There are many people who have doubts about the
casting process to make gold coins, in this article we will learn more about
this procedure.
History
The gold smelting process is very old, there is evidence
that mentions that in the year 6,000 BC gold was already being smelted. It was
a process that was done in ancient Mesopotamia, especially in Babylon. When
gold was mined from the earth, it was crushed with simple tools, washed with
water, and poured into clay ovens to be melted down. At present, said
technology has improved and optimized this procedure. Below we explain the
current process for melting gold:
Gold smelting process
First of
all, we must clarify that the process of melting gold (smelting) should not be
confused with the process of melting gold (melting). Melting gold is the final
process, which consists of subjecting the metal to high temperatures until it
reaches a liquid state to later form gold ingots, bars or coins. On the other
hand, the gold smelting process is a previous process that consists of removing
the impurities from the gold, using heat, certain chemical products and
pressure.
As we saw in our previous article, to melt gold you
have to follow a series of steps, which are detailed below:
·
Processing:
After removing the gold from the ground, the minerals are separated from the
raw material. Generally, the gold ore is pulverized by pressure, obtaining fine
particles.
·
Chemical
removal: Gold may contain certain hazardous chemicals that must be removed
prior to smelting. For example, mercury is harmful when it is in a gaseous
state. Some gold mining processes require mercury and the ore may contain some
traces of mercury (which can adhere to the gold even after precipitation and
leaching). To remove said ore it must be heated in a retort. On the other hand,
the iron must also be removed so that it does not cause damage to the casting
materials. Iron is removed by oxidation in a forced air furnace or with nitric
acid.
·
Foundry.
The resulting particles are heated in a furnace that must be at the temperature
of the melting point of gold: which is 1,064°C. Most of the impurities are
burned off in this process; however, some metallic elements still remain.
·
Elimination
of impurities. After the raw ore is processed and melted, chemical products
are applied in order to eliminate the remaining impurities that the gold still
has (mainly metallic elements).
·
Melting:
The gold is again placed in the furnace. This time with the purpose of melting
it to be able to make ingots, bars or coins.
Coin making process
Coins are made from different metals: gold, silver,
palladium, platinum, etc. The process of making coins is as follows:
The type of currency is previously designed; this
design can take as a reference a photograph, a work of art or any other reason
(generally a computer program is used). Once the design is approved by the
Board of Directors of the Mint (of the respective country), the coin is made.
The metal, silver or gold, enters a smelting furnace, where it is shaped into a
continuous bar, which is then "cut" into individual ingots. After a
series of processes, these ingots come to have the shape of the coins we know.
It is important to note that in the case of bullion
coins (coins for investment or collection), this process is more rigorous,
since unlike conventional coins, they are coins suitable for investments. In
most cases, these coins are minted in a precious metal that has a purity ratio
of 90% or higher.
What do you think about this topic? Did you know
the Gold rate in Dubai smelting process for making coins?
