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CN-122012100-A - Preparation method of slow-release type industrial solid waste-based acid soil conditioner

CN122012100ACN 122012100 ACN122012100 ACN 122012100ACN-122012100-A

Abstract

The invention discloses a preparation method of a slow-release type industrial solid waste base acid soil conditioner, and belongs to the technical field of intersection of soil remediation and industrial solid waste resource utilization. The coal-fired power plant fly ash is used as a core substrate, and fully decomposed livestock manure organic fertilizer, quicklime, ground phosphate rock and calcium bentonite are used as auxiliary raw materials. The raw materials are pretreated, then the dry materials are sequentially mixed to ensure uniform components, the materials are conditioned by wet mixing to be in a state of 'being agglomerated by hand and being loose by hand', the wet materials are granulated, the particle size is controlled to be 2-3mm, the temperature is controlled to be 60-80 ℃ by hot air drying, and finally the materials are cooled and packaged after the water content is not more than 10%. The modifier can stabilize the pH value of acid soil to be more than 6.0-6.5 for more than 6 months, reduce the volume weight of the soil by 15-20%, lead the slow release period of nitrogen, phosphorus and potassium nutrients to be more than 100 days, reduce the improvement cost per mu to below 300 yuan, and consume 0.60-0.75 ton of industrial solid waste per ton of modifier, thereby realizing the cooperation of industrial solid waste recycling and soil restoration, and particularly adapting the characteristics of karst acid soil, southern red soil leaching and poor fertilizer retention.

Inventors

  • LIU ZHU
  • CHEN KANG
  • LI BAIZHANG
  • CUI MIN
  • HAO XIXI
  • WEN SHUPENG
  • Long en
  • YANG YANG
  • LI YI
  • ZHOU XIAOZHI
  • FENG YUN
  • LIU YU

Assignees

  • 贵州省黔地精开科技有限公司

Dates

Publication Date
20260512
Application Date
20260127

Claims (10)

