Copper, solvent extraction

Figure 5.20 Bluebird mine copper solvent extraction process.

Hartlage, J. A. Kelex 100—a new reagent for copper solvent extraction. Paper presented at Society of Mineral Engineers, AIME Fall Meeting, Salt Lake City, September 1969. 

The process flow sheet was first tested for direct leaching of steel mill flue dust and production of zinc metal by electrowinning. The tests were performed in a continuously operating pilot plant, producing 10-20 kg/day zinc metal. The same pilot plant was then used for treating copper/zinc-rich brass mill flue dust in a closed loop operation, recycling all the zinc solvent extraction raffinate to the copper circuit leach section. In the zinc circuit leach section, only the amount of zinc rich dust necessary for neutralization of the copper solvent extraction raffinate was used. The results obtained from the pilot plant tests indicated contamination problems within the solvent extraction loops. The estimation of economic data showed a weak return on the assets compared with the alkali route, and sensitivity toward the raw material price. 

The copper solvent extraction raffinate is split with a portion of the raffinate returning to leaching and the balance advancing to cobalt, zinc and manganese recovery. The raffinate for cobalt, zinc and manganese recovery is first neutralized to remove iron and aluminum from solution and then subjected to a novel direct solvent extraction process (DSX) developed by CSIRO (Australia) [4-6]. The direct solvent extraction process uses a mixture of Versatic 10... 

Cognis. 2000. Operation of copper solvent extraction plants a Cognis overview. Unpublished. 

Dasher, J. and Power, K. 1971. Copper solvent-extraction process from pilot study to full-scale plant. Min. J. 172 111-115. 

Hein, H. 2005. The importance of a wash stage in copper solvent extraction. In HydroCop-per 2005, Proceedings III international copper hydrometallurgy workshop, eds. J. M. Penacho and J. Casas de Prada, 425-436. Santiago Universidad de Chile. 

House, J. E. 1989. The development of the LIX reagents. Miner. Metall. Proc. 6(2) l-6. Hurtado-Guzman, C. and Menacho, J. M. 2003. Oxime degradation chemistry in copper solvent extraction plants. In Proceedings hydrometallurgy of copper modelling, impurity control and solvent extraction, vol. 6, book 2, eds. PA. Rivieros, D. G. Dixon, D. 

Kordosky, G. A. 2003. Copper SX circuit design and operation current advances and future possibilities. In Proceedings ALTA copper 2003. Melbourne ALTA Metallurgical Services. Kordosky, G. and Vimig, M. 2003. Equilibrium modifiers in copper solvent extraction reagents friend or foe In Hydrometallurgy 2003, vol. 1, Leaching and solution purification, eds. 

Readett, D. and Townson, R. 1997. Practical aspects of copper solvent extraction from acidic leach liquors. Proceedings ALTA 1997 copper hydrometallurgy forum. Melbourne ALTA Metallurgical Services. 

Section III.A discussed how WP-1 and WP-2 could be used as metal ion chromatographic materials. Given the selectivity of CuWRAM for copper, we thought that the use of this resin in a tandem column composed of WP-2 could be used to separate more effectively this metal from other transition metals. To test this hypothesis we obtained a sample of a copper solvent extraction waste stream from a chal-cocite (Cu2S)/cobaltite (CoAsS) ore leach from a mine in the United States. The iron in the leach had been removed by precipitation before the copper solvent extraction and contained significant amoimts of copper and cobalt as well as arsenic. The goal was to separate the cobalt from the copper and to reject the arsenic. 

Figure 15 Flowthrough (A) and strip (B) resulting from successive loading of 5-mL CuWRAM and WP-2 columns with 30 mL of a raffinate form of a copper solvent extraction circuit after iron precipitation by adjustment to pH 4.

The development of the novel Davy-McKee combined mixer—settler (CMS) has been described (121). It consists of a single vessel (Fig. 13d) in which three 2ones coexist under operating conditions. A detailed description of units used for uranium recovery has been reported (122), and the units have also been studied at the laboratory scale (123). AppHcation of the Davy combined mixer electrostatically assisted settler (CMAS) to copper stripping from an organic solvent extraction solution has been reported (124). 

Fig. 18. Diagrammatic representation of copper extraction using solvent extraction (273).

Copper. Domestic mine production of copper metal in 1994 was over 1,800,000 t. Whereas U.S. copper production increased in the 1980s and 1990s, world supply declined in 1994. There are eight primary and five secondary smelters, nine electrolytic and six fire refiners, and fifteen solvent extraction—electro winning (SX—EW) plants. Almost 540,000 t/yr of old scrap copper and alloy are recycled in the United States accounting for - 24% of total U.S. consumption (11). New scrap accounted for 825,000 t of contained copper. Almost 80% of the new scrap was consumed by brass mills. The ratio of new-to-old scrap is about 60 40% representing 38% of U.S. supply. 

Metal Extraction. As with other carboxyhc acids, neodecanoic acid can be used in the solvent extraction of metal ions from aqueous solutions. Recent appHcations include the extraction of zinc from river water for deterrnination by atomic absorption spectrophotometry (105), the coextraction of metals such as nickel, cobalt, and copper with iron (106), and the recovery of copper from ammoniacal leaching solutions (107). 

Selectivity for a single metal of a group is the basis of a solvent extraction process for the recovery of copper (qv) from low concentration ore leach solutions containing high levels of iron (qv) and other interfering metals (16). 

Cementation. Cementation is the precipitation of copper from copper leach solutions by replacement with iron. It was formerly the most commonly used method of recovering copper from leach solutions but has been replaced by solvent extraction—electro winning. The type of iron used ia cementation is important, and the most widely used material is detinned, light-gauge, shredded scrap iron. This operation can be performed by the scrap iron cone (Keimecott Precipitation Cone) or a vibrating cementation mill that combines high copper precipitation efficiency and reduced iron consumption (41). 

Electrowinning. Vat leaching often yields copper solutions having concentrations sufficiently high for direct electrowinning. However, high concentrations of cations other than copper and low copper concentrations make it more difficult to obtain high purity electrolytic copper by direct electrolysis of leach solutions than by electrolysis of purified solutions obtained from solvent extraction. 

Increasingly more copper is being produced by electrowinning because of economics and technical advances, such as in solvent extraction processes. Certain brands obtained by SX—EW are treated as cathode quahty and are used directly by wire-rod manufacturers. Whereas in 1984 100,180 t of copper was electrowon in SX—EW plants, in 1992, 439,043 t produced by SX—EQ was electrowon (7). 

Eggett, G. and Naden, D. Developments in Anodes for Pure Copper Elect rowinning from Solvent Extraction Produced Electrolytes , Hydromelallurgy, Elsevier, Amsterdam, 1, 123-137 (1975)... 

Theory. Conventional anion and cation exchange resins appear to be of limited use for concentrating trace metals from saline solutions such as sea water. The introduction of chelating resins, particularly those based on iminodiacetic acid, makes it possible to concentrate trace metals from brine solutions and separate them from the major components of the solution. Thus the elements cadmium, copper, cobalt, nickel and zinc are selectively retained by the resin Chelex-100 and can be recovered subsequently for determination by atomic absorption spectrophotometry.45 To enhance the sensitivity of the AAS procedure the eluate is evaporated to dryness and the residue dissolved in 90 per cent aqueous acetone. The use of the chelating resin offers the advantage over concentration by solvent extraction that, in principle, there is no limit to the volume of sample which can be used. 

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