A non-fired lightweight aggregate with high lithium slag content and a method for its co-preparation using lepidolite slag and spodumene slag.

Abstract

This invention provides a high-lithium slag-content non-fired lightweight aggregate and a method for its synergistic preparation using lepidolite slag and spodumene slag. The raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate include lithium slag material and functional additives; the lithium slag material includes lepidolite slag and spodumene slag; the functional additives include binders, activators, and mineralizers. This invention, through the synergistic use of lepidolite slag and spodumene slag, increases the dry-basis lithium slag content in the non-fired lightweight aggregate to over 80%, reduces the cement content to below 15%, eliminates the need for the introduction of active components such as fly ash, results in low cement content and short curing time, and achieves high-content resource utilization of lithium slag. Furthermore, the non-fired lightweight aggregate exhibits high compressive strength, low water absorption, and low bulk density, while the combination with mineralizers effectively achieves efficient solidification of beryllium. Its excellent comprehensive performance makes it widely applicable in the construction industry and other fields.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization and environmental protection materials technology, and relates to a non-fired lightweight aggregate with high lithium slag content, specifically to a non-fired lightweight aggregate with high lithium slag content and a method for preparing it by synergistic use of lepidolite slag and spodumene slag. Background Technology

[0002] With the rapid development of the lithium battery industry, a large amount of lithium slag is generated during lithium mining and lithium battery production. Lithium mica slag (containing 0.1~0.5% beryllium) and spodumene slag are the main hazardous solid wastes in the lithium battery industry. Traditional disposal methods (landfill or high-temperature sintering) have problems such as excessive beryllium leaching (>0.02mg / L) and high energy consumption (sintering temperature >1100℃). Moreover, lithium slag contains a large amount of silicon, aluminum, calcium and other elements, and landfilling will cause a large amount of resource waste. Therefore, how to harmlessly and recycle lithium slag is of great significance to the healthy development of the lithium battery industry.

[0003] Artificial lightweight aggregates possess advantages such as lightweight, high strength, and excellent thermal insulation properties, and are commonly used in building materials, thermal insulation materials, landscaping and environmental protection industries, and sanitary backfilling. CN 117185690A discloses a lithium slag-based non-fired lightweight ceramsite, its preparation method, and its applications. The raw materials for the non-fired lightweight ceramsite, by weight, include: 60-80 parts of spodumene-derived lithium slag, 10-20 parts of cement, 8-15 parts of quicklime, 3-8 parts of alkali activator, 1-6 parts of foaming agent, and 12-20 parts of water. However, the amount of lithium slag is relatively small, and due to the insufficient activity of spodumene slag, a large amount of quicklime and cement must be added to prepare high-strength non-fired lightweight aggregates. CN 118878232A discloses a modified lepidolite slag artificial lightweight aggregate and its preparation method. The raw materials of the modified lepidolite slag artificial lightweight aggregate include 30-60% lithium slag, 15-20% finely ground lithium slag, 10-20% siliceous materials, 8-10% binder, and also include 0-0.2% of an activator by mass of the binder, 3-5% of water by mass of the raw materials, and 5-10% of a modifier by mass of the raw materials. This patent proposes a method for treating lepidolite slag; however, due to the insufficient volcanic ash content in the lepidolite slag, additional siliceous materials need to be introduced, thus increasing production costs. Furthermore, the use of a single cement curing method relies on physical encapsulation for beryllium fixation, which, during long-term use, can lead to a rebound in beryllium leaching concentration due to CSH gel carbonization or acid rain erosion, posing a significant risk of exceeding standards.

[0004] To address the issues of insufficient disposal of lithium mica slag and spodumene slag, limited beryllium solidification methods, easy rebound of beryllium leaching concentration, and increased costs due to the need for additional silicon sources, it is necessary to provide a new type of non-fired lightweight aggregate. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a non-fired lightweight aggregate with high lithium slag content and a method for its co-preparation using lepidolite slag and spodumene slag. This invention, through the synergistic use of lepidolite slag, spodumene slag, and mineralizers, solves problems in existing technologies such as insufficient disposal capacity of lepidolite slag and spodumene slag, a single beryllium solidification method, easy rebound of beryllium leaching concentration, and the need for additional silicon sources, which increases costs.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a non-fired lightweight aggregate with high lithium slag content, wherein the raw materials for preparing the non-fired lightweight aggregate with high lithium slag content include: lithium slag material and functional additives.

