Method for photovoltaic preparation of aerated concrete for wall material from lithium tailings-vanadium-titanium slag-waste

Abstract

The invention relates to the technical field of comprehensive utilization of resources, in particular to a method for photovoltaic preparation of aerated concrete for a wall material from lithium tailings-vanadium-titanium slag-waste. The low-carbon powder prepared from the steel solid waste, the power industry solid waste, the non-metallic mineral solid waste and the nonferrous metallurgy solid waste is combined with the mineral composition and content characteristics of the novel low-carbon cement clinker, and the portland cement clinker is replaced; chemical industrial solid waste is used for replacing all calcium raw material quicklime; the lithium ore tailings are used as a high-silicon raw material to replace the traditional silicon raw materials, namely river sand and fly ash; ardealite / fluorgypsum is used for replacing gypsum to serve as a retarder. The mechanical property index, the physical property index and the durability index of the prepared aerated concrete all meet the requirements in the standard of autoclaved aerated concrete blocks GB / T 11968-2020, the utilization rate of industrial solid waste reaches 100%, and the production cost of enterprises is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive utilization of resources, and particularly relates to a method for preparing aerated concrete for wall materials from lithium tailings-vanadium-titanium mine slag-waste photovoltaics. BACKGROUND

[0002] Autoclaved aerated concrete (AAC; phase composition and chemical molecular formula: tobermorite-5CaO·6SiO2·nH2O) is a kind of light-weight porous wall material, which is made of calcareous material (lime, cement), siliceous material (river sand, quartz sand, fly ash, etc.), water, additives and a proper amount of gas-forming agent, through processes such as batching, stirring, pouring, pre-curing, cutting, autoclaving and curing. The advantage of aerated concrete lies in its light weight, with a porosity of 70%~85% and a bulk density of 500kg / m 3 ~700kg / m 3 , which is only 1 / 5 of ordinary concrete, 1 / 3 of hollow clay bricks and 1 / 4 of solid clay bricks, and can float on water. Autoclaved aerated concrete contains a large number of bubbles and micropores, so it has good thermal insulation performance, with a thermal conductivity of 0.09W / (m·K)~0.17W / (m·K), which is 3~4 times that of clay bricks and 4~8 times that of ordinary concrete. Aerated concrete is mainly used for frame structures, filling of external walls of cast-in-place concrete, internal wall partitioning, and can also be used for external walls of multi-story buildings with seismic ring beam structure or thermal insulation composite walls, and can also be used for thermal insulation and insulation of building roofs.

[0003] Vanadium-titanium mine slag is a waste slag produced during the smelting of vanadium-titanium magnetite in a blast furnace, and the main chemical components of vanadium-titanium mine slag are similar to those of ordinary slag, mainly including CaO, SiO2, Al2O3 and MgO, but the content of TiO2 in vanadium-titanium mine slag is relatively high, and the content of CaO is relatively low, which results in a higher polymerization degree of siloxane tetrahedron (glass body) in vanadium-titanium mine slag, a large “crystal-glass ratio” and a smaller activity than ordinary slag, so the application of vanadium-titanium mine slag is limited. A large amount of vanadium-titanium mine slag is accumulated, which not only occupies land, but also causes waste of resources and environmental pollution.

[0004] Lithium tailings are solid waste left over after lithium is extracted from lithium ore. The main components of lithium tailings are minerals such as silicon dioxide, aluminum oxide and calcium oxide, and also contain a small amount of lithium, potassium, sodium and iron elements. Lithium tailings can be used to produce ceramics, ferrosilicon alloy, water glass, inorganic glue, microcrystalline glass and other materials. Although lithium tailings have certain utilization value, the treatment and utilization of lithium tailings also have some environmental problems. First of all, the storage problem of lithium tailings, lithium tailings stored in open-air sites are easily affected by weathering, rain and other natural factors, which can lead to the dissolution of some harmful substances in the tailings, affecting the water quality and soil quality of the surrounding environment. In addition, if the traditional landfill method is used to treat lithium tailings, it is easy to cause large land occupation and environmental impact. Therefore, the research and application of more environmentally friendly and efficient lithium tailings treatment technology has important significance.

[0005] Therefore, if vanadium-titanium slag and lithium tailings are effectively utilized as raw materials for the preparation of aerated concrete, both the environmental problems caused by long-term accumulation of solid waste and the raw material cost problems of aerated concrete can be solved, which has great significance. SUMMARY

[0006] Therefore, the purpose of the present application is to provide a method for preparing aerated concrete for wall materials from lithium tailings-vanadium-titanium slag-waste photovoltaic, which not only improves the utilization rate of industrial solid waste, but also solves the raw material cost problem of aerated concrete.

[0007] The present application solves the above technical problems by the following technical means: The present application provides a method for preparing aerated concrete for wall materials from lithium tailings-vanadium-titanium slag-waste photovoltaic, comprising the following steps: To prepare the first mixed particles, the causticizing mud for papermaking and the desulfurization ash were pretreated separately. The pretreated causticizing mud for papermaking and the desulfurization ash were mixed at a mass ratio of (1~3):(2~3) to obtain the first mixed particles. To prepare gold mine tailings particles, the gold mine tailings were screened, crushed to a particle size ≤2mm, and dried to constant weight to obtain gold mine tailings particles. To prepare waste photovoltaic panel particles, the waste photovoltaic panels were washed, dried, and crushed to a particle size ≤2mm to obtain waste photovoltaic panel particles. To prepare the second mixed particles, steel slag and vanadium-titanium ore slag were screened, crushed to a particle size ≤2mm, and dried to constant weight. To obtain a second mixed particle with a particle size ≤2mm, the dried steel slag and vanadium-titanium ore slag were mixed at a mass ratio of (1~2):(1~2). To prepare a third mixed particle, aluminum ash slag and refining slag were screened, crushed to a particle size ≤2mm, dried to a constant weight, and then mixed at a mass ratio of (2~4):(1~3) to obtain a third mixed particle with a particle size ≤2mm. To prepare low-carbon powder, the first mixed particle, gold mine tailings particles, waste photovoltaic panel particles, the second mixed particle, and the third mixed particle were mixed and ground to a specific surface area of ​​300~400m². 2 / kg, to obtain a mixed dry material, add water at 8-10% of the mass of the mixed dry material, mix evenly, form into pellets, dry, and then calcine the dried pellets at high temperature, followed by two-stage cooling to room temperature. The resulting calcined product is crushed to ≤2mm particles and ground to a specific surface area of ​​400-500m². 2 / kg, to obtain low-carbon powder; prepare a second powder, remove impurities from phosphogypsum and fluorogypsum respectively, dry to constant weight, mix the dried phosphogypsum and fluorogypsum at a mass ratio of (2~4):(1~2), and grind to a specific surface area of ​​300~400m². 2 / kg, to obtain the second powder; to prepare the third powder, remove impurities from the calcium silicate slag and the alkali slag separately, dry to constant weight, mix the dried calcium silicate slag and alkali slag at a mass ratio of (1~3):1 to obtain mixed slag powder, add 8~10% water by mass of the mixed slag powder, mix evenly, form into cakes, dry, calcine the dried cakes, cool, and grind to a specific surface area of ​​400~500m². 2 / kg, to obtain the third powder; to prepare the fourth powder, the lithium tailings were purified, dried to a moisture content of 3-10%, then dried to constant weight, and ground to a specific surface area of ​​400-500 m². 2 / kg, to obtain the fourth powder; for molding and curing, take the low carbon powder, the second powder, the third powder and the fourth powder and mix them evenly to obtain the mixed powder. Add warm water and foam stabilizer and stir, then add aluminum powder and stir to obtain the mixed slurry. At the mold temperature of 45~50℃, pour the mixed slurry into the mold, and then perform static gas generation, pre-curing, green body cutting and high temperature autoclaving to obtain the aerated concrete product.

[0008] The second aspect of the present invention provides an aerated concrete for preparing wall materials from lithium tailings-vanadium-titanium slag-waste photovoltaic materials, which is prepared by the method described in the first aspect above.

