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| Illustration fo Asbestos Cell |
The Asbestos dust is very harmful to our health - ASBESTOS is a form of mineral silica fibers are included in the serpentine group (krisotil which is magnesium silicate hydroxide with the composition Mg6 (OH) 6 (Si4O11) H2O), and amphibole of rock-forming minerals, including : actinolite, amosite (brown asbestos, cummingtonite, grunnerite), anthophyllite, chrysotile (white asbestos), crocidolite (blue asbestos), tremolite, or a mixture containing at least one of these minerals. ASBESTOS is dust particles floating in the air ASBESTOS particles that can be scattered into the air as dust in the working environment.
Here is the danger that can be caused by dust ASBESTOS for health :
- ASBETOSIS : fibrosis (which can lead to thickening and scarring of the lungs);
- Lung cancer : cancer including trachea;
- Mesothelioma : cancer in other parts of the respiratory tract such as cancer of the pleura or peritoneum;
How ASBESTOS attack the body ?
ASBESTOS dust poisoning due process is not instantaneous. Chrysotile toxins contained in the base material cumulatively ASBESTOS attack. Humans are constantly vacuuming ASBESTOS will have cancer that can cause death. ASBESTOS fibers are inhaled to get into the lungs and cause connective tissue, inflammation, and adhesions in the chest cavity.
Patients (ASBETOSIS), will initially complain of cough, weight loss and shortness of breath during activity. In fact, if continued, even at rest, shortness of breath may occur. The harm is blown continuously, even if the patient kept away from exposure to asbestos / about fifteen exposure, ASBESTOS could result in malignant pleural tumors (mesothelioma). These tumors are resistant to all kinds of therapy and the prognosis is very poor.
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| Illustration of Asbestos |
How to Make Asbestos ?
Asbestos is a general name for several types of fibrous silicate minerals. Historically, asbestos is famous for its resistance to fire and its ability to be woven into cloth. Because of these properties, it is used to make fireproof stage curtains for theaters, as well as heat resistant clothing for metal workers and firefighters. A more modern application of asbestos and chemical resistance properties utilizing fiber reinforcement to produce reinforced cement asbestos products including pipes, sheets, and shingles are used in building construction. Asbestos was also used as insulation for rocket engines on the space shuttle and as a component in electrolytic cells that make oxygen on submerged nuclear submarines. Most of chlorine to bleach, cleaners, and disinfectants manufactured using asbestos products.
The earliest use of asbestos was in about 2500 BC in what is now Finland, in which the asbestos fibers are mixed with clay to form a strong ceramic utensils and pots. The first written reference to asbestos came from Greece in about 300 BC when Theophrastus, a student of Aristotle, wrote a book called On Stones. In his book, he mentions a mineral substance not mentioned by name, which looks like wood rot, but not consumed when doused with oil and lit. The Greeks used to make lamp wick and flame retardant goods other. When the Roman naturalist Pliny the Elder statesman and write a comprehensive Natural History around 60 AD, he described this mineral and gave it fire-proof asbestinon name, meaning inextinguishable, from which we get the English word asbestos.
Though fire-resistant qualities of asbestos continues to fascinate the scientific community for hundreds of years, not until the 1800s that asbestos found many commercial uses. The first U.S. patent was issued for asbestos products in 1828 for coating materials used in steam engines. In 1868 Henry Ward Johns USA patented fire-resistant roofing materials made of jute and paper laminated together with a mixture of tar and asbestos fibers. It was an immediate success. Large-scale mining of asbestos deposits near Quebec, Canada, began in 1878 and encourages the development of other commercial uses. In 1900 asbestos has been used for making gaskets, fireproof safes, bearings, electrical cable insulation, building materials, and even filters to strain the juice.
Technological developments in the early 1900s resulted in even more usability to asbestos. Many of the early plastic materials rely asbestos fibers for reinforcement and heat resistant. Vinyl-asbestos tile floor coverings to be one of the most frequently used and remained in use until the 1960s. Automobile brake linings and clutch facings are also used in large amounts of asbestos, as did a lot of building materials. After World War II, the use of asbestos in products continues to grow. Heart surgeon using asbestos yarn to close the incision, Christmas tree decorated with artificial snow asbestos, and toothpaste brands marketed using asbestos fibers as abrasive.
