| Molecular Formula | Nb |
| Molar Mass | 92.91 |
| Density | 8.57 g/mL at 25 °C (lit.) |
| Melting Point | 2468 °C (lit.) |
| Boling Point | 4742 °C (lit.) |
| Water Solubility | Insoluble in water. |
| Appearance | wire |
| Specific Gravity | 8.57 |
| Color | Silver-gray |
| Merck | 13,6584 |
| Storage Condition | -20°C |
| Stability | Stable. Incompatible with strong bases, strong oxidizing agents, halogens, oxygen. |
| Physical and Chemical Properties | Chemical properties shiny, soft, silvery white, metal. |
| Use | The application is mainly used to make special stainless steel, high temperature alloy, superconducting alloy and super hard alloy. |
| Risk Codes | R17 - Spontaneously flammable in air R36/37/38 - Irritating to eyes, respiratory system and skin. R40 - Limited evidence of a carcinogenic effect R34 - Causes burns R20/21/22 - Harmful by inhalation, in contact with skin and if swallowed. |
| Safety Description | S17 - Keep away from combustible material. S36 - Wear suitable protective clothing. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S6 - Keep under ... (there follows the name of an inert gas). S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S27 - Take off immediately all contaminated clothing. |
| UN IDs | UN 1383 4.2/PG 1 |
| WGK Germany | - |
| RTECS | QT9900000 |
| TSCA | Yes |
| Hazard Class | 8 |
| Packing Group | II |
| Toxicity | LD50 intraperitoneal in mouse: > 10gm/kg |
| Downstream Products | Niobium carbide |
| resistivity (resistivity) | 13-16 μΩ-cm, 20°C |
| Exposure Limits | ACGIH: TWA 0.5 ppm(2.5 mg/m3); Ceiling 2 ppm (Skin) OSHA: TWA 3 ppm NIOSH: IDLH 30 ppm(250 mg/m3); TWA 3 ppm(2.5 mg/m3); Ceiling 6 ppm(5 mg/m3) |
| EPA chemical information | Niobium (7440-03-1) |
Introduction
Niobium metal element, atomic number 41, VB group of the periodic table, valence 2, 3, 4, 5; no stable isotope. There are 49 isotopes of niobium, ranging from Nb-81 to Nb-113. Except niobium 93 is stable and constitutes the natural existence of all elements in the earth's crust, all elements are radioactive and artificially manufactured. Niobium is a soft gray-silver metal similar to freshly cut steel. It is usually found in minerals together with other related metals. Due to the thin coating of niobium oxide, it will not change color at room temperature or oxidize in air. But it will easily oxidize at high temperatures (above 200°C), especially by oxygen and halogen (group 17). When compacted with tin and aluminum alloys, niobium is superconductive at 9.25 Kelvin degrees.
Discovery history
Hubbchett discovered niobium in 1801 in ore sent to England by John Winthrop the Younger, the first governor of Connecticut. The metal was first prepared by Blomstrand in 1864, who reduced the chloride by heating it in an atmosphere of hydrogen. After 100 years of controversy, the name niobium was adopted by the International Union of Pure and Applied Chemistry in 1950. Most leading chemical societies and government organizations use this name to call it. However, some metallurgists and commercial producers still refer to this metal as "niobium".
Source
Niobium is the 3 3rd most abundant element in the earth's crust and is considered a rare element. It does not exist in nature in the form of free element metal. On the contrary, it is found mainly in several kinds of ore. Niobium is found in niobite (or cobalt-aluminum), niobite-tantalite, pyrochlore, and hematoxylin. A large amount of niobium as a component of pyrochlore has been found to be related to carbonates (carbonosilicate rocks). Rich ore reserves have been found in Canada, Brazil, Congo Kinshasa, Rwanda and Australia. The metal can be separated from tantalum and can be prepared by several methods.
application
Niobium is a very important metal in ferrous and non-ferrous metals. When niobium is used as an additive in the alloy or alloyed with other metals, it can give the alloy high mechanical strength, high conductivity and ductility. It enhances the corrosion resistance of most alloys. This metal and several of its alloys exhibit superconductivity. Niobium can be used as an additive in the manufacture of high-strength, low-alloy carbon steels and microalloyed steels, which are used in oil and gas pipelines, bridges, buildings, concrete rods and automobiles. It is also added to nickel-based and cobalt-based superalloys and is a component of zirconium, titanium and tungsten alloys. Other applications of niobium are in electronics and propulsion devices, electrodes; catalysis, and vacuum tubes and high-pressure sodium vapor lamps.
Preparation
There are several ways to extract and extract niobium from ore. The method chosen depends on the nature of the ore and the end use for the metal. Some common steps in these recovery processes include ore preconcentration, crushing or opening the ore, obtaining pure niobium compounds, reducing niobium compounds to niobium metal, purifying or refining metals, and manufacturing. If niobium is extracted from niobium tantalum ore, the most important step is to separate niobium from tantalum, and the two are very similar chemically.
Iron niobium can be prepared from pyrochlore by thermal reduction in refractory-lined steel or preferably in an electric furnace reactor. Aluminum powder is used as reducing agent. Mining is a key step in niobium recovery. Separation of niobium from tantalum and impurity metals is the most important step in extracting niobium from ore. It can be achieved by several methods, including solvent extraction, ion exchange, fractional crystallization, fractional sublimation and other techniques.
High purity grade metals can be produced by reducing niobium pentoxide Nb2O5 or niobium pentachloride NbCl5 at a high temperature of 1400 to 2000°C, usually under vacuum using various reducing agents (such as carbon, hydrogen, sodium and other substances):
Nb2O5 7C→2NbC 5CO
Nb2O5 5NbC→7Nb 5CO
2NbCl5 5H2→2Nb 10HCl
NbCl5 5Na→Nb 5NaCl
Toxicity
Niobium is not reactive at normal room temperature. However, its physical forms are toxic, such as dust, powder, shavings and steam, which can cause cancer if inhaled or ingested.