Surface Modifiers, Processes and Equipment For Silicon micropowder

Silicon micro powder is a silica powder material made of natural quartz ore, fused silica, etc. as raw materials, which is processed by grinding, precision classification, and impurity removal. It has high insulation, high thermal conductivity, high thermal stability, Acid and alkali resistance, wear resistance, low thermal expansion coefficient, low dielectric constant and other characteristics, are widely used in the copper clad laminate industry, epoxy plastic packaging industry, electrical insulation material industry and adhesive industry.

In order to improve the interface between silicon micropowder and organic polymer materials and improve its application performance, it is generally necessary to modify the surface of silicon micropowder. The key to the surface modification of silica micropowder is how to make the modifier uniformly disperse on the particle surface, and at the same time ensure the chemical bonding conditions between the modifier and the particle surface. Ultra-fine silicon powder has a large specific surface area, and how to make the modifier evenly dispersed on the particle surface is a difficult problem that plagues silicon powder manufacturers.

1. Surface modifier

Silane coupling agent is the most commonly used modifier for surface modification of silicon micropowder. It can convert the hydrophilicity of silicon micropowder into an organic hydrophilic surface, and can also improve the wettability of organic polymer materials to its powder. Make the silicon micropowder and the organic polymer material achieve a firm covalent bond interface.

However, the application effect of the silane coupling agent is related to the selected type, dosage, hydrolysis situation, substrate characteristics, application occasions, methods and conditions of organic polymer materials. Therefore, in order to use a silane coupling agent well, it is necessary to carefully study its structure, properties and the mechanism of its interaction with silicon micropowder, so as to correctly select and use a good silane coupling agent.

2. Surface modification process

Because the dry process is relatively simple and the production cost is relatively low, at present, the surface modification of silicon micropowder in China basically adopts the dry process. However, the specific surface area of ​​the ultra-fine silicon powder is relatively large, and the mechanical dispersion of the equipment alone cannot make the treatment agent evenly dispersed on the surface of the particles, so the effect of dry modification is relatively poor.

Wet modification is carried out under liquid phase conditions. The modifier can disperse the particle surface relatively uniformly. Generally speaking, the modification effect is good. However, the wet modification process is complicated, requires drying and depolymerization processes, and the production cost is relatively high. high, but the wet modification effect is better.

3. Surface modification equipment

The selection of surface modification equipment is a crucial part of the surface modification of silicon micropowder. When selecting surface modification equipment, the following requirements should be considered:

At present, there are many surface modification equipments in China, but some surface modification equipments are not manufactured in accordance with the mechanism and process requirements of surface modification of silicon powder, resulting in poor surface modification effect. Therefore, it is necessary to modify the purchased modified equipment. Only after the equipment is transformed and matched can it achieve better results.

Finally, it is stated that in order to do a good job in the surface modification of silica micropowder, it is necessary to carefully understand the structure and properties of the surface modifier based on the mechanism of surface modification, and at the same time consider the substrate and main formula of downstream organic polymer products. And technical requirements, after comprehensive consideration, select a reasonable modifier, and on this basis, determine the surface modification process and equipment.

by ALPA

What non-metallic mineral powders are contained in girls' favorite cosmetics?

Liquid foundation is the most basic makeup product that girls will use. It is light in texture, easy to apply, and less greasy. It is a very popular foundation cosmetic today. It is suitable for most skins. Nowadays, many liquid foundations are used for beauty and skin care. Combined, it becomes a multifunctional product.

1. Talc Powder Talc powder can make the liquid foundation spread smoothly on the skin and make the skin smooth.
2. Kaolin clay and titanium dioxide make the liquid foundation have strong covering power, and can eliminate the glitter of talc powder.
3. Calcium carbonate and magnesium carbonate can absorb sweat and oil on the surface of the skin, and also have the effect of eliminating talc glitter.
4. Pigments are generally mixed with inorganic pigments and organic pigments. Commonly used inorganic pigment iron oxide is mixed with red or orange organic pigment to become the pigment of foundation.
5. Zinc stearate and zinc myristate make the liquid foundation have strong adhesion.
6. The binder makes the above-mentioned various foundation components melt and form, mainly composed of mineral oils such as animals and plants, liquid paraffin, or synthetic fat oils.

