Preparation method of aerated concrete based on lithium slag-waste photovoltaic panel-vanadium-titanium slag

Abstract

The invention relates to the technical field of comprehensive utilization of resources, in particular to a preparation method of aerated concrete based on lithium slag-waste photovoltaic panel-vanadium titanium slag. According to the preparation method, low-carbon powder prepared from steel solid waste, electric power industry solid waste, coal-based solid waste, nonferrous metallurgy solid waste and chemical solid waste is combined with mineral composition and content characteristics of the green low-carbon cement clinker, and replacement of the Portland cement clinker is achieved; chemical solid waste and non-metal mine solid waste are used for replacing all calcium raw materials, namely quick lime; the iron tailings are used as a high-silicon raw material to replace a silicon raw material, namely river sand or fly ash, in traditional production; the non-ferrous industry solid waste (lithium slag) and the electric power industry solid waste (desulfurized gypsum) are used as retarders to replace gypsum in traditional raw materials, through the synergistic effect of the four materials, the prepared autoclaved aerated concrete meets the standard requirement, the utilization rate of industrial solid waste is effectively increased, and the production cost of enterprises is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of resource comprehensive utilization, and particularly relates to a preparation method of aerated concrete based on lithium residue-waste photovoltaic panel-vanadium-titanium ore residue. BACKGROUND

[0002] The lithium residue refers to a residue obtained after a high-temperature reduction reaction, and the main components are metal elements such as silicon, iron and aluminum, and oxides and sulfides, and the lithium residue has characteristics such as high melting point, high hardness and stable chemical properties. In recent years, photovoltaic power generation has developed rapidly, and the waste photovoltaic panel produced simultaneously is also increasing. The waste photovoltaic panel contains glass, aluminum, adhesive sealant, silicon, silver, gallium, indium and other rare metals, and is extremely valuable for recycling. The vanadium-titanium ore residue refers to a granular or blocky industrial waste residue obtained by water quenching or natural cooling of high-temperature slag discharged in the smelting process of vanadium-titanium magnetite ore as raw material for smelting pig iron. 0.3-0.6 tons of waste residue can be discharged for every ton of iron smelted. The chemical composition of the vanadium-titanium ore residue is similar to that of ordinary blast furnace slag, mainly CaO, SiO2, Al2O3 and MgO, etc. The difference is that the TiO2 content is high, usually between 16% and 25%, which leads to the mineral composition of the vanadium-titanium ore residue mainly being crystal minerals such as titanic augite, anhydrous hard active perovskite, baiyeshi and spinel, and the amount of glassy components significantly decreases, and the activity is greatly reduced. Therefore, the utilization rate of the vanadium-titanium ore residue is very low at present.

[0003] The lithium residue, the waste photovoltaic panel and the vanadium-titanium ore residue are all common industrial solid wastes. If these industrial solid wastes cannot be reasonably utilized, not only will resources be wasted and land area be occupied, but also great pressure will be caused to the environment and ecological balance. SUMMARY

[0004] Therefore, the purpose of the application is to provide a preparation method of aerated concrete based on lithium residue-waste photovoltaic panel-vanadium-titanium ore residue, to replace the traditional raw materials of aerated concrete with various industrial solid wastes such as dicyandiamide waste residue, marble processing tailings, lead-zinc tailings, waste photovoltaic panel, copper residue, vanadium-titanium ore residue, coal gasification slag, coal slime, lithium residue, desulfurization gypsum and iron tailings, to prepare standard aerated concrete, effectively improve the utilization rate of industrial solid wastes and reduce the raw material cost of aerated concrete.

[0005] The application solves the above technical problems through the following technical means: In a first aspect, the application provides a preparation method of aerated concrete based on lithium residue-waste photovoltaic panel-vanadium-titanium ore residue, including the following steps: S1, dry dicyandiamide waste residue and marble processing tailings are uniformly mixed according to a mass ratio of (1-3):1, water is added and stirred, briquettes are prepared, dried, high-temperature calcined, cooled and ground to a specific surface area of 400-500 m 2 / kg, to obtain the first powder; S2, screen and crush the lead-zinc tailings into particles with a particle size ≤2mm, dry to constant weight, to obtain the first particles; S3, clean and dry the waste photovoltaic panels, crush and grind them to a specific surface area of ​​250~350m². 2 / kg, to obtain the second particle; S4, screen and crush the copper slag and vanadium-titanium ore slag into particles with a particle size ≤2mm, dry them to constant weight, and mix the dried copper slag and vanadium-titanium ore slag at a mass ratio of (1~2):1 to obtain the third particle; S5, screen and crush the coal gasification slag into particles with a particle size ≤2mm, dry them to constant weight, dry the coal slime to constant weight, and mix the dried coal gasification ash slag and coal slime at a mass ratio of 1:(2~4) to obtain the fourth particle; S6, mix the first powder, the first particle, the second particle, the third particle and the fourth particle, and grind the mixed dry material to a specific surface area of ​​400~500m². 2 / kg, add water and mix well, form into pellets, dry, calcine at high temperature, cool, crush, and grind to a specific surface area of ​​400~500m². 2 / kg, to obtain the second powder; S7, remove impurities from lithium slag and desulfurized gypsum, dry them separately to constant weight, mix the dried lithium slag and desulfurized gypsum in a mass ratio of (2~4):(1~2), and grind them to a specific surface area of ​​250~350m². 2 / kg, to obtain the third powder; S8, remove impurities from the iron tailings, dry to constant weight, and grind to a specific surface area of ​​400~500m². 2 / kg, to obtain the fourth powder; S9, take the first powder, the second powder, the third powder and the fourth powder and mix them evenly to obtain the mixed powder, add warm water, foam stabilizer and aluminum powder, mix evenly, pour into the mold at the mold temperature of 45~50℃, and cure to obtain aerated concrete.

[0006] Secondly, embodiments of this application also provide an aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag, which is prepared using the preparation method described in the first aspect above.

[0007] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: (1) The preparation method of the aerated concrete based on lithium slag-waste photovoltaic panel-vanadium titanium slag of the application, which uses 100% solid waste as raw material to prepare autoclaved aerated concrete, and the multi-source industrial solid waste used includes dicyandiamide waste slag, marble processing tailings, lead-zinc tailings, waste photovoltaic panel, copper slag, vanadium titanium slag, coal gasification slag, coal slime, lithium slag, desulfurization gypsum, and iron tailings, and the mechanical property index (strength), physical property index (density, thermal conductivity), and durability index (frost resistance) of the autoclaved aerated concrete prepared all meet the requirements in Autoclaved Aerated Concrete Block GB / T 11968-2020, effectively improving the utilization rate of industrial solid waste and significantly reducing the production cost of enterprises.

[0008] (2) The new aerated concrete proposed in the application uses industrial solid waste to replace the traditional autoclaved aerated concrete production raw materials - sand or fly ash, cement, lime, and gypsum, among which the low-carbon powder prepared from steel solid waste, power industry solid waste, coal-based solid waste, non-ferrous metallurgical solid waste, and chemical solid waste combines the mineral composition and content characteristics of green low-carbon cement clinker, realizing the replacement of Portland cement clinker; chemical solid waste and non-metallic mine solid waste are used to replace all calcareous raw materials - quicklime; iron tailings are used as high-silica raw materials to replace the traditional production of siliceous raw materials - river sand or fly ash; non-ferrous industry solid waste (lithium slag) and power industry solid waste (desulfurization gypsum) are used as retarders to replace traditional raw materials such as gypsum, and through the synergistic effect of the four, the slurry gas evolution and hardening speed are adjusted, the pore structure of the aerated concrete is optimized, the strength, dry density, and thermal insulation and sound insulation performance of the aerated concrete product are ensured, the composition of the autoclaved aerated concrete is more scientific and standardized, and it is more suitable for actual production process.

