Unfired lightweight aggregate with high lithium slag doping amount and method for synergistically preparing unfired lightweight aggregate from lepidolite slag and lepidolite slag

Abstract

The invention provides an unfired lightweight aggregate with high lithium slag doping amount and a method for synergistically preparing the unfired lightweight aggregate from lepidolite slag and lepidolite slag. The unfired lightweight aggregate with high lithium slag doping amount is prepared from the following raw materials: lithium slag and a functional additive, the lithium slag material comprises lepidolite slag and spodumene slag; the functional additive comprises a binder, an exciting agent and a mineralizing agent. Through cooperation of the lepidolite slag and the spodumene slag, the dry basis doping amount of the lithium slag in the unfired lightweight aggregate is increased to 80% or above, the cement doping amount is reduced to 15% or below, introduction of active components such as fly ash is not needed, the cement doping amount is low, the curing time is short, and high-doping-amount resource utilization of the lithium slag is achieved; the unfired lightweight aggregate has relatively high cylinder compressive strength and relatively low water absorption rate and bulk density, and meanwhile, efficient solidification of beryllium element is effectively realized in combination with a mineralizing agent; the material has excellent comprehensive performance and can be widely applied to the fields of building industry and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization and environmental protection materials, and relates to a non-fired lightweight aggregate with a high lithium slag content, and specifically relates to a non-fired lightweight aggregate with a high lithium slag content and a method for synergistically preparing the same by using lepidolite slag and spodumene slag. Background Art

[0002] With the rapid development of the lithium battery industry, a large amount of lithium slag is generated during the lithium ore mining and lithium battery production processes. Lepidolite 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°C). Moreover, the lithium slag contains a large amount of elements such as silicon, aluminum, and calcium. Landfilling will cause a large amount of resource waste. Therefore, how to harmlessly and resourcefully utilize lithium slag is of great significance to the healthy development of the lithium battery industry.

[0003] Artificial lightweight aggregates have advantages such as light weight, high strength, and excellent heat insulation performance, and are commonly used in building materials, thermal insulation materials, green environmental protection industries, and sanitary backfill, etc. CN 117185690A discloses a lithium slag-based non-fired lightweight ceramsite and its preparation method and application. The raw materials of the non-fired lightweight ceramsite include, by weight: 60 - 80 parts of spodumene lithium extraction 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 disposed is small. Due to the insufficient activity of spodumene slag, a large amount of quicklime and cement need to be added to prepare a non-fired lightweight aggregate with higher strength. 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% ground lithium slag, 10 - 20% siliceous material, 8 - 10% binder, and also include an activator accounting for 0 - 0.2% of the total mass of the binder, as well as 3 - 5% water and 5 - 10% modifier accounting for the total mass of the raw materials. This patent proposes a method for treating lepidolite slag. However, due to the insufficient pozzolanic component of lepidolite slag, it is necessary to additionally introduce siliceous material. This increases the production cost. In addition, using a single cement solidification method, the fixation of beryllium depends on physical encapsulation. During long-term use, due to the carbonation of C-S-H gel or acid rain erosion, the beryllium leaching concentration is prone to rebound, and the risk of exceeding the standard is significant.

[0004] In order to solve the problems such as insufficient disposal amount of lepidolite slag and spodumene slag, single beryllium fixation method, easy rebound of beryllium leaching concentration, and the need to supplement additional silicon source to increase cost mentioned above, it is necessary to provide a new type of non-fired lightweight aggregate. Summary of the Invention

[0005] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide a non-fired lightweight aggregate with a high lithium slag content and a method for synergistically preparing the same by using lepidolite slag and spodumene slag. The present invention synergistically utilizes lepidolite slag, spodumene slag and a mineralizer to solve the problems existing in the prior art, such as insufficient disposal amount of lepidolite slag and spodumene slag, single method for solidifying beryllium, easy rebound of beryllium leaching concentration, and the need to supplement additional silicon source to increase costs.

[0006] To achieve the purpose of this invention, the following technical solutions are adopted:

[0007] In the first aspect, the present invention provides a non-fired lightweight aggregate with a high lithium slag content. The raw materials for preparing the non-fired lightweight aggregate with a 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 a binder, an activator and a mineralizer.