[0008] The lithium slag material includes lepidolite slag and spodumene slag; the functional additives include binders, activators and mineralizers.

[0009] This invention, by synergistically utilizing lepidolite slag and spodumene slag, can maximize the promotion of crystallization and bonding reactions, reduce the amount of cement and other pozzolanic active materials (mineral powder, fly ash, etc.) added, and generate more ettringite, CSH, and CASH, thereby further improving the compressive strength of the non-fired lightweight aggregate. Furthermore, by using the complementary lithium slag blending of lepidolite slag and spodumene slag, this invention can achieve a high lithium content of >80% (dry basis total content) in the non-fired lightweight aggregate, thereby reducing the usage of cement, mineral powder, and fly ash, and thus realizing the resource utilization of high lithium slag content, reducing costs.

[0010] In addition, the deep mineralization and solidification of harmful elements such as beryllium are achieved through the synergistic effect of lattice fixation and physical barrier of the silicon-aluminum network structure; this results in non-fired lightweight aggregates with advantages such as high compressive strength, low water absorption, low bulk density, and safety and stability. Its comprehensive performance is excellent and it can be widely used in the construction industry and other fields.

[0011] As a preferred technical solution of the present invention, the raw materials for preparing the high lithium slag content non-fired lightweight aggregate, by mass fraction, include: 30-70 wt% lithium mica slag, 10-50 wt% spodumene slag, 5-15 wt% binder, 1-5 wt% activator and 0-3 wt% mineralizer.

[0012] For example, the content of lithium mica slag in the raw materials for preparing the high lithium slag content non-fired lightweight aggregate is 30~70wt%, for example, it can be 30wt%, 40wt%, 50wt%, 60wt% or 70wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] The content of spodumene slag in the raw materials for preparing the high lithium slag non-fired lightweight aggregate is 10~50wt%, for example, it can be 10wt%, 20wt%, 30wt%, 40wt% or 50wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] The binder content in the raw materials for preparing the high lithium slag content non-burning lightweight aggregate is 5~15wt%, for example, it can be 5wt%, 8wt%, 11wt% or 15wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] The content of activator in the raw materials for preparing the high lithium slag content non-burning lightweight aggregate is 1~5wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt% or 5wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] The content of mineralizer in the raw materials for preparing the high lithium slag non-fired lightweight aggregate is 0~3wt%, for example, it can be 0wt%, 0.5wt%, 1wt%, 2wt% or 3wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] It is worth noting that when the leaching toxicity concentration of the lithium mica residue itself is extremely low, no mineralizer needs to be added, thus achieving resource conservation.

[0018] As a preferred embodiment of the present invention, the water content of the lithium mica residue is 15-30%, for example, it can be 15%, 20%, 25% or 30%, etc., but is not limited to the listed values, and the values ​​within the range are also applicable.

[0019] Preferably, the moisture content of the spodumene slag is 15-30%, for example, it can be 15%, 20%, 25% or 30%, but it is not limited to the listed values. Values ​​within the range are also applicable.

[0020] Preferably, the water content in the raw materials for preparing the high lithium slag content non-fired lightweight aggregate is 25~30wt%, for example, it can be 25wt%, 26wt%, 27wt%, 28wt%, 29wt% or 30wt%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the total content of lepidolite slag and spodumene slag in the raw materials for preparing the high lithium slag content non-fired lightweight aggregate is not less than 80 wt%, for example, it can be 80 wt%, 82 wt%, 84 wt%, 86 wt% or 88 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0022] Preferably, by mass fraction, the lithium mica slag includes: 22-26% SiO2, 15-19% Al2O3, 18-22% SO3, 18-19% CaO, 9-10% Na2O+ K2O, and other unavoidable impurities.

