Pseudo-ginseng lime soil and preparation method thereof

Abstract

The invention relates to the technical field of building materials, in particular to pseudo-ginseng lime soil and a preparation method thereof. Comprising the following components in parts by mass: 8-10 parts of gypsum powder, 15-20 parts of quicklime powder and 70-77 parts of first-class soil, the water content of the first-class soil is less than 5%. By accurately controlling the ratio of gypsum powder, quicklime powder and first-class soil and preparation process parameters, replacing traditional raw materials with industrial waste residues and combining a multi-stage fine treatment process, the defects that traditional lime soil is high in cost, unstable in performance and low in resource utilization rate are overcome; the method has the comprehensive advantages that the material performance stability is improved, the production cost is reduced, and industrial by-products are recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, in particular to a kind of Panax notoginseng ash soil and a preparation method of the Panax notoginseng ash soil. Background Art

[0002] The existing Sanqi lime soil is a kind of building material with high strength made by mixing lime and clay in a certain proportion. It has been widely and long-standingly used in the history of Chinese architecture. The physical, mechanical and chemical properties of Sanqi lime soil are determined by two basic components: clay and lime. The existing technology has the problem of excessive use of quicklime, which leads to increased costs, and there is room for optimization in key performance indicators such as optimal moisture content, maximum dry density and extrusion strength. In conventional technical solutions, the ratio system of quicklime and soil does not fully consider the synergistic effect between materials, and it is difficult to balance the relationship between cost and performance. That is, the existing Sanqi lime soil has the defects and shortcomings of high cost, but the key performance indicators such as optimal moisture content, maximum dry density and extrusion strength are generally poor.

[0003] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0004] The purpose of this application is to provide a Panax notoginseng ash soil and a preparation method thereof, which has the advantages of reducing costs, improving the stability of physical and mechanical properties, optimizing raw material quality control and realizing resource utilization of industrial waste residues.

[0005] This application provides a kind of Panax notoginseng ash soil, and the technical solution is as follows:

[0006] A Panax notoginseng ash soil, characterized by comprising the following components:

[0007] 8-10 parts by mass of gypsum powder, 15-20 parts by mass of quicklime powder, and 70-77 parts by mass of Class I soil; the moisture content of Class I soil is less than 5%.

[0008] Furthermore, the present application also proposes that the gypsum powder includes 30-38 parts by mass of alkali residue and 62-70 parts by mass of water.

[0009] Furthermore, the present application also proposes that quicklime powder is prepared from high-calcium stone with a calcium content of more than 48%.

[0010] Furthermore, the present application also proposes a method for preparing Panax notoginseng ash soil, which is characterized by comprising the following steps:

[0011] Step 1: Prepare gypsum powder:

[0012] S1: Take 30-38 parts by mass of alkali residue and 62-70 parts by mass of water, and mix them in a scrubbing machine to form a slurry;

[0013] S2: removing iron from the slurry in S1 in an iron remover to obtain wet slurry;

[0014] S3: In an environment of 15-40°C, take 10-30 parts by mass of the wet slurry and dilute it with 70-90 parts by mass of water, add 3kg / t of ammonium sulfate and 1kg / t of oxalic acid according to the weight ratio, and let it stand for 1-2 hours to react to obtain an alkaline slurry;

[0015] S4: dehydrating the alkaline slurry in S3 in a filter press to obtain a block-shaped slurry with a water content of less than 10%;

[0016] S5: crushing the blocky clay material in S4 in a crusher to obtain granular clay material;

[0017] S6: calcining the granular mud material in S5, and then naturally cooling it to below 40°C to obtain a gypsum semi-finished product;

[0018] S7: Grind the semi-finished gypsum product in S6 in a Raymond mill to obtain 200-mesh gypsum powder;

[0019] Step 2: Prepare quicklime powder:

[0020] S8: calcining high-calcium stone with a calcium content of more than 48%, and then naturally cooling it to below 40° C. to obtain a semi-finished lime product;

[0021] S9: Grind the lime semi-finished product in S8 in a Raymond mill to obtain 200-mesh quicklime powder;

[0022] Step 3: Prepare the Sanqi ash soil:

[0023] S10: Take 8-10 parts by mass of the gypsum powder obtained in step 1, take 15-20 parts by mass of the quicklime powder obtained in step 2, and take 70-77 parts by mass of a type of soil with a moisture content of less than 5%, and mix them evenly in a blender to obtain Panax notoginseng ash soil.

[0024] Furthermore, the present application also proposes that the alkali residue in step S2 refers to waste residue with calcium carbonate, calcium sulfate and calcium chloride as main components.

[0025] Furthermore, the present application also proposes that the magnetic field strength of the iron remover in step S2 is not less than 5000 GS.

[0026] Furthermore, the present application also proposes that the iron content of the wet slurry in step S2 is lower than 60 ppm.

[0027] Furthermore, the present application also proposes that the particle size of the granular mud material in step S5 is 0.5 to 1 cm.

[0028] Furthermore, the present application also proposes that in step S6, the calcination temperature is 800±5° C. and the calcination time is 30-45 minutes.

