102 AIR POLLUTION SOURCES
Part 1. Pollutant Emissions (continued)Pollutant types Sources and abundance Abatement and controld) Davidite—titanium ore
e) roacoelite (CaO⋅3V 2 ⋅S 3 ⋅9H 3 O)emitted. Vanadium percentages in ash can range
anywhere between 0.001 to 0.11%.
Other minor sources are the processing of steel,
cast iron and nonferrous alloys. Some
additional emissions result from the
manufacture of glass and ceramics and the
use of vanadium as a catalyst.
g. BERYLLIUM: is a light-weight,
grayish metal that has a high strength-
to-weight ratio, great stiffness and
valuble nuclear properties. A hard
metallic element which forms strong,
hard alloys with several metals,
including copper and nickel. Almost all
the presently known beryllium
compounds are acknowledged to be
toxic in both the soluble and insoluble
forms:
—beryllium sulfate soluble
—beryllium chloride
—metallic beryllium insoluble
—beryllium oxide
In concentrated form, it is found in
relatively few minerals, and there are
basically compounds of beryllium
oxide. The most important such
minerals are as follows:
Principal ore:
Beryl—3BeO⋅Al 2 O 3 ⋅6SiO 2
Beryllium is used in nuclear reactors, gas
turbines, airplane brakes, optical
devices, springs, bellows, diaphragms,
electrical contacts especially in high
voltage insulation.Major sources: Beryllium is commonly found as
an atmospheric pollutant within the confines
and in the proximity of industrial plants
producing or using beryllium substances.
Such plants engage in the extraction, refining,
machining and alloying of the metal.
b) Combustion of coals and oil containing of on
the average 1.9 ppm and 0.08 ppm of
beryllium respectively.
c) Use of beryllium as additive in rocket fuels.
d) During the 1930s, use of beryllium in
production of fluorescent lamps was a major
source of pollution.
NATURAL ABUNDANCE: Beryllium makes
up a small portion of the earth’s crust
(10 ppm) or 0.006%.1) a) Use of conventional air cleaning devices:
scrubbers, venturi scrubbers packed towers,
organic wet collectors, wet cyclones.
b) For dry processes; conventional bag collectors,
reverse-jet bag collectors, electrostatic
precipitators, cyclones, unit filters.
2) Discontinuance of the use of beryllium in
fluorescent lamp tubes.h. CHROMIUM: Chromium is a lustrous
brittle metallic element usually
occurring in compound form with other
elements. Most of the chromium ore
produced is used in the production of
stainless and austenite steels.
Chromium (Cr) is commonly known
for its use as a decorative finish in
chrome plating.Major Sources: Chromium concentrations
in urban air average 0.015 mg/m^3 and range
as high as O. 3SO mg/m^3. Although
a complete inventory of sources of ambient
chromium has not been made some
possible sources are metallurgical industry,
chromate-producing industry, chrome
plating, the burning of coal, and the use
of chromium chemicals as fuel additives,
corrosion inhibitors, pigments, tanning
agents, etc.
Natural occurrence: Elemental chromium is not
found in nature. The only important
commercial chromium mineral is chromite
(FeOCr 2 O 3 ) which is also never found in the
pure form. Most soils and rocks contain small
amounts of chromium usually as chromic
oxide (Cr 2 O 3 ). The continental crust averages
0.037% by weight, of chromium. In addition,
most animal and plant tissues contain small
amounts of chromium.Chromium air pollution usually occurs as particulate
emissions, which may be controlled by the usual
dust-handling equipment, such as bag filters,
precipitators, and scrubbers.
Chrome-plating facilities: Moisture-extractor vanes
in hood-duct systems have been used to break up
bubbles in the exhaust gases.
Mist emissions: Mist emissions from a decorative-
chrome plating tank with problems can be
substantially eliminated by adding a suitable
surface-active agent to the plating solution.C001_006_r03.indd 102C001_006_r03.indd 102 11/23/2005 9:42:42 AM11/23/2005 9: