Sodium silicate（HLNAP-3）

What is the effect of the pulverization process (such as airflow mill or mechanical mill) of Modulus (M): 2.9±0.1 powdered sodium silicate on the particle size distribution?

In the chemical industry, powdered sodium silicate is an important inorganic silicon product and is widely used due to its unique physical and chemical properties. Tongxiang Hengli Chemical Co., Ltd specializes in the production of inorganic silicon products, including more than 30 varieties such as sodium silicate and potassium silicate. Among them, powdered water glass (model HLNAP-3, modulus 2.9±0.1) is a product made by drying and spraying liquid water glass. It has significant advantages such as high content, low moisture, and easy transportation and storage. It is widely used in detergents, cement quick-drying additives and other fields. In the production process of powdered sodium silicate, the pulverization process is one of the key factors affecting its particle size distribution. Different pulverization processes (such as airflow mill or mechanical mill) will have different effects on the particle size distribution of the product, thereby affecting the performance and application effect of the product.

1. Overview of powdered sodium silicate

Powdered sodium silicate, also known as instant powdered water glass, is a solid product made from liquid water glass through drying, crushing and other processes. Compared with liquid water glass, it has significant advantages such as high content, low water content, easy transportation and storage, saving packaging and transportation costs, and can be quickly dissolved and used on site. Taking Tongxiang Hengli Chemical Co., Ltd's instant powdered sodium silicate - HLNAP-3 as an example, its modulus (M) is 2.9±0.1, the silicon dioxide content (SiO₂) is between 55.0-60.0%, the Na₂O content is between 22.0-26.0%, the bulk density is 0.69Kg/L, the dissolution rate (30℃) is ≤240S, and the particle size (100 mesh pass rate%) is ≥95. These performance indicators make it widely used in detergents, cement quick-drying additives, industrial plugging, high temperature resistant binders and other fields.

2. Classification and principle of crushing process

The crushing process is the process of crushing large pieces of material into the required particle size. According to the crushing principle and equipment, common crushing processes include air flow mill and mechanical mill.
(I) Air flow mill
The air flow mill, also known as air flow mill, is a device that uses high-speed airflow (such as compressed air, superheated steam or other gases) to make material particles collide and rub against each other and between particles and the wall of the device to achieve crushing. Its working principle is: compressed air forms a high-speed airflow through the nozzle, and the material enters the crushing chamber driven by the high-speed airflow. In the crushing chamber, there are violent collisions, frictions and shearing between material particles, between particles and airflow, and between particles and the wall of the device, so that the material is crushed. The crushed material enters the classification chamber with the airflow. In the classification chamber, the fine particles that meet the particle size requirements are separated by centrifugal force and airflow, while the coarse particles return to the crushing chamber to continue crushing until the required particle size requirements are reached.
The air flow mill has the following characteristics:
The mechanical force on the material during the crushing process is small, and it is not easy to overheat. It is suitable for the crushing of heat-sensitive, low melting point and high purity materials.
The particle size distribution of the crushed material is narrow, the particle size uniformity is good, and micron-level or even nano-level crushing can be achieved.
The equipment has a simple structure, is easy to clean and maintain, and is suitable for crushing operations in a sterile and pollution-free environment.
It has high crushing efficiency, can be produced continuously, and has a large production capacity.
(II) Mechanical mill
Mechanical mill is a device that uses mechanical force (such as impact force, grinding force, shear force, etc.) to break material particles. Common mechanical mills include ball mills, Raymond mills, hammer mills, etc. Taking the ball mill as an example, its working principle is: a certain number and size of grinding media (such as steel balls, porcelain balls, etc.) are installed in the cylinder of the ball mill. When the cylinder rotates, the grinding media is lifted to a certain height under the action of centrifugal force and friction, and then falls in a parabolic shape, which has an impact and grinding effect on the material, so that the material is crushed. During the crushing process, the material is continuously impacted and ground by the grinding media, and is also continuously turned and mixed in the cylinder, thereby achieving material crushing and homogenization.
Mechanical mill has the following characteristics:
It has a wide range of applications and can be used to crush materials of various hardness and properties.
The equipment has a simple structure, low cost and easy maintenance.
The crushing efficiency is relatively low, and heat is easily generated during the crushing process, which may have a certain impact on the performance of the material.
The particle size distribution of the crushed material is wide and the particle size uniformity is poor.

