Parke refining

Motiva Enterprises LLC/Equilon Enterprises/Deer Park Refining (Shell) Navajo Refining Company and Montana Refining Company Sinclair Oil Co. 

In 1986 Britannia Refined Metals (Northfleet, U.K.) introduced technology for the treatment of Parkes cmst, a triple alloy of Ag, Zn, Pb, which by 1992 had been adopted by seven lead refineries (22). The technology consists of a three-stage process in which the silver-rich cmst is first Hquated to reduce its lead content, then placed in a sealed furnace where the 2inc is removed by vacuum distillation and, finally, the silver—lead metal is treated in a bottom blown oxygen cupel (BBOC) to produce a Htharge slag and dorn metal. 

Precipitation can also occur upon chemical reaction between the impurity and a precipitating agent to form a compound insoluble in the molten metal. The refining of cmde lead is an example of this process. Most copper is removed as a copper dross upon cooling of the molten metal, but the removal of the residual copper is achieved by adding sulfur to precipitate copper sulfide. The precious metals are separated by adding zinc to Hquid lead to form soHd intermetaHic compounds of zinc with gold and silver (Parkes process). The precious metals can then be recovered by further treatment (see Lead). 

Refining. The alloy of bismuth and lead from the separation procedures is treated with molten caustic soda to remove traces of such acidic elements as arsenic and teUutium (4). It is then subjected to the Parkes desilverization process to remove the silver and gold present. This process is also used to remove these elements from lead. 

The problem of the separation of zinc and lead from each other is encountered not only in the refining of zinc but also in the refining of lead. When lead is subjected to refining by the Parkes process, a certain amount of zinc, which is not insignificant, is introduced into the refined lead bullion. This zinc impurity may be removed by distillation. 

Brittania A process for removing silver from lead, operated by Brittania Refined Metals in England, using ore from the Mount Isa mine in Australia. After initial concentration by the Parkes process, and removal of the zinc by vacuum distillation, the mixture, which contains silver (70 percent), lead, and some copper is treated in a bottom blown oxygen cupel in which lead and copper are removed by the injection of oxygen through a shielded lance. 

Several refinements of our experiments could test these theories further. By measuring etch pit densities as well as pit dimensions on sequentially-etched crystals, nucleation rate data and pit growth data could be collected, yielding information about the rate-limiting steps and mechanisms of dissolution. In addition, since the critical concentration is extremely dependent on surface energy of the crystal-water interface (Equation 4), careful measurement of Ccrit yields a precise measurement of Y. Our data indicates an interfacial energy of 280 + 90 mjm- for Arkansas quartz at 300°C, which compares well with Parks value of 360 mJm for 25°C (10). Similar experiments on other minerals could provide essential surface energy data. 

Sittig, M. Petroleum Refining Industry Energy Saving and Environmental Control, Noyes Data Corp. Park Ridge, NJ, 1978. 

Several experimental techniques have been developed for the investigation of the mass transport in porous catalysts. Most of them have been employed to determine the effective diffusivities in binary gas mixtures and at isothermal conditions. In some investigations, the experimental data are treated with the more refined dusty gas model (DGM) and its modifications. The diffusion cell and gas chromatographic methods are the most widely used when investigating mass transport in porous catalysts and for the measurement of the effective diffusivities. These methods, with examples of their application in simple situations, are briefly outlined in the following discussion. A review on the methods for experimental evaluation of the effective diffusivity by Haynes [1] and a comprehensive description of the diffusion cell method by Park and Do [2] contain many useful details and additional information. 

Conference on Knowledge Discovery and Data Mining, R. Agrawal, P. Stolorz, and G. Piatetsky-Shapiro, Eds., AAAI Press, Menlo Park, CA, 1998, pp. 194-198. Initialization of Iterative Refinement Clustering Algorithms. 

Silver is often removed from lead by the Parkes process, described in Chapter 27. Some pure lead is made by electrolytic refining. 

Industrial Automation history in the Petrobras Downstream area can be traced back to 1986, when the company decided to replace old analog instrumentation by digital control systems (DCS), which, given the sheer size of the refining park, with 10 oil refineries, demanded a considerable investment. 

Method of purification Desilvering (Parkes process), electrolytic refining (Betts process), pyrome-tallurgical refining (Harris process). Bismuth is removed by Betterton-Kroll process. 

P.O. Box 431, Kingsport, Tenn. 37662 EGA-Chemie KG, Steinheim, Germany Engelhard Industries, Inc., 113 Astor St., Newark, N. J. 07114 Enjay Chemical Company, A Division of Humble Oil and Refining Co., 60 West 49th St., New York, N.Y. 10020 Ethyl Corp., 100 Park Ave., New York,... 

R. D. Kane, Corrosion in petroleum refining and petrochemical operations, in ASM Handbook, Vol. 13C, Corrosion Environments and Industries, ASM International, Materials Park, OH, 2006, pp. 992-998. 

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