The wide application of titanium metal in the chlor-alkali industry

Titanium titaniumcn is a strong passivation tendency of metal,
In the air and oxidizing or neutral aqueous solution that can quickly generate a stable layer of oxidation protective film, even if for some reason the membrane damage, also can rapid automatic recovery.So titanium in oxidizing, neutral medium has excellent corrosion resistance.Due to the large titanium passivation performance, in many cases, when in contact with dissimilar metal does not accelerate the corrosion, which may accelerate the corrosion of dissimilar metals.As in low concentration of oxidizing acid, if the Pb, Sn, Cu or monel alloy and titanium contact form a galvanic couple, the material corrosion is accelerated, and titanium are not affected.Mild steel in hydrochloric acid, titanium and contact, because of the new hydrogen titanium surface, destroyed the titanium oxide film, not only cause the hydrogen embrittlement of titanium, and accelerate the corrosion of titanium, this may be due to titanium for hydrogen is highly active.Iron content of titanium for some medium corrosion resistance, besides the reason of raw materials, and the reason for the increase of iron is often the infiltration of iron contamination during welding bead, increase local iron content in the weld bead, the corrosion is the nature of the uneven.When using titanium iron support equipment, titanium iron iron contamination on the surface of the contact is almost inevitable in iron contamination area corrosion speed up, particularly in the presence of hydrogen.When the contamination on the surface of titanium oxide film mechanical damage occurs, hydrogen is seeping into the metal, according to the condition such as temperature, pressure, hydrogen corresponding diffusion occurs, this make the titanium produces hydrogen embrittlement of different level.So titanium in the medium temperature and medium pressure and hydrogen systems in use to avoid iron surface pollution.In general, titanium pitting corrosion will not occur.Titanium has corrosion fatigue stability.Crevice corrosion resistance of titanium is better, especially Mo Ti - 0.3-0.8 Ni and Ti - 0.2 - Pd alloy, so Mo Ti - 0.3-0.3 Ni and Ti - 0.2 - Pd alloy are widely used for sealing surface material of container equipment, to solve the problem of equipment seal face crevice corrosion.
The application of titanium due to the excellent corrosion resistance of titanium, titanium is widely used in petroleum, chemical, salt,;Pharmacy, metallurgy, electronics, aviation, aerospace, Marine and other related fields.Titanium for most salt solution has good excellent corrosion resistance, such as titanium in chloride solution than high chromium nickel steel corrosion, pitting corrosion phenomenon.But the corrosion rate is higher in the aluminium trichloride, the associated with aluminium chloride hydrolysis to produce concentrated hydrochloric acid.Titanium to heat the concentration of sodium chlorite and various hypochlorite has good stability.So titanium is widely used in vacuum salt making industry and of bleaching powder.Titanium for the majority of the alkaline solution with good corrosion resistance.Concentration of titanium in less than 50% of sodium hydroxide and potassium hydroxide solution is relatively stable.If the alkaline solution containing chloride ion or chloride, its corrosion resistance than nickel and zirconium.But under the condition of the temperature and the concentration increased, the corrosion will increase.Chlor-alkali industry * now the biggest civil titanium application fields.
Titanium is not corrosion resistant in the dry chlorine, at the same time there is a risk of fire, but has a high stability in the wet chlorine, than zirconium, hartz alloy C and monel alloy, even in a saturated chlorine medium such as sulfuric acid, hydrochloric acid and chloride also stable.
So the titanium is sulfuric acid method of choice for titanium white production of key equipment materials.Due to the corrosion resistance of titanium in hydrocarbon is very good, even when acid and chloride impurities is very good also.Therefore, titanium is widely used in organic chemical industry, such as the PTA (purified terephthalic acid (PTA)), PVA (vinylon), etc.