Quartz crucible

Calcium Oxide (lime, Quicklime, Burnt Lime, Calx, Unslaked Lime, Fluxing Lime). CaO, mw 56.08, white or greyish-white lumps or powd, mp 2580°, bp 2850°, d 3.25-3.40g/cc. SI sol in w with formation of calcium hydroxide and evolution of large amts of heat sol in acids, and insol in ethanol. Coml prepn consists of heating calcium carbonate in kilns at 1000—1100° until all of the C02 is driven off. Lab prepn is by burning calcium carbonate or calcium oxalate at about 800° using a quartz crucible in an electric furnace... 

Small solid seuaples can be analyzed directly by dynamic headspace sampling using a platinum coil and quartz crucible pyrolyzer and cold trap coupled to an open tubular column (341,369,379). This method has been used primarily for the analysis of mineral samples and of additives, catalysts and byproducts in finished polymers which yield unreliable results using conventional headspace techniques owing to the slow release of the volatiles to the headspace. At the higher temperatures (450-1000 C) available with the pyrolyzer the volatiles are more readily and completely removed from the sample providing for quantitative analysis. 

Seven ANL-PCS (Argonne National Laboratory - Premium Coal Sample) coals were analyzed by Py-FIMS in time resolved (TR) mode. Conventional characterization data on ANL-PCS coals have been described elsewhere (11). About 100 pg of -100 mesh coal were transferred into a quartz crucible and introduced into the high vacuum (10 Pa) of the ion source (200 C). The instrumental setup using a Finnigan... 

For the synthesis of phosphors, the sulfides are homogenized with readily decomposed compounds of the activators and coactivators in the presence of a flux and are fired in quartz crucibles at 800-1200 °C. 

About 1.0 g of the as-synthesized PMS was placed in a quartz crucible suspended in a furnace and heat treated at 523 to 723 K (heating rate 5 K/min, holding time 2 h). The argon flow rate was 1 L/min. All the volatile compounds that formed from the PMS during the heat treatment were flowed out under this condition. 

For example, the hot-zone of a Kayex CG6000 puller, as shown in Fig. 2.2a has the crystal diameter of 5.5in. and quartz crucible of 16in.. The hot-zone could be divided into six major components (1) radiation shield (or cone) (2) top side insulation (3) additional side insulation (4) bottom insulation (5) top-wall insulation and (6) argon venting. The default hot-zone from Kayex did not include the cone and the top-wall insulation. The room for the bottom and side-wall insulations was still large. The temperature distribution calculated by STHAMAS is also shown on the left hand side of Fig. 2.2a,... 

Another attempt to make feed rods for FZ crystal growth from cheap starting material is to melt solar (or lower) grade raw silicon in a quartz crucible and pull a rod of the desired diameter after the CZ method, not necessarily a single crystal. A lot of impurities can be removed by segregation and in the subsequent FZ step, almost all oxygen and most of the other impurities can be removed, too. However, the actual costs of such an approach must be carefully considered, but it is still an option to overcome the diameter limitations of the Siemens process. 

The behaviour of quartz crucibles and the interaction with liquid silicon was examined thoroughly to control the oxygen content in Cz wafers [42]. Important factors are the dissolution of quartz in liquid silicon and the evaporation of SiO from the melt. This results in a transport process of Si02 via the silicon melt into the gas phase and respectively to crucible dissolution and silicon melt contamination. 

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. 

In the block casting process, source silicon is melted in a first quartz crucible and poured into a second, nitride-coated crucible. Heaters are used to control cooling to produce columnar grains. Relative to Bridgeman, faster solidification is possible but at the expense of smaller grains. 

Catalyst preparation. The catalysts were prepared by heating and TiO (anatase) powders in a quartz crucible in a high temperature oven for 3 hrs at 1150-1250°C. The fused catalysts were divided into small particles, and the 0.71-1.41 mm fraction was used in the activity measurements. Activated catalysts were prepared b reduction of the precursors in 1 atm of hydrogen for 1 hr at 450 u. 

H 0lt/30%H202), rinsed several times with water and baked at 180°C. Three small sodium pellets (400 mg, Aldrich) are placed in a 1 cm x 1 cm quartz crucible situated in a triple-strand tungsten wire spiral basket (R. D. Mathis Co., Long Beach, Ca.). Provided the... 

A sample holder, to be used for ignition studies, was described by Charsley et al. (129). The sample and reference materials were placed in flat-bottomed quartz crucibles, 6 mm in diameter and 20 mm in length. The crucibles were supported by plate-type Chromel-Alumel thermocouples, fitted with locating pins and having 0.5-mm-diameter wire leads. 

Weigh the powdered sample of bone (0.5-2.0 g) in a quartz crucible and moisten with 6N nitric acid. Evaporate to dryness at a temperature of 90-105°C and transfer to a muffle furnace heated to 450°C. Ash for 6-8 h. Cool and treat the residue with a few drops of 6N nitric acid and 2ml hydrogen peroxide. Evaporate to dryness and ash at a temperature of... 

A quartz crucible 12 cm. long and 2 cm. in diameter (a pure quartz tube fused at one end) is filled with 20 to 30 g. of powdered Si. This crucible is inserted into another fused quartz tube, which is 60 cm. long and 3 cm. in diameter, and has a male groimd joint at the top (Fig. 219). The 5-mm. argon inlet tube is fused at the... 

The mixture is heated for 15 minutes at 800 °C in a covered quartz crucible. 

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