[0023] For example, the SiO2 content in the lithium mica slag is 22-26%, such as 22%, 23%, 24%, 25% or 26%, etc., but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] The Al2O3 content in the lithium mica slag is 15-19%, for example, it can be 15%, 16%, 17%, 18% or 19%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] The SO3 content in the lithium mica residue is 18-22%, for example, it can be 18%, 19%, 20%, 21% or 22%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] The CaO content in the lithium mica slag is 18-19%, for example, it can be 18%, 18.2%, 18.4%, 18.6%, 18.8% or 19%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The Na2O+ K2O content in the lithium mica slag is 9~10%, for example, it can be 9%, 9.2%, 9.4%, 9.6%, 9.8% or 10%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] The unavoidable impurities in the lithium mica residue include components such as manganese, rubidium, cesium, and fluorine.

[0029] Preferably, by mass fraction, the spodumene slag comprises: 42-48% SiO2, 20-23% Al2O3, 12-16% SO3, 11.5-15.5% CaO, 0.3-0.8% Na2O+K2O, and other unavoidable impurities.

[0030] For example, the SiO2 content in the spodumene slag is 42-48%, such as 42%, 44%, 45%, 46%, 47% or 48%, etc., but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] The Al2O3 content in the spodumene slag is 20-23%, for example, it can be 20%, 21%, 22% or 23%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The SO3 content in the spodumene slag is 12-16%, for example, it can be 12%, 13%, 14%, 15% or 16%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] The CaO content in the spodumene slag is 11.5% to 15.5%, for example, it can be 11.5%, 12.5%, 13.5%, 14.5% or 15.5%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] The Na2O+ K2O content in the spodumene slag is 0.3~0.8%, for example, it can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] It is worth noting that the unavoidable impurities in the spodumene slag include components such as manganese, rubidium, cesium, and fluorine.

[0036] As a preferred embodiment of the present invention, the activator includes any one or a combination of at least two of calcium hydroxide, calcium oxide, calcium sulfate dihydrate, or carbide slag. Typical but non-limiting combinations include: a combination of calcium hydroxide and calcium oxide, a combination of calcium hydroxide, calcium oxide, and calcium sulfate dihydrate, a combination of calcium sulfate dihydrate and carbide slag, or a combination of calcium hydroxide, calcium oxide, calcium sulfate dihydrate, and carbide slag.

[0037] The activator described in this invention can provide an alkaline environment for the system, so that the aluminosilicates in lepidolite slag and spodumene slag dissolve and release silicate and aluminate ions under alkaline conditions, which recombine to form a three-dimensional network structure of CAH and CASH.

[0038] Preferably, the mineralizing agent comprises calcium dihydrogen phosphate and / or calcium hydrogen phosphate.

[0039] Preferably, the adhesive comprises cement.

[0040] The cement is ordinary commercially available 425 silicate cement.

[0041] In this invention, phosphate (mineralizing agent) can be used to further mineralize beryllium in lithium mica slag (phosphate mineralization is added for lightweight aggregates with high leaching toxicity); if the amount added is too low, the mineralization effect of harmful elements will be low, and if the amount added is too high, the strength of the resulting non-fired lightweight aggregate will decrease.

[0042] It is worth noting that the synergistic effect of lepidolite slag and spodumene slag provided by this invention reduces the bulk density and water absorption rate of non-fired lightweight aggregates, and increases the compressive strength of the cylinder. In addition, chemical solidification achieves efficient solidification of beryllium in lepidolite slag, reducing the leaching rate of beryllium.

[0043] Specifically, the bulk density of the non-fired lightweight aggregate is 600~1100 kg / m³. 3 For example, it could be 600 kg / m 3 700kg / m 3 800kg / m 3 900kg / m 3 1000kg / m 3 Or 1100kg / m 3 This applies to, but is not limited to, the listed values; other unlisted values ​​within the range are also applicable.

