Chemically, the main composition of coal fly ash is amorphous-phase SiO2, Al2O3, CaO, Fe2O3, and FeO. Most of these materials have high hardness on Mohs scale. Therefore, they are used as cement additive. I would like to propose an enhancement to this idea; directly depositing these fly ashes into molded plastic. The flue gas of the coal plant can melt the raw plastic and deposit its content inside it. Leaving out colder gases and no ash. Some of these ash ingredients are already been used as plastic additives. For example: Hygroscope-P is Calcium Oxide in powder form, with a purity of 95%. The function of Hygroscope-P is to absorb moisture and eliminate moisture related problems in plastics and rubber applications. Silicon dioxide is a commonly used additive in plastic films to improve clarity, compressive strength, elasticity, and aging resistance. The molded plastic then can be used in construction. Unlike aerated concrete, this plastic would be much stronger and even replace concrete blocks to carry weight.
The coal plants also produce bottom ash. These ashes stick on the bottom of the furnace and buildup over time. It is difficult to remove them as well. I propose the bottom of the furnace to have a sheet of lead. As the furnace heat up this lead would melt and attract the bottom ashes inside the furnace. All the ashes would be much lighter than lead and float on top. As long as the furnace is heated, the bottom ashes can be collected over the sea of lead. Some of these bottom ashes can also be used as plastic additive. When the furnace is shot down, lead can easily be melted and removed from the bottom of the furnace. A typical coal plant furnace has a temperature higher than lead’s melting point and below lead’s boiling point.
I developed my idea after reading this article https://www.sciencedirect.com/topics/materials-science/coal-ash.
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