7. Other ingredients such as preservatives, antioxidants and spices, etc., and also have plant ingredients, such as seaweed extract, yam extract, vitamins, elastin, pearl powder, etc., which have the effect of repairing soft skin, moisturizing and whitening.

by ALPA

8 Applications of Ultrafine Grinding Technology in Food Industry

Due to the development of micronization of particles, the material surface has unique physical and chemical properties, such as good solubility, decomposition, adsorption, chemical activity, etc. Ultrafine technology involves the preparation, drying, dispersion, characterization, The process of grading, surface modification, filling and granulation is not only used in chemical industry, electronics, information, biology, building materials, national defense, environmental protection and other industries, but also in textile, food, medicine and other industries closely related to people's daily life. application.

With the advancement of science and industrial technology, ultrafine grinding technology, as an engineering discipline, plays a pivotal role in the development of the national economy. Due to the development of micronization of particles, the material surface has unique physical and chemical properties, such as good solubility, decomposition, adsorption, chemical activity, etc. Ultrafine technology involves the preparation, drying, dispersion, characterization, The process of grading, surface modification, filling and granulation is not only used in chemical industry, electronics, information, biology, building materials, national defense, environmental protection and other industries, but also in textile, food, medicine and other industries closely related to people's daily life. application.

Application of Ultrafine Grinding Technology in Food Industry

1. Soft drink processing

2. Fruit and vegetable processing

3. Grain and oil processing

4. Processing of aquatic products

5. Functional food processing

6. Condiment processing

7. Processing of fresh bone meal (mud) of livestock and poultry products

8. Ice cream processing of cold food products

Usually, the pulverization process of ultrafine pulverization technology has little effect on the original nutrients in the raw materials, and the prepared powder has good uniformity. Performance has a multifaceted impact. At present, ultrafine pulverization technology is more and more used in the production of many functional foods at home and abroad. It makes the raw materials that could not be fully digested, absorbed or utilized to be reused, thereby obtaining a variety of functional foods and new foods. The production materials increase the variety of food and improve the utilization rate of natural biological resources.

by ALPA

Dry Grinding Of Ultrafine Powder Below 2.5 Microns and PM 2.5

1. Why should we start with PM2.5 for the relationship between haze and dry classification of ultrafine powder? In my opinion, 2.5 microns is a special data for split particles, and now we all know a meteorological parameter: PM2.5. Refers to the particles in the ambient air with an aerodynamic equivalent diameter of less than or equal to 2.5 microns. Compared with coarser atmospheric particles, PM2.5 has a small particle size, a large specific surface area, strong activity, and has the characteristics of long residence time in the atmosphere and long transportation distance. It is a fine particle that is difficult to overcome. Medium and relatively large particles follow different motion laws. The ultrafine powder below 2.5 microns has a more special motion law, which has become a difficult problem for powder scientists in various countries in the production of dry powder. Below this scale, it is difficult to classify the particles in the air, that is to say, it is still difficult to separate powder particles below 2.5 microns in the modern powder industry. Therefore, the study of PM2.5 has practical guiding significance for the production of modern ultrafine powder particles for the continuous dry production process of split particles above 6000 mesh.

2. Review and Prospect of the Development of Powder Classification Technology Another interesting data is PM25, here I refer to powder particles with an equivalent diameter of 25 microns or more. In the classification process of powder particles, the screening process is widely used in the production of various powders, and is commonly seen in daily life, and has a very wide range of applications in many large industrial sectors such as building materials industry and food processing. In powder production terms, 25 microns is approximately the pore size of a 600 mesh screen. Professional manufacturers engaged in ultrasonic vibration sieves all know: 600 mesh is a data close to the limit for general powder particle sieving, and it is difficult to mechanically sieve fine powders. Is this a coincidence or a law, we don't know yet, the existence is the truth, wait for more people to study it.

There may be a more meaningful data: 250 nanometers. The so-called nanotechnology refers to a new technology that studies the motion laws and characteristics of electrons, atoms and molecules in the scale of 0.1 to 100 nanometers. Since the distribution of ultrafine powder is within a certain range, many scholars believe that particle powder below 500 nanometers is a scale limit of nanotechnology. At this time, most of the particles have reached below 100 nanometers, so it also appears Special physicochemical properties of nano-sized particles. In my opinion, D97 has a physical size of 500 nanometers. It will be another powder peak that is not easy to climb in powder technology grinding and grading, and it will be another new direction for powder development in the future. The general academic community believes that for solid powder or fiber, when its one-dimensional size is less than 100nm, that is, it reaches nanometer size, it can be called a so-called nanomaterial. For ideal spherical particles, when the specific surface area is greater than 60m2/g, its diameter will be smaller than 100nm, reaching nanometer size.

