Lithium slag-based unfired lightweight aggregate and preparation method thereof

Abstract

The embodiment of the invention provides a lithium slag-based unfired lightweight aggregate and a preparation method thereof. The raw materials of the lithium slag-based unfired lightweight aggregate comprise a raw material and water, and the raw material comprises the following components in percentage by mass: 25-60% of lepidolite slag, 10-50% of solid waste and 5-40% of cement; the lepidolite slag comprises aluminosilicate and harmful elements such as fluorine, beryllium and thallium; the solid waste comprises the following components in percentage by mass: 10-70% of silicon dioxide, 2-30% of aluminum oxide and 10-60% of calcium oxide. Harmful elements in the lithium slag-based unfired lightweight aggregate are stably cured, the cylinder compressive strength is relatively high, the water absorption rate is relatively low, and the density is adjustable. The preparation cost is low, the production process is simple, large-scale production is easy, and the material can be applied to the fields of roadbed materials, building materials and the like.

Description

Technical Field

[0001] The present application relates to the field of new materials, and in particular to a lithium slag-based unfired lightweight aggregate and a preparation method thereof. Background Art

[0002] With the rapid development of new energy vehicles, the demand for lithium carbonate has grown rapidly. Lithium carbonate is mainly extracted from lithium ores such as spodumene and lepidolite. When lithium salt products are extracted from lepidolite, spodumene and other lithium ores, lithium slag will be produced; taking lepidolite slag as an example, it is not only difficult to dispose of, but also contains harmful components such as fluorine, beryllium, and thallium, which can easily cause major pollution accidents after leaching.

[0003] Although there is a method of using lithium slag as raw material to prepare lightweight aggregate, the solidification effect of harmful components such as fluorine, beryllium, and thallium in lithium slag (especially lithium mica slag) is not taken into account during the preparation process. In addition, the prepared lightweight aggregate has the disadvantages of high water absorption, large amount of cement, and small amount of lithium mica slag processed. Summary of the invention

[0004] The present application provides a lithium slag-based unburned light aggregate and a preparation method thereof. The harmful elements in the lithium slag-based unburned light aggregate of the present application are stably solidified, the cylinder pressure strength is high, the water absorption rate is low, and the density is adjustable. The preparation cost is low, the production process is simple, and it is easy to mass produce, and it can be applied to roadbed materials, building materials and other fields.

[0005] In the first aspect, the present application provides a lithium slag-based unburned lightweight aggregate, whose raw materials include raw materials and water. The raw materials include 25%~60% of lithium mica slag, 10%~50% of solid waste and 5%~40% of cement by mass fraction; the lithium mica slag includes aluminum silicate, fluorine, beryllium and thallium; the components of the solid waste include 10%~70% silicon dioxide, 2%~30% aluminum oxide, and 10%~60% calcium oxide by mass fraction.

[0006] Based on the lithium slag-based non-burning light aggregate of the present application, the inventor found that when the lithium mica slag and solid waste are mixed, it has good volcanic ash activity, and the lithium mica slag with volcanic ash active components and solid waste and cement are solidified, and the harmful components of fluorine, beryllium and thallium in the lithium mica slag will also be fixed; in addition, since the solid waste also contains a large amount of aluminum oxide, silicon oxide, calcium oxide, etc., calcium hydroxide is formed during the reaction process, and the heat release accelerates the hydration reaction. The solid waste and the lithium mica slag are hydrated to form gel-like hydrated calcium silicate and hydrated aluminum calcium silicate gel, thereby filling the gaps generated after the cement solidifies, so that the porosity of the lithium slag-based non-burning light aggregate can not only be reduced, but also ensure that the lithium slag-based non-burning light aggregate has a lower water absorption rate and good cylinder pressure strength and a lower bulk density, and the harmful components of fluorine, beryllium and thallium in the lithium mica slag can be further fixed, greatly reducing the probability of leaching of harmful components. In addition, the cement dosage of the present application is small, which can reduce the preparation cost of the lithium slag-based non-burning light aggregate.