The widespread use of asbestos is not without a dark side, however. Health problems associated with exposure to asbestos particles in the air have been recorded since the early 1900s, and resulted in the passage of the Asbestos Industry Regulations 1931 in the UK. In mid-1960, health problems began to surface among shipyard workers who handle asbestos insulation during World War II. In the United States, the problem reached a crisis stage in 1970, forcing the Environmental Protection Agency (EPA) to place restrictions on the use of asbestos. Although EPA revoked a ban on some types of asbestos in 1991, has been badly shaken public faith, and most manufacturers have voluntarily removed asbestos from their products. As a result, asbestos use in the United States fell from about 880,000 tonnes / year (800,000 metric tons / year) in 1973 to less than 44,000 tons / year (40,000 metric tons / year) in 1997.
In other countries, asbestos products are still widely used, especially in the construction industry. The use of asbestos in the world in 1997 is estimated around 2.0 million tonnes / year (1.8 million metric tons / year). Most of the asbestos used to make asbestos reinforced concrete products, in which the asbestos fibers are locked in concrete. Asbestos mining operations are found in 21 countries. The leading manufacturers of asbestos are Russia (formerly the Soviet Union), Canada, Brazil, Zimbabwe, China, and South Africa. Smaller deposits are found in the United States and several other countries.
Raw Materials
There are six types of asbestos : actinolite, amosite, anthophyllite, crocidolite, tremolite, and chrysolite. The first five types are known as amphiboles. They are characterized by having a very strong fiber and stiff, which makes them a serious health hazard. Amphibolic asbestos fibers can penetrate body tissue, especially in the lungs, and eventually causing tumors to grow. Six types of asbestos, chrysotile, known as serpentine. Its fiber is much softer and more flexible than amphibolic asbestos, and they do less damage to the body's tissues. All six types of asbestos consists of long chains of silicon and oxygen atoms, locked together with a variety of metals, such as magnesium and iron, to form a mustache like crystal fibers characterize this mineral.
Chrysotile is the most commonly used types of asbestos and accounts for about 98% of the worldwide production of asbestos in 1988. It is usually white, and is sometimes known as white asbestos, although it can also be yellow, gray, or greenish in color. Most of the chrysotile fibers around 0.25 to 0.50 in (6.4 to 12.7 mm) long and are usually added to the concrete mix to provide reinforcement. Only about 8% of chrysotile fibers long enough to be spun into fabric or rope. Amosite, sometimes called brown asbestos, account for about 1% of the worldwide production in 1988. It often has a brown tinge, but are also found in dark colors, and white. Coarse fiber amosite has approximately 0.12 to 6.0 in (3.0 to 152.0 mm) long. Difficult to spin fiber into fabric or rope and is mostly used as an insulating material, although the use of which is prohibited in many countries.
Crocidolite, sometimes called blue asbestos, accounts for the remaining 1% of the worldwide production. It has a bluish tinge, and the fibers are approximately 0.12 to 3.0 in (3.0 to 76.0 mm) long. Crocidolite has a very high tensile strength and excellent resistance to chemicals. One of its uses is as a reinforcement in plastics. Three other types of asbestos anthophyllite, actinolite, and tremolite-does not have significant commercial applications and rarely mined.
Manufacturing and Process of Asbestos
Asbestos deposits are found in the basement, and the ore was brought to the surface for processing using conventional mining practices. Chrysotile asbestos is usually found near the surface and can be accessed by open pit. Other asbestos deposits are found at depths varying and may require deep tunnel 900 feet (300 m) to gain access. Asbestos fibers are formed by the gradual growth of mineral crystals in the cracks, or blood vessels, found in soft rock formations. Crystals grown in the entire vein, and vein width determines the length of asbestos fibers generated. Because minerals from the surrounding rock, the chemical composition of the fibers similar to Asbestos rock. As a result of asbestos must be separated from the ore rock using physical methods, instead of chemical methods are sometimes used for processing other ores.
