A synergistic activation method and device for low-temperature potassium release of potassium feldspar

Abstract

The present application relates to the technical field of potassium feldspar potassium extraction, in particular to a synergistic activation method and device for low-temperature potassium release of potassium feldspar, which first constructs initial lattice defects on the surface layer of potassium feldspar through short-time mechanical activation, then implements flash heat shock and quenching on the thin layer material by using concentrated solar energy, and extends the crack network by means of thermal expansion difference; subsequently, the activated material is made to form a heterogeneous solid-solid contact interface with calcium-based particles, the interface charge transfer is used to reduce the calcium ion diffusion activation energy, and finally the calcium-induced lattice reconstruction and potassium release are completed under the conditions of medium-low temperature hydrothermal at 180-260 DEG C; the device comprises a raw material crushing unit, a mechanical activation unit, a solar light concentration flash heat shock unit, a calcium-based heterogeneous contact mixing unit, a low-temperature hydrothermal reaction kettle and a solid-liquid separation and recovery unit connected in sequence; the present application significantly reduces the reaction temperature and total energy consumption, improves the solar energy utilization efficiency and potassium activation effect, and is suitable for the dispersed in-situ processing scene of mineral resource enrichment areas.

Description

Technical Field

[0001] This invention relates to the field of potassium extraction technology from potassium feldspar, specifically a synergistic activation method and apparatus for low-temperature potassium release from potassium feldspar. Background Technology

[0002] Potassium is an irreplaceable macronutrient element in agricultural production. Potassium feldspar, as a potassium-containing silicate mineral with abundant reserves and wide distribution, is an important potential resource of insoluble potassium. However, the release of potassium from it has long been limited by factors such as the stable structure of the aluminosilicate framework and the difficulty in breaking Al-O and Si-O bonds, resulting in a relatively high overall extraction cost.

[0003] Currently, the main technical routes for potassium extraction from potassium feldspar and preparation of potassium fertilizer include high-temperature sintering, sub-molten salt method, mechanical activation method, and biological method. Among them, the high-temperature sintering method usually involves mixing potassium feldspar with calcium-based additives in a certain proportion, and then activating it at a high temperature of 1100-1250℃ by replacing potassium ions in the potassium feldspar lattice with calcium ions. This method has a high degree of technical maturity and a good potassium conversion rate, but the reaction temperature is high, energy consumption is large, and the requirements for the materials and structure of high-temperature equipment such as kilns are stringent. The sub-molten salt method uses a high-concentration NaOH solution as the reaction medium to decompose potassium feldspar under medium-high temperature and closed pressure conditions, and the potassium dissolution rate can reach more than 90%. However, this process consumes a large amount of strong alkali, has a complex alkali recovery system, and requires equipment with high corrosion resistance. The alkali recovery rate is the core factor determining the economic viability of the process. Mechanical activation uses high-energy ball milling to break up potassium feldspar particles and generate lattice defects such as dislocations, microcracks, and amorphous layers on the surface, thereby improving the solubility of potassium ions on the particle surface and near the surface. This method can be carried out at room temperature and does not require a large amount of chemical reagents, but its activation effect decreases marginally with increasing grinding time. Long-term grinding can easily cause particle agglomeration and offset some of the activation effect. The balance between activation energy consumption and treatment effect has always been a key issue restricting its large-scale promotion. In addition, some studies have proposed using calcium-based additives to hydrothermally modify potassium feldspar powder to obtain potassium fertilizer intermediate products with significantly improved potassium availability, providing a theoretical and technological basis for calcium-induced feldspar structural modification. However, related processes still generally rely on high processing temperatures to complete the lattice reconstruction process.

[0004] In terms of solar energy utilization, among the existing technical solutions involving high-temperature processing of silicate minerals, concentrated solar energy is mostly used as a heat source to replace traditional fuels or electric heating to maintain the material in a high-temperature sintering state. Essentially, it is still a steady-state heating mode, which fails to fully utilize the high energy flux density and instantaneous characteristics of concentrated solar energy, resulting in large capacity requirements and high initial costs for concentrated solar thermal systems.

[0005] Furthermore, the contact electrochemical effect has been applied in fields such as hydrometallurgical short-circuit galvanizing and gas-solid interface molecular activation, proving that interfacial charge transfer can effectively reduce reaction activation energy. However, there is currently no technical solution to introduce this principle into the solid-solid contact system between calcium-based particles and activated feldspar particles to accelerate the calcium-induced feldspar lattice reconstruction process. At the same time, existing technologies mostly implement mechanical activation, thermal activation, and chemical activation independently, failing to form a multi-field coupling mechanism that integrates lattice defect control, heterogeneous interfacial contact electrochemistry, and calcium-induced hydrothermal reconstruction. This makes it difficult to achieve efficient potassium release from potassium feldspar at medium and low temperatures below 260℃. Therefore, in light of the above situation, there is an urgent need to develop a synergistic activation method and device for low-temperature potassium release from potassium feldspar to overcome the shortcomings in current practical applications. Summary of the Invention

[0006] The purpose of this invention is to provide a synergistic activation method and apparatus for low-temperature potassium release from potassium feldspar, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A synergistic activation device for low-temperature potassium release from potassium feldspar includes a raw material crushing unit and a solid-liquid separation and recovery unit, as well as a mechanical activation unit, a solar concentrating flash thermal shock unit, a calcium-based heterogeneous contact mixing unit, and a low-temperature hydrothermal reactor.

