Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Transformation of Gibbsite to Boehmite in Caustic Aqueous Solution at Hydrothermal Conditions

Journal Article · · Crystal Growth & Design

Phase transformations among aluminum (oxyhydr)oxide minerals play important roles across a wide range of natural and industrial settings. In highly caustic aqueous solutions, uncertainty persists regarding whether solid-state or dissolution-reprecipitation pathways dominate. We explored transformation of gibbsite [a Al(OH)3] to boehmite (? AlOOH) in caustic NaOH solution at hydrothermal conditions as a function of temperature, Al(III) and NaOH concentrations, and reaction time. Comparison of detailed structural and morphological solids characterization by XRD, SEM/TEM, AFM, Raman spectroscopy, and high field 27Al MAS NMR to predictions from equilibrium thermodynamics calculations suggests the critical importance of dissolution-reprecipitation across our range of system conditions. The yield and physical properties of the boehmite product was found to be sensitive to the hydrothermal treatment temperature and the Al/OH- ratio, controlled by the loading of gibbsite with respect to NaOH. Experiments at lower Al/OH- ratios (e.g., 0.64) indicate that the dissolution of the gibbsite reaches an aqueous aluminate saturation state sufficient to overcome the nucleation barrier for boehmite. Higher Al/OH- ratios (e.g., 3.2) are found to slow the phase transformation, leaving residual unreacted gibbsite in the final product. Higher temperatures appear to improve the phase transformation rate, but also typically yield smaller sized boehmite particles. Particle morphological analyses compared to thermodynamic expectations suggest an important role of kinetics at mineral/solution interfaces, both in the gibbsite dissolution rate as well as the growth rate of boehmite nanocrystals.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Interfacial Dynamics in Radioactive Environments and Materials (IDREAM); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1577095
Report Number(s):
PNNL-SA-146423
Journal Information:
Crystal Growth & Design, Journal Name: Crystal Growth & Design Journal Issue: 10 Vol. 19
Country of Publication:
United States
Language:
English

References (45)

