Fusion mixtures

Guanine [7340-5], an organic dye, is also known as Cl 75170 [7340-5], Materials are fusion mixtures. 

Our researches of a method fire assay (FA) of ores have shown that the losses of noble metals (NM) in scoria s FA hardly depend on composition of used fusion mixture. Usage of ultrasonic (US) oscillations of low frequency allows lowering on 50-100° temperature FA, to reduce time in 3-4 times. Even under unfavorable conditions thus the extent of extraction NM is conserved at FA on NiS (Ni S ) or Sn and is augmented at usage as a collector Pb or Cu. 

The thin film of oxide which remains in the casserole is dissolved by treating with a little constant-boiling hydrobromic acid (Note 7) the solution obtained may then be evaporated and the residue added to the next fusion mixture. 

Fusions with (a) sodium carbonate or fusion mixture, (b) borax and lithium metaborate, (c) alkali bifluorides, and (d) alkali hydrogensulphates (slight attack in the last case above 700 °C, which is diminished by the addition of ammonium sulphate). 

Insoluble fluorosilicates are brought into solution by fusion with four times the bulk of fusion mixture, and extracting the melt with water. In either case, the solution is treated with a considerable excess of ammonium carbonate, warmed to 40 °C, and, after standing for 12 hours, the precipitated silicic acid is filtered off, and washed with 2 per cent ammonium carbonate solution. The filtrate contains a little silicic acid, which may be removed by shaking with a little freshly precipitated cadmium oxide. The fluoride in the filtrate is determined as described in Section 11.59. 

The cell fusion mixture is transferred to a culture medium containing hypoxanthine, aminopterin and thymidine (HAT medium). Unflised myeloma cells are unable to grow as they lack HGPRT. Unflised normal spleen cells can grow but their proliferahon is limited and they eventually die out. The hybridoma cell can proliferate in the HAT medium as the normal spleen cell supplies the enzyme which enables the hybridoma to utilize extracellular hypoxanthine. 

Oxide glasses have been reported by Crisp Wilson (1978a,b, 1979), Wilson et al. (1980), and Hill Wilson (1988a). The fusion mixtures contain silica, alumina and calcium carbonate to which sodium carbonate or calcium orthophosphate may be added. They may be represented thus, with fusion temperature given in parentheses ... 

In fluoride glasses, calcium fluoride is an essential constituent, but generally cryolite, NajAlFg, is also added as a flux to lower the temperature of fusion. Aluminium orthophosphate is also generally added to the fusion mixture for various reasons. Of course, the various elements may be added in different ways. Thus, calcium orthophosphate, aluminium fluoride and sodium carbonate are often used in the preparation of fluoride glasses. 

Fluoride glasses are difficult to classify because the various constituents can be added to the fusion mixture in several ways. However, glasses of the Laboratory of the Government Chemist (Wilson Kent, 1973 Kent, Lewis Wilson, 1979 Wilson et al., 1980 Hill Wilson, 1988a), which form the basis of many commercial cements, can be represented as... 

K-2 Explosive (Russ K-2 Splav, K-2 Fusion, Mixture K-2). Mixture containing TNT 80 and DNN 20%, used for loading 82mm Land Mines made from cast iron. It was less toxic than K-l, described above Refs 1) Shilling (1946), 240-41 2) PATR... 

Fusion Mixture. A mixt of Na and K carbonates used to fuse in sol substances of high mp s (such as ores) in order to render them soluble in die form of double carbonates. Fusion can also be achieved by heating insol... 

An Intimate mixture of 25g stibnite, llg iron powder or filings, 2.5g anhydrous sodium sulfate, and 0.6g charcoal is placed in a covered crucible and heated about 20 minutes with a Meker burner so that the fusion mixture softens but does not quite melt This is determined by momentarily stirring with an iron rod. The melt is allowed to cool and the crucible is broken. A mass of crude fused antimony weighing about 15g is found at the bottom this is mechanically cleaned and then washed with hot water. 

The beaker ia immediately immersed in an oil bath preheated to 100°C. When the fusion mixture begins to melt and effervesce with evolution of hydrogen chloride heating ia temporarily interrupted. The reaction heats up to 140-150°C. After ten minutes the fusion is stirred thoroughly with a thermometer the temperature should not rise above 160°C. The bath is now maintained at 120° for one-half hour to complete the. reaction. It should be noted that a properly conducted fusion is the yield determining factor in this and the succeeding preparation. 

The fusion mixture outlined in 155 b is treated with cold methanol and aqueous sodium chloride as described. The first methanol-water filtrate is reacted separately with 3g of solid potassium iodide to precipitate a small additional amount of product The successive teachings with water are carried out as in the previous procedure. To these combined extracts lOg of potassium iodide are added with stirring. 

Feeder cells for fusion cultures (see Note 6) essential for fusions employing rat myelomas. Quickly thaw irradiated rat fibroblasts, prepared as described in Note 6, just before commencing the cell fusion. Add the cells to 10 mL of serum-free DMEM, centrifuge, and wash once in serum-free DMEM Resuspend feeders in HAT medium just before addition of the fusion mixture. Alternatively, use thymocytes from spleen donors (mouse). 

Dilute the fusion mixture with DMEM (2 mL over a period of 2 min, and then 5 mL over 1 min). 

Fusion with Alkali and Other Agents. Calcium peroxide was added portionwise to the fusion mixture at 180°C. but did not change materially the nature of the yields or reaction products. It should be noted that, in these fusions, total recovery of solids was quite low owing to large conversion of organic matter to carbon dioxide. 

Residual HF mixtures of mineral acids, concentrated hot, namely HNQ3 + HC104 HN03 HN03 + HC1 also fusion mixtures... 

Carefully handle very hot containers, fusion mixtures and samples from muffle furnaces. 

Solid samples may frequently require fusions. Examples of such procedures in the literature are (a) the determination of aluminium, silicon and sodium in molecular sieves using a nitrous oxide/acetylene flame following fusion (1 part to 10 of fusion mixture) with sodium carbonate, sodium... 

The tests are carried out upon a clean charcoal block in which a small cavity has been made with a penknife or with a small coin. A little of the substance is placed in the cavity and heated in the oxidizing flame. Crystalline salts break into smaller pieces burning indicates the presence of an oxidizing agent (nitrate, nitrite, chlorate, etc.). More frequently the powdered substance is mixed with twice its bulk of anhydrous sodium carbonate or, preferably, with fusion mixture (an equimolecular mixture of sodium and potassium carbon-... 

Table V.ll Sodium carbonate fusion The residue, R, free from lead and silver salts, or the original substance, if lead and silver salts are absent, is mixed with 5-6 times its weight of pure, sulphate-free, anhydrous Na2C03 or with a mixture of equal parts of Na2C03 and K2C03 (fusion mixture). The mixture is heated upon Pt foil or in a Pt crucible until a tranquil melt is obtained. (It may be necessary to heat over the blowpipe flame.) Allow to cool, extract the melt thoroughly by boiling it with water. Filter.

The autoclave is then cooled and any excess pressure is released through the valve before loosening the top. If the fusion has been carried out properly, the fusion mixture is a dull, dirty yellow in color. If the color is too light, the fusion was not continued long enough. Too long a fusion, on the other hand, produces a mixture which is brown in color and which smells strongly of ammonia. Some ammonia is always formed, however, even under the correct conditions. 

The fusion mixture from (b) is dissolved in 2 liters water at 80°C., and a vigorous stream of air is passed through the solution until no more indigo is formed in a filtered test sample when shaken with air. The precipitated dye is filtered off, washed with water, boiled with dilute hydrochloric acid to remove all of the lime, filtered again, washed thoroughly with water, and finally dried in a steam heated oven. The yield is 12 to 12.5 grams, or 80 to 82 per cent of the theoretical amount based on the phenylglycine-o-carboxylic acid. 

In recent years, a number of especially resistant iron alloys have appeared on the market and have been rapidly adopted. They are, essentially, nickel-chrome-iron alloys, usually containing very little carbon. These alloys are very resistant to acids and alkalis and are used chiefly where high resistance to chemicals is the deciding factor. The different VA-steels, and the English S-80, are examples of these alloys which vary in composition depending on the particular application. These alloys withstand concentrated nitric acid, and other acids, except hydrochloric, scarcely attack them at all. They are especially important in modem high pressure syntheses. Potassium hydroxide scarcely attacks these alloys even in fusion mixtures, and they are quite satisfactory, therefore, for indanthrene fusions. (Nickel is also suitable in this particular case.)... 

The procedure is quite similar to that given above for y acid except that it is desirable to use somewhat more water in the fusion mixture — 160 grams instead of 120 grams. The fusion is carried out at a slightly lower temperature, 200-205°C., for 7 hours. The yield of J acid is about equal to that of y acid, i.e., the equivalent of 95 grams of pure material... 

This process involves the same reactions used in the process above, but in reverse sequence alkali fusion first, followed by the Bucheref reaction. In this case, aqueous ammonia is not used, but instead the inexpensive ammonium sulfate which is decomposed by the alkali in the fusion mixture to generate ammonia. Furthermore, the sulfite formed in the fusion reaction is enough to effect the Bucherer reaction. 

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