With the rapid development of the industry, especially the use of raw materials of higher and higher grades, for example, nanomaterials are gradually promoted to use, in terms of mixing efficiency, effect and quality requirements for mixing are also higher and higher.
Broadly speaking, nanomaterials are materials that have at least one dimension at the nanoscale (1-100nm) in three dimensions or that are composed of them as basic units. Nanomaterials, also known as ultramicrogranular materials, are composed of nanoparticles. Nanoparticles, also known as ultrafine particles, are in the transition region between the atom cluster and the macroscopic object. From the perspective of micro and macro, such a system is neither typical micro system nor typical macroscopic system, but a typical human mesoscopic system.
In brief, nanomaterials have the following characteristics:
Surface and interface effects; Small size effect; Quantum size effect; Macroscopic quantum tunneling.
Nanometer powders are very prone to "agglomeration" for the following reasons. The agglomeration of nanometer powder refers to the phenomenon that the primary nanometer powder particles connect with each other to form larger particle agglomeration during the process of preparation, separation, treatment and storage.
1) In the process of nanalization of materials, a large amount of positive or negative charges are accumulated on the surface of new nanoparticles. These charged particles are extremely unstable. In order to become stable, they attract each other and reunite the particles.
2) In the process of nanalization, a large amount of mechanical energy or heat energy is absorbed, so that the surface of the newly formed nanoparticles has a relatively high surface energy. In order to reduce the surface energy, particles often reach a stable state through mutual aggregation, thus causing particle aggregation.
3) When materials are nano-sized to a certain size, the distance between particles is very short, and the van der Waals force between particles is far greater than the gravity of particles themselves, so particles tend to attract each other and reunite.
4) Due to the hydrogen bond on the surface of the nanoparticles, the adsorption wet bridge and other chemical bonds, the particles are also prone to adhesion and aggregation.
Used for power type lithium ion batteries as "Submicron or nanometer anode materials such as lithium iron phosphate or anode carbon”, when mixing, it encounters “Submicron or nanometer scale, which easily causes “mass flocculation”.The following solutions are proposed to solve the problems caused by the phenomenon of "mass flocculation", such as the difficulty in dispersing evenly, the difficulty in mixing evenly or the long time of stirring.
Selection of destructive stirring equipment:
Planetary dispersion grinding vacuum mixer; Grinding and dispersing (vacuum) mixer.
Non-destructive stirring equipment selection:
Planetary dispersion emulsified vacuum mixer; Planetary dispersion vacuum mixer (dual planetary power mixer); Planetary dispersion static vacuum mixer; Ultrasonic dispersion + mechanical agitation/dispersion/emulsification.
II. The "planetary dispersion emulsifying vacuum mixer" is recommended.
"High shear emulsification" has the best function of "high speed mixing, dispersion, rapid refining, dissolution, homogenization and emulsification" for nanoscale materials due to its unique working principle. Widely used, mature technology.
1. Principle: the two serrated dispersion disks installed on the high-speed dispersion axis (the same as the principle of the traditional planetary power mixer) and the emulsifying head on the high-speed emulsifying axis both make revolution and rotate; At the same time, combining the design of low clearance of double agitator, no dead Angle, strong kneading interference motion of low-speed agitator and up and down/left and right circulation motion, high speed shear dispersion of dispersion plate and emulsifying homogenization of emulsifying head, ensure the full dispersion, homogenization and mixing of materials.
2. The essence of this machine is "non-destructive stirring", which can well protect the stirred materials from being damaged.
3, Prominent advantages: good combination of the "planetary low speed impeller, low clearance, strong kneading movement and interference and control/up and down cycle movement", "increase the linear velocity of dispersed after 23 m/s , high shear disc having good effect of “break up", and "linear speed or high shear emulsification of 15 m/s" , respectively play its role, make the material (especially the nanoscale materials) to reach a new level: high efficiency, uniform and high quality.
4. Basic structure:
One disperser shaft
One upper disc, and one lower disc
One emulsifier shaft
One high shear emulsifying agitator
Two mixing shaft
Two screw spiral agitators
One scraper shaft
One set flexible Teflon Plastic scraper
5, interchangeability: if the user wants to change to "double planetary mixer", just replace the "emulsifying part" with "high-speed dispersion part", which has a strong interchangeability and practicability.
6. Conditions of use:
6-1. The "RMRZH planetary dispersive emulsifying vacuum mixer" cannot be directly used for gluing (oil system: PVDF+NMP), that is, an independent gluing machine must be used to stir and mix "oil binder PVDF+NMP" after it is finished, and then it can be used for "homogenization (oil binder + positive or negative material)".
6-2. The "RMRZH planetary dispersion emulsifying vacuum mixer" can be directly used to homogenize "water-based adhesive + anode material or cathode material".
7、Very idea effect: high efficiency, good mixing
III. Planetary vacuum disperser and mixer (double planetary mixer) structure
Two disperser shaft
one upper and one lower disc for each disperser shaft
Two mixer shaft
Two sets spiral twist agitators (one for each mixer shaft)
One set flexible Teflon plastic scraper knife
Iv. Unique features of blender:
1. Structure: new planetary gear box, low noise, high stability, maintenance-free, long service life.
2. The section of "spiral twist type stirring slurry" is "pentagonal". The design of "low clearance and 18 degree engagement Angle" is adopted between the two stirring slurry.
3. The spiral twist mixing slurry is designed in strict accordance with the scientific spiral principle, cast and formed, and the spiral surface is processed and formed by the CNC machining center.
4, the mechanical seal "dynamic and static ring" material selection is reasonable and reasonable selection of lubricating oil, can greatly extend the service life; Unique mechanical seal seat design, better prevent grease leakage splash/dust/lubrication reliable.
4. Each transmission shaft, especially the high-speed shaft, has been scientifically calculated (anti-torsion, shear and resonance frequency), which conforms to the rigid shaft design, avoiding distortion and resonance phenomenon of high-speed rotation.
6, Can output high line speed ≥20m/s of dispersed shear and emulsification functions.
7. The new "planetary gear box" is a "fully sealed structure" with multiple leak-proof structures to prevent external materials from entering the corrosion high-speed synchronous belt and gear lubrication. The external surface can be washed with pressure tap water; Although the structure is complex, it is easy to disassemble and facilitate the replacement of high-speed synchronous belt.
8. High degree of automation, which is conducive to human operation and high safety: all kinds of agitator barrel emplacement guarantee devices (mechanical guide rail/limit pad and upper kettle cover positioning stop mouth, combined with electric sensors), hydraulic locking agitator barrel to prevent interposition, as well as rich and perfect man-machine interface operation and so on.
9. High stability and mixing: low failure rate, long-term vacuum stability, good mixing effect and high efficiency.
V. simulation demonstration of planetary dispersion and agitation process:
1. Two-axis planetary low-speed part (spiral twist agitator) stirring process:
1-1-1. Design simulation of "low clearance of agitator with pentagon section and kneading extrusion with 18°" :
1-1-2. Motion trajectory simulation of "planetary stirring outer endpoint" :
1-2、Simulation of the one-week movement trajectory of the helix of the outer section of the screw twist agitator：
1-3、Movement trajectory simulation of pentagonal section of spiral twist agitator：
2、The composition of "Rumi technology planetary dispersion emulsified vacuum mixer series" is recommended as follows：
Above picture for mold temperature machine for heating and cooling, and tilting for discharging material, for double planetary mixer