Low-adhesion anti-adsorption ash inclusion deoxidizer and preparation method thereof

Abstract

The invention relates to the technical field of food preservation, in particular to a low-adhesion anti-adsorption ash inclusion deoxidizer and a preparation method thereof. The method comprises the following steps: carrying out unique surface and structure modification on reduced iron powder serving as a main material of a deoxidizing agent: growing nanoscale iron oxide / hydroxide filaments on the surface of the iron powder in situ through controllable damp-heat oxidation, and constructing a micro-nano structure layer; a micron-sized lubricant (such as modified calcium stearate) is nanocrystallized and synchronously and mechanically embedded into the micro-nano structure layer under the shearing action of high-speed airflow by adopting an airflow crushing technology, so that core particles with iron as an inner core and a firmly combined lubricant-oxygen chemical fiber composite structure as a surface layer are formed; and finally, mixing with components such as iron sand and white carbon black. According to the invention, the traditional mode of physically mixing auxiliary materials is thoroughly changed, and the core particles of the deoxidizer are endowed with extremely low surface energy and permanent lubricating property through surface engineering and mechanochemical methods, so that the angle of repose of the core particles is reduced to 46 degrees or below, and meanwhile, the deoxidizing activity is completely maintained.

Description

Technical Field

[0001] This invention relates to the field of food preservation technology, specifically to a low-adhesion, anti-adsorption ash-laden deoxidizer and its preparation method. Background Technology

[0002] Oxygen absorbers are key materials for the preservation and protection of products such as food, pharmaceuticals, and precision instruments. Their core function is to effectively reduce oxygen concentration through a chemical reaction with oxygen in the packaging environment, thereby inhibiting microbial growth, preventing oil oxidation and metal corrosion, and significantly extending the product's shelf life and storage stability. Currently, the mainstream oxygen absorber system on the market is the iron-based oxygen absorber, which is widely used due to its high oxygen absorption capacity, low cost, and high safety. This type of oxygen absorber is typically composed of reduced iron powder as the main reactant, along with various auxiliary materials such as sodium chloride, activated carbon, diatomaceous earth, talc, and stearates added to regulate the reaction rate and improve processing performance. It is then encapsulated in non-woven fabric, composite paper, or plastic film packaging materials with high oxygen permeability and suitable strength. The technological development of the entire industry has consistently revolved around the core challenge of improving its processability and reliability while ensuring and even enhancing its core oxygen absorption performance.

[0003] Although iron-based deoxidizer technology is relatively mature, some persistent technical challenges remain in its production and application, severely hindering further improvements in production efficiency and product quality. The primary issue is the adhesion of the powder material. Due to the rough surface of reduced iron powder particles and the presence of hygroscopic components (such as salt) in the formulation, these fine powders easily adhere to the inner walls and surfaces of the feeding pipes, metering devices, and heat-sealing molds during high-speed feeding in automated packaging machines. This not only leads to inaccurate filling amounts in individual bags, affecting product consistency, but also necessitates frequent machine shutdowns for manual cleaning after short periods of operation. Otherwise, residual material will contaminate the heat-sealing area, causing incomplete sealing and product failure. Secondly, the adsorption problem caused by static electricity and capillary action is equally prominent. The deoxidizer packaging material (such as PE / paper / PTFE composite materials) easily generates and accumulates static charges during friction with the powder. These static forces attract fine iron powder to the microporous structure inside the packaging material. On the production line, this manifests as uneven material feeding, and on the final product, it manifests as dirt on the inside of the heat-sealed area. This dirt easily transforms into rust spots under the high-temperature and high-humidity conditions of storage and transportation, severely affecting the product's appearance and causing negative consumer concerns about product quality. Furthermore, existing solutions to address these problems, such as adding more types of lubricants (iron sand, calcium stearate, talc, silica, etc.) or adjusting moisture content and particle size, often have limited effectiveness or introduce new side effects, resulting in a piecemeal approach.

