Extraction of antimony and niobium with tributyl phosphate from fluoride-ammonium solutions. ... A noticeable effect on the extraction of tantalum by liquid-liquid extraction is exerted by the ...

Best Solution Under Extreme Conditions. Tantalum and niobium are characterized by high corrosion resistance and ductility at elevated temperatures. These properties …

The direct precipitation of niobium and tantalum from alkaline solutions was investigated. Fig. 1 gives the precipitation yield of niobium by addition of a calcium acetate solution to a sodium hexaniobate solution at pH ~ 11. The calcium acetate complex was chosen for its high solubility in water (3.1 mol/kg of H 2 O at 25 °C) and its weak …

The approach consists of several sequential steps involving tantalum and niobium leaching, solutions purification, precipitation, calcination and final recovery of high purity metals as oxides.

Niobium and tantalum primary minerals are naturally occurring complex oxide ores, majorly of low grade deposits with chemical content of mainly Nb 2 /Ta 2 O 5 …

Niobium and tantalum are transition metals that are almost always found together in nature because they have very similar physical and chemical properties. Their properties of hardness, conductivity, and resistance to corrosion largely determine their primary uses today. The leading use of niobium (about 75 percent) is in the production …

H.C. Starck Solutions supplies tantalum and niobium sheet and plate with a cold-rolled and chemically cleaned surface. Because of its strength and workability, very thin sheets of tantalum can be clad to other surfaces, providing superior corrosion protection and cost effectiveness. All tantalum sheet and plate is visually inspected for slivers ...

Niobium and tantalum primary minerals are naturally occurring complex oxide ores, majorly of low grade deposits with chemical content of mainly Nb 2 /Ta 2 O 5 and oxides of Fe, Mn, Sn, Ti and other metal oxides. Over the decades, researchers have extensively and consistently investigated the extraction and recovery of Nb and Ta from …

ABSTRACT Niobium and tantalum are found together in natural minerals. Leaching with concentrated acid solution or alkaline roasting followed by water/dilute acid leaching results in a solution containing these two metals. In this work, we reviewed the extraction and separation of Nb(V) and Ta(V) from leach liquors in the absence and …

The most important parameter in determining the purity of niobium in the strip solution is TOA concentration in the organic phase (contribution 49.85%), followed by O/A ratio of stripping (contribution 47.20%). The developed process resulted in 98.88% pure niobium and tantalum of 98.08% purity.

The most impressive result was obtaining 70 mL of high purity niobium solution of tantalum content 0.027 ppm (in relation to Nb) with 88.4% yield of niobium from a solution of Nb:Ta, weight ratio ...

The corrosion resistance of niobium, tantalum and Nb-20, 40, 60 and 80 wt% Ta alloys in boiling 20, 40, 60 and 80 wt% H 2 SO 4 solutions is studied using the mass-loss technique. The corrosion rates of all materials increase with acid concentration and diminish initially with time.

The extraction of Nb and Ta were performed using 35% (v/v) Cyanex 923® diluted in Solvesso with high yields, 97.7% for Nb, and 99.6% for Ta. Nb stripping. The stripping solution used for the selective stripping and separation of niobium had the following.

The corrosion resistance of niobium, tantalum and Nb–20, 40, 60 and 80 wt% Ta alloys in 5, 10, 15 and 20 wt% HCl and 20, 40, 60 and 80 wt% H 3 PO 4 solutions at boiling point, 150°C and 200°C is evaluated using the mass-loss technique. The corrosion rates of all materials increase with acid concentration and temperature.

Their chemical characteristics, such as small ionic size and high electronic field strength, significantly reduce the potential for these elements to substitute for more …

About the Tantalum-Niobium International Study Center (T.I.C.) An international, non-profit association founded in 1974 under Belgian law. Around 90 members from over …

This type of solution is widely used in the technology of tantalum and niobium compounds in raw material digestion, liquid-liquid extraction, precipitation, and re-pulping of hydroxides, and in ...

The most impressive result was obtaining 70 mL of high purity niobium solution of tantalum content 0.027 ppm (in relation to Nb) with 88.4% yield of niobium from a solution of Nb:Ta, weight ratio ...

