Surface modified anti-agglomerated sodium pyrocatecholate synthesis process

Abstract

The application relates to the technical field of inorganic chemical synthesis, and discloses a surface-modified anti-agglomerated sodium pyroantimonate synthesis process, which comprises the following steps: constructing a sodium antimonite homogeneous phase bottom liquid, utilizing online optical turbidity monitoring to accurately lock the crystal nucleus initial growth kinetics window, pulsing a multi-tooth hydroxyl carboxylic acid salt modifier into the interval where the turbidity is first increased to 5 NTU to 15 NTU, inhibiting hydrogen bond agglomeration through a chemical bonding steric layer and synchronously complexing and separating metal impurities, and obtaining sodium pyroantimonate solids through controlled growth and solid-liquid separation, the application avoids the micro basis of hydrogen bond hard agglomeration between crystal grains, the obtained product is monodisperse spherical without physical crushing, impurity ions are locked in liquid phase, and the product purity and photovoltaic glass clarification efficiency are improved.

Description

Technical Field

[0001] This invention relates to a surface-modified anti-agglomeration sodium pyroantimonate synthesis process, belonging to the field of inorganic chemical synthesis technology. Background Technology

[0002] Currently, industrial production mainly employs the antimony trioxide liquid-phase oxidation method, which uses hydrogen peroxide in an alkaline sodium hydroxide medium to oxidize trivalent antimony to pentavalent antimony, resulting in the supersaturated precipitation of sodium pyrosantimonate crystals. This process has mild reaction conditions and high yield, making it the mainstream route for large-scale preparation of sodium pyrosantimonate. However, with the increasing demands for light transmittance and high-temperature melting dispersion in the photovoltaic glass industry, the limitations of existing liquid-phase oxidation processes in terms of kinetic control are becoming increasingly apparent. The hexahydroxyantimonate octahedral units in the sodium pyrosantimonate crystal structure have extremely high surface chemical activity. The oxidation reaction triggers explosive nucleation in the early stages, and the hydroxyl groups on the surface of the newly formed crystal nuclei readily associate through hydrogen bonding. This adhesion during the liquid-phase growth stage leads to the formation of dense, hard agglomerates that are extremely difficult to break down during the subsequent drying process, severely affecting the uniformity of microscopic dispersion of the product in the glass melt. At the same time, trace amounts of iron and lead transition metal impurities in industrial-grade raw materials are easily adsorbed and encapsulated by high-energy surfaces during the rapid crystal growth process, entering lattice defects and forming impurities that are difficult to remove through conventional surface washing, resulting in color deviations in the final product.

[0003] To address the issues of product agglomeration and purity, existing technologies primarily employ back-end physical pulverization or conventional chemical modification. While airflow pulverization can reduce the average particle size, it cannot repair grain boundary defects caused by micro-agglomeration and easily introduces mechanical wear impurities that damage crystal integrity. Regarding chemical modification, if an organic dispersant is added directly before the reaction, the presence of excessive strong oxidants and high temperatures in the reaction system can easily cause the dispersant to oxidize and decompose, leading to carbon residue. If the dispersant is added after the reaction is complete, the hard hydrogen-bonded agglomerate structure between grains has solidified, and the modifier can only physically adsorb onto the outer surface of the agglomerates, unable to penetrate the interior to break the rigid bonds. Simply relying on conventional chemical additives or catalysts makes it difficult to simultaneously achieve both oxidation efficiency and micro-agglomeration. The morphology is precisely controlled. For example, Chinese invention patent CN86101108A discloses a wet process for producing sodium pyroantimonate from antimony concentrate. This scheme proposes to introduce hydroquinone and copper salt catalysts into the oxidation process to promote the reaction and improve product quality. The technology focuses on macroscopic element separation and oxidation conversion rate, but lacks a real-time feedback mechanism for the microscopic state of the reaction system. Traditional processes cannot accurately capture the microsecond-level kinetic window of the initial crystal nucleus formation. As a result, additives only play a role after hydrogen bonding occurs in the crystal nucleus or after impurity ions are captured by the crystal lattice. This blind chemical intervention does not fundamentally establish a synchronous competition mechanism between crystal growth and deep lattice impurity removal, making it difficult for the monodispersity and intrinsic purity of the final product to meet the stringent requirements of modern high-end photovoltaic glass for clarifying agents.

[0004] Therefore, the technical problem to be solved by this invention is to establish a new process that can precisely intervene in the nucleation kinetics and simultaneously achieve in-situ control of microstructure and lattice-level purification synthesis while maintaining the efficiency of the oxidation reaction. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: a surface-modified anti-agglomeration sodium pyroantimonate synthesis process, wherein the process is based on a nucleation kinetic window determined by online optical turbidity monitoring to perform pulsed chemical intervention, comprising the following steps:

[0006] Step S1: Construct a homogeneous sodium antimonylate bottom solution by dispersing antimony trioxide powder in an aqueous sodium hydroxide solution and carrying out a dissolution reaction at a temperature of 85°C to 95°C until the solution becomes a clear state with a transmittance of more than 99%. Filter to remove insoluble matter and keep the temperature of the filtrate constant at 55°C to 65°C to establish a homogeneous sodium antimonylate bottom solution with a turbidity baseline value of less than 1 NTU.

[0007] Step S2, crystal nucleus capture and pulse modification: Hydrogen peroxide solution is added to the homogeneous sodium antimonite substrate at a constant flow rate to initiate an oxidative crystallization reaction. The real-time turbidity of the reaction system is monitored using an online turbidity sensor at a frequency of not less than 1 Hz. When the turbidity of the reaction system rises from the baseline value to the range of 5 NTU to 15 NTU for the first time, the modifier injection action is triggered. A multidentate hydroxycarboxylate solution is injected into the reaction system in one go within 10 to 30 seconds. The molar ratio of multidentate hydroxycarboxylate to antimony element is 1:100 to 1:50.

[0008] Step S3, steric hindrance-guided growth and separation: After the modifier injection is completed, the remaining hydrogen peroxide solution is added until the oxidation reaction endpoint is reached, and the reaction is maintained with stirring for 1.5 to 2.5 hours. The multidentate hydroxycarboxylate forms a chemically bonded steric layer on the surface of the new crystal nuclei and simultaneously complexes metal impurity ions in the liquid phase. After the reaction is completed, the resulting slurry is subjected to solid-liquid separation, the liquid phase containing the metal impurity complex is removed, the solid product is collected and washed with water and dried at 105 to 120 degrees Celsius to obtain sodium antimonate pyroantimonate solid.

