Mixing Tips

Gums & Thickeners – How to Avoid Agglomerates

Suppliers of gums and thickening agents will advise you to sprinkle the powder slowly on the liquid surface to reduce the formation of lumps and fisheyes, because the washing action of conventional agitators cannot readily break these down, resulting in inconsistent product quality and poor yield.

With a Silverson High Shear mixer the opposite approach should be taken; the powder should be added to the liquid all at once, in a controlled manner but as quickly as possible. The mixing/shearing action of the rotor/stator workhead rapidly disperses and hydrates the powder before the viscosity starts to increase, ensuring an agglomerate-free solution is achieved with maximised yield and consistent, repeatable results.

Blending Liquids of High and Low Viscosity

When blending liquids of high and low viscosity, start with the low viscosity liquid and add the higher. This is more energy efficient, because the mixer doesn’t need to be sized to process the highest viscosity. Where colouring or dye is to be added, leave this until last as this acts as a visual indicator that a consistent mix has been achieved.

Optimal Particle Size Reduction

When dispersing powders where a degree of particle size reduction is required, best results can be obtained by adding the powder to the smallest possible volume of liquid. This focuses the mixer’s energy on dispersing and milling the powder rather than moving the full volume of the batch, and the concentration of powder provides attrition which accelerates the reduction of particle size. Once the required particle size is achieved the remaining liquid can be rapidly blended into the mix using the Silverson mixer.

Efficient Emulsion Preparation

When forming an emulsion, ensure that the dispersed phase is added to the continuous phase correctly. At laboratory scale, this is less critical, but when larger volumes are involved, it is essential to get this right, a common problem when scaling up. Silverson In-Line mixers are ideal for the preparation of emulsions, and adding the dispersed phase just prior to the In-Line mixer will ensure an instant emulsion.

Need to Increase Production, but Limited on Space and Budget?

Adding a Silverson In-Line mixer to your existing process can reduce mixing times by up to 90 percent, allowing you to substantially increase productivity without the need for additional vessels or other capital equipment.

Maximise the Efficiency of Your Milling Process

Where conventional milling equipment is being used, pre-milling the product with a Silverson mixer will create a uniform premix that will pass through the conventional mill at a much faster rate, because media mills work best when fed with a product of a consistent and low particle size. In many cases the Silverson mixer can dispense with the need for conventional milling altogether. Silverson offers a range of mixers including single and multistage In-Lines and the Multishear Mill, designed for processing even the hardest materials such as pigments, dyestuffs, filter cake, titanium dioxide, etc.

Improve the Performance of Your High-Pressure Homogeniser

High-pressure homogenisers are costly to buy and operate; they are maintenance intensive devices and have a relatively low throughput. Processing product through a Silverson In-Line mixer prior to the homogeniser produces a low globular size, uniform premix, which will pass through the homogeniser at a much faster rate, normally in a single pass. In many cases, the low globule size produced by the Silverson mixer can eliminate the need for a homogeniser altogether.

Trouble Scaling Up from the Laboratory to Full Production?

Do you find it difficult to replicate the results from the pilot plant? The key to successful scale-up is to use equipment that matches as closely as possible the production plant. Many suppliers of laboratory mixers are specialists in small units, but do not produce large scale equipment. Silverson’s laboratory mixers are scale models of their production counterparts, and will give identical end results, enabling you to replicate in the laboratory, the performance of every mixer in Silverson’s product line with accurate and repeatable results.

Looking to Eliminate Aeration from Your Mixing Process?

Silverson In-Line mixers offer aeration-free operation. The mixer, pipework and vessel form a closed system, and the flooded suction provided by the self-pumping In-Line mixer cannot introduce air into the product. This makes it ideal for the processing of aeration sensitive products such as shampoos and detergents.

Dispersing Powders without the Need to Premix

Unlike eductor funnels and other conventional powder/liquid mixing systems, when using a Silverson Flashblend, ingredients don’t need to be premixed before addition to the feed hopper. For example, suppliers of gums and thickeners sometimes advise premixing them with other powders to reduce the formation of agglomerates in conventional processes. This is not necessary with Silverson powder/liquid mixing systems, because the high shear rapidly incorporates the powder into the liquid and shears any agglomerates down, ensuring complete dispersion and hydration of the powder and maximised yield.

Accelerate Your Solubilisation Process with a Silverson In-Line Mixer

If you are solubilising rubbers or polymers into solvents, oils or asphalts, your in-tank agitator might incorporate the material efficiently, but the washing action of the agitator cannot reduce the solids in size so it takes a long time to completely solubilise the polymer. A Silverson mixer will accelerate the process as the liquid and solid materials are subjected to intense high shear as they pass through the workhead, reducing the particle size and so exposing an increasing surface area to the surrounding liquid. The combination of finely reduced particle size and vigorous mixing rapidly solubilises the polymer or rubber. Silverson offers a range of equipment to suit all batch sizes and types of polymer, including systems that can handle whole bales of material into the solvent, eliminating preliminary chopping and grinding stages.

Optimised Order of Ingredient Addition

A Silverson High Shear mixer can simultaneously carry out a range of mixing tasks – disintegrating, dissolving, emulsifying or homogenising, etc. – many products can be manufactured in a single step using a Silverson mixer. Where gums and thickening or stabilising agents are included in the formulation, add these last. This allows other powders in the formulation to be dispersed easily while viscosity is low, and prevents degradation of structured products when adding ingredients that may affect pH.

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