Calcium magnesium acetate

Production

CMA can be produced from a reaction of a magnesium/calcium compound with glacial acetic acid.{{cite journal

Use as road deicer

Sodium chloride road salt costs less than $50 per ton to produce but is corrosive to metals in highway structures and increases the concentration of sodium in drinking water, which can lead to adverse health effects. Alternative deicing substances have been sought to alleviate these problems. CMA has been found to be an effective deicer and environmentally benign, though its production cost of $650 per ton is much greater than the cost of road salt. Using estimates based on New York State Data, a 1992 report in the Journal of Policy Analysis and Management concluded that $615 per ton would be saved in vehicle corrosion and that $75 per ton would be saved in aesthetic damage to roadside trees if the state highway agencies switched to using CMA as a deicer instead of sodium chloride rock salt, far outweighing its initial production cost. The report also warned that excessive federal subsidization of CMA could encourage its inefficient overuse.{{cite journal

Airport deicing

The US Federal Aviation Administration approved the use of CMA for nonaircraft deicing operations (e.g. runways, taxiways) at US airports in 1989.

Use for H₂S removal

CMA has the ability to form highly cenospheric oxide particles when heated to high temperatures, which contain thin, porous walls that are effective at capturing hydrogen sulfide from temperatures from 700 to 1100 °C up to 90%. Integrated gasification combined cycle (IGCC) systems are used to convert coal into clean, usable fuel gas which is then used to run gas turbine systems for power generation. An essential step in this conversion process is the elimination of the environmentally harmful H2S and COS from the gas that is formed from sulfur contained in the coal.{{cite journal

Desulfurization mechanism

CMA (CaMg2(CH3COO)6) decomposes around 380-400 °C to produce the following products: CaCO3, MgO, CH3COCH3, and CO2. CaCO3 further decomposes around 700 °C to CaO and CO2. A sulfidation reaction then takes place when CaO is reacted with H2S at reducing conditions in a gasifier, yielding CaS and H2O. CaS is finally reacted with O2 to produce inert CaSO4 which can then be disposed of.

References

References

1. "Calcium Magnesium Acetate".
2. "Deicing solution - US Patent 6436310 Description".
3. (1989-10-25). "Airport Winter Safety and Operations; Advisory Circular". US Federal Aviation Administration.