Metal , recovery from mine solutions

Reverse osmosis also serves some of the waste management and resource recovery needs in the metals and metal finishing industry. Effluent streams from mining and plating operations containing heavy metals, acids, and other chemicals can be treated with reverse osmosis to recover both the metal as its salt, and purified water for reuse. For metal ion recovery from dilute solutions, however, reverse osmosis faces competition from conventional solvent extraction, membrane-based solvent extraction, and its variant, coupled transport (see Section V.F.3). 

Hydrometallurigcal Processes. In hydrometaHurgical processes, metal values and by-products are recovered from aqueous solution by chemical or electrolytic processes. Values are solubilized by treating waste, ore, or concentrates. Leaching of copper ores in place by rain or natural streams and the subsequent recovery of copper from mnoff mine water as impure cement copper have been practiced since Roman times. Most hydrometaHurgical treatments have been appHed to ores or overburden in which the copper was present as oxide, mixed oxide—sulfide, or native copper. PyrometaHurgical and hydrometaHurgical processes are compared in Reference 34. 

The high tension ion conduction agglomeration (INCA) system is an ex situ process for the recovery of soluble and particulate metals from aqueous solutions such as mining effluents, process waters, and wastewater. It is not known if the technology is currently commercially available. 

The recovery of the metal values from sources other than freshly mined ores is gaining a lot of interest, Old mine workings are further exploited for their metal values by flooding of the underground workings with leach solutions and recovering the metal by conventional separation processes. Copper and uranium have been recovered in this way. The mine waste... 

The waste streams in standard metallurgical processing are good potential sources of important elements. The U.S. Bureau of Mines has developed processes for the recovery of elemental sulfur from stack gases discharged by base metal smelters (G4) and for the recovery and production of alumina from waste solutions of mining operations (G6). A potential of 1,750,000 tons of sulfur per year and an estimated 2000 tons of alumina per day are recoverable just from 14 copper mines included in the study. 

Recovery of valuable metals from secondary sources. At the present state of development the more promising metal recovery processes based on SIR systems appear to be in the following applications in terms of both process performance and economic considerations (a) Recovery of metals from dilute solutions, particularly where such solutions are available at low cost (e.g., waste solution from other processes, mine waters, or dump leaching solutions) (b) separation of metals from concentrated solutions obtained by hydrometallurgical processing of complex ores, concentrates, mattes, and scraps and purification of process solutions (such as electrolytes) which may contain a variety of metals that have been only partially recovered in the conventional processing steps (c) separation and purification of met-... 

Even not recognized as such, the galvanic displacement deposition of noble metals such as Au or Ag onto Fe, Zn, Cu, or similar substrates is known since the times of early Mediterranean cultures and, possibly, before. In the sixteenth century, the recovery of copper from copper mine waters by contacting dilute process streams with iron scrap was successfully achieved [2]. Since that time, many different galvanic displacement deposition processes have been developed. Examples used on industrial scale include application of aluminum, iron, or zinc powders for the removal of copper, silver, gold, or other noble metals from waste solutions. Similar approaches are used for the solution purification in hydrometallurgical plants, electronics, electrochemical experiments, etc. 

D. Kratochvil, Plant Commissioning in China for Ni-Co Recovery from Low Grade Waste Solution in Recycling Metals from Industrial Waste, Colorado School of Mines, Golden, June 2011. 

The first commercial reagents were aU based on ketoxime functionality and were used exclusively for copper extraction for over a decade after the first full-scale application at Bluebird Ranchers Mine, Arizona, in 1968 (Arbiter and Fletcher 1994). Today, ketoximes are still successfully used in niche applications for the recovery of copper from dilute leach liquors and also find applications in nickel SX from ammoniacal solutions and in precious metal refining (see Sections S.3.3.3 and 5.3.6.2). Particular applications of ketoximes in copper production are at El Tesoro and Lomas Bayas in the Atacama Desert of Chile, where the leach liquors of circuits often contain high... 

Table 1 gives the average metal content of the earth s cmst, ore deposits, and concentrates. With the exceptions of the recovery of magnesium from seawater and alkaU metals from brines, and the solution mining and dump or heap leaching of some copper, gold, and uranium (see Uranium and uranium compounds), most ores are processed through mills. Concentrates are the raw materials for the extraction of primary metals. 

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