SMP Agitator bead mill

Sand mill is also called bead mill. A type of grinding and dispersing equipment for solid-liquid phase dispersion of powdery materials and liquid materials. As the grinding medium, a sand mill was initially used, so it was called a sand mill; later, glass beads were used, so it was also called a bead mill. The grinding media currently used are sand grains with rounded corners, beads made of various glass or wear-resistant materials, steel balls, and steel shavings. This kind of wet ultrafine grinding equipment is widely used in the dispersion and grinding of pigments in the ink production process.

A rotating shaft is axially inserted into the vertical or horizontal cylinder, and several grinding discs, rings, or pins are installed radially on the rotating shaft. The cylinder is filled with grinding media with a particle size of 0.6-2mm. The simplified version is equipped with a jacket with cooling water in the middle to absorb and dissipate the heat generated during the grinding and dispersing process. The material is pumped into the barrel, together with the grinding medium, it is strongly stirred by the high-speed rotating grinding disc, and it is thrown along the disc to the wall of the cylinder and back again. The slurry flow reciprocates between the discs so that the solid material is gradually evenly dispersed in the liquid material. middle. The method of unloading varies with the viscosity of the material. Generally, the suspension can be used to flow out through a screen with slit holes, and the width of the holes is 1/2-1/3 of the grinding medium. The bead mill is a device that uses hard and wear-resistant zirconium beads, glass beads, etc. to rotate in a closed cavity to grind pigments.

Different types of ink used bead mills in different structures

Intaglio ink production generally uses pin rods (5-50 liters) or disc bead mills (10-100 liters).

Rotary offset printing inks generally use vertical rod type (5—130 liters) or horizontal disc type bead mills (60 to 500 liters), while the production of ultra-high viscosity sheet-fed inks often uses high energy density cone bead mills or three roll mills.

Inkjet inks (inks and pigment solvent-based inks) generally use high-energy-density pin-type (horizontal or vertical) bead mills and turbo-centrifugal nano-bead mills.

The new bead mill is the main grinding and dispersing equipment in the ink production process. The bead mill is a fully enclosed grinding equipment with automatic feeding, automatic temperature, and pressure control devices, and can carry out continuous production operations.

When the bead mill is running, the rotor agitates the meson (beads) to move at a high speed, and the high-speed running medium and the grinding cavity plays a role of dispersion through impact, friction, and shear. The vertical bead mill is a fully enclosed type, which can continuously grind and disperse granular and non-granular solid materials in liquid.

The structure and characteristics of the bead mill are:

①For grinding different varieties, the computer can input the pump flow rate, heating time, grinding chamber pressure, material temperature, and other technical data in advance according to the characteristics of the variety, and then the computer can automatically control it according to the input program.

②The annular groove on the stator can meet the different requirements of the product, and the high-precision special isolation groove can be used for the special viscosity.

③The temperature, pressure, feed pump flow rate of the rotor and stator are automatically displayed, and there are protection devices such as temperature and pressure.

④The grinding efficiency and dispersion degree can be obtained by adjusting the flow rate of the feed pump and the filling amount of the beads.

⑤Due to the use of special and latest technical materials, the grinding area and the isolation area are particularly wear-resistant, and will not affect the hue of the material.

⑥Bead mills usually have safety self-locking and alarm devices, and some faults can be automatically eliminated.

FRANLI as a manufacturer with more than 20 years of experience in the production and development of bead mills, our bead mills are high-efficiency wet grinding equipment, which has been used in paints, inks, pigments, paper coatings, ceramic glazes, Magnetic materials, plastic fillers, functional materials, and refractory gold mines and other industries.

All bead mills were originally developed and designed with inspiration from ball mills. A Bead mill, also known as a sand mill, is one of the best machines for wet ultrafine grinding equipment. It is characterized by the high processing efficiency of materials and wide practicability of materials. In general, bead mills are divided into horizontal bead mills and vertical bead mills, and the bead mills produced by FRANLI have higher performance.

Working principle of bead mill

The bead mill is a horizontal wet continuous production grinding and dispersing machine. The pre-stirred raw materials are sent into the grinding tank of the main machine, and the grinding tank is filled with an appropriate amount of grinding medium. The high-speed rotation of the dispersing blade gives the grinding medium enough kinetic energy to collide with the dispersed material particles to generate shearing and crushing force and extrusion. Press the crushing force to achieve the effect of dispersion, and then through a special separation device, the dispersed material and the grinding media are separated and discharged.

Development of bead mill

According to the development of the bead mill, it can be divided into five stages: vertical stirring mill, vertical disc bead mill, vertical pin bead mill, horizontal disc bead mill, and horizontal pin circulation bead mill.

The grinding process of bead mill

There is four main grinding process flow of bead mill, namely continuous grinding process, series grinding process, combined cycle grinding process, and single barrel cycle grinding process. The premise of the single barrel circulating grinding process is that the number of cycles is greater than 5, and the circulating barrel is equipped with a stirrer to ensure that the materials are fully mixed and avoid dead spots in the circulating barrel. The process is simple in operation and low in equipment investment and is generally used for the grinding of ceramic raw materials, such as silicon carbide, silicon nitride, boron carbide, etc.

