Dealing with hot iron is not really a hot iron ;o))

Some practical means are:

a) Wavelength, as referenced in:

Design of a Low-Cost, In-Situ, Non-Contact, Temperature Sensor
http://www.nrel.gov/ncpv_prm/pdfs/papers/101.pdf

Si Wavelength Sensitive Photodiodes
http://www.gigahertz-optik.de/en/tutori...iodes.html

Or

b) The optimum tool, a "Pyrometer"

Principles of Non-Contact Temperature Measurement
http://www.raytek-northamerica.com/admin/fil...evB_LR.pdf

I guess, that a local supplier of pyrometers should be
available. Take a google with "pyrometer".

Another idea would be a simple CMOS- chip video camera
even out of toy applications mounted into a welding
helmet or some welding glasses in front and a simple
peak detector (timing + comparator).

Small hint: All sensors are "looking" at the rods -
a lot of dust and fumes are typical for this kind of
industry. So take care of some means, to keep the
optics clean.
Example: Plastic foils slowly advancing in front of
the optics.

By the way, industrial waste burning is quite similar
in terms of high temperature and fumes + dust.

So, hope it was of some assistance

wrotto