[0009] The discharge end of the raw material crushing unit is connected to the feed end of the mechanical activation unit, and is used to feed the potassium feldspar raw material crushed to a predetermined particle size into the mechanical activation unit for surface lattice defect control.

[0010] The discharge end of the mechanical activation unit is connected to the feed end of the solar concentrating flash thermal shock unit, and is used to transport the material that has undergone short-term mechanical activation to the solar concentrating flash thermal shock unit for flash thermal shock pre-activation.

[0011] The discharge end of the solar concentrating flash thermal shock unit is connected to the feed end of the calcium-based heterogeneous contact mixing unit, which is used to send the activated material after thermal shock into the calcium-based heterogeneous contact mixing unit, mix it with calcium-based particles, and form a heterogeneous solid-solid contact interface.

[0012] The discharge end of the calcium-based heterogeneous contact mixing unit is connected to the feed end of the low-temperature hydrothermal reactor, which is used to send the mixed material into the low-temperature hydrothermal reactor to complete calcium-induced lattice reconstruction and potassium release under medium-low temperature hydrothermal conditions.

[0013] The discharge end of the low-temperature hydrothermal reactor is connected to the feed end of the solid-liquid separation and recovery unit, which is used to send the reaction products into the solid-liquid separation and recovery unit for solid-liquid separation and product recovery.

[0014] As a further aspect of the present invention: the solar concentrating flash thermal shock unit includes a concentrating component, a fabric feeding device, a flash thermal shock reaction chamber, and a quenching device;

[0015] The fabric feeding device is located on the feed side of the flash thermal shock reaction chamber, and its feed end is connected to the discharge end of the mechanical activation unit. It is used to transport the activated material into the flash thermal shock reaction chamber in a thin-layer dispersed state.

[0016] The concentrating component is located on the photothermal input side of the flash thermal shock reaction chamber, forming a solar radiation energy transfer relationship with the flash thermal shock reaction chamber, and is used to concentrate solar radiation to apply transient thermal shock to the material inside the chamber.

[0017] The quenching device is located downstream of the discharge side of the flash thermal shock reaction chamber. Its inlet is connected to the material outlet of the flash thermal shock reaction chamber, and its outlet is connected to the calcium-based heterogeneous contact mixing unit. It is used to rapidly quench high-temperature materials to expand lattice defects.

[0018] As a further aspect of the present invention: the low-temperature hydrothermal reactor includes a reactor body, a stirring paddle, a pair of contact potential monitoring electrodes, and a heating jacket;

[0019] The reactor body is a closed pressure-bearing structure, with a mixing and activating material feeding port and a calcium-based feeding port at the top, and a reaction product discharge port at the bottom.

[0020] The stirring paddle is arranged inside the reactor along the central axis of the reactor body to promote continuous contact between calcium-based particles and activated potassium feldspar particles and to renew the heterogeneous contact interface.

[0021] The contact potential monitoring electrode extends at least partially into the material region inside the reactor body to monitor the interfacial electrochemical response during the contact process of heterogeneous particles.

[0022] The heating jacket covers the outer periphery of the reactor body and is used to provide heat to the reactor to maintain low-temperature hydrothermal reaction conditions.

[0023] As a further aspect of the present invention, it also includes a control and detection unit, which is connected to the mechanical activation unit, the solar concentrating flash thermal shock unit, the calcium-based heterogeneous contact mixing unit, and the low-temperature hydrothermal reactor, respectively, for collecting the operating parameters of each unit and performing linkage control of the process.

[0024] A synergistic activation method for low-temperature potassium release from potassium feldspar includes the steps of raw material crushing and post-reaction solid-liquid separation, and further includes the following steps:

[0025] S1 Short-time Mechanical Activation: The crushed potassium feldspar raw material is subjected to short-time mechanical activation treatment to construct initial lattice defects on the surface of the particles.

[0026] S2 Flash Thermal Shock Pre-activation: Concentrated solar energy is used to heat mechanically activated materials for a short time and then rapidly quench them. The difference in thermal expansion between mineral components is used to expand the crack network based on the initial defects.

[0027] S3 calcium-based heterogeneous contact activation: The quenched activation material is mixed with calcium-based particles to form a heterogeneous solid-solid contact interface, which reduces the calcium ion diffusion activation energy through interface charge transfer.

[0028] S4 Low-Temperature Hydrothermal Reconstruction: The mixture is placed under hydrothermal conditions of 180-260℃ for heat preservation and reaction, and potassium is released through calcium-induced lattice reconstruction.

[0029] As a further aspect of the present invention: in step S1, the short-time mechanical activation is carried out by high-speed vibration mill, planetary ball mill or stirring mill, and the activation process controls the density of lattice defects on the surface of the particles.

[0030] As a further aspect of the present invention: in step S2, the concentrated solar energy acts on the thin-layer material with a high energy flux density light spot, the peak temperature of the material surface is controlled at 600-900°C, and the thermal shock duration is from seconds to tens of seconds.