[0009] This invention utilizes low-carbon powder prepared from iron and steel solid waste, power industry solid waste, non-metallic mineral solid waste, and non-ferrous metallurgical solid waste. It combines the mineral composition and content characteristics of novel low-carbon cement clinker, replacing silicate cement clinker. Chemical industry solid waste replaces all calcareous quicklime; lithium mine tailings are used as a high-silica raw material, replacing traditional siliceous raw materials such as river sand and fly ash; and phosphogypsum / fluorogypsum replaces gypsum as a retarder. The mechanical properties (compressive strength), physical properties (dry density, drying shrinkage, thermal conductivity), and durability properties (frost resistance) of the prepared aerated concrete all meet the requirements of the GB / T 11968-2020 standard for "Autoclaved Aerated Concrete Blocks," effectively improving the utilization rate of industrial solid waste and demonstrating significant environmental and economic benefits.

[0010] In the method for preparing aerated concrete for wall materials using lithium tailings, vanadium-titanium slag, and waste photovoltaic materials of this invention, the lithium tailings, after testing, meet the requirements of JC / T 622-2009 "Sand for Silicate Building Products" and can replace the need for river sand and fly ash in traditional aerated concrete production. The calcium-based raw materials prepared using calcined calcium silicate slag and alkali slag meet the technical requirements of "Quicklime for Silicate Building Products" (JC / T 621-2021), and its calcination temperature reduces energy consumption by more than 10% compared to quicklime preparation.

[0011] The present invention discloses a method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials. In the low-carbon powder preparation step, using calcareous materials (papermaking causticized mud, desulfurization ash), siliceous materials (gold mine tailings, waste photovoltaic panels), and ferroaluminous materials (steel slag, vanadium-titanium slag) as raw materials, the method controls process parameters (particle size, molding conditions, calcination temperature, and holding time) to form a specific crystalline structure in the calcined product, achieving excellent early, mid, and late-stage performance, and allowing it to replace silicate cement clinker. The prepared low-carbon powder exhibits significant carbon reduction. Its calcination incorporates papermaking causticized mud containing a large amount of organic matter and cellulose, reducing the calcination temperature by 100°C compared to silicate cement clinker, and lowering energy consumption by more than 10%. Furthermore, the calcination process uses all solid waste raw materials, without limestone, reducing CO2 emissions by more than 20%, significantly lowering enterprise production costs.

[0012] The method for preparing aerated concrete for wall materials from lithium tailings-vanadium-titanium slag-waste photovoltaic materials of this invention optimizes the porosity of aerated concrete by controlling process parameters such as raw material particle size, pouring temperature, application of foam stabilizer, and static stopping temperature and autoclaving temperature. This results in a porosity of 72%~83%. These pores block capillary channels during freeze-thaw cycles, reducing water penetration paths and lowering the water saturation in the pores (below the critical value of 91.7%). This reduces the structural damage caused by ice crystal expansion during freeze-thaw cycles and improves the freeze-thaw resistance of the aerated concrete. The high porosity of the aerated concrete reduces its dry density, while its well-developed capillary structure and long, dispersed water evaporation paths lead to low water loss and reduced drying shrinkage. The uniformly distributed micropores within the aerated concrete significantly reduce the heat conduction path, resulting in a thermal conductivity ≤0.13 W / (m·K), far lower than GB / T. The requirement of ≤0.16 W / (m·K) is specified in standard 11968-2020.

[0013] Tests have shown that the wall materials A3.5, B06, and aerated concrete prepared by the method of this invention possess high compressive strength, reaching up to 5.06 MPa (far exceeding the compressive strength requirement of ≥3.5 MPa in GB / T 11968-2020 standard), and a thermal conductivity as low as 0.10 W / (m·K) (far below the requirement of ≤0.16 W / (m·K) in GB / T 11968-2020 standard). They also exhibit excellent frost resistance, with post-freezing strength loss as low as 11.8% and post-freezing mass loss as low as 2.3%. The drying shrinkage value of aerated concrete can be as low as 0.31 mm / m (far below the requirement of ≤0.50 mm / m in GB / T 11968-2020 standard), effectively ensuring the stability of wall quality in engineering applications. Attached Figure Description

[0014] Figure 1 This is an XRD pattern of gold mine tailings; Figure 2 This is the XRD pattern of steel slag; Figure 3 This is the XRD pattern of vanadium-titanium ore slag; Figure 4 This is the XRD pattern of calcium silicate slag; Figure 5 This is the XRD pattern of lithium mine tailings; Figure 6 These are the XRD patterns of the high-temperature calcination products under different holding times; Figure 7 This is the SEM image of sample M2; Figure 8 This is the EDS plot of sample M2; Figure 9 This is the XRD pattern of the aerated concrete product of Example 2; Figure 10 This is an FT-IR image of the aerated concrete product of Example 2; Figure 11 This is a SEM image of the aerated concrete product of Example 2;Figure 12 yes Figure 11 EDS spectrum of region 3 in the middle. Detailed Implementation

[0015] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0016] This application uses industrial solid waste as raw material, as detailed below: The mineral composition of gold mine tailings is quartz, calcite, and dolomite, and its XRD pattern is shown below. Figure 1 As shown. The mineral composition of steel slag is C2S, C3S, RO phase, C2F, C 12 A7, f-CaO, etc., their XRD patterns are as follows: Figure 2 As shown. Vanadium-titanium slag is a waste residue produced during blast furnace ironmaking using vanadium-titanium magnetite as raw material. Its main mineral composition is magnesium rhodochrosite and perovskite, and its XRD pattern is shown in the figure. Figure 3 As shown. The main mineral composition of the silica-calcium slag is: quartz, C2S, calcite, and mullite, and its XRD pattern is shown in the figure. Figure 4 As shown. The main mineral composition of lithium tailings is quartz, albite, and microcline, and its XRD pattern is shown in the figure. Figure 5 As shown.

[0017] The method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials disclosed in this application includes the following steps: S1. Prepare the first mixed particles by pretreating the causticizing mud and desulfurization ash from papermaking, and then mixing the pretreated causticizing mud and desulfurization ash in a mass ratio of (1~3):(2~3) to obtain the first mixed particles. S2. Prepare gold mine tailings particles by screening and crushing the gold mine tailings to a particle size ≤2mm, and drying them to constant weight. S3. Prepare waste photovoltaic panel particles by cleaning and drying the waste photovoltaic panels, and then crushing them to a particle size ≤2mm. S4. Prepare the second mixed particles by screening and crushing the steel slag and vanadium-titanium ore slag to a particle size ≤2mm, and then drying them to constant weight. The dried steel slag and vanadium-titanium ore slag are then mixed in a mass ratio of (1~2):(1~2) to obtain the second mixed particles with a particle size ≤2mm. S5. Prepare the third mixed particles: screen and crush aluminum ash slag and refining slag to a particle size ≤2mm, dry them to constant weight, and mix the dried aluminum ash slag and refining slag at a mass ratio of (2~4):(1~3) to obtain the third mixed particles with a particle size ≤2mm. S6. Prepare low-carbon powder: take the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles, and third mixed particles, mix them, and grind them to a specific surface area of ​​300~400m². 2 / kg, to obtain a mixed dry material, add water at 8-10% of the mass of the mixed dry material, mix evenly, form into pellets, dry, and then calcine the dried pellets at high temperature, followed by two-stage cooling to room temperature. The resulting calcined product is crushed to ≤2mm particles and ground to a specific surface area of ​​400-500m². 2 / kg, to obtain low-carbon powder. S7. Prepare the second powder by removing impurities from phosphogypsum and fluorogypsum respectively, drying to constant weight, mixing the dried phosphogypsum and fluorogypsum at a mass ratio of (2~4):(1~2), and grinding to a specific surface area of ​​300~400m². 2 / kg, to obtain the second powder. S8. Prepare the third powder by removing impurities from the calcium silicate slag and the alkali slag, drying them to constant weight, mixing the dried calcium silicate slag and alkali slag at a mass ratio of (1~3):1 to obtain mixed slag powder, adding 8~10% water by mass of the mixed slag powder, mixing evenly, forming a cake, drying it, calcining the dried cake, cooling it, and grinding it to a specific surface area of ​​400~500m². 2 / kg, to obtain the third powder. S9. To prepare the fourth powder, the lithium tailings are cleaned of impurities, dried to a moisture content of 3-10%, then dried to constant weight, and ground to a specific surface area of ​​400-500 m². 2 / kg, to obtain the fourth powder. S10. Molding and curing: Take the low-carbon powder, the second powder, the third powder and the fourth powder and mix them evenly to obtain a mixed powder. Add warm water and foam stabilizer and stir. Then add aluminum powder and stir to obtain a mixed slurry. At the mold temperature of 45~50℃, pour the mixed slurry into the mold. Then perform static gas generation, pre-curing, green body cutting and high temperature autoclaving to obtain aerated concrete products.

