Ball-milling-free autoclaved aerated concrete based on gold tailing particle size grading and grading optimization and preparation method of ball-milling-free autoclaved aerated concrete
By constructing a synergistic particle size system and gradation optimization of fine and coarse gold tailings, combined with waste slurry activation, the problems of poor rheological properties and low strength of fine gold tailings in autoclaved aerated concrete were solved, achieving efficient and stable product production under ball mill-free process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-04-07
AI Technical Summary
In the existing technology, fine-grained gold tailings sand lacks skeleton particles, resulting in poor slurry rheology, unstable gas generation process, easy mold collapse and uneven pore distribution, and low product strength, which cannot meet the performance requirements of autoclaved aerated concrete for construction.
By constructing a synergistic particle size system of fine-grained and coarse-grained gold tailings, and by optimizing the gradation of waste slurry activation and siliceous by-products, dynamic equilibrium between reactive fine phase and skeleton support phase in the slurry is achieved, and autoclaved aerated concrete is prepared using a ball mill-free process.
Under ball mill-free conditions, the fluidity and pore uniformity of the slurry are guaranteed, the strength of the product is improved, the performance requirements of autoclaved aerated concrete for construction are met, and energy saving, carbon reduction and efficient utilization of fine-grained tailings are achieved.
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Figure CN121800501A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of green building materials and solid waste resource utilization technology, and in particular to a ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings sand and its preparation method. Background Technology
[0002] With the large-scale development and utilization of gold resources, ultrafine grinding technology has been widely adopted to improve gold leaching rates, leading to a year-on-year increase in the proportion of fine-grained gold tailings, which puts enormous pressure on environmental safety and land resources. Fine-grained gold tailings are mainly composed of SiO2, with a content of 60-80 wt%. Theoretically, they can be used as a siliceous raw material for autoclaved aerated concrete, realizing the resource utilization of solid waste.
[0003] Related technologies disclose methods for preparing autoclaved aerated concrete using gold tailings, but most still employ ball milling as a pretreatment process. For example, gold tailings are ground with water until the residue on a 0.08mm square-hole sieve is less than 25%. Ball milling not only increases energy consumption and cost but also limits the large-scale application of gold tailings.
[0004] Although fine-grained gold tailings sand has the characteristics of small particle size, large specific surface area and high reactivity, it has the following technical defects when used directly due to the lack of skeleton particles: First, the slurry has poor rheological properties and the diffusion degree is difficult to meet the casting requirements; second, the gas generation process is unstable and it is easy to cause problems such as mold collapse and uneven pore distribution; third, the product has low strength and cannot meet the performance requirements of autoclaved aerated concrete for building. Summary of the Invention
[0005] In view of this, the purpose of this invention is to provide a ball mill-free autoclaved aerated concrete and its preparation method based on the particle size classification and gradation optimization of gold tailings. This invention achieves a dynamic balance between the "reactive fine phase" and the "skeleton support phase" in the slurry by constructing a synergistic particle size system of fine and coarse gold tailings, and by optimizing the gradation of waste slurry activation and siliceous byproducts. This completely replaces the traditional ball milling process while ensuring the slurry's fluidity and porosity uniformity.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings sand, comprising the following components: matrix components and gas-generating components; The mass of the gas-generating component is 0.08~0.12% of the solid mass of the matrix component; The matrix components include the following components by mass percentage: 50-65% silica, 9-20% waste slurry, 18-25% calcium, and 3-8% calcium sulfate. The siliceous component comprises fine-grained gold tailings, coarse-grained gold tailings, and silicon industrial waste. The fine-grained and coarse-grained gold tailings are obtained from gold tailings through sequential grading and sieving. The sieve mesh size is 325 mesh. The fine-grained gold tailings are the portion below the 325 mesh sieve with a D50 of 8~15μm, and the coarse-grained gold tailings are the portion above the 325 mesh sieve with a D50 of 80~120μm. The mass percentage of fine-grained gold tailings in the siliceous component is 50~90%, the mass percentage of coarse-grained gold tailings is 10~30%, and the mass percentage of silicon industrial waste is 0~20% and not zero. The calcium-based components include lime and cement.
[0007] Preferably, the SiO2 content in the fine-grained gold tailings is 66~68wt%.
[0008] Preferably, the SiO2 content in the coarse-grained gold tailings is 68-70 wt%.
[0009] Preferably, the silicon industrial waste has a D50 of 40~80μm.
[0010] Preferably, the mass ratio of lime to cement is 1.2 to 1.75:1.
[0011] Preferably, the calcium sulfate-based substance includes desulfurized gypsum and / or phosphogypsum.
