Alkali-activated lithium mica slag tailings concrete and method of making same

Abstract

This invention discloses an alkali-activated lithium mica tailings concrete and its preparation method, relating to the field of building materials technology. The alkali-activated lithium mica tailings concrete comprises the following raw materials in parts by weight: 0-168 parts lithium mica tailings, 252-420 parts slag, 656 parts fine aggregate, 1027 parts coarse aggregate, 60 parts solid alkali activator, and 240 parts water. This invention enables the resource utilization of solid waste from the lithium industry. This concrete does not contain cement clinker, thus reducing carbon emissions compared to traditional cement concrete. Simultaneously, the lithium mica tailings can replace some natural river sand, reducing the consumption of natural sand and gravel resources. Using anhydrous sodium silicate as a solid alkali activator avoids the corrosiveness and storage inconvenience problems associated with liquid alkali activators.

Description

Technical Field

[0001] This invention relates to the field of building materials, and in particular to an alkali-activated lithium mica tailings concrete and its preparation method. Background Technology

[0002] With the rapid development of the lithium battery industry, the large amounts of industrial solid waste generated during lithium extraction from lepidolite, such as lepidolite slag and tailings, have become a significant factor affecting the industry's sustainable development. These solid wastes are typically disposed of through stockpiling, which not only occupies substantial land resources but also poses potential environmental pollution risks. Meanwhile, the traditional concrete industry's reliance on natural sand and gravel resources and cement clinker has led to high resource consumption and carbon emissions. Therefore, the resource utilization of solid wastes such as lepidolite slag and tailings in the building materials sector, especially as cementitious materials or aggregate substitutes in the preparation of low-carbon concrete, is a promising area for development.

[0003] In the field of alkali-activated cementitious materials, some studies have attempted to prepare low-carbon cementitious materials using industrial solid waste.

[0004] CN111606612A discloses an alkali-activated cementitious material that uses sodium aluminate and sodium silicate as a solid alkali activator, which solves the problems of complicated construction and strong corrosiveness of liquid alkali activators. However, it only utilizes slag and does not involve lithium mica slag and tailings, so the types of solid waste utilized are limited. In addition, the material is a paste system and does not form a complete concrete mix proportion.

[0005] CN114605113A discloses a lithium slag concrete prepared using pure industrial waste residue, achieving 100% utilization of solid waste. However, its aggregates are entirely dependent on steel slag, the source of aggregates is limited, and the alkali activator usually contains strong alkalis, which are corrosive and the mix proportions are complex.

[0006] CN118745085A discloses a lithium slag-based alkali-activated cementitious material that synergistically utilizes multiple solid wastes, but the mix design is relatively complex, the alkali activator contains hydroxides and is highly corrosive, and lithium mica tailings are not included as fine aggregate in the system.

[0007] CN117735899A discloses a composite activated solid waste-based cemented lepidolite ultrafine tailings filler. Although it utilizes lepidolite tailings, it requires high-temperature and high-pressure steam activation, which requires high energy consumption or a complex process.

[0008] CN115259766A and CN120829273A respectively disclose alkali-activated fly ash concrete and its preparation method. However, the former has an extremely complex mix proportion, requires a variety of admixtures and high temperature and high pH conditions, while the latter requires steam curing and the addition of nanomaterials, resulting in higher costs. Neither of them involves the utilization of lithium mica slag and tailings.

[0009] In summary, the existing technology has the following problems in this field:

[0010] (1) Insufficient utilization of solid waste or limited sources: Some technologies only utilize single solid wastes such as slag and fly ash, without simultaneously disposing of two typical solid wastes in the lithium industry: lithium mica slag and lithium mica tailings; others utilize multiple solid wastes, but the aggregates are entirely dependent on specific industrial wastes such as steel slag, which are limited in source and difficult to promote on a large scale.

[0011] (2) The alkaline activation system is corrosive and has construction difficulties: Most technologies use liquids or strong alkaline activators such as water glass and sodium hydroxide, which have problems such as strong corrosivity, difficulty in storage and transportation, and complex construction procedures, which increase the safety risks and operational difficulties of engineering applications.

[0012] (3) Complex mixing ratio or harsh preparation process: Some existing technologies require the addition of various additives such as water-reducing agents, nanomaterials, and fibers, resulting in complex mixing ratio design; or require harsh conditions such as high-temperature steam curing and high-pressure steam curing, which result in high energy consumption and high equipment requirements, making them unsuitable for engineering applications.

