Rotary kiln vs roller hearth kiln – challenging the status quo
Roller hearth kilns equipped with silicon carbide elements have been the standard for the calcination process in cathode production for many years. But what if a rotary kiln would be a better option? Kanthal would like to challenge the status quo.
Being a trusted partner to numerous furnace builders across the globe, Kanthal provides state-of-the-art heating elements to all types of kilns and furnaces. For the calcination process in the cathode production, Kanthal usually offers silicon carbide elements for roller hearth kilns.
But are roller hearth kilns really the best option for this specific heating process? Sachin Pimpalnerkar, Global Segment Manager for Renewables at Kanthal, says no.
Rotary kilns have the potential to improve energy efficiency, temperature uniformity, service life and productivity for cathode manufacturers
“Based on our vast experience from other industries and applications, we’d like to argue that rotary kilns have the potential to improve energy efficiency, temperature uniformity, service life and productivity for cathode manufacturers,” he says.
Let’s have a look at the arguments:
Improved energy efficiency
Rotary kilns have a higher efficiency. Roller hearth kilns need trays (saggars) to carry the cathode precursors, and heating up the trays consumes energy. Rotary kilns do not need trays to carry the cathode precursors, so energy is not lost in the process.
Better temperature uniformity
The rotation of the retort or rotary tube causes the powder to move, resulting in more uniform heating and temperature within the powder. This in turn means a product of uniformly good quality. In roller hearth kilns, the temperature of the cathode powder can vary depending on the position of the tray, leading to variations in product quality.
Longer service life
In rotary kilns, the heating elements are not directly exposed to the furnace atmosphere containing the cathode material. That means the service life of the heating elements is significantly longer, resulting in lower maintenance costs.
In rotary kilns, the rate of heat transfer is faster due to the rotation of the powder.
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