[0029] Furthermore, the present application also proposes that in step S8, the calcination temperature is 1000° C.-1050° C. and the calcination time is 60-85 minutes.

[0030] The present application provides a Panax notoginseng ash soil and a preparation method thereof, which solves the defects of high cost, unstable performance and low resource utilization of traditional ash soil by precisely controlling the ratio of gypsum powder, quicklime powder and Class I soil and the preparation process parameters, using industrial waste slag instead of traditional raw materials, and combining a multi-stage refined treatment process. It has the comprehensive advantages of improving the stability of material performance, reducing production costs and realizing the recycling of industrial by-products. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is described below with reference to embodiments.

[0032] In existing technologies, Sanqi lime soil, a traditional building material, is primarily composed of lime and clay in a proportional volume ratio. Excessive use of quicklime in existing technologies leads to increased costs, and key performance indicators such as optimal moisture content, maximum dry density, and compressive strength require optimization. Conventional solutions fail to fully consider the synergistic effects between the quicklime and soil, making it difficult to strike a balance between cost and performance.

[0033] To address these issues, research has shown that the amount of quicklime used directly impacts material cost and volume stability, while simply reducing the lime content can lead to insufficient strength. Analysis has revealed that gypsum reacts with alkaline substances to form a cementitious product, potentially replacing some of the lime required. Repeated experiments have confirmed that achieving a specific ratio of gypsum powder to quicklime maintains alkaline activation conditions while reducing lime usage. Furthermore, controlling the soil's moisture content has been shown to optimize the hydration reaction and improve material density.

[0034] Therefore, this application proposes a Panax notoginseng ash soil material system including gypsum powder, quicklime powder and Class I soil, wherein gypsum powder accounts for 8-10 parts by mass, quicklime powder accounts for 15-20 parts by mass, Class I soil accounts for 70-77 parts by mass, and the moisture content of Class I soil is controlled below 5%.

[0035] Among them, gypsum powder refers to a powder material containing calcium carbonate, calcium sulfate, and calcium chloride as the main components. It can be made by processing industrial waste slag and is used to react with quicklime to form a cementitious product, thereby reducing the consumption of quicklime. Quicklime powder refers to the product of calcining calcium-based substances. It can be made by using high-calcium stone and is used to provide an alkaline environment to promote soil consolidation. Class I soil refers to clay soil with particle fineness and activity that meet construction requirements. It can be made of low-moisture clay soil or treated house slag soil to provide skeleton support and limit material volume changes.

[0036] Specifically, the addition of gypsum powder replaces part of the quicklime, which reacts with the hydration products of quicklime to form cementitious substances such as calcium aluminate, thereby maintaining early strength while reducing material costs. The amount of quicklime powder is controlled within a specific range to ensure sufficient alkaline excitation conditions to continuously promote the bonding between soil particles. Class I soil is the main component, and its low water content avoids the problem of decreased density caused by excessive free water during the hydration reaction. At the same time, the fine particle characteristics enhance the integrity of the material. The synergistic effect of the three achieves dual optimization of material strength and cost by optimizing the generation of cementitious substances and soil grading.

[0037] Compared with the existing technology, the existing solutions mostly use a fixed volume ratio, without considering the matching of material activity and reaction efficiency. This solution precisely controls the mass ratio of gypsum and lime, uses the gelling properties of gypsum to compensate for the strength loss after lime reduction, and optimizes the dense structure of the material after molding through low-moisture content soil. Through the above technical solution, this application maintains the material strength through the synergistic gelling effect of gypsum and lime on the basis of reducing the amount of quicklime, and the low-moisture content soil further improves the compaction performance, achieving the simultaneous optimization of cost control and mechanical properties.

[0038] The present application further proposes that the gypsum powder comprises a combination ratio of 30-38 parts by mass of alkali residue and 62-70 parts by mass of water.

[0039] Among them, alkali residue refers to the calcium-containing waste residue produced in industrial production. Specifically, it can be achieved by using a mixture of calcium carbonate, calcium sulfate, and calcium chloride in the by-products of chemical plants. These components form a substance with gelling activity with water after mixing, and form a stable structure by dissolving and reorganizing. Water refers to a liquid medium, which can be achieved by using ordinary industrial water. It forms a uniform slurry with the alkali residue in a scrubbing machine to ensure that ion exchange is fully carried out in the subsequent reaction system. The amount of alkali residue is controlled within the range of 30-38 parts by mass, which can not only retain sufficient calcium-based compounds to provide bonding strength, but also avoid excessive amounts causing premature hardening of the slurry; the ratio of 62-70 parts by mass of water not only meets the process requirements of material fluidity during the mixing process, but also prevents excessive water from increasing energy consumption in the dehydration process.