[0031] As a further aspect of the present invention: in step S3, the activated material and calcium-based particles are mixed at a calcium / potassium molar ratio of 1.5 to 3.0, and the degree of activation of the heterogeneous interface is monitored by the contact potential. After the interface potential tends to stabilize, the hydrothermal reaction stage is entered.

[0032] As a further aspect of the present invention: in step S4, the temperature of the hydrothermal reaction is controlled at 200-240°C, the reaction time is 1-4 hours, and the liquid-solid mass ratio of the reaction system is 3:1-6:1.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] Compared with high-temperature sintering methods above 1100℃ and conventional strong alkali submolten salt methods, this invention can achieve efficient activation and release of potassium in potassium feldspar under medium-low temperature hydrothermal conditions of 180-260℃, reducing dependence on high-temperature equipment and large amounts of strong alkali reagents, which is beneficial to reducing the total energy consumption of the system and the construction and maintenance costs of equipment.

[0035] Concentrated solar energy is used only to apply short-term thermal shock to thin-layer materials, rather than to maintain the overall high-temperature sintering state of the materials. This can significantly reduce the capacity requirements of the concentrated solar collector system, thereby reducing the initial investment and operating costs of the solar energy utilization system.

[0036] The two-stage synergistic pre-activation of short-term mechanical activation and concentrated solar flash thermal shock can achieve a higher lattice defect density than a single activation method, providing more channels for calcium ion diffusion and effectively shortening the time required for subsequent hydrothermal reactions.

[0037] The electrochemical effect of the heterogeneous interface between calcium-based particles and activated feldspar particles can reduce the activation energy required for calcium ion diffusion and ion exchange. This can increase the potassium release rate under the same calcium / potassium molar ratio and reduce the consumption of calcium-based materials while maintaining the target potassium release rate.

[0038] This device integrates a mechanical activation unit, a solar concentrating flash thermal shock unit, a calcium-based heterogeneous contact mixing unit, a low-temperature hydrothermal reactor, and a solid-liquid separation and recovery unit into a single system. It can support continuous or semi-continuous production and is particularly suitable for areas with abundant solar energy resources and concentrated potassium feldspar deposits, enabling the local sourcing and utilization of renewable energy. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of the synergistic activation method for low-temperature potassium release from potassium feldspar in an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the structure of the solar concentrating flash thermal shock unit in an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of the calcium-based heterojunction contact-low-temperature hydrothermal reactor structure in an embodiment of the present invention.

[0042] In the diagram: 0-Raw material crushing unit, 1-Mechanical activation unit, 2-Solar concentrating flash thermal shock unit, 3-Calcium-based heterogeneous contact mixing unit, 4-Low-temperature hydrothermal reactor, 5-Solid-liquid separation and recovery unit, 6-Solid residue, 7-Control and detection unit, 21-Concentrating component, 22-Material feeding device, 23-Flash thermal shock reaction chamber, 24-Temperature monitoring device, 25-Quenching device, 41-Reaction vessel body, 42-Agitator, 43-Calcium-based feed port, 44-Contact potential monitoring electrode pair, 45-Heating jacket, 46-Temperature and pressure detection component, 47-Mixed activated material feed port, 48-Reaction product discharge port. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0045] Please see Figure 1 The present invention provides a synergistic activation device for low-temperature potassium release from potassium feldspar, comprising a raw material crushing unit 0, a mechanical activation unit 1, a solar concentrating flash thermal shock unit 2, a calcium-based heterogeneous contact mixing unit 3, a low-temperature hydrothermal reactor 4, a solid-liquid separation and recovery unit 5, and a control and detection unit 7.

[0046] The discharge end of the raw material crushing unit 0 is connected to the feed end of the mechanical activation unit 1, and is used to feed the potassium feldspar raw material crushed to a predetermined particle size into the mechanical activation unit 1 for surface lattice defect control.

[0047] The discharge end of the mechanical activation unit 1 is connected to the feed end of the solar concentrating flash thermal shock unit 2, and is used to transport the material that has undergone short-term mechanical activation to the solar concentrating flash thermal shock unit 2 for flash thermal shock pre-activation.

[0048] The discharge end of the solar concentrating flash thermal shock unit 2 is connected to the feed end of the calcium-based heterogeneous contact mixing unit 3, which is used to send the activated material after thermal shock into the calcium-based heterogeneous contact mixing unit 3, mix it with calcium-based particles, and form an initial heterogeneous solid-solid contact interface.

[0049] The discharge end of the calcium-based heterogeneous contact mixing unit 3 is connected to the feed end of the low-temperature hydrothermal reactor 4, which is used to send the mixed material into the low-temperature hydrothermal reactor 4 to complete the calcium-induced lattice reconstruction and potassium release reaction under medium and low temperature hydrothermal conditions.

[0050] The discharge end of the low-temperature hydrothermal reactor 4 is connected to the feed end of the solid-liquid separation and recovery unit 5, which is used to send the reaction products into the solid-liquid separation and recovery unit 5 for solid-liquid separation and product recovery. The liquid phase separated by the solid-liquid separation and recovery unit 5 is sent to the subsequent potassium extraction process, and the separated solid residue 6 can be used for calcium source regeneration or resource utilization.