[0009] By synergistically utilizing lepidolite slag and spodumene slag, the present invention can promote the occurrence of crystallization adhesion reaction to a greater extent, reduce the addition amount of cement and other pozzolanic active substances (such as slag powder, fly ash, etc.), generate more ettringite, C-S-H and C-A-S-H, thereby further improving the cylinder compressive strength of the non-fired lightweight aggregate; and by intermixing two kinds of lithium slags with complementary components of lepidolite slag and spodumene slag, the present invention can achieve a high lithium content with a total dry basis content > 80% in the non-fired lightweight aggregate, thereby reducing the usage amount of cement, slag powder and fly ash, and further realizing the resource utilization of high lithium slag content and reducing costs.

[0010] In addition, through the synergy of lattice fixation and physical barrier of the silicon-aluminum network structure, the deep mineralization and solidification of harmful elements such as beryllium are realized; the obtained non-fired lightweight aggregate has the advantages of high cylinder compressive strength, low water absorption, small bulk density, safety and stability, etc., and 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, in terms of mass fraction, the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content include: 30 - 70 wt% of lepidolite slag, 10 - 50 wt% of spodumene slag, 5 - 15 wt% of binder, 1 - 5 wt% of activator and 0 - 3 wt% of mineralizer.

[0012] Exemplarily, the content of lepidolite slag in the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content is 30 - 70 wt%, for example, it can be 30 wt%, 40 wt%, 50 wt%, 60 wt% or 70 wt%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0013] In the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content, the content of spodumene slag is 10-50 wt%, for example, it can be 10 wt%, 20 wt%, 30 wt%, 40 wt% or 50 wt% etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0014] In the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content, the content of the binder is 5-15 wt%, for example, it can be 5 wt%, 8 wt%, 11 wt% or 15 wt% etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0015] In the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content, the content of the activator is 1-5 wt%, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt% or 5 wt% etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0016] In the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content, the content of the mineralizer is 0-3 wt%, for example, it can be 0 wt%, 0.5 wt%, 1 wt%, 2 wt% or 3 wt% etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] It should be noted that when the leaching toxicity concentration of the lepidolite slag itself is extremely low, the mineralizer may not be added to achieve resource conservation.

[0018] As a preferred technical solution of the present invention, the water content of the lepidolite slag 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 numerical range are equally applicable.

[0019] Preferably, the water content of the spodumene slag 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 numerical range are equally applicable.

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

[0021] Preferably, the total content of lepidolite slag and spodumene slag in the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content 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 numerical range are equally applicable.

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

[0023] Exemplarily, the content of SiO2 in the lepidolite slag is 22 - 26%, for example, it can be 22%, 23%, 24%, 25% or 26%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0024] the content of Al2O3 in the lepidolite slag is 15 - 19%, for example, it can be 15%, 16%, 17%, 18% or 19%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0025] the content of SO3 in the lepidolite slag is 18 - 22%, for example, it can be 18%, 19%, 20%, 21% or 22%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0026] the content of CaO in the lepidolite 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, and other unlisted values within the numerical range are equally applicable;

[0027] the content of Na2O + K2O in the lepidolite 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, and other unlisted values within the numerical range are equally applicable.

[0028] The inevitable impurities in the lepidolite slag include components such as manganese, rubidium, cesium, fluorine, etc.

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

[0030] Exemplarily, the content of SiO2 in the spodumene slag is 42 - 48%, for example, it can be 42%, 44%, 45%, 46%, 47% or 48%, etc., but not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

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

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

[0033] The content of CaO in the spodumene slag is 11.5 - 15.5%, for example, it can be 11.5%, 12.5%, 13.5%, 14.5% or 15.5%, etc., but not limited to the listed values, and other unlisted values within the numerical range are equally applicable;

[0034] The content of Na2O + K2O 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 not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0035] It should be noted that the inevitable impurities in the spodumene slag include components such as manganese, rubidium, cesium, and fluorine.

[0036] As a preferred technical solution 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 - restrictive combinations include: the combination of calcium hydroxide and calcium oxide, the combination of calcium hydroxide, calcium oxide and calcium sulfate dihydrate, the combination of calcium sulfate dihydrate and carbide slag, or the combination of calcium hydroxide, calcium oxide, calcium sulfate dihydrate and carbide slag.

[0037] The activator of the present invention can provide an alkaline environment for the system, so that the silicate and aluminate in the lepidolite slag and spodumene slag dissolve and release silicate ions and aluminate ions under alkaline conditions, and form a three - dimensional network structure of C - A - H and C - A - S - H through recombination.

[0038] Preferably, the mineralizer includes calcium dihydrogen phosphate and / or calcium hydrogen phosphate.

[0039] Preferably, the binder includes cement.

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

[0041] In the present invention, by using phosphate (mineralizer), further mineralization of beryllium elements in lepidolite slag can be achieved (adding phosphate mineralizer to lightweight aggregates with high leaching toxicity); if the addition amount is too low, the mineralization effect of harmful elements will become low, and if the addition amount is too high, the strength of the obtained non-fired lightweight aggregates will decrease.

[0042] It should be noted that the synergistic effect of the lepidolite slag and spodumene slag provided by the present invention realizes the reduction of the bulk density and water absorption rate of the non-fired lightweight aggregates, and the improvement of the cylinder compressive strength; in addition, through chemical curing, efficient curing of beryllium elements in lepidolite slag is achieved, and the leaching rate of beryllium elements is reduced.

[0043] Specifically, the bulk density of the non-fired lightweight aggregates is 600~1100 kg / m 3 , for example, it can be 600 kg / m 3 , 700 kg / m 3 , 800 kg / m 3 , 900 kg / m 3 , 1000 kg / m 3 or 1100 kg / m 3 etc., but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0044] Preferably, the 1h water absorption rate of the non-fired lightweight aggregates is not higher than 15%, for example, it can be 14%, 13%, 10%, 9% or 8% etc., but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0045] Preferably, the cylinder compressive strength of the non-fired lightweight aggregates is 5~10.51 MPa, for example, it can be 5 MPa, 8 MPa, 9 MPa, 10 MPa or 10.51 MPa etc., but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0046] Preferably, the concentration of beryllium elements after toxicity leaching of the non-fired lightweight aggregates < 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 not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0047] In a second aspect, the present invention provides a preparation method of non-fired lightweight aggregates with a high lithium slag content as provided in the first aspect, and the preparation method includes the following steps:

[0048] (1) Mix lepidolite slag, spodumene slag and activator, and obtain composite slag after ball milling;

[0049] (2) Mix cement, mineralizer and the mixed slag obtained in step (1), and perform granulation treatment after stirring to obtain green balls.

[0050] (3) Perform steam curing on the green balls obtained in step (2) to obtain the non-fired lightweight aggregate with a high lithium slag content.

[0051] As a preferred technical solution of the present invention, the rotation speed of the ball milling 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 numerical range are equally applicable.

[0052] Preferably, the ball milling time in step (1) is 30-90 min. For example, it can be 30 min, 40 min, 50 min, 70 min or 90 min, etc., but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0053] Preferably, the average particle size of the composite slag in step (1) > 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 numerical range are equally applicable.

[0054] Preferably, the stirring time in step (2) is 20-40 min. For example, it can be 20 min, 25 min, 30 min, 35 min or 40 min, etc., but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0055] As a preferred technical solution of the present invention, the granulation treatment in step (2) includes disk granulation or roll pressing granulation.

[0056] Preferably, the rotation speed in the disk 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. Other unlisted values within the numerical range are equally applicable.

[0057] It should be noted that water mist is evenly sprayed during the disk granulation process to achieve the uniformity of granulation.

[0058] Preferably, the loading pressure in the roll pressing granulation is 1-5 kN. For example, it can be 1 kN, 2 kN, 3 kN, 4 kN or 5 kN, etc., but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0059] Preferably, the rotation speed in the roll 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 not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0060] It should be noted that during the granulation process in step (2) of the present invention, when the moisture content in the raw materials is relatively low, disk granulation is adopted, and by uniformly spraying water during the disk granulation process, the control of the moisture content in the green balls is achieved; when the moisture content in the raw materials is appropriate, roll granulation is adopted.

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

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

[0063] It should be noted that the moisture content of the green balls in the present invention is 25 - 30%. If the moisture content is too low, the raw materials will be loose and unable to be granulated and formed, and the later hydration effect will be poor; on the contrary, if the moisture content is too high, the raw materials will become pasty and unable to be formed.

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

[0065] Preferably, the time of the steam curing in step (3) is 4 - 12 h. For example, it can be 4 h, 6 h, 8 h, 10 h or 12 h, etc., but not limited to the listed values. Other unlisted values within the numerical range are equally 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 not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0067] In the present invention, steam curing is adopted to accelerate the hydration and crystallization adhesion reaction between the binder (cement) and lithium slag. Among them, if the temperature during the steam curing process is too high, it will cause the hydration and crystallization adhesion rate to be too fast, resulting in the expansion and cracking of lightweight aggregates. If the temperature is too low, the hydration and crystallization adhesion rate will be too slow.