[0009] Preferably, the multidentate hydroxycarboxylate solution is selected from sodium tartrate aqueous solution or sodium citrate aqueous solution; in step S2, the mass percentage concentration of the multidentate hydroxycarboxylate solution is 15% to 25%, and the solution is preheated to the same temperature as the reaction system before injection; the modifier injection is performed by a high-pressure feeding device, which provides turbulent mixing energy to the reaction system within an injection time of 10 to 30 seconds, so that the multidentate hydroxycarboxylate completes coordination and end-capping before the hydroxyl groups on the crystal nucleus surface undergo dehydration condensation reaction.

[0010] Preferably, in step S1, the initial concentration of the sodium hydroxide aqueous solution is controlled at 3.5 mol / L to 4.5 mol / L, the molar ratio of antimony trioxide to sodium hydroxide is 1:2.2 to 1:2.5, the duration of the dissolution reaction is 30 minutes to 60 minutes, and after filtering to remove insoluble matter, the step further includes adding deionized water to the filtrate to adjust the antimony concentration to 0.8 mol / L to 1.2 mol / L.

[0011] Preferably, in step S2, the modifier injection action satisfies the pulse feeding throughput intensity. The limiting conditions, among which, Defined as the ratio of the modifier injection rate to the total volume of the reaction system, and satisfying the following relationship: ,in, The amount of the injected polydentate hydroxycarboxylate, in moles; The total volume of the reaction system at the injection point is expressed in liters. The duration required to complete the injection, in seconds; pulse feed flux intensity. The limitation is used to ensure that the polydentate hydroxycarboxylate reaches the saturated adsorption concentration during the micro-mixing time before the Brownian motion collision of the crystal nucleus.

[0012] Preferably, in step S2, the flow rate of the hydrogen peroxide solution is controlled such that the induction period for the turbidity of the reaction system to rise from 1 NTU to 5 NTU is controlled between 5 minutes and 15 minutes; the online turbidity sensor adopts the scattered light turbidity measurement method, the measuring probe is placed at a depth of half the liquid surface below the reaction liquid, and the measuring wavelength is selected in the near-infrared range of 850 nm to 880 nm.

[0013] Preferably, in step S3, the stirring linear speed of the stirring reaction is set to 2.0 m / s to 3.0 m / s, and the steric hindrance directed growth process is carried out in an alkaline environment with a pH value of 10 to 12. In this pH range, the complexation stability constant of the polydentate hydroxycarboxylate for iron ions is greater than the adsorption equilibrium constant on the surface of sodium pyroantimonate crystals, thereby driving iron ions to migrate from the solid-liquid interface to the liquid phase bulk.

[0014] Preferably, the sodium pyroantimonate solid is a directly dried product without mechanical grinding or air jet milling; the average particle size D50 of the sodium pyroantimonate solid is 1 micrometer to 3 micrometers, and it appears as isotropic cubic or spherical monodisperse particles under a scanning electron microscope. The particle surface is coated with an organic carbon layer bonded by chemical bonding, and the content of the organic carbon layer is 0.2% to 0.5%.

[0015] Preferably, in step S3, the solid-liquid separation operation adopts centrifugal separation, and the centrifugal separation factor is controlled between 800 and 1200; the water washing operation is performed until the conductivity of the washing filtrate drops to below 20 microsiemens per centimeter; the drying operation adopts a programmed temperature rise mode, drying at 60 degrees Celsius to 80 degrees Celsius for 30 minutes to remove free water, and then heating to 105 degrees Celsius to 120 degrees Celsius for 60 minutes to solidify the surface coordination layer.

[0016] Preferably, before constructing the homogeneous sodium antimonyate substrate in step S1, a pretreatment step of antimony trioxide raw material is included, wherein antimony trioxide powder is ultrasonically dispersed in anhydrous ethanol for 10 to 20 minutes, filtered and dried to remove gases and impurities physically adsorbed on the surface of the raw material.

[0017] Preferably, the process is used to prepare a clarifying agent for ultra-white photovoltaic glass; the sodium pyroantimonate solid prepared by this process contains less than 20 parts per million of ferric oxide, and the sodium pyroantimonate solid generates microbubble flow through the thermal decomposition of the surface organic ligand layer during the primary stage of glass melting at 600 degrees Celsius to 800 degrees Celsius, which promotes the secondary dispersion of clarifying agent particles in the glass melt.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. In surface-modified anti-agglomeration sodium pyroantimonate, an online optical monitoring system is used to capture the initial nucleation window as the homogeneous solution transitions to a heterogeneous suspension. Within a specific turbidity threshold range, a multidentate ligand modifier is introduced. The functional groups of the modifier rapidly coordinate with antimony atoms on the surface of the nascent crystal nuclei, constructing a chemically bonded steric hindrance layer on the crystal nuclei surface. This layer occupies high-energy active sites in the early stages of growth, thermodynamically blocking the path of hard agglomerates formed by the dehydration condensation or hydrogen bonding of sodium pyroantimonate octahedral units. This allows the crystals to grow in an isotropic monodisperse mode within the confinement of the steric hindrance layer, eliminating the adhesion caused by direct contact between crystal grains in traditional processes. This allows the final product to achieve a well-flowable spherical or cubic micro-regular structure without relying on high-energy mechanical pulverization.

[0020] 2. Establish a mechanism for removing transition metal impurities by utilizing competitive coordination at the liquid-solid interface. During crystal growth, the difference between the complexation stability constant of iron and lead metal ions under alkaline conditions and the adsorption energy on the crystal surface is utilized to construct a liquid-phase enrichment potential trap for impurity ions. This allows free impurity ions to preferentially form stable water-soluble complexes with the liquid-phase modifier, reducing the adsorption of impurity ions at the crystal growth interface and their encapsulation into the sodium pyroantimonate lattice defects. The impurity removal process occurs simultaneously with the crystallization process, avoiding the limitation of conventional surface washing in removing intracrystalline encapsulated impurities and improving the spectral transmittance performance of the solid product in photovoltaic glass applications.

