Experimental Transformation of 2M Sericite into a Rectorite-Type Mixed-Layer Mineral by Treatment with Various Salts

Abstract

Abstract--Some dehydroxylated sericites were boiled with solutions of various salts. A rectorite-like regular mixed-layer was formed when 2M sericite was treated with solution containing salts such as NaNOa, Na2SO,, CaSO4, CaC12, MgC12 and MgSO4 respectively. A random mica/montmorillonite mixed-layer was formed from 1M sericite. In order to change the 2M sericite into a regularly interstratifled mineral, they are heated to the temperature range of dehydroxylation. The formation of a regularly interstratified mineral from 2M sericite can be explained by the change in the (OH) bond direction after the extraction of the potassium ion.

Transmission and Analytical Electron Microscopic Study of Mixed-Layer Illite/Smectite Formed as an Apparent Replacement Product of Diagenetic Illite

“…Such a relation was suggested by Tomita (1974Tomita ( , 1977Tomita ( , 1978, who synthesized rectorite-like I/S and found that 2M~ and 23//2 and 1M and 1M d sericites preferentially gave rise to R 1 and random mixed-layer products, respectively. He suggested that the alteration process was in part determined by the polytypic stacking sequence through differences in OH-bonding relations between 2:1 layers.…”

Experimental Transformation of 2M Sericite into a Rectorite-Type Mixed-Layer Mineral by Treatment with Various Salts. II. Experiments Using a Magnetic Stirrer and a Centrifuge

“…Brindley and Sandalaki explain the formation of an interstratified mineral by an unmixing of the interlayer cations based on an experimental result of M6ring and Glaeser (1954). The starting composition of the experiments by Eberl and Hower (1977) was close to that of beidellite; and (3) formation from mica (Ueda and Sudo, 1966;Sudo, 1968a, b, 1971;Tomita and Dozono, 1972;Tomita, 1974Tomita, , 1977. Sudo et al (1962) explained the formation of a rectorite-type mixed-layer mineral by alternate leaching of potassium ions and hydration.…”

“…In this experiment a rectorite-type mixed-layer mineral was formed when sodium or lithium salts were used, but as reported by Tomita (1977) this kind of structure was formed when the dehydroxylated 2M sericites were boiled in the salt solutions such as MgCI2, MgSO4 and CaC12. It is considered that the interlayer potassium is removed more easily at higher temperatures than at room temperatures due to thermal vibration of the interlayers.…”

“…Experimental transformation of sericites into a rectorite-type interstratified mineral have been reported by Tomita and his colleagues using various techniques, including acid treatment of preheated mica (Tomita and Sudo, I968a,b;Tomita, 1974), treatment of sericite with molten LiNO3 (Tomita and Sudo, 1971), treatment of preheated sericite with sodium tetraphenylboron (Tomita and Dozono, 1972), and boiling with various salts (Tomita, 1977). The author has succeeded in forming a rectorite-type mixed-layer mineral from preheated 2M sericites by stirring them into the solution of various salts with a magnetic stirrer, or by washing them with various salt solutions using a centrifuge.…”

Characteristics of Clay Minerals in Podzols and Podzolic Soils

“…These 1M and 2M types show the monoclinic crystalline with one and two unit layer respectively. Tomita and Sudo (1 968) and Tomita (1977) conducted experiment on the transformation of dioctahedral mica minerals with acids and salts, and concluded that 1M sericite was degraded to mica-montmorillonite randomly interstratified minerals although 2M sericite was transformed to regularly interstratified minerals. Based on their theoretical and experimental findings, the 1 M-type dioctahedral mica minerals were degraded directly to smectite and/or vermiculite along with the release of potassium and the hydration in the interlayer position under the highly acid conditions in eluvial horizon.…”