[0051] The control and detection unit 7 is connected to the mechanical activation unit 1, the solar concentrating flash thermal shock unit 2, the calcium-based heterogeneous contact mixing unit 3, and the low-temperature hydrothermal reactor 4 respectively. It is used to collect the operating parameters of each unit and perform linkage control of the process. The control and detection unit 7 preferably integrates the functions of multi-parameter acquisition and linkage control such as temperature, pressure, contact potential and meteorological parameters (such as irradiance) to realize the dynamic adjustment of process parameters under the condition of solar energy resource fluctuation.

[0052] like Figure 2As shown, the solar concentrating flash thermal shock unit 2 is disposed between the mechanical activation unit 1 and the calcium-based heterogeneous contact mixing unit 3, and includes a concentrating component 21, a fabric feeding device 22, a flash thermal shock reaction chamber 23, a temperature monitoring device 24, and a quenching device 25.

[0053] The feeding device 22 is located on the feed side of the flash thermal shock reaction chamber 23. Its feed end is connected to the discharge end of the mechanical activation unit 1, and its discharge end is connected to the material inlet of the flash thermal shock reaction chamber 23. It is used to receive the potassium feldspar activated material after being processed by the mechanical activation unit 1, and to continuously convey the activated material into the flash thermal shock reaction chamber 23 in a thin layer, granular dispersion, or fluidized state. The feeding device 22 can be a vibrating feeder or a fluidizing feeder. The thickness of the material layer and the conveying speed are controlled by adjusting the vibration frequency or the fluidizing gas velocity. It is a conventional feeding device in the field of powder processing.

[0054] The concentrating module 21 is disposed on the photothermal input side of the flash thermal shock reaction chamber 23, preferably above the flash thermal shock reaction chamber 23 and corresponding to the light-receiving window of the flash thermal shock reaction chamber 23. It forms a solar radiation energy transfer relationship with the flash thermal shock reaction chamber 23, and is used to concentrate solar radiation to the material heating area within the flash thermal shock reaction chamber 23. This causes the potassium feldspar material, which has undergone mechanical activation and formed lattice defects, to rapidly heat up and undergo transient thermal shock in a short time, further inducing lattice stress, expanding microcracks, and increasing surface active sites. The concentrating module 21 can be a concentrating mirror field or a Fresnel lens group, both of which are conventional concentrating heat collection components in the field of concentrated solar energy. The energy flux density of the light spot can be controlled by adjusting the concentration factor.

[0055] Temperature monitoring device 24 is installed on the monitoring side of the flash thermal shock reaction chamber 23, with its detection direction facing the heated material area within the chamber. It is used for non-contact detection of the material surface temperature, temperature change rate, and temperature distribution during the thermal shock process, and transmits the detection signal to the control and detection unit 7 to adjust the focusing intensity, material conveying speed, and material residence time within the heated area. Temperature monitoring device 24 can be an infrared thermometer or a thermal imaging monitoring device, both of which are standard detection devices in the field of high-temperature non-contact temperature measurement.

[0056] The quenching device 25 is located downstream of the discharge side of the flash thermal shock reaction chamber 23. Its inlet is connected to the material outlet of the flash thermal shock reaction chamber 23, and its outlet is connected to the calcium-based heterogeneous contact mixing unit 3. It is used to rapidly cool the high-temperature material after flash thermal shock treatment, causing the material to undergo precipitous cooling after rapid heating. This utilizes the thermal contraction differences between different mineral components and crystal orientations to further expand the original lattice defects and microcracks. The pre-activated material after quenching is discharged from the quenching device 25 and transported to the calcium-based heterogeneous contact mixing unit 3. The quenching device 25 can be an air-cooled cooler or a water mist quencher, achieving rapid cooling of the material through cold air, atomized water, or a combination of both. It is a conventional device for cooling high-temperature powders.

[0057] Thus, the solar concentrating flash thermal shock unit 2 forms a continuous material handling path between the mechanical activation unit 1 and the calcium-based heterogeneous contact mixing unit 3: mechanical activation unit 1 → material feeding device 22 → flash thermal shock reaction chamber 23 → quenching device 25 → calcium-based heterogeneous contact mixing unit 3; simultaneously, the concentrating module 21 provides transient solar thermal energy to the flash thermal shock reaction chamber 23, and the temperature monitoring device 24 monitors the thermal shock process in real time, forming a solar flash thermal shock pre-activation process in which material conveying, concentrating heating, temperature monitoring, and rapid quenching are mutually coordinated. This unit increases the lattice defect density by short-term thermal shock rather than maintaining a high temperature throughout, which can significantly reduce the capacity requirements and operating energy consumption of the concentrating solar collector system, unlike the traditional solar energy utilization mode that maintains the overall sintering temperature.

[0058] like Figure 3 As shown, the low-temperature hydrothermal reactor 4 includes a reactor body 41, a stirring paddle 42, a calcium-based feed port 43, a contact potential monitoring electrode pair 44, a heating jacket 45, a temperature and pressure detection component 46, a mixed activation material feed port 47, and a reaction product discharge port 48.

