Precious metals refinery

Trace Rhodium Recovery from Product or Byproduct Streams. As will be discussed later, there are what might be viewed as the ultimate rhodium recovery methods in which the organic matrix is burned, the rhodium recovered as an ash, then processed through a precious metal refinery before conversion into a catalyst precursor. Once rhodium is processed into an ash, there is significance expense associated with its conversion to a suitable catalyst precursor. Therefore, technologies which permit capture and reuse or reactivation and reuse are strongly preferred over more extreme procedures. 

Barbosa VL, Tandlich R, Burgess JE. Bioremediation of trace organic compounds found in precious metals refineries wastewaters A review of potential options. Che-mosphere 68 2007 1195-1203. 

Dobson, R. S., Burgess, J. E. (2007). Biological treatment of precious metal refinery wastewater A review. Minerals Engineering 20 519-532. 

Cullen MR, KominskyJR, Rossman MD, Cher-NiACK MG, Rankin JA, Balmes JR, Kern JA, Daniels RP, Palmer L, Naegel GP, et al. (1987) Chronic beryllium disease in a precious metal refinery. Clinical epidemiologic and immunologic evidence for continuing risk from exposure to low level beryllium fume. Am Rev Respir Dis 135 201 -208. 

Bakee DB, Gann PH, Brooks SM, Galiaghee J and Beenstein IL (1990) Cross-sectional study of platinum salts sensitisation among precious metals refinery workers. Am J Indust Med 18 653-664. 

The Parkes crust is liquated in four cast iron kettles at 650°C, utilising the miscibility gap in the Ag-Zn-Pb system. The upgraded alloy, which contains roximately 25% Ag, 10% Pb and 65% Zn, is tapped into 350 kg moulds and is delivered to the precious metals refinery. Low-grade alloy fix>m the liquation process is returned to the first stage desilverising pan. 

The main advantages of these nnits are their very fast kinetics and very low solution hold-up. The latter feature provides distinct benefits for systems in which low organic inventories are required, such as precious metal refineries. Centrifugal contactors are also widely used in the nnclear processing indnstry. They are not appropriate for systems in which long residence times are reqnired or for low flow rates. 

Barnes, J. E. and Edwards, J. D. 1982. Solvent extraction at Inco s Acton precious metal refinery. Chem. Ind. (5) 151-155. 

Selenium occurs in the slimes as intermetallic compounds such as copper silver selenide [12040-91 -4], CuAgSe disilver selenide [1302-09-6], Ag2Se and Cu2 Se [20405-64-5], where x < 1. The primary purpose of slimes treatment is the recovery of the precious metals gold, silver, platinum, palladium, and rhodium. The recovery of selenium is a secondary concern. Because of the complexity and variabiUty of slimes composition throughout the world, a number of processes have been developed to recover both the precious metals and selenium. More recently, the emphasis has switched to the development of processes which result in early recovery of the higher value precious metals. Selenium and tellurium are released in the later stages. Processes in use at the primary copper refineries are described in detail elsewhere (25—44). 

J. E. Hoffmann, "Recovery of Selenium from Electrolytic Copper Refinery Slimes," in V. Kudryk, D. A. Corrigan, and W. W. Liang, eds.. Precious Metals Mining Extraction and Processing H, TMS, Warrendale, Pa., 1983. 

Most commercial tellurium is recovered from electrolytic copper refinery slimes (8—16). The tellurium content of slimes can range from a trace up to 10% (see Seleniumand selenium compounds). Most of the original processes developed for the recovery of metals of value from slimes resulted in tellurium being the last and least important metal produced. In recent years, many refineries have changed their slimes treatment processes for faster recovery of precious metals (17,18). The new processes have in common the need to remove the copper in slimes by autoclave leaching to low levels (<1%). In addition, this autoclave pretreatment dissolves a large amount of the tellurium, and the separation of the tellurium and copper from the solution which then follows places tellurium recovery at the beginning of the slimes treatment process. 

The mud or slime is coUected from the bottom of the electrolytic ceUs and pumped to the sUver refinery, where it is processed for recovery of copper, precious metals, selenium, and, in many cases, teUurium. The anode slime contains 2—20% selenium as copper and sUver selenides, whereas gold exists as the metal and in combination with teUurium. A flow diagram is shown in Figure 8. 

Miscellaneous Refinery catalyst regenerator Municipal incinerators Apartment incinerators Spray drying Precious metal refining... 

Hybinette A process for extracting nickel from sulfide ores. The nickel ore that occurs in Canada is a mixture of the sulfides of nickel, copper, and iron. Several methods have been used to separate these metals. In the Hybinette process, the ore is first smelted in a blast furnace, yielding a nickel-copper matte (i.e., a mixture of their lower sulfides). This is roasted to remove sulfur and leached with dilute sulfuric acid to remove copper. The resulting crude nickel oxide is used as the anode of an electrochemical cell. The nickel deposits on the cathode, which is contained in a cloth bag. Precious metals collect in the anode slime. The process was invented by N. V Hybinette in 1904 and operated at the Kristiansand refinery, Norway, from 1910. 

To overcome some of these problems and to produce a flow sheet that could accept a wide range of feed materials, the major refining companies embarked on research programs that could replace the traditional routes. These have led to the production of three overall flow sheets that reflect the chemical complexity of these elements and the difference in the raw material feed to the different refineries. To understand these schemes, it is necessary to outline some of the fundamental chemistry of the precious metals. 

The ELM pertraction technology has good potential for more applications at industrial scale in the near future. The industries in question might include metal mining and refinery operations (precious metals and platinum group metals are good examples), tannery industry (recovery of hexavalent chromium), and processing of nuclear wastes (recovery of uranium, strontium, and other metals). 

Metallic mercury volatilizes to mercury vapor at ambient air temperatures and as a result is the most likely means by which a worker can be exposed. Mercury can be found in the ore that contains gold and silver. The process of recovering the precious metals from the ore concentrates mercury, and as a result, the potential for miner exposure to mercury can occur throughout the concentration and refinery process. Concentrating the precious metals will also concentrate mercmy by a factor of 3,000 to 4,000 (Marsdenet al. 1992). 

---