  1. 1. The preparation method of the slow-release type industrial solid waste-based acid soil conditioner is characterized by comprising the following steps of: (a) The optimization and the proportion of the raw materials of the slow-release type industrial solid waste-based acid soil conditioner are determined (S1) Sampling and detecting target acid soil, obtaining pH value and phosphorus content data of the target acid soil, selecting an industrial solid waste substrate and additive proportion according to a detection result, and determining whether to add phosphate rock powder or not, wherein the industrial solid waste substrate is coal ash of a coal-fired power plant, the additives comprise livestock manure organic fertilizer and auxiliary conditioner, and the auxiliary conditioner comprises quicklime and calcium bentonite; (b) Pretreatment and weighing of the raw materials of the slow-release type industrial solid waste-based acid soil conditioner (S2) The pretreatment method of the additive comprises 1) crushing fully decomposed livestock manure organic fertilizer by a hammer crusher, feeding the crushed livestock manure organic fertilizer into a screening device to remove non-decomposed caking with overlarge grain size, 2) drying and crushing quicklime, screening the crushed quicklime to the specified grain size by the screening device, 3) crushing and screening calcium bentonite, weighing all pretreated raw materials in batches according to the proportion of each additive, weighing the total amount of each batch to be less than or equal to 200kg, ensuring that the proportion error is less than or equal to 1%, and if the phosphorus content in the detected target acid soil is less than 0.1%, adding phosphate rock powder, and grinding and screening the phosphate rock powder by the ball mill; (c) Slowly-releasing type industrial solid waste base acid soil conditioner weighing raw materials dry mixing (S3) Putting each batch of weighed industrial solid waste base materials, fully decomposed livestock and poultry manure organic fertilizer, quicklime, phosphate rock powder to be added and calcium bentonite into a double-shaft screw mixer together, setting the rotation speed of the mixer, the rotation speed difference parameters of the mixer, the mixer She Jianju and the mixing shaft, starting the mixer to mix dry materials until the dry materials are uniformly mixed, observing the material state in real time in the mixing process of the dry materials, if local caking occurs, timely processing, sampling and detecting after the mixing is finished, and ensuring that the component deviation of any sample is less than or equal to 2%; (d) Dry-mixed conditioning of slow-release type industrial solid waste-based acid soil conditioner dry mix (S4) Slowly adding water into the uniformly mixed dry materials, synchronously adjusting the rotating speed of a stirrer, adding water while stirring, adopting an infrared moisture meter to monitor the water content of the materials in real time, sampling and detecting for 1 time every 2min, controlling the water content of the materials to 18% -22%, and continuously wet-mixing until the materials reach a wet material in a state of 'holding the materials to form clusters, loosening the hands, and dispersing', namely, naturally crushing the clusters into particles with the particle size less than or equal to 5mm after falling to the ground; (e) Sustained-release industrial solid waste acid soil conditioner wet material granulation molding (S5) Wet materials which are wet mixed until the materials reach a state of' manual agglomeration and loosening, are sent into a granulator, parameters including the inclination angle, the rotating speed and the material filling rate of the granulator are regulated, and a small amount of water is supplemented into the granulator through an atomization spray nozzle to prepare the wet materials into wet particles, wherein the water supplementing amount is less than or equal to 3% of the total mass of the materials, the particle size of the particles is controlled to be 2-3mm, and the particle size distribution is periodically sampled and detected in the granulation process, so that the particle size qualification rate is more than or equal to 90%; (f) Sustained-release industrial solid waste acid soil conditioner wet granule drying and screening (S6) Sending the wet particles prepared in the step (e) into a hot air dryer, setting the temperature and wind speed parameters of the hot air, starting the dryer to dry the wet particles until the moisture content of the particles is less than or equal to 10%, and drying for 2-3 hours, sending the particles into a classifying screen after drying, wherein the classifying screen is provided with two layers of sieve holes of 2mm and 3mm, retaining qualified particles with the particle size of 2-3mm on the screen, and returning fine powder with the particle size of less than 2mm under the screen to the step (e) through a return pipeline for re-granulation; (g) Dry granule cooling package of slow release type industrial solid waste base acid soil modifier (S7) Sending qualified particles obtained by screening in the step (f) into a cooler, setting cold air temperature and wind speed parameters, cooling the particles to room temperature with the temperature of 25+/-5 ℃, carrying out quality detection on the cooled particles, wherein detection indexes comprise caking rate and water content, the caking rate is less than or equal to 5% and the water content is less than or equal to 10%, completing the slow-release type industrial solid waste-based acid soil modifier dry particles, sealing and packaging the qualified modifier particles by adopting moisture-proof packaging bags, arranging a drying agent in each bag, and storing the particles in a specified warehouse after packaging.
  2. 2. The preparation method of the slow-release type industrial solid waste-based acid soil conditioner according to claim 1 is characterized in that in the step (a), the additives and the proportions are determined according to the mass percentage, namely, 65-75 parts of coal ash of a coal-fired power plant, 15-25 parts of fully decomposed livestock manure organic fertilizer, 2-4 parts of quicklime, 0-3 parts of ground phosphate rock and 2-5 parts of calcium bentonite, the additive raw materials are preferably selected and the proportions are determined according to the pH value of target acid soil, the addition amount of quicklime is further refined according to the pH value of the target acid soil, the upper limit of the addition amount of quicklime is 4 parts when the pH value of the target acid soil is less than or equal to 4.5, the addition amount of quicklime is 3 parts when the pH value of the target acid soil is more than or equal to 4.5 and less than 5.0, the addition amount of quicklime is 2 parts when the pH value of the target acid soil is more than or equal to 5.0, the addition amount of quicklime is 3 parts when the phosphorus deficiency degree of the target acid soil is less than or equal to 0.05%, the phosphorus deficiency degree of the phosphorus content of the target acid soil is less than or equal to 0.05%, the phosphorus content of the ground phosphate rock is less than or equal to 1.08%, and the phosphorus content of the target acid soil is less than or equal to 1.08% is more than or equal to 1.0.