[0059] The reactor body 41 is a closed, pressure-bearing structure, forming the main space for material mixing, heterogeneous interface contact, and low-temperature hydrothermal reaction. A heating jacket 45 is located on the outer periphery of the reactor body 41, at least covering its side walls and bottom. It provides heat to the interior of the reactor body 41 via a heat transfer medium or electric heating, maintaining the materials inside the vessel under the set low-temperature hydrothermal reaction conditions. The heating jacket 45 is equipped with a heat transfer medium circulation pipeline or electric heating elements, representing a standard heating configuration for pressure-bearing reactors.

[0060] The calcium-based feed port 43 and the mixed-activated material feed port 47 are respectively located on the upper part of the reactor body 41 and are connected to the interior of the reactor body 41. The calcium-based feed port 43 is used to add calcium-based particles into the reactor body 41, while the mixed-activated material feed port 47 is used to receive the mixed material output from the preceding calcium-based heterogeneous contact mixing unit 3, allowing the materials to continuously contact and react inside the reactor body 41. The calcium-based particles can be CaO or Ca(OH)2 particles, both of which can be used as calcium source additives for calcium-induced lattice reconstruction.

[0061] The stirring paddle 42 is disposed inside the reactor body 41 and arranged along the central axis of the reactor body 41. Its stirring shaft extends into the reactor body 41 from the top and the stirring blades are located in the material area of ​​the middle and lower part of the reactor body 41. The stirring paddle 42 is used to make the calcium-based particles and the activated potassium feldspar particles continuously collide, rub, contact and redisperse, promote the formation and renewal of the heterogeneous contact interface between the two types of solid particles, and improve the uniformity of mass transfer and calcium-induced lattice deconstruction-reconstruction process in the hydrothermal medium.

[0062] The contact potential monitoring electrode pair 44 is disposed on the side of the reactor body 41 and extends at least partially into the material contact area inside the reactor body 41. It is used to monitor the interfacial potential difference, potential fluctuation or related electrochemical response generated between calcium-based particles and mechanically activated and thermally activated potassium feldspar particles during contact, friction and reaction. The contact potential monitoring electrode pair 44 is connected to the external control and detection unit 7 to evaluate the contact state of the heterogeneous interface and the changes in the reaction process based on the monitoring results, and to provide feedback for the control of process parameters such as stirring intensity and contact time.

[0063] The temperature and pressure detection component 46 is located on the side of the reactor body 41, with its detection end extending into the reactor body 41. It is used to detect the reaction temperature and / or pressure inside the reactor in real time and is connected to the control and detection unit 7 via a signal connection. The control and detection unit 7 adjusts the heating power of the heating jacket 45 or the flow rate of the heat transfer medium based on the feedback signal from the temperature and pressure detection component 46, maintaining a preset low-temperature hydrothermal reaction condition inside the reactor body 41. The temperature and pressure detection component 46 can be a temperature sensor, a pressure sensor, or an integrated temperature and pressure transmitter, all of which are standard detection components for pressure-bearing reaction equipment.

[0064] The reaction product outlet 48 is located at the bottom of the reactor body 41 and is connected to the interior of the reactor body 41. It is used to discharge the reaction product containing liquid potassium components and calcium-induced reconstructed solid phase after the low-temperature hydrothermal reaction is completed. The discharged reaction product is further transported to the solid-liquid separation and recovery unit 5. After solid-liquid separation, the liquid phase is used for potassium extraction, concentration, or product preparation, while the solid phase is used for calcium source regeneration, recycling, or further utilization as silicon- or calcium-containing materials, depending on its composition. The solid-liquid separation and recovery unit 5 integrates solid-liquid separation equipment, potassium enrichment equipment, and solid phase treatment equipment. The solid-liquid separation can adopt conventional solid-liquid separation methods such as plate and frame filtration and centrifugal separation. Potassium recovery can adopt conventional processes such as evaporation crystallization and chemical reaction to prepare potassium fertilizer. Solid phase calcium regeneration can adopt conventional methods such as calcination or carbonation treatment.

[0065] Thus, the low-temperature hydrothermal reactor 4 establishes the following continuous processing relationship: the mixed activated potassium feldspar material enters the reactor body 41 through the mixed activated material feed port 47, and calcium-based particles can be added to the reactor body 41 through the calcium-based feed port 43. Under the action of the stirring paddle 42, continuous contact and interface renewal of heterogeneous particles are achieved. At the same time, the electrochemical response of the interface is monitored by the contact potential monitoring electrode 44, and the low-temperature hydrothermal reaction conditions are maintained by the temperature and pressure detection component 46 and the heating jacket 45. After the reaction is completed, the material is finally discharged through the reaction product outlet 48. This structure integrates calcium-based heterogeneous interface contact, contact electrochemical monitoring, mechanical stirring enhancement, and low-temperature hydrothermal calcium-induced reconstruction in the same reactor. This allows the potassium feldspar, which has been pre-activated by mechanical defect regulation and thermal shock, to undergo further lattice deconstruction and silicon-aluminum framework reconstruction under the action of calcium-based particles, promoting the migration of potassium elements from the original feldspar lattice to the liquid phase or extractable form.