[0012] Preferably, the gas-generating component is a metal powder or metal compound that generates hydrogen gas in an alkaline environment.
[0013] Preferably, the ball mill-free autoclaved aerated concrete further includes admixtures, including water-reducing agents.
[0014] This invention also provides a method for preparing mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings sand as described in the above technical solution, comprising the following steps: The gold tailings were successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. The fine-grained gold tailings, waste slurry and water are activated to obtain activated fine sand slurry; The activated fine mortar, coarse-grained gold tailings, silicon industrial waste, and calcium sulfate-based substances are mixed to form an activated mortar. The activated mortar, calcium component and gas-generating component are mixed and then poured to obtain a green body; The green body is subjected to static curing, green body cutting and autoclaving in sequence to obtain the ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tail sand.
[0015] Preferably, the pressure of the autoclaving is 1.0~1.4MPa, the temperature is 180~210℃, and the constant temperature time is 6~10h; the temperature of the static curing is 40~60℃, and the time is 3~5h.
[0016] This invention provides a ball mill-free autoclaved aerated concrete based on gold tailings particle size classification and gradation optimization, comprising the following components: a matrix component and a gas-generating component; the mass of the gas-generating component is 0.08~0.12% of the solid mass of the matrix component; the matrix component comprises the following components by mass percentage: 50~65% siliceous component, 9~20% waste slurry, 18~25% calcareous component, and 3~8% calcium sulfate; the siliceous component comprises fine-grained gold tailings, coarse-grained gold tailings, and silicon industrial waste, wherein the fine-grained gold tailings and The coarse-grained gold tailings are obtained by classifying and sieving gold tailings sequentially. The sieve mesh size is 325 mesh. The fine-grained gold tailings are the portion below the 325 mesh sieve with a D50 of 8~15μm, and the coarse-grained gold tailings are the portion above the 325 mesh sieve with a D50 of 80~120μm. The siliceous component contains 50~90% fine-grained gold tailings by mass, 10~30% coarse-grained gold tailings by mass, and 0~20% silicon industrial waste by mass, which is not zero. The calcareous component includes lime and cement.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, fine-grained gold tailings play an active role in the hydration reaction; coarse-grained gold tailings and silicon industrial waste mainly serve as a skeletal support. After optimized combination, even under ball mill-free conditions, by adjusting the fine-to-coarse particle size distribution and water-to-material ratio, the workability of the slurry and the final strength of the product can be guaranteed. The calcareous components include lime and cement. The lime-cement dual-binder system has a synergistic cementing effect. The calcareous components are the main source of CaO in the hydrothermal reaction under autoclaving conditions. Both lime and cement can provide CaO, but their roles differ significantly during the setting and hardening of concrete. Cement hydrates prematurely during the static curing stage, generating CSH gel, which helps in the early formation of the slurry structure. Lime not only provides additional CaO for subsequent autoclaving but also significantly contributes to the exothermic reaction and maintains an alkaline environment, which is crucial for gas generation and early curing. The lime-cement dual-binder system produces a good synergistic effect, not only satisfying the gas generation and hardening of the green body but also enabling the product to exhibit better macroscopic properties. The ball mill-free autoclaved aerated concrete is suitable for producing autoclaved aerated concrete blocks and wall panels.
[0018] The present invention also provides a method for preparing mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings as described in the above technical solution. The preparation method of the present invention is simple to operate and suitable for industrial application.
[0019] Data from the embodiments show that the present invention has the following advantages: (1) Energy saving and carbon reduction: The ball mill-free process saves 30% of energy consumption and reduces carbon emissions by 20%; (2) High efficiency: The utilization rate of fine-grained tailings exceeds 50%, and the degree of solid waste resource utilization is high; (3) Performance improvement: The concrete's outlet strength is 3.6 MPa, oven-dry strength is 4.8 MPa, and dry density is 527 kg / m³. 3 It meets the requirements of B05 A3.5 superior grade; (4) Economic benefits: The cost is reduced by 15% to 20% after replacing natural sand, and it has industrial promotion value. Attached Figure Description
[0020] Figure 1 This is a flowchart illustrating the classification and screening process of gold tailings slurry according to the present invention. Figure 2 This is a flowchart of the preparation of ball mill-free autoclaved aerated concrete in Embodiment 1 of the present invention. Detailed Implementation
[0021] This invention provides a ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings sand, comprising the following components: matrix components and gas-generating components; The mass of the gas-generating component is 0.08~0.12% of the solid mass of the matrix component; The matrix components include the following components by mass percentage: 50-65% silica, 9-20% waste slurry, 18-25% calcium, and 3-8% calcium sulfate. The siliceous component comprises fine-grained gold tailings, coarse-grained gold tailings, and silicon industrial waste. The fine-grained and coarse-grained gold tailings are obtained from gold tailings through sequential grading and sieving. The sieve mesh size is 325 mesh. The fine-grained gold tailings are the portion below the 325 mesh sieve with a D50 of 8~15μm, and the coarse-grained gold tailings are the portion above the 325 mesh sieve with a D50 of 80~120μm. The mass percentage of fine-grained gold tailings in the siliceous component is 50~90%, the mass percentage of coarse-grained gold tailings is 10~30%, and the mass percentage of silicon industrial waste is 0~20% and not zero. The calcium-based components include lime and cement.