[0044] Preferably, the water absorption rate of the non-fired lightweight aggregate in 1 hour is not higher than 15%, for example, it can be 14%, 13%, 10%, 9% or 8%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the compressive strength of the non-fired lightweight aggregate is 5~10.51MPa, for example, it can be 5MPa, 8MPa, 9MPa, 10MPa or 10.51MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] Preferably, the beryllium concentration of the non-fired lightweight aggregate after toxic leaching is <0.01 mg / L, for example, it can be 0.009 mg / L, 0.0065 mg / L, 0.005 mg / L, 0.004 mg / L or 0.002 mg / L, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] Secondly, the present invention provides a method for preparing non-burning lightweight aggregate with high lithium slag content as provided in the first aspect, the preparation method comprising the following steps:

[0048] (1) Mix lithium mica slag, spodumene slag and activator, and ball mill to obtain composite slag material;

[0049] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir and then granulate to obtain raw material balls;

[0050] (3) Steam curing is performed on the raw material balls obtained in step (2) to obtain the non-fired lightweight aggregate with high lithium slag content.

[0051] As a preferred technical solution of the present invention, the rotation speed of the ball mill in step (1) is 1200~1800 r / min, for example, it can be 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1600 r / min, 1700 r / min or 1800 r / min, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] Preferably, the ball milling time in step (1) is 30 to 90 minutes, for example, it can be 30 minutes, 40 minutes, 50 minutes, 70 minutes or 90 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, the average particle size of the composite slag material in step (1) is >80 mesh, for example, it can be 85 mesh, 90 mesh, 95 mesh, 100 mesh or 110 mesh, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] Preferably, the stirring time in step (2) is 20 to 40 minutes, for example, it can be 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] As a preferred technical solution of the present invention, the granulation process in step (2) includes disc granulation or roller pressing granulation.

[0056] Preferably, the rotational speed in the disc granulation is 20~30 r / min, for example, it can be 20 r / min, 22 r / min, 24 r / min, 26 r / min, 28 r / min or 30 r / min, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0057] It is worth noting that water mist is sprayed evenly during the disc granulation process to achieve uniform granulation.

[0058] Preferably, the loading pressure in the roller pressing granulation is 1~5kN, for example, it can be 1kN, 2kN, 3kN, 4kN or 5kN, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0059] Preferably, the rotational speed in the roller granulation is 100~200 r / min, for example, it can be 100 r / min, 120 r / min, 140 r / min, 160 r / min, 180 r / min or 200 r / min, etc., but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0060] It is worth noting that in the granulation process described in step (2) of the present invention, when the moisture content in the raw material is low, disc granulation is used, and water is sprayed evenly during the disc granulation process to control the moisture content in the raw material pellets; when the moisture content in the raw material is appropriate, roller pressing granulation is used.

[0061] As a preferred technical solution of the present invention, the average particle size of the raw material balls in step (2) is 5~30mm, for example, it can be 5mm, 10mm, 15mm, 20mm, 25mm or 30mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0062] Preferably, the moisture content of the raw material balls in step (2) is 25-30%, for example, it can be 25%, 26%, 27%, 28%, 29% or 30%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0063] It is worth noting that the moisture content of the raw material balls described in this invention is 25-30%. If the moisture content is too low, the raw material will be loose and unable to be granulated, resulting in poor hydration in the later stages. Conversely, if the moisture content is too high, the raw material will become a paste and cannot be shaped.

[0064] As a preferred technical solution of the present invention, the temperature of steam curing in step (3) is 40~110℃, for example, it can be 40℃, 60℃, 80℃, 100℃ or 110℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0065] Preferably, the steam curing time in step (3) is 4 to 12 hours, for example, it can be 4 hours, 6 hours, 8 hours, 10 hours or 12 hours, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0066] Preferably, the humidity of the steam curing in step (3) is 90~99%, for example, it can be 90%, 92%, 94%, 96%, 98% or 99%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] In this invention, steam curing accelerates the hydration and crystallization bonding reaction between the binder (cement) and lithium slag. However, excessively high temperatures during the steam curing process can lead to excessively rapid hydration and crystallization bonding, causing the lightweight aggregate to expand and crack. Conversely, excessively low temperatures can lead to excessively slow hydration and crystallization bonding.

