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The surface modification of powders is largely achieved through the action of surface modifiers on the powder surface. Therefore, the formulation of surface modifiers (variety, dosage and usage) has an important influence on the modification effect of the powder surface and the application performance of the modified product.   The formulation of surface modifiers is highly targeted, that is, it has the characteristics of "one key opens one lock", which mainly includes the selection of varieties, determination of dosage and usage. 1. Screening of surface modifiers   The main considerations for selecting surface modifier varieties are the properties of powder raw materials, the purpose or application field of the product, and factors such as process, price and environmental protection.   (1) Properties of powder raw materials   The properties of powder raw materials are mainly acidity, alkalinity, surface structure and functional groups, adsorption and chemical reaction characteristics, etc. Surface modifiers that can react chemically or chemically adsorb with the surface of powder particles should be selected as much as possible, because physical adsorption is easy to desorb under strong stirring or extrusion during subsequent application. For example, the surfaces of acidic silicate minerals such as quartz, feldspar, mica, and kaolin can bond with silane coupling agents to form a relatively strong chemical adsorption; however, silane coupling agents generally cannot chemically react or chemically adsorb with carbonate alkaline minerals, while titanate and aluminate coupling agents can chemically adsorb with carbonate alkaline minerals under certain conditions and to a certain extent. Therefore, silane coupling agents are generally not suitable for use as surface modifiers for carbonate alkaline mineral powders, such as light calcium carbonate and heavy calcium carbonate.   (2) Product use   The use of the product is the most important consideration in selecting a surface modifier. Different application fields have different technical requirements for the application performance of powders, such as surface wettability, dispersibility, pH value, hiding power, weather resistance, gloss, antibacterial properties, UV protection, etc. This is one of the reasons why surface modifiers should be selected according to their use. For example, inorganic powders (fillers or pigments) used in various plastics, rubbers, adhesives, oily or solvent-based coatings require good surface lipophilicity, that is, good affinity or compatibility with organic polymer base materials, which requires the selection of surface modifiers that can make the inorganic powder surface hydrophobic and oleophilic; inorganic pigments used in ceramic blanks are not only required to have good dispersibility in the dry state, but also require good affinity with inorganic blanks and be able to be evenly dispersed in the blanks; surface modifiers for inorganic powders (fillers or pigments) used in water-based paints or coatings require good dispersibility, sedimentation stability and compatibility of the modified powders in the water phase. The selection of inorganic surface modifiers is mainly based on the functional requirements of the powder material in the application field. For example, to make titanium dioxide have good weather resistance and chemical stability, SiO2 and Al2O3 should be used for surface coating (film), and to make white mica pigments have good pearlescent effect, TiO2 should be used for surface coating (film). At the same time, different application systems have different components. When selecting a surface modifier, the compatibility and compatibility with the components of the application system must also be considered to avoid the failure of other components in the system due to the surface modifier.   (3) Modification process   The modification process is also one of the important considerations for selecting a surface modifier, such as temperature, pressure and environmental factors. All organic surface modifiers will decompose at a certain temperature. For example, the boiling point of silane coupling agent varies between 100 and 310 °C depending on the type. Therefore, the decomposition temperature or boiling point of the selected surface modifier is preferably higher than the processing temperature during application.   Currently, the surface modification process mainly adopts two methods: dry method and wet method. For the dry process, there is no need to consider its water solubility, but for the wet process, the water solubility of the surface modifier must be considered, because only when it is soluble in water can it fully contact and react with the powder particles in a wet environment. For example, stearic acid can be used for dry surface modification of calcium carbonate powder (either directly or after dissolving in an organic solvent). However, in wet surface modification, if stearic acid is added directly, it is not only difficult to achieve the expected surface modification effect (mainly physical adsorption), but also the utilization rate is low. The surface modifier is seriously lost after filtration, and the organic matter emission in the filtrate exceeds the standard. Other types of organic surface modifiers also have similar situations. Therefore, for surface modifiers that cannot be directly soluble in water but must be used in a wet environment, they must be saponified, ammonized or emulsified in advance so that they can be dissolved and dispersed in aqueous solution.   (4) Price and environmental factors   Finally, the selection of surface modifiers should also consider price and environmental factors. On the premise of meeting the application performance requirements or optimizing the application performance, try to use a cheaper surface modifier to reduce the cost of surface modification. At the same time, pay attention to choosing a surface modifier that does not pollute the environment. 2. Dosage of surface modifier   Theoretically, the dosage required to achieve monolayer adsorption on the particle surface is the optimal dosage, which is related to the specific surface area of ​​the powder raw material and the cross-sectional area of ​​the surface modifier molecule, but this dosage is not necessarily the dosage of the surface modifier when 100% coverage is achieved. For inorganic surface coating modification, different coating rates and coating layer thicknesses may show different characteristics, such as color, gloss, etc. Therefore, the actual optimal dosage should be determined through modification tests and application performance tests. This is because the dosage of the surface modifier is not only related to the dispersion of the surface modifier during surface modification and the uniformity of coating, but also to the specific requirements of the application system for the surface properties and technical indicators of the powder raw materials.   For wet modification, the actual coating amount of the surface modifier on the powder surface is not necessarily equal to the dosage of the surface modifier, because there is always a part of the surface modifier that fails to react with the powder particles and is lost during filtration. Therefore, the actual dosage should be greater than the dosage required to achieve monolayer adsorption. 3. Method of using surface modifiers   The method of using surface modifiers is one of the important components of the surface modifier formula and has an important impact on the surface modification effect of powders. A good method of use can improve the dispersion degree of surface modifiers and the surface modification effect of powders. On the contrary, improper method of use may increase the amount of surface modifiers used and the modification effect cannot achieve the expected purpose.   The method of using surface modifiers includes preparation, dispersion and addition methods as well as the order of adding when using more than two surface modifiers.   (1) Preparation   The preparation method of surface modifiers depends on the type of surface modifiers, modification process and modification equipment. Different surface modifiers require different preparation methods. For example, for silane coupling agents, silanols are bonded to the surface of powders. Therefore, to achieve a good modification effect (chemical adsorption), it is best to hydrolyze before adding. For other organic surface modifiers that need to be diluted and dissolved before use, such as titanate, aluminate, stearic acid, etc., corresponding organic solvents such as anhydrous ethanol, toluene, ether, acetone, etc. should be used for dilution and dissolution. For organic surface modifiers such as stearic acid, titanate, aluminate, etc. that are not directly soluble in water used in the wet modification process, they should be saponified, ammonized or emulsified in advance to become products that can be dissolved in water.   (2) Addition method   The best way to add surface modifiers is to make the surface modifiers and powders contact evenly and fully to achieve a high degree of dispersion of the surface modifiers and uniform coating of the surface modifiers on the particle surface. Therefore, it is best to use a continuous spraying or dripping (addition) method linked to the powder feeding speed. Of course, only a continuous powder surface modifier can achieve continuous addition of surface modifiers.   The preparation method of inorganic surface modifiers is relatively special, and it is necessary to consider multiple factors such as solution pH, concentration, temperature, and additives. For example, when titanium dioxide is coated on the surface of muscovite, titanyl sulfate or titanium tetrachloride must be hydrolyzed in advance.   (3) Order of adding drugs   When more than two surface modifiers are used to treat the powder, the order of adding drugs also has a certain influence on the final surface modification effect. When determining the order of adding surface modifiers, we must first analyze the role of each of the two surface modifiers and the mode of action on the powder surface (whether it is mainly physical adsorption or chemical adsorption). Generally speaking, the surface modifier that plays the main role and is mainly chemically adsorbed is added first, and the surface modifier that plays the secondary role and is mainly physical adsorption is added later.   For example, when a coupling agent and stearic acid are mixed, generally speaking, the coupling agent should be added first and the stearic acid should be added later, because the main purpose of adding stearic acid is to enhance the hydrophobicity and lipophilicity of the powder and reduce the amount of coupling agent and the cost of the modification operation.

