High Viscosity Material Industrial Mixers Guide

Challenges of High-Viscosity Mixing

When mixing high-viscosity materials, you can’t just look at the viscosity number. This is because the material can thicken or thin during the mixing process. For example, it might suddenly thicken after adding powder, or thin out after prolonged mixing. Therefore, when selecting equipment, you need to consider how the material changes throughout the entire batch.

1. Hard to turn over

The biggest challenge with high-viscosity materials is that they are difficult to turn over. Low-viscosity liquids form vortices as soon as they are stirred, whereas high-viscosity materials tend to stack in layers. Ordinary mixing paddles only rotate in localized areas, making it difficult to thoroughly mix the upper and lower layers. A good mixer must be able to bring the bottom layer to the top and push the top layer down.

2.Easy to heat

Another issue is heat generation. Friction generates heat, and heat-sensitive materials are prone to degradation, so jacket temperature control is crucial.

Common Industrial Mixing Equipment for high viscosity material

1.Planetary Mixers

The blades rotate both on their own axes and in a circular motion, continuously incorporating new material. This makes it suitable for very thick, nearly non-flowing pastes, such as adhesives and battery slurries. It features wall-scraping blades to prevent material from sticking to the vessel walls.

2.Multi-Shaft Disperser Mixers

A low-speed anchor-type agitator handles overall circulation, while a high-speed dispersing disc breaks up agglomerates. This system is suitable for mixing powders into high-viscosity liquids. It is highly efficient but features a complex structure and higher costs.

3.High-Shear Mixers

This mixer generates strong shear forces through high-speed rotors and stators, making it suitable for breaking up clumps, refining particles, and emulsification. It excels at localized shearing but has limited overall circulation capacity, so it is typically used in conjunction with low-speed agitation or wall scrapers. It is suitable for adding powders to high-viscosity matrices and producing fine pastes. Care must be taken to manage heat generated by shearing; temperature control is essential for heat-sensitive materials.

Key Considerations for Selection

1.Charging Capacity:

High-viscosity materials should generally fill only 40% to 70% of the vessel’s capacity. Too much material will prevent proper agitation, while too little will prevent contact with the impellers.

2.Discharge:

High-viscosity materials will not flow out on their own; they require tilting, screw discharge, or pressurization.

3.Scale-up:

Scaling up from pilot-scale testing to production is not simply a matter of scaling up proportionally; it is best to conduct pilot-scale testing using the actual material.

In summary

first observe the material’s actual behavior, then review the equipment specifications. Viscosity is merely the starting point; rheology, temperature, discharge, and scale-up are the key factors.