[0021] 3. The sodium pyroantimonate particles are prepared by chemically bonding a quantitative organic ligand layer to their surface. This composite structure enhances the graded response characteristics of the material during high-temperature glass melting. In the initial melting stage of the glass batch, the surface-bound organic ligands decompose upon heating to generate gas, forming a localized turbulent flow field in the melt micro-region. This promotes the secondary dispersion and deagglomeration of the clarifying agent particles in the viscous melt. The material's own structure induces a micro-dispersion mechanism, which, combined with the high specific surface area of ​​the monodisperse particles, improves the oxygen release efficiency and bubble capture ability of sodium pyroantimonate at high temperatures. This reduces optical defects in the glass caused by uneven distribution of the clarifying agent, meeting the process requirements of high-quality photovoltaic glass for raw material uniformity and reactivity. Attached Figure Description

[0022] Figure 1 This is a flowchart of the pulse-type surface-modified sodium pyroantimonate synthesis process for online turbidity monitoring according to the present invention.

[0023] Figure 2 This is a comparison chart showing the effects of different drying modes on the organic carbon layer content and specific surface area of ​​the product.

[0024] Figure 3 This is a hardware module and principle block diagram of the intelligent synthesis system for sodium pyroantimonate based on closed-loop control according to the present invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] A surface-modified anti-agglomeration synthesis process for sodium pyroantimonate includes four stages: homogeneous precursor construction, crystal nucleation kinetic window locking, pulsed competitive coordination intervention, and controlled growth and impurity separation. Utilizing online turbidity monitoring data as feedback signals, a multidentate ligand modifier is introduced within a defined nucleation and agglomeration time lag window to intervene in the crystal growth path and separate impurities through chemical regulation. In the homogeneous precursor construction stage, a thermodynamically stable homogeneous sodium antimonate solution is established. Antimony trioxide powder pretreated with anhydrous ethanol is added to an aqueous sodium hydroxide solution. to Dissolved within a temperature range, maintained at this temperature until antimony trioxide lattice dissociates and transforms into dissolved sodium antimonite. The endpoint of dissolution is determined by the change in the transmittance of the solution. When a sample of the solution is taken... The transmittance of wavelength light exceeds When complete dissolution is determined, the solution is filtered to remove silica and insoluble iron oxide impurities carried over from the raw material. The temperature of the filtrate is then reduced to and maintained at a constant temperature. to This temperature range is set to balance the oxidation reaction rate and the crystal growth rate. The probe of the online turbidity sensor is placed below the liquid surface to continuously monitor the turbidity of the system, establishing a reading less than [value missing]. The baseline value of turbidity.

[0027] During the nucleation kinetic window locking and pulse intervention stage, a turbidity threshold-based feeding strategy was employed to intercept the kinetic window. A concentration of sodium antimonylate was added to the homogeneous sodium antimony substrate at a constant flow rate. to The hydrogen peroxide solution initiates the oxidation of trivalent antimony to pentavalent antimony and the supersaturation precipitation of sodium pyroantimonate. During this period, the online turbidity sensor detects a concentration of at least [missing value]. Data was collected at a specific frequency, and when the turbidity value of the reaction system first increased from the baseline value and entered... to When the system is in the initial nucleation stage and a stable hydrogen bond network has not yet formed between the nuclei, the feeding device is started. Instant Within seconds, a preheated modifier solution is injected into the reactor in a single pulse. The modifier is either sodium tartrate or sodium citrate, and the amount added is controlled so that the molar ratio of the modifier to antimony is [value missing]. to The injection process meets the pulse feeding throughput requirements. The limiting conditions, namely ,in, The amount of the injected polydentate hydroxycarboxylate, in moles; The total volume of the reaction system at the injection point is expressed in liters. The duration required to complete the injection, measured in seconds, is a parameter that limits the concentration of the modifier at the local mixing scale to reach the saturation adsorption threshold, occupying active sites before the hydroxyl groups on the crystal nucleus surface undergo dehydration condensation.

[0028] During the controlled growth and impurity separation stage, the modifier intervenes and establishes a chemically bonded steric hindrance layer. The remaining hydrogen peroxide is then continuously added until the oxidation reaction is complete, maintaining the system in... Value to Stirring reaction under alkaline conditions Hours to During this initial stage, the multidentate ligands adsorbed on the crystal nucleus surface construct a physical isolation layer between the crystal grains. The crystals diffuse and grow through the ligand gaps, forming spherical or cubic monodisperse particles. Simultaneously, utilizing the difference in complexation stability constants of iron and lead transition metal ions by the functional groups of the modifier in alkaline media, tartrate or citrate ions preferentially complex free ions in the liquid phase. The reaction forms a water-soluble complex, blocking impurities from entering the crystal lattice. After the reaction is complete, the mother liquor containing the impurity complex is removed by centrifugation. The solid product is washed with deionized water until the conductivity of the filtrate is less than [value missing]. After 105 to Segmented drying yields sodium antimonate solid; the organic ligand layer on the surface is used in subsequent photovoltaic glass melting. to Interval thermal decomposition generates gases that promote secondary dispersion of particles in the melt.