[0068] As a preferred embodiment of the present invention, the method for preparing non-fired lightweight aggregate with high lithium slag content provided in the first aspect by synergistically using lithium mica slag and spodumene slag, as provided in the second aspect of the present invention, includes the following steps:

[0069] (1) Mix lepidolite slag, spodumene slag and activator, and ball mill at 1200~1800 r / min for 30~90 min to obtain composite slag with an average particle size >80 mesh;

[0070] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir for 20-40 minutes and then granulate to obtain raw material balls with an average particle size of 5-30 mm;

[0071] The granulation process includes disc granulation or roller pressing granulation;

[0072] (3) The raw material balls obtained in step (2) are steam-cured for 4 to 12 hours at a temperature of 40 to 110°C and a humidity of 90 to 99% to obtain the non-fired lightweight aggregate with high lithium slag content.

[0073] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] (1) By synergistically utilizing lithium mica slag and spodumene slag, this invention significantly increases the amount of lithium slag used and reduces the use of other raw materials such as silicon sources, thereby reducing production costs and achieving the goal of cost reduction and efficiency improvement.

[0076] (2) This invention achieves chemical solidification of beryllium in lithium mica slag by using mineralizing agents, which has a better solidification effect than the single physical solidification of cement.

[0077] (3) The present invention utilizes the synergistic effect of lithium mica slag and spodumene slag in terms of composition, so that the resulting non-fired lightweight aggregate has advantages such as strong compressive strength, low water absorption and bulk density. Its comprehensive performance is excellent and it can be widely used in the construction industry and other fields. Detailed Implementation

[0078] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0079] The chemical composition of spodumene slag and lepidolite slag used in the following examples and comparative examples is shown in Table 1:

[0080] Table 1

[0081]

[0082] The beryllium content of the lithium mica residue, after being leached by sulfuric acid and nitric acid toxicity method, was found to be 3.68 mg / L by ICP-MS analysis.

[0083] Example 1

[0084] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The raw materials for preparing the non-fired lightweight aggregate with high lithium slag content include: 50wt% lithium mica slag, 35wt% spodumene slag, 8wt% binder, 5wt% activator, and 2wt% mineralizer, by mass fraction.

[0085] The water content of the lithium mica slag is 20%, the water content of the spodumene slag is 20%, and the water content in the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate is 28 wt%.

[0086] The activator is calcium oxide; the mineralizing agent is dicalcium phosphate; and the binder is cement.

[0087] The method for preparing the high-lithium slag-content non-fired lightweight aggregate described in this embodiment using lepidolite slag and spodumene slag synergistically includes the following steps:

[0088] (1) Mix lithium mica slag, spodumene slag and activator, and ball mill at 1500 r / min for 30-90 min to obtain composite slag with an average particle size of 150 mesh;

[0089] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir for 30 minutes and then granulate to obtain raw material balls with an average particle size of 20 mm and a moisture content of 28%.

[0090] The granulation process includes disc granulation; during the disc granulation process, water mist is sprayed evenly, the rotation speed is 25 r / min, and the tilt angle is set to 60°.

[0091] (3) The raw material balls obtained in step (2) are steam-cured for 10 hours at a temperature of 80℃ and a humidity of 96% to obtain the non-fired lightweight aggregate with high lithium slag content.

[0092] Example 2

[0093] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The raw materials for preparing the non-fired lightweight aggregate with high lithium slag content include: 70wt% lithium mica slag, 10wt% spodumene slag, 15wt% binder, 4wt% activator, and 1wt% mineralizer, by mass fraction.

[0094] The water content of the lithium mica slag is 30%, the water content of the spodumene slag is 15%, and the water content of the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate is 25 wt%.

[0095] The activator is calcium hydroxide; the mineralizing agent is calcium dihydrogen phosphate; and the binder is cement.

[0096] The method for preparing the high-lithium slag-content non-fired lightweight aggregate described in this embodiment using lepidolite slag and spodumene slag synergistically includes the following steps:

[0097] (1) Mixed lithium mica slag, spodumene slag and activator, ball milled at 1200 r / min for 90 min to obtain composite slag with an average particle size of 100 mesh;

[0098] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir for 40 minutes and then granulate to obtain raw material balls with an average particle size of 10 mm and a moisture content of 25%.

[0099] The granulation process is roller pressing granulation; the loading pressure in the roller pressing granulation is 3kN, and the rotation speed is 150r / min;

[0100] (3) The raw material balls obtained in step (2) are steam-cured for 12 hours at a temperature of 40℃ and a humidity of 90% to obtain the non-fired lightweight aggregate with high lithium slag content.