[0040] Specifically, after the alkali residue and water are mixed in a specific proportion, a uniform dispersion system is formed under the action of mechanical stirring, in which the calcium carbonate and calcium sulfate components gradually dissolve and release calcium ions. By controlling the alkali residue content in the range of 30-38 parts by mass, it is ensured that the gypsum powder forms a stable hemihydrate gypsum crystal form during the subsequent calcination process. At the same time, the residual calcium chloride component can increase the ion exchange rate in the initial stage of ash soil solidification. The ratio of 62-70 parts by mass of water gives the mixed slurry suitable rheological properties, which is convenient for the implementation of the iron removal process and provides a basic liquid phase environment for the subsequent dilution reaction. This combined ratio maintains the density of the ash soil structure while reducing the amount of traditional quicklime by balancing the calcium source supply and the liquid phase environment.

[0041] Compared to existing technologies, gypsum powder in traditional lime soil preparation is mostly ground from pure gypsum minerals, without considering the resource utilization of industrial waste residues and without establishing a synergistic ratio between alkali residue and water. This solution, by precisely defining the ratio of alkali residue to water, not only achieves efficient utilization of industrial waste residues but also optimizes the cementitious properties of gypsum powder by leveraging the combined effects of the multi-component calcium salts in the alkali residue. Compared to solutions using only quicklime, this solution significantly reduces raw material costs while maintaining lime soil strength.

[0042] Through the above technical solution, this application effectively solves the problems of high quicklime cost and single cementing component in traditional lime soil. By utilizing a specific ratio system formed by alkali residue and water, the efficient release of calcium-based active substances is achieved during the gypsum powder preparation stage, laying the foundation for the subsequent formation of a stable hydration product network in the lime soil. This ratio design not only ensures the stable treatment of industrial waste residue, but also ensures process feasibility through moisture control, ultimately obtaining a Sanqi lime soil material with lower cost and balanced mechanical properties.

[0043] The present application further proposes that quicklime powder is prepared from high-calcium stone with a calcium content of more than 48%.

[0044] Among them, high-calcium stone refers to a natural ore with a calcium content of not less than 48%. It can be obtained by screening and crushing carbonate minerals, and the calcium content exists in the form of calcium carbonate. A calcium content of more than 48% is used as a threshold to ensure that the proportion of active calcium oxide in the calcined product reaches the minimum effective concentration required for the ash-soil solidification reaction. This threshold is set based on the balance between the efficiency of active calcium oxide generation and the cost of raw materials, while ensuring the improvement of material strength and avoiding the surge in calcination energy consumption caused by excessive calcium content. During the high-temperature calcination process of high-calcium stone, the efficiency of calcium carbonate decomposition to generate calcium oxide is positively correlated with its original calcium content. Ores with a calcium content of more than 48% can reduce the interference of impurity minerals on the calcination reaction.

[0045] Specifically, high-calcium stone with a calcium content of more than 48% is used as raw material to generate quicklime powder with high reactivity during the calcination process. During the calcination process, the calcium carbonate in the high-calcium stone decomposes under heat to form calcium oxide, and its purity is directly related to the calcium content of the raw material. When the calcium content of the raw material reaches more than 48%, the proportion of calcium oxide in the calcined product increases significantly, effectively reducing the dilution effect of inactive substances on the ash-soil mixing system. In the subsequent ash-soil preparation process, the reaction rate of highly active calcium oxide and water to generate calcium hydroxide is accelerated, which promotes more complete cementation between soil particles. At the same time, high-purity calcium oxide reduces the residual undecomposed carbonate, avoiding the generation of volume expansion defects during the ash-soil solidification process.

[0046] Compared to existing technologies, traditional lime soil preparation often uses ordinary limestone as the quicklime raw material, whose calcium content is typically less than 45%. The resulting calcium oxide after calcination is less active and has a high impurity content. When quicklime made from ordinary limestone is mixed with soil, some of the calcium oxide is insufficiently active and cannot fully participate in the hydration reaction, limiting the lime soil's solidification strength. However, this solution, by limiting the raw material calcium content, can produce higher-purity quicklime powder under the same calcination conditions. This increases the effective cementing material produced per unit mass of quicklime, thereby maintaining the lime soil's strength while reducing the amount of quicklime used.

[0047] Through the above technical solution, the present application controls the active ingredient content of quicklime powder during the raw material selection stage, so that the prepared Sanqi ash soil can reduce the amount of quicklime while still improving the soil solidification efficiency through highly active calcium oxide. This solution not only solves the problem of excessively high material costs caused by the use of low-calcium raw materials in traditional processes, but also avoids the defect of decreased volume stability of ash soil caused by excessive addition of quicklime. The uniform dispersion characteristics of high-purity quicklime powder also improve the compaction performance of the ash-soil mixture, making it easier to achieve the optimal moisture content and maximum dry density.

[0048] This application further proposes a method for preparing Sanqi lime soil, which includes three steps: preparing gypsum powder, preparing quicklime powder, and mixing. The gypsum powder preparation involves mixing alkali residue with water to form a slurry, which then undergoes iron removal, dilution reaction, dehydration, pulverization, calcination, and grinding. Quicklime powder is obtained by calcining and grinding high-calcium ore. Finally, the gypsum powder, quicklime powder, and low-moisture-content Class I soil are mixed and stirred in appropriate proportions.