[0066] This invention also provides a synergistic activation method for low-temperature potassium release from potassium feldspar, implemented using the aforementioned apparatus, and specifically includes the following steps:

[0067] Step 1: Raw material crushing and short-term mechanical activation

[0068] Potassium feldspar raw material is crushed to 100-325 mesh by raw material crushing unit 0 and then sent to mechanical activation unit 1 for short-term mechanical activation treatment. Mechanical activation unit 1 can be a high-speed vibratory mill, planetary ball mill or stirred mill. By controlling the grinding speed, ball-to-material ratio and treatment time, the activation process focuses on regulating the lattice defect density of the particle surface and near-surface, rather than continuously reducing the particle size. The activation energy consumption is controlled within the process window where the defect density is close to saturation and particle agglomeration has not yet occurred significantly.

[0069] This step generates initial lattice defects such as dislocations, microcracks, and amorphous layers on the surface of potassium feldspar particles through short-term mechanical activation, providing a basic channel for subsequent thermal shock crack propagation and calcium ion diffusion. Compared with long-term fine grinding, this method can effectively avoid the cancellation of activation effect caused by particle agglomeration and reduce the mechanical activation energy consumption per unit of material.

[0070] Preferably, the mechanical activation unit 1 uses a high-speed vibration mill, with a processing time of 10 to 20 minutes and a ball-to-material ratio of 8:1 to 15:1.

[0071] Step 2: Pre-activation by solar concentrating flash thermal shock

[0072] The activated material obtained in step one is conveyed in a thin, dispersed state to the flash thermal shock reaction chamber 23 through the feeding device 22. The solar energy is focused by the focusing component 21 to form a high energy flux density light spot, so that the surface of the material is rapidly heated to the predetermined peak temperature in a short time of seconds to tens of seconds. Then, the material is rapidly cooled by the quenching device 25, forming a heating mode of thermal shock rather than overall high temperature maintenance.

[0073] This step utilizes the difference in thermal expansion coefficients between different mineral phases within potassium feldspar and between the initial defect region formed in step one and the lattice matrix. By leveraging the thermal stress generated by rapid temperature rises and falls, it further expands the crack network, increases the specific surface area, and generates more unsaturated dangling bonds based on the initial defects. Since solar energy is only used to apply short-term thermal shock to thin-layer materials rather than maintaining the entire material in a high-temperature sintering state, the required capacity and operating energy consumption of the concentrating solar thermal system are significantly lower than existing schemes that use solar energy as a high-temperature heat source.

[0074] Preferably, the focusing component 21 employs a Fresnel lens focusing method, with a beam energy flux density of 500–1500 kW / m². 2 The peak temperature of the material surface is controlled at 600-900℃, and the duration of thermal shock is 5-30 seconds.

[0075] Step 3: Electrochemical activation of calcium-based heterojunction contact

[0076] The activated material processed in step two is fed into the calcium-based heterogeneous contact mixing unit 3, where it is initially mixed with calcium-based particles at a predetermined calcium / potassium molar ratio to form an initial heterogeneous contact interface. The mixture is then fed into the low-temperature hydrothermal reactor 4 through the mixed activated material feed port 47, where the solid-solid contact interface is continuously renewed under the continuous action of the stirring paddle 42. Because the feldspar particles activated in steps one and two have numerous defect-induced surface states and unsaturated dangling bonds, there is a significant surface potential difference between them and the calcium-based particle surface. During close contact, a heterogeneous interface contact electrochemical effect occurs, resulting in interfacial charge transfer. This effect can be monitored in real time by contact potential monitoring electrodes inserted into the material bed 44 to characterize the degree of contact activation between the activated material and the calcium source particles, and can serve as feedback for process parameter control. The aforementioned interfacial charge transfer forms a local electric field near the particle contact point, which reduces the activation energy required for calcium ions to diffuse into the feldspar lattice and exchange with potassium ions, creating more favorable interfacial kinetic conditions for calcium-induced reconstruction in the subsequent hydrothermal stage.

[0077] Preferably, the potential difference increment ΔV after the start of contact is used as the characterization parameter. When ΔV reaches the critical value ΔVc obtained by pre-experiment calibration, and the potential change amplitude does not exceed 5% to 10% of the peak value within 5 to 10 minutes, or the potential change rate is lower than the preset stability threshold, the heterogeneous interface contact activation is determined to be basically sufficient.

[0078] Preferably, the calcium / potassium molar ratio is 1.5 to 3.0.

[0079] Step 4: Medium- and low-temperature hydrothermal calcium-induced reconstruction

[0080] The calcium-feldspar mixture obtained in step three, along with an appropriate amount of water, is mixed in a low-temperature hydrothermal reactor 4. With the cooperation of the temperature and pressure detection component 46 and the heating jacket 45, the temperature inside the reactor is controlled within the range of 180–260°C, corresponding to an autogenous pressure of approximately 1–4.5 MPa. The reaction is maintained at this temperature for a certain period. Under the synergistic effect of the aforementioned lattice defect regulation and interfacial contact electrochemical effect, calcium ions diffuse rapidly along the crack network and defect channels into the feldspar lattice, undergoing exchange / substitution reactions with potassium ions. This disrupts the feldspar aluminosilicate framework, generating calcium-containing silicate / hydration products. Simultaneously, potassium is released in ionic form into the liquid phase or transformed into water-soluble potassium compounds that accumulate on the surface of the solid-phase products.