[0007] In one possible implementation, the mass content of silicon dioxide in the components of the solid waste is 50% to 70%; and / or, based on the mass of the lithium mica slag, the content of fluorine is not more than 5%, the content of beryllium is not more than 1000 ppm, and the content of thallium is not more than 1000 ppm.

[0008] In the above technical scheme, the mass content of silicon dioxide in the solid waste is within the above range, which is more conducive to improving the cylinder compressive strength of lithium slag-based unburned lightweight aggregate; when the content of various harmful elements in the lithium mica slag is within the above range, the harmful substances are stably solidified and the toxic leaching concentration meets the national standard requirements.

[0009] In a possible implementation, the mass content of the lithium mica slag in the raw meal is 35% to 60%; and / or the mass content of the cement in the raw meal is 5% to 25%.

[0010] In the above technical solution, the lithium slag-based unfired lightweight aggregate has higher cylinder compressive strength, lower preparation cost, and harmful substances are less likely to leach out.

[0011] In a possible implementation, the mass content of aluminosilicate is 30% to 60% based on the mass of the lithium mica slag.

[0012] In the above technical solution, the lithium slag-based unburned lightweight aggregate has better cylinder compressive strength and better fixation effect on harmful substances.

[0013] In a possible implementation, the raw material components, calculated by mass fraction, further include 0% to 5% of an auxiliary agent, 0% to 5% of an alkaline activator, and 0% to 5% of a foaming agent; the auxiliary agent includes at least one of calcium oxide and calcium sulfate.

[0014] In the above technical scheme, the auxiliary agent can better and more quickly promote the reaction of lithium mica slag and solid waste in the hydration process, the alkaline activator can improve the activity of lithium mica slag faster and better, which is conducive to the rapid preparation of lithium slag-based unfired light aggregate, and the foaming agent can better reduce the packing density of lithium slag-based unfired light aggregate.

[0015] In a possible implementation, the alkaline activator includes at least one of sodium hydroxide, potassium hydroxide or calcium hydroxide.

[0016] In a possible implementation, the foaming agent includes at least one of ammonium bicarbonate, aluminum powder, and hydrogen peroxide.

[0017] In a possible implementation, the average particle size of the lithium slag-based unburned lightweight aggregate is 2 mm to 15 mm.

[0018] In a second aspect, the present application provides a method for preparing a lithium slag-based unfired lightweight aggregate, which comprises the following steps: S100, obtaining raw material, the components of which include 25% to 60% of lithium mica slag, 10 to 50% of solid waste and 5% to 40% of cement; the lithium mica slag includes aluminosilicate, fluorine, beryllium and thallium, and the components of the solid waste, by mass, include 10% to 70% of silicon dioxide, 2% to 30% of aluminum oxide, and 10% to 60% of calcium oxide; S200, mixing water and the raw material for granulation to obtain raw material balls; S300, curing the raw material balls to obtain lithium slag-based unfired lightweight aggregate.

[0019] Based on the preparation method of the present application, lithium slag-based unfired light aggregate with high cylinder pressure strength, adjustable bulk density and low water absorption can be obtained without firing, and it has a good solidification effect on harmful components such as fluorine, beryllium, and thallium in the prepared lithium slag-based unfired light aggregate.

[0020] In a possible implementation, microwaves are used to cure the raw balls.

[0021] In the above technical solution, microwave curing of the raw material balls can make the raw material balls solidify more quickly to form lithium slag-based unfired lightweight aggregate.