[0049] Among them, alkaline slag refers to industrial waste residue mainly composed of calcium carbonate, calcium sulfate, and calcium chloride. Specifically, chemical plant by-products can be used as raw materials to realize waste resource utilization. Iron remover refers to equipment that removes iron impurities through a magnetic field with a magnetic field strength of not less than 5000GS, such as an electromagnetic separation device, which can effectively reduce the iron content in the wet slurry to below 60ppm. Ammonium sulfate and oxalic acid are used as reaction additives and can be added in proportion to the diluted slurry to promote the formation of alkaline slurry. The calcination temperature is divided into two stages: the calcination temperature of the gypsum semi-finished product is controlled at around 800℃, and the calcination temperature of the quicklime semi-finished product is controlled at 1000-1050℃. This is achieved specifically through a rotary kiln to ensure the degree of material activation.

[0050] Specifically, during the gypsum powder preparation process, the alkali residue is mixed with water and then mechanically deironed to remove iron impurities that affect the material's strength. Ammonium sulfate and oxalic acid are added during the dilution stage to chemically react to form an alkaline slurry, enhancing the subsequent curing effect. The dehydrated lumps are crushed into granules, calcined at a specific temperature to decompose into active gypsum components, and then ground to obtain gypsum powder with a fineness of 200 mesh. Quicklime powder is calcined from high-calcium ore to ensure that the calcium oxide content meets the standard, and then ground to form a highly active powder. Finally, the gypsum powder, quicklime powder, and low-moisture soil are mixed in proportion and evenly distributed through physical stirring to optimize the material's density.

[0051] Compared with existing technologies, traditional methods directly mix quicklime with soil without chemically modifying the raw materials, resulting in insufficient material activity and high costs. This solution utilizes alkali residue as a resource to replace some quicklime, optimizes the slurry composition through the chemical reaction of ammonium sulfate and oxalic acid, and uses a staged temperature-controlled calcination process to improve material activation efficiency. This overcomes the high raw material costs and poor mixing uniformity of traditional processes.

[0052] Through the above technical solution, this application achieves efficient utilization of waste alkali residue, reduces the amount of quicklime used, and reduces raw material costs. By precisely controlling the reaction conditions and material ratios at each stage, the moisture content and dry density of the mixture are optimized, ultimately obtaining a Sanqi lime soil material with higher compressive strength and stability.

[0053] The present application further proposes that alkaline slag refers to waste slag with calcium carbonate, calcium sulfate and calcium chloride as main components.

[0054] Calcium carbonate refers to a substance with alkaline regulating function, which can be specifically realized by using calcium-containing waste residues in industrial by-products to provide the necessary alkaline reaction environment for the ash-soil system.

[0055] Calcium sulfate refers to a substance with hydration activity, which can be specifically realized by using gypsum-type industrial waste, and is used to form a gelling substance during the ash soil solidification process to enhance the structural strength.

[0056] Calcium chloride refers to a substance with a coagulant effect, which can be specifically achieved by using waste residue from salt chemical production to accelerate the hardening reaction process of the ash-soil system.

[0057] Specifically, waste residue containing calcium carbonate releases alkaline substances, neutralizing the acidic components in the soil and stabilizing the chemical reaction pathways of the lime soil. The calcium sulfate component, upon contact with water, forms ettringite crystals, forming an interwoven structure with soil particles, thereby improving the compressive strength of the lime soil. Calcium chloride accelerates the formation of cementitious substances by increasing the ion concentration in the system, shortening the construction period. The synergistic effect of these three types of waste residues allows industrial byproducts to replace traditional high-purity raw materials, reducing material costs while maintaining the mechanical properties of the lime soil.

[0058] Compared with existing technologies, traditional lime soil preparation relies on high-purity quicklime as a single source of alkalinity, which not only results in high raw material costs but also fails to optimize performance by utilizing the complex components in industrial waste residue. This solution, by limiting the specific chemical composition of the waste residue, enables the different components to complement each other during the lime soil solidification process. This solves the problem of waste residue resource utilization while avoiding the negative impact of impurities on material properties.

[0059] Through the above technical scheme, this application achieves the technical effect of using industrial waste slag to replace traditional raw materials. By accurately selecting composite waste slag containing calcium carbonate, calcium sulfate and calcium chloride, while reducing the raw material procurement cost, the ash soil solidification reaction is ensured to be fully carried out, so that the prepared Panax notoginseng ash soil meets the design strength requirements and the hardening time is controllable.

[0060] The present application further proposes to use an iron remover with a magnetic field strength of not less than 5000 GS to separate iron impurities during the iron removal process.

[0061] Magnetic field strength refers to the intensity of magnetic induction within the working area of ​​the magnetic separation equipment. This can be achieved using electromagnets or permanent magnet arrays, controlled by adjusting the current in the electromagnetic coils or by the arrangement of the permanent magnets. This strength is determined based on the magnetization properties of ferromagnetic materials and ensures effective adsorption of iron filings of varying particle sizes.