[0009] (3) The preparation method of the autoclaved aerated concrete proposed in the application uses the siliceous raw material iron tailings to meet the requirements of Silicate Building Products Sand JC / T 622-2009, replacing the demand for river sand and fly ash in traditional aerated concrete production, which can solve the problem of raw material shortage in some areas of aerated concrete production; the calcareous raw material prepared from dicyandiamide waste slag and marble processing tailings meets the technical index requirements of Silicate Building Products Quicklime (JC / T 621-2021), and the energy consumption of its firing temperature is reduced by more than 10% compared with the preparation of quicklime.

[0010] (4) The present application is designed and controlled by a specific crystal phase structure, so that the low-carbon powder (i.e. the second powder) made of the high-temperature calcined product is applied in the production of aerated concrete, which is significantly better than the existing ordinary Portland cement clinker, and the powder can be applied in the production of aerated concrete to achieve a high compressive strength of the aerated concrete body in a short time, promote the formation of the pore structure of the body, and provide protection for the compressive strength, dry density, thermal conductivity and other indicators of the finished aerated concrete; at the same time, the low-carbon powder has the good characteristics of low alkali, high early strength, low shrinkage, low carbon and low chloride ion content, which can shorten the construction period, and has important significance for road and bridge repair, building decoration, municipal engineering rush construction and repair, and as an emergency reserve technology in wartime.

[0011] (5) In the process of preparing the high-temperature calcined product in S6 step with calcareous materials (dicyandiamide waste slag, marble processing tailings), siliceous materials (lead-zinc tailings, waste photovoltaic panels), iron-aluminum materials (copper slag, vanadium-titanium ore slag, coal gasification slag, coal slime) as raw materials, the particle size, molding conditions, calcination time and holding time are reasonably controlled to form the best match, play a synergistic condition, so that the calcined product in S6 step forms a specific crystal phase structure, realizes its excellent early, middle and late performance, and can replace Portland cement clinker.

[0012] (6) The low-carbon powder (i.e. the second powder) prepared by the present application has a significant carbon reduction effect, and the firing temperature is reduced by more than 100 DEG C than Portland cement clinker, and the energy consumption is reduced by more than 10%, and the calcined product in S6 step uses all solid waste raw materials without using limestone, and the CO2 emission is reduced by more than 20%, which can significantly reduce the production cost of enterprises.

[0013] (7) The present application can purposefully and stably control the composition and content ratio of each mineral in the calcined product in S6 step, and the performance is excellent, which can reach and exceed the existing Portland cement clinker.

[0014] (8) The aerated concrete prepared by the preparation method of the present application has excellent mechanical performance indicators (compressive strength ≥ 4.40 MPa, far exceeding the current standard of compressive strength ≥ 4.40 MPa), bulk density (dry density ≤ 608 kg / m 3 , far lower than the current standard of dry density ≤ 650 kg / m 3The thermal conductivity (≤0.15, lower than the current standard of ≤0.16), frost resistance (strength loss after freezing and mass loss after freezing are ≤16.6% and ≤4.5% respectively, far lower than the current standard of ≤20% and ≤5.0%), and drying shrinkage (≤0.46mm / m, lower than the current standard limit of ≤0.50 mm / m) are all better than the test index requirements of A3.5 and B06 grade products in GB / T 11968-2020 "Autoclaved Aerated Concrete Blocks", and are better than existing products on the market. Attached Figure Description

[0015] Figure 1 This is the XRD pattern of dicyandiamide waste residue; Figure 2 This is the XRD pattern of lead-zinc tailings; Figure 3 This is the XRD pattern of coal gasification slag; Figure 4 This is the XRD pattern of coal slime; Figure 5 This is the XRD pattern of lithium slag; Figure 6 This is the XRD pattern of desulfurized gypsum; Figure 7 This is the XRD pattern of iron tailings; Figure 8 This is a graph showing the mortar strength test results of the second powder in Example 2; Figure 9 This is a graph showing the effect of iron tailings content on the performance of autoclaved aerated concrete in Example 2. Figure 10 This is a graph showing the effect of the foam stabilizer on the performance of autoclaved aerated concrete in Example 2; Figure 11 These are XRD patterns of the iron tailings aerated concrete product and the original iron tailings from Example 2. Figure 12 This is a FE-SEM image of the aerated concrete product after steam curing for 12 hours in Example 2; Figure 13 right Figure 12 (b) EDS spectra of regions A and B; Figure 14 This is a SEM image of the residual particles and surrounding reaction products in the autoclaved aerated concrete product of Example 2. Detailed Implementation

[0016] The following embodiments are provided to better understand the present invention and are not intended to limit the preferred embodiments. 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 scope of protection of the present invention. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in the art. Reagents or instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0017] The industrial solid waste used in the preparation of aerated concrete in this application includes the following: The dicyandiamide waste residue is mostly in the form of particles between 0.01 and 0.2 mm, in the form of gray paste and a small amount of sand, and mainly composed of calcium carbonate, carbon and cyanamide, and the XRD pattern thereof is shown in Figure 1 The mineral composition of the lead-zinc tailings is: quartz, calcium iron pyroxene, johannsenite, epidote and calcite, and the XRD pattern thereof is shown in Figure 2 The main mineral composition of the coal gasification slag is mullite, quartz and anorthite, and the XRD pattern thereof is shown in Figure 3 The main mineral composition of the coal slime is kaolinite, quartz, pyrite and dolomite, and the XRD pattern thereof is shown in Figure 4 The main mineral composition of the lithium slag is quartz, spodumene, anhydrite and the like, and the XRD pattern thereof is shown in Figure 5 The main mineral composition of the desulfurization gypsum is CaSO4·2H2O and CaSO4·1 / 2H2O, and the XRD pattern thereof is shown in Figure 6 The main mineral composition of the iron tailings is: quartz, sodium feldspar, hornblende, biotite, a small amount of chlorite, calcite and hematite, and the XRD pattern thereof is shown in Figure 7

[0018] The preparation method of the aerated concrete based on the lithium slag-waste photovoltaic panel-vanadium titanium slag according to the present application comprises the following steps: S1, the dicyandiamide waste residue and the marble processing tailings are respectively placed in an electric heating air drying oven and dried at 105℃ until constant weight, the dicyandiamide waste residue and the marble processing tailings after drying are mixed uniformly at a mass ratio of (1-3):1, then the mixed material is placed in a mortar mixer, 8-10% of the total mass of the dicyandiamide waste residue and the marble processing tailings is added in two times, 75% of the total mass of the water is added in the first time, and 25% of the total mass of the water is added in the second time, after uniform mixing, the mixed material is placed in a mold, the pressure of the hydraulic press is set to 15-25 Mpa, the mixed material is pressed into a ball (ball size Φ30mm ×20mm), the ball is placed in an electric heating air drying oven and dried at 100℃ for 15-25 min, the dried ball is calcined in a muffle furnace, the calcination system is: heating at a rate of 3℃ / min to 200℃, keeping for 20 min, then heating at a rate of 5℃ / min to 750-850℃, keeping for 30-40 min, after calcination, the ball is cooled by wind at a wind speed of 5-8 m / s at a speed of 18-20℃ / min, and then the cooled ball is ground in a cement ball mill to a specific surface area of 400-500 m 2 / kg to obtain a first powder.

