NIOSHTIC-2 Publications Search
Structural Location and Role of Hydrogen Ions in Kaolinite and Its Products in Aluminum Removal.
Young-RA; Suitch-PR; Moody-WE
For Reference Only At Bureau Libraries :24 pages
The objectives of this program were to (1) determine the mechanistic details by which the structural locations and ordering of the hydrogen ions in kaolinite affects its crystallinity, solubility, viscosity, processing, and use characteristics; (2) determine the intracrystalline mechanisms involved in the extraction of aluminum; and (3) better determine and control the characteristics of the siliceous byproducts of aluminum extraction in order that useful products may be created from them. X-ray and neutron powder diffraction data and the rietveld method were used to refine the crystal structure of kaolinite specimens. The positions of the nonhydrogen atoms in dickite were similarly re-refined from x-ray powder data. In kaolinite, the rotation in the tetrahedral sheet is 7(1)deg. The two inner hydroxyl o-h bonds are differently oriented; one points into an octahedral vacancy and the other points away. All six of the inner surface hydrogen atoms appear to be nearly equally involved in the hydrogen bonding between kaolinite layers in kaolinite. The process of dehydroxylation of the kaolinite was followed in detail with x-ray diffraction techniques. Dehydroxylation began at about 325 deg to 350 deg c and was more than half completed at 465 deg c. It was found that "half completed" means that one-half of the initial sample was completed dehydroxylated while the other one-half was not, retaining all details of its kaolinite structure.
CP; Final Contract Report;
For Reference Only At Bureau Libraries
Georgia Inst. of Tech.
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division