Nickel slurries

To reduce labor and other expenses, most sintered nickel plaques are produced by a wet-slurry method. A nickel slurry is prepared by mixing a low density nickel powder with a viscous aqueous solution such as carboxymethylceUulose [9004-42-6] (CMC). Pure nickel gau2e, a nickel-plated gau2e, or a nickel-plated perforated steel strip is continuously carried through a container filled with the nickel paste and sintering is done in a hori2ontal furnace. The time of the sinter in the furnace is ca 10—20 min. 

Klabunde has reported limited reactivity toward oxidative addition reactions of carbon halogen bonds with nickel slurries prepared by the metal vaporization technique(65). 

The activated nickel powder is easily prepared by stirring a 1 2.3 mixture of NiL and lithium metal under argon with a catalytic amount of naphthalene (1(7 mole % based on nickel halide) at room temperature for 12 h in DME. The resulting black slurry slowly settles after stirring is stopped and the solvent can be removed via cannula if desired. Washing with fresh DME will remove the naphthalene as well as most of the lithium salts. For most of the nickel chemistry described below, these substances did not affect the reactions and hence they were not removed. The activated nickel slurries were found to undergo oxidative addition with a wide variety of aryl, vinyl, and many alkyl carbon halogen bonds. 

The reaction between metal atoms and ethers is varied. Deoxygenation occurs with the more electropositive transition metals, e.g., Ti, V, Cr, and probably Fe, but Klabunde has been able to use tetrahydrofuran as a medium to form active nickel slurries by condensing in nickel vapor (56, 60). 

A nickel slurry was prepared in the usual manner and allowed to settle. The pale beige solution above the slurry was removed, and 1 equiv of CeFsl was syringed in. The mixture was stirred at about 60°C for 19 h, after which time a deep orange-brown solution existed. The solution was allowed to cool, and 3 equiv of (C6H5)2PH was slowly syringed in. Initially the mixture became yellow and then deep green in a mildly exothermic reaction. The mixture was stirred... 

ECPSA, Cuba Wirth 10 pumps, 200 mYhr (SOOgpm), 6.4 MPa (920 psi), iron-nickel slurry... 

Bulong Nickel project—200°C laterite nickel slurry (Australia)... 

Catalytic methanation processes include (/) fixed or fluidized catalyst-bed reactors where temperature rise is controlled by heat exchange or by direct cooling using product gas recycle (2) through wall-cooled reactor where temperature is controlled by heat removal through the walls of catalyst-filled tubes (J) tube-wall reactors where a nickel—aluminum alloy is flame-sprayed and treated to form a Raney-nickel catalyst bonded to the reactor tube heat-exchange surface and (4) slurry or Hquid-phase (oil) methanation. 

Direct l eaching of Concentrates. Sherri tt Gordon Mines, Ltd., has adapted the process first used on nickel sulfide ores to zinc sulfide oxidation with air in aqueous slurry under pressure (42,43). The concentrates are leached direcdy with return acid from the cells and the sulfide is converted to free sulfur ... 

Nickel—2iiic batteries containing a vibrating zinc anode lias been reported (83). In this system zinc oxide active material is added to the electrol 1 e as a slurry. During charge the anode substrates are vibrated and the zinc is electroplated onto the surface in a unifomi mamier. Tlie stationary positive electrodes (nickel) are encased in a thin, open plastic netting which constitutes the entire separator system. 

The effect of physical processes on reactor performance is more complex than for two-phase systems because both gas-liquid and liquid-solid interphase transport effects may be coupled with the intrinsic rate. The most common types of three-phase reactors are the slurry and trickle-bed reactors. These have found wide applications in the petroleum industry. A slurry reactor is a multi-phase flow reactor in which the reactant gas is bubbled through a solution containing solid catalyst particles. The reactor may operate continuously as a steady flow system with respect to both gas and liquid phases. Alternatively, a fixed charge of liquid is initially added to the stirred vessel, and the gas is continuously added such that the reactor is batch with respect to the liquid phase. This method is used in some hydrogenation reactions such as hydrogenation of oils in a slurry of nickel catalyst particles. Figure 4-15 shows a slurry-type reactor used for polymerization of ethylene in a sluiTy of solid catalyst particles in a solvent of cyclohexane. 

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