[0019] ​S2, screen the lead-zinc tailings by using a vibrating screen to screen out impurities in the lead-zinc tailings, obtain >2mm and ≤2mm lead-zinc tailings particles after screening, then put the >2mm lead-zinc tailings particles into a jaw crusher to crush to ≤2mm particles, mix the ≤2mm lead-zinc tailings particles obtained by screening with the >2mm lead-zinc tailings particles, and then place them in an electric hot air drying oven to dry to constant weight at 105°C, to obtain lead-zinc tailings particles with a particle size of ≤2mm, i.e. the first particles.

[0020] S3, remove the attachments (aluminum frames and adhesive strips, etc.) of the waste photovoltaic panel, then use high-pressure water to remove impurities and dust adsorbed on the surface of the waste photovoltaic panel, and then use a hammer crusher to crush the waste photovoltaic panel to ≤25mm fragments, and then put the fragments into a cement ball mill, set the rotation speed of the cement ball mill to 48 r / min, and grind to a specific surface area of 250~350m 2 / kg, to obtain the second particles.

[0021] S4, screen the copper slag and vanadium-titanium slag into ≤2mm particles and >2mm particles respectively, then put the >2mm particles into a jaw crusher to crush to ≤2mm particles, mix the ≤2mm particles obtained by screening with the >2mm particles, and then place them in an electric hot air drying oven to dry to constant weight at 105°C, to obtain copper slag and vanadium-titanium slag with a particle size of ≤2mm, and then put the copper slag and vanadium-titanium slag into a planetary ball mill at a mass ratio of (1~2):1, set the rotation speed of the mill to 200 r / min, and ball mill for 15~20min, to obtain a ≤2mm particle mixture, i.e. the third particles.

[0022] S5, first screen the coal gasification slag into ≤2mm particles, >2mm particles and organic impurities, then put the >2mm particles into a jaw crusher to crush to ≤2mm particles, mix the ≤2mm particles obtained by screening with the >2mm particles, and then place them in an electric hot air drying oven to dry to constant weight at 105°C for use; place the coal slurry in an electric hot air drying oven to dry to constant weight at 105°C for use; and put the dried coal gasification slag and coal slurry into a planetary ball mill at a mass ratio of 1:(2~4) and mix uniformly, to obtain a ≤2mm particle mixture, i.e. the fourth particles.

[0023] S6, mix the first powder, the first particles, the second particles, the third particles and the fourth particles uniformly at a weight ratio of (60~77):(10~15):(5~10):(5~10):(3~5) to obtain a mixed dry material, and put the mixed dry material into a cement ball mill to grind to a specific surface area of 400~500m 2 / kg, then the ground material is put into a cement mortar mixer, 8-10% of the total dry material is added in two times, 75% of the total water is added in the first time, the cement mortar mixer is set to rotate at 140±5 r / min and revolve at 62±5 r / min for low-speed stirring for 50-80 s, 25% of the total water is added in the second time, the cement mortar mixer is set to rotate at 285±10 r / min and revolve at 125±10 r / min for high-speed stirring for 60-100 s, after uniform mixing, the mixture is put into a mold, and is pressed into a ball (ball size Φ30 mm × 20 mm) by a hydraulic press under a pressure of 15-25 MPa, the ball is placed in an electric heating air drying oven and is dried at 100℃ for 15-25 min. The dried ball is put into a covered corundum crucible, and the crucible is placed in a muffle furnace for high-temperature calcination, after calcination, the high-temperature calcination product is cooled to 1000℃ at a wind speed of 5-8 m / s and at a speed of 18-20℃ / min, and then is cooled to room temperature at a speed of not less than 100℃ / min. The high-temperature calcination system of this step is as follows: the temperature is raised to 300℃ at a rate of 3℃ / min, and is kept for 20-30 min, then the temperature is raised to 1150-1250℃ at a rate of 10℃ / min, and is kept for 30-40 min. The high-temperature calcination product is crushed to ≤2 mm particles by a jaw crusher, and then is put into a cement ball mill and is ground to a specific surface area of 400-500 m 2 / kg to obtain a second powder.

[0024] S7, the lithium slag and the desulfurization gypsum are screened by a vibrating screen respectively, and impurities are removed, then the lithium slag and the desulfurization gypsum are placed in an electric heating air drying oven and are dried at 105℃ to constant weight, then the dried lithium slag and the desulfurization gypsum are mixed uniformly according to a mass ratio of (2-4):(1-2), and are put into a cement ball mill and are ground to a specific surface area of 250-350 m 2 / kg to obtain a third powder.

[0025] S8, the iron tailings are screened, and organic impurities and mud blocks and other impurities are removed, then the iron tailings are placed in an electric heating air drying oven and are dried at 105℃ to constant weight, then the iron tailings are put into a cement ball mill and are ground to a specific surface area of 400-500 m 2 / kg to obtain a fourth powder. S9, the first powder, the second powder, the third powder and the fourth powder are added into a stirring tank according to a mass ratio of (15-23):(9-12):(6-10):(55-70), mixed uniformly to obtain a mixed powder, 50-55℃ warm water accounting for 52-64% of the total mass of the mixed powder is added, and a foam stabilizer accounting for 5-12‰ of the total amount of warm water is added, stirred for 90-120s, then aluminum powder accounting for 0.5-0.7‰ of the mass of the mixed powder is added and stirred for 30-50s to obtain a mixed slurry, a heat preservation measure is set during the stirring process to ensure that the mold temperature of the slurry when pouring is 45-50℃, the slurry is poured into a mold, and static standing and gas evolution are performed for 3-5h, pre-curing is performed at a temperature of 55-68℃ for 3-5h, then the green body is cut and high-temperature autoclaved to obtain the aerated concrete. The high-temperature autoclaving in this step is as follows: heating to 175-195℃ for 2-4h, saturated steam pressure is 1.0-1.25MPa, then constant temperature and pressure curing is performed for 8-10h, and natural cooling is performed. The foam stabilizer used in this step is prepared from 85-93wt% distilled water, 5-10wt% oleic acid and 2-5wt% sodium stearoyl lactylate. The aluminum powder has an active Al content of ≥91%, a 0.08mm square mesh sieve residue of ≤2.4%, a gas evolution rate of ≥82%, a gas evolution time of ≤23min and a hydrophilicity of ≤21s.

[0026] Specifically, the aerated concrete based on lithium slag-waste photovoltaic panel-vanadium titanium slag and the preparation method and performance detection results thereof of the present application will be described in detail by Examples 1-3: Example 1

[0027] The preparation method of the aerated concrete based on lithium slag-waste photovoltaic panel-vanadium titanium slag of the present application is as follows: S1, dicyandiamide waste slag and marble processing tailings are respectively placed in an electric heating air drying oven and dried at 105℃ until constant weight, the dried dicyandiamide waste slag and marble processing tailings are mixed uniformly according to a mass ratio of 1:1, then the mixed material is placed in a mortar stirrer, 8% of water accounting for the total mass of the dicyandiamide waste slag and marble processing tailings is added in two times, 75% of the total mass of the first added water is stirred uniformly, 25% of the total mass of the second added water is stirred uniformly, then the mixed material is placed in a mold, the pressure of a hydraulic press is set to 15Mpa, the mixed material is pressed into a ball (ball size Φ30mm × 20mm), the ball is placed in an electric heating air drying oven and dried at 100℃ for 15min, the dried ball is placed in a muffle furnace and calcined according to the following schedule: heating to 200℃ at a heating rate of 3℃ / min, keeping the temperature for 20min, then heating to 750℃ at a heating rate of 5℃ / min, keeping the temperature for 30min. After calcination, the ball is cooled by wind power at a speed of 6m / s at a rate of 18℃ / min, then the cooled ball is ground in a cement ball mill until the specific surface area is 400m2 / kg, to obtain the first powder.

