Carbon Black
The earliest form of carbon black was probably lampblack used by
the ancient Egyptians, Indians and Chinese as a medium for writing,
for painting and even as cosmetics. The practice ensues today, usually
with the ancestral homes in rural areas, as some form of homemade
mascara.
What is carbon black?
Carbon black today is used primarily as the main reinforcing agent
for rubber. As the term denotes, the substance is a black powder
in granular form that is a by-product of the process of burning
hydrocarbons under a limited supply of air. In short, it is a process
that results to incomplete burning. The black smoke emitted from
the partial burn of hydrocarbons that is composed of extremely minute
carbon black particles are then separated from the combustion gases
to the end up with a fluffy, intense black hue.
What are the related uses of carbon black?
Carbon black finds practical use in rubber products and it is used
extensively with rubber tires. Since carbon black is used over varying
specifications, particle size, structure and surface area play a
vital role as a component of rubber, plastics and other related
products. Thus, carbon black is produced in different grades to
meet the varying needs of manufacturers. Research reveals that the
smaller particles of carbon black gives better abrasion resistance
qualities when compared to larger particles.
With rubber tires, carbon black is used as a pigment and reinforcing
shield that helps to divert heat away from the tread and belt area,
thereby reducing thermal damage and extending considerably the average
life of a tire. Carbon black is also used as a printer toner and
with some radar absorbent materials. Nevertheless, it is used in
all rubber applications where tensile strength and abrasion wear
properties are essential.
How is carbon black manufactured?
Five processes have been introduced in the market, each dependent
on the type of hydrocarbon used. The furnace black process uses
aromatic oils (crude oil base) and is burned in a reactor to separate
black carbon from tail gas and made into pellets of varying sizes
once it cools down and becomes dense.
The thermal black process on the other hand uses natural gas, but
follows the same process above. A third process called the acetylene
black process uses acetylene and undergoes a process similar to
thermal process, except that carbon black is not converted into
pellets.
The oldest known process is the lampblack process (coal tar base)
wherein heating is conducted on a cast-iron pan to produce carbon
black. The fifth process is called the bone black process. This
process though is excluded from the manufacturing category since
it does not undergo a combustion related process.
What health hazards are associated with the manufacture of
carbon black?
Three distinct substances are emitted from the manufacture of carbon
black and these are carbon sulfide, carbonyl sulfide, and hydrogen
cyanide. These substances are known to cause health hazards categorized
as chronic (long-term exposure, no cancerous effects), acute (shor-
term exposure, no cancerous effects), reproductive and developments
effects while these may also cause certain cancers.
Again, ailments are dependent on the substances concentrated in
a particular area, the frequency and duration of exposure, the character
of exposed individuals and the specific pollutant as well.
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