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

[0069] (1) Mix lithium mica slag, spodumene slag and activator, and ball mill for 30 - 90 min at a rotation speed of 1200 - 1800 r / min to obtain a composite slag material with an average particle size > 80 mesh;

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

[0071] The granulation treatment includes disk granulation or roll pressing granulation;

[0072] (3) Carry out steam curing on the green balls obtained in step (2) for 4 - 12 h under the conditions of a temperature of 40 - 110 °C and a humidity of 90 - 99% to obtain the non-fired lightweight aggregate with a high lithium slag content.

[0073] The numerical ranges described in the present invention not only include the specific point values listed above, but also include any point values between the above numerical ranges not listed. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.

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

[0075] (1) By co-using lithium mica slag and spodumene slag, the present invention greatly increases the usage amount of lithium slag, reduces the usage of other raw materials such as silicon source, thereby reducing the production cost and achieving the purpose of cost reduction and efficiency increase;

[0076] (2) By using a mineralizer, the present invention realizes the chemical solidification of beryllium elements in lithium mica slag, and has a better solidification effect compared with the single physical solidification of cement;

[0077] (3) By utilizing the synergistic effect of lithium mica slag and spodumene slag in composition, the obtained non-fired lightweight aggregate has advantages such as strong cylinder compressive strength, low water absorption rate and bulk density, and has excellent comprehensive performance, and can be widely used in fields such as the construction industry. Detailed implementation manners

[0078] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

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

[0080] Table 1

[0081]

[0082] Among them, after the lepidolite slag is subjected to toxic leaching by the sulfuric acid-nitric acid method, the content of beryllium element detected by ICP-MS is 3.68 mg / L.

[0083] Example 1

[0084] This example provides a non-fired lightweight aggregate with a high content of lithium slag. In terms of mass fraction, the raw materials for preparing the non-fired lightweight aggregate with a high content of lithium slag include: 50 wt% of lepidolite slag, 35 wt% of spodumene slag, 8 wt% of binder, 5 wt% of activator, and 2 wt% of mineralizer;

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

[0086] The activator is calcium oxide; the mineralizer is calcium hydrogen phosphate; the binder is cement.

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

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

[0089] (2) Mix the cement, mineralizer and the mixed slag material obtained in step (1), stir for 30 min, and then carry out granulation treatment to obtain green balls with an average particle size of 20 mm and a water content of 28%;

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

[0091] (3) Carry out steam curing on the green balls obtained in step (2) for 10 h under the conditions of a temperature of 80°C and a humidity of 96% to obtain the non-fired lightweight aggregate with a high content of lithium slag.

[0092] Example 2

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

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

[0095] The activator is calcium hydroxide; the mineralizer is calcium dihydrogen phosphate; the binder is cement.

[0096] The method for co-preparing the non-fired lightweight aggregate with a high lithium slag content of this embodiment by using lepidolite slag and spodumene slag includes the following steps:

[0097] (1) Mix the lepidolite slag, spodumene slag and activator, and ball mill for 90 min at a rotation speed of 1200 r / min to obtain a composite slag material with an average particle size of 100 mesh;

[0098] (2) Mix the cement, mineralizer and the mixed slag material obtained in step (1), stir for 40 min and then carry out granulation treatment to obtain green balls with an average particle size of 10 mm and a water content of 25%;

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

[0100] (3) Carry out steam curing on the green balls obtained in step (2) for 12 h under the conditions of a temperature of 40 °C and a humidity of 90% to obtain the non-fired lightweight aggregate with a high lithium slag content.

[0101] Example 3

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

[0103] The water content of the lepidolite slag is 15%, and the water content of the spodumene slag is 30%. The water content in the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content 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 with a mass ratio of 1:1; the binder includes cement.

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

[0106] (1) Mix lepidolite slag, spodumene slag and activator, and ball mill for 30 min at a rotation speed of 1800 r / min to obtain a composite slag material with an average particle size of 170 mesh;

[0107] (2) Mix cement, mineralizer and the mixed slag material obtained in step (1), stir for 20 min and then carry out granulation treatment to obtain green balls with an average particle size of 30 mm;

[0108] The granulation treatment includes disk granulation or roll pressing granulation;

[0109] (3) Carry out steam curing on the green balls obtained in step (2) for 4 h under the conditions of a temperature of 110°C and a humidity of 90% to obtain the non-fired lightweight aggregate with a high lithium slag content.