[0022] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field or are obtained using conventional technical means in the field.
[0023] In this invention, the mass of the gas-generating component can be 0.08%, 0.09%, 0.10%, or 0.12% of the solid mass of the matrix component. If the amount of the gas-generating component is too large, it will cause distortion of the gas-generating pores and reduce the gas-generating stability. If the amount is too small, it will cause the product to have an excessively high density.
[0024] In this invention, the gas-generating component is preferably a metal powder or metal compound that generates hydrogen in an alkaline environment, and more preferably includes aluminum.
[0025] In this invention, the aluminum is preferably used in the form of aluminum powder paste, the mass of the gas-generating component is based on aluminum, and the particle size of the aluminum powder in the aluminum powder paste is preferably 30~75μm.
[0026] In this invention, the slurry diffusion degree of the matrix component is preferably 30~37cm.
[0027] In this invention, the mass percentage of silicon component in the matrix component can be 50%, 55%, 58%, 59%, 60%, or 65%. If the amount of silicon component is too large, the calcium-silicon ratio will be too small, resulting in reduced product strength. If the amount is too small, the calcium-silicon ratio will be too large, resulting in reduced product strength.
[0028] In this invention, the mass percentage of fine-grained gold tailings in the siliceous component can be 45 / 58%, 47 / 60%, or 30 / 58%, the mass percentage of coarse-grained gold tailings can be 3 / 58%, 1 / 20%, or 9 / 29%, and the mass percentage of silicon industrial waste can be 5 / 29% or 1 / 6%. The fine-grained gold tailings mainly exert their activity and participate in the hydration reaction, while the coarse-grained gold tailings and silicon industrial waste mainly play a skeletal support role. After the three are optimized and combined, even under ball mill-free conditions, the workability of the slurry and the final strength of the product can be guaranteed.
[0029] In this invention, the volume ratio of fine-grained gold tailings to coarse-grained gold tailings is preferably 3:1 to 9:1, so that the diffusion degree of the resulting slurry is preferably 30 to 37 cm, so as to achieve a balance between the gas generation process and the thickening process under ball mill-free conditions.
[0030] In this invention, the SiO2 content in the fine-grained gold tailings is preferably 66-68 wt%, specifically 66 wt%, 67 wt%, or 68 wt%.
[0031] In this invention, the D50 of the fine-grained gold tailings can be 8, 8.4, 9, 10, 11, 12, 13, 14 or 15 μm, and D[4,3] is preferably 15~20 μm, specifically 15, 15.3, 16, 17, 18, 19 or 20 μm.
[0032] In this invention, the SiO2 content in the coarse-grained gold tailings is preferably 68-70 wt%, specifically 68 wt%, 69 wt%, or 70 wt%.
[0033] In this invention, the D50 of the coarse-grained gold tailings can be 80, 90, 100, 110, 111.2 or 120 μm, and D[4,3] is preferably 120~200 μm, specifically 120, 129.3, 140, 160, 180 or 200 μm.
[0034] In this invention, the D50 of the silicon industrial waste is preferably 40~80μm, specifically 40, 50, 60, 70, 77.4 or 80μm, and the D[4,3] is preferably 75~100μm, specifically 75, 86.3, 90 or 100μm.
[0035] In this invention, the SiO2 content in the silicon industrial waste is preferably not less than 70 wt%, more preferably 85-88 wt%, specifically 85 wt%, 86 wt%, 87 wt%, or 88 wt%.
[0036] In this invention, the silicon industrial waste is preferably an industrial by-product, and more preferably includes, but is not limited to, one or more of sodium silicate waste sand, quartz sand tailings and glass sand powder.
[0037] In this invention, the preferred mass ratio of the fine-grained gold tailings, silicon industrial waste, and coarse-grained gold tailings is 1:(0.1~0.25):(0.1~0.7), specifically 45:10:3, 47:10:3, or 30:10:18.
