What is Smelting?

Mary McMahon
Mary McMahon

Smelting is a process for extracting usable ore from mixed deposits where people find ore bound with other metals, rock, and extraneous material. It is very unusual to find deposits of pure ore and this method allows people to separate out useful metals. The invention of this process was an important step in the development of human societies, allowing people to make more complex metal products and alloys.

Smelting uses high temperatures to extract ores.
Smelting uses high temperatures to extract ores.

In the smelting process, people heat the material with an agent to trigger a chemical reaction. Although people often refer to smelting as another form of melting, simply melting material is not enough. The chemical reaction is necessary to force the desired ore to precipitate out, and it may be helpful to add a flux to bind with particulate materials, forming slag, a mass of unwanted material that will settle to the bottom of the furnace where people do their smelting.

Aluminium smelting is an industrial process used to extract the metal aluminium from aluminium oxide, or alumina.
Aluminium smelting is an industrial process used to extract the metal aluminium from aluminium oxide, or alumina.

As the ore precipitates out and gathers together, density changes in the composition of the material will cause it to form layers, allowing the operator to skim off the desirable ore. After the smelting is complete, people can take out the byproducts and discard them, although sometimes there are uses for them, such as combining them in aggregate concrete mixtures. The yield from a given smelting run varies, depending on the quality of the base product and what kind of ore people are attempting to extract.

People need to control the conditions carefully while smelting. The heat must be appropriate to the ore and the furnace requires good air circulation to fully heat all of the material, avoiding situations where it forms masses and does not have a chance to react chemically while in the furnace. People also need a nonreactive furnace lining and must be careful with certain substances because they can produce toxic fumes and may make people sick.

Industrial metals production relies on a number of processes to get usable ore out of deposits. It can be a painstaking procedure. Companies weigh the value of the ore they are extracting against the costs of extraction to determine if smelting is an efficient and appropriate processing method. In some cases, ore may be left alone because it would cost too much money to extract, even if it is valuable. People in the area around a metal mine may notice discarded waste material with traces of the metal that would be too expensive to recover inside.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


I was thinking about doing some smelting for a Medieval and "Steampunk" fair, does anyone know which type of metal would be a good one to start smelting with?

I know that iron and bronze was used the most during that time period, but I heard that they are harder to smelt than other metals. Should I start with smelting copper or tin? Are they any easier to work with or should I just stick to smelting iron?

Sorry for so many questions, but this seems like a smart place to ask. Any help would be great!


So what does smelting look like today? I'm sure it's still a major industrial undertaking, but what does it look like in modern times? Can anybody run through the process for me?


@Jacques6 - Metallurgy is amazing when you think about the science behind it. The inventor must have been a really smart person to come up with it. They must have seen metal melting and decided to try to imitate it. Humans imitate nature for a lot of their inventions.

Metal smelting in any form has given humans leaps and bounds in technology. Think of the Ancient Egyptians. They smelted bronze, iron, gold and silver. Most of their weapons were made from bronze and one of the earliest known iron blades was found over there.

When most people think of gold, they think of the golden tombs and golden treasures of Ancient Egypt. Egyptians mastered gold metallurgy early on, which is why they were considered to be such a wealthy nation.

The reason Egypt got invaded so often probably has to do with the fact that they flaunted their gold. They had easier access to it than most countries, so of course other countries would want to get it.

Why work hard mining gold and smelting it, when the Egyptians had done all the work? Honestly, I'm amazed Ancient Egypt survived as long as it did with all the greed back then.


It's hard to believe that smelting has been around for so long. With how limited technology was, I'm surprised our ancestors even discovered metallurgy.Who thought of a smelting furnace? Who thought to mine the metal -- or even that they could make a fire hot enough to shape metal?

It always fascinates me what humans have discovered over the years -- smelting is definitely one of them. Unfortunately since it was such a long time ago, there's no real way to figure out who invented smelting or the smelting furnace.

I guess whoever first saw gold thought it was valuable -- but I still would love to know how they decided that making into coins was better than carrying it around as chunks. I guess that once they figured out smelting gold, it would be easy to smelt other metals.

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