Melt, procedure

Lead and its alloys are generally melted, handled, and refined in cast-iron, cast-steel, welded-steel, or spun-steel melting ketdes without fear of contamination by iron (qv). Normal melting procedures require no dux cover for lead. Special reactive metal alloys require special alloying elements, duxes, or covers to prevent dross formation and loss of the alloying elements. 

Compounds 5,6,7, and 8 are liquids at room temperature and a low temperature in situ crystallization was performed on the diffractometer using a miniature zone melting procedure with focused infrared light or C02 laser beam [/]. All bond lengths given are corrected for libration [54]. 

In some cases such as in the analysis of ZrC>2, use is made of ammonium salts. This has the advantage that the melting procedure can be performed in quartz crucibles limiting the risk of contamination, that the salts are relatively pure as they can be prepared from pure chemicals (NH3 gas and CIHSO3, e.g. see Ref. [312]), and that the excess can be volatilized at low temperatures which makes the risk of analyte losses through volatilization low. For example, with NH4HSO4, the melting procedure can be performed at 400 °C and the excess of flux volatilized at below 500 °C. 

The time-dependent formation of S7 from Sg in liquid sulfur at 120 °C was monitored using the two neighboring Raman lines of S7 (360 cm ) and Sg (196 cm ) in the spectra of the melt quenched at certain time intervals after the start of the melting procedure of pure Sg in the aluminum oven. The intensity ratio I(360)/I(196) continuously increased from zero to 0.28, the final value being reached after ca. 10 h. By independent experiments it had been shown before that this intensity ratio is proportional to the S7 concentration in liquid Sg. The temperature dependence of I(360)/l(196) was used to demonstrate that the S7 concentration in liquid sulfur increases from 115 to 159 °C approximately by a factor of 2 but absolute concentrations could not be determined in this way [80]. 

The total iron content may be determined directly in the soil by the X-ray fluorescence analysis or by a spectrographic method. In the case of classic methods, the soil sample should be first decomposed either by melting with Na2C03 or by the action of hydrofluoric acid. The melting procedure is more advantageous, since in this case further elements can also be determined simultaneously with iron. When it is only necessary to determine iron, it is advantageous to use the decomposition with hydrofluoric acid, which does not need the separation of silicic acid. In solution, iron is determined most frequently by the photometry, AAS or polarography. ... 

The Ru(ll) complex is stable in air in the solid state and is slowly oxidized in solution to the Ru(III) complex. The Ru(III) complex may be prepared by Ag oxidation or obtained directly from [(NH3)5Ru(0S02CF3)] in a pyrazine melt. Procedures similar to that described allow the syntheses of a great variety of pentaanunine complexes. 

Pure Li is prepared (via the method of Ruff and Johannsen) from LiBr which is melted in an electric arc in the presence of 10-15% LiCl (the LiBr is obtained from LigCOs by evaporating the latter from hydrobromic acid). Fig. 260 is a scale drawing (1 5) of the Muthmann electrolysis vessel used for the melting procedure. It is made of copper and its upper part is cooled with water. While... 

The melting range is dependent on the heating rate. Using the Class I melting procedure outlined in NF XIII, isocarboxazid melts between 105° and 108°C (6). 

Allowed melting procedures vacuum arc furnace or electroslag remelting. 

If one of the reaction components has a comparatively low boiling temperature, significant evaporation can occur during the are-melting procedures. This is especially the case for the rare earth metals samarium (boils at 2050 K), europium (1870 K), thulium (2000 K), and... 

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