We’ve previously written about the dangers of mercury in the environment, in How is Mercury in the Air Monitored?. Mercury is a naturally-occurring chemical element found in rock in the earth’s crust, including in deposits of minerals, coal, iron ore, and limestone. But mercury exposure at high levels is harmful to the environment and one’s health.
According to the US EPA, mercury becomes a problem for the environment when it it is released from rock and ends up in the atmosphere and in water. Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages.
The burning of coal, oil and wood as fuel can cause mercury to become airborne, as can burning wastes that contain mercury. There are multiple potential sources of mercury emissions from kilns at cement plants. The primary source is limestone, the main constituent of the raw material. Other smaller sources of mercury emissions include sand and iron ore. Coal, which is often used to heat the raw material, contains mercury which becomes a part of the plant’s emissions. Mercury is also a part of dust captured in the Air Pollution Control Device, which is reintroduced to the cement kiln. Because the cement process is a harsh operating environment for stack monitoring, with high temperatures, moisture and dust in the flue gas, sudden changes in the process can cause large variations in mercury emissions.
Because of industry regulations, waste incinerators, cement producers, and coal-fired and combustion power plants (which are also a major source of mercury in the air) are utilizing the latest technology to help monitor and reduce emissions, reduce public risk, and protect the environment. Read more about this threat to the environment and the technologies used to monitor mercury emissions on our sister blog, How is Mercury Monitored in a Cement Kiln?