Innovation - engineering - processes


Thermal processing of powders: introducing the Spirajoule, heating screw conveyor powered by electricity.

Whether it is calcination, volatiles removal, controlled atmospheres treatment, pyrolysis or torrefaction – thermal processing technologies are bringing a lot of opportunities to add value to the common and specialized materials.

Our technology is made for a wide range of treatment and it offers the possibility to be tailored exactly to your need. It is also powered exclusively by electricity, helping to carry the process without greenhouse gas emissions and standing up to the challenge of climate-friendly heating based on renewable energy sources.

Expertise in a variety of powder, granules & bulk solids treatment

Spirajoule technology was originally developed in 1999 for food ingredients treatment. From food ingredients, through forestry and crops residues, up to the various polymer treatment and minerals processing – since over 20 years we design our solutions around the specific need of the industry. We have worked with a variety of products using the temperatures between 100 to 850 degrees C and treating free-flowing granules, crystals, powders, pellets, sands, and seeds.

heat treatment by electricity

Simple and robust solution for controlled heat treatment

Innovative combination of hollow shaft screw conveyor and resistance heating

Our technology is based on hollow shaft screw conveyor that is mounted in the “u-shaped” auger reactor, also called a trough. The driving motors that are moving the screw are installed at the discharge or both ends of conveyor and rotate the screw blades. During the rotation, the flights of the screw are gently moving the free-flowing granular materials along the process reactor. The electricity is passing through the screw and heats the product at a precise temperature. The material exits the reaction chamber at the end of the process.

Both inventions, the screw conveyor, and resistance heating were used in the industry for a long time. The unique simplicity of combining both concepts allowed us to create a system that is reliable, low maintenance and efficient in the functions it performs.

The advantages of hollow shaft screw construction of Spirajoule are:

  • precise conveying of the bulk and powders
  • low risk of failure
  • gentle, dust-minimum transport
  • continuous processing
  • compact, space-saving design
  • robust, simple and safe

The advantages of resistance heating of Spirajoule are:

  • direct heat transfer (no shell, no double jacket)
  • high heat exchange coefficient
  • precise control over the treatment temperature
  • accurate adaptation of operating conditions
  • heating using fossil-free energy sources
example spirajoule heat treatment process

High temperature, electrical heating of powders and bulk products

Advanced treatment free of fossil-fuel heating

Following the increasing demand for fossil-free products thermal treatment, ETIA has developed a special range of applications dedicated to processing the powders in temperatures up to 850 degrees C. Such high temperature treatment of the powders is increasingly required at the market when the interest is in production of high added value materials.

Treatment of materials in controlled conditions triggers the chemical reactions in the product that would be otherwise unavailable, leading to the modifications of its structural, chemical and physical properties. It allows to engineer the products up to the specific market demand and add significant value to otherwise low quality materials.

The fundamentals of the system are based exclusively on electricity, which is increasingly often coming from renewable sources. Thermal solid processing is performed without the necessity of combusting the fossil fuels to produce the heat necessary for reaction. This often allows to avoid the unnecessary greenhouse gases emissions and facilitates the management of the process, including the emission control.

Our technologies allow to process the powders in elevated temperatures in oxidizing or controlled atmospheres. Whether it is roasting, debacterization or calcination process, Spirajoule is capable to perform a variety of thermal treatment and reactions. Technology is proven in many types of industrial processing, including:

  • food treatment: debacterization, pasteurization, toasting, roasting
  • chemical reactions: dehydration, calcination
  • volatiles removal and reclaiming the raw materials
  • pyrolysis treatment: low, medium and high temperature pyrolysis

Thermal powder processing sized to the need

Successful management of the powders and bulk products often requires reliable thermal solid processing. Whether it is preheating the product during the production, or influencing its physical and chemical properties, removal of moisture or devolatization of minerals, our solution helps you with the efficient thermal solids processing by treating bulk solids in any required production temperature.

To thermally process the minerals, granules and powders we use an exclusive, electrically powered technology of Spirajoule: electrically heated screw conveyor. During the solids processing, the screw ensures gentle material transportation along the reaction chamber, while the heat necessary to treat material is given directly by the screw itself. This type of treatment ensures both, high efficiency of heat transfer and extremely controllable processing conditions. As our screw is heated by the electricity, the adjustment of temperature of solid processing is easy and remains fully in the hands of operator.