Calcined clay

Calcined clays have a unique structure which creates the highest levels of optical coverage, opacity and printability
Paper and board

A thermally engineered pigment designed for high light scattering performance. Commonly used as a cost-effective replacement for TiO2 in many applications

Imerys calcined clays are structured clays that are formed by treating select hydrous clay at high temperatures to form agglomerates that have a controlled pore structure that maximises light scattering. Calcined clay is generally used as a cost-effective opacifier and high light scatter pigment that provides excellent fibre coverage and bulk to the coating layer. It has been successfully used for several decades as a TiO2 extender.

Filling applications

In filling applications, our calcined clays improve:

  • Print appearance
  • Strikethrough
  • Brightness
  • Opacity

Coating pigment

Used as a coating pigment, Imerys calcined clays improve:

  • Coverage
  • Absorbency
  • Print properties


  • Specialty papers
  • Coated mechanical and coated wood-free
  • Coated carton board
  • White top and mottled linerboard
  • Uncoated freesheet

Imerys calcined clay ranges

  • Alphatex™
    Alphatex is a high brightness, calcined clay used for coating and filling applications in paper and board where high brightness and opacity are required. It is made via a precisely controlled thermal process using a select kaolin feed. The resulting product has a controlled pore structure that maximizes light scattering.
  • Therma-Print™
    Therma-Print™ is a calcined clay, designed to provide the right coating and surface structure for thermal transfer and thermally activated coated printing grades. Therma-Print improves coverage, absorbency and print properties.

Slurry and dry bulk form

Our calcined clays are available in slurry or dry bulk form that readily mixes in water to form a stable slurry. It is added along with other mineral coating formulation ingredients.

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