[0018] The present invention discloses a method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials. This method uses a variety of industrial solid wastes, including papermaking causticizing mud, desulfurization ash, gold mine tailings, waste photovoltaic panels, steel slag, vanadium-titanium slag, aluminum ash, refining slag, phosphogypsum, fluorogypsum, calcium silicate slag, alkali slag, and lithium tailings, to replace the traditional raw materials for aerated concrete production. This method not only solves the problem of raw material shortage in aerated concrete production in some areas, but also effectively recycles and utilizes various industrial solid wastes, avoiding resource waste.

[0019] In some embodiments, the pretreatment of papermaking causticizing sludge is as follows: the papermaking causticizing sludge is piled up and air-dried until the moisture content is 15-25%, then dried to constant weight, and subsequently dispersed in a planetary ball mill to particles with a diameter ≤2mm. The pretreatment of desulfurization ash is as follows: the desulfurization ash is crushed to 1-3mm particles, dried to constant weight, and then dispersed in a planetary ball mill to particles with a diameter ≤2mm.

[0020] In some embodiments, the mass ratio of the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles, and third mixed particles is (60~77):(10~15):(5~10):(5~10):(3~5). The high-temperature calcination in the preparation of the low-carbon powder is as follows: heating to 800℃ at a rate of 5℃ / min, holding for 20min, then heating to 1200~1300℃ at a rate of 10℃ / min, holding for 30~60min. The two-stage cooling to room temperature is as follows: under wind conditions of 5~8m / s, cooling to 1000℃ at a rate of 18~20℃ / min, then cooling to room temperature at a rate greater than or equal to 100℃ / min. The two-stage cooling to room temperature is to improve the quality of low-carbon powder by controlling the cooling temperature. Specifically, the slow cooling in the first stage controls the formation of C2S in the powder; after slow cooling, it is cooled from 1000℃ to room temperature at a rate of not less than 100℃ / min to obtain low-carbon powder with better mechanical properties in the early, middle and late stages than ordinary silicate cement clinker.

[0021] In some embodiments, the thickness of the cake in the third powder preparation step is 1-2 cm and the diameter is 4-6 cm. The cake is then dried at a constant temperature of 100°C for 25-40 min. The calcination conditions in the third powder preparation step are: heating to 250°C at a heating rate of 5°C / min and holding for 20-30 min, then heating to 750-850°C at a heating rate of 5°C / min and holding for 25-35 min.

[0022] In some embodiments, the mass ratio of the low-carbon powder, the second powder, the third powder, and the fourth powder is (9~12):(6~10):(15~23):(55~70). The warm water is water with a temperature of 52~62℃, and the total amount of the warm water is 55~65% of the mass of the mixed powder. The amount of the foam stabilizer is 5~12‰ of the total mass of the warm water, and the amount of aluminum powder is 0.5~0.7‰ of the mass of the mixed powder. The foam stabilizer is prepared from distilled water, sodium stearoyl lactylate, and trinitrotoluene, with a corresponding mass ratio of 89.9:2.8:7.3. The aluminum powder has an active Al content ≥93%, a sieve residue of ≤2.6% on a 0.08mm square hole sieve, a gas generation rate >84%, a gas generation time <25min, and a hydrophilicity of less than 19s.

[0023] In some embodiments, the static gas generation and pre-curing time are both 3~5h, and the pre-curing temperature is 55~68℃; the high-temperature autoclaving process is as follows: sealing, vacuuming, heating to 180~195℃, pressure of 1.15~1.25MPa, constant temperature and pressure for 6~8h, and then cooling to room temperature and pressure.

[0024] The following examples, 1-3, provide a detailed description of the method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials according to this application: Example 1

[0025] The method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials in this embodiment includes the following steps: S1. Preparation of the first mixed particles: The causticizing mud for papermaking is piled up and dried, stirred twice a day to achieve a moisture content of 18%. It is then placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried mud is then placed in a planetary ball mill and dispersed at 200 r / min for 15 min until particles with a diameter ≤2 mm are formed. Desulfurization ash is placed in a jaw crusher with a feed size ≤250 mm and a discharge size ≤10 mm. The desulfurization ash is crushed to 1-3 mm particles, then placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried desulfurization ash particles are then placed in a planetary ball mill and dispersed at 200 r / min for 15 min until particles with a diameter ≤2 mm are formed. The pretreated papermaking causticizing mud and desulfurization ash were added to a planetary ball mill at a mass ratio of 3:2 and ball-milled at a speed of 200 r / min for 15 min to obtain the first mixed particles.

[0026] S2. Preparation of gold tailings particles: Gold tailings are screened using a vibrating screen to remove impurities, and then screened to obtain gold tailings particles >2mm and ≤2mm. The gold tailings particles >2mm are then fed into a jaw crusher with a feed size ≤250mm and an output size ≤10mm. The gold tailings particles >2mm are crushed to ≤2mm particles, and then mixed with the ≤2mm gold tailings particles obtained from the screening. The mixture is then placed in an electric heating drying oven and dried at 105℃ to constant weight to obtain gold tailings particles with a particle size ≤2mm for later use.

[0027] S3. Preparation of waste photovoltaic panel granules: Remove the aluminum frame and adhesive strips from the waste photovoltaic panels, then remove impurities adsorbed on the surface of the photovoltaic panels using high-pressure water. After natural drying, hammer the waste photovoltaic panels to a length <18cm and an area <360cm². 2 The blocks are placed into a jaw crusher. The jaw crusher is set with a feed size of ≤250mm and a discharge size of ≤10mm. The waste photovoltaic blocks are crushed into particles of ≤2mm to obtain waste photovoltaic panel particles for later use.

[0028] S4. Preparation of the second mixed particles: Steel slag and vanadium-titanium ore slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight, corresponding to steel slag and vanadium-titanium ore slag with a particle size ≤2mm. Then, steel slag and vanadium-titanium ore slag are placed in a planetary ball mill at a mass ratio of 1:2 and ball milled at a speed of 200r / min for 15min to obtain the second mixed particles with a particle size ≤2mm.

[0029] S5. Preparation of the third mixed particles: Aluminum ash slag and refining slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight to obtain aluminum ash slag and refining slag with particle size ≤2mm. Then, aluminum ash slag and refining slag are mixed in a planetary ball mill at a mass ratio of 2:3 to obtain the third mixed particles with a particle size ≤2mm.

[0030] S6. Preparation of low-carbon powder: Take the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles, and third mixed particles, mix them at a mass ratio of 63:14:(5~10):9:4, put them into a ball mill, and grind the materials to a specific surface area of ​​300m². 2 / kg, to obtain a mixed dry material, put the mixed dry material into a cement mortar mixer, and add water in two batches, each accounting for 8% of the mass of the mixed dry material. The first addition of 75% is mixed for 60 seconds, and the second addition of 25% is mixed for 120 seconds. The resulting mixture is placed in a mold, and the hydraulic press is set to a pressure of 18 MPa to press the mixture into pellets (pellet size Φ30mm × 20mm). The pellets are placed in an electric heating forced-air drying oven and dried at 100℃ for 15 minutes. The dried pellets are placed in a covered corundum crucible, and then the crucible is placed in a muffle furnace for high-temperature calcination. The high-temperature calcination regime in this embodiment is as follows: heating to 800℃ at a heating rate of 5℃ / min, holding for 20 minutes, heating to 1200℃ at a heating rate of 10℃ / min, and holding for 35 minutes. After calcination, the temperature was lowered to 1000℃ at a rate of 18℃ / min under a wind speed of 5 m / s, and then cooled to room temperature at a rate of 100℃ / min. The resulting high-temperature calcined product was crushed into ≤2mm particles in a jaw crusher, and then transferred to a cement ball mill at a speed of 48 r / min to grind the high-temperature calcined product to a specific surface area of ​​400 m². 2 / kg, to obtain low-carbon powder.

