ROTAX-2® Rotary Kiln

The ROTAX-2® rotary kiln is the culmination of over 100 years of experience designing and building kilns. As reliable as it is cost-effective, it’s second to none.

Rotax kiln_FLSmidth
  • The basics
  • Design
  • Maintenance

Key benefits

  • Proven operational reliability
  • High production capacity
  • Saves energy
  • Exceptional durability
  • Low maintenance
  • Saves space
  • No need for realignment
  • Low investment and operating costs

How it works

FLSmidth has been building kilns since the late 1800s. From calculating loads and stresses to optimising each and every part of your plant for top efficiency, we know what it takes to dimension exactly the kiln you need.

The ROTAX-2® is a two-support rotary kiln system with high production capacity yet minimal heat consumption and space requirements. And with just two foundation elements, it also saves construction time and expense.

ROTAX-2 features

The ROTAX-2 rotary kiln installations feature a redesigned tyre attachment system that enables the kiln shell to expand radially, eliminating the need for lubrication as well as wear between tyre and kiln.

It sports a unique friction drive system that connects the drive directly to the supporting rollers – kiln rotation is driven by friction between the rotating support rollers and the kiln tyre.

Tangential tyre suspension

The ROTAX-2 suspends the kiln concentrically inside tangentially suspended tyres. This design allows the kiln shell to expand freely, completely eliminating the risk of shell constriction and the need for tyre migration monitoring systems. It ensures reliable transmission of drive power under any operating conditions, eliminating the need for lubrication as well as wear between tyre and kiln.

Graphite seals

The graphite seals at the inlet and outlet of the kiln reduce false air intake yet allow enough flexibility to follow the kiln’s movements.

The seals require no greasing and are practically maintenance-free.

Additional design details

Self-adjusting roller suspension maintains constant contact with all four supporting rollers; ensures efficient transmission of torque and minimises stresses that cause pitting and cracks

Kiln alignment not affected by settling of the foundation – makes periodical realignment unnecessary

No kiln girth gear and few supporting rollers – means low maintenance costs
Relatively slow speed at the kiln inlet lessens dust circulation, reducing kilocalorie consumption and facilitating operation

Easy maintenance

All parts of the ROTAX-2 rotary kiln are visible – a feature that simplifies both inspection and maintenance. Optimal mechanical reliability and tangential tyre suspension eliminate maintenance steps and wear parts compared with traditional kilns.


Most mechanical problems with rotary kilns are caused by the conditions below. Regular inspections of the kiln can help you avoid:

1. Kiln ovality – make sure that the kiln shell’s radius of curvature does not change unacceptably during the kiln’s rotation.

2. Kiln crank – check for red spots on the kiln shell and misaligned kiln shell sections.

3. Axial kiln balance – measure trust face temperatures to make sure the axial forces are not too large.
Kiln maintenance
Kiln maintenance