Magnesium reduction

The manufacture of refractory metals such as titanium, zirconium, and hafnium by sodium reduction of their haHdes is a growing appHcation, except for titanium, which is produced principally via magnesium reduction (109—114). Typical overall haHde reactions are... 

Magnesium-Reduction (Kroll) Process. In the 1990s, nearly all sponge is produced by the magnesium reduction process (Fig. 4). 

Fig. 5. Vacuum-distilled titanium sponge produced by magnesium reduction at Teledyne Wah Chang (Albany, Oregon).

Noncarbonate or permanent calcium hardness, if present, is not affected by treatment with lime alone. If noncarbonate magnesium hardness is present in an amount greater than 70 ppm and an excess hydroxyl alkalinity of about 5 ppm is maintained, the magnesium will be reduced to about 70 ppm, but the calcium will increase in proportion to the magnesium reduction. 

To improve magnesium reduction, which also improves siHca reduction in cold process softening, sodium aluminate may be used. The sodium aluminate provides hydroxyl ion (OH ) needed for improved magnesium reduction, without increasing calcium hardness in the treated water. In addition, the hydrolysis of sodium aluminate results in the formation of aluminum hydroxide, which aids in floe formation, sludge blanket conditioning, and siHca reduction. 

Reduction. BrezeHus attempted the first reduction of zirconium in 1824 by the reaction of sodium with potassium fiuorozirconate. However, the first pure ductile metal was made in 1925 by the iodide thermal-dissociation method. The successfiil commercial production of pure ductile zirconium via the magnesium reduction of zirconium tetrachloride vapor in an inert gas atmosphere was the result of the intense research efforts of KroU and... 

In the production of metallic uranium the fluoride UF4 is used for magnesium reduction since die reduction of UCI4 does not produce sufficient heat. The chloride can be reduced with calcium, when a signihcantly greater amount of heat is generated to reach die desired temperature. 

Refractory metals Zirconium Hafnium Titanium Kroll process, chlorination, and magnesium reduction Chlorine, chlorides, SiCli Wet scrubbers... 

The magnesium reduction is used extensively in the industrial production of the metal as follows ... 

After reduction is complete, most of the magnesium chloride is mechanically separated from the reduced mass the remaining fraction is removed along with the excess magnesium reductant by vacuum distillation at about 900 °C under a pressure of 10 3 to 10-1 torr. A schematic diagram of the reactor used for vacuum distillation is shown in Figure 4.23. 

Some samples of vanadium prepared by magnesium reduction of vanadium dichloride or vanadium trichloride are pyrophoric. 

Kroll (magnesium-reduction) process manufacture of, 24 851—853 price history of, 24 861t sodium-reduction process manufacture of, 24 853... 

Kupec et al. [180] determined total sulphur in sludge by a method involving magnesium reduction in which the sample is heated with magnesium powder to convert all sulphur compounds into magnesium sulphide. The magnesium sulphide is treated with sulphuric acid and the evolved hydrogen sulphide determined by iodometric titration. 

Preparation. It is difficult to prepare very pure boron. The element can be obtained by magnesium reduction of the oxide, B203. The oxide is made by melting boric acid which in turn is obtained from borax. 

Beryllium fluoride is the intermediate compound in the magnesium-reduction process to produce beryllium metal. The compound also is used in the manufacture of glass, and in nuclear reactors. 

Dimethyl-2,3-butanediol (pinacol) (2.12) on treatment with H2SO4 generates 3,3-dimethyl-2-butanone, commonly known as pinacolone (2.13). Pinacol itself is produced by magnesium reduction of acetone, probably by way of a ketyl intermediate. 

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