[0038] In this invention, the mass percentage of waste slurry in the matrix component can be 9%, 10%, 12%, 13%, 14%, 15%, or 20%, and the mass percentage of waste slurry is based on the solid matter in the waste slurry. The lime and cement give the waste slurry a higher pH value and more cementing components, thereby improving the activity and stability of the slurry.
[0039] In this invention, the waste slurry is preferably prepared by dispersing the scrap material generated during the cutting process of concrete billets with water, and is also referred to as cutting waste slurry. This invention does not impose any particular limitation on the specific method of dispersion; any method well-known to those skilled in the art can be used. In a specific embodiment of this invention, the waste slurry is preferably obtained from cutting the billet.
[0040] In this invention, the mass of the scrap material is preferably 10-15% of the mass of the blank, specifically 10%, 11%, 12%, 13%, 14% or 15%.
[0041] In this invention, the mass percentage of calcium component in the matrix component can be 18%, 20%, 22% or 25%. If the amount of calcium component is too large, it will lead to an excessive calcium-silicon ratio and increased cost. If the amount is too small, it will lead to an excessive calcium-silicon ratio and reduced product strength.
[0042] In this invention, the mass ratio of lime to cement is preferably 1.2 to 1.75:1, specifically 13:9, 1.2:1 or 1.75:1.
[0043] In this invention, the content of active calcium oxide in the lime is preferably 70-80%, specifically 70%, 75% or 80%.
[0044] In this invention, the mass percentage of calcium sulfate in the matrix component can be 3%, 5%, 6% or 8%. If the amount of calcium sulfate is too large, it will lead to a decrease in the strength of the product; if the amount is too small, it will lead to insufficient gas generation stability of the mortar.
[0045] In this invention, the calcium sulfate-based substances preferably include desulfurized gypsum and / or phosphogypsum.
[0046] In this invention, the ball mill-free autoclaved aerated concrete is preferably a concrete block or wall panel product.
[0047] In this invention, the ball mill-free autoclaved aerated concrete preferably further includes admixtures, which preferably include water-reducing agents.
[0048] In this invention, the mass of the additive can be 0.01%, 0.02%, 0.03%, or 0.08% of the solid mass in the matrix component. If the amount of the additive is too large, it will lead to excessive diffusion; if the amount is too small, it will lead to insufficient diffusion and reduced gas generation stability.
[0049] This invention also provides a method for preparing mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tailings sand as described in the above technical solution, comprising the following steps: The gold tailings were successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. The fine-grained gold tailings, waste slurry and water are activated to obtain activated fine sand slurry; The activated fine mortar, coarse-grained gold tailings, silicon industrial waste, and calcium sulfate-based substances are mixed to form an activated mortar. The activated mortar, calcium component and gas-generating component are mixed and then poured to obtain a green body; The green body is subjected to static curing, green body cutting and autoclaving in sequence to obtain the ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tail sand.
[0050] This invention involves classifying and sieving gold tailings sequentially to obtain fine-grained gold tailings and coarse-grained gold tailings.
[0051] The present invention preferably classifies and sieves the gold tailings slurry using a combined hydrocyclone and screen classification system, and obtains +325 mesh coarse-grained gold tailings and -325 mesh fine-grained gold tailings after dewatering.
[0052] Figure 1 This is a flowchart of the classification and screening process for gold tailings slurry in this invention. The gold mine beneficiation plant obtains gold tailings slurry through flotation of tailings. The gold tailings slurry is then classified by a hydrocyclone to obtain overflow and underflow. The overflow, which is the portion below a 325-mesh screen, is thickened and pressure filtered to obtain fine-grained gold tailings. The underflow, which is the portion above a 325-mesh screen, is filtered through a screen to obtain coarse and medium-grained particles. The coarse particles are dried to obtain coarse-grained gold tailings, and the medium-grained particles are magnetically separated to obtain medium-grained gold tailings. The water obtained during the pressure filtration, drying, and magnetic separation processes sequentially enters the hydrocyclone.
[0053] After obtaining fine-grained gold tailings, the present invention performs fine sand activation on the fine-grained gold tailings, waste slurry and water to obtain activated fine sand slurry.
[0054] In this invention, the mass ratio of the sum of the fine-grained gold tailings and waste slurry to water is preferably 1:0.30~0.45.
[0055] In this invention, the activation time of the fine sand is preferably 5-10 minutes. During the activation process, the fine-grained gold tailings and waste slurry are thoroughly mixed. Due to the large specific surface area of the fine-grained gold tailings, the reacted lime cement gives the waste slurry a high pH value, which is then converted into an OH- ion. - The erosion action destroys the inert oxide film on the surface of the tailings particles, and the premixing of the two helps to activate the fine sand and uniformly disperse the slurry.