[0029] Example 1: In the industrial melting of ultra-white photovoltaic glass, the uniformity of the dispersion of the clarifying agent in the glass melt directly determines the bubble retention rate and solar transmittance of the substrate. Faced with a high-viscosity glass melt environment, sodium pyroantimonate prepared by traditional processes has a hard agglomerate structure based on hydrogen bonds, making it difficult to achieve single-particle-level dispersion in the early stages of melting. This easily leads to excessively rapid local oxygen release and insufficient clarification of the surrounding area. Furthermore, trace iron impurities encapsulated within the crystal lattice can introduce irreversible color centers. To address this situation, the synthesis process described in the aforementioned specific embodiment is used for preparation; the system in... A completely transparent homogeneous sodium antimonite buffer solution was constructed under isothermal conditions to eliminate interference from existing solid particles. With the constant-rate addition of hydrogen peroxide, the online monitoring system detected a jump in turbidity from the baseline value to [value missing]. At that moment, the numerical indicator showed that primary sodium pyroantimonate nuclei had been generated within the system, but the critical density for forming a large-scale hydrogen bond network had not yet been reached. The system immediately performed a pulsed injection of the modifier. Within seconds, a preset dose of sodium tartrate solution is injected into the reactor. This operation utilizes the time difference between nucleation and aggregation, allowing high-concentration tartrate ions to chemically seal the surface of newly formed crystal nuclei through bidentate coordination bonds before the irreversible dehydration condensation of hydroxyl groups on the crystal nucleus surface occurs. Here, the 15-second injection operation refers to the total feeding cycle of the reactor at the macroscopic level. At the microscopic scale, the high-pressure jet injects the sodium tartrate solution into a high-shear flow field with extremely high turbulent kinetic energy, causing the characteristic size of the modifier droplets to be instantly torn to below the micrometer level by mechanical shear force. This significantly shortens the localized liquid-liquid microscopic mass transfer characteristic time to between 10 and 50 microseconds. This localized microscopic mass transfer rate is physically much faster than the microsecond to millisecond timescale of condensation or hydrogen bonding reactions of hydroxyl groups on the surface of the nascent crystal nucleus. This ensures that the multidentate hydroxycarboxylate ligand can preemptively locate on the high-energy active sites of the nascent crystal nucleus with an extremely high probability of molecular collisions, thus successfully trunculating the spontaneous path of hard aggregation in the physical time domain. To overcome the fluid circulation delay and high-shear micro-region space of the 200L macroscopic system... To address the contradiction in scale span between confined domains, this invention controls the flow acceleration rate of the hydrogen peroxide solution, ensuring that primary nucleation events in the macroscopic flow field do not erupt instantaneously, but rather evolve in batches at a controllable and delayed rate. Because the total amount of newly generated monodisperse nuclei in each batch in the macroscopic flow field is suppressed to a low molar concentration level, when they enter the high-shear region at the outer edge of the bottom turbine blade with the macroscopic fluid circulation, the local concentration of the modifier injected at high speed by the high-speed jet from the scaling-type pressure nozzle in this region is always maintained in a relatively extremely excessive state, between 12 m / s and 1... Driven by a high-speed jet of 5 m / s, the characteristic diffusion distance of the modifier molecules in the high-shear flow field is shortened to less than 20 nm, stabilizing the diffusion mass transfer time of its characteristic molecules within the range of 10 microseconds to 50 microseconds. Each batch of nascent crystal nuclei entering the high-shear micro-region can undergo no less than 100,000 high-frequency molecular collisions with the highly enriched modifier molecules within this extremely short time window. Thus, within the macroscopic fluid circulation cycle, adaptive instantaneous end-capping of all nascent crystal nuclei in the entire reactor phase is achieved through spatiotemporal decoupling.

[0030] This coordination layer, established within a specific kinetic window, exerts a dual synergistic effect. On one hand, the organic ligands on the crystal nucleus surface provide sufficient steric hindrance to counteract van der Waals forces and hydrogen bonds, allowing the crystal to maintain an isotropic, independent growth mode during subsequent growth and blocking the formation path of hard aggregates. On the other hand, the ligands' complexation ability for iron ions in an alkaline liquid environment is far greater than the ability of lattice defects to capture iron ions, thus locking iron impurities introduced by the raw materials into the mother liquor, achieving lattice-level purification. The resulting sodium pyroantimonate product, after being fed into a photovoltaic glass furnace, exhibits a surface organic ligand layer... to Controlled thermal decomposition occurs during the initial melting stage, generating a trace gas flow that disturbs the surrounding melt, driving the clarifying agent particles to achieve secondary dispersion in the viscous glass melt. This improves the uniformity of oxygen release and clarification efficiency. This secondary dispersion mechanism does not rely on the thermal expansion of the trace gas to push away the extremely viscous silicate melt in the macroscopic state over a long distance. Instead, it is achieved through the high-temperature in-situ vaporization of the organic coating layer at the interface between the particles. A uniformly distributed nanoscale microbubble sliding gasket is instantly constructed between the sodium pyroantimonate solid phase interface and the surrounding glass melt phase. The formation of this gas phase gasket changes the local contact mechanics, greatly reducing the microscopic interface friction coefficient between the solid particle surface and the high-viscosity melt. Furthermore, its micro-explosion rupture effect cuts off any remaining van der Waals adhesion between adjacent particles. This allows the originally adhered clarifying agent particles to depolymerize and slide under the extremely weak thermal convection shear force of the melt itself, thereby achieving microscale peeling and secondary homogenization dispersion with an extremely low physical energy threshold.

