Growing demand for lithium-ion batteries puts pressure on manufacturers to improve all steps in the product chain, including the heating processes. With electric rotary kilns, lithium refineries could cut carbon dioxide emissions in their heating processes to zero if renewable energy were used. At the same time, cathode producers could benefit from lower energy consumption and higher productivity.
The demand for lithium-ion batteries is driving growth in the battery industry across the entire production chain. Lithium refineries as well as cathode and anode producers are planning new facilities or suiting up to increase production. With the emphasis on improving energy efficiency found in every sector of manufacturing, those in the battery industry also will evaluate and improve the steps of each process throughout the production chain. That includes the choice of heating solution.
Cathode Production Using Rotary Kilns
For the calcination process in cathode production, electric heater manufacturer Kanthal has traditionally offered silicon carbide elements for roller-hearth kilns. But are roller-hearth kilns the best option for this specific heating process? Sachin Pimpalnerkar, global product manager at Kanthal, says no. “Based on our 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,” Pimpalnerkar says.
“Just to mention one example, the trays that are needed in roller-hearth kilns to carry the cathode precursors consume energy as they absorb the heat, and they also transport heat out of the kiln,” he continued. “With a rotary kiln, you only heat the material itself, and hence, there is a minimal heat loss associated with carrying the material through the kiln.”
In the lithium refining steps such as the sulphuric acid roasting process, indirect rotary kilns with gas burners are already being used, Pimpalnerkar noted. By replacing gas-fired heating with electric heating in this process, lithium producers stand to make cost, efficiency and environmental gains.
“If powered with renewable energy, the entire process releases zero CO2 emissions while the working environment is not contaminated with CO2, NOX, CO, SOX or noise pollution,” Pimpalnerkar explained.
The efficiency benefits with electric heating compared with gas heating are also significant.
“When heating with gas, you lose a lot of hot air through the exhaust – and lost heat represents inefficiency,” Pimpalnerkar said.According to Pimpalnerkar, there is a general misconception that electric heating is an unproven technology. “It’s important to remember that we aren’t changing the actual process, just the way the heat is put in,” he added. “We do this using our standard heating elements that are already being used in the lithium-ion industry and for which we have extensive references.”