[0110] Example 4

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

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

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

[0114] Example 5

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

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

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

[0118] Example 6

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

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

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

[0122] Example 7

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

[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 a high lithium slag content in this embodiment is the same as that in Example 1.

[0126] Example 8

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

[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 a high lithium slag content in this embodiment is the same as that in Example 1.

[0130] Example 9

[0131] This embodiment provides a non-fired lightweight aggregate with a high lithium slag content. The raw materials for preparing this non-fired lightweight aggregate are the same as those in Example 1.

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

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

[0134] Example 10

[0135] This embodiment provides a non-fired lightweight aggregate with a high lithium slag content. The raw materials for preparing this non-fired lightweight aggregate are the same as those in Example 1.

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

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

[0138] Example 11

[0139] This example provides a non-fired lightweight aggregate with a high lithium slag content. The raw materials for preparing the non-fired lightweight aggregate are the same as those in Example 1.

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

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

[0142] Comparative Example 1

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

[0144] In this comparative example, the spodumene slag is adjusted to 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 a high lithium slag content 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 a high lithium slag content. The difference between the non-fired lightweight aggregate and that in Example 1 is only that:

[0148] In this comparative example, the lepidolite slag is adjusted to 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 a high lithium slag content 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 a high lithium slag content. The difference between the non-fired lightweight aggregate and that in Example 1 is only that:

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

[0153] The preparation method of the non-fired lightweight aggregate with a high lithium slag content 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 a high lithium slag content. The difference between the non-fired lightweight aggregate and that in Example 1 is only that:

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

[0157] Performance detection:

[0158] (1) Detect the bulk density, 1h water absorption rate, and cylinder compressive strength of the non-fired lightweight aggregate with a high lithium slag content provided in the above-mentioned examples and comparative examples. The results are shown in Table 2;

[0159] (2) Perform toxicity leaching on the non-fired lightweight aggregate with a high lithium slag content provided in the above-mentioned examples and comparative examples by the sulfuric acid-nitric acid method, and then detect the beryllium element content by ICP-MS. The leaching amount results are shown in Table 2.

[0160] Table 2

[0161]

[0162] It can be seen from Table 2 that:

[0163] (1) Through comprehensive analysis of Examples 1-3, it can be seen that the present invention realizes the improvement of the cylinder compressive strength of the non-fired lightweight aggregate, the reduction of the water absorption rate and the bulk density, and effectively realizes the solidification of beryllium elements by synergistically using lepidolite slag and spodumene slag and using a mineralizer, and can be widely applied in fields such as the construction industry;

[0164] (2) Through comprehensive analysis of Example 1, Examples 4-6, and Comparative Examples 1-2, it can be seen that the present invention can control the bulk density and cylinder compressive strength of the non-fired lightweight aggregate by adjusting the dosage ratio of lepidolite slag and spodumene slag;

[0165] When the dosage of the lepidolite slag is too low or too high, it will cause a decrease in the cylinder compressive strength;

[0166] When the use of the lepidolite slag is omitted, due to insufficient pozzolanic activity, the generated three-dimensional network structure of C-A-H and C-A-S-H will be reduced, resulting in a decrease in the cylinder compressive strength; when the use of the spodumene slag is omitted, the insufficient supply of silicon and aluminum will lead to a reduction in the generated three-dimensional network structure of C-A-H and C-A-S-H, resulting in a decrease in the cylinder compressive strength;

[0167] (3) Through comprehensive analysis of Example 1, Examples 7-8, and Comparative Example 3, the mineralizer is one of the important factors affecting the solidification effect of beryllium elements. Specifically, by using chemical precipitation, the beryllium element in it reacts with phosphate and enters the hydroxyapatite lattice, and then through physical encapsulation of cement, double solidification is achieved;

[0168] When the dosage of the mineralizer is too low or even the mineralizer is not used, the solidification effect will be lacking due to insufficient physical solidification effect;

[0169] (4)Based on the comprehensive analysis of Example 1 and Examples 9 - 10, it can be seen that if the moisture content of the green balls is too low or too high, it will lead to a decrease in the cylinder compressive strength;

[0170] (5)Based on the comprehensive analysis of Example 1 and Example 11, it can be seen that too low humidity during the steam curing process will lead to insufficient moisture for the hydration reaction, thus affecting the formation of hydration products and resulting in a decrease in the cylinder compressive strength;

[0171] (6)Based on the comprehensive analysis of Example 1 and Comparative Example 4, although there is no obvious change in the physical properties of the lightweight aggregates with more spodumene slag replaced by fly ash, the cost of using fly ash as the raw material is relatively high, and it is impossible to achieve cost reduction and efficiency improvement and the purpose of treating lithium slag solid waste.