[0056] After obtaining activated fine mortar and coarse-grained gold tailings, the present invention further prepares the activated fine mortar, coarse-grained gold tailings, silicon industrial waste, and calcium sulfate-based substances into a pulp to obtain activated mortar.
[0057] In this invention, the water-to-material ratio of the activated mortar is preferably 0.61 to 0.66, specifically 0.61, 0.62, 0.63, 0.64, 0.65, or 0.66. The diffusion degree is preferably 31 to 37 cm. According to the method provided by the China Autoclaved Aerated Concrete Association, the diffusion degree (flowability) of the AAC slurry is tested using a hollow steel barrel with an inner diameter of 50 mm and a height of 100 mm, specifically 31, 32, 33, 34, 34.5, 35, 36, or 37 cm.
[0058] This invention adds the coarse-grained gold tailings, silicon industrial waste, and calcium sulfate to activated fine mortar.
[0059] After obtaining the activated mortar, the present invention mixes the activated mortar, calcium component and gas-generating component and then pours them to obtain a green body.
[0060] In this invention, the calcium component is preferably added to the activated mortar and stirred with steam. After reaching a certain temperature (41~46℃), the gas-generating component and additives are added and stirred. Then, the mixture is poured into a mold car to obtain the blank.
[0061] In this invention, the preferred pouring temperature is 42~46℃, specifically 42, 43, 44, 44.5, 45 or 46℃. The pouring temperature can regulate the chemical reaction rate of the slurry, the foaming efficiency of the slurry, the coagulation and hardening process, the pore structure of the green body, the formation of the green body structure, and the strength and dry density of the finished product.
[0062] After obtaining the green body, the present invention sequentially performs static curing, green body cutting and autoclaving to obtain the ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tail sand.
[0063] In this invention, the preferred temperature for static curing is 40~60℃, specifically 40, 45, 50, 55 or 60℃, and the preferred time is 3~5h, specifically 3, 4, 4.5 or 5h. During the static curing process, the green body gasifies, forms, and hardens.
[0064] In this invention, it is preferable to cut the blank after achieving a cutting hardness of 0.1~0.2MPa.
[0065] In this invention, the pressure of the autoclaving is preferably 1.0~1.4MPa, specifically 1.1, 1.15, 1.2 or 1.3MPa, the temperature is preferably 180~210℃, specifically 190, 195, 196 or 200℃, and the constant temperature time is preferably 6~10h, specifically 6, 6.5, 7, 7.5 or 8h.
[0066] The particle size classification and gradation optimization principles proposed in this invention have reference value for other lightweight siliceous cementitious systems. The raw material system design principle of this invention is as follows: tailings are divided into fine and coarse particles according to particle size, and a balance between reactivity and skeletal support is achieved through ratio optimization; silicon industry waste is introduced to supplement the medium particle size range; activation and synergistic mechanism: the alkalinity and reactivity of the system are improved through waste slurry activation, achieving a synergistic structure of fine-particle active phase + coarse-particle skeletal phase; ball mill-free process path: relying on classification and optimization to replace mechanical grinding, and controlling the slurry rheology and porosity uniformity through process parameters; performance regulation principle: balancing fluidity and gas generation reaction rate, and coordinating the control of strength and dry density.
[0067] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0068] The raw materials used in the examples and comparative examples are as follows: The preparation processes for fine-grained and coarse-grained gold tailings are as follows: Figure 1 As shown, the gold tailings slurry was classified by particle size using a hydrocyclone and screen combined classification system. After preliminary dewatering, +325 mesh coarse-grained gold tailings and -325 mesh fine-grained gold tailings were obtained. The characteristics of the fine-grained gold tailings were: D50=8.4μm and D[4,3]=15.3μm in the undersize portion of the 325 mesh screen, and D50=111.2μm and D[4,3]=129.3μm in the oversize portion of the 325 mesh screen. The SiO2 content in the fine-grained gold tailings was 66wt%, and the SiO2 content in the coarse-grained gold tailings was 70wt%.
[0069] Characteristics of silicon industrial waste: D50=77.4μm, D[4,3]=86.3μm, and the SiO2 content in silicon industrial waste is 88wt%.
[0070] In the embodiments and comparative examples of this invention, the amounts of aluminum powder paste and polycarboxylate superplasticizer are based on the solid mass of the matrix components, the aluminum powder paste is calculated as aluminum powder, and the waste slurry is calculated as the solid mass of the waste slurry.