  3. 3. The preparation method of the slow-release type industrial solid waste base acid soil conditioner according to claim 1, wherein in the step (b), the specific parameters of the pretreatment of the industrial solid waste base material are that the drying temperature of the coal ash of the coal-fired power plant is 105-110 ℃, the drying time is 2-3h, and the water content after drying is ensured to be less than or equal to 5%; grinding time of a ball mill is 30-40min, sieving the ground livestock manure by a sieve of 80-100 meshes, controlling the sieving residue to be less than or equal to 5%, fully decomposed livestock manure organic fertilizer needs to meet specific requirements, namely, the content of SiO 2 is more than or equal to 70%, the death rate of ascarid eggs is more than or equal to 95%, the aperture of a sieve of a hammer crusher is 5mm, the crushed livestock manure passes through a sieve of 20-40 meshes, the quicklime drying temperature is 80-90 ℃, the drying time is 1-2h, the crushed livestock manure passes through a sieve of 40-60 meshes, the phosphorus ore powder needs to meet the content of P 2 O 5 , the grinding time of the ball mill is 40-50min, the ground livestock manure passes through a sieve of 100-120 meshes, the calcium bentonite needs to meet the content of montmorillonite to be more than or equal to 70%, the crushed livestock manure passes through a sieve of 60-80 meshes, the chemical component of the fly ash of a coal-fired power plant needs to meet specific requirements, specifically, the content of SiO 2 is more than or equal to 60%, the Al 2 O 3 is more than or equal to 20% -30%, the content of CaO is 5% -10%, the content of Fe 2 O 3 is 3% -8%, the porosity of the fly ash is more than or equal to 40%, the fully decomposed livestock manure is completely decomposed by cow manure, the cow manure or the fully decomposed by the method, the slaked coal is fully decomposed for 6 months, the block-shaped fly ash is not to be prepared, the slaked, the fly ash is not by the dry, the dry is free of the dry and the dry fly ash is free of the dry and has no-decomposed by the dry and has no hand, and has obvious hand feeling, and no bad taste content is ensured, avoiding the selection of powdered quicklime to prevent moisture absorption and caking.
  4. 4. The preparation method of the slow-release type industrial solid waste-based acid soil conditioner is characterized in that in the step (c), the mixing time of a double-shaft spiral stirrer is 5-8min, stirring blades of the stirrer are made of 304 stainless steel wear-resistant materials, the surfaces of the stirring blades are polished, the surface roughness Ra is less than or equal to 0.8 mu m, the adhesion of materials is avoided, stirring She Jianju is set to be 50-80mm, the rotating speed of a stirring shaft is set to be 30-40r/min, the rotating speed difference of the stirring shaft is 5-10r/min, shearing force is generated through the rotating speed difference, the mixing uniformity is improved, if lump agglomeration with the particle size of more than or equal to 10mm occurs in the dry material mixing process, the machine is stopped immediately, and the stirrer is restarted to continue mixing after the agglomeration is crushed to the particle size of less than or equal to 5mm in a manual crushing mode.
  5. 5. The preparation method of the slow-release type industrial solid waste-based acid soil conditioner according to claim 1 is characterized in that in the step (d), water which is slowly added into a uniformly mixed dry material is required to meet the requirement that the conductivity is less than or equal to10 mu s/cm, impurities generated by reaction of Cl - 、SO 4 2- plasma in the water and quicklime are avoided, the performance of the conditioner is influenced, the rotating speed of a stirrer is regulated to 50-60r/min and is higher than the rotating speed of a dry material mixing stage, the uniform distribution of water in the material is ensured, the total wet mixing time is 10-15min, after the wet mixing is finished, the water content of the material exceeds the range of 18-22%, the industrial solid waste substrate and the calcium bentonite mixed according to the original ratio are regulated, the water content is calculated according to the water content exceeding range, the water content is regulated, the water content of 2-3% of the total mass of the material is increased when the water content is lower than 18%, the water content is regulated, the water content of 1-1.5% of the total mass of the material is increased, and the condition that the wet mixing process is required to be observed in a final state, and no wet phenomenon is ensured.
  6. 6. The method for preparing the slow-release type industrial solid waste-based acid soil conditioner according to claim 1, wherein in the step (e), the granulator is selected according to the characteristics of productivity and materials, namely a disc granulator for 2% -3% of calcium bentonite, the daily productivity of which is less than or equal to 50 tons and the viscosity of materials are moderate, a drum granulator for 50-500 tons and the industrial solid waste substrate of which accounts for 60% -75%, a twin-roll extrusion granulator for 30-200 tons and the viscosity of materials, a fluidized bed granulator for 20-100 tons and the preparation of high-precision particles, and the water supplementing quantity is controlled to be less than or equal to 3% of the total mass of the materials; the diameter of the disc granulator is 1.2-1.5m, the dip angle is 30-45 degrees, the rotating speed is 20-30r/min, the particle size is measured for 10min, the disc granulator is coated with talcum powder, the diameter of the drum granulator is 1.5-3m, the dip angle is 2-5 degrees, the rotating speed is 8-15r/min, the particle size is measured for 15min, the roll diameter of the pair-roll extrusion granulator is 