[0031] The chemical composition of the low-carbon powder in this embodiment is shown in Table 1: Table 1. Chemical composition of the low-carbon powder of Example 1

[0032] The activity index of the low-carbon powder in this embodiment is shown in Table 2: Table 2. Activity index of the low-carbon powder in Example 1

[0033] S7. Preparation of the second powder: Phosphogypsum and fluorogypsum are sieved separately using a vibrating screen to remove impurities. Then, they are placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried phosphogypsum and fluorogypsum are then mixed evenly at a mass ratio of 4:1 and placed in a cement ball mill, where they are ground at 48 r / min to a specific surface area of ​​300 m². 2 / kg, to obtain the second powder.

[0034] The second powder in this embodiment meets the technical specifications specified in GB / T 21371-2019 "Industrial By-product Gypsum for Cement". The second powder contains 83% CaSO4·2H2O and 83% CaSO4 (the specification requires ≥75%), 0.41% chloride ion content (the specification requires ≤0.5%), a pH value of 4.5 (the specification requires ≤5), and radioactive material limits that meet the requirements of GB 6566 (internal exposure index ≤1.0, external exposure index ≤1.0).

[0035] S8. Preparation of the third powder: The silicon-calcium slag and the alkali slag are screened to remove impurities, and the organic impurities are removed. Then, the silicon-calcium slag and the alkali slag are placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried silicon-calcium slag and alkali slag are mixed evenly at a mass ratio of 1:1 to obtain mixed slag powder. The mixed slag powder was placed in a cement mortar mixer and stirred for 5 minutes. During this time, water, accounting for 8% of the total dry mass, was added in two batches: 75% for the first addition and 25% for the second. After thorough mixing, the wet mixture was placed in a mold and pressed into a cake with a thickness of 1 cm and a diameter of 4 cm using a hydraulic press at a pressure of 18 MPa. The cake was then placed in an electric heating forced-air drying oven and dried at a constant temperature of 100℃ for 25 minutes. The dried cake was then placed in a covered corundum crucible and calcined in a muffle furnace. The calcination process involved raising the temperature to 250℃ at a rate of 5℃ / min, holding for 20 minutes, and then raising it to 750℃ at a rate of 5℃ / min and holding for 25 minutes. After calcination, the cake was cooled to room temperature at a rate of 18℃ / min under a wind speed of 5 m / s. The cooled cake was then ground in a cement ball mill to a specific surface area of ​​400 m². 2 / kg, to obtain the third powder. The physicochemical properties of the third powder are shown in Table 3.

[0036] Table 3. Physicochemical properties of the third powder in Example 1

[0037] Note: In Table 3 1 The grade 1 refers to the technical specifications of "Quicklime for Silicate Building Products" JC / T 621-2021.

[0038] S9. Preparation of the fourth powder: The lithium tailings are screened to remove organic impurities and mud lumps. The screened and impurity-removed lithium tailings are piled up in a cool place to dry, stirred twice a day to reduce the moisture content to below 8%, and then placed in an electric heating forced-air drying oven at 105℃ to constant weight. Finally, they are placed in a cement ball mill and ground to a specific surface area of ​​400 m². 2 / kg, yielding the fourth powder. The technical specifications of this fourth powder are shown in Table 4: Table 4. Technical specifications of the fourth powder in Example 1

[0039] Note: In Table 4 2 The grade 2 refers to the technical specifications of JC / T 622-2009, "Sand for Silicate Building Products".

[0040] S10. Molding and Curing: Take low-carbon powder, second powder, third powder and fourth powder, add them to the mixing tank in a mass ratio of 9:9:16:66, stir and mix well to obtain mixed powder. Add 55% of the total mass of the mixed powder, 58℃ warm water and 7‰ of the total amount of warm water, and stir for 100s. Then add 0.5‰ of the total mass of the mixed powder, aluminum powder, and stir for 40s to obtain a uniformly mixed slurry. During the stirring process, set up heat preservation measures to ensure that the temperature of the slurry when pouring into the mold is 45℃. Pour into the mold, then let it stand still for 3 hours to generate gas, and pre-cur at 60℃ for 3 hours. Cut the green body, then seal, vacuum, heat to 180℃, pressure 1.15MPa, and keep at constant temperature and pressure for 6 hours. Then reduce to normal temperature and pressure to complete the high-temperature autoclaving curing to obtain aerated concrete products.

[0041] The radioactivity test results of the mixed powder in step S10 of this embodiment are shown in Table 5: Table 5. Radioactivity test results of the mixed powder in step S10 of Example 1

[0042] Note: In Table 5 3 The number 3 in the remarks refers to the test index requirements in GB 6566-2010, "Limits of Radionuclides in Building Materials".

[0043] Example 2 The method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials in this embodiment includes the following steps: S1. Preparation of the first mixed particles: The causticizing mud for papermaking is piled up and dried, stirred twice a day, until its moisture content is 22%. Then it is placed in an electric heating blast drying oven and dried at 105℃ to constant weight. The dried mud is then placed in a planetary ball mill and dispersed at a speed of 200 r / min for 17 min until the particle size is ≤2 mm. The desulfurization ash is placed in a jaw crusher with a feed particle size ≤250 mm and a discharge particle size ≤10 mm. The desulfurization ash is crushed into 1~3 mm particles and then placed in an electric heating blast drying oven and dried at 105℃ to constant weight. The dried desulfurization ash particles are then placed in a planetary ball mill and dispersed at a speed of 200 r / min for 17 min until the particle size is ≤2 mm. The pretreated papermaking causticizing mud and desulfurization ash were added to a planetary ball mill at a mass ratio of 1:2 and ball-milled at a speed of 200 r / min for 17 min to obtain the first mixed particles.

[0044] S2. Preparation of gold mine tailings particles: Same as in Example 1.

[0045] S3. Preparation of waste photovoltaic panel granules: Remove the aluminum frame and adhesive strips from the waste photovoltaic panels, then remove impurities adsorbed on the surface of the photovoltaic panels using high-pressure water. After natural drying, hammer the waste photovoltaic panels to a length <16cm and an area <320cm². 2 The blocks are placed into a jaw crusher. The jaw crusher is set with a feed size of ≤250mm and a discharge size of ≤10mm. The waste photovoltaic blocks are crushed into particles of ≤2mm to obtain waste photovoltaic panel particles for later use.

[0046] S4. Preparation of the second mixed particles: Steel slag and vanadium-titanium ore slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight, corresponding to steel slag and vanadium-titanium ore slag with a particle size ≤2mm. Then, steel slag and vanadium-titanium ore slag are placed in a planetary ball mill at a mass ratio of 1:1 and ball milled at a speed of 200r / min for 17min to obtain the second mixed particles with a particle size ≤2mm.

[0047] S5. Preparation of the third mixed particles: Aluminum ash slag and refining slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight to obtain aluminum ash slag and refining slag with particle size ≤2mm. Then, aluminum ash slag and refining slag are mixed in a planetary ball mill at a mass ratio of 3:2 to obtain the third mixed particles with a particle size ≤2mm.