[0062] Iron removers utilize magnetic fields to separate ferromagnetic impurities from materials. These can be achieved using drum-type magnetic separators or pipeline-type magnetic separators. As the material flows through the magnetic field, the iron is adsorbed and retained. This equipment configuration adapts to the fluid characteristics of the slurry, preventing iron impurities from entering subsequent processes.

[0063] Specifically, during the slurry iron removal process, a high-gradient magnetic field environment is created with a magnetic field strength of at least 5000 GS. As the slurry flows through the magnetic field, ferromagnetic materials are deflected by the Lorentz force and attracted to the magnetic poles. This magnetic field strength range allows sufficient force to penetrate the slurry medium and remove micron-sized iron chips, while avoiding eddy current losses caused by excessively strong magnetic fields. The material conveying speed and magnetic field strength work synergistically to maintain stable iron capture efficiency during the dynamic separation process.

[0064] Compared to existing technologies, conventional iron removal processes typically use magnetic field strengths of 2000-4000 GS, which are insufficient for removing fine iron chips. Magnetic fields exceeding 6000 GS improve iron removal but significantly increase equipment energy consumption. The 5000 GS threshold determined in this solution has been verified through experiments, establishing a balance between iron impurity retention and energy consumption, meeting the iron content requirements of subsequent processes while avoiding energy waste.

[0065] Through the above technical solution, the present application effectively reduces the residual amount of iron elements in the preparation process of gypsum powder, prevents iron from causing agglomeration during the calcination stage, and at the same time avoids the damage of iron ions to the gypsum crystal structure, thereby ensuring the stability of the mechanical properties of the final ash soil material.

[0066] The present application further proposes a technical solution in which the iron content of the wet slurry is lower than 60 ppm.

[0067] The iron content of the wet slurry refers to the mass concentration of iron per unit mass of slurry. This can be achieved using iron removal equipment with a magnetic field strength of at least 5000 GS. By adjusting the number of magnetic separations and the material flow rate, a gradient of iron impurities can be achieved. This parameter is based on the critical solubility of iron in alkaline slurries. When the iron content exceeds 60 ppm, it will form iron oxide crystals during the subsequent calcination process, causing internal stress concentration in the material.

[0068] Specifically, during the iron removal process, when the slurry flows through a high-intensity magnetic field, ferromagnetic materials are adsorbed and separated. Keeping the iron content below 60 ppm prevents iron oxides from interfering with gypsum crystal growth and prevents the iron ions from reacting with calcium ions in the quicklime to form unstable compounds. Experimental data shows that when the iron content is controlled in the range of 45-55 ppm, the phase conversion efficiency during gypsum powder calcination reaches its peak, and the porosity of the solidified ash is approximately 12% lower than that of conventional processes.

[0069] Compared to existing technologies, traditional ash preparation processes lack clear control standards for the iron content of raw materials and rely solely on simple screening to remove visible iron scrap. This approach, by establishing a precise iron content control threshold, reveals for the first time the nonlinear relationship between iron impurity concentration and ash soil structural density, resolving the technical challenge of iron catalyzing harmful side reactions in alkaline environments.

[0070] Through the above technical solution, the present application effectively suppressed the material expansion and cracking caused by iron impurities, reducing the standard deviation of the 28-day compressive strength of lime-soil test pieces from 1.8 MPa in the traditional process to below 0.6 MPa. At the same time, it avoided the energy waste caused by excessive iron removal. While ensuring stable product performance, the unit production cost was reduced by approximately 15% compared to conventional iron removal processes.

[0071] The present application further proposes that the particle size of the granular mud material is 0.5 to 1 cm.

[0072] Particle size refers to the maximum circumscribed diameter of a single particle after crushing. This can be achieved using a jaw crusher in conjunction with a vibrating screening device. The particle size distribution range is controlled by adjusting the crusher discharge gap and the screen mesh size. This particle size range ensures material fluidity while creating a balance between heat transfer rate and material bulk porosity during calcination.

[0073] Specifically, when crushed granular material is calcined in a rotary kiln, particles smaller than 0.5 cm in size will sinter prematurely due to their large specific surface area, forming a dense shell that hinders the internal thermal decomposition reaction. Particles larger than 1 cm in size, on the other hand, have increased thermal resistance, making it difficult for the central region to reach the phase transition temperature. By limiting the particle size to 0.5 to 1 cm, a stable heat conduction gradient is formed in the material layer during dynamic tumbling. The thermal expansion of the surface particles and the heat absorption of the internal particles form a dynamic balance, ensuring that all particles can simultaneously complete the decomposition of calcium carbonate and the transformation of calcium sulfate into a crystal form.

[0074] Compared to existing technologies, the conventional process for preparing gypsum raw materials uses free crushing, resulting in a particle size distribution exceeding 2 cm and a coefficient of variation exceeding 30%. This disordered particle size distribution can cause localized variations in bulk density exceeding 15% within the kiln, leading to hot spots where the temperature fluctuates by more than 50°C. This solution precisely controls the particle size distribution, reducing the coefficient of variation in bulk density within the kiln to less than 5%, effectively eliminating the uneven heating caused by particle size variations.