[0022] The beneficial effects of this application are as follows: The present application provides a lithium slag-based unfired light aggregate and a preparation method thereof. The raw materials of the lithium slag-based unfired light aggregate include lithium mica slag and other components. The lithium slag-based unfired light aggregate of the present application has a good curing effect on harmful components such as fluorine, beryllium and thallium. Moreover, the lithium slag-based unfired light aggregate of the present application has an adjustable stacking density, a high cylinder pressure strength and a low water absorption rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a process flow chart of the lithium slag-based unburned lightweight aggregate of this application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0025] The lepidolite slag produced in the process of extracting lithium from special lithium ores such as lepidolite / spodumene contains harmful components such as fluorine, beryllium, and thallium, which are easy to leach out and cause major pollution accidents. Although there is currently a method for preparing light aggregate using lithium slag as a raw material, such as CN117185690A, which discloses a method for preparing lithium slag-based unfired light ceramsite, the curing effect of harmful components such as fluorine, beryllium, and thallium in the lepidolite slag is not considered during the preparation process, and the prepared light aggregate has the disadvantages of high water absorption, large cement consumption, and less lithium slag processing.

[0026] In order to improve the above technical problems, the present application provides a lithium slag-based unfired lightweight aggregate and a preparation method thereof. The contents of the present application are described in detail below.

[0027] The raw materials of the lithium slag-based unburned lightweight aggregate in the present application include raw material and water, wherein the raw material, calculated by mass fraction, includes 25%~60% of lithium mica slag, 10%~50% of solid waste and 5%~40% of cement; the lithium mica slag includes aluminosilicate, fluorine, beryllium and thallium, and in the preferred lithium mica slag, the content of harmful substances in its components is as follows: the content of fluorine is not more than 5%, the content of beryllium is not more than 1000ppm, and the content of thallium is not more than 1000ppm; the components of the solid waste, calculated by mass fraction, include 10%~70% silicon dioxide, 2%~30% aluminum oxide, and 10%~60% calcium oxide.

[0028] The inventor found that the mixed solid waste and lithium mica slag have good volcanic ash activity, and the lithium mica slag and solid waste with volcanic ash active components can be solidified with cement, and the harmful components of fluorine, beryllium, and thallium in the lithium mica slag will also be fixed; in addition, since calcium oxide, etc. are also contained in the solid waste, the solid waste can form gel-like hydrated calcium silicate and hydrated calcium aluminum silicate gel with the lithium mica slag through hydration, thereby filling the gaps generated after cement solidification, so that not only the porosity of the lithium slag-based unburned light aggregate can be reduced, and the lithium slag-based unburned light aggregate can be ensured to have lower water absorption and good cylinder pressure strength and lower bulk density, but also the harmful components of fluorine, beryllium, and thallium in the lithium mica slag can be further fixed, greatly reducing the probability of leaching of harmful components. In addition, the cement dosage of the present application is small, which can reduce the preparation cost of the lithium slag-based unburned light aggregate.

[0029] In some embodiments of the present application, in order to improve the cylinder pressure strength of the prepared lithium slag-based unburned light aggregate and make the harmful elements in the lithium slag-based unburned light aggregate less likely to leach, the mass content of lithium mica slag in the raw material is preferably 35%~60%, specifically 35%, 45%, 55% or 60%, etc.; the content of cement in the raw material is 5%~25%, specifically 5%, 10%, 15%, 20% or 25%, etc., so that the preparation cost can be reduced while ensuring the cylinder pressure strength; lithium mica slag The mass content of aluminosilicate in the mother slag is generally 50% to 70%, for example, 50%, 55%, 60% or 70%, etc., and the mass content of silicon dioxide in the solid waste is preferably 10% to 30%, for example, 10%, 20% or 30%, etc.; in addition, in some embodiments of the present application, the mass ratio of lithium mica slag and solid waste can generally be controlled within the range of 1:1 to 3:1, so as to ensure that the cylinder compressive strength of the obtained lithium slag-based unburned lightweight aggregate is higher, and it has a good curing effect on harmful components such as fluorine, beryllium, and thallium.