[0028] The physicochemical properties of the first powder of the present example are shown in Table 1.

[0029] Table 1. Physicochemical properties of the first powder prepared in Example 1

[0030] In Table 1 1 The 1 in the grade is the technical index of “Quicklime for Silicate Building Products” JC / T 621-2021.

[0031] S2, screen the lead-zinc tailings by using a vibrating screen to remove impurities in the lead-zinc tailings, obtain >2 mm and ≤2 mm lead-zinc tailings particles after screening, then put the >2 mm lead-zinc tailings particles into a jaw crusher to crush to ≤2 mm particles, mix the ≤2 mm lead-zinc tailings particles obtained by vibrating screen screening with the >2 mm lead-zinc tailings particles, and then place them in an electric hot air drying oven at 105°C to dry to constant weight, to obtain lead-zinc tailings particles with a particle size of ≤2 mm, i.e. the first particles.

[0032] S3, remove the attachments (aluminum frames and adhesive strips, etc.) of the waste photovoltaic panels, then use high-pressure water to remove impurities and dust adsorbed on the surface of the waste photovoltaic panels, after natural air drying, use a hammer crusher to crush the waste photovoltaic panels to ≤25 mm fragments, then put the fragments into a cement ball mill, set the rotation speed of the cement ball mill to 48 r / min, and grind to a specific surface area of 250 m 2 / kg, to obtain the second particles.

[0033] S4, screen the copper slag and vanadium-titanium slag into ≤2 mm particles and >2 mm particles respectively, then put the >2 mm particles into a jaw crusher to crush to ≤2 mm particles, mix the ≤2 mm particles obtained by vibrating screen screening with the >2 mm particles, and then place them in an electric hot air drying oven at 105°C to dry to constant weight, to obtain copper slag and vanadium-titanium slag with a particle size of ≤2 mm, then put the copper slag and vanadium-titanium slag into a planetary ball mill at a mass ratio of 1:1, set the rotation speed of the mill to 200 r / min, and ball mill for 15 min, to obtain a mixture of ≤2 mm particles, i.e. the third particles.

[0034] S5, first, the coal gasification slag is screened into ≤2mm particles, >2mm particles and organic impurities, then the >2mm particles are put into a jaw crusher to be crushed into ≤2mm particles, and then the crushed particles are mixed with the ≤2mm particles obtained by screening, and then the mixture is placed in an electric hot air drying oven and dried at 105℃ until constant weight for standby use; the coal slime is placed in an electric hot air drying oven and dried at 105℃ until constant weight for standby use; the dried coal gasification slag and coal slime are put into a planetary ball mill in a mass ratio of 1:4 and mixed uniformly to obtain a mixture of ≤2mm particles, i.e. the fourth particles.

[0035] S6, the first powder, the first particles, the second particles, the third particles and the fourth particles are mixed uniformly in a weight ratio of 64:13:10:9:4 to obtain a mixed dry material, and the mixed dry material is put into a cement ball mill and ground at a rotation speed of 48 r / min until the specific surface area is 400m 2 / kg, then the ground material is put into a cement mortar stirrer, 8% of the mass of the mixed dry material is added in two times, 75% of the total mass of the first added water, the cement mortar stirrer is set to rotate at 140±5 r / min and revolve at 62±5 r / min for low-speed stirring for 50s, 25% of the total mass of the second added water, the cement mortar stirrer is set to rotate at 285±10 r / min and revolve at 125±10 r / min for high-speed stirring for 60s, after uniform stirring, the mixture is put into a mold, and a briquette (briquette size Φ30mm × 20mm) is pressed by a hydraulic press under a pressure of 15 MPa, and then the briquette is placed in an electric hot air drying oven and dried at 100℃ for 15min. The dried briquette is put into a covered corundum crucible, and then the crucible is placed in a muffle furnace for high-temperature calcination, after the calcination is completed, the high-temperature calcination product is cooled to 1000℃ at a wind speed of 6m / s and at a speed of 18℃ / min, and then cooled to room temperature at a speed of 100℃ / min, to obtain a high-temperature calcination product. The high-temperature calcination system of this step is: heating to 300℃ at a heating rate of 3℃ / min, keeping for 20min, and then heating to 1150℃ at a heating rate of 10℃ / min, keeping for 30min. The high-temperature calcination product is crushed into ≤2mm particles by a jaw crusher, and then put into a cement ball mill and ground at a rotation speed of 48 r / min until the specific surface area is 400m 2 / kg, to obtain the second powder.

[0036] The chemical composition of the second powder of this example is shown in Table 2.

[0037] Table 2. Chemical composition table of the second powder in Example 1

[0038] The activity index of the second powder of this example is shown in Table 3.

[0039] Table 3. Activity Index of the Second Powder in Example 1

[0040] S7. The lithium slag and desulfurized gypsum are screened 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 lithium slag and desulfurized gypsum 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 until a specific surface area of ​​250 m² is achieved. 2 / kg, to obtain the third powder.

[0041] The third powder in this embodiment meets the technical requirements specified in GB / T 21371-2019 "Industrial By-product Gypsum for Cement". The third powder contains 80% CaSO4·2H2O and 80% CaSO4 (the specification requires ≥75%), 0.43% 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).

[0042] S8. Screen the iron tailings to remove organic impurities and mud lumps, then place them in an electric heating drying oven and dry them at 105℃ to constant weight. Next, place them in a cement ball mill and grind them at 48 r / min to a specific surface area of ​​400 m². 2 / kg, yielding the fourth powder.

[0043] The technical specifications of the fourth powder in this embodiment are shown in Table 4.

[0044] Table 4. Technical Specifications of the Fourth Powder in Example 1

[0045] Table 4 2 The grade 2 refers to the technical specifications in JC / T 622-2009, "Sand for Silicate Building Products".

[0046] S9, the first powder, the second powder, the third powder and the fourth powder are added into the stirring tank according to the mass ratio of 20:10:8:62, mixed uniformly to obtain a mixed powder, 52℃ warm water accounting for 54% of the total mass of the mixed powder is added, and a foam stabilizer accounting for 7‰ of the total amount of warm water is added, stirred for 100s, then aluminum powder accounting for 0.5‰ of the mass of the mixed powder is added and stirred for 30s to obtain a uniformly mixed slurry, a heat preservation measure is set during the stirring process to ensure that the mold temperature of the slurry is 45℃ when pouring, and the slurry is poured into a mold, and static gas is generated for 3h, and pre-curing is carried out at a temperature of 58℃ for 3h, then the green body cutting is carried out, the temperature is raised to 175℃ at a time of 2h, the saturated steam pressure is 1.25MPa, then constant temperature and pressure curing is carried out for 10h, natural cooling is carried out, high temperature autoclaved curing is completed, and aerated concrete is obtained. The foam stabilizer in this step is prepared from 89.7wt% distilled water, 7.7wt% oleic acid and 2.6wt% sodium stearoyl lactylate.

