Process for producing potassium fulvate from a mineral source
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XINJIANG ORANGE BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-04-14
- Publication Date
- 2026-05-29
Smart Images
Figure CN122103222A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of humic acid preparation technology, and in particular to a production process for mineral-derived potassium fulvate. Background Technology
[0002] Potassium humate from mineral sources is a small-molecule potassium humate salt obtained by alkaline extraction and refining from weathered coal and lignite. It is rich in active functional groups such as carboxyl, phenolic hydroxyl, quinone, and methoxy groups, and has functions such as improving soil, increasing fertilizer utilization, promoting root development, enhancing crop stress resistance, and improving the quality of agricultural products. It is a core raw material for modern agricultural water and fertilizer integration, drip irrigation, and aerial spraying operations.
[0003] Currently, the industrial production of mineral-derived potassium humate generally employs the traditional high-temperature strong alkali stirring extraction process, which suffers from the following insurmountable technical defects:
[0004] Low extraction efficiency: Relying solely on mechanical stirring and alkaline hydrolysis, the internal structure of coal particles is not sufficiently destroyed, fulvic acid is not completely dissolved, and the extraction rate is only 50%-60%, resulting in serious waste of raw materials.
[0005] High energy consumption and long cycle: The reaction temperature is 80-100℃, the reaction time is 4-6 hours, the steam and electricity consumption is large, the equipment utilization rate is low, and the cost per ton is high.
[0006] Poor product quality: High temperature and strong alkali cause fulvic acid to oxidize and degrade, and cross-link macromolecules, resulting in a wide molecular weight distribution (500-5000Da). It has poor water solubility, is prone to flocculation, leaves residue, has weak resistance to hard water, and is not suitable for drip irrigation systems.
[0007] Environmental pressure is high: large alkali consumption, high subsequent acid neutralization load, and large amount of wastewater generated; traditional hot air / spray drying has high energy consumption, is prone to carbonization, and results in a large loss of product activity.
[0008] While there have been attempts at ultrasound-assisted extraction in existing technologies, these are mostly small-scale laboratory tests. They have not formed a complete integrated system for industrial closed-loop control, online monitoring, multi-stage fine separation, and low-energy solar drying. These systems suffer from problems such as significant scale-up effects, unstable parameters, incomplete solid-liquid separation, high drying costs, and inability to achieve continuous production, making it difficult to meet the stable industrial production needs of 200,000 tons per year. Summary of the Invention
[0009] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a production process for mineral-derived potassium fulvic acid. By deeply coupling ultrasonic-assisted weak-alkali low-temperature closed-loop extraction with a solar-powered intelligent drying system, this process achieves efficient extraction, fine separation, low-consumption drying, and high-quality output of fulvic acid, solving the bottleneck problems of low extraction rate, high energy consumption, poor quality, and high environmental pressure of traditional processes.
[0010] I. Technical Problem Solved by the Invention (1) Strengthen the crushing and deagglomeration of coal particles to increase the extraction rate of fulvic acid to 65%-75% and improve the utilization rate of raw materials; (2) Low-temperature (45-55℃) and short-time (30-60min) extraction is adopted, which saves more than 40% of energy and shortens the reaction time by 80%; (3) Reduce KOH usage by 20% to reduce neutralization load and wastewater generation, thus achieving cleaner production; (4) Control the molecular weight of the product to 300-3000 Da, increase the proportion of small molecules, and achieve full water solubility and no residue at 25℃; (5) Solar drying is adopted, which produces no wastewater, no carbonization, and low power consumption, significantly reducing drying costs; (5) Construct a fully automated control system to adapt to continuous and stable production of 200,000 tons per year.