3. Study the practical significance of dry classification of ultrafine powders below 2.5 microns. Powder particles below 2.5 microns will show many characteristics that cannot be achieved by wet methods using the dry production process. It is also the key technology for powder production in some industries.

However, powder particles below 2.5 microns are like a lively, naughty and super energetic urchin in dry powder production, and people seem to have no way to tune them. The smog pollution of PM2.5 has disturbed people's sleep and sleep, and caused immeasurable economic and people's health losses. However, for our professionals engaged in ultra-fine powder materials, this is also the best textbook and free laboratory for studying ultra-fine powder materials. Studying the laws of its production, grading, collection and dissipation will not only affect today's The ultrafine powder industry has practical guiding significance, and also has great theoretical guiding significance for the governance of haze.

Dry production of powder particles below 2.5 microns is a forward-looking production project in the modern powder industry. Countries are carrying out basic theories and production processes with broad industrial prospects. It has unlimited uses in many fields such as modern manufacturing, national defense technology, composite materials, traditional Chinese medicine processing, ceramic industry, environmental protection industry, medical and health care and so on.

by ALPA

The working method of traditional Chinese medicine ultrafine grinding technology

The working principle of traditional Chinese medicine ultrafine pulverization technology generally includes impact, collision, friction, shearing, grinding and simultaneous fracture of materials. When choosing the pulverization method, it should be determined according to the nature of the material and the required pulverization degree: the hard materials with large or medium particle size are crushed and impacted; the hard materials with small particle size are crushed, impacted and milled; The ductile or mud-like materials are sheared, crushed and milled, and the ductile materials are sheared or rapidly struck.

Equipment for ultra-fine grinding technology of traditional Chinese medicine

There are many kinds of traditional Chinese medicine ultrafine grinding equipment. Currently there are three main categories of applications: vibration grinding. Air flow type ultra-fine pulverizer, mechanical ultra-fine pulverizer. Because the vibration mill has high working efficiency, the jet mill has no pollution to the material during the pulverization process, and the product fineness is high, so these two types of equipment are widely used.

1. Vibration mill

Vibration mill is a high-frequency vibration type ultra-fine grinding equipment. Its working principle is: the body is supported by a spring, and the main shaft with an eccentric block makes it vibrate. During operation, the medium and the material vibrate and grind the material together. It is characterized by high filling rate of medium, many times of action per unit time, and small particle size of powder. Evenly distributed, suitable for crushing most Chinese herbal medicines. This equipment can also be combined with low-temperature technology to obtain ultrafine powder with narrow particle size distribution and good fluidity, which solves the problem of temperature rise of the vibration mill. At present, the widely used vibration mill is Shandong Beili BMF series, and other new and improved equipment have been launched recently. Such as Zhejiang Fengli's MTM type impact mill, Shanghai Xieke's HGM type heavy pressure grinding type super emblem mill, and Beijing Huanya Tianyuan's HMB type three-ring medium-speed micro-powder mill. The disadvantage of this method is that the particle size of the product is related to the maximum particle size of the feed. When the maximum particle size of the feed is about 10 mm, the product particle size is greater than 10um; Production capacity declines.

2. Air jet mill

The jet mill is called a fluid energy mill. Its working principle is: the supersonic airflow makes the material particles violently collide and rub against each other, and the airflow has a direct shearing effect on the material, and then the purpose of pulverization is achieved through appropriate classification. There is no associated heat in the crushing process of this type of equipment, and the crushing temperature is low, which is suitable for low melting point and heat-sensitive medicinal materials. The crushing particle size can reach 1-10um, and it is no pollution to the material. It is the finest physical processing method that can be achieved at present. The shortcomings of this equipment are high equipment manufacturing and manufacturing costs, large energy consumption, low energy utilization rate and high production costs. At present, there are 5 types of jet mills: flat type, single-spray type, circulating tube type, counter-spray type and fluidized bed type. However, it is generally believed that the jet mill is difficult to crush fibrous and tough Chinese medicines, and there is a relatively high-speed air flow during the crushing operation, which takes away the volatile components of the medicine and causes the loss of efficacy, so it is only suitable for the crushing of brittle Chinese medicines.

