What does mean sulfur has auto-ignition Temperature 248-266C

[taregg]

same question.

 

[UltrafastPED]

"The Autoignition Temperature - or the minimum temperature required to ignite a gas or vapor in air without a spark or flame being present" ... see http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html

That it has a range means that there are conditions other than temperature which matter. These will often be humidity related, either of the air, or the moisture content of the material.