Chemical furnace

These bricks may therefore be called nlicecus oj etone bricks, and will no doubt prove admirably adapted for the construction of many kinds of chemical furnaces. A red fire-brick is likewise manufactured at Windsor, the analysis of the clay from which it is prepared being... 

The combustion of tantalum in nitrogen was studied in detail by Borovinskaya et al.10 Experimental measurements of the propagation characteristics were reported and the various nitrides of tantalum were synthesized under appropriate conditions. The study also showed the use of the chemical furnace technique for the preparation of high-temperature metastable phases. 

There are two minor papers that deal with the practice of chemistry at the University of Edinburgh in the latter half of the 18th century, one concerning the availability and manufacture of chemical glassware (an under-studied topic)21 and the second with the supply of heat sources in laboratories (also under-studied) and, in particular, with the new form of chemical furnace designed by Joseph Black (1728-1799).22 Though once very widely used, no original form of the furnace appears to have survived. This is a typical example of the poor survival rate, which may well be a factor in the paucity of papers on chemical apparatus. 

R. G. W. Anderson, Joseph Black and his chemical furnace , in Making Instruments Count Essays on Historical Scientific Instruments presented to Gerard L Estrange Turner, ed. R. G. W. Anderson, J. A. Bennett and W. F. Ryan, Variorum, Aldershot, 1993, pp. 118-126. 

DESCENDUM, or DESCENSORIUM — An Oven Or Chemical Furnace into which liquid goes down when separated from the gross matter. 

Fig. 6. Schemes for SHS densification. I-sample 2-press die 3-pressure-transmitting medium 4-pressing body 5-ignitor 6-metal container 7-massive piston 8-explosive 9-electric fuse 10-glass containers ll- chemical furnace mixture.

The values of Xf and C are determined from the energy equivalents of equipment and inputs into the plant. These components include capital equipment, electricity, chemicals, furnace, boiler and hydrogen plants, organic wastes and waste collection. 

Le Fevre describes and figures chemical furnaces and apparatus, including an air-thermometer with two bulbs and a water-index, for measuring temperatures and also shows a lamp furnace with an oil lamp (which could have one or more wicks of different sizes) adjustable by a screw. ... 

First of all, a technical clarification is necessary in the wider sense, motor fuels are chemical compounds, liquid or gas, which are burned in the presence of air to enable thermal engines to run gasoline, diesel fuel, jet fuels. The term heating fuel is reserved for the production of heat energy in boilers, furnaces, power plants, etc. 

It is used in certain nickel-based alloys, such as the "Hastelloys(R)" which are heat-resistant and corrosion-resistant to chemical solutions. Molybdenum oxidizes at elevated temperatures. The metal has found recent application as electrodes for electrically heated glass furnaces and foreheaths. The metal is also used in nuclear energy applications and for missile and aircraft parts. Molybdenum is valuable as a catalyst in the refining of petroleum. It has found applications as a filament material in electronic and electrical applications. Molybdenum is an... 

A technique is any chemical or physical principle that can be used to study an analyte. Many techniques have been used to determine lead levels. For example, in graphite furnace atomic absorption spectroscopy lead is atomized, and the ability of the free atoms to absorb light is measured thus, both a chemical principle (atomization) and a physical principle (absorption of light) are used in this technique. Chapters 8-13 of this text cover techniques commonly used to analyze samples. 

Since detailed chemical structure information is not usually required from isotope ratio measurements, it is possible to vaporize samples by simply pyrolyzing them. For this purpose, the sample can be placed on a tungsten, rhenium, or platinum wire and heated strongly in vacuum by passing an electric current through the wire. This is thermal or surface ionization (TI). Alternatively, a small electric furnace can be used when removal of solvent from a dilute solution is desirable before vaporization of residual solute. Again, a wide variety of mass analyzers can be used to measure m/z values of atomic ions and their relative abundances. 

A wide variety of special-purpose incinerators (qv) with accompanying gas scmbbers and soHd particle collectors have been developed and installed in various demilitarisation faciUties. These include flashing furnaces that remove all vestiges of explosive from metal parts to assure safety in handling deactivation furnaces, to render safe small arms and nonlethal chemical munitions fluidized-bed incinerators that bum slurries of ground up propellants or explosives in oil and rotary kilns to destroy explosive and contaminated waste and bulk explosive. 

In 1990, U.S. coke plants consumed 3.61 x 10 t of coal, or 4.4% of the total U.S. consumption of 8.12 x ICf t (6). Worldwide, roughly 400 coke oven batteries were in operation in 1988, consuming about 4.5 x 10 t of coal and producing 3.5 x 10 t metallurgical coke. Coke production is in a period of decline because of reduced demand for steel and increa sing use of technology for direct injection of coal into blast furnaces (7). The decline in coke production and trend away from recovery of coproducts is reflected in a 70—80% decline in volume of coal-tar chemicals since the 1970s. 

Formation of Airborne Emissions. Airborne emissions are formed from combustion of waste fuels as a function of certain physical and chemical reactions and mechanisms. In grate-fired systems, particulate emissions result from particles being swept through the furnace and boiler in the gaseous combustion products, and from incomplete oxidation of the soHd particles, with consequent char carryover. If pile burning is used, eg, the mass bum units employed for unprocessed MSW, typically only 20—25% of the unbumed soHds and inerts exit the combustion system as flyash. If spreader-stoker technologies are employed, between 75 and 90% of the unbumed soHds and inerts may exit the combustion system in the form of flyash. 

High process temperatures generally not achievable by other means are possible when induction heating of a graphite susceptor is combined with the use of low conductivity high temperature insulation such as flake carbon interposed between the coil and the susceptor. Temperatures of 3000°C are routine for both batch or continuous production. Processes include purification, graphitization, chemical vapor deposition, or carbon vapor deposition to produce components for the aircraft and defense industry. Figure 7 illustrates a furnace suitable for the production of aerospace brake components in a batch operation. 

Protective-Atmosphere Furnaces. These furnaces are used where the work caimot tolerate oxidation or where the atmosphere must provide a chemical or metallurgical reaction with the work. In some cases, mainly in high temperature appHcations, the atmosphere is required to protect the electric heating element from oxidation. 

The burning of the ligneous portion of the black Hquor produces sufficient heat in the furnace to sustain flash drying of residual moisture, salt-cake reduction, and chemical smelting. The heat in the gas passing through the furnace, boiler, and economi2er produces steam for power and process. 

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