Aqueous high-temperature solubility studies. II. The solubility of boehmite at 0.03 m ionic strength as a function of temperature and pH as determined by in situ measurements journal July 2001
Importance of interlayer H bonding structure to the stability of layered minerals journal October 2017
Synthesis and Characterization of Boehmites Obtained from Gibbsite in Presence of Different Environments journal April 2016
Review on alumina trihydrate precipitation mechanisms and effect of Bayer impurities on hydrate particle growth rate journal December 2013
In Situ 27 Al NMR Spectroscopy of Aluminate in Sodium Hydroxide Solutions above and below Saturation with Respect to Gibbsite journal July 2018
Ionic structure in caustic aluminate solutions and the precipitation of gibbsite journal January 1998
Comprehensive Model of Synthetic Bayer Liquors. Part 3. Sodium Aluminate Solutions and the Solubility of Gibbsite and Boehmite journal September 2006
Ordered nanocrystal/silica particles self-assembled from nanocrystal micelles and silicate journal January 2006
Aluminum speciation and equilibria in aqueous solution: I. The solubility of gibbsite in the system Na-K-Cl-OH-Al(OH)4 from 0 to 100°C journal March 1992
Comparison of Raman spectra in characterizing gibbsite, bayerite, diaspore and boehmite journal January 2001
Can Cr( iii ) substitute for Al( iii ) in the structure of boehmite? journal January 2016
Size and Morphology Controlled Synthesis of Boehmite Nanoplates and Crystal Growth Mechanisms journal April 2018
The Solubilities of Gibbsite and Bayerite Below 100 °C in Near Neutral to Basic Solutions journal May 2016
A Pitzer model for the Na–Al(OH)4–Cl–OH system and solubility of boehmite (AlOOH) to high ionic strength and to 250°C journal May 2014
Assignment of the structural OH stretching bands of gibbsite journal May 2000
Regulating Multiple Variables To Understand the Nucleation and Growth and Transformation of PbS Nanocrystal Superlattices journal October 2017
Review of the Scientific Understanding of Radioactive Waste at the U.S. DOE Hanford Site journal January 2018
Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products journal November 2018
The structure of Al(III) in strongly alkaline aluminate solutions — A review journal May 2009
Acetylacetonate complexes of vanadium and molybdenum supported on functionalized boehmite nano-particles for the catalytic epoxidation of alkenes journal January 2017
The surface chemistry of Bayer process solids: a review journal January 1999
Chromium (VI) adsorption on boehmite journal March 2009
Synthesis, characterization and catalytic applications of mesoporous γ-alumina from boehmite sol journal April 2008
Aqueous high-temperature solubility studies. I. The solubility of boehmite as functions of ionic strength (to 5 molal, NaCl), temperature (100–290°C), and pH as determined by in situ measurements journal July 2001
Sunlight-curable boehmite/siloxane-modified methacrylic based nanocomposites as insulating coatings for stone substrates journal June 2016
Evidence for dawsonite in Hanford high-level nuclear waste tanks journal March 2012
Transitions in Al Coordination during Gibbsite Crystallization Using High-Field 27 Al and 23 Na MAS NMR Spectroscopy journal November 2017
Thermal stability and flame-retardancy mechanism of poly(ethylene terephthalate)/boehmite nanocomposites journal July 2010
Efficient and tuneable photoluminescent boehmite hybrid nanoplates lacking metal activator centres for single-phase white LEDs journal December 2014
Kinetics of phase transitions of gibbsite during heat treatment in air and in water vapor journal September 2007
Hydrothermal preparation and characterization of boehmites journal January 2000
The vanadate adsorption on a mesoporous boehmite and its cleaner production application of chromate journal January 2014
Fast Synthesis of Gibbsite Nanoplates and Process Optimization using Box-Behnken Experimental Design journal October 2017
Radiolytic stability of gibbsite and boehmite with adsorbed water journal April 2018
Gibbsite to Boehmite Transformation in Strongly Caustic and Nitrate Environments journal May 2003
Ab Initio Molecular Dynamics Reveal Spectroscopic Siblings and Ion Pairing as New Challenges for Elucidating Prenucleation Aluminum Speciation journal June 2018
Boehmite (γ-AlOOH) nanoparticles: Hydrothermal synthesis, characterization, pH-controlled morphologies, optical properties, and DFT calculations journal February 2012
γ-Alumina as a Support for Catalysts: A Review of Fundamental Aspects journal September 2005
Hierarchically Organized Nanoparticle Mesostructure Arrays Formed through Hydrothermal Self-Assembly journal June 2006
Different nanostructures of boehmite fabricated by hydrothermal process: effects of pH and anions journal January 2009
Hydrothermal synthesis of boehmite (γ-AlOOH) nanoplatelets and nanowires: pH-controlled morphologies journal June 2007
Synthesis of Nickel Nanoparticles Supported on Boehmite for Selective Hydrogenation of p-Nitrophenol and p-Chloronitrobenzene journal May 2010
In Situ Synthesis of γ-AlOOH and Synchronous Adsorption Separation of V(V) from Highly Concentrated Cr(VI) Multiplex Complex solutions journal July 2017
Surface Enthalpy of Boehmite journal January 2000
Predicting Surface Energies and Particle Morphologies of Boehmite (γ-AlOOH) from Density Functional Theory journal April 2018

Similar Records

Crystallization and Phase Transformations of Aluminum (Oxy)hydroxide Polymorphs in Caustic Aqueous Solution
Journal Article · Mon Jul 05 00:00:00 EDT 2021 · Inorganic Chemistry · OSTI ID:1810710

Gibbsite to Boehmite Transformation in Strongly Caustic and Nitrate Environments
Journal Article · Mon Nov 25 23:00:00 EST 2002 · Industrial and Engineering Chemistry Research · OSTI ID:805315

Radiolytic stability of gibbsite and boehmite with adsorbed water
Journal Article · Sun Apr 01 00:00:00 EDT 2018 · Journal of Nuclear Materials · OSTI ID:1421327

Related Subjects