What role does the afterburner serve in a crematory?

The afterburner in a crematory plays a critical role in ensuring efficient combustion by facilitating the burning of any unburned materials that may not have fully combusted in the primary chamber. This component helps achieve higher temperatures and better airflow, which contributes to the complete incineration of organic matter, thereby minimizing residual ash and emissions. This process is essential not only for the efficiency of the cremation but also for adhering to environmental regulations regarding emissions.

The other options do not accurately describe the primary function of the afterburner. While the afterburner does not ignite the initial flames, reduce bone fragments, or preheat the primary chamber, it focuses on maximizing the combustion process for what remains after the initial cremation phase, ensuring that all combustibles are effectively burned.