Generalmente, de acuerdo con el mecanismo de desgaste y la interacción entre materiales y abrasivos y materiales y materiales en el sistema de desgaste, los principales tipos de desgaste se pueden dividir en desgaste abrasivo, desgaste adhesivo, desgaste por erosión, desgaste por fatiga, desgaste corrosivo y desgaste por fricción. etc. 6 tipos.   1.1 Desgaste abrasivo   Las partículas duras o protuberancias que entran entre las superficies de fricción desde el exterior crean muchos surcos en la superficie del material más blando, lo que resulta en una migración del material y un fenómeno de desgaste llamado desgaste abrasivo.   Los principales factores que influyen en este tipo de desgaste: en la mayoría de los casos, cuanto mayor sea la dureza del material, mejor será la resistencia al desgaste; la cantidad de desgaste aumenta con el aumento del tamaño medio de las partículas de desgaste; la cantidad de desgaste aumenta con el aumento de la dureza de las partículas abrasivas. Aumentar etc   1.2 Desgaste del adhesivo:   Desgaste causado por la caída o transferencia del material de una superficie a otra debido a la soldadura en fase sólida cuando las superficies de contacto se mueven entre sí.   Los principales factores que afectan el desgaste del adhesivo: Los materiales de pares de fricción similares son más fáciles de adherir que los materiales diferentes. El tratamiento de la superficie (como tratamiento térmico, pulverización, tratamiento químico, etc.) puede reducir el desgaste del adhesivo; los materiales quebradizos tienen mayor resistencia a la adhesión que los materiales plásticos; la superficie del material es rugosa Cuanto menor sea el valor del grado, mayor será la capacidad antiadherente; controlar la temperatura de la superficie de fricción y utilizar lubricantes puede reducir el desgaste del adhesivo, etc.   1.3 Erosión o Desgaste Erosivo   Cuando un fluido que contiene partículas fluidas (sólidas, líquidas o gaseosas) impacta la superficie de un material, se produce un fenómeno de desgaste que se denomina desgaste por erosión.   Los principales factores que afectan el desgaste por erosión son la velocidad del impacto y el ángulo de las partículas que fluyen.   1.4 Desgaste por fatiga   Cuando dos materiales se mueven entre sí (rodando o deslizándose), el área de contacto se ve afectada repetidamente por una tensión cíclica. Cuando la tensión cíclica excede la resistencia a la fatiga de contacto de los materiales, se forman grietas por fatiga en la superficie de contacto o en algún lugar debajo de la superficie, lo que provoca que la capa superficial se caiga parcialmente. Este fenómeno se denomina desgaste por fatiga.   Los principales factores que afectan al desgaste por fatiga: cuanto mayor es la dureza superficial de la pieza, menor es el riesgo de grietas por fatiga; reducir la rugosidad de la superficie puede mejorar la vida útil de la pieza; El aceite lubricante de alta viscosidad puede mejorar la capacidad de resistir el desgaste por fatiga, lo que es beneficioso para mejorar la vida útil. esperanza de vida, etc.   1.5 Desgaste corrosivo   Durante el proceso de fricción, se produce una reacción química o electroquímica entre la superficie de fricción y el medio circundante, lo que resulta en la pérdida de materiales de la superficie, lo que se denomina desgaste por corrosión.   Los principales factores que afectan el desgaste por corrosión: las propiedades de los medios corrosivos (como ácidos, álcalis, sales), las propiedades de la película de óxido en la superficie de las piezas y la temperatura y humedad ambiente.   1.6 Desgaste por traste   El desgaste por fricción se produce cuando las superficies metálicas que se presionan entre sí vibran en pequeñas amplitudes, lo que provoca que se produzcan partículas de desgaste oxidadas en la superficie de contacto, que son difíciles de eliminar de las piezas de contacto.   Los principales factores que afectan el desgaste por fricción: El desgaste de materiales similares es mucho más grave que el de materiales diferentes.

La limpieza del pulverizador de chorro es un indicador importante en la operación de trituración. Debido a que el pulverizador de chorro está en contacto directo con el material, la limpieza del pulverizador de chorro es muy importante y afecta directamente la calidad del material. Después de su uso, se debe limpiar. Simplemente límpielo y límpielo con cuidado para que sea más conveniente para el próximo uso y no afecte la calidad de los materiales. A continuación, el editor de Longyi Equipment le indicará algunos métodos para limpiar el molinillo.   1. Una vez completada la producción del molino de chorro, apague la energía y envíe todos los materiales en producción a la estación intermedia de acuerdo con los procedimientos de entrada y salida de materiales. Colgar un cartel indicando que el equipo está listo para su limpieza.   2. Abra la trituradora de productos químicos y mueva la bolsa recolectora, la rejilla, el conducto de aire desmontable, etc. al fregadero de la sala limpia. Vierta aproximadamente 2/3 del volumen de agua tibia a 30 ~ 40 ℃ en el fregadero, déjelo en remojo durante 10 a 30 minutos y luego lave la parte delantera y trasera de la bolsa recolectora de polvo repetidamente con agua corriente hasta que la bolsa recolectora de polvo esté limpia;   3. Utilice un trapo especial limpio humedecido en agua tibia y limpie la entrada de material de la trituradora, la cavidad interior de la trituradora, la salida de material y la cámara de recolección de polvo repetidamente hasta que estén limpios. 4. Lave la pantalla y el conducto de aire con un cepillo suave para aclarar el líquido del agua y enjuáguelos tres veces con agua ionizada. Secar en una zona limpia al mismo nivel que la sala de trituración y reservar.   5. Utilice un desionizador para limpiar y limpiar minuciosamente la pared interior del triturador de productos químicos, el tubo de transporte de polvo y el separador ciclónico.   6. Seque las piezas anteriores con una toalla limpia y seca y luego límpielas con etanol al 75%.   7. Limpie el piso del quirófano, el gabinete de distribución de energía, el motor y el gabinete de operación. Después de que las bolsas y las pantallas estén secas, limpie y enjuague el piso del quirófano con regularidad para garantizar que no haya acumulación de polvo o agua en el suelo.   Lo anterior trata sobre cómo limpiar el pulverizador de chorro. Espero que pueda ayudarte. Para obtener más información, ¡continúa siguiéndonos!