[0101] Example 3

[0102] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The raw materials for preparing the non-fired lightweight aggregate with high lithium slag content include: 60wt% lithium mica slag, 25wt% spodumene slag, 11wt% binder, 1wt% activator, and 3wt% mineralizer, by mass fraction.

[0103] The water content of the lithium mica slag is 15%, the water content of the spodumene slag is 30%, and the water content of the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate is 30 wt%.

[0104] The activator includes any one or a combination of at least two of calcium hydroxide, calcium oxide, calcium sulfate dihydrate, or carbide slag; the mineralizer includes calcium dihydrogen phosphate and calcium hydrogen phosphate in a mass ratio of 1:1; and the binder includes cement.

[0105] The method for preparing the high-lithium slag-content non-fired lightweight aggregate described in this embodiment using lepidolite slag and spodumene slag synergistically includes the following steps:

[0106] (1) Mixed lithium mica slag, spodumene slag and activator, ball milled at 1800 r / min for 30 min to obtain composite slag with an average particle size of 170 mesh;

[0107] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir for 20 minutes and then granulate to obtain raw material balls with an average particle size of 30 mm;

[0108] The granulation process includes disc granulation or roller pressing granulation;

[0109] (3) The raw material balls obtained in step (2) are steam-cured for 4 hours at a temperature of 110℃ and a humidity of 90% to obtain the non-fired lightweight aggregate with high lithium slag content.

[0110] Example 4

[0111] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and that of Embodiment 1 is:

[0112] In this embodiment, the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate are adjusted to: 30wt% lithium mica slag, 50wt% spodumene slag, 14wt% binder, 4wt% activator, and 2wt% mineralizer.

[0113] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment is the same as that in Embodiment 1.

[0114] Example 5

[0115] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and that of Embodiment 1 is:

[0116] In this embodiment, the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate are adjusted to: 20wt% lithium mica slag, 65wt% spodumene slag, 8wt% binder, 5wt% activator, and 2wt% mineralizer.

[0117] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment is the same as that in Embodiment 1.

[0118] Example 6

[0119] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and that of Embodiment 1 is:

[0120] In this embodiment, the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate are adjusted to: 80wt% lithium mica slag, 5wt% spodumene slag, 8wt% binder, 5wt% activator, and 2wt% mineralizer.

[0121] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment is the same as that in Embodiment 1.

[0122] Example 7

[0123] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and that of Embodiment 1 is:

[0124] In this embodiment, the content of the mineralizer is adjusted to 4 wt%, and the content of the binder is adjusted to 6 wt%.

[0125] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment is the same as that in Embodiment 1.

[0126] Example 8

[0127] This embodiment provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and that of Embodiment 1 is:

[0128] In this embodiment, the content of the mineralizer is adjusted to 0.1 wt%, and the content of the binder is adjusted to 9.9 wt%.

[0129] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment is the same as that in Embodiment 1.

[0130] Example 9

[0131] This embodiment provides a non-burning lightweight aggregate with high lithium slag content, and the raw materials for preparing the non-burning lightweight aggregate are the same as those in Embodiment 1.

[0132] The difference between the preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment and that in Example 1 is only:

[0133] In this embodiment, the moisture content of the raw material balls in step (2) is adjusted to 10%.

[0134] Example 10

[0135] This embodiment provides a non-burning lightweight aggregate with high lithium slag content, and the raw materials for preparing the non-burning lightweight aggregate are the same as those in Embodiment 1.

[0136] The difference between the preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment and that in Example 1 is only:

[0137] In this embodiment, the moisture content of the raw material balls in step (2) is adjusted to 40%.

[0138] Example 11

[0139] This embodiment provides a non-burning lightweight aggregate with high lithium slag content, and the raw materials for preparing the non-burning lightweight aggregate are the same as those in Embodiment 1.

[0140] The difference between the preparation method of the non-fired lightweight aggregate with high lithium slag content described in this embodiment and that in Example 1 is only:

[0141] In this embodiment, the humidity of the steam curing in step (3) is adjusted to 85%.

