Treatment and resource recovery from inorganic fluoride-containing waste produced by the pesticide industry.

The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste (IFCW). A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75°C, an initial pH (pHi) of 12, a 4-hr incubation time and a liquid-to-solid ratio of 40mL/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of pH and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of AlF6(3-) was restricted as increasing pH. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial pH=3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoride-containing wastes, which could be suitable for industrial applications.

[1]  G. Goldstein.  EQUILIBRIUM DISTRIBUTION OF METAL-FLUORIDE COMPLEXES , 1964 .

[2]  W. Jones,et al.  The prediction of laminarization with a two-equation model of turbulence , 1972 .

[3]  S. Ayoob,et al.  Fluoride in Drinking Water: A Review on the Status and Stress Effects , 2006 .

[4]  E. C. Beahm,et al.  A Solubility Model for Aqueous Solutions Containing Sodium, Fluoride, and Phosphate Ions† , 2000 .

[5]  K. Steel,et al.  Leaching of spent pot-lining with aluminium nitrate and nitric acid: Effect of reaction conditions and thermodynamic modelling of solution speciation , 2013 .

[6]  S. Rayalu,et al.  Fluoride in drinking water and defluoridation of water. , 2012, Chemical reviews.

[7]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[8]  K. Steel,et al.  Treatment of Spent Pot-lining with Aluminum Anodizing Wastewaters: Selective Precipitation of Aluminum and Fluoride as an Aluminum Hydroxyfluoride Hydrate Product , 2012 .

[9]  Mathew D. Halls,et al.  Nature of Hydrophilic Aluminum Fluoride and Oxyaluminum Fluoride Surfaces Resulting from XeF2 Treatment of Al and Al2O3 , 2011 .

[10]  T. O'donnell,et al.  Spent Potlining – A Hazardous Waste Made Safe , 2000 .

[11]  Héctor R. Galleguillos,et al.  Solubility of NaF in NaF + NaX + H2O (X = ClO4 and NO3) Ternary Systems and Density and Refractive Index of the Saturated Solutions at 298.15 K , 2007 .

[12]  B. Geng,et al.  A facile solution chemical route to self-assembly of CuS ball-flowers and their application as an efficient photocatalyst , 2010 .

[13]  Giorgia Spigno,et al.  Antioxidants from grape stalks and marc: Influence of extraction procedure on yield, purity and antioxidant power of the extracts , 2007 .

[14]  W. Jones,et al.  The calculation of low-Reynolds-number phenomena with a two-equation model of turbulence , 1973 .

[15]  P. Fornasiero,et al.  Nonaqueous synthesis of TiO2 nanocrystals using TiF4 to engineer morphology, oxygen vacancy concentration, and photocatalytic activity. , 2012, Journal of the American Chemical Society.

[16]  Majid Afyuni,et al.  Statistical modeling of global geogenic fluoride contamination in groundwaters. , 2008, Environmental science & technology.

[17]  Yinghao Yu,et al.  Toward greener comprehensive utilization of bastnaesite: Simultaneous recovery of cerium, fluorine, and thorium from bastnaesite leach liquor using HEH(EHP) , 2013 .

[18]  K. Steel,et al.  Recovery of fluoride values from spent pot-lining: Precipitation of an aluminium hydroxyfluoride hydrate product , 2008 .

[19]  Yingshuo Yu,et al.  Recovery of fluorine from bastnasite as synthetic cryolite by-product. , 2012, Journal of hazardous materials.

[20]  Rubén Aldaco,et al.  Fluidized bed reactor for fluoride removal , 2005 .

[21]  Á. Irabien,et al.  Calcium fluoride recovery from fluoride wastewater in a fluidized bed reactor. , 2007, Water research.

[22]  Niko Samec,et al.  Spent potlining utilisation possibilities , 2003, Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA.

[23]  G. Hota,et al.  Studies on Electrospun Alumina Nanofibers for the Removal of Chromium(VI) and Fluoride Toxic Ions from an Aqueous System , 2013 .

[24]  Rebecca K. Toghiani,et al.  Solubility in the Na + F + NO3 and Na + PO4 + NO3 Systems in Water and in Sodium Hydroxide Solutions , 2008 .

[25]  David L. Ozsvath,et al.  Fluoride and environmental health: a review , 2009 .

[26]  J. Allison,et al.  MINTEQA2/PRODEFA2, a geochemical assessment model for environmental systems: Version 3. 0 user's manual , 1991 .

[27]  A. Pulvirenti,et al.  Chemical treatment of spent carbon liners used in the electrolytic production of aluminum , 1996 .

[28]  M. Aghaie,et al.  Non-ideality and ion-pairing in saturated aqueous solution of sodium fluoride at 25 °C , 2006 .

[29]  V. C. Patel,et al.  Turbulence models for near-wall and low Reynolds number flows - A review , 1985 .

[30]  I. R. Hill,et al.  Development and validation of residue methods for the determination of the pyrethroids lambda‐cyhalothrin and cypermethrin in natural waters , 1992 .

[31]  C. Stosiek,et al.  Structure and Properties of Noncrystalline Aluminum Oxide-Hydroxide Fluorides , 2010 .

[32]  W. Haupin.  Electrochemistry of the Hall-Heroult Process for Aluminum Smelting. , 1983 .

[33]  M. Stenstrom,et al.  Environmental engineering: energy value of replacing waste disposal with resource recovery , 1999, Science.

[34]  J. Vors,et al.  Trifluoromethyl Ethers: Synthesis and Properties of an Unusual Substituent , 2009 .

[35]  F Vegliò,et al.  Recovery of valuable metals from electronic and galvanic industrial wastes by leaching and electrowinning. , 2003, Waste management.