Research on the thermal decomposition and kinetics of byproducts from MgO wet flue gas desulfurization

Reutilization of MgO Byproducts from the Calcination of Natural Magnesite in Dry Desulfurization: A Closed-Loop Process

“…The water and CO 2 emissions were also confirmed by MS (figures not shown). Thus, the mass loss steps were ascribed as (i) water loss (<200 °C), (ii) magnesium sulfite decomposition to MgO and SO 2 (200–530 °C), (iii) CO 2 release from MgCO 3 decomposition (500–650 °C), (iv) CO 2 release from CaMg­(CO 3 ) 2 decomposition (600–900 °C), and (v) CaCO 3 decomposition along with the desulfation of calcium sulfite (900–1000 °C), as reported elsewhere. ,− All of the mass loss steps corresponded to the compounds of the raw byproduct that remained in the spent sorbent. The decomposition temperature of magnesium sulfite (maximum peak at 340 °C) was lowered by the reducing conditions promoted by CO emitted from the incomplete combustion of the remaining petcoke, the fuel used during the industrial calcination process. , The final amount of CaCO 3 was a balance between CaCO 3 present in the raw sorbent, CaCO 3 formed by reaction of calcium hydroxide and CO 2 , and CaCO 3 that disappeared after reacting with SO 2 , as reported elsewhere for a desulfurization process with calcium hydroxide. , The preceding was confirmed by Figure b, where all of the mass loss steps before 800 °C could be described as in Figure a, although the mass loss step attributed to the decomposition of calcium sulfite was not detected and a mass loss step at 1300 °C with SO 2 release (63.96/A) was observed instead; this mass loss was attributed to SO 3 (SO 2 + 1/2O 2 ) released from calcium sulfate formed by oxidation of CaSO 3 (or partially by the reaction of CaCO 3 and SO 2 released) in the TG process in an air atmosphere.…”

Sustainable Calcination of Magnesium Hydroxide for Magnesium Oxychloride Cement Production

“…As is well known, it is utilized in many industries ranging from refractory applications (Sako et al 2012), in agriculture as a plant nutrient (Antonini et al 2012), to wastewater treatment as an alkaline source to remove heavy metals (Purwajanti et al 2015). It is also utilized in the manufacture of rubber and plastics, as well as in flue gas desulfurization for air pollution control (Gu et al 2010;Marković et al 2013;Yan et al 2014).…”

A novel resource utilization method using wet magnesia flue gas desulfurization residue for simultaneous removal of ammonium nitrogen and heavy metal pollutants from vanadium containing industrial wastewater

“…But the oxidation of the magnesium sulte should be prevented by adding an oxidation inhibitor during the FGD process because of the higher thermal decomposition temperature of magnesium sulfate. 8,9,15,16 Nowadays, the vast majority of the wet magnesia FGD residue is casually stacked without further treatment or discarded aer forced aeration oxidation, and this is attributed to the high investment associated with the equipment for the treatment process and the low economic benet of recycled products. 7 The wastewater discharged from the sodium roasting vanadium extraction technology is complex, hard to degrade biochemically, has a high pollutant gas concentration, and is a highly hazardous acidic wastewater containing high concentrations of vanadium (V), hexavalent chromium [Cr(VI)] and ammonium nitrogen (NH 4 -N).…”