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Chromium emission

EPA, 1993. U.S. EPA, Office of Air Quality Planning and Standards, "Chromium Emissions from Chromium Electroplating and Chromic Acid Anodizing Operations Background Information for Proposed Standards," EPA-453[R-93-030a, Research Triangle Park, NC, July 1993. [Pg.494]

The decomposition of Cr(CO)6 has also been studied using a shock tube14. The maximum in the chromium emission spectra occurred at 1000 psec at 1000 °C and at 150 /isec at 1950 °C. The time required for cascade dissociation to Cr+6 CO is approximately 1 nsec. The delay in the emission spectra was attributed to excitation of the chromium by vibrationally excited CO. [Pg.199]

Estimates of U.S. Atomospheric Chromium Emissions from Anthropogenic Sources... [Pg.20]

Continental dust flux is the main natural source of chromium in the atmosphere volcanic dust and gas flux are minor natural sources of chromium in the atmosphere (Fishbein 1981). Chromium is released into the atmosphere mainly by anthropogenic stationary point sources, including industrial, commercial, and residential fuel combustion, via the combustion of natural gas, oil, and coal. Other important anthropogenic stationary point sources of chromium emission to the atmosphere are metal industries. It... [Pg.334]

Table 5-1. Estimates of U.S. Atmospheric Chromium Emissions from... Table 5-1. Estimates of U.S. Atmospheric Chromium Emissions from...
Source category Estimated number of sources Chromium emissions (metric tons/year) Estimated hexavalent chromium (%)... [Pg.336]

National Emission Standards for Coke Oven Batteries National Perchloroethylene Air Emission Standards for Dry Cleaning Facilities National Emission Standards for Chromium Emissions from Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks Ethylene Oxide Emissions Standards for Sterilization Facilities... [Pg.13]

Laboratory and Field Evaluations of a Methodology for Determining Hexavalent Chromium Emissions from Stationary Sources... [Pg.91]

Even after decades, the chromium emissions of a former cement plant induced a significant increase in the Cr content of wild and cultivated plants, without triggering phytotoxic nutritional damage in the flora, fauna and humans (Table 8.16). [Pg.117]

EPA Federal Register (1995) National Emission Standards for Chromium emissions from hard and decorative chromium electroplating and chromium anodizing tanks, vol 60. Research Triangle Park, pp 4547 993... [Pg.871]

Analysis of Trace or Minor Components. Minor or trace components may have a significant impact on quaHty of fats and oils (94). Metals, for example, can cataly2e the oxidative degradation of unsaturated oils which results in off-flavors, odors, and polymeri2ation. A large number of techniques such as wet chemical analysis, atomic absorption, atomic emission, and polarography are available for analysis of metals. Heavy metals, iron, copper, nickel, and chromium are elements that have received the most attention. Phosphoms may also be detectable and is a measure of phosphoHpids and phosphoms-containing acids or salts. [Pg.134]

The term laser is an acronym constmcted from light amplification by stimulated emission of radiation. The first operating laser was produced in 1960 (1). This laser, which used a crystal of mby [12174A9-17, chromium-doped alumina, Al202 Cr, and emitted a pulsed beam of collimated red light, immediately aroused scientific interest. [Pg.1]

The classical wet-chemical quaUtative identification of chromium is accompHshed by the intense red-violet color that develops when aqueous Cr(VI) reacts with (5)-diphenylcarba2ide under acidic conditions (95). This test is sensitive to 0.003 ppm Cr, and the reagent is also useful for quantitative analysis of trace quantities of Cr (96). Instmmental quaUtative identification is possible using inductively coupled argon plasma—atomic emission spectroscopy... [Pg.140]

Instrumental Quantitative Analysis. Methods such as x-ray spectroscopy, oaes, and naa do not necessarily require pretreatment of samples to soluble forms. Only reUable and verified standards are needed. Other instmmental methods that can be used to determine a wide range of chromium concentrations are atomic absorption spectroscopy (aas), flame photometry, icap-aes, and direct current plasma—atomic emission spectroscopy (dcp-aes). These methods caimot distinguish the oxidation states of chromium, and speciation at trace levels usually requires a previous wet-chemical separation. However, the instmmental methods are preferred over (3)-diphenylcarbazide for trace chromium concentrations, because of the difficulty of oxidizing very small quantities of Cr(III). [Pg.141]

Chromium Exposure Levels and U.S. Government Regulations. The level of exposure to chromium compounds for employees in industry and for the general population via waste disposal and industrial emissions is the subject of much regulation, research, and controversy. Some U.S. Government regulations, such as the Comprehensive Environmental Response, Compensation, and LiabiUty Act (CERCLA), also known as the Superfund Act, make no distinction as to the oxidation state of chromium (144). However, there is valence distinction in other regulations. [Pg.142]

Black and colored plates can also be obtained from chromic acid baths. The plates are mostly oxides (177). Black chromium plating bath compositions are proprietary, but most do not contain sulfate. The deposit has been considered for use in solar panels because of its high absorptivity and low emissivity (175). [Pg.143]

This method is used for the determination of total chromium (Cr), cadmium (Cd), arsenic (As), nickel (Ni), manganese (Mn), beiylhum (Be), copper (Cu), zinc (Zn), lead (Pb), selenium (Se), phosphorus (P), thalhum (Tl), silver (Ag), antimony (Sb), barium (Ba), and mer-cuiy (Hg) stack emissions from stationaiy sources. This method may also be used for the determination of particulate emissions fohowing the procedures and precautions described. However, modifications to the sample recoveiy and analysis procedures described in the method for the purpose of determining particulate emissions may potentially impacl the front-half mercury determination. [Pg.2206]


See other pages where Chromium emission is mentioned: [Pg.139]    [Pg.80]    [Pg.80]    [Pg.210]    [Pg.335]    [Pg.340]    [Pg.190]    [Pg.230]    [Pg.138]    [Pg.139]    [Pg.80]    [Pg.80]    [Pg.210]    [Pg.335]    [Pg.340]    [Pg.190]    [Pg.230]    [Pg.138]    [Pg.134]    [Pg.55]    [Pg.105]    [Pg.7]    [Pg.8]    [Pg.353]    [Pg.17]    [Pg.432]    [Pg.142]    [Pg.142]    [Pg.418]    [Pg.419]    [Pg.258]    [Pg.509]    [Pg.105]    [Pg.127]    [Pg.338]    [Pg.404]    [Pg.563]    [Pg.64]    [Pg.231]    [Pg.342]    [Pg.342]   


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