[0047] The radioactivity test results of the mixed powder of this example are shown in Table 5.

[0048] Table 5. Radioactivity test results of the mixed powder in step S9 in Example 1

[0049] In Table 5, 3 3 in the note is the test index requirement in “Limit of Radionuclides in Building Materials” GB 6566-2010.

[0050] Example 2

[0051] The preparation method of the aerated concrete based on lithium slag-waste photovoltaic panel-vanadium titanium slag of this example is as follows: S1, dicyandiamide waste slag and marble processing tailings are respectively placed in an electric heating air drying oven and dried at 105℃ until constant weight, the dried dicyandiamide waste slag and marble processing tailings are mixed uniformly according to a mass ratio of 2:1, then the uniformly mixed materials are placed in a mortar stirrer, 9% of water accounting for the total mass of the dicyandiamide waste slag and marble processing tailings is added in two times, 75% of the total mass of the first added water is stirred, 25% of the total mass of the second added water is stirred, after the mixed materials are stirred uniformly, the mixed materials are placed in a mold, the pressure of the hydraulic press is set to 21Mpa, the mixed materials are pressed into pellets (pellet size Φ30mm × 20mm), the pellets are placed in an electric heating air drying oven and dried at 100℃ for 21min, the dried pellets are calcined in a muffle furnace, the calcination system is: heating to 200℃ at a heating rate of 3℃ / min, keeping the temperature for 20min, then heating to 800℃ at a heating rate of 5℃ / min, keeping the temperature for 35min. After calcination is completed, the pellets are cooled by wind power at a wind speed of 5m / s at a speed of 19℃ / min, then the cooled pellets are ground in a cement ball mill to a specific surface area of 450m2 / kg, to obtain the first powder.

[0052] The physicochemical properties of the first powder of this example are shown in Table 6.

[0053] Table 6. Physicochemical properties of the first powder prepared in Example 2

[0054] In Table 6 1 The 1 in the grade is the technical index of "Quicklime for Silicate Building Products" JC / T 621-2021.

[0055] S2, This step uses lead-zinc tailings to prepare the first particles, and the specific method is the same as in Example 1.

[0056] S3, This step uses waste photovoltaic panels to prepare the second particles with a surface area of 250 m 2 / kg, and the specific method is the same as in Example 1.

[0057] S4, Screen the copper slag and vanadium-titanium slag into particles ≤2 mm and particles >2 mm, respectively, and then crush the particles >2 mm to ≤2 mm particles in a jaw crusher, mix the crushed particles with the particles ≤2 mm screened by a vibrating screen, and place them in an electric hot air drying oven at 105°C to dry to constant weight. This corresponds to obtaining copper slag and vanadium-titanium slag with a particle size ≤2 mm. Then, put the copper slag and vanadium-titanium slag into a planetary ball mill at a mass ratio of 1.5:1, set the mill speed to 200 r / min, and ball mill for 15 min to obtain a mixture of particles ≤2 mm, i.e., the third particles.

[0058] S5, First, screen the coal gasification slag into particles ≤2 mm, particles >2 mm, and organic impurities, then crush the particles >2 mm to ≤2 mm particles in a jaw crusher, mix the crushed particles with the particles ≤2 mm screened, and place them in an electric hot air drying oven at 105°C to dry to constant weight; place the coal slurry in an electric hot air drying oven at 105°C to dry to constant weight; and mix the dried coal gasification slag and coal slurry in a planetary ball mill at a mass ratio of 1:3 to obtain a mixture of particles ≤2 mm, i.e., the fourth particles.

[0059] S6, Mix the first powder, the first particles, the second particles, the third particles, and the fourth particles uniformly at a weight ratio of 70:13:8:6:3 to obtain a mixed dry material, and put the mixed dry material into a cement ball mill to grind at a speed of 48 r / min to a specific surface area of 450 m 2 / kg, then the ground material is put into a cement mortar mixer, 9% of the total dry mixture is added twice, 75% of the total water is added first, the cement mortar mixer is set to rotate at 140±5 r / min and revolve at 62±5 r / min for low-speed stirring for 60 s, 25% of the total water is added second, the cement mortar mixer is set to rotate at 285±10 r / min and revolve at 125±10 r / min for high-speed stirring for 80 s, after uniform mixing, the mixture is put into a mold, and a hydraulic press is used to press the mixture into a ball (ball size Φ30 mm × 20 mm) under a pressure of 21 MPa, the ball is placed in an electric heating air drying oven and dried at 100 ℃ for 20 min. The dried ball is put into a covered corundum crucible, and the crucible is placed in a muffle furnace for high-temperature calcination, after calcination, the high-temperature calcination product is cooled to 1000 ℃ at a wind speed of 5 m / s and a cooling rate of 19 ℃ / min, and then cooled to room temperature at a cooling rate of 100 ℃ / min. The high-temperature calcination system of this step is as follows: the temperature is raised to 300 ℃ at a rate of 3 ℃ / min, and kept for 25 min, then the temperature is raised to 1200 ℃ at a rate of 10 ℃ / min, and kept for 35 min. The high-temperature calcination product is crushed to ≤2 mm particles with a jaw crusher, and then put into a cement ball mill to grind to a specific surface area of 450 m 2 / kg, to obtain a second powder.

[0060] The chemical composition of the second powder of this example is shown in Table 7.

[0061] Table 7. Chemical composition table of the second powder in Example 2

[0062] The activity index of the second powder of this example is shown in Table 8.

[0063] Table 8. Activity index table of the second powder in Example 2

[0064] An appropriate amount of gypsum is added to the second powder of this example, and mortar strength test is carried out with a water-cement ratio of 0.5 and a sand-cement ratio of 3. P·O 42.5 ordinary portland cement (hereinafter referred to as 42.5 cement) is used as a comparative sample, and mortar compressive strength test is carried out with the same water-cement ratio and sand-cement ratio. The compressive strength is measured at 1d, 3d, 7d, 28d and 90d ages, and the mortar strength of the second powder is shown in Table 9. Figure 8 The other physical property test results of the high-temperature calcination product in step S6 of this example are shown in Table 9.

[0065] Table 9. Physicochemical property test results of the high-temperature calcination product in step S6 of Example 2

[0066] From Figure 8 It can be seen from Table 9 that the compressive strengths of the cement cured for 1d, 3d, 7d, 28d and 90d of the second powder are all higher than that of the 42.5 cement. The 28d strength of the mortar specimen of the second powder is 3.8MPa different from that of the 42.5 cement, and the 90d compressive strength can exceed that of the 42.5 cement by 4.4MPa. The mechanical properties of the second powder depend on the optimized matching relationship of various minerals in the system, which can effectively ensure the optimal proportion of several minerals in the second powder, ensure the synergistic hydration between minerals, and promote the stable performance of the mechanical properties of the second powder. Further, the mechanical properties of the second powder are similar to or even better than those of the portland cement clinker, indicating that the second powder can replace the traditional portland cement clinker.

[0067] S7, screen the lithium slag and desulfurization gypsum respectively by using a vibrating screen to remove impurities, and then place them in an electric heat air drying oven at 105℃ to dry to constant weight. Then mix the dried lithium slag and desulfurization gypsum uniformly according to a mass ratio of 3:2, and then put them into a cement ball mill to grind at a speed of 48 r / min to a specific surface area of 300m 2 / kg, to obtain a third powder.