Here are the steps used to process ore chrysotile asbestos is commonly found in Canada :
Mining
Chrysoltile asbestos deposits are usually located using a magnetic sensor called magnometer. This method is based on the fact that the magnetic mineral magnetite is often found in close formation asbestos. Core drilling is used to determine the location of the deposits and to determine the size and purity of asbestos.
Most chrysotile asbestos operations conducted open pit mining. A series of spiral flat terraces, or benches, cut into the sloping interior holes. It is used both as a working platform and as a way to transport ore and out of the pit. Loose asbestos ore deposits of the surrounding rock with careful drilling and blasting explosives. Rock debris resulting loaded into large rubber-tired haul trucks and taken out of the mine. Some excavation operations using techniques called block caving, where part of the ore deposits are cut-up collapsing under their own weight and slid down the chute into a waiting dump truck.
Separate
Asbestos-containing ore is only about 10%, which must be carefully separated from the rock to avoid the broken fibers are very thin. The most common method of separation is called dry milling. In this method, the main separation and destruction carried out in a vacuum aspirating operations where asbestos fibers that literally sucked out of the ore. This was followed by a series of secondary separation surgery to remove stone dust and other small debris.
Ore is fed into the jaw crusher, the ore squeezed to break it up into pieces 0.75 in. (20.0 mm) in diameter or less. Crushed ore is then dried to remove moisture that may be present.
Seed that falls on the surface of 30-mesh vibrating screen, which has 0,002 openings in (0.06 mm) in diameter. As the vibrating screen, asbestos fibers loosen up to the top of the crushed ore and vacuumed away. Because of crushed ore is much more dense than fiber, only a very small rock particles could be sucked off by asbestos.
The mud is very smooth and rock particles that fall through the vibrating screen is called the channel or tailings and discarded. Pieces of crushed ore that remains on the screen is called over and moved to the next stage of processing. Crushed ore from the first screen is fed through the second crusher, which reduces the ore chunks to about 0.25 in (6.0 mm) diameter or less. Ore then fell on another 30-mesh screen vibrate and repeat the process described in steps 3 and 4.
The process of destruction and vacuum aspiration of asbestos fibers is repeated two more times. Each time the smaller the pieces of ore to asbestos fibers and then captured the remaining ore is very small so that it falls through the screen and will be discarded. Four-step process also separates the long asbestos fibers. The longest fibers are broken free from the surrounding rock crusher at first and that was sucked from the first screen. Short length fibers are broken free and was captured on each successive set of crushers and screens, until the shortest fibers caught on the last screen.
Asbestos fibers and other materials are captured from each screen was suspended in air flow and run through four separate cyclone separator. Heavy debris and dust particles of rock fell into the middle of the air flow and the rotating bottom end separator.
Air then passes through four separate sets of filters, which capture different asbestos fiber length for packaging.
Quality Control
Asbestos fibers are graded according to several factors. One of the most important factors is the length of them, because it determines which application they can be used and, therefore, their commercial value.
The most common grading system for chrysotile asbestos fibers called Quebec Standards dry classification method. This standard defines the value of nine of the fibers of Class 1, which is the longest, for Grade 9, which is the shortest. At the upper end of the scale, Grades 1 to 3 are called fiber length and ranged from 0.74 in (19.0 mm) with a length down to 0.25 in (6.0 mm) long. Grades 4 through 6 are called intermediate fibers, while the Grade 7 to 9 are called short fibers. Grade 8 and 9 fibers under 0.12 in (3.0 mm) long and loosely classified based on their density than their length.
Other factors to build quality asbestos fibers, including tests to determine the level of fiber separation or transparency, strengthen the capacity of fiber in concrete, and dust and granule contents. Special applications may require other quality control standards and testing.
Health and Environmental Effects
It is now generally accepted that the inhalation of asbestos fibers can be attributed to three serious diseases, and often fatal. Two of lung cancer, and asbestosis, affects the lungs, while the third, mesothelioma, is a rare form of cancer that affects the lining of the chest and abdominal cavity. It is also generally accepted now that the various types of asbestos, particularly amphiboles, pose a greater health hazard than chrysotile asbestos.
Finally, it is recognized that other factors, such as fiber length and the duration and level of exposure, can determine the health hazards posed by asbestos. In fact some studies have shown that some asbestos-induced lung cancers occur only when exposure above a certain level of concentration. Below the threshold, there is no statistical increase in lung cancer is found in the general population.