[0071] Example 1 The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 45% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 13% lime, and 9% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0072] Figure 2 The flowchart for preparing ball mill-free autoclaved aerated concrete in Embodiment 1 of the present invention includes the following steps: (1) The gold tailings are successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. (2) Fine sand activation: Fine-grained gold tailings and cutting waste slurry are mixed with water. The mass ratio of the sum of the fine-grained gold tailings and cutting waste slurry to the mass of water is 1:0.45. Activate for 10 min. Cutting waste slurry is made by mixing the scraps generated during the cutting process of the billet with water. The mass of the scraps is 10% of the mass of the billet. Activated fine sand slurry is obtained. (3) Stirring and slurry preparation: Coarse-grained gold tailings, silicon industrial waste and calcium sulfate are added to activated fine mortar and stirred to make activated mortar. The water-to-material ratio of the mortar is 0.64 and the diffusion degree is 33cm. (4) Batching and casting: Add lime and cement to the activated mortar and stir with steam. After reaching 42°C, add aluminum powder paste and polycarboxylate superplasticizer to complete the final mixing and pour into the mold car. The casting temperature is 44°C to obtain the green body. (5) Static curing: static curing temperature 50℃, static curing time 4.5h; (6) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (7) Autoclaving: Autoclaving pressure 1.2MPa, temperature 196℃, constant temperature time 7.5h.
[0073] Example 2 The preparation of ball mill-free autoclaved aerated concrete includes a matrix component and an air-generating component (aluminum powder paste). The matrix component includes the following components by mass percentage: 47% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 3% desulfurized gypsum, 13% lime, and 9% cement. The mass of the aluminum powder paste is 0.10% of the mass of the matrix component.
[0074] The preparation method includes the following steps: (1) The gold tailings are successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. (2) Fine sand activation: Fine-grained gold tailings and cutting waste slurry are mixed with water. The mass ratio of the sum of the fine-grained gold tailings and cutting waste slurry to the mass of water is 1:0.45. Activate for 10 min. Cutting waste slurry is made by mixing the scraps generated during the cutting process of the billet with water. The mass of the scraps is 10% of the mass of the billet. Activated fine sand slurry is obtained. (3) Stirring and slurry preparation: Coarse-grained gold tailings, silicon industrial waste and calcium sulfate are added to activated fine mortar and stirred to make activated mortar. The water-to-material ratio of the mortar is 0.64 and the diffusion degree is 32cm. (4) Batching and casting: Add lime and cement to the activated mortar and stir with steam. After reaching 43°C, add aluminum powder paste to complete the final stirring and pour into the mold car. The casting temperature is 44.5°C to obtain the billet. (5) Static curing: static curing temperature 50℃, static curing time 4.5h; (6) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (7) Autoclaving: Autoclaving pressure 1.2MPa, temperature 196℃, constant temperature time 7.5h.
[0075] Example 3 The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 45% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 13% lime, and 9% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0076] The preparation method includes the following steps: (1) The gold tailings are successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. (2) Fine sand activation: Fine-grained gold tailings and cutting waste slurry are mixed with water. The mass ratio of the sum of the fine-grained gold tailings and cutting waste slurry to the mass of water is 1:0.45. Activate for 10 min. Cutting waste slurry is made by mixing the scraps generated during the cutting process of the billet with water. The mass of the scraps is 10% of the mass of the billet. Activated fine sand slurry is obtained. (3) Stirring and slurry preparation: Coarse-grained gold tailings, silicon industrial waste and calcium sulfate are added to activated fine mortar and stirred to make activated mortar. The water-to-material ratio of the mortar is 0.65 and the diffusion degree is 34cm. (4) Batching and casting: Add lime and cement to the activated mortar and stir with steam. After reaching 40°C, add aluminum powder paste and polycarboxylate superplasticizer to complete the final mixing and pour into the mold car. The casting temperature is 42°C to obtain the green body. (5) Static curing: static curing temperature 50℃, static curing time 4.5h; (6) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (7) Autoclaving: Autoclaving pressure 1.2MPa, temperature 196℃, constant temperature time 8h.
[0077] Example 4 The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 30% fine-grained gold tailings, 18% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 13% lime, and 9% cement. The aluminum powder paste accounts for 0.09% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0078] The preparation method includes the following steps: (1) The gold tailings are successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. (2) Fine sand activation: Fine-grained gold tailings and cutting waste slurry are mixed with water. The mass ratio of the sum of the fine-grained gold tailings and cutting waste slurry to the mass of water is 1:0.45. Activate for 10 min. Cutting waste slurry is made by mixing the scraps generated during the cutting process of the billet with water. The mass of the scraps is 10% of the mass of the billet. Activated fine sand slurry is obtained. (3) Stirring and slurry preparation: Coarse-grained gold tailings, silicon industrial waste and calcium sulfate are added to activated fine mortar and stirred to make activated mortar. The water-to-material ratio of the mortar is 0.64 and the diffusion degree is 37cm. (4) Batching and casting: Add lime and cement to the activated mortar and stir with steam. After reaching 42°C, add aluminum powder paste and polycarboxylate superplasticizer to complete the final mixing and pour into the mold car. The casting temperature is 44°C to obtain the green body. (5) Static curing: static curing temperature 50℃, static curing time 4.5h; (6) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (7) Autoclaving: Autoclaving pressure 1.2MPa, temperature 195℃, constant temperature time 7.5h.