[0011] II. Technical Solution Adopted by the Invention to Solve the Technical Problem A production process for mineral-derived potassium humate, with the following specific steps: (1) Preparation of raw coal slurry Raw material pretreatment: Weathered coal and / or lignite are fed into the hopper by a loader, and then fed into the crusher by a vibrating feeder and belt conveyor to be crushed to a particle size of <20mm, preferably <10mm; Metering and Pulping: After crushing, the material is conveyed quantitatively by a metering belt, mixed with the system circulating water in proportion, and sent to a ball mill for grinding until the coal slurry particle diameter is <200 mesh; Storage and transportation: Qualified coal slurry is sent into the coal slurry storage tank and then transported to the buffer tank of the extraction station by the slurry pump for later use.
[0012] (2) Ultrasonic-assisted weak alkali low-temperature closed-loop extraction This step is the core innovation of this invention, employing closed-loop control, online monitoring, and ultrasonic coordination. The specific process is as follows: 2.1 Ingredient Batching and Feeding A 30m³ closed reactor was used, and pretreated coal slurry was added to the reactor through a powder weighing scale at a solid-liquid ratio of 1:8-1:10. Start the metering pump, add 2%-3% KOH aqueous solution to the set level, turn on the anchor stirrer, and stir for 10 minutes to mix the materials evenly. The online pH meter monitors the pH in real time, and KOH solution is added to adjust the pH to 11-12. pH, temperature, and liquid level data are recorded.
[0013] 2.2 Heating and Temperature Control Hot water is introduced into the jacket of the reactor and the temperature is slowly raised to 45-55℃. The constant temperature mode is then activated. Temperature interlock control: When the temperature is >55℃, it automatically switches to cold water cooling to prevent humic acid oxidation and degradation; The entire process is sealed to prevent ammonia volatilization and material contamination.
[0014] 2.3 Ultrasonic-assisted extraction Start the ultrasonic generator, set the power to 3-5kW and the frequency to 25-30kHz, and continue extraction for 30-60 minutes. The central control system automatically samples and tests the transmittance of the filtrate every 15 minutes. The target transmittance is ≥90%. Once the target is met, the extraction is terminated early. If the transmittance is lower than 85%, the ultrasonic time is automatically extended by 10-15 minutes or KOH is added to adjust the pH to 12 until it meets the requirements.
[0015] In this step, the ultrasonic cavitation effect generates microjets, shock waves and microconvection, which destroy the dense structure of coal particles, accelerate KOH penetration, and promote the depolymerization of humic acid macromolecules into small molecule fulvic acid. In this step, the extraction rate of potassium humate reaches 65%-75%, which is 10-15% higher than the traditional method; the overall time is 30-60 minutes, which is more than 80% shorter than the traditional method; the whole process is carried out at low temperature without high pressure, saving about 40% of energy; the amount of KOH used is reduced by 20%; the molecular weight of potassium humate is 300-3000 Da, with a high proportion of small molecules and an 8%-12% increase in functional group activity.
[0016] (3) Settling and two-stage solid-liquid separation Stop ultrasonication and stirring, let the extract stand for 5 minutes to release bubbles and residual stress; the extract is then subjected to primary separation by a horizontal spiral centrifuge and fine separation by a disc centrifuge to obtain crude potassium humate solution; the moisture content of the coal slag after separation is ≤35%, and it is transported to the comprehensive utilization area; the light transmittance of the crude potassium humate solution is ≥90%, and it enters the dry chemical section.
[0017] (4) Drying treatment The drying process uses a solar drying system, which includes a solar drying greenhouse, a turner, a weather monitoring system, a circulating fan, a dehumidifying fan, an automatic feeding and discharging system, and an electrical control system.
[0018] 4.1 Setting up a solar-powered drying greenhouse Two three-row solar drying greenhouses are set up, each measuring 140m long and 38.4m wide, with a total area of 10,752㎡. The main structure is steel, with a high-transmittance heat-insulating covering layer. Air inlets and outlets are set on the gable walls at both ends to form a stable convection channel. The interior of the greenhouse is divided into a feeding area, a drying operation area, and a discharging area.