[0142] Comparative Example 1

[0143] This comparative example provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and Example 1 is that:

[0144] In this comparative example, the spodumene slag is replaced with an equal amount of lepidolite slag, that is, the spodumene slag in the non-fired lightweight aggregate is omitted.

[0145] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this comparative example is the same as that in Example 1.

[0146] Comparative Example 2

[0147] This comparative example provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and Example 1 is that:

[0148] In this comparative example, the lepidolite slag is replaced with an equal amount of spodumene slag, that is, the lepidolite slag in the non-fired lightweight aggregate is omitted.

[0149] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this comparative example is the same as that in Example 1.

[0150] Comparative Example 3

[0151] This comparative example provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and Example 1 is that:

[0152] In this comparative example, the mineralizer is adjusted to an equal amount of binder, thus omitting the use of the mineralizer.

[0153] The preparation method of the non-fired lightweight aggregate with high lithium slag content described in this comparative example is the same as that in Example 1.

[0154] Comparative Example 4

[0155] This comparative example provides a non-fired lightweight aggregate with high lithium slag content. The only difference between this non-fired lightweight aggregate and Example 1 is that:

[0156] In this comparative example, the spodumene slag is replaced with an equal amount of fly ash.

[0157] Performance testing:

[0158] (1) The bulk density, 1-hour water absorption rate and cylinder compressive strength of the non-fired lightweight aggregates with high lithium slag content provided in the above embodiments and comparative examples were tested, and the results are shown in Table 2.

[0159] (2) The non-burning lightweight aggregates with high lithium slag content provided in the above embodiments and comparative examples were subjected to sulfuric acid and nitric acid leaching, and the beryllium content was detected by ICP-MS. The leaching results are shown in Table 2.

[0160] Table 2

[0161]

[0162] According to Table 2, the following points can be observed:

[0163] (1) Comprehensive analysis of Examples 1-3 shows that the present invention, by synergistically combining lithium mica slag and spodumene slag, utilizes mineralizers to improve the compressive strength of non-fired light aggregate, reduce water absorption and bulk density, and effectively solidify beryllium elements, which can be widely applied in the construction industry and other fields.

[0164] (2) Comprehensive analysis of Examples 1, 4-6 and Comparative Examples 1-2 shows that the present invention can control the bulk density and cylinder compressive strength of the non-fired lightweight aggregate by adjusting the ratio of lithium mica slag and spodumene slag.

[0165] When the amount of lithium mica residue is too low or too high, it will lead to a decrease in cylinder compressive strength.

[0166] When the use of the lepidolite slag is omitted, the insufficient supply of volcanic ash activity will result in a reduction in the generated CAH and CASH three-dimensional network structure, leading to a decrease in cylinder compressive strength. When the use of the spodumene slag is omitted, the insufficient supply of silicon and aluminum will result in a reduction in the generated CAH and CASH three-dimensional network structure, leading to a decrease in cylinder compressive strength.

[0167] (3) When comprehensively analyzing Examples 1, 7-8 and Comparative Example 3, the mineralizer is one of the important factors affecting the solidification effect of beryllium. Specifically, chemical precipitation is used to make the beryllium react with phosphate and enter the hydroxyapatite lattice. Then, physical encapsulation with cement is used to achieve double solidification.

[0168] When the amount of the mineralizer used is too low, or even when no mineralizer is used, the curing effect will be poor due to insufficient physical curing effect.

[0169] (4) Comprehensive analysis of Examples 1 and 9-10 shows that if the moisture content of the raw material balls is too low or too high, the cylinder compressive strength will decrease.

[0170] (5) Comprehensive analysis of Examples 1 and 11 shows that the low humidity during the steam curing process will lead to insufficient water in the hydration reaction, thereby affecting the generation of hydration products and resulting in a decrease in cylinder pressure strength.

[0171] (6) Comprehensive analysis of Example 1 and Comparative Example 4 shows that although the physical properties of lightweight aggregates with more lithium slag replaced by fly ash do not change significantly, the cost of using fly ash as raw material is high, and it is impossible to achieve the purpose of reducing costs and increasing efficiency and treating lithium slag solid waste.

