Methods of extraction

Reduction by aluminium has been used to produce molten iron in situ for welding steel and as a method of extracting metals. 

The method of extraction is similar for each element involving first the roasting of the sulphide ore when the oxide is produced, for example... 

However, such mixer—settler methods are continuous only by virtue of repeating a sequence of similar stages to achieve a given degree of extraction. More fully continuous methods of extraction were designed as tower systems and later as screw conveyor systems as effective methods of soHds transport became reHable. 

Recovery from Ores and Clays. The preferred method of extraction of lithium from spodumene ore is the sulfuric acid process (18), used on ore concentrates of 5—6% Li O, representing 62—74% pure spodumene. Methods suitable for extraction from spodumene also can be used for petaUte, because the latter mineral converts to P-spodumene—Si02 soHd solution on heating to a high temperature. 

The method of extraction of Ru(III) from thiocyanate solutions by water soluble extractants in the presence of ammonium sulfate as salting out agent followed by photometric determination of it in extract has been elaborated. 

Determination of Na " and Na" ions in raw cosmetic materials was conducted with the developed method of flame photometry. A necessity of development of method of samples preparation arose up in the work process, as this spicily-aromatic raw material contained pectin in amount 0.1-0.5% and that prevented preparation of samples by standard method of extracts dilution and required incineration of analyzed sample, time of analysis was increased in 60 times. It was established that CaCl, solution with the concentration 0,4 % caused destmctions of the carbopol gel. It was established that the addition of 0,1% CaCl, and 0,1% NaCl salts solutions into the system intensified the effect of negative action of these salts onto the gel stmcture and the gel destmcted completely. 

Extent of comminution of the drug Method of extraction (temperature, length of time)... 

The result of taking into account the three factors mentioned - dose - degree of comminution - method of extraction - should be a tea that has an optimal amount of active constituents. But, at present ihere are very few studies which answer the often posed question What proportion of the active principles in the drug pass over into the tea With a hot-watcr infusion of chopped senna... 

Yttrium and lanthanum are both obtained from lanthanide minerals and the method of extraction depends on the particular mineral involved. Digestions with hydrochloric acid, sulfuric acid, or caustic soda are all used to extract the mixture of metal salts. Prior to the Second World War the separation of these mixtures was effected by fractional crystallizations, sometimes numbered in their thousands. However, during the period 1940-45 the main interest in separating these elements was in order to purify and characterize them more fully. The realization that they are also major constituents of the products of nuclear fission effected a dramatic sharpening of interest in the USA. As a result, ion-exchange techniques were developed and, together with selective complexation and solvent extraction, these have now completely supplanted the older methods of separation (p. 1228). In cases where the free metals are required, reduction of the trifluorides with metallic calcium can be used. 

When the distribution ratio is low, continuous methods of extraction are used. This procedure makes use of a continuous flow of immiscible solvent through the solution if the solvent is volatile, it is recycled by distillation and condensation and is dispersed in the aqueous phase by means of a sintered glass disc or equivalent device. Apparatus is available for effecting such continuous extractions with automatic return of the volatilised solvent (see the Bibliography, Section 9.10). 

This estimate can be improved for the forward difference scheme with (7 = 1 by means of the maximum principle and the method of extraction of stationary nonhomogeneities , what amounts to setting... 

Having no opportunity to touch upon this topic, we refer the readers to the aforementioned chapters of the manograph The Theory oof Difference Schemes , in which the method of extraction of stationary nonhomogeneities was employed with further reference to a priori estimates of z. The forward difference scheme with cr = 1 converges uniformly with the rate 0 h + r) due to the maximum principle. 

As more and more waste products are re-cycled, methods of extracting contaminants from them are needed. Reagent (6) is used to remove boron compounds from alkaline brine wastes. ... 

The wide distribution of chlorophylls throughout the plant kingdom facilitates the scrutiny of chlorophyll-rich vegetables for human nutrition with a view to their direct consumption. However, until now, little standardized information was available in the literature regarding the absolute total chlorophyll contents and the ratios of chlorophylls a and b in raw materials. The different analytical methods of extraction and quantification and the lack of data about moisture contents (that may vary considerably among varieties and preparations) can also influence the final contents of pigments. These factors have largely contributed to the discrepancies found in similar food samples. 

Timberlake and Bridle (1971) and later Wrolstad and Durst (1998) compared the acetone-chloroform method of extraction to acidified methanol and, depending on the material used, the anthocyanin recoveries were comparable or up to 30% higher with the use of acetone. This procedure proved efficient for a wide range of anthocyanin-rich plants to achieve high recoveries with minimal degradation. - ... 

