Molten salts, as the name states, are simply salts that are melted. Molten salts are also known as “Fused Salts.” The properties of molten salts are different from ordinary salts in such a way that, unlike common salts, molten salts act as solid under standard pressure and temperature conditions but tend to act as a liquid when the temperatures are elevated.
To practically demonstrate the physical properties of molten salts, you can take an amount of Sodium Chloride (Table Salt) and heat it with a red flame. In order to attain a red flame, you must raise the temperature to greater than 1474°F or 801°C. After heating NaCl at this certain degree, it would transform into a liquid state.
It is the unique characteristics, features, and use of molten salt that make it special. Following, you will see some of the prominent features and the uses of molten salts.
Features and uses of molten salts
One of the most important aspects of molten salts is their ability to conduct electrical energy. Since there are larger spaces between molecules when the matter is in liquid form, more electronic charges can travel through it. This ability makes molten salts one of the best choices to use in generating electricity through different processes from renewable resources.
For example, molten salts are used in generating electricity in solar panels and nuclear energy.
Another use of molten salts is seen in infrastructure, where they are used as preventative measures for general corrosion. The thermodynamic descriptions, as well as the phase diagrams of molten salts, are quite similar to that of metals.
Moreover, the compatibility of molten salts is higher with structural alloys, which makes them a perfect choice to be used in infrastructure systems.
In general corrosion, the structural metal used in infrastructure systems is oxidized into corresponding chlorides and fluorides. This is done due to the reduction of an oxidizing agent generally present in the structural metal. So, when molten salts are used, the oxidation process slows down. This is because the molten salts are good conductors and are ionic, so it takes much more time for them to disintegrate or reduce to their chlorine and fluoride ions.
Molten salts also play a huge role in generating solar energy. The one thing that is distinctive about molten salts is that they can store heat energy from the sun during daylight. The molten salts present in the solar panel wafers can then produce electricity even when there is no sunlight. The heat energy stored in the molten salts present in the wafers transfers the energy to a nearby steam generator, which in turn produces electricity.
These molten salts can store heat energy in them for long periods of time, so it is a perfect way of utilizing energy from the sun in harsh weather conditions such as thunderstorms and heavy rains.
Many types of molten salts that have high lithium-ion conductivity are often used as electrolytes in lithium-ion batteries. However, because most salts rich in lithium-ion conductivity have higher melting points, they are generally not the best option to use in batteries other than reserve batteries.
In reserve batteries, however, they can play a part in elongating the shelf life since they are very ionic in nature. The molten salts are stored as solids in the batteries, and when it is charged, the salts get converted into liquid.
Molten salts are also used in nuclear reactors, typically in Molten Salt Reactors (MSR) and Molten Salt Energy Storage Systems (MS-ESS). Usually, fluoride salts are used mixed with any radioactive element.
MSRs have a security level that is not seen in any other kind of nuclear reactors, and it is because there is a significantly lesser risk of a nuclear meltdown. Because the salts being used in MSRs are already melted, the extremely high temperatures of the reactions taking place in the nuclear reactor do not affect the material in any way, dramatically decreasing the risk of a nuclear meltdown.
In nuclear reactors, molten salts can also be used as coolants in addition to being used as fuel. Because the operating temperature of a nuclear reactor is less than the boiling point of the salts, it acts as one of the best coolants in a nuclear reactor.
Table salts and molten salts are two different things having distinct features and characteristics. While most people know what makes molten salts, by reading this article, you will learn what makes it special. The use of solar energy and nuclear reactors are the most distinguished features that make it special. Can you think of any other use that makes molten salts special other than those discussed here?