[0004] Faced with the aforementioned common challenges in the industry, existing technologies have disclosed numerous tentative solutions. For example, invention CN116098257A discloses a deoxidizer and its production process, which focuses on regulating the internal moisture migration of the system by adding water-absorbing resins or specific salts, aiming to alleviate the agglomeration and adhesion phenomena exacerbated by moisture absorption. However, this method often causes unpredictable interference with the deoxidation reaction rate itself, and may even sacrifice oxygen absorption efficiency. Most of these existing improvement solutions follow the idea of ​​simply physically mixing multiple functional additives in the formulation, failing to fundamentally change the physicochemical properties of the iron powder particle surface. There is a lack of synergistic effect between the components, and the improvement effect has bottlenecks and is difficult to sustain. Therefore, there is an urgent need in this field for an innovative technical path that can start from the source of material surface modification and structural design to develop a new deoxidizer product and its preparation method that has extremely low adhesion, excellent antistatic adsorption capacity, high environmental stability, and does not compromise its core deoxidation activity.

[0005] Existing technologies all focus on improving the performance of deoxidizers by externally adding various functional powders, but have consistently failed to break free from the mindset of "physical mixing." This method cannot solve the fundamental problems of weak bonding between additives and iron powder, easy migration, and easy failure under long-term storage or harsh environments. Therefore, developing a new method and product that can achieve long-lasting, stable anti-adhesion based on the surface properties of iron powder itself has become the key to breaking through the technological bottleneck in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a deoxidizer with low adhesion and anti-adsorption of ash inclusions and its preparation method. This invention completely changes the traditional physical mixing mode of auxiliary materials. Through surface engineering and mechanochemical methods, the core particles of the deoxidizer are endowed with extremely low surface energy and permanent lubrication properties, reducing its angle of repose to below 46°, while fully maintaining its deoxidizing activity.

[0007] A low-adhesion, anti-adsorption, and ash-retaining deoxidizer, wherein the core of the deoxidizer is reduced iron powder particles, and a micro-nano composite structure layer is in situ constructed on the surface of the reduced iron powder particles; the micro-nano composite structure layer is composed of nano-sized iron oxide / hydroxide filaments generated by partial oxidation of the iron powder surface and micron-sized lubricant particles uniformly embedded therein.

[0008] Preferably, the overall angle of repose of the deoxidizer is not greater than 46 degrees.

[0009] Preferably, the modified calcium stearate is calcium stearate coated with a nanoporous silica layer, the thickness of which is 10-50 nm and the pore size is 2-10 nm, and the nanoporous silica coating layer accounts for 5-15% of the total mass of the modified calcium stearate particles.

[0010] The present invention also discloses a method for preparing calcium stearate coated with a nanoporous silica layer as follows: micron-sized calcium stearate particles are dispersed in an ethanol-water mixed solvent, a silicon source and an alkaline catalyst are added, and a sol-gel reaction is carried out at 40-60°C. After centrifugation and drying, the product is obtained. The silicon source includes, but is not limited to, tetraethyl orthosilicate; the catalyst includes, but is not limited to, ammonia.

[0011] Preferably, the modified talc is an organic-inorganic hybrid modified talc.

[0012] Preferably, the method for preparing the organic-inorganic hybrid modified talc is as follows: talc is dispersed in an aqueous ethanol solution, siloxane coupling agent KH-560 and propyl gallate are added, the mixture is reacted at 60-70°C for 2-4 hours, and the modified talc is obtained after filtration, washing and drying.

[0013] Preferably, the micron-sized lubricant is self-modified calcium stearate, magnesium stearate, and modified talc, with a particle size distribution between 100 nanometers and 5 micrometers, and contents of 0.5-4%, 0.5-4%, and 1-3%, respectively. The percentages mentioned above are the percentages of the mass of each substance relative to the total mass of the low-adhesion, anti-adsorption, and ash-containing deoxidizer prepared by the present invention.

[0014] Preferably, the particle size distribution of the reduced iron powder particles satisfies the following: particles larger than 80 mesh account for 12.28-22.30%, and particles smaller than 300 mesh account for 1.00-2.29%.