Although not everyone agrees with these findings, a thorough concerns about the potential adverse health effects of inhaling asbestos fibers has led to strict regulations on the amount of air possible asbestos-be at work. The regulations vary from one country to another, but they all mandate lower levels than previously found. In the United States, the Occupational Health and Safety Administration (OSHA) sets the maximum permissible exposure to long fibers of 0.005 mm at 0.2 fibers / cubic centimeter during weekdays eight hour or 40 hours of work per week.
Air asbestos levels in the general environment outside the workplace many times lower and is not considered a hazard.
Future
Asbestos is still an important component in many products and processes, although its use is expected to remain low in the United States. Exposure stringent regulation and improvement of manufacturing and handling procedures are now in place is expected to eliminate the health problems associated with asbestos.
Asbestos is a general name for several types of fibrous silicate minerals. Historically, asbestos is famous for its resistance to fire and its ability to be woven into cloth. Because of these properties, it is used to make fireproof stage curtains for theaters, as well as heat resistant clothing for metal workers and firefighters. A more modern application of asbestos and chemical resistance properties utilizing fiber reinforcement to produce reinforced cement asbestos products including pipes, sheets, and shingles are used in building construction. Asbestos was also used as insulation for rocket engines on the space shuttle and as a component in electrolytic cells that make oxygen on submerged nuclear submarines. Most of chlorine to bleach, cleaners, and disinfectants manufactured using asbestos products.
The earliest use of asbestos was in about 2500 BC in what is now Finland, in which the asbestos fibers are mixed with clay to form a strong ceramic utensils and pots. The first written reference to asbestos came from Greece in about 300 BC when Theophrastus, a student of Aristotle, wrote a book called On Stones. In his book, he mentions a mineral substance not mentioned by name, which looks like wood rot, but not consumed when doused with oil and lit. The Greeks used to make lamp wick and flame retardant goods other. When the Roman naturalist Pliny the Elder statesman and write a comprehensive Natural History around 60 AD, he described this mineral and gave it fire-proof asbestinon name, meaning inextinguishable, from which we get the English word asbestos.
Though fire-resistant qualities of asbestos continues to fascinate the scientific community for hundreds of years, not until the 1800s that asbestos found many commercial uses. The first U.S. patent was issued for asbestos products in 1828 for coating materials used in steam engines. In 1868 Henry Ward Johns USA patented fire-resistant roofing materials made of jute and paper laminated together with a mixture of tar and asbestos fibers. It was an immediate success. Large-scale mining of asbestos deposits near Quebec, Canada, began in 1878 and encourages the development of other commercial uses. In 1900 asbestos has been used for making gaskets, fireproof safes, bearings, electrical cable insulation, building materials, and even filters to strain the juice.
Technological developments in the early 1900s resulted in even more usability to asbestos. Many of the early plastic materials rely asbestos fibers for reinforcement and heat resistant. Vinyl-asbestos tile floor coverings to be one of the most frequently used and remained in use until the 1960s. Automobile brake linings and clutch facings are also used in large amounts of asbestos, as did a lot of building materials. After World War II, the use of asbestos in products continues to grow. Heart surgeon using asbestos yarn to close the incision, Christmas tree decorated with artificial snow asbestos, and toothpaste brands marketed using asbestos fibers as abrasive.
The widespread use of asbestos is not without a dark side, however. Health problems associated with exposure to asbestos particles in the air have been recorded since the early 1900s, and resulted in the passage of the Asbestos Industry Regulations 1931 in the UK. In mid-1960, health problems began to surface among shipyard workers who handle asbestos insulation during World War II. In the United States, the problem reached a crisis stage in 1970, forcing the Environmental Protection Agency (EPA) to place restrictions on the use of asbestos. Although EPA revoked a ban on some types of asbestos in 1991, has been badly shaken public faith, and most manufacturers have voluntarily removed asbestos from their products. As a result, asbestos use in the United States fell from about 880,000 tonnes / year (800,000 metric tons / year) in 1973 to less than 44,000 tons / year (40,000 metric tons / year) in 1997.
