Thorium Element Properties and Information
Thorium Element Properties and Information
Thorium is 90th element on the periodic table. Elements are arranged in the periodic table on the basis of the atomic number. Atomic number is the number of protons in the nucleus of the atom. Thorium has an atomic number of 90. It is located in the Group ‘Actinides’ and Period 7 of the periodic table of elements. It is denoted by the symbol ‘Th’. The name is derived from ‘Thor’, the Scandinavian god of war.
Jöns Jakob Berzelius analysed a mineral in 1829 which was sent to him by a mineralogist who claimed that that mineral had never been reported before. A new element got discovered which was called Thorium and that mineral was later called Thorite.
Naturally occurring thorium is extremely abundant in thorium-232; also, it is the 41st most abundant element. The thorium which is used worldwide is extracted from monazite sands.
Physical Properties
- Thorium is a weekly radioactive element which has a bright-silvery appearance.
- The atomic mass of thorium is 232.04.
- The melting point of thorium is 1750°C.
- The boiling point of thorium is 4790°C.
- The density of thorium is 11720 in S.I. units at 20°C.
- Thorium is paramagnetic in nature.
- The crystal structure of thorium is face-centered-cubic.
- Thorium becomes a superconductor below the temperature of 1.4 K.
Chemical Properties
- Thorium is a highly reactive metal.
- Thorium is an electropositive element.
- Finely divided thorium ignites spontaneously in air.
- The reaction of pure thorium with air is slow; but, if the thorium is contaminated with dioxides then the reaction is fast.
Thorium dissolves readily in hydrochloric acid and also in nitric acid with the aid of a catalyst. It does not dissolve readily in most common acids.
Methods of Production
- Acid Digestion: The thorium containing sand is contacted with 93% sulfuric acid at temperature of 210-230°C for about 5 hours. The mass of the sand used is twice that of sulfuric acid. The mixture is then cooled to 70°C. It is also diluted to ten times its volume by cold water which causes the residual monazite sand to sink at the bottom of the vessel and the rare earth metals and thorium to remain in the solution. The separation of thorium is done by maintaining a pH of 1.3; the rare earths do not separate until the pH is 2.0.
- Alkaline Digestion: The thorium containing sand is contacted with 30-45% sodium hydroxide at temperature of 410°C for about 3 hours. This is followed by filtration where the thorium and rare earths as hydroxides get in the filter cake. The rare earths get removed after a series recrystallisation steps. Further, the residual cake is filtered; and, addition of 47% sodium hydroxide results in precipitation of thorium at about pH of 5.8.
Relevance in Chemical & Related Industries
- Ceramics: Thorium dioxide is used to make high-temperature ceramics either as a primary ingredient or a secondary ingredient.
- Glass: Thorium dioxide increases the refractive index of glass materials and decreases its dispersion.
Relevance in Other Industries
Nuclear Energy Potential: Thorium is being studied to be a potential for nuclear energy because thorium is more abundant than uranium. Tapping into it can solve energy problem of the world.
Health Effects on Exposure
- Breathing: Continuous exposure at workplaces has potential to cause lung and pancreas cancer.
Accumulation: Thorium gets accumulated in bones, it can cause bone cancer.
Effects on Surroundings
- Large releases: Large releases of thorium has potential to harm the environment; plants, animals, aquatic life-forms.
- Waste Disposal: Improper waste disposal contaminates the soil.
References:
https://en.wikipedia.org/wiki/Thorium
https://www.lenntech.com/periodic/elements/th.htm
https://www.rsc.org/periodic-table/element/90/thorium