[0015] This invention also discloses a method for preparing a low-adhesion, anti-adsorption ash-filled deoxidizer, comprising the following steps: S1. Controllable surface oxidation: Place 40-50% reduced iron powder in a reaction environment with a temperature of 60-85℃ and a relative humidity of 90-98% for 10-30 minutes to grow nano-sized iron oxide / hydroxide filaments in situ on its surface. S2. Lubricant Nano-Sizing and Embedding: Reduced iron powder with nano-sized iron oxide / hydroxide filaments grown in situ on the surface obtained in step S1 is fed together with micron-sized lubricant particles into an air jet mill. Under the shearing action of high-speed airflow, the micron-sized lubricant particles are pulverized and embedded into the micro-nano composite structure layer on the surface of the iron powder by mechanical force, forming firmly bonded composite particles. S3. Mixing and Stabilization: The composite particles obtained in step S2 are mixed with 5-10% iron sand, 12-16% silica, 0.5-3% starch, and other auxiliary materials to obtain the final internal material.

[0016] Preferably, the reaction environment in step S1 is provided by a controllable humid heat chamber, and the processing time is 15 minutes.

[0017] Preferably, the pressure of the air jet mill in step S2 is 0.8-1.2 MPa.

[0018] Preferably, the mixing in step S3 is carried out in a three-dimensional mixer for 20-40 minutes.

[0019] The other auxiliary materials are activated carbon, diatomaceous earth, and sodium chloride, with a mass ratio of 1:(4-5):1.

[0020] The deoxidizer prepared by this invention does not clump after being placed at 25°C and 85%RH for 8 hours, and the inner wall of the packaging is free of black spots or rust after long-term storage.

[0021] The low-adhesion, anti-adsorption, and ash-retaining deoxidizer prepared by this invention has a powder residue area accounting for ≤10% of the heat-sealing area.

[0022] A system for preparing a low-adhesion, anti-adsorption, ash-laden deoxidizer according to the present invention comprises, in sequence: a controllable humid heat reaction chamber for surface oxidation of iron powder; an airflow pulverizing and surface embedding device for nano-sizing and embedding a lubricant into the surface of the oxidized iron powder; and a three-dimensional mixer for mixing the composite particles with other components.

[0023] The core innovation of this invention: The core innovation of this invention lies in taking a different approach and creating a set of deoxidizer anti-adhesion modification technology system "from the inside out". The key lies in "in-situ surface construction" and "mechanical embedding", rather than "physical mixing".

[0024] 1. Methodological Innovation – From “Mixing” to “Construction”: This invention, for the first time, abandons the traditional method of simply mixing lubricant anti-adhesion components into deoxidizers, and creatively proposes a two-step method of “in-situ growth followed by mechanical embedding.” The first step, controlled hydrothermal oxidation: By precisely controlling temperature and humidity, a spontaneous reaction is stimulated on the surface of iron powder, causing it to “grow” a layer of interwoven nano-oxidation filaments. This filament layer is chemically integrated with the iron powder matrix, possessing extremely high stability, and its rough nanostructure itself reduces contact area and adhesion. The second step, airflow pulverization embedding: This is not a simple pulverization and mixing process. We co-particle the micron-sized lubricant with the treated iron powder using airflow pulverization. Under the intense shearing and particle collision effects of high-pressure airflow (0.8-1.2 MPa), two objectives are simultaneously achieved: a) breaking the micron-sized lubricant into nanoparticles; b) using extremely high mechanical force to “ram” or “weld” these newly formed nano-lubricant particles with extremely high surface energy into the nanofiber network formed in the first step. This process forms a composite core-shell structure integrating iron powder, oxide filaments, and nano-lubricant.

[0025] 2. Structural Innovation – Forming an “Anchored” Composite Core-Shell Structure: The resulting core particle has each lubricant nanoparticle on its surface tightly held by surrounding oxide filaments like “arms” (mechanical interlocking), rather than physical adsorption. This structure solves the century-old problem of lubricant detachment and migration in traditional methods, providing a permanent lubrication effect. Its effect of reducing surface energy and coefficient of friction is fundamental and lasting.