In other countries, asbestos products are still widely used, especially in the construction industry. The use of asbestos in the world in 1997 is estimated around 2.0 million tonnes / year (1.8 million metric tons / year). Most of the asbestos used to make asbestos reinforced concrete products, in which the asbestos fibers are locked in concrete. Asbestos mining operations are found in 21 countries. The leading manufacturers of asbestos are Russia (formerly the Soviet Union), Canada, Brazil, Zimbabwe, China, and South Africa. Smaller deposits are found in the United States and several other countries.
Raw Materials
There are six types of asbestos : actinolite, amosite, anthophyllite, crocidolite, tremolite, and chrysolite. The first five types are known as amphiboles. They are characterized by having a very strong fiber and stiff, which makes them a serious health hazard. Amphibolic asbestos fibers can penetrate body tissue, especially in the lungs, and eventually causing tumors to grow. Six types of asbestos, chrysotile, known as serpentine. Its fiber is much softer and more flexible than amphibolic asbestos, and they do less damage to the body's tissues. All six types of asbestos consists of long chains of silicon and oxygen atoms, locked together with a variety of metals, such as magnesium and iron, to form a mustache like crystal fibers characterize this mineral.
Chrysotile is the most commonly used types of asbestos and accounts for about 98% of the worldwide production of asbestos in 1988. It is usually white, and is sometimes known as white asbestos, although it can also be yellow, gray, or greenish in color. Most of the chrysotile fibers around 0.25 to 0.50 in (6.4 to 12.7 mm) long and are usually added to the concrete mix to provide reinforcement. Only about 8% of chrysotile fibers long enough to be spun into fabric or rope. Amosite, sometimes called brown asbestos, account for about 1% of the worldwide production in 1988. It often has a brown tinge, but are also found in dark colors, and white. Coarse fiber amosite has approximately 0.12 to 6.0 in (3.0 to 152.0 mm) long. Difficult to spin fiber into fabric or rope and is mostly used as an insulating material, although the use of which is prohibited in many countries.
Crocidolite, sometimes called blue asbestos, accounts for the remaining 1% of the worldwide production. It has a bluish tinge, and the fibers are approximately 0.12 to 3.0 in (3.0 to 76.0 mm) long. Crocidolite has a very high tensile strength and excellent resistance to chemicals. One of its uses is as a reinforcement in plastics. Three other types of asbestos anthophyllite, actinolite, and tremolite-does not have significant commercial applications and rarely mined.
Manufacturing and Process of Asbestos
Asbestos deposits are found in the basement, and the ore was brought to the surface for processing using conventional mining practices. Chrysotile asbestos is usually found near the surface and can be accessed by open pit. Other asbestos deposits are found at depths varying and may require deep tunnel 900 feet (300 m) to gain access. Asbestos fibers are formed by the gradual growth of mineral crystals in the cracks, or blood vessels, found in soft rock formations. Crystals grown in the entire vein, and vein width determines the length of asbestos fibers generated. Because minerals from the surrounding rock, the chemical composition of the fibers similar to Asbestos rock. As a result of asbestos must be separated from the ore rock using physical methods, instead of chemical methods are sometimes used for processing other ores.
Here are the steps used to process ore chrysotile asbestos is commonly found in Canada :
Mining
Chrysoltile asbestos deposits are usually located using a magnetic sensor called magnometer. This method is based on the fact that the magnetic mineral magnetite is often found in close formation asbestos. Core drilling is used to determine the location of the deposits and to determine the size and purity of asbestos.
Most chrysotile asbestos operations conducted open pit mining. A series of spiral flat terraces, or benches, cut into the sloping interior holes. It is used both as a working platform and as a way to transport ore and out of the pit. Loose asbestos ore deposits of the surrounding rock with careful drilling and blasting explosives. Rock debris resulting loaded into large rubber-tired haul trucks and taken out of the mine. Some excavation operations using techniques called block caving, where part of the ore deposits are cut-up collapsing under their own weight and slid down the chute into a waiting dump truck.
Separate
Asbestos-containing ore is only about 10%, which must be carefully separated from the rock to avoid the broken fibers are very thin. The most common method of separation is called dry milling. In this method, the main separation and destruction carried out in a vacuum aspirating operations where asbestos fibers that literally sucked out of the ore. This was followed by a series of secondary separation surgery to remove stone dust and other small debris.