[0048] S6. Preparation of low-carbon powder: Take the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles, and third mixed particles, mix them in a mass ratio of 71:12:6:8:3, and put them into a ball mill to grind the material to a specific surface area of ​​350m². 2 / kg, to obtain a mixed dry material, put the mixed dry material into a cement mortar mixer, and add water in two batches, each accounting for 9% of the mass of the mixed dry material. The first addition of 75% is mixed for 60 seconds, and the second addition of 25% is mixed for 120 seconds. The resulting mixture is placed in a mold, and the hydraulic press is set to a pressure of 15 MPa to press the mixture into pellets (pellet size Φ30mm × 20mm). The pellets are placed in an electric heating forced-air drying oven and dried at 100℃ for 20 minutes. The dried pellets are placed in a covered corundum crucible, and then the crucible is placed in a muffle furnace for high-temperature calcination. The high-temperature calcination regime in this embodiment is as follows: heating to 800℃ at a heating rate of 5℃ / min, holding for 20 minutes, heating to 1250℃ at a heating rate of 10℃ / min, and holding for 45 minutes. After calcination, the temperature was lowered to 1000℃ at a rate of 19℃ / min under a wind speed of 6 m / s, and then cooled to room temperature at a rate of 110℃ / min. The resulting high-temperature calcined product was crushed into ≤2mm particles in a jaw crusher, and then transferred to a cement ball mill at a speed of 48 r / min to grind the high-temperature calcined product to a specific surface area of ​​400~500 m². 2 / kg, to obtain low-carbon powder.

[0049] The chemical composition of the low-carbon powder in this embodiment is shown in Table 6: Table 6. Chemical composition of the low-carbon powder of Example 2

[0050] The activity index of the low-carbon powder in this embodiment is shown in Table 7: Table 7. Activity index of the low-carbon powder in Example 2

[0051] S7. Preparation of the second powder: Phosphogypsum and fluorogypsum are sieved separately using a vibrating screen to remove impurities. Then, they are placed in an electrically heated drying oven and dried at 105℃ to constant weight. The dried phosphogypsum and fluorogypsum are then mixed evenly at a mass ratio of 3:2 and placed in a cement ball mill, where they are ground at 48 r / min to a specific surface area of ​​350 m². 2 / kg, to obtain the second powder.

[0052] The second powder in this embodiment meets the technical specifications specified in GB / T 21371-2019 "Industrial By-product Gypsum for Cement". The second powder contains 87% CaSO4·2H2O and 87% CaSO4 (the specification requires ≥75%), 0.38% chloride ion content (the specification requires ≤0.5%), a pH value of 4.2 (the specification requires ≤5), and radioactive material limits that meet the requirements of GB 6566 (internal exposure index ≤1.0, external exposure index ≤1.0).

[0053] S8. Preparation of the third powder: The silicon-calcium slag and the alkali slag are screened to remove impurities, and the organic impurities are removed. Then, the silicon-calcium slag and the alkali slag are placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried silicon-calcium slag and alkali slag are mixed evenly at a mass ratio of 2:1 to obtain mixed slag powder. The mixed slag powder was placed in a cement mortar mixer and stirred for 6 minutes. During this time, water, accounting for 9% of the total dry mass, was added in two batches: 75% in the first batch and 25% in the second. After thorough mixing, the wet mixture was placed in a mold and pressed into a cake using a hydraulic press at a pressure of 15 MPa. The cake was 1.5 cm thick and 5 cm in diameter. The cake was then placed in an electric heating forced-air drying oven and dried at a constant temperature of 100°C for 32 minutes. The dried cake was then placed in a covered corundum crucible and calcined in a muffle furnace. The calcination process involved raising the temperature to 250°C at a rate of 5°C / min, holding for 25 minutes, and then raising the temperature to 800°C at a rate of 5°C / min and holding for 30 minutes. After calcination, the cake was cooled to room temperature at a rate of 19°C / min under a wind speed of 6 m / s. The cooled cake was then ground in a cement ball mill to a specific surface area of ​​400-500 m². 2 / kg, to obtain the third powder. The physicochemical properties of the third powder are shown in Table 8.

[0054] Table 8. Physicochemical properties of the third powder in Example 2

[0055] Note: In Table 8 1 The grade 1 refers to the technical specifications of "Quicklime for Silicate Building Products" JC / T 621-2021.

[0056] S9. Preparation of the fourth powder: The lithium tailings are screened to remove organic impurities and mud lumps. The screened lithium tailings are piled up in a cool place to dry, stirred twice a day, until the moisture content is 7%. Then, they are placed in an electric heating blast drying oven and dried at 105℃ to constant weight. Finally, they are put into a cement ball mill and ground to a specific surface area of ​​450m². 2 / kg, yielding the fourth powder. The technical specifications of this fourth powder are shown in Table 9. Table 9. Technical Specifications of the Fourth Powder in Example 2

[0057] Note: In Table 9 2 The grade 2 refers to the technical specifications of JC / T 622-2009, "Sand for Silicate Building Products".

[0058] S10. Molding and Curing: Take low-carbon powder, second powder, third powder and fourth powder, add them to the mixing tank in a mass ratio of 10:9:18:63, stir and mix well to obtain mixed powder. Add 60% of the total mass of the mixed powder with 52℃ warm water and 5‰ of the total amount of warm water as a foam stabilizer, stir for 90s, then add 0.6‰ of the total mass of the mixed powder with aluminum powder, stir for 50s to obtain a uniformly mixed slurry. During the stirring process, set up heat preservation measures to ensure that the temperature of the slurry when pouring into the mold is 47℃. Pour into the mold, then let it stand still for 4 hours to generate gas, and pre-cur at 63℃ for 4 hours. Cut the green body, then seal, vacuum, raise the temperature to 187℃ and the pressure to 1.20MPa, keep it at constant temperature and pressure for 7 hours, and then lower it to normal temperature and pressure to complete the high-temperature autoclaving curing to obtain the aerated concrete product.

[0059] The radioactivity test results of the mixed powder in step S10 of this embodiment are shown in Table 10: Table 10. Radioactivity test results of the mixed powder in step S10 of Example 2

[0060] Note: In Table 10 3 The number 3 in the remarks refers to the test index requirements in GB 6566-2010, "Limits of Radionuclides in Building Materials".

[0061] Example 3

[0062] The method for preparing aerated concrete for wall materials from lithium tailings, vanadium-titanium slag, and waste photovoltaic materials in this embodiment includes the following steps: S1. Preparation of the first mixed particles: The causticizing mud for papermaking is piled up and dried, stirred twice daily to achieve a moisture content of 25%. It is then placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried mud is then placed in a planetary ball mill and dispersed at 200 r / min for 20 minutes until particles with a diameter ≤2 mm are formed. Desulfurization ash is placed in a jaw crusher with a feed size ≤250 mm and a discharge size ≤10 mm. The desulfurization ash is crushed to 1-3 mm particles, then placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried desulfurization ash particles are then placed in a planetary ball mill and dispersed at 200 r / min for 20 minutes until particles with a diameter ≤2 mm are formed. The pretreated papermaking causticizing mud and desulfurization ash were added to a planetary ball mill at a mass ratio of 3:3 and ball-milled at a speed of 200 r / min for 20 min to obtain the first mixed particles.

[0063] S2. Preparation of gold mine tailings particles: Same as in Example 1.

[0064] S3. Preparation of waste photovoltaic panel granules: Remove the aluminum frame and adhesive strips from the waste photovoltaic panels, then remove impurities adsorbed on the surface of the photovoltaic panels using high-pressure water. After natural drying, hammer the waste photovoltaic panels to a length <20cm and an area <400cm². 2 The blocks are placed into a jaw crusher. The jaw crusher is set with a feed size of ≤250mm and a discharge size of ≤10mm. The waste photovoltaic blocks are crushed into particles of ≤2mm to obtain waste photovoltaic panel particles for later use.

[0065] S4. Preparation of the second mixed particles: Steel slag and vanadium-titanium ore slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight, corresponding to steel slag and vanadium-titanium ore slag with a particle size ≤2mm. Then, steel slag and vanadium-titanium ore slag are placed in a planetary ball mill at a mass ratio of 2:1 and ball milled at a speed of 200r / min for 20min to obtain the second mixed particles with a particle size ≤2mm.

