Titanium metallurgy

Acetaldehyde can be used as an oxidation-promoter in place of bromine. The absence of bromine means that titanium metallurgy is not required. Eastman Chemical Co. has used such a process, with cobalt as the only catalyst metal. In that process, acetaldehyde is converted to acetic acid at the rate of 0.55—1.1 kg/kg of terephthahc acid produced. The acetic acid is recycled as the solvent and can be isolated as a by-product. Reaction temperatures can be low, 120—140°C, and residence times tend to be high, with values of two hours or more (55). Recovery of dry terephthahc acid follows steps similar to those in the Amoco process. Eastman has abandoned this process in favor of a bromine promoter (56). Another oxidation promoter which has been used is paraldehyde (57), employed by Toray Industries. This leads to the coproduction of acetic acid. 2-Butanone has been used by Mobil Chemical Co. (58). 

Materials with a low o rgen content are best subjected to a preliminary homogenization treatment, either by high-frequency heating in high vacuum, or by so-called button-melting in an electric arc, which is familiar in titanium metallurgy. 

McQuillan, A.D. McQuillan, M.A. (1956) Titanium. Metallurgy of the Rarer Metals-4 Series, Butterworths, London. 

Mar60] Margolin, H. and Nielsen, J.P., Titanium Metallurgy, in Modern Materials, Advances in Development and Application, H.H. Hausner, Ed., Vol 2, Academic Press, 1960, p. 225-325... 

Eigure 3 is a flow diagram which gives an example of the commercial practice of the Dynamit Nobel process (73). -Xylene, air, and catalyst are fed continuously to the oxidation reactor where they are joined with recycle methyl -toluate. Typically, the catalyst is a cobalt salt, but cobalt and manganese are also used in combination. Titanium or other expensive metallurgy is not required because bromine and acetic acid are not used. The oxidation reactor is maintained at 140—180°C and 500—800 kPa (5—8 atm). The heat of reaction is removed by vaporization of water and excess -xylene these are condensed, water is separated, and -xylene is returned continuously (72,74). Cooling coils can also be used (70). 

Virtually all metallurgies can be attacked by corrosive bacteria. Cases of titanium corrosion are, however, rare. Copper alloys are not immune to bacterial attack however, corrosion morphologies on copper alloys are not well defined. Tubercles on carbon steel and common cast irons sometimes contain sulfate-reducing and acid-producing bacteria. Potentially corrosive anaerobic bacteria are often present beneath... 

Because alterations to equipment design can be cumbersome and expensive, a more economical approach may be to change the metallurgy of affected components. Metals used in typical cooling water environments vary in their resistance to erosion-corrosion. Listed in approximate order of increasing resistance to erosion-corrosion, these are copper, brass, aluminum brass, cupronickel, steel, low-chromium steel, stainless steel, and titanium. 

The basic corrosion behaviour of stainless steels is dependent upon the type and quantity of alloying. Chromium is the universally present element but nickel, molybdenum, copper, nitrogen, vanadium, tungsten, titanium and niobium are also used for a variety of reasons. However, all elements can affect metallurgy, and thus mechanical and physical properties, so sometimes desirable corrosion resisting aspects may involve acceptance of less than ideal mechanical properties and vice versa. 

The carbide precipitation that leads to sensitised grain boundary regions can be minimised by reducing the carbon to 0.03% or less but this increases the cost and reduces the strength. The alternative is to add stabilising elements such as titanium or niobium, which are stronger carbide formers than chromium. There are numerous texts that describe the metallurgy of... 

Titanium. The metallurgy of titanium illustrates the purification of one metal by another. The major titanium ores are mtile (Ti02) and ilmenite (FeTi03). Either is converted to titanium(IV) chloride by a redox reaction with... 

Sulfate solubility properties are the basis for other industrial uses of sulfuric acid. One example is in the metallurgy of titanium. One of the major ores of titanium is FeTi03, which is treated with sulfuric acid to separate titanium from iron ... 

In addition to making organic chlorine compounds, a significant fraction of CI2 production is used to make inorganic halides. One important use, described in Chapter 20, is in the metallurgy of titanium, in which molecular chlorine is used to convert Ti02 into TiCl4, which is easy to purify by distillation. 

Also, according to Thellmann (Ref 16), there is an economic advantage over other fuels to the utilization of both powder metallurgy (PM) and Ti in the mfg of pyrot incendiaries.. . titanium delivers more BTU s per pound, more BTU s per cubic inch, lower cost per cubic inch, more... 

Roasting furnaces are used to react sulfides to produce metal oxides, which can be converted to metals in the next process step. The sulfides are used as a reducing agent in nonferrous metallurgy for the recovery of metals. The process has been used for metals such as copper, lead, zinc, nickel, magnesium, tin, antimony, and titanium. 

The compacted powder mixtures of these materials are usually liquid phase sintered with Ni or Ni-Co binder metal alloys. The microstracture features a core-and-rim stracture of the hard phase with a molybdenum- and carbon-rich (Ti,Mo)C rim and a titanium- and nitrogen-rich Ti(C,N) core. This microstructure can be made visible in the SEM (Figure 16). The metallurgy of the phase reactions is not... 

Of all the 115 elements listed in the Periodic Table, 70% exhibit metallic character. Since the discovery of copper and bronze by early civilizations, the study of metals i.e., metallurgy) contributed to most of the early investigations related to materials science. Whereas iron-based alloys have long been exploited for a variety of applications, there is a constant search for new metallic compositions that have increasing structural durability, but also possess sufficiently less density. The recent exploitation of titanium-based alloys results from this effort, and has resulted in very useful materials that are used for applications ranging from aircraft bodies to golf clubs. Indeed, there are many yet undiscovered metallic compositions that will undoubtedly prove invaluable for future applications. 

Shkiro, V. M., and Borovinskaya, I. R, Study of the titanium and carbon mixtures combustion. In Combustion Processes in Chemical Engineering and Metallurgy (Russ.) (A. G. Merzhanov, ed.). USSR Academy of Science, Chemogolovka, Russia, 1975, p. 253. 

Sandberg H., Influence of titanium on micro segregations in high-speed steel ingots. Scand. J. Metallurgy, 2 (1973), 233-241... 

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