bloomeries were the first reall attempts at production based iron smeting. The folks would use whatever they had as low grade ore (iron nickel meteorites being an exception because they could be heated and directly forged into a steel and those were few and far between).
Bloomeries alwayys produces an Iron Silica mix called Fayalite and every iron culture seemed to start with iron blooms because it was n easy discovery from a campfire where some lower content iron ore (bog ore, hematite, siderite, pyrite etc) could be converted into this mush
called iron bloom and continued heating and pounding would lead to a
more refined product that could be used for weapons .
ALSO FROM WIKIPEDIA (under Iron bloomeries)
of ferrous metallurgy
The onset of the Iron Age in most parts of the world coincides with the first widespread use of the bloomery. While earlier examples of iron are found, their high nickel content indicates that this is meteoric iron. Other early samples of iron may have been produced by accidental introduction of iron ore in bronze smelting operations. Iron appears to have been smelted in the West as early as 3000 BC, but bronze smiths, not being familiar with iron, did not put it to use until much later. In the West, iron began to be used around 1200 BC.
Fayalite and Forsterite are two minerals that form OLIVINE. They are separate forms of silicate (Mg and Fe). The increasing appearance of fayalite "Bloom" in the Neolithic may have been accidental introduction of olivine boulders into fire pits (or as some say, an accidental introduction into bronze making)
The temperature of "Smelting" is low enough to actually occur in big enough campfires and, after the fires had burnt out and cooled, digging into the ashes had revealed the iron (fayalite) bloom. Industrial use of an actual manufactured bloomer came shortly thereafter and iron , of varying purities was able to be made.
It didn't require any charcoal smelting for purification. The blooms were merely refined in the next fire until it was relatively silica and carbon free.