[0068] The third powder of the present embodiment meets the technical index requirements specified in GB / T 21371-2019 "Industrial By-product Gypsum for Use in Cement". The sum of CaSO4·2H2O and CaSO4 in the third powder is 83% (specification requires ≥75%), the chloride ion content is 0.46% (specification requires ≤0.5%), the pH value is 4.4 (specification requires ≤5), and the radioactive material limit value meets the requirements in GB 6566 (internal radiation index ≤1.0, external radiation index ≤1.0).

[0069] S8, a fourth powder with a specific surface area of 450m 2 / kg is prepared from the iron tailings as raw material, and the specific method is the same as in Example 1.

[0070] The technical index of the fourth powder of the present embodiment is shown in Table 10.

[0071] Table 10. Technical index table of the fourth powder in Example 2

[0072] The 2 2 in Table 10 is the technical index in "Sand for Silicate Building Products" JC / T 622-2009.

[0073] S9, the first powder, the second powder, the third powder and the fourth powder are added into the stirring tank according to the mass ratio of 17:11:6:66, mixed uniformly to obtain a mixed powder, 50 DEG C warm water accounting for 52% of the total mass of the mixed powder is added, and a foam stabilizer accounting for 9 ‰ of the total amount of warm water is added, stirred for 90 s, then aluminum powder accounting for 0.6 ‰ of the mass of the mixed powder is added and stirred for 40 s to obtain a uniformly mixed slurry, and a heat preservation measure is set during the stirring process to ensure that the mold temperature of the slurry when pouring is 47 DEG C, and the slurry is poured into a mold, and the slurry is statically stopped for 4 h to generate gas, and then the slurry is pre-cured at a temperature of 62 DEG C for 4 h, then the green body is cut, the temperature is raised to 182 DEG C at a time of 3 h, the saturated steam pressure is 1.18 MPa, then the temperature and pressure are kept constant for 9 h, and then the natural cooling is completed, and the autoclaved aerated concrete is obtained. The foam stabilizer in this step is prepared from 88.1 wt% distilled water, 8.8 wt% oleic acid and 3.1 wt% sodium stearoyl lactylate.

[0074] The radioactivity test results of the mixed powder in this embodiment are shown in Table 11.

[0075] Table 11. Radioactivity test results of the mixed powder in step S9 in Example 2

[0076] In Table 11, 3 Note 3 is the test index requirement in “Limit of Radionuclides in Building Materials” GB 6566-2010.

[0077] Figure 9 The physical and mechanical property test results of the autoclaved aerated concrete with different amounts of iron tailings under the condition of not adding a foam stabilizer are shown in Table 12, wherein (a) is the absolute dry density, and (b) is the compressive strength. From Figure 9 it can be seen that the absolute dry density of the autoclaved aerated concrete increases continuously with the increase of the amount of iron tailings, and when the amount of iron tailings is 70%, the absolute dry density of the autoclaved aerated concrete is the largest, reaching 589 kg·m -3 (see Figure 9 (a)); while the compressive strength of the aerated concrete increases first and then decreases with the increase of the amount of iron tailings, and when the amount of iron tailings is 66%, the compressive strength of the autoclaved aerated concrete reaches 4.91 MPa (see Figure 9 (b)), reaching the requirement for preparing autoclaved aerated concrete with river sand or fly ash, and its performance index far exceeds the test index requirement in “Autoclaved Aerated Concrete Block” GB / T 11968-2020.

[0078] Figure 10 is Figure 9 the macroscopic picture of the autoclaved aerated concrete with the amount of iron tailings being 66% and the foam stabilizer accounting for 9 ‰ of the total amount of water being added, Figure 10a is a diagram of the pore structure of the product without foam stabilizer. Figure 10 b is a diagram of the pore structure of the product with foam stabilizer, and Table 12 shows the results of the effect of foam stabilizer on the pore structure of aerated concrete. Figure 10 As shown in Table 12, without a foam stabilizer, the pores in the product are large and uneven, with some pores interconnected; after adding a foam stabilizer, the pores become smaller and the pore structure is more uniform, which is the reason for the difference in product strength. (Comparison) Figure 9 It can be seen that the oven-dry density of aerated concrete after adding foam stabilizer is higher than that of concrete with foam stabilizer. Figure 9 (a) The oven-dry density of the sample without foam stabilizer decreased by 0.51%, reaching 586 kg·m³. -3 The compressive strength increased by 2.24%, reaching 5.02 MPa (see...). Figure 9 (b) Since aerated concrete is a wall building material with a porous structure and a porosity of up to 70%, a large number of bubbles are generated in the slurry during the preparation of aerated concrete due to the reaction between Al powder and alkali. Whether these bubbles can exist stably and uniformly is a critical issue that directly affects the quality of the product.

[0079] As shown in Table 12, the porosity and the proportion of pores larger than 2 mm decreased in both aerated concrete products with and without foam stabilizers, while the proportion of pores smaller than 2 mm showed no significant change. In aerated concrete products without foam stabilizers, the difference in porosity and the proportion of pores larger than 2 mm between the upper and lower layers was larger, at 2.7% and 3.4% respectively. In products with foam stabilizers, the difference was larger, at 0.5% and 1.7% respectively, indicating a significant reduction in the difference between the upper and lower layers. This suggests that the addition of foam stabilizers to the slurry significantly improved the pore structure of the products. The experimental results also show that aerated concrete products using only Al powder for aeration have larger pores, more interconnected pores, and lower compressive strength. In contrast, aerated concrete products with foam stabilizers exhibited more stable foam. The foam stabilizer inhibited the merging of interconnected domains, increased the average sphericity of the foam, resulted in more uniform pore size, refined pore structure, and improved compressive strength.

[0080] Table 12. Effects of foam stabilizers on the pore structure of aerated concrete.

[0081] To investigate the composition of hydration products in autoclaved aerated concrete (AAC), X-ray diffraction was used to compare the phase composition of AAC products made from iron tailings and the original iron tailings. The test results are as follows: Figure 11 As shown, Figure 11 In the image, 1 represents the original iron tailings, and 2 represents aerated concrete products made from iron tailings. Through analysis of... Figure 11The comparative analysis can find that the maximum difference between autoclaved aerated concrete product and iron tailings atlas has four points: first, the characteristic peak of quartz in iron tailings is weakened, which shows that the internal quartz content of autoclaved aerated concrete product is reduced after autoclaving; second, the characteristic peaks of obvious hydration products tobermorite and hydrogarnet appear in the phase of autoclaved aerated concrete product; third, the characteristic peak of sodium feldspar in autoclaved aerated concrete product disappears after autoclaving; fourth, there is a wide “convex hull” background under the diffraction peak of 26 ~ 34 ° in the XRD atlas of autoclaved aerated concrete product.

[0082] Under the condition of hydrothermal synthesis, the calcareous and siliceous materials in the raw materials undergo a series of physical and chemical changes to generate autoclaved products, which are mainly composed of crystalline hydrated calcium silicate, tobermorite and other hydration phases, which determine the performance of autoclaved products. During the autoclaving process of aerated concrete, the continuously dissolved SiO2 in the siliceous raw material tailings reacts with Ca(OH)2 in the calcareous raw material to generate hydration products tobermorite and hydrogarnet, and the diffraction peak intensity of quartz in the phase of autoclaved aerated concrete after autoclaving decreases significantly, indicating that the quartz crystals in the iron tailings and Ca(OH)2 have undergone hydration reaction, and part of the residual quartz exists as aggregate in the aerated concrete. The diffraction peak of sodium feldspar in the autoclaved aerated concrete product disappears after autoclaving, indicating that the sodium feldspar in the iron tailings participates in the reaction after autoclaving, and the generation of hydration products hydrogarnet and tobermorite in the autoclaved aerated concrete product after autoclaving also proves that the single mineral sodium feldspar reacts under autoclaving test conditions, and the existence of hornblende and biotite phases in the grey sand brick verifies the reactivity of single minerals hornblende and biotite under autoclaving conditions. Figure 11 The wide “convex hull” background under the diffraction peak of 26 ~ 34 ° proves that there are amorphous substances or substances with low crystallinity (no diffraction peak) in the autoclaved aerated concrete product, which leads to the widening of the diffraction peak and affects the background value of the XRD diffraction spectrum.

