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Indirectly heated rotary kilns

A revolutionary concept for the thermal processing of mineral ores

Our electrically heated indirect rotary kilns are a versatile solution for the thermal treatment processes up to 800°C. Particularly effective for beta spodumene to lithium sulphate conversion, they support carbon footprint reduction and carbon capture ambitions in applications where process CO2 emissions are an issue.

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Key benefits of our indirectly heated rotary kilns

  • Minimal maintenance requirements

    The heavy-duty, yet simple, construction of our indirectly fired rotary kilns ensures low annual and online maintenance requirements. This includes an automatic lubrication system, designed to facilitate the continuous movement of rotating parts while limiting component wear.

  • Built for a service life of 25 years plus

    We designed the indirect rotary kiln with lower stress limits to promote longer service life. It also comes with a highly robust outer steel shell.

Our indirect rotary kilns can handle a wide range of raw materials – from alumina and bauxite to vanadium salts, and many in between, including the highly effective treatment of beta spodumene in lithium processing applications, and the calcination of minerals up to 800°C. We can deliver kilns from 1m to 6m diameter and up to 90m long. Lower-temperature units are available with natural gas heating in the event electric heating is not a viable option.  

Features of indirectly heated kilns

  • Kiln shell

    The robust steel shell is designed to handle any applications.

  • Kiln shell internals

    Our shell internals ensure optimised heat transfer for any process.

  • Kiln riding rings

    Fully floating or tangentially suspended riding rings ensure smooth kiln rotation.

  • Sleeve bearings

    Proprietary sleeve bearings deliver vibration free operation and easy maintenance.

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Frequently asked questions

FAQs for indirect rotary kilns

A rotary kiln is a type of industrial furnace used for thermal processing of various minerals and ores. It consists of a rotating cylindrical drum, slightly inclined from the horizontal, down which raw materials and are heated. 

The difference between a direct and indirect rotary kiln lies in how the heat is applied. Direct heating involves the combustion of fuel inside the kiln shell with heat transferred directly to the material being processed. In an indirectly heated system, heating occurs externally, with heat transferred through the shell to the material inside.

Our indirectly heated rotary kilns are particularly relevant for the conversion of beta spodumene to lithium sulfate. They can also handle a range of other applications, including the thermal treatment alumina, bauxite, catalyst, clay, dolomite, diatomaceous earth, ferro-nickel/ferro chrome, iron ore, ilmenite, lightweight aggregate, limestone, magnesite, petroleum coke, phosphate, rate earth elements, soda ash, trona, and vanadium.

Yes! We have developed a complete indirect rotary kiln acid roasting technology specifically for the conversion of beta spodumene into lithium sulfate. Based around our indirectly heated rotary kiln, this simple but effective system ensures highest possible lithium recovery while reducing the cost and environment impact of the process. 

We believe our indirectly heated rotary kilns are well-placed to support carbon capture ambitions where process CO2 are an issue. We have the expertise and experience to analyse your application and suggest an innovative, tailor-made solution. Trials or small production campaigns are possible in our well-equipped technical centre.