Molybdenum content

Carbon content is usually about 0.15% but may be higher in bolting steels and hot-work die steels. Molybdenum content is usually between 0.5 and 1.5% it increases creep—mpture strength and prevents temper embrittlement at the higher chromium contents. In the modified steels, siUcon is added to improve oxidation resistance, titanium and vanadium to stabilize the carbides to higher temperatures, and nickel to reduce notch sensitivity. Most of the chromium—molybdenum steels are used in the aimealed or in the normalized and tempered condition some of the modified grades have better properties in the quench and tempered condition. 

Analytical Methods. Molybdenum contents in ore concentrates and technical oxide are most accurately deterrnined gravimetricaHy by precipitating lead molybdate. Molybdenum content is usually not determined on pure compounds or metal. Instead, spectrographic methods are used to measure impurity elements that must be controlled. Carbon and oxygen in metal products are measured by standard gas analysis methods. 

Another set of nickel aHoys, which have a high chromium content, a moderate molybdenum content, and some copper, are the ILLIUM aHoys. These cast aHoys are wear and erosion resistant and highly resistant to corrosion by acids and alkaHes under both oxidizing and reducing conditions. 

These alloys have extensive applications in sulfuric acid systems. Because of their increased nickefand molybdenum contents they are more tolerant of chloride-ion contamination than standard stainless steels. The nickel content decreases the risk of stress-corrosion cracking molybdenum improves resistance to crevice corrosion and pitting. 

The addition of a minimum of 2% molybdenum content in type 316 stainless steel has been shown to reduce the tendency for pitting-type corrosion in chloride environments. Hoar and Mears postulated that chloride ions accelerate the corrosion of stainless steel by penetrating the oxide him. The chloride-contaminated him then loses its passivating quality and a local attack on the metal follows, creating a pit. The exact mechanism by which molybdenum strengthens the oxide him is not clearly understood. ... 

Table 3.21B Effect of molybdenum content on atmospheric corrosion. Heavy industrial site. ...

The molybdenum cofactor was liberated from D. gigas AOR, and under appropriate conditions was transferred quantitatively to nitrate reductase in extracts of Neurospora crassa nit-1 mutant) to yield active nitrate reductase 217). On the basis of molybdenum content, the activity observed for reconstitution with molybdenum cofactor of D. gigas was lower (25%) than the values observed for the procedure using extractable molybdenum cofactor of XO, used as reference. This result can now be put in the context of the difference in pterin present (MPT-XO and MCD-AOR) 218). 

Replacing some of the nickel with iron produces a family of alltws with intermediate corrosion resistance between stainless steels and the Ni-Cr-Mo alloys. Alloys such as Incoloy 825 and Hastelloy G-3 and G-30 are in this family. Incoloy 825 has 40 percent Ni, 21 percent Cr, 3 percent Mo, and 2.25 percent Cu. Hastelloy G-3 contains 44 percent Ni, 22 percent Cr, 6.5 percent Mo, and 0.05 percent C maximum. These alloys have extensive applications in sulfuric acid systems. Because of their increased nickel and molybdenum contents they are more tolerant of chloride-ion contamination than are standard stainless steels. The nickel content decreases the risk of stress-corrosion cracking molybdenum improves resistance to crevice corrosion and pitting. Many of the nickel-based alloys are proprietary and are coverecf by the following specifications ... 

Primary Mined particularly for the molybdenum contained in the ores. In some instances, molybdenum could be the only valuable metal recovered from the ore. The Questa deposit in New Mexico is mined exclusively for molybdenum content. In other deposits molybdenum may be the main product recovered together with one or more products. In these deposits the molybdenum content alone would allow for a profitable operation. The ore at the Climax mine in Colorado is of this type. Currently, monazite, pyrite, tin, and tungsten are recovered from the ore none of these by-products exists singly nor together in sufficient quantity so that the ore could be mined profitably merely for the extraction of one or all of these by-products. 

Ward, J.V. 1973. Molybdenum concentrations in tissues of rainbow trout (Salmo gairdneri) and kokanee salmon (Oncorhynchus nerka) from waters differing widely in molybdenum content. Jour. Fish. Res. Board Canada 30 841-842. 

Rhenium content of molybdenite from porphyry deposits varies widely and appears to be inversely related to the molybdenum content (Fig. 1). Molybdenites from porphyry Cu-Au deposits have the highest Re contents, typically on the order of thousands of ppm Re and ranging as high as 8170 ppm Re (Mitchell) and 4609 ppm Re (Kemess South). Re-in-... 

Elemental composition Mo 59.94%, S 40.06%. The compound or mineral molybdenite may be identified nondestructively by x-ray and from physical properties. Molybdenum content of the material may be determined by various instrumental techniques after digestion of the solid in concentrated HNO3 or aqua regia followed by appropriate dilution of acid extract (See Molybdenum.)... 

Elemental composition Mo 74.99%, 0 25.01%. Molybdenum oxide is identified by x-ray crystallography. Molybdenum content in the oxide can be determined by AA, ICP, or x-ray fluorescence analysis. 

Elemental composition Mo 66.66%, 0 33.34%. Molybdenum(Vl) oxide may be identified from its physical and chemical properties and by x-ray analysis. Molybdenum content in the oxide can be measured by various instrumental techniques (see Molybdenum). 

Elemental composition Mo 35.12%, Cl 64.88%. Molybdenum pentachloride may be identified from its physical properties and the products it forms in various reactions. The molybdenum content may be measured by flame or fur-nace-AA or ICP/AES measurement following digestion with nitric acid and appropriate dilution. 

Figure 2. Dependence of molybdenum content ( ) and impregnation pH of AHM for the 0.8 Mo nm-2 catalyst (O) on the integrated intensity of the band at ca. 1710 cm-1 of NO chemisorbed on prereduced catalyts...

Figure 4. Influence of molybdenum content on methane conversion (circles) and formaldehyde selectivity (rhombus) at 873 K, a contact time of 3 sec and CH4 02 molar ratio of 11. Filled symbols for reactor 1 and open symbols for reactor 2.

Figure 2. Partial phase diagram for the Ti/Mo system over the temperature range —100°-900°C molybdenum contents from 0 to 70 atom %. (X,0) Ref. 54. ( ) Ref. 55.

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