Introduction to Minerals for Solid/Liquid Separation

How Diatomaceous Earth and Perlite Are Used for Liquid Filtration

solid/liquid separation

Like many events this year, the World Filtration Conference is postponed until further notice. This event brings together professionals in a variety of industries to educate about best practices and introduce new filtration options. Dicalite Management Group‘s mineral filter aids were going to be featured in the Introduction to Solid/Liquid Separation, a short course about filtration from an industrial application perspective. While the course postponed for the time being, today, we’re going to give you a preview and introduce your mineral options for solid/liquid separation, also known as filtration.

Filter Considerations

Filtration is the process of separating liquids and solids. There are chemical and mechanical filter media options. Filtering is not a one-size-fits-all process, and there are many things to consider. You can compare your solid/liquid separation options by considering:

  • Flow rate
  • Desired clarity of the liquid
  • Uniformity
  • Cost of the filtration method
  • Ease of use

Solid/Liquid Filtration Using a Filter Aid

Mineral filter aid filtration (depth filtration) is mechanical, not chemical in nature. This filtration method requires the liquid to flow through a porous filter media and depositing the solids on the media. A filter aid is a finely divided material which when added to the liquor to be filtered helps control flow and solids removal. Irregularly shaped particles interlace and overlay in a fashion that leaves microscopic voids or open spaces. The size of these openings is so minute that the unwanted solids are strained from the liquid.

The use of a filter cake requires a septum. The septum, usually screen or cloth, serves principally as a support for the cake. The filter aid forms a porous cake on a septum, stopping solids while preventing them from blinding the septum. This mechanical process can provide brilliant clarity and eliminates potentially dangerous contaminants when the proper media is used.

Diatomaceous Earth and perlite are two effective filtration media options. They are available in a variety of grades to meet the solids removal requirement of any application.

Diatomaceous Earth for Solid/Liquid Separation

Diatomaceous Earth is a form of silica that has been used as a filter aid for nearly a century. It is composed of the diatoms, skeletons of microscopic plants, deposited on the bottom of oceans and lakes after and during the Miocene Age from 100,000 to 15,000,000 years ago. To see why diatomaceous earth is a great filtration media and filter aid, you’d have to view it through a microscope. You would discover diatoms have a wide variety of shapes and a honeycomb-like structure that capture solids.

Benefits of Diatomaceous Earth for Filtration

  • High Porosity. The pores within and between the cell walls are so small, they trap bacteria, clay particles, some viruses, and other suspended solids from liquids, leaving liquids cleaner and with drastically reduced solids and contaminant levels.
  • High Flow Rate. Diatomaceous earth filter cakes extend the flow rate of the material being filtered and prevents clogging.
  • Longer Filter Cycles. The high solids holding capacity of diatomaceous earth allows for much longer filter cycles (allowing more solids to be removed) than what would be possible with other filtration methods.


Dicalite Diatomaceous Earth (DE) Filter Aids are approved by several government agencies as a food and beverage processing aid. Also, Dicalite diatomaceous earth is NSF Part 61 certified and can be used in the production of potable water by municipalities.

Perlite for Solid/Liquid Separation

Perlite is an amorphous mineral consisting of fused sodium potassium aluminum silicate. In its natural state, it’s a dense, glassy rock formed by volcanic rock. When crushed and organic acids at both low and high and treated under proper conditions, perlite pops like popcorn, expanding up to 20 times its original volume.

Benefits of Perlite for Filtration

  • Easy Application: Experience in a variety of applications has shown users can easily switch their current filtration media to a perlite filter aid economically and without sacrificing performance. It can be used with either pressure or vacuum filtration equipment.
  • Inert State: Perlite is naturally inert, so no tastes, colors, or odors are transferred to the filtered product. This is especially important for food applications.
  • Insoluble: Perlite filters are virtually insoluble in mineral and organic acids at all temperatures. Solubility in strong alkaline solutions varies, depending on temperature and contact time.
  • Lower Weight, Same Volume: Perlite filter aids can weigh as much as 50% less than the other types of filter media. This makes it easier and safer to use.
  • Impressive Density. Perlite filter aid grades provide the user with a density advantage from 20 to 50% over other types of filter aids.
  • Anti-Caking: Perlite filter aids are also revered for the end of the filtration process; the filter cakes remain porous and do not compact.
  • Cost Savings: When compared to other filtration media, like Diatomaceous Earth, perlite offers comparable savings in filter aid usage, especially on rotary vacuum precoat filters.


There are many ways perlite is used for solid/liquid filtration including:

Food and Beverage

  • Juices
  • Beer
  • Wine
  • Sweeteners
  • Vegetable oils
  • Wastewater treatment


  • Enzymes
  • Antibiotics
  • Epsom Salt


  • Water treatment
  • Sizings
  • Oil and solvent recovery
  • Greases


  • Inorganic & organic chemicals
  • Resins
  • Polymers
  • Brine
  • Adhesives
  • Fertilizers
  • Waste disposal

Paint and Coatings

  • Waxes
  • Oils
  • Varnish
  • Gyms
  • Shellac
  • Wastewater treatment


  • Stormwater filtration
  • Ecology embankments
  • Media filter drains
  • Wastewater treatment

Dicalite Management Group is Here for Your Solid/Liquid Filtration Needs.

The mineral experts at Dicalite Management Group know the ins and outs of using diatomaceous earth and perlite for filtration. We know you’ll love it too, so we’d like to send you a free sample. Our customer service representatives located at our plants are standing by, and our technical experts are anticipating your call. Call us today at 866-728-3303 for your free sample and to see for yourself what makes Dicalite Management Group a customer-first industrial minerals company.

If you’d like to learn more about using minerals for filtration, download our free e-book A World of Filtration Experience today.

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Our blog offers insight and information about new and exciting uses for perlite, diatomaceous earth, and vermiculite deriving from years of research and application. From passive fire resistance to mineral depth filtration, by subscribing to our mailing list, you will receive the latest information surrounding the Dicalite, Dicaperl, and Specialty Vermiculite brands and products.

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