[0026] 3. Innovative Results – A Leap in Performance: By fundamentally altering the physicochemical properties of the iron powder surface, this solution far exceeds expectations. The resulting deoxidizer exhibits an extremely low angle of repose (≤46°) and excellent flowability. In production, the residual powder area drops dramatically from the traditional 90% to below 10%, achieving near-zero adhesion. In high-humidity environments, its hydrophobic surface and anchored lubricant significantly enhance its anti-caking ability. All these performance improvements remain unaffected by its core deoxidizing capacity.

[0027] 4. Structural Innovation – Pioneering a New “Dual-Effect Composite Lubrication” System: This invention abandons the traditional approach of simply mixing lubricants physically, and innovatively performs deep synergistic modification of two key lubricants at the molecular and structural levels. First, a layer of nanoporous silica is in situ coated onto the surface of calcium stearate particles using the sol-gel method, constructing a “calcium stearate@SiO2” core-shell structure. This structure not only greatly enhances the mechanical strength of the lubricant particles using the three-dimensional network framework of the SiO2 layer, but its abundant silanol groups can also form strong chemical adsorption and hydrogen bonding with the oxide filaments on the iron powder surface, achieving dual fixation of “mechanical intercalation” and “chemical anchoring,” completely solving the problem of lubricant migration and shedding. Second, talc powder is modified using organic-inorganic hybrid technology. After hydrolysis, the siloxane coupling agent (KH-560) combines with the hydroxyl groups on the talc powder surface, while the other end bonds with the phenolic hydroxyl groups of propyl gallate, successfully grafting organic antioxidant molecules onto the inorganic talc powder surface via covalent bonds. This not only significantly improves the compatibility and dispersibility of talc with organic systems, but also endows it with synergistic antioxidant properties, effectively scavenging free radicals in the environment and delaying the inactive oxidation of iron powder, thus enhancing the product's environmental stability from another perspective. The synergistic effect of these two modified lubricants constitutes a new system that combines ultimate lubrication, strong anchoring, and enhanced functionality.

[0028] The beneficial technical effects of this invention: The deoxidizer provided by this invention achieves outstanding comprehensive technical effects through a unique "controlled oxidation-mechanical embedding" preparation method. Its internal material exhibits excellent flowability, the angle of repose is significantly reduced to an excellent level, achieving near-zero adhesion in production equipment. The powder residue area in the heat-sealing zone is controlled within an extremely low range, and the equipment can operate continuously for more than eight hours without cleaning. The amount of residue at the discharge port is reduced to a negligible level. This product exhibits extraordinary stability in harsh environments with high temperature and humidity, showing no clumping or agglomeration even after prolonged storage. More importantly, these performance improvements do not sacrifice its core function; the deoxidizer maintains extremely high oxygen uptake capacity and reaction efficiency. After long-term storage, the inner wall of the finished product packaging remains clean and new, completely eliminating the problems of black spots and rust caused by electrostatic adsorption and capillary action. This invention fundamentally solves the inherent problems of traditional deoxidizers in terms of flowability, adhesion, environmental stability, and long-term storage reliability, significantly improving production efficiency and product quality. Attached Figure Description

[0029] Figure 1 This is a process flow diagram for preparing a low-adhesion anti-adsorption deoxidizer according to an embodiment of the present invention.

[0030] Figure 2 The diagram shows the flowability test results of iron powder with different particle sizes according to the present invention (free flow: the material can flow directly down in the hole; stirring is required for flow by human intervention).

[0031] Figure 3 The diagram shows the antistatic powder inclusion phenomenon of different inner materials of the present invention (left: original inner material, the residual powder area accounts for 90% of the heat-sealed area; right: improved inner material, the residual powder area accounts for ≤10% of the heat-sealed area).

