molten metal from the 400 ton mixer.
Pig iron from the blast
furnaces was brought to the Bessemer department by rail in 50 ton
ladles. The ladle was lifted by a 100 ton overhead crane and poured
in to the mixer. The filling spout and lid was offset from the delivery
spout and can be seen above and to the left of the stream of iron.
The mixer stored molten
iron, equalling out the composition of the iron. Think of the mixer
as a huge refractory lined steel drum that could be rotated about
its axis. It had no heat input other than fresh molten iron. Molten
iron is being poured out of the mixer into a ladle standing on a weighing
In the foreground are
a couple of slag pans (either side) and a couple of scrap kibbles
(resembling large sugar scoops with lifting lugs). Leftover slag was
dumped in to the pans after each bessemer blow and the kibbles were
used to tip scrap steel into the converters to adjust the temperature
of each blow.
The mixer was refractory
lined, and was subject to wear just like any other such vessel. Running
repairs were carried out at weekends when it was almost empty but
barely cool enough to allow the bricklayers access. Yes, it is unthinkable
in this day and age, but they went inside the vessel when it was still
hot - there was no alternative.
Steelmaking required 100 to 150
tons of pig iron every two hours.