Chemistry of soil minerals. Part V. Low temperature hydrothermal transformations of kaolinite

Abstract

R a w kaolinite has been investigated as a possible starting material for low-temperature hydrothermal growth of zeolites and felspathoids. It proved to be convenient and versatile in this role, being readily transformed into a range of known and new zeolites and salt-inclusion felspathoids with a Si/AI ratio around 1 .O, some of which have novel properties. Experiments were conducted at 80" using aqueous solutions of lithium, sodium, potassium, rubidium and caesium hydroxides, sometimes in the presence of additional alkali-stable anions. Some quantitative aspects of the recrystallization reactions are discussed, as are the chemical and physical properties of representative compounds of each type synthesized.

Localization of water in hexasodium hexakis(aluminosilicate)–deuterium oxide (1/8), Na6[AlSiO4]6.8D2O. A neutron powder diffraction Rietveld profile analysis at 10 K

“…The structure should show close resemblance to that of the mineral sodalite Na 8-[AISiO4]6CI 2 (Pauling, 1930;L/Sns & Schulz, 1967). Barrer & White (1952) and Barrer, Cole & Sticher (1968) revealed the solid-solution character of the hydrosodalites (hydroxysodalites) with limits of composition Nas_x[AISiO4]6(OH)E_x.nH20, 0 _< x < 2, 0 5 n_<8.…”

Use of the Additive Based on Amorphous Silica-Alumina in the Adhesive Dry Mixes

“…Previous studies have confirmed the efficacy of synthetic zeolites as a modifying agent for cement and lime dry mixes [9][10][11][12][13][14][15][16][17][18][19].…”

Radionuclide and Contaminant Immobilization in the Fluidized Bed Steam Reforming Waste Product

“…In addition, rare earth nephelines are known, e.g. NaYSiO 4 , Ca 0.5 YSiO 4 , NaLaSiO 4 , KLaSiO 4 , NaNdSiO 4 , KNdSiO 4 , and Ca 0.5 NdSiO 4 , where the rare earth substitutes for Al in the structure (Barrer, 1982). A sodium-rich cubic structured nepheline with excess Na is also known, e.g.…”

“…Although neither Cs nor Rb sodalites have been identified as phase pure end members, Cs and Rb are tolerated in the sodalite structure (Deer et al, 1963;Deer et al, 2004). In addition, non-naturally occurring Zeolite-A structures are known to form from the reaction of CsOH and RbOH with kaolin clay (Barrer et al, 1968).…”

“…(b) Higher valent anionic groups such as AsO4 3-and CrO4 2-form Na2XO4 groups in the cage structure where X= Cr, Se, W, P, V, and As (Barrer, 1982). …”