300-800mm, the extrusion force is 8-12MPa, the particle size is measured for 20min, the viscous material is purged by high-pressure air, the diameter of the fluidized bed granulator is 1-3m, the hot air is 65-75 ℃ and the particle size is measured for 12min, the spray amount or the air plate angle is adjusted, the spray nozzles used for granulation are all made of 316L stainless steel, the spray nozzle atomization particle size deviation is less than or equal to 10 mu m, the uniformity of water supplement is ensured, the particle size detection is 60 mesh and 80 target standard sieve is unified for 5min, the particle size is removed by a large block which is more than or equal to 5mm, the scraper blade is cleaned by a physical drum dryer after adhesion and the agglomeration is performed firstly, cleaning ineffective and spraying talcum powder, performing fluidized dead zone treatment by a fluidized bed granulator, and then, performing water content supplement measurement on the material, wherein the granulated material is immediately conveyed to a drying process by a belt conveyor, and a polytetrafluoroethylene liner is paved on the surface of the conveyor to prevent the material from remaining.
  7. 7. The preparation method of the slow-release type industrial solid waste acid soil conditioner is characterized in that in the step (f), a rapid dehydration mode, a stable dehydration mode and an overheat prevention sectional temperature control mode are sequentially adopted by a hot air dryer, the temperature of the rapid dehydration stage is 75-80 ℃ and the time is controlled to be 20-30 minutes, the temperature of the stable dehydration stage is 65-70 ℃ and the time is controlled to be 60-90 minutes, the temperature of the overheat prevention stage is 60-65 ℃ and the time is controlled to be 30-50 minutes, the temperature fluctuation of each stage is controlled to be within +/-2 ℃, specific time is adjusted in real time according to the water content monitored in real time, organic matter decomposition loss in an organic fertilizer caused by high temperature is avoided, the wind speed of the hot air dryer is set to be 1.5-2m/s, the hot air drying efficiency and the particle integrity are controlled through wind speed adjustment, a stainless steel woven mesh is adopted by a mesh screen of the classification screen, the temperature of the classification screen corresponds to 80 meshes, the temperature of the 3mm screen corresponds to 60 meshes, the tension is uniform, the tension deviation is less than or equal to 5%, the diameter of a backflow pipeline is 100-150mm, the backflow pipeline is controlled to be within the range of 60-150 ℃, the water content is not detected by a spiral moisture content detector is not equal to 10% and the water content is not detected in a water content detector, and the water content is not detected in a water content detector is not equal to 10% or equal to or less than 30 minutes.
  8. 8. The method for preparing the slow-release type industrial solid waste acid soil conditioner according to claim 1, wherein in the step (f), the sieve screen abrasion condition is required to be checked every 100 hours, a caliper is adopted to measure the sieve screen aperture, if the sieve screen aperture is enlarged by more than 0.1mm, the sieve screen is required to be replaced immediately, the sieving precision is ensured, the fine powder is required to be controlled to be matched with the feeding speed of a disc granulator in the reflux process, the reflux speed is 5-10kg/min so as to avoid overlarge load of the granulator caused by fine powder accumulation, the tail gas of the hot air dryer is discharged after being treated by a cloth bag dust removing device, the dust removing efficiency of the dust removing device is more than or equal to 99%, and the discharged dust concentration is less than or equal to 10mg/m 3 .
  9. 9. The preparation method of the slow-release type industrial solid waste acid soil conditioner is characterized in that in the step (g), filtered clean air is adopted as cold air of a cooler, the filtering precision is 10 mu m, dust pollution particles in the air are avoided, the cold air temperature of the cooler is 25+/-5 ℃, the air speed is 2-2.5m/s, the cooling time is 1-2h, the cooling temperature is less than or equal to 30 ℃, the cooling is carried out, the caking rate of the particles is detected by adopting a manual screening method, 1000g of cooled particles are weighed, the particles are screened by a 5mm standard sieve, the caking mass on the sieve is counted, the caking rate is ensured to be less than or equal to 5%, qualified particles are hermetically packaged by adopting polyethylene moisture-proof packaging bags with the thickness of 0.15-0.2mm, the packaging specification is 25kg or 50kg of polyethylene moisture-proof packaging bags, 50g of montmorillonite drying agents are arranged in each bag, the drying agents are required to be fixed at the corners inside the packaging bags, the moisture-proof conditioner particles are prevented from being directly mixed, and the product names, the raw materials, the production dates, the quality guarantee periods, recommended application methods, manufacturers, the contact telephones and notices are marked on the moisture-proof modifier.
  10. 10. The preparation method of the slow-release type industrial solid waste-based acid soil conditioner is characterized in that in the step (g), the designated warehouse is required to meet the dry ventilation condition, the relative humidity in the warehouse is less than or equal to 60%, the temperature is less than or equal to 35 ℃, direct sunlight is avoided, modifier bagged particles stored in the warehouse are stacked by adopting trays, the stacking height is not more than 10 layers, the tray spacing is not less than or equal to 50cm, the distance between the modifier bagged particles and the walls of the warehouse is not less than 30cm, air circulation is facilitated, the warehouse temperature and humidity and the modifier state are detected for 1 month during storage, if the moisture absorption and caking phenomenon of the modifier particles is found, timely tedding or re-drying treatment is required, performance sampling inspection is required before the modifier particles are applied, the detection indexes comprise pH adjustment capability and nutrient slow-release period, the soil pH can be stabilized to be more than 6.0-6.5 about 6 months after the target acid soil is applied, the slow-release period of nitrogen, phosphorus and potassium nutrients exceeds 100 days, and the volume weight of the acid soil is reduced by 15% -20%.

