Extraction section

Anthony G. Fonseca, Ph.D., Director, Coal Utilization, CONSOL, Inc. Member, American Chemical Society, Society for Mining, Metallurgy, and Extraction (Section 27, Energy Resources, Conversion, and Utilization)... 

The extractive column must be a double-feed column, with the solvent feed above the primary feed the column must have an extractive section. 

Polymerization to Cg and CJj olefins is the chief side reaction. Polymerization increases with extraction temperature and with the hold-up time in the extraction section. It limits the temperature used to obtain high extraction rates. 

For soil samples, sufficient sample cleanup could be conducted even if the alumina column was changed to a Sep-Pak Alumina N cartridge (Waters) by the following process. The entire sample of the dried n-hexane extract (Section 6.2) is introduced into a Sep-Pak Alumina N cartridge, and the column is washed with 50 mL of n-hexane. Subsequently, pyriminobac-methyl is eluted with 3 mL of ethyl acetate, the solvent is evaporate to dryness under reduced pressure and the residue is dissolved in an appropriate volume of acetone for GC analysis. 

Total volume of liquid in extraction section Width of channel perpendicular to screw flights in screw extruder... 

Weight fraction of volatile component at interface Equilibrium weight fraction of volatile component Weight fraction of volatile component at inlet to extraction section Weight fraction of volatile component at exit of extractor... 

Befow ICP-MS determination Umit. Accumulation in the back extraction section. 

Six filters for each level of concentration were spiked using variable volume pipettes. The following volumes 13, 25, 50, 100, and 200 yL of the 10 mg/mL solution yielded 0.13, 0.25, 0.50, 1.00 and 2.00 mg of sodium dichloroisocyanurate dihydrate on a filter, respectively. When the filter was dry, the "filter extraction" section was followed. The end-point volumes were converted to milligrams from the calibration curve and the percent recoveries were calculated. 

Heap (dump) acid leaching of copper sulfide ores is possible with the aid of microbial oxidation. Not all copper minerals are sulfidic, however— malachite, azurite, and chrysocolla are basic copper carbonates—and sulfuric acid heap leaching of low-grade copper carbonate ores can give solutions from which the Cu2+ ion can be separated by solvent extraction (Section 17.3) and copper metal obtained by electrowinning. 

If necessary, select a sample cleanup method. Cleanup could be required if resolution is poor, if the salt content is high, or if the capillary fouls. Cleanup might involve solid-phase extraction (Section 28-3), protein precipitation, or dialysis (Demonstration 27-1). 

Mist extraction section for removing a maximum of the tiny liquid droplets remaining in the gas stream after passing through the primary and secondary separation sections. The usual oilfield separator employs either the impingement principle or the centrifugal force principle as the primary mechanism of mist extraction. 

Within pressure plants, especially high-pressure extraction plants, different pressure levels are always given. The highest pressure in SFE plants is within the extraction section, followed by the separation step, and the CO2 storage. 

While the CO2 make-up system and the CO2 working-vessel are connected, in most cases, by a single piping line, and therefore simple protection is adequate, the numerous connection lines between the extraction section and the peripheral equipment have to undergo an accurate safety evaluation. 

The precipitation (Section 10.2) and extraction (Section 10.4) of coordination compounds under controlled conditions and their optical characteristics (Section 10.5) have been exploited, together with a miscellany of other procedures, for detecting selectively small traces of elements in very small volumes of a test sample. Such spot reactions have been painstakingly collected, refined and recorded by Fritz Feigl.83... 

The reaction conditions ensure that all cobalt catalyst remains in the aqueous phase and that only Co2+-compounds that are soluble in water are formed. The aqueous phase, after dilution with the water from the extraction section (Figure 1), is recycled partially to the decobaiting tube and partially to the catalyst formation section where the active catalyst is regenerated. 

In the acid deficient flowsheet the acid released from A1(N03)3 hydrolysis was neutralized to give an organic product containing 0.5 M U02(N03)2 but only 0.05 M HN03. The A1(N03)3, Na2Cr207 and FPs were retained in the aqueous raffinate from the extraction section, while the organic product was passed to the U/Pu partition contacter. 

Cognate preparation. 3-Aminopyridine. Prepare a cold sodium hypobromite solution from 32 g (10 ml, 0.2 mol) of bromine and 25 g (0.62 mol) of sodium hydroxide in 250 ml of water. Add in one portion 20 g (0.163 mol) of finely powdered nicotinamide (Expt 6.169) and stir vigorously for 15 minutes. Warm the solution in a water bath at 75 °C for 45 minutes. Isolate the crude product by continuous ether extraction (Section 2.22) of the cooled reaction mixture after saturation with sodium chloride. Dry the extract over potassium hydroxide pellets and remove the ether. Crystallise the dark residue from a 4 1 mixture of benzene-light petroleum (b.p. 60-80 °C) with the aid of decolourising charcoal. The yield of almost colourless product, m.p. 63 °C, is 9.3 g (61%). 

Once the actual extraction-section aqueous feed is started, the process should be close to steady state after three residence times of the fluid have passed through the contactor stages. This action will typically take 15 to 30 min. If the above startup procedure is used, the decontamination factor for the extraction section will always be greater than the desired value, even during startup. Once steady-state operation is reached, the process is easy to control. The operator needs to check that the required feed flow rates are maintained, that the feed in each feed tank is appropriate, and that the rotors are spinning at the proper speed. Also, the feed tanks need to be monitored to avoid them running dry, and the effluent tanks need to be monitored for overflow. In plant operation, these tasks are usually automated. 

The scrub solution joins the aqueous waste feed stream to constitute the aqueous phase in the extraction section of the contactor cascade its low flow rate and low electrolyte concentration have little effect on the extraction section. The scrubbed solvent passes to the strip section of the cascade, where it is contacted with 1 mM nitric acid to transfer the cesium to the aqueous phase. This concentration of nitric acid was chosen to minimize the DCs for best stripping efficiency, while maintaining sufficient acidity to keep the amine protonated and sufficient ionic strength for adequate coalescence. 

A two-step destraction procedure was developed to maximize the amount o T102 residuum brought overhead. In the first step, toluene is used in a manner similar to conventional supercritical extraction to produce a nearly ash-free material for subsequent fractionation. This first step is called the non-reflux mode because the column of the FDV is maintained at the same temperature as the extraction section. In the second step, called the reflux mode, the column and finger are heated to a higher temperature than the extraction section, which causes the density of the fluid to decrease as it travels up the column and thus promotes reflux of the less-soluble components. These two steps are described below. 

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