[0019] 4.2 Setting up the compost turner A 140m long track is laid along the longitudinal direction of the greenhouse, with a track level deviation of ≤±3mm; one drying-specific turning machine is configured every 12.8m span, for a total of 6 machines; the turning machine has a working width of 12.8m, a turning motor of 5.5kW, and a traction motor of 3kW; the turning depth is continuously adjustable from 0-300mm, the walking speed is frequency-adjustable from 0.5-1.5m / min, and the turning speed is 30-60r / min; it adopts a reciprocating tracking automatic operation mode, turning once every 30-60 minutes during the high moisture content stage (75%→40%), and once every 60-120 minutes during the low moisture content stage (40%→15%).
[0020] 4.3 Ventilation System Setup 96 circulating fans (0.55kW / unit) are evenly distributed inside the greenhouse to form a strong convective air field; 30 dehumidifying fans (0.37kW / unit) are installed high on the gable wall to exhaust humid air and maintain the indoor relative humidity ≤30%.
[0021] 4.4 Automatic Control System Settings Equipped with a meteorological monitoring system, it collects temperature, humidity, light, and wind speed in real time; the PLC control system links and adjusts the turning machine, circulating fan, and dehumidifying fan to stabilize the greenhouse temperature at 40-90℃ and relative humidity ≤30%; the material is evenly spread with a thickness of 80-150mm and dried to a moisture content of ≤15% at the output, with no wastewater, no carbonization, and no clumping throughout the entire process.
[0022] 4.5 Drying effect The daily processing capacity is 100 tons of raw material, with a daily water evaporation rate of 71 tons. The drying cost per ton is 17.87 yuan, and the drying efficiency is 2-5 times that of natural sun drying. The product retains its activity completely and is fully water-soluble with no residue at 25℃.
[0023] (5) Finished product packaging After drying, the finished product is conveyed to the packaging section by belt conveyor or screw conveyor, where it is automatically metered, sealed, and stacked to obtain highly active mineral-derived potassium humate.
[0024] The beneficial effects of this invention are: This invention utilizes ultrasonic cavitation to disrupt the structure of coal particles and enhances the penetration of alkaline solution and the depolymerization of humic acid, achieving a fulvic acid extraction rate of 65%–75%, which is 10–15 percentage points higher than that of traditional processes, and significantly improving the utilization rate of raw materials.
[0025] The ultrasonic-assisted extraction of this invention only takes 30 to 60 minutes, which is more than 80% shorter than the traditional 4 to 6 hours extraction time. The equipment utilization rate and production capacity are significantly improved, which can meet the needs of large-scale industrial continuous production.
[0026] The present invention controls the extraction temperature at a mild condition of 45-55℃, without the need for high temperature and high pressure, and reduces the overall energy consumption by about 40%; the amount of KOH used is reduced by 20%, reducing reagent costs and the load of subsequent neutralization treatment.
[0027] This invention reduces the degradation and cross-linking of fulvic acid under low-temperature conditions, controls the molecular weight of the product to 300-3000 Da, and has a higher proportion of small molecules; it is fully water-soluble at 25℃ with no residue, has a light transmittance of ≥90%, increases the active functional groups by 8%-12%, and has outstanding resistance to hard water and chelation ability, making it fully compatible with drip irrigation and fertigation systems.
[0028] This invention uses a solar-powered intelligent greenhouse for drying, relying on solar radiation and forced convection to evaporate moisture. The entire process generates no wastewater and produces no carbonized materials, reducing the drying cost per ton of material by more than 60%, resulting in significant energy-saving and environmental benefits.
[0029] This invention employs a two-stage separation process using horizontal centrifugation and disc centrifugation, resulting in a solid residue moisture content of ≤35% and a clear and transparent filtrate, thus reducing the load on subsequent treatments. The coal slag can be utilized as a resource without causing solid waste pollution.
[0030] This invention employs online monitoring and closed-loop automatic control throughout the entire process, with automatic linkage adjustment of temperature, pH, ultrasound, turning and sifting, and ventilation, ensuring stable and controllable production, high batch consistency of products, and low labor costs.