Description

Preparation method of slow-release type industrial solid waste-based acid soil conditioner Technical Field The invention relates to the technical field of acid soil restoration and industrial solid waste resource utilization intersection, in particular to a preparation method of a slow-release industrial solid waste-based acid soil conditioner, which is particularly suitable for taking coal ash of a coal-fired power plant as a core industrial solid waste substrate, and compounding completely decomposed livestock and poultry manure organic fertilizer, quicklime, ground phosphate rock and calcium bentonite. Background In agricultural production and ecological protection systems, acid soil restoration is a key link for guaranteeing cultivated land quality and improving crop yield. The pH value of the acid soil is generally in the range of 4.0-5.5 under the influence of long-term rain leaching effect, and the acid soil has multiple prominent problems, and the acid soil has the advantages of serious damage to the aggregate structure of the acid soil, obvious hardening phenomenon, volume weight as high as 1.4-1.6g/cm <3>, poor ventilation and water permeability, high leaching rate of basic nutrients such as nitrogen, phosphorus, potassium and the like, annual loss rate exceeding 40%, difficulty in meeting the whole growth period requirement of crops, high activity of heavy metals such as lead, cadmium and the like in the acid soil, easiness in absorption and accumulation of crops and threat to the safety of agricultural products, and the problems directly lead to 20% -30% yield reduction of economic crops such as corn, flue-cured tobacco, tea and the like. The current technology for improving acid soil mainly depends on three types of materials, but all the technologies have technical bottlenecks which are difficult to break through, and the comprehensive requirements of long-acting, low cost and resource utilization cannot be met. The single organic fertilizer improvement technology takes decomposed livestock manure and straw compost as core raw materials, can supplement organic matters of acid soil, improves water and fertilizer retention capacity, but has weak acid-base regulation capacity, 100kg of organic fertilizer applied per mu can only improve the pH value of the acid soil by 0.2-0.3 units, and organic acid which is easy to be generated by organic fertilizer decomposition is accumulated for a long time to aggravate soil acidification, meanwhile, the organic fertilizer raw materials have high cost, the improvement cost per mu reaches more than 800 yuan, and farmers in far-underdeveloped areas can bear the economic capacity, so that the large-scale popularization is difficult. The chemical modifier technology takes quicklime and calcium carbonate as main components, can rapidly neutralize the acidity of soil, 50kg of quicklime can be applied per mu to raise the pH value by 1-1.5 units within 1-2 weeks, but the action period is extremely short and is only 1-3 months, the pH value of the acidic soil is easy to rebound to the level before improvement, and more seriously, the chemical modifier can further damage the aggregate structure of the acidic soil, so that hardening is aggravated, the volume weight is raised by 0.1-0.2g/cm < 3 >, nutrients required by crops cannot be supplemented, and the agricultural production cost and the environmental burden are further increased by additionally applying chemical fertilizers. The existing composite modifier technology mostly uses chemical fertilizers such as diammonium phosphate, potassium chloride and the like as cores, and a small amount of lime powder is compounded, so that nutrient supplement and acid-base regulation can be considered, but industrial solid waste recycling is ignored. At present, industrial solid waste such as coal ash and coal gangue of coal-fired power plants is generated by more than 10 hundred million tons each year, the piling occupies more than 100 mu of land, the risk of heavy metal leakage to pollute underground water exists, meanwhile, the existing composite modifier lacks a nutrient slow release design, the loss rate of nitrogen, phosphorus and potassium is still more than 35 percent after being applied to acid soil, the improvement effect is poor in sustainability, the soil needs to be applied every 3-4 months, and the labor intensity of farmers is increased. In addition, the acid soil in the karst region has the characteristics of thin soil layer and poor water retention capacity, the existing modifier is difficult to adapt to the characteristics of the acid soil in the region, the single organic fertilizer is insufficient in water retention capacity and easy to be leached and lost along with rainwater, the chemical modifier is poor in cohesiveness with the acid soil and cannot form a stable acid-base buffer system, and the water retention structure is not designed aiming at the thin soil layer, so that the improvement effect is furth