[0030] In addition, it should be noted that the solid waste in this application may be fly ash, and the specific components of fly ash contain 40% to 60% silicon dioxide, 30% to 50% aluminum oxide, 15% to 20% calcium oxide, etc. The types of fly ash (i.e., solid waste) in this application are described in detail later in this article.

[0031] In addition, in the embodiment of the present application, the components of the raw material can also include 0%~5% auxiliary agent, 0%~5% alkaline activator and 0%~5% foaming agent by mass fraction; wherein the auxiliary agent includes at least one of calcium oxide and calcium sulfate. The auxiliary agent can better and more quickly promote the reaction of lithium mica slag and solid waste in the hydration process, the alkaline activator can improve the activity of lithium mica slag faster and better, which is conducive to the rapid preparation of lithium slag-based unburned light aggregate, and the foaming agent can better reduce the bulk density of lithium slag-based unburned light aggregate. Specifically, in the embodiment of the present application, the alkaline activator is a mixture of sodium hydroxide and calcium hydroxide (which can be called a "composite alkaline activator"), and the mass ratio of sodium hydroxide to calcium hydroxide can be 1:1~3:1; preferably 1:1. In addition, in the embodiment of the present application, the foaming agent includes at least one of ammonium bicarbonate, aluminum powder, and hydrogen peroxide; especially hydrogen peroxide, which has a better foaming effect and can better reduce the bulk density of lithium slag-based unburned light aggregate.

[0032] In addition, the average particle size of the lithium slag-based unburned lightweight aggregate in the present application is generally in the range of 2 mm to 15 mm, so it has a wide range of applications, especially in flower bed greening, toilet backfilling and other scenarios.

[0033] In the second aspect, the present application also provides a method for preparing lithium slag-based unburned lightweight aggregate, the process flow chart of which is as follows: Figure 1 As shown, the specific steps include: S100. Obtaining raw materials, the raw materials include 25% to 60% of lithium mica slag, 10% to 50% of solid waste and 5% to 40% of cement; the lithium mica slag includes aluminosilicate, fluorine, beryllium and thallium, and the components of the solid waste include 10% to 70% of silicon dioxide, 2% to 30% of aluminum oxide and 10% to 60% of calcium oxide by mass.

[0034] In this step, solid waste and lithium mica slag have good volcanic ash activity after mixing, and components with volcanic ash activity can be solidified with cement, and harmful components such as fluorine, beryllium, and thallium in the lithium mica slag can also be stably solidified. In addition, in order to further improve the other properties of lithium slag-based non-burned light aggregate, in this step, 0%~5% additives, 0%~5% alkaline activators, and 0%~5% foaming agents can also be adaptively added; wherein the additives can more quickly stimulate volcanic ash activity, which is conducive to a faster reaction. In addition, in this step, in the preferred lithium mica slag, the content of fluorine element is not more than 5%, the content of beryllium element is not more than 1000ppm, and the content of thallium element is not more than 1000ppm.

[0035] In addition, as an example, the sources of the raw materials in this step are as follows: Lepidolite slag: Lepidolite slag from Guoxuan High-tech Co., Ltd., produced by using lepidolite ore to prepare battery-grade lithium carbonate, and all of them have been detoxified. That is, the thallium in the slag used has been treated, and the thallium and beryllium are still in excess. The composition ratio of the constant components of the washed lepidolite slag is shown in Table 1.

[0036] Table 1 The proportion of constant components in the composition of lithium mica slag

[0037] Moreover, before mixing, the present application will first dry the lithium mica residue to constant weight, and then crush and sieve it, which is conducive to the full mixing of the lithium mica residue and other components. As an example, in some embodiments of the present application, the lithium mica residue is first dried at 105°C to constant weight, then crushed using a wall breaker, and then sieved through a 500-mesh sieve.

[0038] Solid waste: Take fly ash as an example. In the embodiment of this application, the fly ash is the most common first-class fly ash on the market, with a mesh size of 3000. All test items comply with the standard GB1596-2005, regardless of the origin.

