Crystallization of calcium sulfate dihydrate and calcium sulfite hemihydrate from synthetic flue gas desulfurization solutions: Final report

Technical Report · Wed Oct 01 04:00:00 EDT 1986

OSTI ID:7055426

Trofe, T W; Fishman, V A; Meserole, F B

The precipitation of calcium sulfate dihydrate (CaSO/sub 4/.2H/sub 2/O) and calcium sulfite hemihydrate (CaSO/sub 3/.1/2H/sub 2/O) from high, up to 240,000 mg/L, total dissolved solids (TDS) solutions was studied at 50/sup 0/C. The solutions were selected to cover a range of solution compositions of magnesium, calcium, sodium, chloride, and sulfate. Precipitation rates along with crystal habit and size changes were measured to determine the effects of these dissolved species as compared to dilute solution conditions. Calcium sulfate dihydrate (gypsum) precipitation rate was accelerated in the high TDS solutions, especially those containing chloride ion. Alternatively, calcium sulfite hemihydrate precipitation rate was found to be faster in high sulfate ion containing solutions. Sodium ion appears to produce gypsum crystals more columnar in habit while solutions containing high amounts of calcium produced very lamellar gypsum crystals. Solutions containing magnesium produced acicular gypsum crystals. Calcium sulfite hemihydrate solids precipitated from solutions containing high sulfate concentrations were rod shaped and globular as compared to the lamellar calcium sulfite hemihydrate crystals precipitated from high chloride and dilute solution liquors. Calcium sulfate-calcium sulfite solid solutions were characterized using infrared spectroscopy. Ion scavenging of Na, Mg, and Cl by gypsum and calcium sulfite solids precipitated from these high TDS solutions was also investigated. 10 refs., 21 figs., 13 tabs.

• Research Organization: Radian Corp., Austin, TX (USA)
• OSTI ID: 7055426
• Report Number(s): EPRI-CS-4811; ON: TI87920107
• Country of Publication: United States
• Language: English

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ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CALCIUM SULFATES
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
CRYSTAL GROWTH
CRYSTALLIZATION
DATA
DESULFURIZATION
DISPERSIONS
ELECTRON MICROSCOPY
EQUIPMENT
EXPERIMENTAL DATA
FLUE GAS
GASEOUS WASTES
GYPSUM
HALIDES
HALOGEN COMPOUNDS
HYDRATES
IMPURITIES
INFORMATION
INFRARED SPECTRA
MAGNESIUM CHLORIDES
MAGNESIUM COMPOUNDS
MAGNESIUM SULFATES
MEDIUM TEMPERATURE
MICROSCOPY
MINERALS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POLLUTION CONTROL EQUIPMENT
PRECIPITATION
SCANNING ELECTRON MICROSCOPY
SCRUBBERS
SEPARATION PROCESSES
SIMULATION
SODIUM CHLORIDES
SODIUM COMPOUNDS
SODIUM SULFATES
SOLID SOLUTIONS
SOLUTIONS
SPECTRA
SULFATE MINERALS
SULFATES
SULFITES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
WASTES