[0066] S5. Preparation of the third mixed particles: Aluminum ash slag and refining slag are screened to separate particles ≤2mm and >2mm respectively. Then, the particles >2mm are crushed into ≤2mm particles in a jaw crusher and mixed with the ≤2mm particles obtained by screening. The mixture is then placed in an electric heating blast drying oven and dried at 105℃ to constant weight to obtain aluminum ash slag and refining slag with particle size ≤2mm. Then, aluminum ash slag and refining slag are mixed in a planetary ball mill at a mass ratio of 2:1 to obtain the third mixed particles with a particle size ≤2mm.

[0067] S6. Preparation of low-carbon powder: Take the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles, and third mixed particles, mix them in a mass ratio of 67:15:6:7:5, and put them into a ball mill to grind the material to a specific surface area of ​​400m². 2 / kg, to obtain a mixed dry material, put the mixed dry material into a cement mortar mixer, and add water in two batches, each accounting for 10% of the mass of the mixed dry material. The first addition of 75% water is mixed for 60 seconds, and the second addition of 25% water is mixed for 120 seconds. The resulting mixture is placed in a mold, and the hydraulic press is set to a pressure of 25 MPa to press the mixture into pellets (pellet size Φ30mm × 20mm). The pellets are placed in an electric heating forced-air drying oven and dried at 100℃ for 25 minutes. The dried pellets are placed in a covered corundum crucible, and then the crucible is placed in a muffle furnace for high-temperature calcination. The high-temperature calcination regime in this embodiment is as follows: heating to 800℃ at a heating rate of 5℃ / min, holding for 20 minutes, heating to 1300℃ at a heating rate of 10℃ / min, and holding for 60 minutes. After calcination, the temperature is lowered to 1000℃ at a rate of 20℃ / min under a wind speed of 8 m / s, and then cooled to room temperature at a rate of ≥100℃ / min. The resulting high-temperature calcined product is then crushed into particles ≤2mm in a jaw crusher, and then transferred to a cement ball mill at a speed of 48 r / min to grind the high-temperature calcined product to a specific surface area of ​​500 m². 2 / kg, to obtain low-carbon powder.

[0068] The chemical composition of the low-carbon powder in this embodiment is shown in Table 11: Table 11. Chemical composition of the low-carbon powder of Example 3

[0069] The activity index of the low-carbon powder in this embodiment is shown in Table 12: Table 12. Activity index of the low-carbon powder in Example 3

[0070] S7. Preparation of the second powder: Phosphogypsum and fluorogypsum are sieved separately using a vibrating screen to remove impurities. Then, they are placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried phosphogypsum and fluorogypsum are then mixed evenly at a mass ratio of 2:1 and placed in a cement ball mill, where they are ground at 48 r / min to a specific surface area of ​​400 m². 2 / kg, to obtain the second powder.

[0071] The second powder in this embodiment meets the technical specifications specified in GB / T 21371-2019 "Industrial By-product Gypsum for Cement". The second powder contains 80% CaSO4·2H2O and 80% CaSO4 (the specification requires ≥75%), 0.48% chloride ion content (the specification requires ≤0.5%), a pH value of 4.6 (the specification requires ≤5), and radioactive material limits that meet the requirements of GB 6566 (internal exposure index ≤1.0, external exposure index ≤1.0).

[0072] S8. Preparation of the third powder: The silicon-calcium slag and the alkali slag are screened to remove impurities, and the organic impurities are removed. Then, the silicon-calcium slag and the alkali slag are placed in an electric heating drying oven and dried at 105℃ to constant weight. The dried silicon-calcium slag and alkali slag are mixed evenly at a mass ratio of 3:1 to obtain mixed slag powder. The mixed slag powder was placed in a cement mortar mixer and stirred for 8 minutes. During this time, water, accounting for 10% of the total dry mass, was added in two batches: 75% in the first batch and 25% in the second. After thorough mixing, the wet mixture was placed in a mold and pressed into a cake with a thickness of 2 cm and a diameter of 6 cm using a hydraulic press at a pressure of 25 MPa. The cake was then placed in an electric heating forced-air drying oven and dried at a constant temperature of 100℃ for 40 minutes. The dried cake was then placed in a covered corundum crucible and calcined in a muffle furnace. The calcination process involved raising the temperature to 250℃ at a rate of 5℃ / min, holding for 30 minutes, and then raising it to 850℃ at a rate of 5℃ / min and holding for 35 minutes. After calcination, the cake was cooled to room temperature at a rate of 20℃ / min under a wind speed of 8 m / s. The cooled cake was then ground in a cement ball mill to a specific surface area of ​​500 m². 2 / kg, to obtain the third powder. The physicochemical properties of the third powder are shown in Table 13.

[0073] Table 13. Physicochemical properties of the third powder in Example 3

[0074] Note: In Table 13 1 The grade 1 refers to the technical specifications of "Quicklime for Silicate Building Products" JC / T 621-2021.

[0075] S9. Preparation of the fourth powder: The lithium tailings are screened to remove organic impurities and mud lumps. The screened and impurity-removed lithium tailings are piled up in a cool place to dry, stirred twice a day, until the moisture content is 10%. Then, they are placed in an electric heating blast drying oven and dried at 105℃ to constant weight. Finally, they are put into a cement ball mill and ground to a specific surface area of ​​500m². 2 / kg, yielding the fourth powder. The technical specifications of this fourth powder are shown in Table 14. Table 14. Technical Specifications of the Fourth Powder in Example 3

[0076] Note: In Table 14 2 The grade 2 refers to the technical specifications of JC / T 622-2009, "Sand for Silicate Building Products".

[0077] S10. Molding and Curing: Take low-carbon powder, second powder, third powder and fourth powder, add them to the mixing tank in a mass ratio of 11:7:21:61, stir and mix well to obtain mixed powder. Add 65% of the total mass of the mixed powder with warm water and 12‰ of the total mass of warm water with foam stabilizer, stir for 160s, then add 0.7‰ of the total mass of the mixed powder with aluminum powder, stir for 60s to obtain a uniformly mixed slurry. During the stirring process, set up heat preservation measures to ensure that the temperature of the slurry when pouring into the mold is 50℃. Pour into the mold, then let it stand still for 5 hours to generate gas, and pre-cur at 68℃ for 5 hours. Cut the green body, then seal, vacuum, raise the temperature to 195℃ and the pressure to 1.25MPa, keep it at constant temperature and pressure for 8 hours, and then lower it to normal temperature and pressure to complete the high-temperature autoclaving curing to obtain aerated concrete products.

[0078] The radioactivity test results of the mixed powder in step S10 of this embodiment are shown in Table 15: Table 15. Radioactivity test results of the mixed powder in step S10 of Example 3

[0079] Note: In Table 15 3 The number 3 in the remarks refers to the test index requirements in GB 6566-2010, "Limits of Radionuclides in Building Materials".

[0080] The properties of the aerated concrete products prepared in Examples 1-3 were tested, and the test results are shown in Table 16: Table 16. Performance indicators of aerated concrete products prepared in Examples 1-3

[0081] In Table 16, 4 The 4 in the index refers to the test index requirements in GB / T 11968-2020 "Autoclaved Aerated Concrete Blocks".

[0082] To further understand the performance of the aerated concrete of this application, the following tests were also conducted: (1) Mineral composition analysis of the high-temperature calcination products in the preparation of low-carbon powder Based on the low-carbon powder preparation steps in Example 2, three high-temperature calcination product samples were prepared. Specifically, the high-temperature calcination regime was set as follows: the temperature was increased to 800℃ at a heating rate of 5℃ / min and held for 20 min; then, the temperature was increased to 1250℃ at a heating rate of 10℃ / min and held for 40 min, 45 min, and 50 min, respectively, yielding the corresponding high-temperature calcination product samples M1, M2, and M3. The XRD patterns of samples M1, M2, and M3 are shown below. Figure 6 As shown.

