Waste flowsheet

Figure 3 shows a flowsheet for plutonium processing at Rocky Flats. Impure plutonium metal is sent through a molten salt extraction (MSE) process to remove americium. The purified plutonium metal is sent to the foundry. Plutonium metal that does not meet foundry requirements is processed further, either through an aqueous or electrorefining process. The waste chloride salt from MSE is dissolved then the actinides are precipitated with carbonate and redissolved in 7f1 HN03 and finally, the plutonium is recovered by an anion exchange process. 

The above information was used to develop conceptual flowsheets for the extraction of all of the actinides (U, Np, Pu, Am, and Cm) from high-level liquid waste from PUREX processing using 0.4 M 0fuel using 0.8 M DHDECMP in DEB. In both flowsheets, no oxidation state of Pu is necessary since the III, IV, and VI state extract into the organic phase. 

Conceptual flowsheet for the extraction of actinides from high-level liquid waste using 0.4 M 0<)>D[IB]CMP0 in DEB. 

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

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. 

Figure 21 Composite flowsheet of waste treatment in soap and detergent industry (from Ref. 13).

Figure 2 depicts the process equipment and Figure 3 is a flowsheet for a 2700 tonnes of prepared waste per day processing plant (14). The prepared feed of 30% solids is slurried in water and recycle oil and fed to the reactor at 350 C and 2 x 10 kPa. 

The work on hi level waste solidification has led to applications of the same materials to other areas of waste management. These include decontamination of defense wastes currently in tank storage at Richland, WA, selective separation of Cs for beneficial uses, and development of a process flowsheet for conversion of Zircaloy fuel cladding hulls to sodium zirconate for use in waste stabilization. Each is briefly described below. 

The Zircaloy Conversion Process (24, 25, 26) is a concept whereby one waste stream, Zircaloy fuel hulls, can be utilized in the stabilization of a second waste stream. The process flowsheet which is conceptual in nature, details the steps required to convert the fuel hulls to sodium zirconate to be used in the solidification of liquid high level waste. 

Fig. 1. Schematic flowsheet of uranium processing (acid leach and ion exchange) operation. Numbers refer to the numbers that appear in the boxes on the flowsheet. Operations (3), (6), (9), and (11) may be done by thickening or filtration. Most often, thickeners are used, followed by filters. The pH of the leach slurry <4) is elevated to reduce its corrosive effect and to improve the ion-exchange operation on the uranium liquor subsequently separated, In tile ion exchange operation (7), resin contained in closed columns is alternately loaded with uranium and then eluted. The resin adsorbs the complex anions, such as UC fSO 4-. in which the uranium is present in the leach solution. Ammonium nitrate is nsed for elution, obtained by recycling the uranium filtrate liquor after pH adjustment. Iron adsoibed with the uranium is eluted with it. Iron separation operation (8) is needed inasmuch as the iron hydroxide slurry is heavily contaminated with calcium sulfate and coprecipitated uranium salts. Therefore, the slurry is recycled to the watering stage (3). Washed solids from 1,6). the waste barren liquor from (7), and the uranium filtrate from (11) are combined. The pH is elevated to 7.5 by adding lime slurry before the mixture is pumped to the tailings disposal area. (Rio Algom Mines Limited, Toronto)...

Fig. 1. Simplified flowsheet of incineration main in a hazardous waste treatment complex. (After Tillman)...

Law, J.D., Herbst, R.S., Todd, T.A. 2002. Integrated AMP-PAN, TRUEX, and SREX testing. II. Flowsheet testing for separation of radionuclides from actual acidic radioactive waste. Sep. Sci. Technol. 37 (6) 1353-1373. 

Herbst, R.S., Law, J.D., Todd, T.A. et al. 2002. Universal solvent extraction (UNEX) flowsheet testing for the removal of cesium, strontium, and actinides elements from radioactive, acidic dissolved waste. Solvent Extr. IonExch. 20 (4—5) 429 445. 

Under the 3rd EURATOM Framework Program on the management and disposal of radioactive wastes, Italian researchers of the National Commission for Research and Development of Nuclear and Alternative Energy Sources (ENEA) tested a TRUEX flowsheet, aiming at achieving an alpha decontamination factor (DF) greater... 

Two countercurrent tests were carried out with simulated waste at the INL (116, 117). The first flowsheet implemented (11 extraction stages,... 

A SETFICS countercurrent hot test was recently conducted with high loading of salt-free flowsheet (in order to reduce the solvent volume and the amount of waste stream by 50%) in the JAEA Chemical Process Facility (CPF) as part of the feasibility demonstration of the NEXT process. The solvent consisted of CMPO and TBP,... 

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