A sequential analysis protocol includes three steps (1) extraction in water or other appropriate solvent for the colorant, (2) purification or concentration of the colorant, and (3) separation coupled with detection of the target molecule. Different methods of extracting synthetic colorants from foods have been developed using organic solvents followed by SPE protocols using as adsorption support RP-C18, amino materials, or Amberlite XAD-2. Eor qualitative evaluations, the easiest option for separating colorant molecules from unwanted ingredients found in an extract is SPE on polyamide or wool. 

Carmen Socaciu was bom in Cluj-Napoca, Romania and earned a BSc in chemistry in 1976, an MSc in 1977, and a PhD in 1986 from the University Babes-Bolyai in Cluj-Napoca, an important academic centre located in the Transylvania region. Dr. Socaciu worked as a researcher in medical and cellular biochemistry for more than 10 years, and became a lecturer in 1990 and full professor in 1998 in the Department of Chemistry and Biochemistry of the University of Agricultural Sciences and Veterinary Medicine (USAMV) in Cluj-Napoca. She extended her academic background in pure chemistry (synthesis and instrumental analysis) to the life sciences (agrifood chemistry and cellular biochemistry). Her fields of competence are directed especially toward natural bioactive phytochemicals (carotenoids, phenolics, flavonoids), looking to advanced methods of extraction and analysis and to their in vitro actions on cellular metabolism, their effects as functional food ingredients, and their impacts on health. 

Cane sugar is processed using one of two methods of extraction. One method uses diffusion and the other uses roller press extraction. Both methods may be used to make sugar and molasses fractions from sugarcane. However, roller press extraction is used by a greater percentage of the industry and, therefore, is the better method for a small-scale study. 

Mixing, wrist shaking, or tumbling combinations offer a simple, effective, but time-consuming and not highly reproducible method of extraction. Sample-to-solvent ratios are similar to Soxhlet ratios. Although sample manipulation is reduced, this technique requires nearly as much time as the Soxhlet method. Shake-flask extraction is low cost. 

Sonication of polychlorinated biphenyls (PCBs) from soils has been the subject of an interlaboratory study [196] with 129 participants. Two standard methods of extraction were evaluated EPA method 3540 for Soxhlet extraction and EPA method 3550 for sonication... 

The heat-induced retrieval protocol for extraction of formaldehyde-modified DNA from FFPE tissue sections provides a simple and effective method of DNA extraction from archival tissue samples.25,45 Based on PCR using three primer pairs ranging from 152-541 bp and a real time KTC-PCR analysis, the heat-induced retrieval protocol yields a better quality and quantity of DNA samples extracted from FFPE tissue sections than conventional methods of extraction.24 In addition, this heating protocol may provide an alternative approach for DNA extraction in some cases such as a recent publication by Ferrari et al. mentioned above.34... 

An anionic rhodium iodide carbonyl complex was supported on polyvinylpyrrolidone for the carbonylation of methanol in the presence of scC02 [98], Depending on the reaction conditions and method of extraction, less than 0.08% rhodium leaching was observed. Saturation of the support with methyl iodide was found to be vital to enhance the longevity and recyclability of the catalyst. 

Pulsed electric field is another alternative to conventional methods of extraction. PEF enhances mass transfer rates using an external electrical field, which results in an electric potential across the membranes of matrix cells that minimizes thermal degradation and changes textural properties. PEF has been considered as a nonthermal pretreatment stage used to increase the extraction efficiency, increasing also permeability throughout the cell membranes. 

Pierce RH Jr, Felbeck GT Jr (1972) A comparison of three methods of extracting organic matter from soils and marine sediments. In Povoledo D, Golterman HL (eds) Humic Substances. Center for Agriculture Publication and Documentation, Wageningen, Netherlands, pp 217-232... 

Proteins have been studied for a long time. Beccari published an account of his experiments to isolate gluten in 1747 In 1805 Einhof discovered that a fraction of wheat gluten was soluble, while in 1858 Denis showed that many proteins of both plant and animal origin were soluble in saline solutions. In 1859 Ritthausen started to prepare highly purified proteins, only to be criticised by Weyl for using alkali to extract the proteins. Weyl in his work used the Denis method of extraction with neutral salts. 

Efficiency of Extraction. Selectivity of Extraction. Extraction Systems. Extraction of Uncharged Metal Chelates. Methods of Extraction. Applications of Solvent Extraction. 

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