[0039] Cement: The most common ordinary Portland cement PO42.5 on the market, all test items meet national standards, regardless of origin.

[0040] In addition, in some embodiments of the present application, the components are fully mixed in a ball mill. As an example, in some embodiments of the present application, the ball milling frequency during mixing is 1000 / min, the ball milling time is 10 minutes, and the cycle is repeated four times, the purpose is to fully mix the components, which is conducive to subsequent full reaction.

[0041] S200, mixing water and raw material for granulation to obtain raw material balls.

[0042] This step is generally carried out in a round pot granulator, the speed is usually 30r / min, and the granulation time is usually controlled within 10min~30min; and in some embodiments of the present application, the raw materials are generally added to the round pot granulator in batches, and water is sprayed with a watering can while adding the raw materials. After the raw materials are adhered together and the small mother balls are screened out, the materials are gradually added and water is sprayed until the diameter of the balls reaches the required diameter.

[0043] When this step is carried out, the following reaction generally occurs: under the action of water, the solid waste and the lithium mica slag undergo hydration to form gel-like hydrated calcium silicate and hydrated calcium aluminosilicate gel, thereby filling the gaps generated after the cement solidifies, so that not only the porosity of the lithium slag-based unburned light aggregate can be reduced, ensuring that the lithium slag-based unburned light aggregate has a lower water absorption rate and a higher cylinder pressure strength, but also the harmful components such as fluorine, beryllium, and thallium in the lithium mica slag can be further solidified, greatly reducing the leaching probability of harmful components such as fluorine, beryllium, and thallium. In addition, since the solid waste also contains a large amount of aluminum oxide, silicon oxide, calcium oxide, etc., calcium hydroxide is formed during the reaction, and heat release accelerates the hydration reaction.

[0044] In addition, in some embodiments of the present application, the total mass of the added water is generally 20% to 80% of the mass of the raw material.

[0045] S300, curing the raw material balls to obtain lithium slag-based unburned light aggregate.

[0046] In this step, the curing method can be a conventional method, specifically, after natural curing at 10°C~30°C for 5h~48h, transferring to a steam curing box, steam curing at 80°C~120°C and 80%~99.99% humidity for 5h~80h, lithium slag-based unburned light aggregate can be obtained.

[0047] In addition, microwave or ultrasonic wave can also be used to cure the raw ball in this step, which can reduce the curing time and improve the process efficiency. This is because microwave can promote the early hydration process of the raw ball, thereby shortening the steam curing time. The specific operation steps are as follows: After natural curing at 10℃~30℃ for 1h~3h, microwave curing for 5min~10min, and then transferring to a steam curing box, steam curing at 80℃~120℃ and 80%~99.99% humidity for 6h~24h, lithium slag-based unburned light aggregate can be obtained.

[0048] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0049] Example 1 The present embodiment provides a lithium slag-based unburned light aggregate, and the preparation method thereof comprises the following steps: (1) The lithium mica slag is dried at 105°C to constant weight, and finally crushed by a wall breaking machine, and then sieved through a 500-mesh screen to obtain powder-grade lithium mica slag, and then the powdered lithium mica slag is mixed with solid waste (fly ash in this embodiment), cement, alkaline activator, etc., and ball milled by a ball mill to form a raw material, wherein the mass fraction of each component in the raw material is as follows: 35% lithium mica slag, 25% fly ash, 30% cement, 5% composite alkaline activator (sodium hydroxide and potassium hydroxide in a mass ratio of 1:1), 3% additive (calcium oxide and calcium sulfate in a mass ratio of 1:1) and 2% hydrogen peroxide. The mass content of aluminum silicate in the lithium mica slag is 30%, the content of fluorine is 5%, the content of beryllium is 1000ppm, and the content of thallium is 1000ppm.

[0050] (2) Add the raw material into a round pot granulator, and add water accounting for 30% of the raw material mass. Granulate it for 20 minutes at room temperature and a speed of 30 r / min to obtain raw material balls.

