Clean Coal: The Chemistry Of An Oxymoron
An oxymoron is a contradiction in terms. It is an adjective and noun which combine to describe a thing that can never be in logic or in nature. Clean Coal is an oxymoron.
It starts with metals. The world is full of them. As a rule metals are elements that feel that have too many electrons. They are eager to give up these electrons - in chemists terms to be oxidized. When they do this they become soluble charged atoms, ions. Metallic ions are generally highly active chemicals. They combine easily with other chemicals and produce other compounds.
In our evolution we have taken advantage of many common metals. We use sodium, potassium, calcium, iron and magnesium, to name a few, to promote and regulate the chemical reactions that make our bodies go. Without common metals we would be dead.
Unfortunately the less common metals, metals like arsenic, mercury and selenium, have much the same chemical properties as the common metals that we depend on for life. Pretending to be friends, they insert themselves into our biochemistry and wreak havoc.
In the ground the uncommon metals are, well, uncommon. They exist but they are so diluted that they pose no threat to our lives. But metals want to give up their electrons and they do so readily when water containing oxygen filters down through the ground. When they lose electrons to oxygen metals form soluble ions that move with the ground water through the water table.
One common element is more effective at capturing oxygen than metals - that would be carbon. When water containing soluble metal ions hits deposits rich in carbon the carbon combines with ionized oxygen to become carbon monoxide or carbon dioxide. The metals are left behind in insoluble forms.
Coal is rich in carbon. Coal picks up the metals that pass through it like baking soda picks up the odors in your refrigerator. Wherever it is found coal will concentrate the less common metals from the rocks that surround it. Coal will always pick these poisons and when it is burned, release them into the environment in a concentrated and deadly form.
The problems with coal ash dumps pointed out in this blog and lately in the NY Times are not accidental or confined to particular coal deposits. The metals that contaminate coals will differ in different regions but they will be there, in the coal, in the smoke released from the power plants or in the ash.
Wonks Anonymous would like to note that this phenomenon was discovered by David Love in a study of uranium deposits in Wyoming. It is reported in John McPhee's Rising From The Plains, a fine book on geology and geologists.
It starts with metals. The world is full of them. As a rule metals are elements that feel that have too many electrons. They are eager to give up these electrons - in chemists terms to be oxidized. When they do this they become soluble charged atoms, ions. Metallic ions are generally highly active chemicals. They combine easily with other chemicals and produce other compounds.
In our evolution we have taken advantage of many common metals. We use sodium, potassium, calcium, iron and magnesium, to name a few, to promote and regulate the chemical reactions that make our bodies go. Without common metals we would be dead.
Unfortunately the less common metals, metals like arsenic, mercury and selenium, have much the same chemical properties as the common metals that we depend on for life. Pretending to be friends, they insert themselves into our biochemistry and wreak havoc.
In the ground the uncommon metals are, well, uncommon. They exist but they are so diluted that they pose no threat to our lives. But metals want to give up their electrons and they do so readily when water containing oxygen filters down through the ground. When they lose electrons to oxygen metals form soluble ions that move with the ground water through the water table.
One common element is more effective at capturing oxygen than metals - that would be carbon. When water containing soluble metal ions hits deposits rich in carbon the carbon combines with ionized oxygen to become carbon monoxide or carbon dioxide. The metals are left behind in insoluble forms.
Coal is rich in carbon. Coal picks up the metals that pass through it like baking soda picks up the odors in your refrigerator. Wherever it is found coal will concentrate the less common metals from the rocks that surround it. Coal will always pick these poisons and when it is burned, release them into the environment in a concentrated and deadly form.
The problems with coal ash dumps pointed out in this blog and lately in the NY Times are not accidental or confined to particular coal deposits. The metals that contaminate coals will differ in different regions but they will be there, in the coal, in the smoke released from the power plants or in the ash.
Wonks Anonymous would like to note that this phenomenon was discovered by David Love in a study of uranium deposits in Wyoming. It is reported in John McPhee's Rising From The Plains, a fine book on geology and geologists.
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