[0031] The production system of this invention produces no waste, recycles water, utilizes clean energy, and recycles solid waste, meeting the requirements of low-carbon environmental protection and high-quality development of modern agriculture, and possessing significant economic, social, and ecological benefits. Attached Figure Description
[0032] Figure 1 Schematic diagram of the production process of mineral-derived potassium humate; Figure 2 Diagram showing the structure and material flow of a solar-powered drying greenhouse. Detailed Implementation
[0033] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.
[0034] A production process for mineral-derived potassium humate is described below: (1) Preparation of raw coal slurry Weathered coal raw material is transported to the hopper by a loader, fed evenly by a vibrating feeder, and then sent to a large crusher by a belt conveyor to be crushed to a particle size of <10mm. After crushing, the material is accurately measured by a metering belt and mixed with the system circulating water at a mass ratio of 1:3. It is then sent to a ball mill for grinding until the coal slurry particle diameter is <200 mesh. The qualified coal slurry is sent to a coal slurry storage tank and then pumped to the buffer tank of the extraction station for later use.
[0035] (2) Ultrasonic-assisted weak alkali low-temperature closed-loop extraction Add the prepared coal slurry into a 30m³ reactor at a solid-liquid ratio of 1:9; Start the metering pump and add 2.5% KOH aqueous solution to the set level; Turn on the anchor mixer at 80 rpm and mix for 10 minutes to ensure the materials are evenly mixed. The pH of the system was adjusted to 11.5 by adding KOH solution after real-time monitoring with an online pH meter.
[0036] Turn on the jacketed hot water and slowly heat it to 50°C; then activate the constant temperature control. When the temperature exceeds 55℃, it automatically switches to cold water to cool down and prevent humic acid degradation.
[0037] Start the ultrasonic generator, set the power to 4kW and the frequency to 28kHz, and continue extraction for 45 minutes. The central control system automatically samples and tests the transmittance of the filtrate every 15 minutes. The transmittance is measured to be 92%, and the fulvic acid content meets the standard. Stop the ultrasonication and stirring.
[0038] (3) Settling and two-stage solid-liquid separation After extraction, the extract was allowed to stand for 5 minutes to release air bubbles and residual stress. The extract is transported through pipelines to an LW-450 horizontal screw centrifuge for primary separation at a speed of 3200 r / min to remove large particles of coal slag. After primary separation, the filtrate is fed into a disc centrifuge for fine separation at a speed of 7000 r / min to remove fine colloids and insoluble impurities, yielding a clear crude potassium humate solution. After separation, the coal slag is transported to the comprehensive utilization area.
[0039] (4) Solar-powered intelligent drying greenhouse drying The crude potassium humate solution (75% water content) is pumped into the feeding area of the solar drying greenhouse through a pipeline pump and then evenly spread by the material distribution system to a thickness of 120mm. The greenhouse consists of two interconnected, three-unit structures, each 140m long and 12.8m wide. 3 = 38.4m, with operating space reserved on both sides; Six compost turners are installed along the longitudinal track, each with an operating width of 12.8m, a traction motor of 3kW, and a compost turner motor of 5.5kW. The turning depth is set at 150mm, the walking speed at 1.0m / min, and the turning speed at 45r / min. The greenhouse is equipped with 96 circulating fans and 30 dehumidifying fans, which are controlled by a meteorological monitoring system to maintain an indoor temperature of 45-60℃ and a relative humidity of ≤30%. During the high moisture content stage (75%→40%), the soil was turned over once every 45 minutes; during the low moisture content stage (40%→15%), the soil was turned over once every 90 minutes. Once the material has dried to a moisture content of 15%, it is conveyed to the finished product warehouse via a belt conveyor.
[0040] (5) Finished product packaging After drying, the finished product is conveyed to the packaging section via a sealed belt, where it is metered, sealed, and stacked by an automatic packaging machine to obtain the finished product of mineral-derived potassium humate.
[0041] In this embodiment, Fulvic acid extraction rate: 72.3% Molecular weight distribution: 300-2800 Da Water solubility at 25℃: Completely water-soluble, leaves no residue. Potassium content: 12.3% Content of active functional groups: 10.5% higher than that of traditional processes. Filtrate transmittance: 92%.