[0083] Figure 6 XRD pattern analysis showed that the mineral composition of the high-temperature calcination products at different holding times consisted of dicalcium silicate (C2S), tricalcium silicate (C3S), calcium aluminoferrite (C4AF), tricalcium aluminate (C3A), and free calcium oxide (f-CaO). Samples M1, M2, and M3 were calcined at 1250℃. Sample M1 showed a relatively obvious f-CaO diffraction peak, but the f-CaO content decreased with increasing holding time. γ-C2S was detected in the high-temperature calcination products incorporating vanadium-titanium slag. Sample M1 had a relatively high γ-C2S content; however, with increasing holding time, the γ-C2S diffraction peaks disappeared in samples with holding times of 45 min and 50 min, while new β-C2S diffraction peaks appeared, indicating that prolonged holding time was beneficial for stabilizing β-C2S in the high-temperature calcination products.

[0084] The physical properties of the high-temperature calcined product (sample M2) with a holding time of 1250℃ for 45 min were tested, and the results are shown in Tables 7 and 17.

[0085] Table 17. Physicochemical properties of sample M2

[0086] As can be seen from Tables 7 and 17, the setting time and stability of sample M2 are both qualified, the flexural strength reaches 7.8 MPa after 28 days, and the compressive strength reaches 56.8 MPa, which shows excellent mechanical properties.

[0087] Mineral composition analysis was performed on the high-temperature calcination product (sample M2) held at 1250℃ for 45 min, and compared with ordinary clinker. The results are shown in Table 18.

[0088] Table 18. Quantitative analysis results of ordinary cement clinker and sample M2 composition (wt.%)

[0089] The data in Table 18 show that the mineral composition of the high-temperature calcined products prepared with all solid waste is basically the same as that of ordinary cement clinker. However, compared with ordinary clinker, the high-temperature calcined products prepared with all solid waste will reduce the content of C3S, C4AF, f-MgO, and K2SO4, while increasing the content of C2S, C3A, and CaTiO3.

[0090] (2) Microstructure of the high-temperature calcination product in the preparation of low-carbon powder The high-temperature calcination product (M2) from the preparation of low-carbon powder in Example 2 was used as a sample for scanning electron microscopy (SEM) analysis. The obtained SEM image is shown below. Figure 7 As shown, Figure 7In the image, (a) is a SEM image with a 500x lens, (b) is a SEM image with a 1500x lens, (c) is a SEM image with a 3000x lens, and (d) is a SEM image with a 5000x lens. From... Figure 7 It can be seen that the high-temperature calcined product has lower porosity and increased density in the low-magnification SEM images. This may be because the addition of vanadium-titanium slag to the high-temperature calcined product lowers the melting point and increases the amount of liquid phase and mesophase, resulting in higher density of the cooled product. High-magnification SEM images, combined with the previous quantitative analysis of sample M2, revealed the presence of large polyhedral C3S particles, smaller spherical granular C2S particles, and mesophases C3A and C4AF in the high-temperature calcined product, along with a small amount of periclase mineral phase in the shape of double tetrahedral octahedrons.

[0091] Energy dispersive spectroscopy (EDS) analysis was performed on the elemental composition and doping of the three mineral phases C3S, C2S, and the calcium aluminum iron (CAF) mesophase in M2. The results are as follows: Figure 8 As shown in Table 19.

[0092] Table 19. Mineral elemental composition analysis (%) in sample M2

[0093] Figure 8 Elemental energy dispersive spectroscopy (EDS) studies of silicate mineral phases revealed that, in addition to the main elements Ca, Si, and O, silicate minerals also contain trace amounts of other elements such as Na, Mg, Al, P, S, K, Ti, V, and Fe. Combined with Table 19, it was found that in the high-temperature calcination products with added vanadium-titanium ore slag, Ti and V elements were more likely to be incorporated into the CAF and C2S mineral phases, but not into the C3S phase.

[0094] (3) Analysis of phase composition and results of aerated concrete products in Example 2 X-ray diffraction was used to study lithium mine tailings and the aerated concrete product of Example 2, and the results are as follows: Figure 9 As shown, Figure 9 The black curve 1 represents lithium mine tailings, and the red curve 2 represents the aerated concrete product of Example 2. From... Figure 9 It can be seen that the main minerals in lithium mine tailings (curve 1) are quartz, microcline, and albite, which are high-quality siliceous raw materials for calcium silicate products. New phases, tobermorite, anhydrite, and calcite, appear in the aerated concrete products (curve 2) after high temperature and pressure treatment. The XRD diffraction peaks of the main mineral components in the original lithium mine tailings are weakened, indicating that under high temperature and pressure hydrothermal conditions, the [SiO4] in the lithium mine tailings...4- The breaking of Si-O bonds in the structure accelerates the dissolution of SiO2 in lithium tailings. The dissolved SiO2 reacts with Ca(OH)2 generated by cement hydration in a hydrothermal synthesis reaction, producing the corresponding hydration products CSH gel and tobermorite. The presence of calcite after autoclaving is likely due to carbonation products of the aerated concrete. Anhydrite is a residue of phosphogypsum and fluorogypsum in the system. The weakening of characteristic peaks for quartz, microcline, and albite in curve 2 indicates that these three minerals participated in the reaction. The remaining particles after the reaction, along with anhydrite and calcite, constitute the framework of the aerated concrete product, giving it sufficiently high strength. Simultaneously, the broad "convex hull" background below the 26°~34° diffraction peak in curve 2θ indicates the presence of amorphous (non-diffractive) amorphous and extremely low-crystallinity CSH gel in the green body.

[0095] Figure 10 These are comparative FT-IR spectra of the aerated concrete product sample and lithium tailings from Example 2. Figure 10 In the diagram, red curve 2 represents the aerated concrete product sample from Example 2, and black curve 1 represents lithium ore tailings. Figure 10 In the curve, all absorption peaks shift towards lower wavenumbers. In curve 1, the strongest absorption region is 900–1200 cm⁻¹. -1 This is a quartz absorption band, belonging to the Si-O asymmetric stretching vibration, consisting of a weak band from 1050 to 1200 cm⁻¹. -1 and a strong belt 900~1050cm -1 Its composition has a wide and strong absorption bandwidth, of which 993 cm⁻¹ is the largest. -1 The characteristic peak at this point is the asymmetric stretching vibration of Si-O, with a wavenumber of 770 cm⁻¹. -1 There is a moderately strong absorption peak at 687 cm⁻¹, belonging to the Si-O-Si symmetric stretching vibration, which is a characteristic peak of quartz group minerals. -1 460cm -1 and 418cm -1 The characteristic peak at this point is attributed to the bending vibration of Si-O. The wavenumber is at 3618 cm⁻¹. -1 3413cm -1 and 1630cm -1 The absorption band at this point is attributed to the bending vibration of OH groups in the crystallization water of quartz tailings. In curve 2, the wavenumber in the autoclaved aerated concrete is 3618 cm⁻¹. -1 3413cm -1 1088cm -1 993cm -1770cm -1 687cm -1 460cm -1 and 418cm -1 The characteristic peaks representing quartz group minerals disappeared, and new characteristic peaks appeared, with wavenumbers of 3420 cm⁻¹. -1 1632cm -1 1440cm -1 973cm -1 673cm -1 and 450cm -1 The wavenumber representing quartz in curve 2 is 777 cm⁻¹. -1 The characteristic spectral bands weaken. The number is at 3420 cm⁻¹. -1 and 1632cm -1 The absorption bands on the left and right represent the stretching vibrations of adsorbed water in the CSH gel, a hydration product; the wavenumber is around 1440 cm⁻¹. -1 The absorption band at that location is attributed to CO3 in calcite. 2- The asymmetric stretching vibration is caused by carbonation of aerated concrete; the wave number is 973 cm⁻¹. -1 The nearby absorption band is [SiO4]. 4- Q in the structure 2 This is caused by the symmetric stretching vibration of Si-O, and the characteristic peak absorption intensity at this position is very high, indicating that this vibration has strong infrared activity; the wavenumber is 450 cm⁻¹. -1 The nearby characteristic peaks are caused by the Si-O bending vibrations in the [SiO4] structure. The wavenumber is 977 cm⁻¹. -1 and 450cm -1 The characteristic peaks are all attributed to the layered structure of tobermorite.