[0051] (3) After natural curing at 20°C for 6 hours, the aggregate is transferred to a steam curing box and steam-cured for 24 hours at a temperature of 105°C and a humidity of 99.99% to obtain lithium slag-based unburned lightweight aggregate.

[0052] Example 2 The present embodiment provides a lithium slag-based unburned light aggregate, and the preparation method thereof comprises the following steps: (1) The lithium mica slag is dried at 105°C to constant weight, and finally crushed by a wall breaker, and then sieved through a 500-mesh screen to obtain powder-grade lithium mica slag. The powdered lithium mica slag is then mixed with fly ash, cement, alkaline activator, etc., and ball-milled by a ball mill to form a raw material, wherein the mass fractions of the components in the raw material are as follows: 40% lithium mica slag, 25% fly ash, 25% cement, 5% composite alkaline activator (sodium hydroxide and potassium hydroxide in a mass ratio of 1:1), 3% additive (calcium oxide and calcium sulfate in a mass ratio of 1:1), and 2% hydrogen peroxide. The mass content of aluminum silicate in the lithium mica slag is 60%, the content of fluorine is 5%, the content of beryllium is 1000ppm, and the content of thallium is 1000ppm. (2) Add the raw material into a round pot granulator, and add water accounting for 30% of the raw material mass. Stir thoroughly for 22 minutes at room temperature and a speed of 30 r / min to obtain raw material balls.

[0053] (3) After natural curing at 22°C for 2 hours, the product was cured using a microwave for 8 minutes and then transferred to a steam curing box for steam curing at a temperature of 105°C and a humidity of 99.99% for 12 hours to obtain a lithium slag-based unburned lightweight aggregate.

[0054] Example 3 The present embodiment provides a lithium slag-based unburned light aggregate, and the preparation method thereof comprises the following steps: (1) The lithium mica slag is dried at 105°C to constant weight, and finally crushed by a wall breaking machine, and then sieved through a 500-mesh screen to obtain powder-grade lithium mica slag. The powdered lithium mica slag is then mixed with fly ash, cement, alkaline activator, etc., and ball-milled by a ball mill to form a raw meal, wherein the mass fractions of the components in the raw meal are as follows: 45% lithium mica slag, 25% fly ash, 20% cement, 5% composite alkaline activator (sodium hydroxide and potassium hydroxide in a mass ratio of 1:1, 3% auxiliary agent (calcium oxide and calcium sulfate in a mass ratio of 1:1), and 2% hydrogen peroxide. The mass content of aluminum silicate in the lithium mica slag is 45%, the content of fluorine is 5%, the content of beryllium is 1000ppm, and the content of thallium is 1000ppm.

[0055] (2) Add the raw material into a round pot granulator, and add water accounting for 30% of the raw material mass. Granulate it for 25 minutes at room temperature and a speed of 30 r / min to obtain raw material balls.

[0056] (3) After natural curing at 20°C for 3 h, the aggregate was transferred to a steam curing box and steam-cured for 24 h at a temperature of 105°C and a humidity of 99.99% to obtain lithium slag-based unburned lightweight aggregate.

[0057] Example 4 The present embodiment provides a lithium slag-based unburned light aggregate, and the preparation method thereof comprises the following steps: (1) The lithium mica slag is dried at 105°C to constant weight, and finally crushed by a wall breaker, and then sieved through a 500-mesh screen to obtain powder-grade lithium mica slag. The powdered lithium mica slag is then mixed with fly ash, cement, alkaline activator, etc., and ball-milled by a ball mill to form a raw material, wherein the mass fractions of the components in the raw material are as follows: 50% lithium mica slag, 25% fly ash, 15% cement, 5% composite alkaline activator (sodium hydroxide and potassium hydroxide in a mass ratio of 1:1), 3% additive (calcium oxide and calcium sulfate in a mass ratio of 1:1), and 2% hydrogen peroxide. The mass content of aluminum silicate in the lithium mica slag is 20%, the content of fluorine is 5%, the content of beryllium is 1000ppm, and the content of thallium is 1000ppm.

