Elemental element of titanium subgroup

The titanium subgroup is the VB group of the periodic table, and includes three elements: titanium (Ti), zirconium (Zr), and give (Hf)
.
The valence electron layer configuration of the titanium subgroup element atom is (n-1)d ² ns ² , the most stable oxidation state is +4, followed by +3, and the oxidation state +2 is relatively rare

Titanium content in the crust is 0.
56% (lane 9), is the most important mineral ilmenite FeTiO _.
3 and rutile Ti02 ₂ ore, there are other perovskites of CaTiO _.
3 , sphene CaTiSiO _.
5 and the like
.
Titanium has become a rare element due to the difficulty of extraction and the late start of research

Elemental element of titanium subgroup

1.
Refining of metals

Titanium metal has a high melting point and easily reacts with air, oxygen, nitrogen , carbon and hydrogen at high temperatures, so it is difficult to extract and expensive
.

The ilmenite is enriched to obtain ilmenite concentrate, which is treated with sulfuric acid and converted into titanyl sulfate TiOSO ₄
.

FeTiO ₂ +2H ₂ SO ₄ =TiOSO ₄ +FeSO ₄ +2H ₂ O

The leaching solution crystallizes FeSO ₄ ·7H ₂ O at low temperature
.
After filtration, it is diluted and heated to hydrolyze TiOSO ₄ to obtain H ₂ TiO ₃ , and H ₂ TiO ₃ is calcined to obtain TiO ₂

TiO _{2 is} heated with carbon and chlorine to generate titanium tetrachloride TiCl ₄
.

TiO ₂ +2Cl ₂ +2C=TiCl ₄ +2CO

CO ₂ is also generated in the product
.

Then in an argon atmosphere with magnesium or sodium for thermal reduction to obtain metallic titanium
.

TiCl ₄ +2Mg=Ti+2MgCl ₂

Metal titanium can also be refined by molten salt electrolysis
.
Using molten CaCl ₂ as a flux, and directly electrolyzing TiO ₂ in an inert atmosphere, metallic titanium can be obtained

In the early days, TiCl _{4 was} prepared by reacting ilmenite with carbon and chlorine at 900°C
.

2FeTiO ₃ +7Cl ₂ +7C=2TiCl ₄ +2FeC1 ₃ +6CO

Metal cobalt is extracted from zirconium tetraiodide ZrI ₄ by thermal decomposition at 1300°C
.

ZrI ₄ =Zr+2I ₂

2.
The nature of the element

The main characteristics of titanium metal are low density and high strength
.
Therefore, titanium has both the advantages of steel (high strength) and aluminum (light texture)

The corrosion resistance of metal zirconium exceeds that of titanium and but
.

Titanium is an active metal (E ^Θ =-1.
37V), but it is passivated at room temperature or low temperature, because a thin, difficult-to-permeate oxide film is formed on the metal surface
.
Titanium can be slowly dissolved in hot concentrated acid to form Ti ³⁺ , and its hydrated ion is purple-red

Titanium may be dissolved in hot nitric acid generated Ti02 ₂ · nH ₂ O
.
Zirconium can be dissolved in hot concentrated H ₂ SO ₄ or aqua regia

All titanium subgroup metals are soluble in hydrofluoric acid

Ti+6HF=H ₂ [TiF ₆ ]+2H ₂

At high temperatures, the titanium subgroup metals are very active and can be directly combined to form oxides MO ₂ , halides MX ₄ , interfilled nitrides MN, and interfilled carbides MC
.

The powdered titanium subgroup metal can absorb hydrogen and generate interfilled compounds.
The amount of hydrogen absorbed depends on temperature and pressure, and its limit composition is MH ₂

Titanium can form alloys with a variety of metals
.
When the temperature is lower than the critical temperature of 4K, the titanium-silver alloy exhibits a zero-resistance superconducting function and is the main manufacturing material for high-field superconducting magnets

Metal titanium is non-magnetic, non-toxic, biophilic (no rejection in the body), and can be used to make artificial joints and bones
.

Zirconium powder better absorption properties of the gas, can absorb oxygen, hydrogen, nitrogen, carbon monoxide and carbon dioxide, and the like
.
The alloy formed by zirconium and tin, iron, niobium and other elements has good corrosion resistance and high strength
.

Except for hydrofluoric acid , it is only soluble in concentrated sulfuric acid.
In ordinary acid and alkali media, the corrosion rate is extremely low, and it is a good corrosion-resistant material
.

Hafnium and its compounds also have the characteristics of high melting point and strong oxidation resistance, and are very good high temperature resistant materials
.

Related Links: Transitional Elements in the Living Body