[0013] (4) Incomplete concrete system: Some studies only focus on cementitious materials (cement paste) and have not formed a complete concrete mix proportion that includes coarse and fine aggregates. This is disconnected from actual engineering applications and is difficult to apply directly to structural concrete engineering.

[0014] (5) Insufficient attention to the aggregate utilization of lepidolite tailings: Existing technologies mostly use lepidolite tailings as cementing components or fillers, but rarely use them as fine aggregates to replace natural river sand in concrete systems, thus failing to fully realize their resource value as aggregates.

[0015] Therefore, developing a low-carbon concrete that can simultaneously absorb lepidolite slag and tailings, uses a safe and easy-to-use solid alkali activator, has a simple mix design, and possesses good mechanical properties is a technical issue worthy of attention in this field. Summary of the Invention

[0016] To address the issue of large-scale utilization of lepidolite slag and tailings, this invention provides an alkali-activated lepidolite slag tailings concrete and its preparation method.

[0017] The technical solution of the present invention:

[0018] An alkali-activated lithium mica tailings concrete comprises the following components in parts by weight: 42-168 parts lithium mica tailings, 252-420 parts slag, 656 parts fine aggregate, 1027 parts coarse aggregate, 60 parts solid alkali activator, and 240 parts water.

[0019] Furthermore, the lithium mica slag is dried at 105°C and ground in a ball mill for 30 minutes.

[0020] Furthermore, the fine aggregate is composed of lepidolite tailings and river sand, wherein the mass percentage of lepidolite tailings is 0-30%; the coarse aggregate is crushed stone.

[0021] Furthermore, the solid alkali activator is anhydrous sodium silicate with a modulus of 1.4.

[0022] A method for preparing alkali-activated lithium mica tailings concrete includes the following preparation steps:

[0023] Step 1: Weigh each raw material according to the mixing ratio;

[0024] Step 2: Add the coarse aggregate and fine aggregate to the mixing equipment in sequence and mix evenly;

[0025] Step 3: Add the lithium mica slag, blast furnace slag, and solid alkali activator to the mixing equipment in sequence and mix evenly;

[0026] Step 4: Add water to the mixing equipment and mix well;

[0027] Step 5: Pour the mixture into a mold or spread it out to solidify and shape.

[0028] Furthermore, the stirring time in step two is 90 seconds; the stirring time in step three is 90 seconds; and the stirring time in step four is 3 minutes.

[0029] The present invention has the following beneficial effects:

[0030] (1) Replacing part of the slag with lepidolite slag and part of the river sand with lepidolite tailings to prepare alkali-activated concrete can realize the resource utilization of lepidolite slag and lepidolite tailings and reduce their stockpiling requirements. This concrete does not contain cement clinker, which can reduce carbon emissions compared with traditional cement concrete, and at the same time reduce the consumption of natural sand and gravel resources.

[0031] (2) Using anhydrous sodium silicate as a solid alkali activator avoids the problems of corrosiveness and inconvenient transportation compared to liquid alkali activators, which is beneficial for engineering applications. Detailed Implementation

[0032] To better understand the present invention, preferred embodiments are described below. These preferred embodiments are used to illustrate and explain the invention, but are not intended to limit the invention. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. The modulus (SiO2 / Na2O molar ratio) of the anhydrous sodium silicate is 1.4, which provides a better alkali activation effect.

[0033] Example 1

[0034] This embodiment provides an alkali-activated lithium mica tailings concrete and its preparation method.

[0035] In this embodiment, the mix proportion of alkali-activated lepidolite tailings concrete is as follows: 42 parts lepidolite tailings, 378 parts slag, 132 parts lepidolite tailings, 525 parts river sand, 1027 parts crushed stone, 60 parts anhydrous sodium silicate, and 240 parts water. The specific preparation steps are as follows:

[0036] Step 1: Weigh each raw material according to the mixing ratio;

[0037] Step 2: Add the crushed stone, lepidolite tailings, and river sand to the mixing equipment in sequence and mix for 90 seconds;

[0038] Step 3: Add the lithium mica slag, blast furnace slag, and anhydrous sodium silicate to the mixing equipment in sequence and mix for 90 seconds;

[0039] Step 4: Add water to the mixing device and stir for 3 minutes;

[0040] Step 5: Pour the mixture into a mold, vibrate it, and then cover it with a film to cure at room temperature. After reaching the set age, conduct mechanical property tests.