The solution spectra of the organic phases were measured in CCL, (of spectrochemical purity) in a 0.52 mm NaCl cell, allowance being made for solvent absorption. meter in the RESULTS Extraction behaviour Table II shows the dependence of the extraction of niobium and tantalum in oxalate solutions, upon the sulphuric acid concentration, with …

In the stripping of niobium from the organic solution, the phase separation was much easier with 1N solution as a stripping medium than with water. finally, tantalum and niobium having a purity of ...

Comparative study of extraction of tantalum(V) and niobium(V) with octanol and tributyl phosphate was made. The data on distribution of tantalum(V) and niobium(V) between octanol and hydrofluoric and hydrofluoric-sulfuric acid aqueous solutions were obtained. The flowsheet for preparation of pure tantalum and niobium oxides was developed.

The recovery of niobium and tantalum from alkaline solutions has been investigated. We showed that, instead of neutralizing the Nb and Ta solutions by mineral acids, calcium-bearing reagents can be used to quantitatively precipitate Nb and Ta. Calcium chloride, calcium acetate and calcium hydroxide were found to be efficient at …

Niobium and tantalum are two strategic metals widely explored and with several industrial applications. Both elements are extensively applied in aerospace, automotive, construction, alloys, and ...

Niobium and tantalum share many physical and chemical properties: their high ductility at room temperature makes these two metals the most versatile of the refractory metals 1 and both are protected by a pentoxide (i.e., Nb 2 O 5 and Ta 2 O 5). Niobium is a key component in high-temperature nickel based superalloys.

Precipitation from fluoride solutions of niobium, tantalum, and titanium containing ammonium, sodium, potassium, and calcium ions was observed when the concentration of niobium, tantalum, and titanium was 0.8–1.2 mol/L. This means that poorly soluble com-pounds (the complex fluoride salts) are formed in the system.

Comparison of Supercontinent Cycles in the Metallogeny of Niobium. A. Tkachev D. Rundqvist N. Vishnevskaya. Geology. Geology of Ore Deposits. 2020. Abstract The distributions of niobium mineral deposits and their resources on the geological time scale are analyzed. The sampling list includes 45 mineral deposits with their individual …

Providing both thermal and oxidation resistance, tantalum carbide and niobium carbide are also used as grain growth inhibitors in tungsten carbide and as intermediates in the cemented carbide process. Characteristics. Tantalum Carbides. Brown to dark brown powder having a cubic structure; Density @ 14.3 g/cm³; Melting point @ 3880 deg C ...

The solution chemistry of niobium has received some attention from the radioactive waste community because of isotopes such as: 91 Nb (half-life: 68 y), 93m Nb (half-life of 16.3 y), a fission product, and 94 Nb (half-life of 20 × 10 3 y), a neutron activation isotope formed in nuclear power plants.

The corrosion resistance of niobium, tantalum and Nb–20, 40, 60 and 80 wt% Ta alloys in 5, 10, 15 and 20 wt% HCl and 20, 40, 60 and 80 wt% H3PO4 solutions at boiling point, 150°C and 200°C is ...

Applications of Niobium and Tantalum in the space travel industry: Niobium: An alloy called Inconel 718 which consists of 50% nickel, 18.6% chromium, 18.5% iron, 5% niobium, 3.1%. molybdenum, 0.9% ...

Parameters for the preparation of concentrated tantalum, niobium, and titanium fluoride solutions by dissolution of their oxides or hydroxides in hydrofluoric acid were studied. Anatase titania, niobium oxide, and tantalum oxide calcined to 900°C were found to have high dissolution rates. Solid phases separated upon the dissolution of …

The isoelectric region of tantalum solubility is 8.0 x 10/sup -6/ mole/l. and niobium 1.4 x 10/sup -5 mole/l. Effects of H/sup +/ and OH/sup -/ concentration on solubility of Ta and Nb acids were evaluated. It was revealed that Ta and Nb ion monomers were formed at the initial stages of solubility.

Studies of niobium, tantalum, and titanium fluoride solutions are few and frequently concern dilute solutions, whereas stronger solutions are used in practice for the …