Know your industrial mixing processes so you can select the right mixer for your business.
Before you decide on a new piece of equipment for your facility, it’s important to understand how different mixing processes work.
Getting a solid understanding of the difference between mixing, emulsifying, dispersing and blending will ensure you end up with a mixer that will boost efficiency and improve the consistency of your product.
What are the different types of mixing processes?
Successful and consistent fluid mixing can be a complex process, with different types of mixing equipment required to get the optimum result. Every application is different, and often a combination of processes will be needed to ensure the final product passes quality control.
These processes can include shear mixing, suspension mixing, blending, dispersion, agitation and more.
Choosing the optimum mixing equipment, and ensuring it integrates properly with your wider manufacturing or processing equipment, will ensure you avoid issues with unmixed products or ingredients that are not fully emulsified.
1. Blending miscible liquids
Miscibility simply means that two or more liquids will completely incorporate into each other, forming a relatively stable mixture. Miscible liquids are some of the easiest substances to blend, forming a cohesive mix that is resistant to separation.
A liquid is considered to be miscible if it forms a homogeneous, uniform solution with the same molecular structure throughout the mixture. For example, alcohol and water form a miscible liquid, blending easily when introduced to each other.
For this reason, miscible liquids often don’t need an aggressive mixing technique such as high shear mixing. Instead, they rely on the natural flow of the liquids inside the vessel or tank which is often enough to mix the liquids successfully.
If your product uses miscible liquids, choose an industrial mixer with a light agitation such as a portable clamp-on agitator mixer or a combined tank and mixer unit.
2. Soluble Solid-Liquid Dissolution
Soluble solids include products such as sugar which, when mixed with liquid, results in a soluble solid/liquid dissolution. Due to one material being in a solid state and one in a liquid, this type of mixing can take longer than blending liquids alone. However, recent advances in powder into liquid mixing technology such as the Mixquip Series 620 Powder Liquid Mixer have resolved these issues.
Because soluble solids are readily dissolved in liquid, they don’t require aggressive agitation. The level of agitation will depend on the solubility of the solid, so more robust solids or those with a larger particle size may require a stronger agitation.
Creating a solution from a powder or granulated product relies on flow or forced powder integration. A flow driven process with low to moderate agitation requires an adequate time to dissolve the product, whilst the Series 620 Powder Liquid Mixer will give the best result.
3. Chemical Reaction
Chemical reactions can be instigated by adding heat or pressure or by blending reactive ingredients that cause their own temperature and pressure changes. Due to the unstable nature of this process, it can be difficult to see consistent and predictable results at scale, making smaller batch processing a more reliable course of action.
Flow is again the primary action for this type of mixing process, but to avoid inconsistencies due to dead zones or channels in the vessel or tank, the addition of moderate agitation should be considered. This will ensure that consistent blending and subsequent reactions happen throughout the entirety of the product.
4. Insoluble Material Suspension into Liquids
Products such as paint and shampoo are created by suspending insoluble pigments and dyes within a solvent. Although initially quite stable, suspensions are inclined to settle over time, even after employing an ideal mixing technique. Because of this tendency, these types of products often require instructions to stir, mix or shake before use.
At the mixing stage, because products like pigments are often insoluble with other components of the product, a combination of flow and shear-driven mixing is required to get the desired suspension. The high shear of Mixquip Series 600 and Series 620 mixers ensures a homogeneous solution instantly.
This mixing process covers a range of different product types so individual advice is necessary, but suspending insoluble materials often requires moderate to aggressive agitation with the addition of high shear action.
5. Dispersing solids into liquids
Successful dispersion relies on high shear forces close to the blades of the mixer. However, as the agitator speed reduces, solids can accumulate and settle near the bottom of the tank. As with suspensions above, advice to mix, shake or stir the product before use is often necessary, for example in a bottled green smoothie.
Occasionally the end product will be improved by the solids settling, in which case a slower agitator speed can be used to get this effect. Ultimately, this mixing process needs to be uniquely tailored to each product, but in the majority of cases an aggressive, high-shear dispersion will create the desired result.
6. Emulsifying immiscible liquids
One of the most common industrial processes is emulsification, a process that makes immiscible liquids into a miscible product, for example, a fat such as olive oil and a water-based liquid such as vinegar.
Common emulsifiers include natural proteins such as lecithin found in egg yolks and casein in butter. These common ingredients have many useful applications in the food industry including the production of mayonnaise and ice cream.
Despite the chemical emulsification happening through the use of natural proteins, successful mixing will often require a high-shear impeller process to ensure uniform consistency.
We can help you choose the right mixer for your process
For almost 50 years, Mixquip has specialised in manufacturing quality mixing systems for processing and manufacturing worldwide. With our long history in the industry, we’ve had experience with a wide range of applications, and our sales and engineering team truly understands your challenges.
Get in touch with the friendly team at Mixquip for engineering advice and support on our range of commercial and industrial mixing equipment.