[0032] Figure 4 This is a diagram showing the clumping and agglomeration of the original formula of this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0034] Example 1 Raw material pretreatment: Weigh 100 kg of reduced iron powder. The particle size distribution, as determined by testing, is as follows: 80 mesh and above 15.5%, 100 mesh 13.8%, 160 mesh 28.2%, 200 mesh 29.5%, 300 mesh 11.0%, and below 300 mesh 2.0%. Spread the powder evenly in a material tray, with a thickness not exceeding 2 cm. Step S1. Controlled Surface Oxidation: Place the material tray in a controlled humid heat reaction chamber, set the chamber temperature to 80℃ and the relative humidity to 95%. The treatment time is 15 minutes. After treatment, the surface color of the iron powder is slightly darker, and uniformly distributed nano-scale filamentous oxidation products can be observed under an electron microscope. Step S2. Lubricant nano-sizing and embedding: The treated iron powder, along with 6.7 kg of micron-sized modified calcium stearate, 5.6 kg of micron-sized magnesium stearate, and 4.5 kg of modified micron-sized talc powder, are fed into an air jet mill. The working pressure of the air jet mill is set to 1.0 MPa, and the feeding speed is 25 kg / h. The treated material is collected by a cyclone separator. Step S3. Mixing and Stabilization: All the composite particles obtained in S2, along with 17.8 kg of iron sand (80-100 mesh), 31.1 kg of silica (hydrophilic, specific surface area 200 m² / g), 5.6 kg of edible corn starch, and 51.1 kg of other auxiliary materials (activated carbon, diatomaceous earth, and sodium chloride in a mass ratio of 1:4:1), are added to a three-dimensional mixer. The mixer speed is set to 15 rpm and the mixing time is 20 minutes. After uniform mixing, the mixture is discharged to obtain the final product.

[0035] The modified calcium stearate has a nanoporous silica coating layer with a thickness of 30 nm and a pore size of 5 nm, and the nanoporous silica coating layer accounts for 10% of the total mass of the modified calcium stearate particles.

[0036] The modified calcium stearate was prepared as follows: 100 g of micron-sized calcium stearate particles were weighed and dispersed in 1500 mL of an ethanol-water mixed solvent (ethanol to water volume ratio of 4:1). The dispersion was carried out at 40 °C and 300 rpm for 30 minutes. Subsequently, 30 mL of ammonia water (25% concentration) and 15 g of tetraethyl orthosilicate (TEOS) were added to the system. The temperature was raised to 60 °C and the stirring rate was adjusted to 400 rpm. The reaction was carried out under reflux for 4 hours. After the reaction, the mixture was cooled to room temperature and centrifuged at 10,000 rpm for 8 minutes to collect the solid product. The solid product was washed three times with anhydrous ethanol. Finally, the obtained solid was dried in a vacuum drying oven at 70 °C for 6 hours to obtain calcium stearate composite particles with a nanoporous silica layer on the surface. Characterization showed that the silica coating thickness of the composite particles was approximately 30 nm, the pore size distribution was 8 nm, and the mass percentage of the coating layer was approximately 10%.

[0037] The modified talc powder was prepared as follows: 100 g of talc powder was weighed and dispersed in 1000 mL of 75% ethanol aqueous solution, and dispersed for 30 minutes at 65°C and 400 rpm to form a uniform suspension; then 2.5 g of siloxane coupling agent KH-560 and 1.0 g of propyl gallate were added to the system, and the temperature was maintained at 65°C and the reaction was carried out at the same stirring rate for 3 hours; after the reaction was completed, the mixture was cooled to room temperature, and the solid product was collected by vacuum filtration and washed three times with 75% ethanol aqueous solution to remove unreacted modifier; finally, the filter cake was placed in a vacuum drying oven at 75°C and dried for 8 hours to obtain organic-inorganic hybrid modified talc powder. Characterization showed that organic functional groups were successfully grafted onto the surface of the modified talc powder, the hydrophobicity and antioxidant properties were significantly improved, and the compatibility with the polymer matrix was significantly improved.

[0038] Example 2 Raw material pretreatment: Same as in Example 1; Step S1. Controlled surface oxidation: Adjust the wet heat treatment conditions to a temperature of 70℃, a relative humidity of 98%, and a treatment time of 20 minutes; Step S2. Lubricant Nano-Sizing and Embedding: The working pressure of the air jet mill is adjusted to 0.9 MPa. The lubricant formulation is the same as in Example 1; Step S3. Mixing and stabilization: exactly the same as in Example 1.

