Ralph E. Grim

Quantitative Estimations of Clay Minerals by Diffraction Methods

ABSTRACT The clay mineral components of Recent sediments and soil materials exhibit structural attributes unlike those of many so-called standard clay materials. The interpretation and significance of some of these is discussed in detail. Factors involved in analyzing these materials quantitatively are considered and a general procedure outlined.

RELATION OF THE COMPOSITION TO THE PROPERTIES OF CLAYS

Most clays are composed essentially of minute particles of one or more of the clay minerals of which the kaolinite, montmorillonite, and illite groups are most important. The clay minerals occur in flake-shaped particles, possess base-exchange capacity, and exist in or are reducible to extremely small grain sizes on working with water. Different clay minerals possess these properties in varying degrees. The clay mineral component is the chief factor determining the properties of a clay. In general, plasticity and bond strength caused by the clay minerals decrease in the following order: montmorillonite, illite, and kaolinite. In many clays, the plasticity and bond strength mainly result from the presence of the montmorillonite minerals or some members of the illite group, although these constituents may compose only minor amounts of the clay. The influence of the clay minerals on other properties is considered. The green properties of clays are also related to the character of the exchangeable bases carried by the clay minerals. The fundamental reasons for the differences in properties resulting from different mineral constituents and various exchangeable bases are considered. The properties of clays are related further to the effective size-grade distribution developed in actual use which frequently differs from the size-grade obtained by mechanical analyses.

SOME CLAY‐WATER PROPERTIES OF CERTAIN CLAY MINERALS*

Computed values are given for the thickness of the water film adsorbed on the surfaces of the various clay minerals when clays composed of such minerals develop specific plastic characteristics. Based on such values, the following concept of clay-water relationships is presented: The dominant factor determining the plastic properties of clays is the rigidity of the water held on the surfaces of the clay minerals, and the point of beginning of the transition of completely rigid water to liquid water is marked by great changes in such properties. Each type of clay mineral seems to have a characteristic ability to stabilize water, and the exchangeable ions also exert an influence. The reaction between water and kaolinite or halloysite may require considerable time so that there is frequently a time lag after mixing clays composed of such minerals before the plastic properties are fully developed. Application of the foregoing concept in the fields of geology, ceramics, and soil mechanics are suggested.

Application of clay mineral technique to Illinois clay and shale

INTRODUCTION The method of analysis herein described is being used in Illinois in an investigation of the mineral constituents of various soils, clays, and shales. The results are to be published later, but sufficient progress has already been made to warrant a statement of the technique developed. The need for a method for the accurate identification and classification of mineral particles of colloidal size has long been a problem.[1][1] Various methods have been used in attempting to solve the problem, but in investigating the argillaceous sediments of Illinois, it was found that even the most recently described techniques do not entirely suffice when the colloidal particles contain several minerals. Although this inadequacy has not been entirely surmounted for all argillaceous materials, it is felt that the technique herein described permits a more complete and more accurate mineral identification than has been possible heretofore. A clay and a shale from Illinois . . . [1]: #fn-2

The Petrographic Study of Clay Minerals--a Laboratory Note

ABSTRACT The individual clay mineral particles that compose clayey sediments are usually too small to permit their optical properties to be determined. A technique is described for obtaining aggregates of clay mineral particles in which all the individual particles have about the same optical orientation so that the optical constants of the clay mineral can be measured easily and accurately. The problem presented by fine calcite, which masks the optical constants of the clay mineral and of which the removal is difficult without altering the clay mineral, is met by an improved method for eliminating fine calcite from calcareous sediments.

Heavy Minerals in Illinois Sands and Gravels of Various Ages

Studies of the heavy minerals in 9 samples of Recent sand, 18 samples of Glacial sand, and 8 samples of Cretaceous sand reveal that the Glacial sands and the Recent lake and river sands derived from glacial deposits are characterized primarily by hornblende, pyroxenes, garnet and magnetite, usually in comparatively large amounts, with minor amounts of epidote, tourmaline, and zircon. Noteworthy also is the uniformity of the heavy mineral assemblages of the Pleistocene and Recent sands with reference to mineralogic composition and relative abundance of the different mineral grains. It suggests a similar ultimate source area for all these deposits. The suite of minerals indicates that igneous rocks were dominant in the source area. The heavy mineral assemblages of the Cretaceous sands are very different from those of the Glacial sands or of the lake and river sands derived from Glacial deposits and are characterized primarily by kyanite, muscovite, tourmaline, zircon, staurolite, and rutile, with minor amounts of ilmenite, leucoxene, and sillimanite. The rare earth minerals, monazite and xenotime, although present only in small amounts, are consistently found in the Cretaceous sands and only very occasionally found in the non-Cretaceous sands. The source area for these sediments differed from the source of the Pleistocene and Recent sands. Metamorphic rocks such as schists and slates are indicated by the abundant stress minerals.

PETROGRAPHIC AND CERAMIC PROPERTIES OF PENNSYLVANIAN SHALES OF ILLINOIS

Coal Measures shales, which are widespread in Illinois, are used extensively as a ceramic raw material. Ceramic determinations are given for a large number of shales to illustrate the wide range in their properties. The mineral composition, base-exchange capacity, and textural characteristics are presented for the same shales, and the relation of these characteristics to the ceramic properties of the shales is analyzed.