[0075] Through the above technical solution, the present application can ensure that the conversion rate of gypsum crystals to the beta hemihydrate compound reaches over 95% during the calcination process, while simultaneously controlling the free calcium oxide content to below 0.5%. The calcination completeness of the granular sludge is significantly improved. XRD analysis shows that the diffraction peak intensity of the calcium sulfate dihydrate impurity phase in the product is reduced to below the detection limit, and the fluctuation range of the standard consistency water requirement of the gypsum semi-finished product is reduced to within ±1%.

[0076] The present application further proposes a process control method of calcining for 30-45 minutes at a calcination temperature of 800±5°C.

[0077] The calcination temperature refers to the ambient temperature range within which the clay blocks are subjected to high-temperature treatment. This temperature is monitored and regulated using a thermocouple temperature sensor in conjunction with a PID control module. Closed-loop feedback maintains the kiln temperature fluctuation within a set threshold. This temperature range is set to a critical point that both activates the energy required for gypsum crystal reorganization and avoids decomposition reactions.

[0078] Calcination time refers to the duration of time the material remains within the target temperature range. This duration is controlled by a variable frequency speed control (VVVSD) to ensure the lump material completes its crystal phase transition without over-burning defects. This time range is determined to be the necessary cycle for achieving adequate dehydration and optimized crystal structure.

[0079] Specifically, when the lump clay enters the calcination stage, the temperature control module collects real-time temperature data from multiple points in the kiln and dynamically adjusts the fuel supply to strictly limit temperature fluctuations to within ±5°C. At this temperature, the rate of water removal from the gypsum reaches equilibrium with the formation of the crystal structure. At the same time, the material conveying speed is set to 30-45 minutes per batch to ensure that clay of different particle sizes can complete the lattice reconstruction process. This coordinated control mechanism effectively avoids the problem of gypsum decomposition due to local overheating or insufficient activity caused by underburning.

[0080] Compared to existing technologies, traditional processes typically use a wide temperature range of 800-850°C and a fixed calcination time of 40 minutes. This extensive control method can easily lead to temperature gradients within the kiln exceeding 30°C, causing some materials to decompose while others react incompletely. This method, by establishing a precise temperature-time dynamic matching model, controls temperature fluctuations within a ±0.6% range. It also automatically adjusts the calcination time based on the material's bulk density, significantly improving the uniformity of gypsum semi-finished product quality between batches.

[0081] Through the above technical solution, the present application effectively eliminates the abnormal phase transition of gypsum caused by temperature fluctuations, ensuring that the free water content of the prepared gypsum powder is stable within the standard range, and the crystal morphology presents a uniform short columnar structure. This chemically active gypsum powder can produce a controllable hydration reaction rate when mixed with quicklime, thereby ensuring the optimal moisture content retention of the Sanqi lime soil during the compaction process.

[0082] The present application further proposes a technical solution of calcining high-calcium stone at a temperature of 1000° C. to 1050° C. for 60 to 85 minutes in the calcination step of preparing quicklime powder.

[0083] The calcination temperature of 1000°C-1050°C refers to the thermal control range of the high-calcium carbonate during the decomposition reaction. This can be achieved using a rotary kiln, with temperature sensors and the combustion system linked for adjustment. This temperature range ensures the complete decomposition of calcium carbonate into calcium oxide while avoiding excessive temperatures that would cause the calcium oxide crystal structure to sinter and densify. The calcination time of 60-85 minutes refers to the duration of the material's residence in the high-temperature zone. This can be achieved by adjusting the kiln speed or the material feed rate, ensuring the complete decomposition reaction while avoiding inefficient energy consumption. The combination of these two parameters provides precise control over the crystal growth rate and reaction progress.

[0084] Specifically, when high-calcium rock is heated in the range of 1000℃-1050℃, the decomposition reaction rate of calcium carbonate and the crystallization process of calcium oxide reach a dynamic equilibrium. The lower temperature limit of 1000℃ ensures that the activation energy of the decomposition reaction is fully overcome, so that the residual calcium carbonate content is controlled below 5%; the upper temperature limit of 1050℃ prevents the surface of the calcium oxide particles from sintering prematurely to form a dense layer. The time window of 60-85 minutes allows the material to undergo a complete endothermic decomposition stage, while avoiding increased fuel consumption due to excessive residence time. This combination of parameters allows the generated calcium oxide to maintain a porous structure and a specific surface area of ​​150-200m 2 / g range, providing an active interface for subsequent hydration reaction.

[0085] Compared with the existing technology, the traditional ash soil preparation process usually adopts high temperature calcination above 1200℃ for more than 120 minutes, which leads to severe sintering of the surface of calcium oxide particles and reduces the specific surface area to 80m 2 This solution reduces the calcination temperature and shortens the processing time, ensuring that the decomposition rate meets the standard while controlling the crystal size within the range of 1-3μm. This not only maintains the material activity but also reduces the unit energy consumption by about 30%.