[0039] Example 3 Raw material pretreatment: Same as in Example 1; Step S1. Controlled surface oxidation: Same as in Example 1; Step S2. Lubricant nano-sizing and embedding: The working pressure of the air jet mill is 1.0 MPa, and the lubricant formula is adjusted to: 5.2 kg modified calcium stearate, 5.6 kg magnesium stearate, and 6.0 kg modified talc. Step S3. Mixing and stabilization: exactly the same as in Example 1.

[0040] Comparative Example 1 (Traditional Physical Hybrid Scheme) Raw materials: Weigh 100 kg of reduced iron powder identical to that in Example 1, without any pretreatment; Mixing process: The reduced iron powder, along with 6.7 kg of micron-sized modified calcium stearate, 5.6 kg of micron-sized magnesium stearate, 4.5 kg of micron-sized modified talc, 17.8 kg of iron sand, 31.1 kg of silica, 5.6 kg of edible corn starch, and 51.1 kg of other auxiliary materials, are all added into a three-dimensional mixer at one time. Mixing parameters: Set the mixer speed to 15 rpm and the mixing time to 20 minutes (consistent with step S3 in Example 1). Discharge the mixture after it is thoroughly mixed.

[0041] Objective: To simulate the physical hybrid scheme that is closest to existing technologies, serving as a benchmark for effect comparison.

[0042] Comparative Example 2 (only subjected to damp heat treatment, without mechanical embedding) Raw material pretreatment: Same as in Example 1, the iron powder was subjected to wet heat treatment (80℃, 95%RH, 15min). Subsequent process: The treated iron powder is directly added to a three-dimensional mixer along with all the auxiliary materials and mixed for 20 minutes; Objective: To investigate the contribution of the "in-situ surface oxidation" step alone, and to demonstrate that without the "mechanical embedding" step, the lubricant cannot be fixed and its effect is limited.

[0043] Comparative Example 3 (only air jet milling was performed, without the in-situ oxide layer) Raw materials: 100 kg of raw reduced iron powder that has not undergone wet heat treatment; Process: The iron powder, along with micron-sized lubricant (6.7 kg modified calcium stearate, 5.6 kg magnesium stearate, and 4.5 kg modified talc), is fed into an air jet mill and processed under a pressure of 1.0 MPa. Subsequently, it is mixed with iron sand, silica, starch, and other auxiliary materials in a three-dimensional mixer for 20 minutes. Objective: To examine the contribution of the "air jet milling" step alone and demonstrate that the lubricant embedding effect would be greatly reduced without a pre-formed "micro-nano oxide layer" as an anchoring substrate.

[0044] Comparative Example 4 (unmodified calcium stearate, unmodified talc) The rest is the same as in Example 1, except that calcium stearate and talc are unmodified.

[0045] Performance testing The testing standards are as follows: 1. Angle of repose: Determined according to the method specified in Clause 4.5 of GB / T 16913-2008 "Test Methods for Physical Properties of Dust".

[0046] 2. Oxygen uptake: The oxygen uptake and total oxygen uptake of a 2g sample over 24 hours were determined according to the method specified in Clause 5.3 of GB / T 41896-2022 "Quality Requirements for Deoxidizers for Food Use" at 25℃ and 60%RH.

[0047] 3. Percentage of residual powder area: After running in a simulated production environment for 30 minutes, the percentage of the area contaminated with powder in the heat-sealed area is calculated.

[0048] 4. Clumping Judgment: After being placed in an environment of 25℃ and 85%RH for 8 hours, the material is passed through a 3mm standard sieve. If there are residual clumps on the sieve, it is considered clumping.

[0049] 5. Black spot area: After the finished product has been stored for 6 months, observe and calculate the percentage of the area with black spots on the inner wall of the packaging bag.

[0050] 6. Cleaning time: The interval between continuous operation of the production equipment until the machine needs to be stopped for cleaning due to uneven feeding or excessive weight error caused by adhesion.

[0051] 7.30min residue: After the equipment has been running for 30 minutes, collect and weigh the total weight of the powder adhering to the feed port and surrounding area.

