Crystallization of beta-FEF3.3H2O in mixtures of nitric and hydrofluoric acid
2005 (English)In: VDI-Berichte 1901, V D I Verlag GmbH , 2005, 17-22 p.Conference paper (Refereed)
The solubility of β-heh 3·3H 2U has been measured in solutions with a range of different hydrofluoric acid concentrations (2, 4 and 6 mol/kg) and constant nitric acid concentration (3 mol/kg) in order to calculate a solubility constant applicable at the present ionic strength and temperature. Crystal growth of β-FeF 3·3H 2O has been measured in 3molal hydrofluoric acid and 3molal nitric acid solutions at 50°C by performing seeded isothermal desupersaturation experiments (1 < S < 3). The supersaturation was recorded by taking out solution samples which were analysed for total iron concentration with inductively coupled plasma atomic emission spectrometry (ICP-AES). The true supersaturation driving force was estimated by a proper speciation to account for the complexation, using the software SSPEC and relevant stability constants. Parameters of a desired growth rate equation were estimated by fitting the supersaturation balance equation directly to the supersaturation measurements. The results show that growth of β-FeF 3·3H 2O follows a parabolic rate law (g= 2,0 ±0,2). The growth rate at S= 2 was found to be 4,6×10- 11 m/s (50°C). The growth order and the low value of the growth rate suggest that the rate is surface integration controlled.
Place, publisher, year, edition, pages
V D I Verlag GmbH , 2005. 17-22 p.
, VDI - Berichte, ISSN 0083-5560 ; 1901
Atomic emission spectrometry, Isothermal desupersaturation, Solution samples, Supersaturation balance
IdentifiersURN: urn:nbn:se:kth:diva-28455ScopusID: 2-s2.0-27344433300OAI: oai:DiVA.org:kth-28455DiVA: diva2:387479
16th International Symposium on Industrial Crystallization 11th - 14th September 2005, International Congress Center dresden/Germany
QC 201101142011-01-142011-01-142014-04-07Bibliographically approved