[0079] Example 5 The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 45% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 13% lime, and 9% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.03% of the matrix component mass.
[0080] The preparation method includes the following steps: (1) The gold tailings are successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. (2) Fine sand activation: Fine-grained gold tailings and cutting waste slurry are mixed with water. The mass ratio of the sum of the fine-grained gold tailings and cutting waste slurry to the mass of water is 1:0.45. Activate for 10 min. Cutting waste slurry is made by mixing the scraps generated during the cutting process of the billet with water. The mass of the scraps is 10% of the mass of the billet. Activated fine sand slurry is obtained. (3) Stirring and slurry preparation: Coarse-grained gold tailings, silicon industrial waste and calcium sulfate are added to activated fine mortar and stirred to make activated mortar. The water-to-material ratio of the mortar is 0.65 and the diffusion degree is 34.5cm. (4) Batching and casting: Add lime and cement to the activated mortar and stir with steam. After reaching 41°C, add aluminum powder paste and polycarboxylate superplasticizer to complete the final mixing and pour into the mold car. The casting temperature is 43°C to obtain the green body. (5) Static curing: static curing temperature 50℃, static curing time 4.5h; (6) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (7) Autoclaving: Autoclaving pressure 1.2MPa, temperature 195℃, constant temperature time 7.5h.
[0081] Comparative Example 1 (only coarse-grained gold tailings silica material was ball-milled) The raw material composition includes: 53wt% coarse-grained gold tailings, 7wt% sodium silicate waste sand, 15wt% waste slurry, 3wt% desulfurized gypsum, 7.5wt% lime, 14.5wt% cement, and aluminum powder paste accounting for 0.09% of the total solid mass. The total solids include the solids in coarse-grained gold tailings, sodium silicate waste sand, waste slurry, desulfurized gypsum, lime, and cement.
[0082] The preparation method includes the following steps: (1) Coarse-grained gold tailings, sodium silicate waste sand and desulfurized gypsum were wet-milled into slurry using a ball mill. The fineness of the slurry was controlled to have a residue of <25% on an 180-mesh sieve. Waste slurry was added to a cubic tank to obtain slurry. The slurry had the following properties: diffusion of 40 cm and water-to-material ratio of 0.61. Lime and cement were then added to the slurry and steam was introduced for stirring. After reaching 43°C, aluminum powder paste was added to complete the final stirring and poured into a mold car for casting. The casting temperature was 45°C to obtain the green body. (2) Static curing: static curing temperature 50℃, static curing time 4.5h; (3) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1MPa; (4) Autoclaving: Autoclaving pressure 1.20MPa, temperature 196℃, constant temperature time 7.5h.
[0083] Comparative Example 2 (only fine-grained gold tailings) The raw material composition includes: 60wt% fine-grained gold tailings, 15wt% waste slurry, 3wt% desulfurized gypsum, 13wt% lime, 9wt% cement, and aluminum powder paste accounting for 0.10% of the total solid mass. The total solids include the solids in the fine-grained gold tailings, waste slurry, desulfurized gypsum, lime, and cement.
[0084] The preparation method includes the following steps: (1) Fine-grained gold tailings, waste slurry, desulfurized gypsum and water are thoroughly mixed to make mortar. The mortar has the following properties: diffusion degree 29cm, water-material ratio 0.63. Then lime and cement are added to the mortar and steam is passed through for stirring. After reaching 42℃, aluminum powder paste is added to complete the final mixing and pouring into the mold car for pouring. The pouring temperature is 44℃ to obtain the green body. (2) Static curing: static curing temperature 50℃, static curing time 4.5h; (3) Blank cutting: Cutting is carried out after the cutting hardness reaches 0.1 MPa; (4) Autoclaving: Autoclaving pressure 1.20MPa, temperature 195℃, constant temperature time 7.5h.