[0058] (2) Add the raw material into a round pot granulator, and add water accounting for 30% of the raw material mass. Granulate it for 20 minutes at room temperature and a speed of 30 r / min to obtain raw material balls.

[0059] (3) After natural curing at 23°C for 6 hours, the aggregate was transferred to a steam curing box and steam-cured for 24 hours at a temperature of 105°C and a humidity of 99.99% to obtain lithium slag-based unburned lightweight aggregate.

[0060] Example 5 The present embodiment provides a lithium slag-based unburned light aggregate, and the preparation method thereof comprises the following steps: (1) The lithium mica slag is dried at 105°C to constant weight, and finally crushed by a wall breaker, and then sieved through a 500-mesh screen to obtain powder-grade lithium mica slag. The powdered lithium mica slag is then mixed with fly ash, cement, alkaline activator, etc., and ball-milled by a ball mill to form a raw material, wherein the mass fractions of the components in the raw material are as follows: lithium mica slag 55%, fly ash 25%, cement 10%, composite alkaline activator 5% (sodium hydroxide and potassium hydroxide in a mass ratio of 1:1), auxiliary agent 3% (calcium oxide and calcium sulfate in a mass ratio of 1:1), and hydrogen peroxide 2%. The mass content of aluminum silicate in the lithium mica slag is 70%, the content of fluorine is 5%, the content of beryllium is 1000ppm, and the content of thallium is 1000ppm.

[0061] (2) Add the raw material into a round pot granulator, and add water accounting for 30% of the raw material mass. Granulate it for 20 minutes at room temperature and a speed of 30 r / min to obtain raw material balls.

[0062] (3) After natural curing at 22°C for 6 hours, the aggregate was transferred to a steam curing box and steam-cured for 24 hours at a temperature of 105°C and a humidity of 99.99% to obtain lithium slag-based unburned lightweight aggregate.

[0063] Comparative Example 1 This comparative example provides a lithium slag-based unburned lightweight aggregate. The main difference between the preparation method thereof and that of Example 4 is that in step (1), the fly ash content is 10% and the lithium mica slag content is 65%.

[0064] Comparative Example 2 This comparative example provides a lithium slag-based unburned lightweight aggregate. The preparation method thereof is different from that of Example 4 in that: in step (1), the fly ash content is 8%, the lithium mica slag content is 60%, and the cement content is 22%.

[0065] Comparative Example 3 This comparative example provides a lithium slag-based unburned lightweight aggregate. The preparation method thereof is different from that of Example 4 in that: in step (1), the fly ash content is 55%, the lithium mica slag content is 25%, and the cement content is 10%.

[0066] Comparative Example 4 This comparative example provides a lithium slag-based unburned lightweight aggregate. The main difference between the preparation method thereof and that of Example 4 is that in step (1), the fly ash content is 45%, the lithium mica slag content is 20%, and the cement content is 25%.

[0067] Comparative Example 5 This comparative example provides a lithium slag-based unburned lightweight aggregate. The main difference between the preparation method thereof and that of Example 4 is that in step (1), the fly ash content is 5% and the lithium mica slag content is 70%.

[0068] Application Examples The cylinder compressive strength, bulk density and water absorption of the lithium slag-based unburned light aggregate in each embodiment and comparative example were tested. The test method was based on GB / T17431.2-2010 "Light Aggregate and Its Test Method Part 2: Light Aggregate Test Method", and the light aggregate grade was based on GB / T 17431.2-2010 "Light Aggregate and Its Test Method Part 1: Light Aggregate". The specific test results are shown in Table 2: Table 2 Cylinder compressive strength, bulk density and water absorption of lithium slag-based unburned lightweight aggregates in various embodiments and comparative examples

[0069] The heavy metal content in the lithium slag-based unburned light aggregate in the embodiment and the comparative example was tested, and the test method was referred to the "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid Nitric Acid Method" (HJ / T299-2007); the heavy metal content of the sample was detected by ICP (inductively coupled plasma atomic emission spectrometry) and ICP-MS (ICP (inductively coupled plasma mass spectrometry). The leached heavy metal content was compared with the "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB 5085.3-2007).

