engleski

Model experiments with CaO, MgO and calcinated dolomite for fluoride removal in a wet scrubbing system with sea water in recirculation

Fluoride removal was studied from saline waters using CaO, MgO and calcined natural dolomite (all fired at 1273 K), as an alternative for lime slurry neutralization process. Fluoride in the form of HF was added to sea water, saline groundwater or distilled water from 50 to 158 mg dm−3. The amount of added CaO, MgO and CaO·MgO varied from 80 to 560 mg dm−3. Concentrations of soluble fluoride, calcium, magnesium and pH were determined in supernatant. X- ray diffraction was used to identify the precipitated solids. All three processes show very good removal of fluoride from saline water, within 90 min designed for technological process (soluble fluoride varied from 5 to 25 mg dm−3). It can be assumed that fluoride is either present in the form of an amorphous salt or is incorporated into the crystal lattice of one of the identified solids (CaCO3, CaCO3·H2O, Mg(OH)2, Mg2SiO4).

aluminium production ; calcium fluoride ; calcium oxide ; calcite ; calcined dolomite ; removal of flyoride ; hydrocalcite ; magnesium oxide ; sea water ; wet scrubber

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