The gold melting point is 1,064°C degrees Celsius (1,948°F degrees Fahrenheit). The numbers provided are for the pure gold melting point (24 karat = 100% gold). However, if you use gold that is in an alloy (a combination of two or more metals together) the melting point can change. For example, combining gold, silver, copper, and zinc creates yellow gold. While rose gold is a combination of 75% gold and 25% copper which would be 18 karats rose gold. White gold would be a combination of gold, palladium, nickel, and zinc. By combining metals into alloys, it changes the properties of the metal. The gold melting point of 14 karat yellow gold would be 1550°F degrees Fahrenheit due to the lower purity of gold and the higher purity of silver, and zinc thus lowering the melting point.
Gold melts when it encounters mercury due to a process called amalgamation. This combination of metals is called an amalgam which is a metal alloy. With the melting point of mercury being at -38.83°C degrees Celsius or -37.894 degrees Fahrenheit it would lower the melting point of gold and raise the melting point of mercury where it becomes a mix between a semi solid and liquid state depending on the concentration between the gold and mercury in solution. Separating the gold from mercury can be done by using an acid that dissolves mercury but does not dissolve gold therefore leaving pure gold behind.
Smelting is the process of momentarily converting a solid into a liquid by heating it to the melting point, typically with the aid of a kiln, furnace, or torch. Impurities separate from gold after the heat dissipates and the metal returns to equilibrium, and any once separated particulate is now mixed and solidified as a single piece or bar of gold.
When gold mining or prospecting the gold, you find will typically be smaller and more difficult to deal with. Therefore, melting gold into ingots or bars will make it easier to handle, store, and determine the purity making it easier to sell for its spot market value.
Most gold is melted in a crucible with flux, such as borax. The gold smelting flux assists in the separation of impure metals from solution by reacting with them to form nitrates. Simply put, the smelting flux makes it easier to remove metallic oxides, resulting in more pure gold.
Gold can be refined industrially by the Wohlwill Process or the Miller Process which both create some of the most pure gold resulting in 99.5% pure gold. When the miller process is combined with the Wohlwill process the gold produced can be upwards of 99.999% purity also known as 24 karat gold.
Propane torches can get up to temperatures of 2,000°C degrees Celsius which is well above the melting point of gold. Most crucibles can only tolerate temperatures up to 1750 °C degrees Celsius so be careful during the melting process as you risk reaching the melting point of the crucible.
Buy an electric foundry that can reach temperatures higher than the gold melting point of 1,064°C degrees Celsius (1,948°F degrees Fahrenheit).
Aqua regia is known as royal water due to its unique ability to dissolve pure gold. To use this method, you will need to reduce the gold to smaller pieces to allow for a larger surface area for the reaction to occur. Always use the proper safety precautions including proper ventilation and PPE.
Gold is melted down into ingots and bars, which are then used to make jewellery, electronics, and other items.
Impurities are removed from solution into salts as gold is melted. The impurities are skimmed off the top, leaving only pure gold.
It can make sense to melt gold if selling it as pure gold will be more valuable than selling it in its current state. A gold necklace from a well-known jewellery designer, for example, will sell for more than the cost of melting it down. However, impure gold or gold amalgamated with mercury will possibly sell for less than its pure form until separated and purified.
The purity of gold is expressed in karats or fineness in (parts per thousand).
The amount of gold you lose during melting depends on a variety of factors, that depend on your operation and purity of gold. Melting gold, on the other hand, will result in losses ranging from 1% to 2.5 percent on average.
You can estimate how much total mass was lost by comparing the before and after sizes. This method of calculating losses, however, would not be correct if your gold was not as pure to begin with or you have alloys mixed in.
Gold is the most desirable metal on the planet due to its properties, as well as the overwhelming demand for it in the jewelry, finance, banking, and technology industries.
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