[0085] Example 6 Same as Example 1, except that: The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 45% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 12% lime, and 10% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0086] Example 7 Same as Example 1, except that: The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 45% fine-grained gold tailings, 3% coarse-grained gold tailings, 10% sodium silicate waste sand, 15% waste slurry, 5% desulfurized gypsum, 14.0% lime, and 8.0% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0087] Example 8 Same as Example 1, except that: The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 49% fine-grained gold tailings, 5% coarse-grained gold tailings, 11% sodium silicate waste sand, 9% waste slurry, 4% desulfurized gypsum, 14.0% lime, and 8.0% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0088] Example 9 Same as Example 1, except that: The preparation of ball mill-free autoclaved aerated concrete includes a matrix component, an air-generating component (aluminum powder paste), and an admixture (polycarboxylate superplasticizer). The matrix component comprises the following components by mass percentage: 44% fine-grained gold tailings, 3% coarse-grained gold tailings, 8% sodium silicate waste sand, 14% waste slurry, 8% desulfurized gypsum, 15.0% lime, and 8.0% cement. The aluminum powder paste accounts for 0.10% of the matrix component mass, and the polycarboxylate superplasticizer accounts for 0.02% of the matrix component mass.
[0089] Table 1 compares the product performance of the embodiments and comparative examples. As shown in Table 1, the present invention eliminates the need for ball milling and significantly improves the strength of the product after drying. Furthermore, the ball-mill-free process of the present invention saves 30% of energy consumption, reduces carbon emissions by 20%, achieves a fine-grained tailings utilization rate of over 50%, and reduces costs by 15% to 20% after replacing natural sand, demonstrating its value for industrial-scale promotion.
[0090] Table 1. Comparison of product performance between the examples and comparative examples
[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A ball mill-free autoclaved aerated concrete based on gold tailings particle size classification and gradation optimization, characterized in that, It includes the following components: matrix components and gas-generating components; The mass of the gas-generating component is 0.08~0.12% of the solid mass of the matrix component; The matrix components include the following components by mass percentage: 50-65% silica, 9-20% waste slurry, 18-25% calcium, and 3-8% calcium sulfate. The siliceous component comprises fine-grained gold tailings, coarse-grained gold tailings, and silicon industrial waste. The fine-grained and coarse-grained gold tailings are obtained from gold tailings through sequential grading and sieving. The sieve mesh size is 325 mesh. The fine-grained gold tailings are the portion below the 325 mesh sieve with a D50 of 8~15μm, and the coarse-grained gold tailings are the portion above the 325 mesh sieve with a D50 of 80~120μm. The mass percentage of fine-grained gold tailings in the siliceous component is 50~90%, the mass percentage of coarse-grained gold tailings is 10~30%, and the mass percentage of silicon industrial waste is 0~20% and not zero. The calcium-based components include lime and cement.
2. The ball mill-free autoclaved aerated concrete according to claim 1, characterized in that, The SiO2 content in the fine-grained gold tailings is 66~68wt%.
3. The ball-mill-free autoclaved aerated concrete according to claim 1 or 2, characterized in that, The SiO2 content in the coarse-grained gold tailings is 68~70wt%.
4. The ball-mill-free autoclaved aerated concrete according to claim 1, characterized in that, The silicon industrial waste has a D50 of 40~80μm.
5. The ball mill-free autoclaved aerated concrete according to claim 1, characterized in that, The mass ratio of lime to cement is 1.2~1.75:
1.
6. The ball-mill-free autoclaved aerated concrete according to claim 1, characterized in that, The calcium sulfate substances include desulfurized gypsum and / or phosphogypsum.
7. The ball mill-free autoclaved aerated concrete according to claim 1, characterized in that, The gas-generating component is a metal powder or metal compound that produces hydrogen gas in an alkaline environment.
8. The ball-mill-free autoclaved aerated concrete according to claim 1, characterized in that, The ball mill-free autoclaved aerated concrete also includes admixtures, including water-reducing agents.
9. The method for preparing mill-free autoclaved aerated concrete based on particle size classification and gradation optimization of gold tailings sand according to any one of claims 1 to 8, characterized in that, Includes the following steps: The gold tailings were successively classified and screened to obtain fine-grained gold tailings and coarse-grained gold tailings. The fine-grained gold tailings, waste slurry and water are activated to obtain activated fine sand slurry; The activated fine mortar, coarse-grained gold tailings, silicon industrial waste, and calcium sulfate-based substances are mixed to form an activated mortar. The activated mortar, calcium component and gas-generating component are mixed and then poured to obtain a green body; The green body is subjected to static curing, green body cutting and autoclaving in sequence to obtain the ball mill-free autoclaved aerated concrete based on the particle size classification and gradation optimization of gold tail sand.
10. The preparation method according to claim 9, characterized in that, The autoclaving pressure is 1.0~1.4MPa, the temperature is 180~210℃, and the constant temperature time is 6~10h; The static curing temperature is 40~60℃, and the time is 3~5 hours.