64 metal prodnced

Fosbel [Foseco Belret] A ceramic welding process for repairing refractories. A dry mixture of a refractory and a metallic powder is projected, in a stream of oxygen, onto the snr-face to be repaired. Oxidation of the metal prodnces the necessary high temperatnre. Developed by Foseco, UK, and Belret, Belginm, hence the name. 

Since the heavier transition metals prodnce larger splitting of the d orbitals than their 3d congeners [i.e., they occupy systematically higher positions in the spectrochemical series of the metals, (1)] and also present lower pairing energies, the low-spin states are favored for 4d and 5d metals, specially when combined with high oxidation states. Hence, well-characterized low-spin tetrahedral d, d", and d complexes of the type [MR4] are known for Re(IV), Ru(IV), Os(IV), Ir(V), and Ir(IV). 

All methods of welding stainless steel with a filler metal prodnce a weld fnsion bonndary consisting of base metal that has been melted, but not mechanically mixed with filler metal and a partially melted zone in the base metal. The weld fusion boundary lies between a weld composite consisting of filler metal diluted by base metal and the HAZ in the base metal. The width of the unmixed zone depends on the local thermal conditions along the weld fusion line. For a GTA welding process, the zone is most narrow at the weld face and is broadest near the middle of the weld thickness. 

A black finish on a metal prodnced by immersing it in hot oxidizing salts or salt solutions. 

These primary electrochemical steps may take place at values of potential below the eqnilibrinm potential of the basic reaction. Thns, in a solntion not yet satnrated with dissolved hydrogen, hydrogen molecnles can form even at potentials more positive than the eqnilibrinm potential of the hydrogen electrode at 1 atm of hydrogen pressnre. Becanse of their energy of chemical interaction with the snbstrate, metal adatoms can be prodnced cathodically even at potentials more positive than the eqnilibrinm potential of a given metal-electrolyte system. This process is called the underpotential deposition of metals. 

The nnclei and the elements of new phase generated from them (gas babbles, metal crystallites) are macroscopic entities their nnmber on the surface is limited (i.e., they emerge not at all surface sites but only at a limited number of these sites). Hence, the primary products should move (by bulk or surface diffusion) from where they had been prodnced to where a nucleus appears or grows. 

The concept of bifnnctionality can be snitably expanded (Scheme 1) to prodnce multifunctional catalysts bearing both diverse nanostructured metals and diverse chemical functionalities for performing complementary catalytic tasks. 

The Unipnre Environmental, Unipnre process technology is a unique iron co-precipitation method for removal of heavy metals from waste streams or groundwater. It can act as a primary metal-removal system or as a polishing step to an existing treatment system. The reactor mod-nle replaces the nentrahzation tank in a conventional wastewater treatment system. The process prodnces solids that are extremely insolnble in water and mild acid solutions. 

In 1986, domestic consumption of copper in the United States was 2.14 million metric tons, and mine prodnction was 1.14 million metric tons, mostly from mines in Arizona, New Mexico, and Michigan. The major copper deposits in the United States are of hydrothermal origin and are uniformly distribnted in fractnres or veins (ATSDR 1990). Copper is the major toxic component in streams impacted by active placer mines (Bnhl and Hamilton 1990). About 60% of copper metal is eventually recycled in 1986, smelting of scrap copper prodnced an additional 0.9 million metric tons of copper. Also in 1986, 1.1 million tons of copper were imported into the United States, mostly from Canada, Chile, Pern, and Mexico (ATSDR 1990). 

In 1973, global consnmption of nickel was 660,000 tons and that of the United States 235,000 tons (Sevin 1980). End nses of nickel in the United States in 1973 were transportation (21%), chemicals (15%), electrical goods (13%), fabricated metal prodncts (10%), petroleum (9%), construction (9%), machinery (7%), and honsehold appliances (7% lARC 1976). A similar pattern was evident for 1985 (Table 6.3). In 1988, 40% of all nickel intermediate prodncts consnmed was in the production of steel 21% was in alloys, 17% in electroplating, and 12% in snper alloys (USPHS 1993). The pattern for 1985 was similar (Table 6.3). In Canada, nickel is the fonrth most important mineral commodity behind copper, zinc, and gold. In 1990, Canada prodnced 197,000 tons of nickel worth 2.02 billion dollars and was the second largest global producer of that metal (Chau and KuUkovsky-Cordeiro 1995). Most of the nickel used in the United States is imported from Canada and secondarily from Australia and New Caledonia (USPHS 1977). 

The limited data on the photostability of metal-tin complexes snggest that a process similar to that occurring in the thermal decompositions can take place. For example, RHgSnMe3 (R = Me, Et, Pr, i-Pr, t-Bn) complexes prodnce ditin componnds via a radical process and Hg(SnR3)2 (R = Me, Et, Bn, Ph, CH2C(Bn-t)3, f-Bn) exhibit a stability proportional to the bnlk of the organic radical snbstitnent . ... 

Electrolysis reactions use direct current to prodnce redox reactions. Production of very active elemental metals and very active elemental nonmetals is often done using electrolysis. The conditions under which an electrolysis is carried ont often make a great deal of difference as to which prodncts are obtained. (Section 17.4)... 

Although beryllium metal is rather sluggishly reactive toward most organic halides, it reacts surprisingly easily with acyl halides in ethyl acetate to form acylberyUium halides. These react normally with ketones by addition, prodncing hydroxy ketones. With aromatic ketones, electron transfer appears to dominate, as the principal prodnct from the ketone is the pinacol. 

Boric oxides, boric acids, and metal borates are of primary importance in any discnssion of boron chemistry since these inclnde essentially all boron minerals and the vast majority of boron componnds prodnced and nsed worldwide on a weight basis. Reviews of this chemistry and the commercial aspects of this general snbject are available. hs... 

Silica-supported Ta hydride (=SiO)2Ta-H (93a) presents unusual properties in the activation of alkanes. It catalyzes the metathesis reaction of alkanes to give higher and lower molecular weight alkanes, and the hydrogenolysis of alkanes such as ethane to methane. This hydride also activates the C H bonds of cycloalkanes to form the corresponding surface metal-cycloaUcyl complexes, and catalyses the H/D exchange reaction between CH4 and CD4, prodncing the statistical distribution of methane isotopomers. ... 

If HCl is available cheaply, aimnoninm chloride can also be prodnced from ammonia and HCl. Armnoninm chloride as gas, solid, or in solntion is corrosive becanse it is acidic, it complexes metal ions and it contains the corrosive chloride ion. 

Although the activation of hydrogen peroxide by reduced transition metals has been known for almost 100 years as Fenton chemistry (eqnations 74-77) there is nncertainty as to whether this chemistry prodnces free hydroxyl radicals (HO-). There is clear kinetic evidence that free HO- is not the dominant reactive intermediate in Fenton chemistry, bnt rather an HOOH/Fe L addnct that resnlts from nncleophilic addition. ... 

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