Flowsheets final

Clearly, the time chart shown in Fig. 4.14 indicates that individual items of equipment have a poor utilization i.e., they are in use for only a small fraction of the batch cycle time. To improve the equipment utilization, overlap batches as shown in the time-event chart in Fig. 4.15. Here, more than one batch, at difierent processing stages, resides in the process at any given time. Clearly, it is not possible to recycle directly from the separators to the reactor, since the reactor is fed at a time different from that at which the separation is carried out. A storage tank is needed to hold the recycle material. This material is then used to provide part of the feed for the next batch. The final flowsheet for batch operation is shown in Fig. 4.16. Equipment utilization might be improved further by various methods which are considered in Chap. 8 when economic tradeoffs are discussed. 

Figure 4.16 Final flowsheet for the production of butadiene sulfone in a batch process.

This contributes materially to the readability of the flowsheets. Each line on the flow sheet must represent an actual section or run of piping in the final plant and on the piping drawings. 

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 flowsheet shown in the introduction and that used in connection with a simulation (Section 1.4) provide insights into the pervasiveness of errors at the source, random errors are experienced as an inherent feature of every measurement process. The standard deviation is commonly substituted for a more detailed description of the error distribution (see also Section 1.2), as this suffices in most cases. Systematic errors due to interference or faulty interpretation cannot be detected by statistical methods alone control experiments are necessary. One or more such primary results must usually be inserted into a more or less complex system of equations to obtain the final result (for examples, see Refs. 23, 91-94, 104, 105, 142. The question that imposes itself at this point is how reliable is the final result Two different mechanisms of action must be discussed ... 

Input Plant flowsheet in final state, F constraint being clobbered, q. Output White Knight, W for the constraint q. begin for q do begin... 

A schematic flowsheet for molybdenum recovery from porphyry coppers is shown in Figure 2.34. Here the important role is played by flotation. The first stage involves collective flotation of copper and molybdenum. The floated product is upgraded through two or three cleaning flotations. Finally, molybdenum is recovered by depressing copper values. In order to depress a mineral, some kind of oxidation should be implied on its surface, or re-... 

Another, more modern, route of processing the yellow cake is shown in Figure 5.38, accomplishes the production of enriched uranium oxide entirely by pyroprocessing. Thus, uranium is finally obtained in three forms metallic uranium, enriched uranium dioxide, and natural uranium dioxide. As the flowsheet shows, and as briefly described herein, these are essentially the products of hydro and pyro-based processing schemes. 

Clearly, it is not possible to recycle directly from the separators to the reactor since the reactor is fed at a time different from that at which the separation is carried out. A storage tank is needed to hold the recycle material. This material is then used to provide part of the feed for the next batch. The final flowsheet for batch operation is shown in Figure 14.25. 

Development work was carried out with different collectors. At the end, N-( 1,2 dicar-boxy ethyl)-/ octadecil sulphosuccinamate emulsified with fuel oil in a ratio of 8 1 was the final collector. The flotation flowsheet is shown in Figure 21.2. The final tin flotation reagent scheme included collector R845 (Cytec) emulsified with fuel oil as a tin collector (890 g/t) H2S04 for pH control citric acid (200 g/t) andNa2SiF6 (450 g/t). 

Collector PL520 was selected as the final collector due to its low-frothing properties. After selection of the collector, a series of final locked cycle tests were conducted using the flowsheet shown in Figure 21.10. The final reagent scheme is shown in Table 21.13. 

Figure 21.10 Final flowsheet for tin recovery from fines at the Huanuni Concentrator.

Extensive laboratory testing was performed on the Greenbushes gravity tailing, followed by pilot plant testing at the mine site. The generalized final flowsheet, evaluated in the pilot plant tests, is shown in Figure 23.5. 

Figure 23.5 Final flotation flowsheet for Ta/Nb flotation from gravity tailings.

A depressant system developed for beneficiation of Ta/Nb-Zr ores involves oxalic acid-hydro fluoro silicic acid and depressant SHQ. SHQ is a mixture of a low-molecular-weight acrylic acid and condensation product of disulphonic acid (Suspendol PKK, manufactured by Cognis, Germany). After the development of the final reagent scheme, a series of locked-cycle tests were performed using the flowsheet shown in Figure 23.7. 

Figure 23.7 Final flotation flowsheet used in the continuous locked-cycle tests.

Figure 23.12 Final treatment flowsheet and reagent scheme for beneficiation of Ta/Nb-Zr ores.

Good separation efficiency was achieved after >80% of the Fe-hydroxide was removed. Good Fe-hydroxide removal was achieved with the use of alkaline acid scmbbing and desliming. The final decoating flowsheet is shown in Figure 23.16. 

Figure 24.13 Final flotation flowsheet with points and levels of reagent additions.

The final flowsheet that was developed for chromium removal is shown in Figure 25.13. The concentrate was scrubbed with alkaline followed by desliming. The deslimed concentrate was subjected to chromium flotation followed by a single cleaning stage. 

The flowsheet (Figure 25.18) shows the final flowsheet developed for the beneficiation of the Guadalajara ore. This flowsheet consists of two flotation circuits (a) gangue prefloat circuit, where the apatite and calcite are recovered, and (b) titanium flotation circuit, where... 

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