[0172] In summary, the present invention has achieved an improvement in the cylinder compressive strength of the non - fired lightweight aggregates, a decrease in the water absorption rate and bulk density by synergistically using lepidolite slag and spodumene slag, and at the same time, effectively achieved the high - efficiency solidification of beryllium elements in combination with a mineralizer; its comprehensive performance is excellent and can be widely applied in fields such as the construction industry.

[0173] The applicant declares that the above - mentioned specific embodiments have further elaborated on the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above - mentioned are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A non-fired lightweight aggregate with a high lithium slag content, characterized in that, The raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content include: lithium slag materials and functional additives; The lithium slag materials include lepidolite slag and spodumene slag; the functional additives include a binder, an activator, and a mineralizer.

2. The non-fired lightweight aggregate with a high lithium slag content according to claim 1, characterized in that, By mass fraction, the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content include: 30-70 wt% of lepidolite slag, 10-50 wt% of spodumene slag, 5-15 wt% of binder, 1-5 wt% of activator, and 0-3 wt% of mineralizer.

3. The non-fired lightweight aggregate with a high lithium slag content according to claim 2, characterized in that, The water content of the lepidolite slag is 15-30%; The water content of the spodumene slag is 15-30%; The water content in the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content is 25-30 wt%; The total content of lepidolite slag and spodumene slag in the raw materials for preparing the non-fired lightweight aggregate with a high lithium slag content is not less than 80 wt%.

4. The non-fired lightweight aggregate with a high lithium slag content according to claim 2, 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 mineralizer includes calcium dihydrogen phosphate and / or calcium hydrogen phosphate; The binder includes cement.

5. The non-fired lightweight aggregate with a high lithium slag content according to claim 4, characterized in that, The bulk density of the non-fired lightweight aggregate is 600~1100 kg / m 3 ; The 1h water absorption rate of the non-fired lightweight aggregate is not higher than 15%; The cylinder compressive strength of the non-fired lightweight aggregate is 5-10.51 MPa; The beryllium element concentration is <0.01 mg / L after the non-fired lightweight aggregate is subjected to toxicity leaching.

6. A method for synergistically preparing the non-fired lightweight aggregate with the high lithium slag content described in any one of claims 1 to 5 by using lepidolite slag and spodumene slag, characterized in that, The method includes the following steps: (1) Mix lepidolite slag, spodumene slag, and activator, and obtain a composite slag material after ball milling; (2) Mix cement, mineralizer, and the mixed slag material obtained in step (1), stir and then carry out granulation treatment to obtain green balls; (3) Carry out steam curing on the green balls obtained in step (2) to obtain the non-fired lightweight aggregate with a high lithium slag content.

7. The method according to claim 6, characterized in that, The rotation speed of the ball milling 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 min.

8. The method according to claim 6, wherein The granulation treatment in step (2) includes disk granulation or roll pressing granulation; The rotation speed in the disk granulation is 20-30 r / min; The loading pressure in the roll pressing granulation is 1-5 kN; The rotation speed in the roll pressing granulation is 100-200 r / min; The average particle size of the green balls in step (2) is 5-30 mm; The water content of the green balls in step (2) is 25-30%; 9. The method according to claim 6, wherein The temperature of the steam curing in step (3) is 40-110 °C; The time of the steam curing in step (3) is 4-12 h; The humidity of the steam curing in step (3) is 90-99%; 10. The method according to claim 6, wherein The method includes the following steps: (1) Mix lepidolite slag, spodumene slag, and activator, and obtain a composite slag material with an average particle size of >80 mesh after ball milling for 30-90 min under the rotation speed condition of 1200-1800 r / min; (2) Mix cement, mineralizer, and the mixed slag material obtained in step (1), stir for 20-40 min and then carry out granulation treatment to obtain green balls with an average particle size of 5-30 mm; The granulation treatment includes disk granulation or roll pressing granulation; (3) The green balls obtained in step (2) are subjected to steam curing for 4 to 12 h under the conditions of a temperature of 40 to 110 °C and a humidity of 90 to 99% to obtain the non-fired lightweight aggregate with a high lithium slag content.

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