As far as I'm aware, there's written/archeological evidence of iron smelting was being practiced in Anatolia (modern-Turkey) by at least 1200 BCE, with suspected smelted-iron artifacts dating back to ~2000 BCE. It's relatively easy to tell smelted iron apart from meteoritic iron. Meteoritic iron will almost always contain a large portion of nickel or cobalt in it, while smelted iron usually contains embedded siliceous slag - both can be discerned through chemical or microscopic analysis.

Here's a good write up on the subject by Dr Nathaniel Erb-Satullo (specialist in Western/Near East archeology, Archeological Science - Cranfield University, Department of Anthropology - Harvard University): https://www.tf.uni-kiel.de/matwis/amat/iss/kap_b/articles/literature_evaluations_old_swords/general_2019_erb-satullo_iron_neareast_review.pdf

>one argument that was made, was that when iron smelting becomes possible... why wouldn't it rapidly replace bronze?

Smelting iron was a much more complicated process than smelting copper or tin. In the early days, iron was never fully melted - the furnaces they had at the time just weren't hot enough - which makes it harder to reduce the ore and remove impurities.

Instead, when pre-modern ironworkers smelted iron what they were actually doing was burning off the oxygen/sulfur/etc. locking the iron in the ore minerals, usually by heating them in a carbon-rich environment of a charcoal furnace (oxygen will rather bond with carbon instead of iron). The temperature of these reactions happen at a much lower temperature than the melting point of elemental iron (700-1200'C vs 1500'C). Certain "fluxes", like siliceous minerals or limestone, further lower or aid the ore reduction reaction or process.

Early iron smelters had to figure out several problems (all without the aid of modern chemistry knowledge), namely how run their furnace to optimize iron production. Too little draft air, the furnace doesn't get hot enough for reduction to happen. Too much draft air, excess air cools the furnace or re-oxidizes the iron. Furnace runs too hot, the iron starts sucking up carbon too fast and transforms into useless pig iron. Etc.

Being a complicated process, it was also easier to keep secret by those that did figure it out. Since early iron smelters had a vested interest in maintaining a monopoly on producing this very useful and valuable material (at one point in history, iron was worth as much as gold in weight), they didn't just share their knowledge and craft with anyone. Hence, most early iron production seem to have been conducted and exclusive to a small group related to the Hittites in Anatolia for most of the late bronze age. The Late Bronze Age collapse likely caused this small group of secretive iron smelters to migrate and proliferate the technology to the rest of the Old World, as we start seeing common use of iron by 900-800 BCE.

I completely forget where I read this, so apologies for this but

There's a region of Russia with iron-based red sand. It is theorized that this was where we got the first refined iron from as all you need to refine this red sand is a clay crucible and a particularly hot fire.

This red sand is only present in any significant quantity in this region of Russia, so until methods of getting refined iron from virgin ores became available it was extremely rare.

A similar thing happened with steel; humans knew how to make steel for thousands of years, it just wasn't practical to use for anything other than high-end weapons and tools until someone figured out how to mass produce it in the 19th century.

What exactly is the Roman Era they're referring to? Are they saying that romans invented Iron smelting?

I'd direct your research if you're willing towards ancient India and China. From my cursory investigation they were smelting iron before the founding Rome.

Edit- It also seems the person arguing that "blooming isn't really smelting" is arguing semantics. Since blooming is in fact a method of smelting

Surely at the beginning of the Iron Age. Pretty sure the Assyrians were the first empire to “mass” produce iron.

1324 BC was when King Tut was buried. his tomb has a steel dagger made from an iron meteorite.

Wasn't it discovered that an Egyptian Pharaoh had a dagger gorged from a meteorite? I may be mistaken.

There are hundreds of examples of iron smelting with soft evidence dating back to well before the Romans. Those examples failed to produce usable iron and instead produced cotton candy in spite of the use of iron ore in the process.

Soft evidence. I'll be here all week folks. Tip your waitresses.

There are widespread archaeological finds going back at least to 1200 BCE. Is that hard enough?

And iron did largely replace bronze, but mostly for economical reasons. It's only with steel you get a clear superiority over bronze.

Iron is not necessarily better than bronze, it's definitely easier to obtain, but bronze had many advantages to iron such as it's non-corrosive traits that made it necessary for sea faring cultures.

That being said, throughout the world iron had it's users as far back as 3000 BCE, and as we see in the near east, even further back.

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