[0081] This step can complete calcium-induced feldspar lattice reconstruction and potassium release under medium-low temperature conditions of 180-260℃. Compared with the high-temperature sintering method, it significantly reduces the reaction temperature and equipment requirements. Compared with the submolten salt method, it does not require a large amount of strong alkali and a supporting alkali recovery system, which can effectively reduce process operating costs and equipment corrosion risks.

[0082] Preferably, the reaction temperature is 200–240°C, the reaction time is 1–4 hours, and the liquid-to-solid ratio, i.e., the mass ratio of water to calcium-feldspar mixture, is 3:1–6:1.

[0083] Step 5: Solid-liquid separation and product processing

[0084] After the reaction products are discharged through the reaction product outlet 48, they enter the solid-liquid separation and recovery unit 5. After solid-liquid separation, the liquid phase can be evaporated and crystallized, or reacted with sulfuric acid / sulfate to prepare water-soluble potassium fertilizer products such as potassium sulfate. The solid residue 6 is mainly composed of calcium silicate substances, which can be used as cement admixtures or soil conditioners for resource utilization. Some of the calcium components can be calcined or carbonized and regenerated before being returned to the calcium-based heterogeneous contact mixing unit 3 for recycling, so as to reduce calcium consumption costs.

[0085] The technical effects of the present invention will be further illustrated below through a set of specific embodiments:

[0086] 1.0 kg of potassium feldspar powder with a K2O content of about 12% was selected, crushed to about 200 mesh by raw material crushing unit 0, and fed into mechanical activation unit 1, i.e., high-speed vibration mill. At a ball-to-material ratio of 10:1, it was subjected to short-term mechanical activation treatment for about 15 minutes under the conditions of vibration frequency of about 20-35 Hz and amplitude of about 3-8 mm, to obtain activated feldspar powder with a surface rich in dislocations and microcracks.

[0087] The activated material is fed into the flash thermal shock reaction chamber 23 in a thin layer of about 1-3 mm thickness via the feeding device 22. Solar energy is focused onto the surface of the material by the focusing component 21, i.e., the Fresnel lens group, and the energy flux density of the light spot is controlled to be about 1000 kW / m². 2 The material surface is heated to a peak temperature of approximately 700-800°C within about 10-20 seconds, and then rapidly cooled to near room temperature by the quenching device 25, i.e., the air-cooled quenching device, to obtain a further activated material after thermal shock treatment.

[0088] The activated material and CaO particles were initially mixed in the calcium-based heterogeneous contact mixing unit 3 at a calcium / potassium molar ratio of approximately 2.0. The mixture was then sent to a low-temperature hydrothermal reactor 4, where an appropriate amount of water was added, resulting in a liquid-to-solid ratio of approximately 4:1. Under the action of the heating jacket 45, the temperature inside the reactor was controlled at approximately 220°C, corresponding to a self-generated pressure of approximately 2.3 MPa. The reaction was maintained at this temperature for approximately 2 hours. During the reaction, the change in the potential at the calcium-feldspar contact interface was monitored by the contact potential monitoring electrode 44, and the internal working conditions of the reactor were monitored by the temperature and pressure detection component 46.

[0089] After the reaction, the product is discharged through the reaction product outlet 48 and sent to the solid-liquid separation and recovery unit 5 for solid-liquid separation. The liquid phase can be further evaporated and crystallized or reacted with sulfuric acid to prepare potassium sulfate. The solid residue 6 can be used as a cement admixture and other resources, and some of the calcium components can be calcined and recycled. Testing showed that the potassium release rate of the synergistic method described in this embodiment is greater than 90%, significantly reducing energy consumption compared to the high-temperature sintering method (80% energy saving) and 30% compared to the molten salt method, without requiring NaOH or a corresponding alkali recovery system.

[0090] It should be noted that, in this invention, unless otherwise explicitly specified and limited, the terms "sliding," "rotating," "fixed," and "equipped" should be interpreted broadly. For example, they can refer to welded connections, bolted connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0091] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A synergistic activation device for low-temperature potassium release from potassium feldspar, comprising a raw material crushing unit (0) and a solid-liquid separation and recovery unit (5), characterized in that, It also includes a mechanical activation unit (1), a solar concentrating flash thermal shock unit (2), a calcium-based heterogeneous contact mixing unit (3), and a low-temperature hydrothermal reactor (4). The discharge end of the raw material crushing unit (0) is connected to the feed end of the mechanical activation unit (1) for feeding potassium feldspar raw material crushed to a predetermined particle size into the mechanical activation unit (1) for surface lattice defect control. The discharge end of the mechanical activation unit (1) is connected to the feed end of the solar concentrating flash thermal shock unit (2) to transport the material that has been mechanically activated for a short time to the solar concentrating flash thermal shock unit (2) for flash thermal shock pre-activation. The discharge end of the solar concentrating flash thermal shock unit (2) is connected to the feed end of the calcium-based heterogeneous contact mixing unit (3) to send the activated material after thermal shock into the calcium-based heterogeneous contact mixing unit (3) to mix with calcium-based particles and form a heterogeneous solid-solid contact interface. The discharge end of the calcium-based heterogeneous contact mixing unit (3) is connected to the feed end of the low-temperature hydrothermal reactor (4) to send the mixed material into the low-temperature hydrothermal reactor (4) to complete calcium-induced lattice reconstruction and potassium release under medium-low temperature hydrothermal conditions. The discharge end of the low-temperature hydrothermal reactor (4) is connected to the feed end of the solid-liquid separation and recovery unit (5) to send the reaction products into the solid-liquid separation and recovery unit (5) for solid-liquid separation and product recovery.