3. The influence of different crushing processes on the particle size distribution of powdered sodium silicate

(I) The influence of airflow mill on the particle size distribution of powdered sodium silicate
Narrow particle size distribution and good uniformity: Since the airflow mill uses high-speed airflow to make the material particles collide and rub against each other to achieve crushing, the force on the material particles during the crushing process is relatively uniform, so the particle size distribution of the crushed powdered sodium silicate is narrow and the particle size uniformity is good. For example, during the crushing process of the airflow mill, the material particles collide with each other at a high speed under the drive of the high-speed airflow. The impact force and shear force generated during the collision can make the material particles evenly broken, thereby obtaining a product with a relatively concentrated particle size distribution.
Can achieve ultra-fine crushing: The airflow mill has a high crushing efficiency and can achieve micron-level or even nano-level crushing. For powdered sodium silicate with modulus (M): 2.9±0.1, the airflow mill pulverization process can crush its particle size to a smaller range, such as below the micron level, thereby increasing the specific surface area and reactivity of the product, so that it can play a better role in the application process. For example, in the field of detergents, ultrafine powdered sodium silicate can be better mixed with other ingredients to improve the washing effect of detergents; in the field of cement quick-drying additives, ultrafine powdered sodium silicate can react with cement faster and shorten the setting time of cement.
Strong controllability of particle size distribution: The airflow mill can control the material's pulverization particle size and particle size distribution by adjusting process parameters such as airflow velocity, pulverization chamber pressure, and classifier speed. For example, increasing the airflow velocity can increase the collision energy between material particles, thereby improving pulverization efficiency and reducing the particle size after pulverization; adjusting the classifier speed can change the size of the centrifugal force in the classification chamber, thereby controlling the particle size range of the separated fine particle material and achieving precise control of the particle size distribution.
(II) The influence of mechanical grinding on the particle size distribution of powdered sodium silicate
The particle size distribution is wide and the uniformity is poor: Mechanical grinding mainly uses mechanical force (such as impact force, grinding force, etc.) to break the material particles. The force acting on the material particles during the crushing process is uneven, so the particle size distribution of the powdered sodium silicate after crushing is wide and the particle size uniformity is poor. For example, in the ball mill crushing process, there is a certain randomness in the movement trajectory and impact force of the grinding medium, which leads to inconsistent degree of material particle crushing, resulting in a large difference in particle size. Some particles are crushed very finely, while others are still large, making the product's particle size distribution range wide.
Large crushing particle size: Compared with air flow mills, the crushing efficiency of mechanical mills is relatively low, and it is difficult to achieve ultra-fine crushing. The powdered sodium silicate after crushing has a larger particle size. For powdered sodium silicate with a modulus (M): 2.9±0.1, the mechanical mill crushing process can usually only crush its particle size to a range of tens of microns or even coarser, which will affect the performance and application range of the product to a certain extent. For example, in the field of precision casting, fine powdered sodium silicate is required to ensure the surface quality and precision of castings, while the products crushed by mechanical grinding may not meet the requirements.
Poor controllability of particle size distribution: The process parameters of mechanical grinding are relatively fixed, and the controllability of particle size distribution is poor. Although the crushing effect can be affected by adjusting the size, quantity, cylinder speed and other parameters of the grinding media, the range of such adjustment is limited, and it is difficult to achieve precise control of particle size distribution. Therefore, the particle size distribution of powdered sodium silicate crushed by mechanical grinding is often not stable enough and is easily affected by factors such as material properties and equipment operation status.

4. Factors affecting the effect of crushing process on particle size distribution

(I) Material properties
The hardness, brittleness, humidity and other properties of the material will affect the effect of the crushing process on particle size distribution. For materials with higher hardness and greater brittleness, they are more easily crushed during the airflow grinding process, and the particle size distribution is easier to control; for materials with lower hardness and greater toughness, mechanical grinding may be more suitable, but the particle size distribution may be wider. In addition, the humidity of the material will also affect the crushing effect. Materials with too high humidity are prone to agglomeration during the crushing process, resulting in uneven particle size distribution.
(II) Equipment parameters
Different crushing equipment has different parameter settings, such as the air flow velocity, crushing chamber pressure, and classifier speed of the air flow mill, and the size, quantity, and cylinder speed of the grinding media of the mechanical mill. These parameters will directly affect the crushing effect and particle size distribution of the material. For example, in the air flow mill, increasing the air flow velocity can increase the collision energy of the material particles, thereby reducing the particle size, but too high an air flow velocity may cause increased equipment wear and increased energy consumption; in the mechanical mill, increasing the number of grinding media and reducing the diameter of the grinding media can improve the crushing efficiency, but it will also increase the load and wear of the equipment.
(III) Production process
The rationality of the production process will also affect the impact of the crushing process on the particle size distribution. For example, in the crushing process, factors such as the material feeding speed and crushing time will affect the crushing effect. If the feeding speed is too fast, the material will stay in the crushing chamber for too short a time, which will lead to insufficient crushing and widen the particle size distribution. If the crushing time is too long, the material will be over-crushed, which will increase energy consumption and equipment wear. At the same time, it may also cause the material to agglomerate and affect the particle size distribution.

5. Selection and optimization of crushing process

(I) Select crushing process according to product requirements
Different application fields have different requirements for the particle size distribution of powdered sodium silicate. For example, in the fields of electronics and precision casting, powdered sodium silicate with narrow particle size distribution and uniform particle size is usually required to ensure the performance and quality of the product. At this time, the air flow mill crushing process should be preferred; in some fields where the particle size requirements are not very high, such as agriculture and papermaking, mechanical mill crushing process can be selected to reduce production costs. When Tongxiang Hengli Chemical Co., Ltd produces powdered sodium silicate, it can reasonably select the crushing process according to different product models and application requirements to meet the diverse needs of customers.
(II) Optimize equipment parameters and production process
In order to obtain the ideal particle size distribution, it is necessary to optimize the parameters and production process of the crushing equipment. For air flow mills, the best crushing conditions can be found by adjusting parameters such as air flow velocity, crushing chamber pressure, and classifier speed to achieve the best particle size distribution; for mechanical mills, crushing efficiency and particle size uniformity can be improved by selecting appropriate grinding media, adjusting the number and diameter of grinding media, and controlling parameters such as cylinder speed. At the same time, it is also necessary to reasonably control the feeding speed and crushing time of the material to ensure the stability and reliability of the crushing process.
(III) Combining multiple crushing processes
In actual production, in order to obtain better crushing effects, multiple crushing processes can be combined. For example, a mechanical mill is first used to coarsely crush the material, and then a jet mill is used for fine crushing and classification. This can give full play to the advantages of the two crushing processes, which not only improves the crushing efficiency, but also ensures the uniformity of particle size distribution. This combined crushing process has certain application prospects in the production of some powdered sodium silicate with high particle size requirements.