[0031] Example 2: To objectively and quantitatively verify the effectiveness of the synthesis process of this invention in improving the performance of sodium pyroantimonate products, and to determine the optimal working window for key process parameters, a pilot-scale verification platform based on a 200L enamel-lined reactor was constructed, with an integrated measurement accuracy of [missing information]. An online laser scattering turbidity monitoring system, and a response time of less than [time missing]. A high-precision pulse feeding device was used to ensure accurate reproduction of the nucleation kinetic window locking and pulsed competitive coordination intervention steps as defined in the claims. The antimony trioxide raw material used in the experiment had a purity of 99.8% and an average particle size of 1.5 mm. Sodium hydroxide is an industrial-grade ion-exchange membrane alkali; hydrogen peroxide concentration is 27.5%; before the oxidation reaction starts, in-situ baseline calibration of the online optical monitoring system is performed, including continuously acquiring the background scattered light signal of the homogeneous sodium antimonite bottom liquid under the set stirring speed and temperature field conditions, removing instantaneous peak values ​​of bubble disturbance or liquid surface fluctuation, and calculating the steady-state arithmetic mean to lock the system background turbidity. Crystal nucleus monitoring employs a real-time differential algorithm, and the monitored value is defined as the sum of the real-time acquired signal and the background turbidity. The difference, the net turbidity increment after moving average filtering. When the turbidity measurement window stabilized within the 5 NTU to 15 NTU range for the first three consecutive sampling cycles, the central control unit determined that the kinetic window was open and generated a modifier injection trigger command. Using this specific turbidity measurement window as the criterion for kinetic intervention is based on the previously developed in-situ optical inversion verification. Previous measurements using a parallel cyclic light scattering sampling loop indicated that when the turbidity meter captures an increment... When the turbidity index jumps above the 5 NTU threshold, the suspended phase in the mother liquor is mostly composed of free, monodisperse, extremely small primary crystal nuclei. However, once the system continues to evolve, causing the turbidity index to surge past the upper limit of 15 NTU, the simultaneously extracted flow field sample exhibits a large number of micron-sized secondary flocs on the offline particle size analyzer due to chain-like multi-level hydrogen bond association. Based on this fact, the quantitative optical difference range of 5 NTU to 15 NTU was identified as the critical effective detection signal characterizing the system before the formation of a hard crystal contact network. This quantitative optical difference range is not only reflected as the absolute increment of turbidity in macroscopic system control, but also further transformed into the slope of the first derivative over time for collaborative verification within the intelligent closed-loop system. This is because relying solely on absolute numerical windows may be affected by occasional fluctuations in the liquid surface. Transient optical noise caused by high-concentration stirring can lead to false positive triggers. However, by introducing the differential slope of the turbidity time derivative, static measurement can be transformed into dynamic rate monitoring. When the absolute increment crosses the window of 5 NTU to 15 NTU, the corresponding first-order time derivative, i.e., the instantaneous differential slope, will inevitably fall smoothly within the theoretical empirical range of 1.5 NTU / s to 4.5 NTU / s. By establishing this deterministic mapping bridging rule from the physical dimension of absolute scattering intensity to the time differential rate control dimension, the control system can use the boundary convergence of the differential slope to back-confirm the authenticity of the absolute increment reading, ensuring that the triggering action is precisely locked within the millisecond-level safe kinetic time window before the nascent crystal nuclei have developed a hard crystal contact network. The pulsed chemical intervention step relies on a pre-calibrated fast-response feeding loop for execution, and the execution parameters are based on the aforementioned pulsed feeding flux intensity. Dynamically set limiting conditions, adjust the back pressure of the feeding pipeline or the stroke frequency of the metering pump to ensure that the injection flow rate of the modifier solution is in sync with the real-time total volume of the reaction system at the injection time. Linear coupling, with the injection action controlled by a solenoid valve or pneumatic actuator with a response time of less than 100 milliseconds, ensures that the entire dose of modifier enters the high-shear mixing zone at the end of the reactor's agitator blades in the form of a turbulent jet within 10 to 30 seconds. Before homogeneous diffusion, the modifier completes convective coating of the crystal nuclei surface. In terms of specific hardware configuration and fluid dynamics operation standards, the pulse feeding system is specially equipped with a scaling-type pressure nozzle as the end fluid guide. The nozzle's outlet axis intersects with the tangential streamline formed by the rotation of the reactor's bottom turbine blades at an optimal angle of 30 to 45 degrees. The high-shear mixing zone is strictly defined as the forced annular space between the outer edge of the bottom turbine blades and the smooth inner wall of the reactor. By pre-calibrating and adjusting the back pressure regulating valve at the front end of the feeding pipeline, the Reynolds number of the fluid ejected at high speed from the nozzle throat is forced to climb and remain above 10,000, fully developing the turbulent region. The enormous initial turbulent kinetic energy accumulated in this way ensures that the modifier jet stream can instantly pierce and penetrate the reactor. The main system has a thick macroscopic fluid boundary layer. Specifically, in terms of the engineering structure configuration of this component, the scaling pressure nozzle used in this invention has a continuous Venturi geometry profile. Its throat core diameter is designed to be 2.0 mm, the semi-cone angle of the contraction section at the feed end is set to 15 degrees, and the semi-cone angle of the diffusion section at the discharge end is set to 7 degrees. Through this specific tapering and expanding structure, the ultimate conversion of fluid pressure energy into kinetic energy is achieved. In operation with the pre-stabilized pressure circuit, the control system maintains the mechanical back pressure at the feed end in a steady-state pressure range of 0.65 MPa to 0.75 MPa by adjusting the back pressure stabilizing valve at the front end of the feed pipeline. Under the coupling effect of this determined geometric configuration and pressure model, the instantaneous jet velocity at the nozzle outlet is forcibly accelerated to 12 m / s to 15 m / s, thereby generating extremely high and dense local shear energy during macroscopic fluid mixing. This ensures that the modifier solution can overcome the boundary layer viscous resistance as soon as it exits the nozzle, and fully develops turbulent state with a Reynolds number exceeding 10,000 at the fluid dynamics level.

[0032] The experimental design included a multi-dimensional comparison scheme with a control group and the sample group of the present invention. Control group 1 simulated the traditional liquid-phase oxidation process, i.e., no online monitoring or modifier intervention was performed during the reaction, only routine centrifugation and washing after the reaction. Control group 2 simulated the existing improved process, i.e., in the initial stage of the reaction (turbidity...) Add an equal amount of sodium tartrate modifier directly, with all other conditions consistent with the present invention; the sample group of the present invention strictly implements a pulse feeding strategy based on turbidity threshold triggering, that is, when the online turbidity reading first jumps to Immediately trigger the pulse injection of sodium tartrate solution, controlling the injection time within 15 seconds. The molar ratio of modifier to antimony is set at 1:60. The key parameter, the timing of modifier injection, is based on the competitive relationship between nucleation kinetics and aggregation kinetics. If injection is too early, as in control group 2, the modifier is easily deactivated by high-concentration hydrogen peroxide oxidation, and at this time, a large number of crystal nuclei have not yet been generated, so the modifier cannot play a role in sealing the newly formed surface. If injection is too late, irreversible hydrogen bonds have already formed between the crystal nuclei, and the modifier can only be adsorbed on the surface of the aggregates. Only when the turbidity jumps to a certain level can the modifier be effectively injected. Only by injecting within a microsecond window—the period during which primary crystal nuclei are generated but before large-scale aggregation—can effective coating of individual crystal nuclei be achieved. Furthermore, the pulse feeding flux intensity... The design needs to ensure that the modifier rapidly reaches adsorption saturation at the micro-mixing scale. This invention sets... To meet this kinetic requirement; the determination of this lower threshold is derived from the test results of a large number of cross-batch diffusion kinetics comparative experiments; during the experimental calibration, it was observed that when the pipeline pressure was artificially adjusted so that the calculated pulse feed flux intensity parameter J was lower than the numerical limit of 0.05, the laser particle size span index of the final sampled macroscopic product deteriorated in a stepwise manner; because the mass transfer supply rate of local modifier molecules to the grain surface is reduced when the flux intensity is lower than this, it lags behind the collision frequency of the primary crystal nuclei caused by the high-frequency Brownian motion, resulting in a low concentration of local coordination reactants, which makes it impossible to instantly construct a structurally complete chemical isolation layer on all crystal faces within milliseconds. Only when the flux intensity J is greater than or equal to 0.05, a sufficient excess solute diffusion driving force can accumulate in the micro-mixing region, thereby blocking the secondary contact aggregation path induced by surface exposure. During the experiment, the turbidity change curve and pH fluctuation of the reaction system were recorded in real time through an online data acquisition system. After the reaction, the products of each group underwent the same solid-liquid separation and washing (until the conductivity of the filtrate was reduced to a certain value). The product undergoes a drying process, and the particle size distribution (D50 and span) is determined using a laser particle size analyzer. The iron impurity content is detected using an inductively coupled plasma mass spectrometer (ICP-MS), and the microstructure is observed using a scanning electron microscope (SEM).