[0070] Table 3 Toxicity of harmful metal leaching

[0071] From the above content, it can be seen that compared with the comparative example, the lithium slag-based unburned light aggregate in the embodiment of the present application has a low bulk density, high cylinder pressure strength, low water absorption rate, and a longer service life. And from Table 3, it can be seen that the heavy metal content in the leaching solution of the unburned lithium slag-based unburned light aggregate produced in this embodiment is compared with the "Hazardous Waste Identification Standard Leaching Toxicity Identification" (GB5085.3-2007), and both are less than the limit.

[0072] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A lithium slag-based unburned light aggregate, characterized in that: The raw materials include raw materials and water, wherein the raw materials include 25% to 60% of lithium mica slag, 10% to 50% of solid waste and 5% to 40% of cement by mass fraction; The lithium mica slag includes aluminosilicate, fluorine, beryllium and thallium; The components of the solid waste include, by mass, 10% to 70% silicon dioxide, 2% to 30% aluminum oxide, and 10% to 60% calcium oxide.

2. The lithium slag-based unburned light aggregate according to claim 1, characterized in that: The mass content of the silicon dioxide in the components of the solid waste is 50% to 70%; And / or, based on the mass of the lithium mica slag, the content of the fluorine element is not more than 5%, the content of the beryllium element is not more than 1000 ppm, and the content of the thallium element is not more than 1000 ppm.

3. The lithium slag-based unburned light aggregate according to claim 1, characterized in that: The mass content of the lithium mica slag in the raw material is 35% to 60%; and / or, The content of the cement in the raw material is 5% to 25%.

4. The lithium slag-based unburned light aggregate according to claim 1, characterized in that: Based on the mass of the lithium mica slag, the mass content of the aluminosilicate is 30% to 60%.

5. The lithium slag-based unburned light aggregate according to claim 1, characterized in that: The components of the raw material further include, by mass fraction, 0% to 5% of an auxiliary agent, 0% to 5% of an alkaline activator, and 0% to 5% of a foaming agent; the auxiliary agent includes at least one of calcium oxide and calcium sulfate.

6. The lithium slag-based unburned light aggregate according to claim 5, characterized in that: The alkaline activator includes at least one of sodium hydroxide, potassium hydroxide or calcium hydroxide.

7. The lithium slag-based unburned light aggregate according to claim 5, characterized in that: The foaming agent includes at least one of ammonium bicarbonate, aluminum powder, and hydrogen peroxide.

8. The lithium slag-based unburned light aggregate according to claim 1, characterized in that: The average particle size of the lithium slag-based unburned light aggregate is 2 mm to 15 mm.

9. A method for preparing lithium slag-based unburned light aggregate, characterized in that: It includes the following steps: S100, obtaining raw material, wherein the raw material comprises 25% to 60% of lepidolite slag, 10% to 50% of solid waste and 5% to 40% of cement; the lepidolite slag comprises aluminosilicate, fluorine, beryllium and thallium, and the solid waste comprises, by mass, 10% to 70% of silicon dioxide, 2% to 30% of aluminum oxide and 10% to 60% of calcium oxide; S200, mixing water and the raw material to granulate to obtain raw material balls; S300, curing the raw material balls to obtain lithium slag-based unburned light aggregate.

10. The method for preparing lithium slag-based unburned lightweight aggregate according to claim 9, characterized in that: In step S300, microwaves are used to pre-cure the raw balls.

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