2. The synergistic activation device for low-temperature potassium release from potassium feldspar according to claim 1, characterized in that, The solar concentrating flash thermal shock unit (2) includes a concentrating component (21), a fabric feeding device (22), a flash thermal shock reaction chamber (23), and a quenching device (25). The fabric feeding device (22) is located on the feeding side of the flash thermal shock reaction chamber (23), and its feeding end is connected to the discharging end of the mechanical activation unit (1) to transport the activated material into the flash thermal shock reaction chamber (23) in a thin-layer dispersed state. The concentrating component (21) is located on the photothermal input side of the flash thermal shock reaction chamber (23) and forms a solar radiation energy transfer relationship with the flash thermal shock reaction chamber (23) to concentrate solar radiation to apply transient thermal shock to the material inside the chamber; The quenching device (25) is located downstream of the discharge side of the flash thermal shock reaction chamber (23). Its inlet is connected to the material outlet of the flash thermal shock reaction chamber (23), and its outlet is connected to the calcium-based heterogeneous contact mixing unit (3). It is used to rapidly quench high-temperature materials to expand lattice defects.

3. The synergistic activation device for low-temperature potassium release from potassium feldspar according to claim 1, characterized in that, The low-temperature hydrothermal reactor (4) includes a reactor body (41), a stirring paddle (42), a pair of contact potential monitoring electrodes (44), and a heating jacket (45). The reactor body (41) is a closed pressure-bearing structure. It is provided with a mixing and activating material feeding port (47) and a calcium-based feeding port (43) at the top, and a reaction product discharge port (48) at the bottom. The stirring paddle (42) is arranged inside the reactor along the central axis of the reactor body (41) to promote continuous contact between calcium-based particles and activated potassium feldspar particles and to renew the heterogeneous contact interface. The contact potential monitoring electrode pair (44) extends at least partially into the material region inside the reactor body (41) to monitor the interfacial electrochemical response during the contact process of heterogeneous particles. The heating jacket (45) covers the outer periphery of the reactor body (41) and is used to provide heat to the reactor to maintain low-temperature hydrothermal reaction conditions.

4. The synergistic activation device for low-temperature potassium release from potassium feldspar according to claim 1, characterized in that, It also includes a control and detection unit (7), which is connected to the mechanical activation unit (1), the solar concentrating flash thermal shock unit (2), the calcium-based heterogeneous contact mixing unit (3) and the low-temperature hydrothermal reactor (4) respectively, and is used to collect the operating parameters of each unit and perform linkage control of the process.

5. A synergistic activation method for low-temperature potassium release from potassium feldspar, comprising the steps of raw material crushing and post-reaction solid-liquid separation, characterized in that, It also includes the following steps: S1 Short-time Mechanical Activation: The crushed potassium feldspar raw material is subjected to short-time mechanical activation treatment to construct initial lattice defects on the surface of the particles. S2 Flash Thermal Shock Pre-activation: Concentrated solar energy is used to heat mechanically activated materials for a short time and then rapidly quench them. The difference in thermal expansion between mineral components is used to expand the crack network based on the initial defects. S3 calcium-based heterogeneous contact activation: The quenched activation material is mixed with calcium-based particles to form a heterogeneous solid-solid contact interface, which reduces the calcium ion diffusion activation energy through interface charge transfer. S4 Low-Temperature Hydrothermal Reconstruction: The mixture is placed under hydrothermal conditions of 180-260℃ for heat preservation and reaction, and potassium is released through calcium-induced lattice reconstruction.

6. The synergistic activation method for low-temperature potassium release from potassium feldspar according to claim 5, characterized in that, In step S1, the short-term mechanical activation is carried out using a high-speed vibration mill, planetary ball mill, or stirring mill, and the activation process controls the density of lattice defects on the particle surface.

7. The synergistic activation method for low-temperature potassium release from potassium feldspar according to claim 5, characterized in that, In step S2, the concentrated solar energy acts on the thin material with a high energy flux density light spot, the peak temperature of the material surface is controlled at 600-900℃, and the thermal shock duration is from seconds to tens of seconds.

8. The synergistic activation method for low-temperature potassium release from potassium feldspar according to claim 5, characterized in that, In step S3, the activated material and calcium-based particles are mixed at a calcium / potassium molar ratio of 1.5 to 3.

0. The degree of activation of the heterogeneous interface is monitored by the contact potential. After the interface potential stabilizes, the hydrothermal reaction stage begins.

9. The synergistic activation method for low-temperature potassium release from potassium feldspar according to claim 5, characterized in that, In step S4, the temperature of the hydrothermal reaction is controlled at 200-240℃, the reaction time is 1-4 hours, and the liquid-solid mass ratio of the reaction system is 3:1-6:1.

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