[0033] Table 1: Comparison of Performance Indicators of Sodium Pyroantimonate Products in Each Test Sample Group

[0034]

[0035] Referring to Table 1, the data reveal the impact of process intervention on product performance; the product D50 of control group 1 was as high as 12.5. Furthermore, the distribution span was wide (2.85), and the iron content reached 185 ppm, confirming that hard agglomeration and impurity encapsulation cannot be avoided during natural growth. Although a modifier was introduced into control group 2, the D50 only decreased to 5.8 due to improper injection timing. The iron content was 112 ppm, indicating that the modifier failed to effectively block agglomeration and impurity removal. In contrast, the D50 of the product in the sample group of this invention was reduced to 1.8. The particle size distribution range narrowed to 0.85, and the iron content dropped significantly to 18 ppm. SEM observation further confirmed that the sample group of this invention exhibited uniform monodisperse spherical particles without obvious agglomeration. The above results confirm that the pulsed competitive coordination mechanism based on turbidity threshold can effectively regulate crystal growth. High-throughput pulse injection within a specific turbidity window ensures that the modifier accurately occupies the active sites on the surface of the new crystal nuclei, and blocks hydrogen bond agglomeration between crystal grains through steric hindrance effect, thus achieving monodisperse growth. At the same time, it competes for iron ions through liquid phase complexation mechanism to prevent them from entering the crystal lattice. The synergistic effect of this dual effect enables the final product to meet the requirements of high-end photovoltaic glass for clarifying agents in terms of dispersibility and purity.

[0036] Example 3: This example combines Figures 1 to 3 The synthesis process of a surface-modified anti-agglomeration sodium pyroantimonate is described, such as... Figure 1 As shown, a homogeneous sodium antimonite bottom solution was constructed, a step which involved 85% [the solution being prepared]. Up to 95 Dissolve Filtration and temperature control are performed until the transmittance is greater than 99% and the turbidity baseline is less than 1 NTU. This initiates the oxidation reaction by continuously adding hydrogen peroxide solution at a constant rate to induce crystal nucleation. During this process, real-time data feedback is provided via online optical turbidity monitoring with a frequency of at least 1 Hz and a wavelength of 850 nm to 880 nm. Once the turbidity is detected to be within the 5 NTU to 15 NTU kinetic window for crystal nucleation, pulsed chemical intervention is triggered. Multidentate hydroxycarboxylate is injected within 10 to 30 seconds, ensuring a flux intensity J ≥ 0.05. This initiates the steric hindrance-guided growth and impurity complexation stage, forming a chemically bonded steric hindrance layer to inhibit hydrogen bond aggregation and competitively bind Fe ions in the liquid phase to achieve impurity separation. Finally, centrifugation removes the mother liquor and 105 NTU. Up to 120 The sodium pyroantimonate solid was obtained by temperature-curing and drying to produce monodisperse spherical solids coated with an organic carbon layer, with a D50 of 1 μm to 3 μm and an iron content of less than 20 ppm. The thermodynamic basis driving the stable operation of this liquid-phase competitive complexation separation mechanism lies in the fact that, under the actual production operation temperature of 55°C to 65°C and a strong alkaline medium with a pH of 10 to 12, the natural logarithm of the complexation stability constant of the polydentate hydroxycarboxylate against free iron ions, calibrated using a conventional isothermal titration calorimeter, is consistently between 20 and 10. The high point range is 22; while under the same ionic strength and bed conditions, the natural logarithm of the intrinsic adsorption equilibrium constant of these trace free iron ions on the sodium pyroantimonate solid phase interface usually hovers between 5 and 7; relying on the huge difference advantage of up to fourteen to fifteen orders of magnitude between these two core thermodynamic constants, the reaction liquid phase naturally constructs an invisible impurity rejection potential trap barrier, so that the adsorption and retention force of the liquid phase substrate on iron impurities occupies an absolute dominant position, thereby enabling the physical logic chain of automatic removal of iron impurities to reach a stable closed loop.

[0037] like Figure 2 As shown in the chart, this graph compares product parameters under three different drying modes. The horizontal axis represents the three processing methods: one-time high temperature, programmed temperature rise, and low temperature long time. The vertical axis and legend correspond to the organic carbon layer content in %, represented by horizontal bar charts, and the specific surface area in units of [missing information]. The relationship between the retention rate of the organic ligand layer on the surface of sodium pyroantimonate solid and the specific surface area of ​​the powder is represented by a diagonal bar graph; for example, Figure 3As shown, the hardware implementation of this process is based on a closed-loop control system. The homogeneous precursor construction module is responsible for the pretreatment of antimony trioxide, the preparation of sodium hydroxide base solution, and the constant-flow supply of hydrogen peroxide. The homogeneous base solution is then transported to a multi-physics coupled reactor equipped with temperature control, stirring, and a crystallization field. The internal state of the reactor is monitored in real-time by a sensing unit, i.e., an online optical turbidity probe. The turbidity signal is transmitted to the intelligent decision-making center and processed by a kinetic window locking algorithm before being sent to the pulse execution unit, i.e., the high-pressure modifier injection valve, as a trigger command. The multi-physics coupled reactor is specifically configured with a porous annular distribution plate for precise adjustment of the local supersaturation gradient, a built-in spiral temperature control coil, and a macroscopic circulation system for simultaneous operation. The flow and the dual-layer cross-type combined impeller with high microscopic shear rate jointly construct a stable coupled physical space for the flow field and temperature field. The specific underlying processing logic of the dynamic window locking algorithm is as follows: The intelligent decision center continuously acquires the raw turbidity data returned by the probe at a sampling frequency of not less than 10 Hz. First, it performs median filtering with a fixed window width to remove discrete electrical signal pulse interference caused by transient bubbles or impurity clumps. Then, the algorithm continuously calculates the first derivative of the net turbidity increment time of the most recent three filtered sampling cycles. When the differential slope value approximately jumps from the zero baseline and first stably remains within the preset positive empirical slope threshold range of the corresponding 5 NTU to 15 NTU range for more than 2 seconds, the system increments this one-dimensional data. The long-term trend is accurately determined to be a critical state where a large number of primary crystal nuclei burst forth and the internal hydrogen bonds are not yet stable. Immediately, a high-level trigger command with no delay is transmitted to the subsequent stage. In the actual control software configuration, the preset positive empirical slope threshold range is specifically quantified and set to 1.5 NTU / s to 4.5 NTU / s. This specific value range is determined based on a 6-fold amplification of the standard deviation of the homogeneous bottom liquid background noise, combined with engineering corrections to the highest spontaneous turbidity fluctuation rate during the first 5 minutes of the oxidation reaction induction period. If it is below 1.5 NTU / s, the control algorithm determines that the current turbidity increase may only be due to local optical disturbances caused by the flow of tiny bubbles or the rotation of the agitator, thus automatically filtering out false positive signals. The risk of accidental triggering is high. If the rate is higher than 4.5 NTU / s, it indicates that the oxidation crystallization reaction is too violent and the reaction rate exceeds the limit of the local rapid diffusion coverage of the modifier. The system will immediately link the upstream hydrogen peroxide supply metering pump to perform a speed reduction operation. Only when the slope change rate is stably maintained in the range of 1.5 NTU / s to 4.5 NTU / s for more than 2 seconds can the system confirm that the system has truly entered the window period of large-scale primary crystal nuclei explosion. The execution unit then injects the material into the reactor in a pulse manner. After the reaction is completed, the slurry is output to the product post-processing module. After solid-liquid separation to remove impurities, deep washing, and programmed temperature rise drying, the final product is a surface-modified, anti-agglomeration, and high-purity sodium pyroantimonate.