[0042] Based on the disclosure in the foregoing specification, those skilled in the art can make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and alterations to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.
Claims
1. A production process for mineral-derived potassium humate, characterized in that: Includes the following steps: (1) Preparation of raw coal slurry: Weathered coal and / or lignite are crushed, metered, mixed with water, and ball-milled to a particle size of <200 mesh to obtain coal slurry; (2) Ultrasonic-assisted weak-base low-temperature closed-loop extraction: Add coal slurry and KOH aqueous solution to the reaction vessel at a solid-liquid ratio of 1:8-1:10, stir evenly, adjust the pH to 11-12, raise the temperature to 45-55℃, start ultrasonic-assisted extraction with a power of 3-5kW and a frequency of 25-30kHz, extract for 30-60min, monitor the transmittance online throughout the process, and obtain the extract. (3) Solid-liquid separation: The extract was allowed to stand for 5 minutes, and then subjected to initial separation in a horizontal screw centrifuge and fine separation in a disc centrifuge to obtain crude potassium humate solution with a coal slag moisture content ≤35%. (4) Drying treatment: The crude potassium humate solution was fed into a solar drying system for drying, yielding the finished product of mineral-derived potassium humate.
2. The production process of mineral-derived potassium humate according to claim 1, characterized in that: In step (2), the KOH aqueous solution has a mass concentration of 2%-3%, the stirring speed is 50-100 rpm, and the stirring time is 10 min.
3. The production process of mineral-derived potassium humate according to claim 1, characterized in that: In step (2), constant temperature interlock control is adopted. When the temperature is >55℃, cold water cooling is automatically switched to prevent humic acid degradation.
4. The production process of mineral-derived potassium humate according to claim 1, characterized in that: In step (2), online monitoring involves sampling every 15 minutes, with a transmittance target of ≥90%; when the transmittance is <85%, the ultrasound is automatically extended for 10-15 minutes or KOH is added to adjust the pH to 12.
5. The production process of mineral-derived potassium humate according to claim 1, characterized in that: In step (2), the extraction rate of potassium humate is 65%-75%, and the molecular weight of potassium humate is 300-3000 Da.
6. The production process of mineral-derived potassium humate according to claim 1, characterized in that: In step (4), the solar drying system includes a solar drying greenhouse, a turning machine, a meteorological monitoring system, a circulating fan, a dehumidifying fan, an automatic feeding and discharging system, and an electrical control system. The crude potassium fulvate solution is sent into a solar drying greenhouse, where it is heated by solar radiation, continuously turned by a turning machine, strongly convected by a circulating fan, dehumidified by a dehumidifying fan, and the temperature and humidity are regulated by an automatic weather system to obtain the finished mineral potassium fulvate product. The main body of the solar drying greenhouse is a steel structure, with a high light transmittance and heat insulation covering layer. Air inlets and outlets are provided on the gable walls at both ends to form a convection channel. The solar-powered drying greenhouse is internally divided into a feeding area, a drying operation area, a sludge drying area, and a discharging area. The light transmittance of the solar drying greenhouse is ≥80%.
7. The production process of mineral-derived potassium humate according to claim 6, characterized in that: The automatic feeding and discharging system includes a feeding system and a discharging system. The feeding system uses a pipeline pump for feeding, and the flow rate is automatically controlled.
8. The production process of mineral-derived potassium humate according to claim 7, characterized in that: The discharge system uses a belt conveyor or a screw conveyor, and its discharge end is sealed to the finished product silo.
9. The production process of mineral-derived potassium humate according to claim 6, characterized in that: The turning machine moves continuously along the long side track of the solar drying greenhouse.
10. The production process of mineral-derived potassium humate according to claim 6, characterized in that: The internal temperature of the solar drying greenhouse is controlled at 40-90℃, the humidity is ≤30%, and the output moisture content is ≤15%.