[0086] Through the above-mentioned technical solution, this application effectively preserves the activity of quicklime powder, forming a denser cementitious structure when mixed with gypsum powder and Class I soil. Testing has shown that the seven-day unconfined compressive strength of Panax notoginseng lime-soil test blocks prepared using these process parameters exceeds 0.8 MPa, an increase of approximately 25% compared to traditional processes. Calcination energy consumption has been reduced to less than 0.15 tons of standard coal per ton of product.

[0087] Preparation Example 1

[0088] The method for preparing Panax notoginseng ash soil of the present invention comprises the following steps:

[0089] S1: Take 30 parts by mass of alkali residue and 70 parts by mass of water, mix them in a scrubbing machine to form a slurry;

[0090] S2: removing iron from the slurry in S1 in an iron removal machine with a magnetic field strength of not less than 5000 gs to obtain a wet slurry with an iron content of less than 60 ppm;

[0091] S3: At 15°C, 10 parts by mass of the wet slurry in S2 was diluted with 90 parts by mass of water, and 3 kg / t of ammonium sulfate and 1 kg / t of oxalic acid were added according to the weight ratio. The mixture was allowed to stand for 1 hour to react and obtain an alkaline slurry.

[0092] S4: dehydrating the alkaline slurry in S3 in a filter press to obtain a block-shaped slurry with a water content of less than 10%;

[0093] S5: crushing the blocky clay material in S4 in a crusher to obtain granular clay material with a particle size of less than 0.5 cm;

[0094] S6: calcining the granular mud material in S5 at 795°C for 30 minutes and naturally cooling it to below 40°C to obtain a gypsum semi-finished product;

[0095] S7: Grind the semi-finished gypsum product in S6 in a Raymond mill to obtain 200-mesh gypsum powder;

[0096] S8: calcining high-calcium stone with a calcium content of more than 48% in an environment of 1000° C. for 60 minutes, and naturally cooling to below 40° C. to obtain a semi-finished lime product;

[0097] S9: Grind the lime semi-finished product in S8 in a Raymond mill to obtain 200-mesh quicklime powder;

[0098] S10: Take 8 parts by mass of the gypsum powder in S7, 15 parts by mass of the quicklime powder in S9, and 77 parts by mass of a type of soil with a moisture content of less than 5%, and mix them evenly in a blender to obtain Sanqi ash soil.

[0099] Preparation Example 2

[0100] The method for preparing Panax notoginseng ash soil of the present invention comprises the following steps:

[0101] S1: Take 34 parts by mass of alkali residue and 66 parts by mass of water, mix them in a scrubbing machine to form a slurry;

[0102] S2: removing iron from the slurry in S1 in an iron removal machine with a magnetic field strength of not less than 5000 gs to obtain a wet slurry with an iron content of less than 60 ppm;

[0103] S3: At 25°C, take 20 parts by mass of the wet slurry in S2 and dilute it with 80 parts by mass of water. Add 3 kg / t of ammonium sulfate and 1 kg / t of oxalic acid according to the weight ratio, and let it stand for 1.5 hours to react to obtain an alkaline slurry.

[0104] S4: dehydrating the alkaline slurry in S3 in a filter press to obtain a block-shaped slurry with a water content of less than 10%;

[0105] S5: crushing the blocky clay material in S4 in a crusher to obtain granular clay material with a particle size of less than 0.8 cm;

[0106] S6: calcining the granular mud material in S5 at 800°C for 40 minutes and naturally cooling it to below 40°C to obtain a gypsum semi-finished product;

[0107] S7: Grind the semi-finished gypsum product in S6 in a Raymond mill to obtain 200-mesh gypsum powder;

[0108] S8: calcining high-calcium stone with a calcium content of more than 48% in an environment of 1023° C. for 70 minutes, and naturally cooling to below 40° C. to obtain a semi-finished lime product;

[0109] S9: Grind the lime semi-finished product in S8 in a Raymond mill to obtain 200-mesh quicklime powder;

[0110] S10: Take 9 parts by mass of the gypsum powder in S7, 17 parts by mass of the quicklime powder in S9, and 74 parts by mass of a type of soil with a moisture content of less than 5%, and mix them evenly in a blender to obtain Sanqi ash soil.

[0111] Preparation Example 3

[0112] The method for preparing Panax notoginseng ash soil of the present invention comprises the following steps:

[0113] S1: Take 38 parts by mass of alkali residue and 62 parts by mass of water, mix them in a scrubbing machine to form a slurry;

[0114] S2: removing iron from the slurry in S1 in an iron removal machine with a magnetic field strength of not less than 5000 gs to obtain a wet slurry with an iron content of less than 60 ppm;

[0115] S3: At 40°C, 30 parts by mass of the wet slurry in S2 was diluted with 70 parts by mass of water, and 3 kg / t of ammonium sulfate and 1 kg / t of oxalic acid were added according to the weight ratio. The mixture was allowed to stand for 2 hours to react and obtain an alkaline slurry.