[0038] Example 4: This example illustrates a standardized engineering calibration procedure for establishing the construction temperature and feed control parameters of the homogeneous sodium antimonylate substrate and oxidation reaction. This procedure aims to eliminate uncertainties in reaction kinetics and ensure that process parameters are set based on objective physicochemical response characteristics. For the precursor dissolution stage, a reaction calorimeter equipped with a precision heat flux sensor and an online conductivity meter was constructed. To determine the optimal dissolution temperature window for antimony trioxide in sodium hydroxide solution, a temperature gradient scan experiment was performed. The experimental temperature range was set as follows: to Step size is Monitoring data shows that when the system temperature is below At that time, the lattice dissociation barrier of antimony trioxide is relatively high, and the dissolution rate constant is low, resulting in the solution transmittance not reaching the target value within the preset reaction time. The remaining trace amounts of unreacted solid particles become heterogeneous nucleation centers in the subsequent crystallization process, disrupting the consistency of the product. When the system temperature exceeds 95°C... At this time, the solvent evaporation rate increases exponentially, leading to unsteady fluctuations in liquid volume and bottom liquid concentration, and increased energy consumption. to Within a given temperature range, the dissolution reaction reaches a thermodynamic and kinetic equilibrium, the solution transforms into an optically clear state within a specified time, and the component concentration remains constant. Based on this, to The standard process temperature for constructing a homogeneous bottom liquid is locked in.

[0039] For the oxidation crystallization stage, an online redox potential (ORP) monitoring system was introduced to quantitatively control the hydrogen peroxide feeding kinetics. Under constant stirring rate, the correlation between different hydrogen peroxide flow rates and the system's ORP value response and final crystal morphology was investigated. Experimental observations showed that when the flow rate was too high, the system's ORP reading instantaneously exceeded the limit. When the local hydrogen peroxide concentration is too high, a violent exothermic reaction is triggered, driving a sharp increase in supersaturation. This leads to the explosive and disordered formation of crystal nuclei and thermal agglomeration. Conversely, when the flow acceleration rate is too low, causing the ORP reading to remain below a certain level for an extended period... At that time, insufficient oxidation driving force limited crystal growth due to the surface reaction rate, leading to a decrease in production capacity. Through feedback regulation testing, a control strategy linking the hydrogen peroxide flow acceleration rate to the system's ORP value was determined. Adjusting the flow rate ensured a smooth increase and maintenance of the ORP value during the reaction process. to Within the steady-state range, the oxidation rate and crystal growth rate are matched within this potential window, and the product exhibits optimal monodispersity and lattice integrity.

[0040] Example 5: To address the impact of potential equipment differences and raw material batch fluctuations on process stability in industrial production, this example constructs a pre-deployment calibration procedure for on-site deployment. This aims to ensure the reproducibility and stability of the pulsed competitive coordination mechanism based on turbidity thresholds under different production scenarios. Baseline calibration of the online turbidity monitoring system is performed. After injecting deionized water into a clean reactor and starting the stirring at the set speed, the system temperature is adjusted to 60°C. Record the stable reading of the turbidimeter at this time as the background scattering baseline value. A gradient turbidity standard curve was constructed using a standard formalin suspension to calibrate the linear response coefficient of the sensor, ensuring that... to The measurement error within the key monitoring interval is less than This step eliminates the interference of sensor drift and background noise on the accuracy of determining the nucleus primordial dynamics window, and establishes a unified physical benchmark.

[0041] Secondly, a dynamic response test was performed on the pulse feeding system. In a non-reactive state, the output pressure and valve opening sequence of the automated feeding device were set. A precision mass flow meter was used to record the injection curve of the modifier solution in real time. By fine-tuning the control parameters, the deviation between the actual injection volume and the preset target value was controlled within a certain range. Within, and the injection action is strictly within Completed within a two-second window, this test verifies the pulse feeding throughput intensity. The controllability ensures that the modifier can cover the surface of the newly formed crystal nuclei at the expected instantaneous high concentration, thereby ensuring the effective establishment of the steric hindrance effect.

[0042] Example 6: Addressing the impact of different batches of antimony trioxide raw materials and fluctuations in production environment temperature and humidity on the grain size consistency of the final product, this example describes an offline generation and verification process for an adaptive parameter matrix. The aim is to provide a dynamic process parameter adjustment strategy based on raw material characteristic feedback for the production system. A correlation database between raw material properties and optimal process parameters is established. Five representative antimony trioxide raw materials from different sources are selected. Their initial average particle size is measured using a laser particle size analyzer, and their specific surface area is measured using a specific surface area analyzer. For each raw material, three different modifier injection timing thresholds are set in a laboratory-scale reactor. , , Two different feed flux intensities were used to conduct orthogonal experiments. The particle size distribution range and iron impurity content of sodium pyroantimonate products obtained from each group of experiments were recorded. The optimal combination of process parameters that achieves the best product performance was selected, and the raw material characteristic parameters and the corresponding optimal process parameters were entered into the database.