Ore is fed into the jaw crusher, the ore squeezed to break it up into pieces 0.75 in. (20.0 mm) in diameter or less. Crushed ore is then dried to remove moisture that may be present.
Seed that falls on the surface of 30-mesh vibrating screen, which has 0,002 openings in (0.06 mm) in diameter. As the vibrating screen, asbestos fibers loosen up to the top of the crushed ore and vacuumed away. Because of crushed ore is much more dense than fiber, only a very small rock particles could be sucked off by asbestos.
The mud is very smooth and rock particles that fall through the vibrating screen is called the channel or tailings and discarded. Pieces of crushed ore that remains on the screen is called over and moved to the next stage of processing. Crushed ore from the first screen is fed through the second crusher, which reduces the ore chunks to about 0.25 in (6.0 mm) diameter or less. Ore then fell on another 30-mesh screen vibrate and repeat the process described in steps 3 and 4.
The process of destruction and vacuum aspiration of asbestos fibers is repeated two more times. Each time the smaller the pieces of ore to asbestos fibers and then captured the remaining ore is very small so that it falls through the screen and will be discarded. Four-step process also separates the long asbestos fibers. The longest fibers are broken free from the surrounding rock crusher at first and that was sucked from the first screen. Short length fibers are broken free and was captured on each successive set of crushers and screens, until the shortest fibers caught on the last screen.
Asbestos fibers and other materials are captured from each screen was suspended in air flow and run through four separate cyclone separator. Heavy debris and dust particles of rock fell into the middle of the air flow and the rotating bottom end separator.
Air then passes through four separate sets of filters, which capture different asbestos fiber length for packaging.
Quality Control
Asbestos fibers are graded according to several factors. One of the most important factors is the length of them, because it determines which application they can be used and, therefore, their commercial value.
The most common grading system for chrysotile asbestos fibers called Quebec Standards dry classification method. This standard defines the value of nine of the fibers of Class 1, which is the longest, for Grade 9, which is the shortest. At the upper end of the scale, Grades 1 to 3 are called fiber length and ranged from 0.74 in (19.0 mm) with a length down to 0.25 in (6.0 mm) long. Grades 4 through 6 are called intermediate fibers, while the Grade 7 to 9 are called short fibers. Grade 8 and 9 fibers under 0.12 in (3.0 mm) long and loosely classified based on their density than their length.
Other factors to build quality asbestos fibers, including tests to determine the level of fiber separation or transparency, strengthen the capacity of fiber in concrete, and dust and granule contents. Special applications may require other quality control standards and testing.
Health and Environmental Effects
It is now generally accepted that the inhalation of asbestos fibers can be attributed to three serious diseases, and often fatal. Two of lung cancer, and asbestosis, affects the lungs, while the third, mesothelioma, is a rare form of cancer that affects the lining of the chest and abdominal cavity. It is also generally accepted now that the various types of asbestos, particularly amphiboles, pose a greater health hazard than chrysotile asbestos.
Finally, it is recognized that other factors, such as fiber length and the duration and level of exposure, can determine the health hazards posed by asbestos. In fact some studies have shown that some asbestos-induced lung cancers occur only when exposure above a certain level of concentration. Below the threshold, there is no statistical increase in lung cancer is found in the general population.
Although not everyone agrees with these findings, a thorough concerns about the potential adverse health effects of inhaling asbestos fibers has led to strict regulations on the amount of air possible asbestos-be at work. The regulations vary from one country to another, but they all mandate lower levels than previously found. In the United States, the Occupational Health and Safety Administration (OSHA) sets the maximum permissible exposure to long fibers of 0.005 mm at 0.2 fibers / cubic centimeter during weekdays eight hour or 40 hours of work per week.
Air asbestos levels in the general environment outside the workplace many times lower and is not considered a hazard.
Future
Asbestos is still an important component in many products and processes, although its use is expected to remain low in the United States. Exposure stringent regulation and improvement of manufacturing and handling procedures are now in place is expected to eliminate the health problems associated with asbestos.
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