[0096] Using the aerated concrete product from Example 2 as a sample, scanning electron microscopy (SEM) analysis was performed, and the resulting SEM images are shown below. Figure 11 As shown, Figure 11 In the image, (a) is a SEM image of the aerated concrete product under a 5-micron scanning microscope, and (b) is a hydration product image of region 2 in (a) under a 1-micron scanning microscope. Figure 12 yes Figure 11 (b) EDS spectrum of region 3. Figure 11 (a) The hydration product of area 1 marked in the diagram is a poorly crystalline and loosely structured CSH gel, which is consistent with... Figure 9 and Figure 10 The results are consistent with XRD and FT-IR analyses. Figure 11 (a) Enlarged version of the marked area 2 Figure 11(b) shows the formation of numerous highly crystalline, well-formed, plate-like tobermorite crystals, 1–2 μm wide and 60–80 nm thick. The plate-like tobermorite exhibits significantly increased crystallinity and interweaves with each other, forming the skeletal structure of the autoclaved aerated concrete (AAC) product, giving it sufficient strength. Simultaneously, cavities are formed between the plates, providing thermal insulation properties to the AAC product. After high-temperature autoclaving, the solubility of the active component SiO2 in the quartz tailings increases under alkaline hydrothermal conditions, enhancing its ability to participate in chemical reactions and playing a positive role in improving the crystallinity of the hydration products.

[0097] Figure 12 EDS analysis revealed the presence of Al in the hydration products. This is likely due to the addition of aluminum powder to the raw material system, which caused some [SiO4] tetrahedra to be replaced by [AlO4] tetrahedra. The hydration product in region 3 has an nCa / n(Si+Al) ratio of 0.8326, similar to tobermorite (Ca5(OH)2Si6O). 16 The composition of nCa / n(Si) = 0.8333 in ·4H2O is basically consistent.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing aerated concrete for wall materials from lithium tailings-vanadium-titanium mine slag-waste photovoltaics, characterized by, The method comprises the following steps: Preparation of first mixed particles, pretreatment of papermaking caustic white mud and desulfurization ash respectively, mixing of pretreated papermaking caustic white mud and desulfurization ash in a mass ratio of (1-3):(2-3) to obtain first mixed particles; Preparation of gold mine tailings particles, screening and crushing of gold mine tailings to a particle size of ≤2 mm, drying to constant weight to obtain gold mine tailings particles; Preparation of waste photovoltaic panel particles, cleaning and air-drying of waste photovoltaic panels, crushing to a particle size of ≤2 mm to obtain waste photovoltaic panel particles; Preparation of second mixed particles, screening and crushing of steel slag and vanadium-titanium ore slag to a particle size of ≤2 mm, drying to constant weight, mixing of dried steel slag and vanadium-titanium ore slag in a mass ratio of (1-2):(1-2) to obtain second mixed particles with a particle size of ≤2 mm; Preparation of third mixed particles, screening and crushing of aluminum ash and refining slag to a particle size of ≤2 mm, drying to constant weight, mixing of dried aluminum ash and refining slag in a mass ratio of (2-4):(1-3) to obtain third mixed particles with a particle size of ≤2 mm; The low-carbon powder is prepared by mixing the first mixed particles, gold mine tailing particles, waste photovoltaic panel particles, second mixed particles and third mixed particles, grinding to a specific surface area of 300-400 m 2 / kg, obtaining mixed dry materials, adding water accounting for 8-10% of the mass of the mixed dry materials, uniformly mixing, and then preparing pellets, drying, high-temperature calcining the dried pellets, two-stage cooling to room temperature, crushing the obtained calcined product to ≤2 mm particles, and grinding to a specific surface area of 400-500 m 2 / kg, obtaining low-carbon powder; The second powder material is prepared by removing impurities from phosphogypsum and fluorogypsum respectively, drying to constant weight, mixing the dried phosphogypsum and fluorogypsum according to a mass ratio of (2-4):(1-2), and grinding to a specific surface area of 300-400 m 2 / kg to obtain the second powder material; The third powder material is prepared by removing impurities from the silicon-calcium slag and the alkali slag respectively, drying to constant weight, mixing the dried silicon-calcium slag and the alkali slag according to a mass ratio of (1-3):1 to obtain a mixed slag powder, adding water in an amount of 8-10% of the mass of the mixed slag powder, uniformly mixing, forming a material cake, drying, calcining the dried material cake, and cooling and grinding to a specific surface area of 400-500 m 2 / kg to obtain the third powder material. A fourth powder is prepared. The lithium mine tailings are removed from impurities, dried to a moisture content of 3-10%, then dried to a constant weight, and ground to a specific surface area of 400-500 m 2 / kg to obtain a fourth powder; Molding and curing, mixing of low-carbon powder, second powder, third powder and fourth powder to obtain mixed powder, adding warm water and foam stabilizer and stirring, adding aluminum powder and stirring to obtain mixed slurry, pouring the mixed slurry into a mold at a mold temperature of 45-50℃, sequentially performing static standing and gas evolution, pre-curing, green body cutting, high-temperature autoclave curing to obtain aerated concrete products.

2. The method of claim 1, wherein, The pretreatment of the papermaking caustic white mud comprises: piling and air-drying the papermaking caustic white mud to a moisture content of 15-25%, then drying to constant weight, and then putting into a planetary ball mill to disperse to a particle size of ≤2 mm; The pretreatment of the desulfurization ash comprises: crushing the desulfurization ash to a particle size of 1-3 mm, then drying to constant weight, and then putting the dried desulfurization ash into a planetary ball mill to disperse to a particle size of ≤2 mm.

3. The method of claim 1, wherein, The mass ratio of the first mixed particles, gold mine tailings particles, waste photovoltaic panel particles, second mixed particles and third mixed particles is (60-77):(10-15):(5-10):(5-10):(3-5).

4. The method of claim 1, wherein, In the preparation of low-carbon powder, high-temperature calcination is performed at a temperature increasing rate of 5℃ / min to 800℃, holding for 20 min, and then increasing the temperature at a rate of 10℃ / min to 1200-1300℃, holding for 30-60 min.

5. The method of claim 1, wherein, The two-stage cooling to room temperature is performed at a wind speed of 5-8 m / s, at a rate of 18-20℃ / min to 1000℃, and then at a rate of ≥100℃ / min to room temperature.

6. The method of claim 1, wherein, In the preparation of third powder, the thickness of the cake is 1-2 cm, and the diameter is 4-6 cm, and the cake is placed in a constant temperature oven at 100℃ for 25-40 min.

7. The method of claim 1, wherein, In the preparation of third powder, the calcination conditions are as follows: increasing the temperature at a rate of 5℃ / min to 250℃, holding for 20-30 min, and then increasing the temperature at a rate of 5℃ / min to 750-850℃, holding for 25-35 min.

8. The method of claim 1, wherein, The mass ratio of the low-carbon powder, the second powder, the third powder and the fourth powder is (9-12):(6-10):(15-23):(55-70), the warm water is water with a temperature of 52-62 ℃, the total amount of the warm water is 55-65% of the mass of the mixed powder, the amount of the foam stabilizer is 5-12 ‰ of the total mass of the warm water, and the amount of the aluminum powder is 0.5-0.7 ‰ of the mass of the mixed powder.

9. The method of claim 1, wherein, The static gas generation and pre-curing time are both 3-5 h, and the pre-curing temperature is 55-68 ℃; the high-temperature autoclave curing process is: sealing, vacuumizing, heating to 180-195 ℃, pressure of 1.15-1.25 MPa, constant temperature and pressure for 6-8 h, and then reducing to normal temperature and pressure.

10. A lithium tailings-vanadium-titanium mine slag-waste photovoltaic preparation aerated concrete for wall materials, characterized in that, The method is prepared by using the method of any one of claims 1-9.

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