Solvent-extraction flowsheets

Figure 5.14 Generalized solvent extraction process flowsheet.

The present description pertaining to copper refers to solvent extraction of copper at the Bluebird Mine, Miami. When the plant became operational in the first quarter of 1968 it used L1X 64, but L1X 64N was introduced in to its operation from late 1968. The ore consists of the oxidized minerals, chrysocolla and lesser amounts of azurite and malachite. A heap leaching process is adopted for this copper resource. Heap-leached copper solution is subjected to solvent extraction operation, the extractant being a solution of 7-8% L1X 64N incorporated in kerosene diluent. The extraction process flowsheet is shown in Figure 5.20. The extraction equilibrium diagram portrayed in Figure 5.21 (A) shows the condi-... 

Commercial-scale application of solvents coming under the category of neutral reagents is largely found as applied to the nuclear industry materials, as in example, for the separation and refining of uranium, plutonium, thorium, zirconium, and niobium. A process flowsheet for extracting niobium and tantalum from various resources is shown in Figure 5.23. It will... 

T. K. Mukherjee and C. K. Gupta, Flowsheets Development for Recovery of Nonferrous Metal values from Secondary Resources by Solvent Extraction, Proceed, of a Symposium - Emerging Separation Technologies for Metals II Sponsored by the Engineers Foundation Conference and the National Science Foundation held at Kona, Hawaii, June 16-21,1996. 

Figure 5 A simplified flowsheet and materials balance for the recovery of copper from oxidic and transition ores by heap leaching, solvent extraction and electrowinning.

Figure 10 A typical solvent extraction flowsheet for PGM refining.290,291...

Nogueira, C. A. Delmas, F. New flowsheet for the recovery of cadmium, cobalt and nickel from spent Ni-Cd batteries by solvent extraction. Hydrometallurgy 1999, 52, 267-287. 

The second part deals with applications of solvent extraction in industry, and begins with a general chapter (Chapter 7) that involves both equipment, flowsheet development, economic factors, and environmental aspects. Chapter 8 is concerned with fundamental engineering concepts for multistage extraction. Chapter 9 describes contactor design. It is followed by the industrial extraction of organic and biochemical compounds for purification and pharmaceutical uses (Chapter 10), recovery of metals for industrial production (Chapter 11), applications in the nuclear fuel cycle (Chapter 12), and recycling or waste treatment (Chapter 14). Analytical applications are briefly summarized in Chapter 13. The last chapters, Chapters 15 and 16, describe some newer developments in which the principle of solvent extraction has or may come into use, and theoretical developments. 

On the modem plants employing the Bufflex flowsheet, uranyl sulfate is stripped from the resins with the bisulfate anion. The eluate contains about 1 M sulfuric acid since this is the optimum concentration for the subsequent solvent-extraction process at lower acid concentrations, the tertiary amine in solvent extraction is only partially ionized, which reduces its capacity for uranyl sulfate, whereas at higher acid concentrations the bisulfate anion begins to compete with the uranyl sulfate anion for tertiary amine functional groups. 

Many variants of the Purex (Plutonium Uranium Reduction Extraction) process23S based on TBP extraction have been developed but a basic outline flowsheet is illustrated in Figure 38. This shows the so-called early split flowsheet most commonly used in existing plants. It involves the separation of the uranium and plutonium using two different back-extractant streams during the first solvent extraction cycle. Additional solvent extraction cycles are then carried out independently on the uranium and plutonium streams to effect further purification. An alternative arrangement is the iate split flowsheet used at the Cap La Hague plant in France, and the... 

Windscale II plant in the UK. In this the uranium and plutonium are back-extracted together in a first cycle of decontamination. They are then separated in a second cycle of solvent extraction and independent back-extraction. The factors affecting the choice of flowsheet type have been reviewed and criticality control is an important consideration in the process design.286... 

Birkett, J.E., Carrott, M.J., Fox, O.D. et al. 2007. Controlling neptunium and plutonium within single cycle solvent extraction flowsheets for advanced fuel cycles. J. Nucl. Sci. Technol. 44 (3) 337-343. 

Coy, F.B. 2002. Developing computer models for the UREX solvent extraction process and performing a sensitivity analysis of variables used for optimizing flowsheets for actinide transmutation. Thesis. The University of Texas at Austin. 

Jenkins, J.A., Mills, A.L., Thompson, P.J., Jubin, R.T. 1993. Performance of centrifugal contactors on uranium and plutonium active PUREX flowsheets. In Solvent Extraction in the Process Industries ISEC 93, York, UK, September 16-21. Logsdail, D.H., Slater, M.J. Eds. Elsevier Applied Science, London and New York. 

Law, J.D., Herbst, R.S., Todd, T.A. et al. 2001. The universal solvent extraction (UNEX) process. II. Flowsheet development and demonstration of the UREX process for the separation of cesium, strontium, and actinides from actual acidic radioactive waste. Solvent Extr. IonExch. 19 (1) 23-36. 

A solvent-extraction flowsheet is broken down into sections such as extraction, scrub, and strip. For each section, one or more component in a process fluid must be moved from one phase to the other phase with a specified degree of completeness. The first design problem is to determine the number of stages for each section to accomplish the required component transfer. With the well-defined stages of the centrifugal contactor, the following extraction factor (E) can be used to estimate the number of stages required ... 

Law, J. D., R. S. Herbst, T. A. Todd, et al. 2001. Flowsheet Testing of the Universal Solvent Extraction Process for the Simultaneous Separation of Cesium, Strontium, and the Actinides from Dissolved INEEL Calcine. Proceedings of WM-01, February 25-March 1, 2001, Tucson, AZ. 

Leonard, R. A., S. B. Aase, H. A. Arafat, et al. 2002a. Simulant Flowsheet Test with Modified Solvent for Cesium Removal Using Caustic-side Solvent Extraction. Argonne National Laboratory Report ANL-02/22, Argonne, IL. 

Rivalier, P. and J-Y. Lanoe. 2000. Development of a New Miniature Short-residence-time Annular Centrifugal Solvent Extraction Contactor for Tests of Process Flowsheets in Hot Cells. ATALANTE 2000, October 24—26, Avignon, France. 

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