3. Ultrafine Impact

The working principle of the ultrafine Impact is: through the high-speed movement of the mechanical parts and the medium, the raw medicinal powder is impacted, sheared and other external forces to achieve the purpose of pulverization. The advantages of this equipment are that it is simple and convenient, and the applicable particle size range for feeding is large. The disadvantage is that the equipment is easy to heat up, the finer the material is pulverized, the more severe the wear of the parts, the wear particles directly contaminate the material, and the lower limit of the powder particle size can only reach about 20 um, which limits the wide application of this equipment.

Due to the limitations of the above three types of equipment, some scholars are now committed to the development of ultra-fine pulverizing units that combine mechanical pulverization and jet pulverization, as well as ultra-low temperature cryogenic pulverizers. However, due to the high cost, the application scope of the new device is far less than the above three devices.

by ALPA

Quartz Sand & Quicklime, High-end New Building Plate: Calcium Silicate Plate

Calcium silicate board is an inorganic building board with high strength and stable performance, which is made of siliceous materials, calcium materials and reinforcing fibers as the main raw materials.

It has the advantages of fire prevention, thermal insulation, anti-corrosion and moth-proof, waterproof and moisture-proof, sound insulation and sound absorption, light weight and high strength, green and harmless, etc. It is more energy-saving, environmentally friendly, earthquake-resistant and impact-resistant than traditional boards, and can be widely used in interior and exterior wall insulation decoration of buildings , ceiling and cabin partitions, billboards and other fields, and the design and installation of strong plasticity, saving time and labor.

In recent years, with the increasing promotion of prefabricated buildings across the country, the market demand for calcium silicate boards in various places has risen. Whether it is used for composite lightweight wall panels, or directly used for interior and exterior wall insulation decoration, ceilings, floor linings, calcium silicate boards have become an important "role" in prefabricated housing construction.

Quartz sand is one of the most important raw materials in calcium silicate products, accounting for 40% of the raw material quality of calcium silicate boards. The purity of SiO2 in quartz sand has a great influence on the formation of toble mullite crystals during the hydration reaction. Quartz powder that is not involved in chemical reaction also acts as an aggregate in cement cement. However, the wet grinding energy of quartz sand is very large. In order to reduce the energy consumption of wet grinding of quartz sand and use more industrial waste, quartz sand with SiO2 content higher than 90% is preferred in the production of calcium silicate board, and it can be appropriately mixed A certain amount of fly ash to reduce production costs.

Calcium silicate board has good market prospects and faces huge development opportunities and challenges: (1) Necessary measures should be taken in the production process of calcium silicate board to achieve green production and improve production efficiency under the premise of protecting the environment ; (2) To enrich the production raw materials of calcium silicate board, use low-calcium fly ash or quartz sand tailings, other industrial waste residues with high silicon content to replace all or part of the quartz sand, thereby reducing production costs and improving resource utilization; ( 3) In order to meet the needs of the market, the types of calcium silicate board products should be enriched and the durability of the products should be improved.

by ALPA

What are the advantages of ultrafine powder grinding technology?

1. Fast temperature control

Ultrafine pulverization technology can use supersonic jet pulverization, cold pulp pulverization and other methods, which can avoid local overheating and other phenomena during the pulverization process, and can even be carried out at low temperature, and the pulverization speed is fast, so it can maximize the retention of powder. The biological activity of the body and various nutritional components can be reduced, and the loss of effective components can be reduced, which is beneficial to the development and preparation of high-quality products. Therefore, the ultrafine pulverization technology is not only suitable for the pulverization of fibrous materials (especially suitable for the pulverization of materials containing aromatic and volatile components), but also can be used for medium, low and ultra-low temperature pulverization according to the needs of different materials. Material properties and processing requirements to achieve better product results.

2. Small particle size

The distribution of the external force for ultrafine pulverization on the raw material is relatively uniform. The grading system not only strictly limits the large particles, but also avoids excessive crushing of materials, and can obtain ultrafine powder with uniform particle size distribution.

3. Reduce pollution

The traditional pulverization method has poor sealing and is prone to pollution, while the ultrafine pulverization is carried out in a closed system, which not only avoids the pollution of the surrounding environment by fine powder, but also prevents the dust in the air from contaminating the product. The use of this technology in food and healthcare products can control microbial and dust contamination. At the same time, since the ultra-fine pulverization process is a purely physical process, no other impurities will be mixed, which also makes the processed Chinese herbal medicines pure natural, ensuring the integrity and safety of the raw materials.

by ALPA