[0043] Secondly, the system performs pre-production adaptive adjustments based on this database. Before each batch of formal production, the system performs rapid physical property testing on the new batch of raw materials to obtain particle size and specific surface area data. Based on the test results, the control system retrieves the nearest raw material characteristic record in the database and automatically calls the corresponding optimal modifier injection turbidity threshold and feeding parameter settings. If the new raw material characteristics are within the interpolation range of existing records, the system uses a linear interpolation algorithm to generate recommended process parameters. Through this process, the system can perform feedforward compensation for the microscopic differences in raw materials, ensuring that the uniformity of grain size and purity of the final product are maintained within the set specifications under different raw material input conditions.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate, characterized in that, The process involves pulsed chemical intervention based on the nucleation kinetics window determined by online optical turbidity monitoring, and includes the following steps: Step S1: Construct a homogeneous sodium antimonylate bottom solution by dispersing antimony trioxide powder in an aqueous sodium hydroxide solution and carrying out a dissolution reaction at a temperature of 85°C to 95°C until the solution becomes a clear state with a transmittance of more than 99%. Filter to remove insoluble matter and keep the temperature of the filtrate constant at 55°C to 65°C to establish a homogeneous sodium antimonylate bottom solution with a turbidity baseline value of less than 1 NTU. Step S2, crystal nucleus capture and pulse modification: Hydrogen peroxide solution is added to the homogeneous sodium antimonite substrate at a constant flow rate to initiate an oxidative crystallization reaction. The real-time turbidity of the reaction system is monitored using an online turbidity sensor at a frequency of not less than 1 Hz. When the turbidity of the reaction system rises from the baseline value to the range of 5 NTU to 15 NTU for the first time, the modifier injection action is triggered. A multidentate hydroxycarboxylate solution is injected into the reaction system in one go within 10 to 30 seconds. The molar ratio of multidentate hydroxycarboxylate to antimony element is 1:100 to 1:

50. Step S3, steric hindrance-guided growth and separation: After the modifier injection is completed, the remaining hydrogen peroxide solution is added until the oxidation reaction endpoint is reached, and the reaction is maintained with stirring for 1.5 to 2.5 hours. The multidentate hydroxycarboxylate forms a chemically bonded steric layer on the surface of the new crystal nuclei and simultaneously complexes metal impurity ions in the liquid phase. After the reaction is completed, the resulting slurry is subjected to solid-liquid separation, the liquid phase containing the metal impurity complex is removed, the solid product is collected and washed with water and dried at 105 to 120 degrees Celsius to obtain sodium antimonate pyroantimonate solid.

2. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, The polydentate hydroxycarboxylate solution is selected from sodium tartrate aqueous solution or sodium citrate aqueous solution; in step S2, the mass percentage concentration of the polydentate hydroxycarboxylate solution is 15% to 25%, and the solution is preheated to the same temperature as the reaction system before injection; the modifier injection is performed by a high-pressure feeding device, which provides turbulent mixing energy to the reaction system within an injection time of 10 to 30 seconds, so that the polydentate hydroxycarboxylate completes coordination end-capping before the hydroxyl groups on the crystal nucleus surface undergo dehydration condensation reaction.

3. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, In step S1, the initial concentration of the sodium hydroxide aqueous solution is controlled at 3.5 mol / L to 4.5 mol / L, and the molar ratio of antimony trioxide to sodium hydroxide is 1:2.2 to 1:2.

5. The duration of the dissolution reaction is 30 minutes to 60 minutes, and after filtering to remove insoluble matter, the step further includes adding deionized water to the filtrate to adjust the antimony concentration to 0.8 mol / L to 1.2 mol / L.

4. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, In step S2, the modifier injection action satisfies the pulse feeding throughput intensity. The limiting conditions, among which, Defined as the ratio of the modifier injection rate to the total volume of the reaction system, and satisfying the following relationship: ,in, The amount of the injected polydentate hydroxycarboxylate, in moles; The total volume of the reaction system at the injection point is expressed in liters. The duration required to complete the injection, in seconds; pulse feed flux intensity. The limitation is used to ensure that the polydentate hydroxycarboxylate reaches the saturated adsorption concentration during the micro-mixing time before the Brownian motion collision of the crystal nucleus.

5. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, In step S2, the flow rate of the hydrogen peroxide solution is controlled such that the induction period for the turbidity of the reaction system to rise from 1 NTU to 5 NTU is controlled between 5 and 15 minutes; the online turbidity sensor uses the scattered light turbidity measurement method, with the measuring probe placed halfway below the surface of the reaction liquid, and the measurement wavelength selected in the near-infrared range of 850 nm to 880 nm.

6. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, In step S3, the stirring linear velocity of the stirring reaction is set to 2.0 m / s to 3.0 m / s. The steric hindrance directed growth process is carried out in an alkaline environment with a pH value of 10 to 12. Within this pH range, the complexation stability constant of the polydentate hydroxycarboxylate for iron ions is greater than the adsorption equilibrium constant on the surface of sodium pyroantimonate crystals, thereby driving iron ions to migrate from the solid-liquid interface to the liquid phase bulk.

7. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, Sodium pyroantimonate solid is a directly dried product without mechanical grinding or air jet milling; the average particle size D50 of sodium pyroantimonate solid is 1 micrometer to 3 micrometers, and under a scanning electron microscope, it appears as isotropic cubic or spherical monodisperse particles. The particle surface is coated with an organic carbon layer bonded by chemical bonding, and the content of the organic carbon layer is 0.2% to 0.5%.

8. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, In step S3, the solid-liquid separation operation adopts centrifugal separation, and the centrifugal separation factor is controlled between 800 and 1200; the water washing operation is performed until the conductivity of the washing filtrate drops to below 20 microsiemens per centimeter; the drying operation adopts a programmed temperature rise mode, drying at 60 degrees Celsius to 80 degrees Celsius for 30 minutes to remove free water, and then heating to 105 degrees Celsius to 120 degrees Celsius for 60 minutes to solidify the surface coordination layer.

9. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, Before constructing the homogeneous sodium antimonyate substrate in step S1, a pretreatment step for antimony trioxide raw material is also included, in which antimony trioxide powder is ultrasonically dispersed in anhydrous ethanol for 10 to 20 minutes, filtered and dried to remove gases and impurities physically adsorbed on the surface of the raw material.

10. The process for synthesizing surface-modified, anti-agglomeration sodium pyroantimonate according to claim 1, characterized in that, The process is used to prepare clarifying agents for ultra-white photovoltaic glass. The sodium pyroantimonate solid prepared by this process contains less than 20 parts per million of ferric oxide. Moreover, during the initial stage of glass melting at 600 to 800 degrees Celsius, the sodium pyroantimonate solid generates microbubble flow through the thermal decomposition of the surface organic ligand layer, which promotes the secondary dispersion of clarifying agent particles in the glass melt.

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