreover, the activator is more expensive than other components, and excessive use will increase the filling cost.

[0079] In Comparative Example 4, the amount of desulfurized gypsum used is too large, reaching 20% of the cementitious material, which increases the amount of water used and causes the shrinkage of the filling material to increase in the later stage, affecting the supporting performance of the filling material.

[0080] It can be seen from Examples 1 to 6 that the low-shrinkage steel slag powder mine filling cementitious material of the present invention, under the premise of complying with national standards, can give full play to the cementitiousness and micro-expansion of steel slag powder, reduce the shrinkage rate of the filling material, improve the safety of mine filling, and at the same time synergistically utilize solid waste blast furnace slag and desulfurization gypsum to reduce filling costs.

[0081] Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0082] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may 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 one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A low shrinkage steel slag powder mine filling cementitious material, characterized in that: It comprises the following components in parts by weight: 30-40 parts of steel slag powder; 50-60 parts of mineral powder; 8-15 parts of desulfurized gypsum; 0-5 parts of stimulant; The activator is ultrafine cement clinker with a specific surface area of ≥600m 2 / kg.

2. The low shrinkage steel slag powder mine filling cementitious material according to claim 1, characterized in that: It comprises the following components in parts by weight: 35-40 parts of steel slag powder; 50-55 parts of mineral powder; 8-12 parts of desulfurized gypsum; 0 to 3 parts of stimulant.

3. The low shrinkage steel slag powder mine filling cementitious material according to any one of claims 1 to 2, characterized in that: The free calcium oxide in the steel slag powder is less than 3%, and the specific surface area is ≥400m 2 / kg; And / or, the mineral powder is S95 grade mineral powder; And / or, the desulfurization gypsum is semi-hydrated desulfurization gypsum with a specific surface area of ≥400m 2 / kg.

4. A method for preparing a low-shrinkage steel slag powder mine filling cementitious material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Steel slag powder, mineral powder, desulfurized gypsum and activator are uniformly mixed according to a proportion to obtain low shrinkage steel slag powder mine filling cementitious material.

5. The method for preparing low shrinkage steel slag powder mine filling cementitious material according to claim 4, characterized in that: The steel slag powder is obtained by subjecting steel slag raw materials to magnetic separation for iron removal, and then drying steel slag with free calcium oxide less than 3%.

6. The method for preparing low shrinkage steel slag powder mine filling cementitious material according to claim 5, characterized in that: The magnetic separation iron removal is to reduce the metallic iron content to ≤1.5%; And / or, the drying is performed to make the moisture content ≤1%.

7. The method for preparing low shrinkage steel slag powder mine filling cementitious material according to claim 4, characterized in that: The steel slag powder is ground before mixing to a specific surface area of 400m 2 / kg.

8. The method for preparing low shrinkage steel slag powder mine filling cementitious material according to claim 4, characterized in that: The activator is ground before mixing to a specific surface area of 600 m 2 / kg; And / or, the desulfurized gypsum is ground before mixing to a specific surface area of ≥400m 2 / kg.

9. The method for preparing low shrinkage steel slag powder mine filling cementitious material according to claim 4, characterized in that: The mixing is carried out in a mixer; And / or, the mixing time is 10 to 20 minutes.

10. Use of the low shrinkage steel slag powder mine filling cementitious material according to any one of claims 1 to 3 in the field of mine filling.

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