Vacuum degassing

HBI is an effective trim coolant for molten steel in ladle metallurgy faciUties, ladle refiners, ladle furnaces, and vacuum degassers. It provides cold iron units in an ideal size and density for penetrating the ladle slag and cooling the metal. 

Ladle metallurgy, the treatment of Hquid steel in the ladle, is a field in which several new processes, or new combinations of old processes, continue to be developed (19,20). The objectives often include one or more of the following on a given heat more efficient methods for alloy additions and control of final chemistry improved temperature and composition homogenisation inclusion flotation desulfurization and dephosphorization sulfide and oxide shape control and vacuum degassing, especially for hydrogen and carbon monoxide to make interstitial-free (IF) steels. Electric arcs are normally used to raise the temperature of the Hquid metal (ladle arc furnace). 

R. J. Fmehan, Vacuum Degassing, Iron and Steel Society, Warrendale, Pa., 1990. 

The heart of these couplings is the flexing disc it is manufactured from vacuum-degassed alloy steel, forged with a radial-grain orientation, and has a contoured profile machined on high-precision equipment. 

Oxidant Removal The presence of oxidizers such as chlorine or ozone can degrade polyamide RO membranes, causing a drop in salt retention. Cellulosic membranes are less sensitive to attack. Addition of 1.5 to 6 mg sodium bisulfite/ppm chlorine or contacting with activated carbon will remove oxidizers. Vacuum degassing with a hydrophobic filter module is also used. 

The simple tank discharge problem of Sec. 1.2.3.1 has been extended by Szekely and Themelis (1971) to cover the discharge of molten steel from a ladle into a vacuum degassing chamber the transfer being effected via a discharge nozzle, in which the effects of both friction and wear can be important. 

Energy use per ton of Largest source teeming Sources vacuum degassing, Mill scale, sludge... 

This process involves the reaction of dried rutile ore and coke with chlorine in the chlorinator to produce titanium tetrachloride. The liquefied titanium tetrachloride is sent to the distillation unit to remove impurities and then to a fluidized bed reactor to react with oxygen to form titanium dioxide and chlorine. Solid titanium dioxide formed at this stage is vacuum degassed before being treated... 

Very unstable, it decomposes explosively during vacuum degassing. 

Of the three general methods, the last seems to be the most practical. Theoretically, with high enough concentrations of hydrocarbons, the first method, the headspace analysis, should be both the most accurate and the easiest to calibrate. Operationally, it leaves much to be desired both because of the problems of sensitivity and those of the accommodation of the larger molecules in water. The second method, vacuum degassing, requires much more equipment than the third method and requires that large amounts of water vapor be removed before the sample is injected into the gas chromatograph. The last method is so much less complicated that even with its calibration problems it has been adopted almost universally. 

Dortmund-Hoerder Also called DH. A steelmaking process in which the molten metal is vacuum degassed. 

FIGURE 8 A schematic of a 4-solvent on-line vacuum degasser. The preferred device for solvent degassing. 

Turn on the on-line vacuum degasser and the seal wash pump system (if available). 

Perform a wet prime for all lines when changing the solvent reservoirs. Note that many older vacuum degassers have an internal volume of lOmL or more and must be purged out with the new... 

On-line vacuum degasser and seal wash system—inspect and check functions. 

Furthermore, the solubility of gases in liquids decreases with rising temperature. Accordingly, the concentration of a dissolved gas in water can be reduced simply by vacuum degassing or by heating. Alternatively, one can resort to specific chemical methods of removal.18,19... 

Oxygen is soluble in water to the extent of 9.4 ppm from air at 100 kPa and 20 °C, and 02 is the oxidant responsible for most metallic corrosion. Consequently, deaeration of water by purging with nitrogen or vacuum degassing may be desirable in some circumstances this should not be undertaken without circumspection, since deoxygenation may cause activation of otherwise passive metals or cause cathodic areas to become anodic (Chapter 16). At high temperatures, aqueous oxygen is consumed quite rapidly by hydrazine or sodium sulfite (Section 16.7). 

The HPLC system consist of an HP 1100 series binary gradient pump, a vacuum degasser, and a column temperature controller (all from Hewlett Packard), connected to a Gilson 231 XL autosampler (Gilson). 

Vacuum degassing AU-fiber Vacuum degassing AS-fiber... 

Caution. Vacuum degassing of Sephadex gel may produce violent evolution of gas. A safety shield should surround the evacuated flask. 

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