Editing Bessemer process (section)

===Process===
When the required steel forms, it is poured into ladles and then transferred into moulds while the (lighter) slag is left behind. The conversion process, called the "blow", initially took approximately 20 minutes. During this interval, the progress of the oxidation of the impurities is judged by the appearance of the flame in the mouth of the converter. The human eye was later replaced by photoelectric methods of monitoring the flame, increasing ultimate precision. After the blow, carbon is readded to the liquid metal and other alloying materials are added.

A Bessemer converter could treat a "heat" (batch of hot metal) of 5 to 30 tons at a time.<ref>{{cite web |url=http://www.steeltalk.com/bessemer_convertor.php |title=Bessemer Converter |website=www.steeltalk.com |access-date=14 January 2022 |archive-url=https://web.archive.org/web/20080117065932/http://www.steeltalk.com/bessemer_convertor.php |archive-date=17 January 2008 |url-status=dead}}</ref> They were usually operated in pairs: one was blown while the other was filled or tapped.