Technical knowledge
Home

Technical knowledge

The nanometer dispersible liquid (Ⅲ)

The nanometer dispersible liquid (Ⅲ)

  • April 8,2020.

The nanometer dispersible liquid

- promotes the exchange of ceramic ink-jet technology of traditional inorganic pigments


(Continued)


2 - Concept of interface modification technology


2.1 Chemical mechanical process

Previously, you can use the dispersing grinding equipment  such as three roller grinding, dispersing machine, bead mill, agitator mill, to disperse the material to micron or sub-micron level, but it is difficult to achieve nanoscale fineness!


The main reason is, once the particle of the material was mechanical dispersing and grinding into nanometer, the specific surface area of the powder has increased dramatically, Van der Waal's force effect and Brownian motion become obvious, the powder agglomerate together again easily, so no matter how to dispersing and grinding, the particle size still hard to reduced down!


In order to solve this problem, here we introduce a very effective method -  chemical mechanical process. The main concept of this process is shown as below, it will produce good interface modification agent, use the high speed agitated beads mill as the tool, to make the appropriate interface modification nano powder, to avoid the agglomerate of nano powder, keep dispersing and grinding, until the particle size achieve to the requirement.

Figure 3 - Development of Wet grinding mill


Figure 4 - Grinding mill principle


2.2 Use the agitator grinding mill as the reactor

The agitator grinding mill plays an important role in the chemical mechanical process.


This system adopts the wet dispersing and grinding. Since it is wet method, the temperature of the slurry will not rise rapidly as a result of grinding, so you can choose smaller grinding media, such as 0.05-0.3mm zirconia beads, then with the high linearity of the grinding machine (about 10 ~ 16m/s), to shorten the time required for dispersing, grinding and reaction.


Another advantage of this process is that all grinding parameters, such as the speed of the agitator, filling rate of the grinding media, flow rate, product temperature, can be adjusted to the optimal grinding conditions according to the needs, and can be scaled up to be used in formal mass production in the future.


During the chemical mechanical process (ref Figure 4 and Figure 5), we just need to add the surface modification agent into the powder slurry, then in accordance with the final grinding particle size requirement to set the power and specific energy consumption that the grinding mill required, use the circulation operation mode for dispersing, grinding and interface modification work. The power consumed will be accumulated automatically during the operation of the grinding machine, when it reached to the set energy ratio, the mill will stop automatically, so as to ensure the uniformity of grinding quality.

Figure 5Wet grinding of series process

Figure 6


From experience, when dispersing or grinding nano powder slurry without adding the appropriate surface modification agent, just only by the mechanical strength of the grinding mill, normally only reach to 300 ~ 800 nm, and then unable to reducing more. When the particle size is less than 300 nm, specific surface area of the powders rapid rise and the effects of the Van der Waal's Force increased, the powder now in a very unstable and easy to recondense state. Even if the aggregated powder is dispersed by the grinding beads, it is still very easy to condense back, unless the appropriate surface modification agent is added, then makes it possible to continue reducing the particle size downward.


(To be continued)

© Copyright: 2020 PUHLER (Guangdong)Smart Nano Technology Co.,Ltd. All Rights Reserved.

IPv6 network supported

top

Leave a message

Leave a message

    If you have questions or suggestions,please leave us a message,we will reply you as soon as we can!