Harborlite® and Celite® filter aids for biofuel

Our Harborlite and Celite filter aid ranges are solutions of choice for reducing impurities in biofuel production.

Man fuels the car with biodisel

Harborlite - A perlite solution for biofuel purification

Our Harborlite range is a formulation of naturally occurring perlite that can reduce impurities in biofuel production.

Harborlite perlite is an expanded perlite particle, precisely milled to desired particle-size distribution to make various grades, able to filter a wide array of liquids. The unique structure of perlite makes for a very light weight with 30 percent to 50 percent less bulk density compared to other filter aids, meaning users typically require 30 percent to 50 percent less additive. The high void volume and porosity of perlite form a thick, permeable filter cake improving permeability and flux rates

Imerys owns and operates numerous perlite plants throughout the world, including sizable ore deposits in the United States. We are one of the few perlite producers able to control the entire quality chain - from the mine to finished product. Most of our perlite products are standardized - guaranteeing our customers consistency of service. Our network of interconnected plants minimizes transport distances - with much shorter lead times as a result. This type of geographic coverage reflects our commitment to operating as close to our customers as possible to reduce transportation challenges.


  • Security of supply
  • Low bulk density
  • High void volume and porosity
  • Relatively inert in most solvents
  • Neutral pH
  • Hydrophilic 

Harborlite SEM image

Celite - A diatomite filter aid for biofuel filtration

Celite filter aids have been used in edible oil and animal fat filtration for decades. While biofuel filtration is similar, it requires a higher performance filter aid to maximize profits with this higher value end-product, biofuel.

Celite meets this need with filter aids specifically developed for biofuel, which enable faster filtration and increased oil recovery. Celite filter aids can be used at all stages of the biofuel filtration process to maximize product yield and improve quality.

A technique used since the early 1900s, filter aid filtration is widely believed to be the most robust technology for difficult filtrations, such as biofuel, where high solids loading combined with viscous and variable feedstocks are the standard. It continues to be a robust method of separation technology for compressible solids (e.g., gums and waxes), especially when feedstock solids loading is greater than 1%. The advantages include high solids capacity, low cost and ease of scale-up.


  • Versatility
  • High clarity results
  • High throughput
  • Simple scale-up from bench-scale to production-scale

Diatomite filter cake


If you'd like to discuss how we can help you increase filtration capacity, reduce your filtration costs, or improve your product quality further, contact your local Imerys representative or your local appointed distributor.


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