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Compressed to Reveal New Benefits – HDK® Pressed Grades

Powerful and highly efficient – HDK® was developed to deliver maximum performance. Whether in the pharmaceuticals, packaging, energy or construction industries, HDK® pyrogenic silica is a true multitalent, optimizing the performance, stability and handling of your solutions and formulations in every phase of production and processing. The impressive qualities of WACKER’s traditional HDK® grades are now joining forces with the powerful benefits of HDK® Pressed Grades.

Big Things Come in Little Packages

Things that might seem small – like HDK® from WACKER – often have an extraordinarily big impact.

18 grams of a typical pyrogenic silica are enough to cover an area the size of a soccer field.

18 grams – that’s roughly the weight of two €2 coins.

Particles As Global Players

Visible only with special microscopes, HDK® particles are true global players, preventing powders from clumping and improving the flow characteristics of liquids.

More about pyrogenic silicas

HDK® Pressed Grades – A Little Difference with Big Benefits

A mechanical compression process makes this jack-of-all-trades even smaller. But when it comes to their properties, HDK® Pressed Grades hold their own with other HDK® grades. In fact, what seems like a little difference at first glance delivers big benefits – both for your company and for the environment.

A Detailed Look at How HDK® Pressed Grades Can Benefit You

Twice the Density – Less Storage Space

After production, HDK® Pressed Grades are mechanically compressed 2.5-fold, from roughly 40 to 100 g/L tap density. This degree of compression means that a bag of HDK® Pressed Grades contains more than twice the amount of product, reducing the number of packages required – and saving valuable storage space.

Less Dust Means Less to Clean

HDK® Pressed Grades produce less dust during handling (emptying bags, etc.). That simplifies production workflows, with more product ending up where it’s really needed. Plus, less dust means less cleaning and can also reduce the need for workplace ventilation.

A Sustainable Concept That Saves Time and Valuable Resources

The high level of compaction cuts transport volumes in half, greatly reducing the high cost of shipping. That means every truck or ship can transport more product, which also reduces the resulting carbon footprint. Plus, HDK® Pressed Grades generate less waste, because more HDK® can fit in a given bag. And that saves packaging material, preserves resources and protects the environment.

Discover the Many Different Ways of Using HDK® Pressed Grades.


The thickening action and chemical robustness of HDK® Pressed Grades are the key advantages of their use in sulfuric acid gel batteries. In this variation of the lead-acid battery, the electrolyte consists of liquid sulfuric acid that has been thickened to a solid gel through the addition of silica. The resulting high level of viscosity prevents the electrolyte from leaking. Plus, because there is no need to refill the water, gel batteries require no maintenance. In this way, HDK® Pressed Grades play a critical role in long-term, reliable battery function.

Domestic Helpers

Pyrogenic silicas are indispensable for mechanically reinforcing silicone elastomers, where they lend HTV and LSR products the tensile strength they need in combination with good elasticity.

In applications like these, HDK® Pressed Grades offer even greater advantages, because they can reduce compounding times with only modest thickening.


HDK® Pressed Grades are an indispensable excipient in pharmaceuticals. As pyrogenic, colloidal silicon dioxide, pyrogenic silica reduces caking in powders, improves the flow properties of liquids and enhances the quality of tablet and capsule manufacturing processes, making pelletizing and tableting far more efficient. For liquid pharmaceuticals, HDK® ensures consistent performance from storage to application.

Want to Learn More about HDK® ?

Then visit our product portal, where you will discover more of the many potential applications of our ultrapure HDK® grades.

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