Diatomaceous Earth and Perlite

Filtration using mineral additives provides flexibility and ease of processing.

Diatomaceous Earth

Diatomite, or diatomaceous earth, is the skeletal remains of single-celled algae, called diatoms, whose cellulose membrane has the capability of extracting silica from water. Over millennia, the skeletal remains of diatoms built up and formed huge diatomite deposits. The lightweight and porous rock obtained from the fossilization of diatoms is the raw material of our products. Following treatment, diatomite forms a highly porous white or pink powder, marketed under the trade name Clarcel®.


Perlite ore is a silica rock of volcanic origin that contains fine water droplets. It is expanded at high temperature, then crushed and graded, and constitutes our Randalite® and Randafil™ product ranges.

Filter Aids

Filtration using mineral additives provides flexibility and ease of processing. It is suitable for all types of liquids and impurities. Today it is the reference technology in many industrial sectors, such as:
• Agro-food and beverage industries: clarification after extraction, hydrolysis, pressing or fermentation of organic material of vegetable or plant origin
• Metallurgy: filtration of machining and roll fluids
• Chemicals: filtration of organic and inorganic chemical intermediates
• Pharmaceuticals: filtration of antibiotics and other active principles

Calgon Carbon’s European operations, known as Chemviron, offers a comprehensive range of filter aids used as processing aids during industrial processes. They are marketed under the brand names Clarcel® and Randalite® and cover a wide range of permeabilities.

The Clarcel® and Randalite® product ranges are suited to all types of precoat filters:
• Roughing filtration on rotary filters and filter presses,
• Fine filtration and polishing filtration on frame and candle filters.

The porosity imparted by our filter aids to the filter cakes helps extend the treatment cycles while ensuring optimum clarification.

Compliance with stringent specifications ensures the high performance of Clarcel® filter aid.
The permeability of our products is controlled in real time. Systematic checks are also performed on other characteristics:
pH, moisture, loss on ignition, etc.

Chemviron’s processing aids treated at high temperature feature a high degree of chemical inertness. Particular attention is paid to the purity of our products.
Extensively present in the food industry, Chemviron ensures full traceability of its products, from selection of the ore to the filter aid’s packaging.

Functional Filters:

Clarcel® and Randafil™ can be used as functional additives in many markets, such as paint, plastic or paper industry.

The outstanding properties of diatomite and perlite make them remarkable functional additives, over and above their role in filtration applications. They are graded and selected on the basis of their particle size and whiteness.

Their particle size ranges are particularly suited to both waterborne and solvent-based paint formulations.

These functional additives impart a matte look to the paint, extend its lifetime, and improve its application qualities.

Clarcel® and Randafil™ are also used in polyethylene film manufacture as antiblocking agents. They are also used to enhance the mechanical properties of certain polymers.

In the paper industry, they improve the printability of paper, and are also used as dispersing agents and opacifying agents.

The purity and high porosity of diatomite and perlite make them top-grade ingredients for the manufacture of cosmetics and dental impressions.
Chemviron offers a comprehensive range of functional mineral additives serving the following main markets:
• paint and coatings
• plastics industry
• pharmaceuticals and cosmetics
• paper manufacturers