[0083] Figure 12 FE-SEM of autoclaved aerated concrete product after autoclaving for 12h in this embodiment, wherein (a) is the hydration product graph at 5000 times, and (b) is the hydration product graph at 50000 times magnification of region 1 in (a). Figure 12As shown in Figure (a), a large number of hydration products appear inside the product after steam curing for 12 hours. The main hydration products in the field of view are thin-film tobermorite and poorly crystallized CSH gel. Scattered hydrogrossular garnets with similar spherical outlines are visible in between, and hydrogarnets are distributed in piles in some places. The tobermorite crystals and CSH gels are interwoven and tightly bonded, making the structure of the product dense and playing a positive role in improving the compressive strength of autoclaved lime-sand bricks. Figure (b) is an enlarged FE-SEM image of area 1 marked in Figure (a). A large number of highly crystalline plate-shaped tobermorite with a thickness of 0.1~0.3μm can be seen in the image. In the lower left corner of the image, hydrogrossular garnets with a botryoidal or spherical outline of about 0.3~0.5μm can be seen in small piles.

[0084] right Figure 12 (b) EDS spectrum analysis of regions A and B shows (see) Figure 13 , Figure 13 d is Figure 12 (b) EDS spectrum of region A, e is Figure 12 (b) EDS spectrum of region B), the autoclaving hydration products contain Al, mainly because the iron tailings contain Al, causing some [SiO4] tetrahedra to be replaced by [AlO4] tetrahedra. The autoclaving hydration products in region A... , with Tobermorite of The composition is basically the same. The autoclaving hydration products in region B... With hydrogrossular garnet of The composition is consistent.

[0085] Figure 14 SEM images of residual particles and surrounding reaction products in autoclaved aerated concrete (AAC) products. Figure 14 It is evident that the hydration product, tobermorite, adheres to the surface of the particles and is tightly connected to the cracks between the particles. Therefore, the bond between the hydration product and the particles is not easily broken when subjected to load.

[0086] Example 3 The preparation method of aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag in this embodiment is as follows: S1, the dicyandiamide waste residue, marble processing tailings were placed in an electric heat drying oven, dried to constant weight at 105℃, the dicyandiamide waste residue, marble processing tailings after drying were mixed uniformly according to the mass ratio of 3:1, then the mixed material was put into a mortar mixer, 10% of the total mass of dicyandiamide waste residue, marble processing tailings was added twice, 75% of the total mass of water was added the first time, and 25% of the total mass of water was added the second time, after mixing uniformly, the mixed material was placed in a mold, the pressure of the hydraulic press was set to 25Mpa, and the mixed material was pressed into a ball (ball size Φ30mm × 20mm), the ball was placed in an electric heat drying oven and dried at 100℃ for 25min, and the dried ball was placed in a muffle furnace for calcination, the calcination system was: heating at a rate of 3℃ / min to 200℃, holding for 20min, then heating at a rate of 5℃ / min to 850℃, holding for 40min. After calcination, the wind speed was 8m / s, and the cooling rate was 20℃ / min, then the cooled ball was put into a cement ball mill and ground to a specific surface area of 500m 2 / kg, to obtain a first powder.

[0087] The physicochemical properties of the first powder of the present embodiment are shown in Table 13.

[0088] Table 13. Physicochemical properties of the first powder prepared in Example 3

[0089] In Table 13 1 The 1 in the grade is the technical index of “Quicklime for Silicate Building Products” JC / T 621-2021.

[0090] S2, the first particle was prepared by using lead-zinc tailings, and the specific method was the same as that of Example 1.

[0091] S3, the second particle with a surface area of 350m 2 / kg was prepared by using waste photovoltaic panels, and the specific method was the same as that of Example 1.

[0092] S4, the copper residue and vanadium-titanium ore slag were sieved into ≤2mm particles and >2mm particles, respectively, then the >2mm particles were broken into ≤2mm particles in a jaw crusher, and then mixed with the ≤2mm particles obtained by sieving with a vibrating screen, and then placed in an electric heat drying oven and dried to constant weight at 105℃, to obtain copper residue and vanadium-titanium ore slag with a particle size of ≤2mm, then the copper residue and vanadium-titanium ore slag were placed in a planetary ball mill according to a mass ratio of 2:1, the mill speed was set to 200r / min, and the ball milling dispersion time was 20min, then the mixture was ball milled and mixed to obtain a third particle with a particle size of ≤2mm.

[0093] S5, first, the coal gasification slag is screened into ≤2 mm particles, >2 mm particles and organic impurities, then the >2 mm particles are put into a jaw crusher to be crushed into ≤2 mm particles, and then mixed with the ≤2 mm particles obtained by screening, and placed in an electric hot air drying oven to be dried at 105°C to constant weight for standby use; the coal slime is placed in an electric hot air drying oven to be dried at 105°C to constant weight for standby use; the dried coal gasification slag and coal slime are put into a planetary ball mill in a mass ratio of 1:2 to be mixed uniformly, and a fourth particle of ≤2 mm is obtained.

[0094] S6, the first powder, the first particle, the second particle, the third particle and the fourth particle are mixed uniformly in a weight ratio of 73:12:5:5:5 to obtain a mixed dry material, and the mixed dry material is put into a cement ball mill to be ground at a rotating speed of 48 r / min to a specific surface area of 500 m 2 / kg, then the ground material is put into a cement mortar stirrer, 10% of the total mass of the mixed dry material is added in two times, 75% of the total mass of the first added water is set at a self-rotation speed of 140±5 r / min and a public rotation speed of 62±5 r / min for low-speed stirring for 60 s, and 25% of the total mass of the second added water is set at a self-rotation speed of 285±10 r / min and a public rotation speed of 125±10 r / min for high-speed stirring for 80 s, and after uniform stirring, the mixed material is put into a mold and pressed into a ball (ball size Φ30mm × 20mm) by a hydraulic press at a pressure of 25MPa, and the ball is placed in an electric hot air drying oven to be dried at 100°C for 25 min. The dried ball is put into a covered corundum crucible, and the crucible is placed in a muffle furnace for high-temperature calcination, and after calcination, the product is cooled to 1000°C at a wind speed of 8m / s and a cooling rate of 20℃ / min, and then cooled to room temperature at a cooling rate of 105℃ / min, to obtain a high-temperature calcined product. The high-temperature calcination system of this step is: heating to 300°C at a heating rate of 3℃ / min, keeping for 30 min, and then heating to 1250°C at a heating rate of 10℃ / min, keeping for 40 min. The high-temperature calcined product is crushed into ≤2 mm particles by a jaw crusher, and then put into a cement ball mill to be ground at a rotating speed of 48 r / min to a specific surface area of 500 m 2 / kg, to obtain a second powder.