[0041] Example 2

[0042] This embodiment provides an alkali-activated lithium mica tailings concrete and its preparation method.

[0043] In this embodiment, the mix proportion of alkali-activated lepidolite tailings concrete is as follows: 168 parts lepidolite tailings, 252 parts slag, 197 parts lepidolite tailings, 459 parts river sand, 1027 parts crushed stone, 60 parts anhydrous sodium silicate, and 240 parts water. The specific preparation steps are as follows:

[0044] Step 1: Weigh each raw material according to the mixing ratio;

[0045] Step 2: Add the crushed stone, lepidolite tailings, and river sand to the mixing equipment in sequence and mix for 90 seconds;

[0046] Step 3: Add the lithium mica slag, blast furnace slag, and anhydrous sodium silicate to the mixing equipment in sequence and mix for 90 seconds;

[0047] Step 4: Add water to the mixing device and stir for 3 minutes;

[0048] Step 5: Pour the mixture into a mold, vibrate it, and then cover it with a film to cure at room temperature. After reaching the set age, conduct mechanical property tests.

[0049] Comparative Example 1

[0050] This comparative example provides an alkali-activated lithium mica tailings concrete and its preparation method.

[0051] In this embodiment, the mix proportion of alkali-activated lithium mica tailings concrete is 420 parts slag, 656 parts river sand, 1027 parts crushed stone, 60 parts anhydrous sodium silicate, and 240 parts water. The specific preparation steps are as follows:

[0052] Step 1: Weigh each raw material according to the mixing ratio;

[0053] Step 2: Add the crushed stone and river sand to the mixing equipment in sequence and mix for 90 seconds;

[0054] Step 3: Add the lithium mica slag, blast furnace slag, and anhydrous sodium silicate to the mixing equipment in sequence and mix for 90 seconds;

[0055] Step 4: Add water to the mixing device and stir for 3 minutes;

[0056] Step 5: Pour the mixture into a mold, vibrate it, and then cover it with a film to cure at room temperature. After reaching the set age, conduct mechanical property tests.

[0057] The mechanical property test results of the alkali-activated lithium mica tailings concrete prepared in Example 1, Example 2, and Comparative Example 1 are shown in the table below:

[0058]

[0059] As can be seen from the table above, the concrete in the embodiments of the present invention has a high compressive strength. Partial replacement of slag with lepidolite slag and partial replacement of river sand with lepidolite tailings can improve the compressive strength of alkali-activated concrete, reaching the C30 strength grade. When the replacement rate is high, the compressive strength of the concrete does not decrease much and can still reach the C25 strength grade, indicating that the concrete has the potential for application in engineering.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An alkali-activated lepidolite tailings concrete, characterized in that, The components include the following parts by weight: 42-168 parts of lithium mica slag, 252-420 parts of slag, 656 parts of fine aggregate, 1027 parts of coarse aggregate, 60 parts of solid alkali activator, and 240 parts of water.

2. The alkali-activated lithium mica tailings concrete according to claim 1, characterized in that, The lithium mica residue was dried at 105°C and then ground in a ball mill for 30 minutes.

3. The alkali-activated lithium mica tailings concrete according to claim 1, characterized in that, The fine aggregate consists of lepidolite tailings and river sand, wherein the mass percentage of lepidolite tailings is 0-30%; the coarse aggregate is crushed stone.

4. The alkali-activated lithium mica tailings concrete according to claim 1, characterized in that, The solid alkali activator is anhydrous sodium silicate with a modulus of 1.

4.

5. A method for preparing alkali-activated lithium mica tailings concrete as described in any one of claims 1-4, characterized in that, The preparation steps include the following: Step 1: Weigh each raw material according to the mixing ratio; Step 2: Dry the lithium mica residue at 105℃ and grind it in a ball mill for 30 minutes for later use; Step 3: Add the coarse aggregate and fine aggregate to the mixing equipment in sequence and mix evenly; Step 4: Add the lithium mica slag, blast furnace slag, and solid alkali activator to the mixing equipment in sequence and mix evenly; Step 5: Add water to the mixing device and mix well; Step 6: Pour the mixture into a mold or spread it out to solidify and shape.

6. The method for preparing alkali-activated lithium mica tailings concrete according to claim 5, characterized in that, The stirring time for step three is 90 seconds; the stirring time for step four is 90 seconds; and the stirring time for step five is 3 minutes.

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