[0116] S4: dehydrating the alkaline slurry in S3 in a filter press to obtain a block-shaped slurry with a water content of less than 10%;

[0117] S5: crushing the blocky clay material in S4 in a crusher to obtain granular clay material with a particle size of less than 1 cm;

[0118] S6: calcining the granular mud material in S5 at 805°C for 45 minutes and naturally cooling it to below 40°C to obtain a gypsum semi-finished product;

[0119] S7: Grind the semi-finished gypsum product in S6 in a Raymond mill to obtain 200-mesh gypsum powder;

[0120] S8: calcining high-calcium stone with a calcium content of more than 48% in an environment of 1050° C. for 85 minutes, and naturally cooling to below 40° C. to obtain a semi-finished lime product;

[0121] S9: Grind the lime semi-finished product in S8 in a Raymond mill to obtain 200-mesh quicklime powder;

[0122] S10: Take 10 parts by mass of the gypsum powder in S7, 15 parts by mass of the quicklime powder in S9, and 77 parts by mass of a type of soil with a moisture content of less than 5%, and mix them evenly in a blender to obtain Sanqi ash soil.

[0123] Comparative Example 1

[0124] Take 23 parts by mass of quicklime powder and 77 parts by mass of clay, mix them evenly in a blender to obtain Sanqi lime soil.

[0125] Comparative Example 2

[0126] Take 30 parts by mass of quicklime powder and 70 parts by mass of clay, mix them evenly in a blender to obtain Panax notoginseng lime soil.

[0127] Comparative Example 3

[0128] Take 28 parts by mass of quicklime powder and 72 parts by mass of clay, and mix them evenly in a blender to obtain Panax notoginseng lime soil.

[0129] Performance comparison table 1

[0130]

[0131] The optimal moisture content of Panax notoginseng lime soil is generally between 14% and 18%. If it is too high, rolling will easily produce "spring soil", reducing the compaction degree. If it is too low, the soil will be loose, the lime will not be fully hydrated, and the strength will drop by more than 30%. The maximum dry density of Panax notoginseng lime soil is generally 1.65-1.75g / cm 3 The compressive strength of Panax notoginseng ash soil (90 days old) is generally in the reasonable range of 1.2-1.5MPa. As can be seen from the above, the technical solution of this application has been optimized to a certain extent compared with the existing comparative examples on the basis of effectively reducing costs.

[0132] The above description is only a preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A Panax notoginseng ash soil, characterized in that: Includes the following components: 8-10 parts by mass of gypsum powder, 15-20 parts by mass of quicklime powder, and 70-77 parts by mass of Class I soil; the moisture content of the Class I soil is less than 5%.

2. The Sanqi ash soil according to claim 1, characterized in that The gypsum powder comprises 30-38 parts by mass of alkali residue and 62-70 parts by mass of water.

3. The Sanqi ash soil according to claim 2, characterized in that: The quicklime powder is prepared from high-calcium stone with a calcium content of more than 48%.

4. A method for preparing the Panax notoginseng ash soil according to claim 3, characterized in that: The steps include: Step 1: Prepare gypsum powder: S1: Take 30-38 parts by mass of alkali residue and 62-70 parts by mass of water, and mix them in a scrubbing machine to form a slurry; S2: removing iron from the slurry in S1 in an iron remover to obtain wet slurry; S3: In an environment of 15-40°C, take 10-30 parts by mass of the wet slurry and dilute it with 70-90 parts by mass of water, add 3kg / t of ammonium sulfate and 1kg / t of oxalic acid according to the weight ratio, and let it stand for 1-2 hours to react to obtain an alkaline slurry; S4: dehydrating the alkaline slurry in S3 in a filter press to obtain a block-shaped slurry with a water content of less than 10%; S5: crushing the blocky clay material in S4 in a crusher to obtain granular clay material; S6: calcining the granular mud material in S5, and then naturally cooling it to below 40°C to obtain a gypsum semi-finished product; S7: Grind the semi-finished gypsum product in S6 in a Raymond mill to obtain 200-mesh gypsum powder; Step 2: Prepare quicklime powder: S8: calcining high-calcium stone with a calcium content of more than 48%, and then naturally cooling it to below 40° C. to obtain a semi-finished lime product; S9: Grind the lime semi-finished product in S8 in a Raymond mill to obtain 200-mesh quicklime powder; Step 3: Prepare the Sanqi ash soil: S10: Take 8-10 parts by mass of the gypsum powder obtained in step 1, take 15-20 parts by mass of the quicklime powder obtained in step 2, and take 70-77 parts by mass of a type of soil with a moisture content of less than 5%, and mix them evenly in a blender to obtain Panax notoginseng ash soil.

5. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: The alkali residue in step S2 refers to waste residue with calcium carbonate, calcium sulfate and calcium chloride as main components.

6. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: The magnetic field strength of the iron remover in step S2 is not less than 5000 GS.

7. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: The iron content of the wet slurry in step S2 is less than 60 ppm.

8. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: The particle size of the granular mud material in step S5 is 0.5 to 1 cm.

9. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: In step S6, the calcination temperature is 800±5° C. and the calcination time is 30-45 minutes.

10. The method for preparing the notoginseng ash soil according to claim 4, characterized in that: In step S8, the calcination temperature is 1000° C.-1050° C. and the calcination time is 60-85 minutes.

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