[0095] The chemical composition of the second powder of this example is shown in Table 14.

[0096] Table 14. Chemical composition table of the second powder in Example 3

[0097] The activity index of the second powder of this example is shown in Table 15.

[0098] Table 15. Activity Index of the Second Powder in Example 3

[0099] S7. The lithium slag and desulfurized gypsum are screened 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 lithium slag and desulfurized gypsum 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 until a specific surface area of ​​350 m² is achieved. 2 / kg, to obtain the third powder.

[0100] The third powder in this embodiment meets the technical requirements specified in GB / T 21371-2019 "Industrial By-product Gypsum for Cement". The third powder contains 79% CaSO4·2H2O and 79% CaSO4 (the specification requires ≥75%), 0.41% 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).

[0101] S8. This step uses iron tailings as raw material to prepare a material with a surface area of ​​500 m². 2 The fourth powder, at / kg, is prepared using the same method as in Example 1.

[0102] The technical specifications of the fourth powder in this embodiment are shown in Table 16.

[0103] Table 16. Technical Specifications of the Fourth Powder in Example 3

[0104] Table 16 2 The grade 2 refers to the technical specifications in JC / T 622-2009, "Sand for Silicate Building Products".

[0105] S9, the first powder, the second powder, the third powder and the fourth powder are added into the stirring tank according to the mass ratio of 15:9:8:68, mixed uniformly to obtain a mixed powder, 64% of the total mass of the mixed powder of 55°C warm water is added, and 12‰ of the total amount of warm water is added to the foam stabilizer, stirred for 120s, then 0.7‰ of the mass of the mixed powder is added to the aluminum powder and stirred for 50s to obtain a uniformly mixed slurry, the insulation measures are set during the stirring process to ensure that the mold temperature of the slurry is 50°C when pouring into the mold, pouring into the mold, static gas generation for 5h, pre-curing at a temperature of 68°C for 5h, then cutting the green body, heating to 195°C at a temperature of 4h, the saturated steam pressure is 1.0MPa, then constant temperature and pressure curing for 8h, natural cooling, high temperature autoclaved curing is completed, and the aerated concrete is obtained. The foam stabilizer in this step is prepared from 90.3wt% distilled water, 7.5wt% oleic acid and 2.2wt% sodium stearoyl lactylate.

[0106] The radioactivity test results of the mixed powder in this example are shown in Table 17.

[0107] Table 17. Radioactivity test results of the mixed powder in step S9 of Example 3

[0108] In Table 17, 3 Note 3 in the table is the test index requirement in "Limit of Radionuclides in Building Materials" GB 6566-2010.

[0109] The performance of the aerated concrete prepared in Examples 1-3 was detected, and the results are shown in Table 18.

[0110] Table 18. Performance test results of the aerated concrete of Examples 1-3

[0111] In Table 18, 4 4 in the index is the test index requirement in "Autoclaved Aerated Concrete Block" GB / T 11968-2020.

[0112] The above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the present application, which should be covered by the scope of the claims of the present application.

Claims

1. A method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag, characterized in that, Includes the following steps: S1. Mix the dried dicyandiamide waste residue and marble processing tailings at a mass ratio of (1~3):1, add water and mix well to form pellets, dry, calcine at high temperature, cool, and grind to a specific surface area of ​​400~500 m². 2 / kg, to obtain the first powder; S2. Screen and crush the lead-zinc tailings into particles with a diameter ≤2mm, and dry them to constant weight to obtain the first particle; S3. After cleaning and drying the waste photovoltaic panels, crush and grind them to a specific surface area of ​​250~350 m². 2 / kg, to obtain the second granule; S4. Screen and crush the copper slag and vanadium-titanium ore slag into particles with a particle size ≤2mm, dry them to constant weight, and mix the dried copper slag and vanadium-titanium ore slag at a mass ratio of (1~2):1 to obtain the third particle. S5. Screen and crush the coal gasification slag into particles with a particle size ≤ 2mm, dry them to constant weight, dry the coal slime to constant weight, and mix the dried coal gasification ash and coal slime at a mass ratio of 1: (2~4) to obtain the fourth particle. S6. Mix the first powder, the first particle, the second particle, the third particle, and the fourth particle thoroughly, and grind the resulting dry mixture to a specific surface area of ​​400-500 m². 2 / kg, add water and mix well, form into pellets, dry, calcine at high temperature, cool, crush, and grind to a specific surface area of ​​400~500m². 2 / kg, to obtain the second powder; S7. Remove impurities from the lithium slag and desulfurized gypsum, and dry them separately to constant weight. Mix the dried lithium slag and desulfurized gypsum at a mass ratio of (2~4):(1~2), and grind them to a specific surface area of ​​250~350m². 2 / kg, to obtain the third powder; S8. Remove impurities from the iron tailings, dry to constant weight, and grind to a specific surface area of ​​400~500 m². 2 / kg, yielding the fourth powder; S9. Take the first powder, the second powder, the third powder and the fourth powder and mix them evenly to obtain a mixed powder. Add warm water, foam stabilizer and aluminum powder, mix well, pour into the mold at the mold temperature of 45~50℃, and cure to obtain aerated concrete.

2. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 1, wherein, In step S1, the total amount of water used is 8-10% of the total mass of dicyandiamide waste residue and marble processing tailings. It is added in two parts. The first part adds 75% of the total mass of water, and after mixing, the second part adds the remaining 25% of water.

3. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 2, wherein, The high-temperature calcination in step S1 is as follows: the temperature is increased to 200°C at a heating rate of 3°C / min, held for 20 min, and then increased to 750~850°C at a heating rate of 5°C / min, held for 30~40 min.

4. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 1, wherein, In step S6, the mass ratio of the first powder, the first particle, the second particle, the third particle, and the fourth particle is (60~77):(10~15):(5~10):(5~10):(3~5). The total amount of water used is 8~10% of the mass of the mixed dry material, and it is added in two parts. The first part adds 75% of the total mass of water and mixes it well. The second part adds 25% of the total mass of water.

5. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 4, wherein, The high-temperature calcination in step S6 is as follows: the temperature is increased to 300°C at a heating rate of 3°C / min, held for 20-30 minutes, and then increased to 1150-1250°C at a heating rate of 10°C / min, held for 30-40 minutes.

6. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 1, wherein, In step S9, the mass ratio of the first powder, the second powder, the third powder, and the fourth powder is (15~23):(9~12):(6~10):(55~70); the total amount of warm water used is 52~64% of the mass of the mixed powder, and the warm water is water at 50~55℃.

7. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 6, wherein, The foam stabilizer is used at a dosage of 5-12‰ of the total mass of warm water, and is prepared by 85-93wt% distilled water, 5-10wt% oleic acid and 2-5wt% sodium stearoyl lactylate.

8. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 6, wherein, The amount of aluminum powder used is 0.5~0.7‰ of the mixed powder.

9. The method for preparing aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag according to claim 1, wherein, The curing process in step S9 is as follows: static gas generation is stopped for 3-5 hours, pre-curing is carried out at a temperature of 55-68℃ for 3-5 hours, followed by cutting of the billet and high-temperature autoclaving. The high-temperature steam curing process involves raising the temperature to 175-195℃ over 2-4 hours, with a saturated steam pressure of 1.0-1.25MPa, followed by constant temperature and pressure curing for 8-10 hours, and then allowing it to cool naturally.

10. An aerated concrete based on lithium slag-waste photovoltaic panels-vanadium-titanium slag, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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