Application of bead mill

◆ Bead mill for Ceramic ink

Ceramic ink is the core of ceramic inkjet printing technology. Its composition and performance are adjusted to meet the decorative effect and the working principle of the printer, and at the same time, it needs to meet the properties of stable physical and chemical properties and storage stability.

During the grinding process of ceramic ink, the material particles are crushed to a certain particle size by the sheer force and extrusion force between the grinding media to achieve the effect of dispersion. The stirring shaft of the bead mill rotates the material and the grinding medium to avoid the dead angle of grinding so that the material can be mixed more evenly.

◆ Bead mill for Titanium dioxide

Sand grinding is a key process in the crushing of primary titanium dioxide products in titanium dioxide enterprises. Only after the crushing process can the primary products of titanium dioxide be located in a certain particle size range, to carry out inorganic and organic coating treatment, reflecting its good pigment performance. To achieve the best sanding effect of the bead mill, it is necessary to adjust the process parameters according to the specific material conditions. The process parameters mainly include sand grinding speed, feeding speed, the particle size of zirconium beads, medium filling rate, and feeding concentration. Whiteness and water dispersibility are the key performance indicators of titanium dioxide pigments. Therefore, it is of great significance to study the effect of different particle sizes of slurry on its whiteness and water dispersibility.

◆ Bead mill for Painting

The bead mill used in the coating industry can be traced back to the 1970s. The vertical closed bead mill was introduced in China. The domestic model was successfully developed in the 1980s, and then a series of products were gradually formed. It was a breakthrough for the paint industry at the time. At the same time, it was widely used in paint enterprises and became the main equipment for grinding and dispersing in the paint industry at that time.

Recently, with the gradual expansion of the application of bead mills, the technical improvement of equipment has gradually increased, and the application of secondary energy-efficient energy-saving motors and frequency conversion technology in bead mills has been vigorously promoted, and PLC automatic control systems have been applied to the print production process. It greatly improves production efficiency, reduces energy consumption, saves labor costs, and reduces pollutant emissions, providing a new development opportunity for Chinese paint companies to go global. Since 1952, it has been widely used in the pigment and paint industry. About 70% to 80% of the paint products in China are completed by the bead mill, and later entered the field of pesticide processing.

◆ Bead mill for Ink

Dispersion grinding is an important part of the coating and ink production process. In the article “Application of Bead Mill in Dispersion and Grinding of Solvent and Water-based Ink”, Liu Caosheng et al. studied the application of bead mill in the dispersion and grinding of solvent and water-based ink. It mainly tests the effects of different stirring shaft speeds of the same type of bead mill, different grinding media (specific gravity, diameter, etc.), different cooling water temperatures, and different grinding methods (pass grinding and cyclic grinding) on ​​the grinding effect, as well as different types of bead mills. The grinding effect of the machine. It was found in the experiment that the M5 nano-bead mill was used for one-pass grinding, the linear speed of the grinding rotor was 18m/s, the time was set to 5h, the grinding medium was tungsten carbide, and the cooling water temperature was 10 ℃, which was solvent and water-based ink. Optimum conditions for dispersive grinding.

◆ Production of pesticides and suspending agents

Horizontal bead mills are widely used at home and abroad to produce pesticide suspending agent products; closed horizontal bead mills can nearly double the capacity of vertical bead mills, with low driving power and low energy consumption, and are more favored by users.

In the processing of suspending agent, the bead mill is the most important equipment in the dispersing process, and its main function is to disperse the solid particles of pesticides in the liquid medium (water). The general sanding function consists of three stages:

(1) Wetting, that is, the gas adsorbed on the surface of the pesticide solid particles is replaced by the liquid.

(2) Grinding, grinding large particles into small particles, and at the same time crushing the agglomerated particles into original particles by mechanical force.

(3) Dispersion, moving the wetted original particles into the liquid medium (suspended in the liquid) to produce lasting particle separation.

Practice and experience show that it usually takes 2~3 times of grinding, and the average particle size of the material can reach 2~3μm. The specific operation method is to use multiple bead mills in series. The particle size of the grinding media used in the barrel of each bead mill can be the same or different; Coarse to fine.

◆ Wet crushing of lead zirconate titanate

Introduced the equipment structure of a new type of bead mill and the working principle of the bead mill pulverization method in the article “The application of the bead mill method in the wet grinding of lead zirconate titanate”. The bead mill pulverization method was applied to the wet pulverization of lead zirconate titanate powder, and the ultrafine powder with the average particle size d50 of less than 0.45μm was obtained. The industrial production test of ultrafine pulverization of lead zirconate titanate powder proves that the bead mill pulverization method can be applied to the ultrafine pulverization process of the ceramic material industry.

In addition, bead mills have many applications in electronic ceramic slurry, new energy material processing, mineral powder, and other fields.