[0052] Test results: The test results of the examples and comparative examples are summarized in the table below.

[0053] Table 1: Comparison of Performance Test Results

[0054] Based on Table 1 above, the possible reasons for the differences in test results among Examples 1-3 can be analyzed: Examples 1-3 all employ the core process of this invention, and their performance is far superior to the comparative examples. The minor differences between them mainly stem from fine-tuning of process parameters. The conditions of Example 1 (80℃, 95%RH, 1.0MPa) are likely most favorable for forming an ideal, uniform, and robust micro-nano composite structure layer. The oxidation environment and slightly weaker pulverizing force of Example 2 (70℃, 98%RH, 0.9MPa) may result in slightly insufficient nanofiber density or lubricant embedding firmness, thus leading to slightly inferior flowability (angle of repose) and anti-adhesion (residue) indicators compared to Example 1. Example 3 changed the lubricant ratio; the higher proportion of talc may have slightly affected the overall surface lubrication uniformity, resulting in minor fluctuations in performance. These differences demonstrate the importance of precise optimization of process parameters for achieving optimal results.

[0055] Analysis of the possible reasons for the differences in test results between Examples 1-3 and Comparative Examples 1-4: The performance gap between the examples and the comparative examples stems from fundamental differences in technical principles. The lubricant in Comparative Example 1 (traditional mixing) is only physically adsorbed onto the surface of the iron powder, resulting in weak adhesion. Under friction and vibration, it easily migrates or detaches, quickly failing and thus exhibiting the worst performance. Although Comparative Example 2 (oxidation only) constructed a nanostructure and increased the specific surface area, it lacked the crucial low-surface-energy lubricating component. Relying solely on changes in physical morphology limited its anti-adhesion effect, and the high surface energy might actually exacerbate adsorption, making its performance far inferior to the examples. The mechanical force in Comparative Example 3 (pulverization only) could reduce the lubricant particle size and partially adhere, but lacking the nanoscale "anchors" and three-dimensional network provided by the in-situ oxide layer, the adhesion was weak, easily detaching during subsequent processing, significantly reducing its effectiveness. The key to the success of the embodiment lies in the synergistic effect of "in-situ oxidation" and "mechanical embedding": the nanofibers generated by oxidation provide a huge specific surface area and a complex network structure, providing excellent "anchoring" sites for the lubricant; high-pressure airflow pulverization provides huge mechanical force, nano-sized the lubricant and "embedded" it into this network, forming a strong, "reinforced concrete"-like composite structure. This structure makes the low surface energy properties durable and effective, thus achieving fundamental anti-adhesion. The fundamental reason for the performance failure of Comparative Example 4 is the lack of a strong "anchoring" mechanism. Unmodified calcium stearate only has weak physical adsorption with the iron powder surface and is very easy to migrate and fall off under friction and vibration; unmodified talc powder is only a simple physical isolation and is also easy to separate. Moreover, due to its hydrophilicity, it will become an "accomplice" in agglomeration in high humidity environments. However, this invention, through the SiO2 coating layer and organic-inorganic hybridization, creates strong mechanical interlocking and chemical bonding between the two lubricants and the oxidized fibers on the iron powder surface, "welding" them to the preset position, thereby achieving the durability and stability of the effect.

[0056] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A deoxidizer with low adhesion and resistance to adsorption of ash inclusions, characterized in that: The core of the deoxidizer is reduced iron powder particles, and a micro-nano composite structure layer is constructed in situ on the surface of the reduced iron powder particles; the micro-nano composite structure layer is composed of nano-sized iron oxide / hydroxide filaments generated by partial oxidation of the iron powder surface and micron-sized lubricant particles uniformly embedded therein.

2. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 1, characterized in that: The overall angle of repose of the deoxidizer is no greater than 46 degrees.

3. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 1, characterized in that, The micron-sized lubricant particles are modified calcium stearate, magnesium stearate, and modified talc, with particle sizes ranging from 100 nanometers to 5 micrometers, and contents of 0.5-4%, 0.5-4%, and 1-3%, respectively. The percentages are the percentages of the mass of each substance relative to the total mass of the low-adhesion, anti-adsorption, and ash-laden deoxidizer prepared by this invention.

4. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 3, characterized in that: The modified calcium stearate is calcium stearate coated with a nanoporous silica layer, the thickness of which is 10-50 nm and the pore size is 2-10 nm, and the nanoporous silica coating layer accounts for 5-15% of the total mass of the modified calcium stearate particles.

5. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 4, characterized in that, The method for preparing calcium stearate coated with a nanoporous silica layer is as follows: micron-sized calcium stearate particles are dispersed in an ethanol-water mixed solvent with a solid-liquid ratio of 1g:(10-20)mL. A silicon source and an alkaline catalyst are added, and a sol-gel reaction is carried out at 40-60℃. After centrifugation and drying, the product is obtained. The volume ratio of ethanol to water in the ethanol-water mixed solvent is 4:1-7:

3. The silicon source includes, but is not limited to, tetraethyl orthosilicate, with a mass ratio of (0.05-0.15):1 to calcium stearate. The catalyst includes, but is not limited to, ammonia water with a concentration of 25-28%, and the amount added is 1-3% of the volume of the ethanol-water mixed solvent. The centrifugation speed is 8000-12000rpm, and the time is 5-10 minutes. The drying conditions are vacuum drying at 60-80℃ for 4-8 hours.

6. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 3, characterized in that: The modified talc is an organic-inorganic hybrid modified talc.

7. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 6, characterized in that, The method for preparing the organic-inorganic hybrid modified talc is as follows: talc is dispersed in an ethanol aqueous solution, a siloxane coupling agent KH-560 and propyl gallate are added, and the mixture is reacted at 60-70℃ for 2-4 hours. After filtration, washing, and drying, the modified talc is obtained. The volume fraction of the ethanol aqueous solution is 60-80%. The solid-liquid ratio of the talc to the ethanol aqueous solution is 1g:(8-15)mL. The amount of siloxane coupling agent KH-560 added is 1.5-3.5% of the mass of the talc. The amount of propyl gallate added is 0.5-2% of the mass of the talc. The drying conditions are vacuum drying at 70-85℃ for 6-10 hours.

8. The low-adhesion, anti-adsorption ash-retaining deoxidizer according to claim 1, characterized in that, The particle size distribution of the reduced iron powder particles meets the following requirements: particles larger than 80 mesh account for 12.28-22.30%, and particles smaller than 300 mesh account for 1.00-2.29%.

9. A method for preparing a low-adhesion, anti-adsorption ash-containing deoxidizer as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Controllable surface oxidation: Place 40-50% reduced iron powder in a reaction environment with a temperature of 60-85℃ and a relative humidity of 90-98% for 10-30 minutes to grow nano-sized iron oxide / hydroxide filaments in situ on its surface. S2. Lubricant Nano-Sizing and Embedding: Reduced iron powder with nano-sized iron oxide / hydroxide filaments grown in situ on the surface obtained in step S1 is fed together with micron-sized lubricant particles into an air jet mill. Under the shearing action of high-speed airflow, the micron-sized lubricant particles are pulverized and embedded into the micro-nano composite structure layer on the surface of the iron powder by mechanical force, forming firmly bonded composite particles. S3. Mixing and Stabilization: The composite particles obtained in step S2 are mixed with 5-10% iron sand, 12-16% silica, 0.5-3% starch, and other auxiliary materials to obtain the final internal material. The other auxiliary materials are activated carbon, diatomaceous earth, and sodium chloride, with a mass ratio of 1:(4-5):

1. The reaction environment in step S1 is provided by a controllable humid heat chamber, and the processing time is 15 minutes; the pressure of the air jet mill in step S2 is 0.8-1.2 MPa; the mixing in step S3 is carried out in a three-dimensional mixer, and the mixing time is 20-40 minutes. The percentages mentioned above refer to the percentage of the mass of each substance relative to the total mass of the low-adhesion, anti-adsorption ash-containing deoxidizer prepared according to this invention.

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