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About Gypsum
Published in Manjit Singh, Gypsum & Gypsum Products, 2023
Calcium sulphite is further treated with SO3 at reduced pH value to form soluble calcium bisulphate, Ca(HSO3)2. 2CaSO3⋅1/2H2O(s)+2SO3(g)+H2O→2Ca(HSO3)2(soln.)pH5
Basic Concepts: Separation Processes and Other Unit Operations
Published in Victor H. Edwards, Suzanne Shelley, Careers in Chemical and Biomolecular Engineering, 2018
Victor H. Edwards, Suzanne Shelley
Calcium sulfite is further oxidized to calcium sulfate dihydrate (a product known as gypsum), which precipitates out of the scrubbing liquid as a solid. If sufficiently pure, the gypsum can be captured and used to make wallboard, blackboard markers, and other products.
Resources and Sustainable Materials
Published in Stanley Manahan, Environmental Chemistry, 2017
to produce a calcium sulfite product that can be oxidized to calcium sulfate. Approximately 100 million metric tons of gypsum are mined each year for a variety of uses, including production of Portland cement, to make wallboard, as a soil conditioner to loosen tight clay soils, and numerous other applications.
ORP as slurry oxidation index and model modification in wet desulfurization system
Published in Journal of the Air & Waste Management Association, 2020
Shuang Chen Ma, Fang Xu, Defeng Li, ShuaiJun Fan, Dongsheng Xu, Caini Ma
In the wet desulfurization and oxidation process, the insufficiently oxidized product is calcium sulfite. Part of the calcium sulfite exists in the form of ions, the other part exists in the form of calcium sulfite hemihydrate (). Increased calcium sulfite hemihydrate will affect the normal crystallization of raw gypsum. The presence of calcium sulfite hemihydrate and calcium sulfate is that the in calcium sulfate will be incorporated into the calcium sulfite hemihydrate () lattice to form a solid solution. Occupying the nucleation site of calcium sulfate affects the normal growth and dehydration of calcium sulfate crystals (Fu et al. 2017).
Application of response surface methodology to absorptive separation of SO2 from its mixture with air using marble waste
Published in Chemical Engineering Communications, 2020
Lokesh Kumar, Susanta Kumar Jana, Dipaloy Datta
Reactions involved in the absorption of SO2 in the MARWAS slurry are considered to be very similar to those occurring in the desulfurization of flue gases using limestone slurry. The overall reaction of SO2 with the marble slurry in a bubble column reactor may be represented as Equation (1): The main reaction steps (Nannen et al., 1974; Ma et al., 2000) may be summarized by Equations (2–9) as follows.Mass transfer of SO2: Hydrolysis of SO2: Dissolution of CaCO3: Formation of Calcium sulfite: Calcium sulfate hemihydrate: Calcium sulfate dihydrate: Carbon dioxide: A small amount of MgCO3 present in MARWAS also reacts with the absorbed SO2:
Research on the oxidation characteristics of zinc sulfite in the zinc oxide desulfurization process
Published in Environmental Technology, 2022
Xuejiao Cao, Ting'an Zhang, Yan Liu, Weiguang Zhang, Guozhi Lv
The oxidation rate of Sample 1 increased from 3.401 × 10−5 to 4.657 × 10−5 mol·L−1·s−1 when the temperature increased from 293.15 to 323.15 K. Meanwhile, the oxidation rate of Sample 2 increased from 2.994 × 10−5 to 4.306 × 10−5 mol·L−1·s−1. Under the same temperature, the oxidation rate of Sample 1 is higher than Sample 2, which is related to the pH value of the solution in the oxidation process (Figure 7). With the increase in temperature, the oxidation rate increases. These results were similar to the effect of non-catalytic oxidation rate of magnesium sulfite [24], calcium sulfite [25] and ammonium sulfite [26].