[0172] In summary, this invention improves the compressive strength of non-fired lightweight aggregates, reduces water absorption and bulk density by synergistically combining lepidolite slag and spodumene slag, and effectively solidifies beryllium elements by combining mineralizers. Its comprehensive performance is excellent and it can be widely used in the construction industry and other fields.

[0173] The applicant declares that the specific embodiments described above further illustrate the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-fired lightweight aggregate with high lithium slag content, characterized in that, The raw materials for preparing the high lithium slag content non-fired lightweight aggregate include: lithium slag and functional additives. The lithium slag material includes lepidolite slag and spodumene slag; the functional additives include binders, activators and mineralizers. The total content of lepidolite slag and spodumene slag in the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate shall not be less than 80 wt%. The mineralizing agent includes calcium dihydrogen phosphate and / or calcium hydrogen phosphate; The raw materials for preparing the high lithium slag content non-fired lightweight aggregate, by mass fraction, include: 30-70 wt% lepidolite slag, 10-50 wt% spodumene slag, 5-15 wt% binder, 1-5 wt% activator, and 0.5-3 wt% mineralizer.

2. The non-fired lightweight aggregate with high lithium slag content according to claim 1, characterized in that, The water content of the lithium mica residue is 15-30%; The spodumene slag has a moisture content of 15-30%; The water content in the raw materials for preparing the high-lithium slag-content non-fired lightweight aggregate is 25-30 wt%.

3. The non-fired lightweight aggregate with high lithium slag content according to claim 1, characterized in that, The activator includes any one or a combination of at least two of calcium hydroxide, calcium oxide, calcium sulfate dihydrate, or carbide slag. The adhesive includes cement.

4. The non-fired lightweight aggregate with high lithium slag content according to claim 3, characterized in that, The bulk density of the non-fired lightweight aggregate is 600~1100 kg / m³. 3 ; The water absorption rate of the non-fired lightweight aggregate is no higher than 15% in 1 hour; The compressive strength of the non-fired lightweight aggregate is 5~10.51MPa; The beryllium concentration of the non-fired lightweight aggregate after toxic leaching is <0.01 mg / L.

5. A method for preparing high-lithium slag-content non-fired lightweight aggregate according to any one of claims 1 to 4 using lepidolite slag and spodumene slag synergistically, characterized in that, The method includes the following steps: (1) Mix lithium mica slag, spodumene slag and activator, and ball mill to obtain composite slag material; (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir and then granulate to obtain raw material balls; (3) Steam curing is performed on the raw material balls obtained in step (2) to obtain the non-fired lightweight aggregate with high lithium slag content.

6. The method according to claim 5, characterized in that, The rotational speed of the ball mill in step (1) is 1200~1800 r / min; The ball milling time in step (1) is 30~90 min; The average particle size of the composite slag material in step (1) is >80 mesh; The stirring time in step (2) is 20~40 minutes.

7. The method according to claim 5, characterized in that, The granulation process in step (2) includes disc granulation or roller pressing granulation; The rotational speed in the disc granulation process is 20~30 r / min; The loading pressure in the roller pressing granulation is 1~5kN; The rotational speed in the roller pressing granulation is 100~200 r / min; The average particle size of the raw material balls in step (2) is 5~30mm; The moisture content of the raw material balls in step (2) is 25-30%.

8. The method according to claim 5, characterized in that, The steam curing temperature in step (3) is 40~110℃; The steam curing time in step (3) is 4~12 hours; The humidity for steam curing in step (3) is 90-99%.

9. The method according to claim 5, characterized in that, The method includes the following steps: (1) Mix lepidolite slag, spodumene slag and activator, and ball mill at 1200~1800 r / min for 30~90 min to obtain composite slag with an average particle size of >80 mesh; (2) Mix cement, mineralizer and the mixed slag obtained in step (1), stir for 20-40 minutes and then granulate to obtain raw material balls with an average particle size of 5-30 mm; The granulation process includes disc granulation or roller pressing granulation; (3) The raw material balls obtained in step (2) are steam-cured for 4 to 12 hours at a temperature of 40 to 110°C and a humidity of 90 to 99% to obtain the non-fired lightweight aggregate with high lithium slag content.

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