THE EFFECT OF ELECTROLYTES ON SOME PROPER‐ TIES OF CLAYS.¹

Abstract

Introduction.One of the sources of loss in the manufacture of clay products, especially of the larger kind, chemical stoneware, glass pots, etc., is due to the lack of strength of the clays in the dry state and at the burning temperatures. Suficient strength to resist the shocks and strains of handling in the green state is necessary. A t certain periods in the burning the ware loses strength and is liable to warp, crack, or break, causing large kiln losses. The natural remedy would be to improve the strength of the clay body by artificial means or to introduce stronger clays.The effect of the addition of organic compounds tc clays has been studied by Acheson,2 Minton3, Seger and Cran~er,~ and K~e r n e r ,~ and it has been shown that the strength of the clays can be increased by the addition of gallo-tannic acid, catechu, straw emulsion, dextrine, or starch.The effect of the addition of alkalies and acids on the volume shrinkages of clays in the plastic state has been reported by Bleininger and Fulton,6 and Kerr and Fulton,' but our information as to the effect of these electrolytes on the strength of clays is meagre. Bleiningers has reported that cast bodies containing alkalies may be stronger than bodies not containing alkalies. The writer9 has noted that the rate of disintegration in water is much slower for the deflocculated than for the flocculated clays.

Colloidal processing: enabling complex shaped ceramics with unique multiscale structures

“…In the 100 years since the first paper in the Journal of the American Ceramic Society related to colloidal processing science was published, advances in the field have already brought us to unexpected places, techniques, concepts, and designs. We are confident that colloidal processing will continue to grow to include other material classes, to be instrumental in the development of smart technologies and to enable new functionalities and manufacturing approaches.…”

“…These initial studies then led to more detailed work by Schurecht published 100 years ago in the first volume of the Journal of the American Ceramic Society, which quantified the strength of wet clays by performing three‐point bend tests and determining the resulting modulus of rupture. The clay suspensions were modified with varying amounts of electrolytes including sodium hydroxide, sodium silicate, sodium carbonate, calcium hydroxide, tannic acid, and sulfuric acid.…”

“…The clay suspensions were modified with varying amounts of electrolytes including sodium hydroxide, sodium silicate, sodium carbonate, calcium hydroxide, tannic acid, and sulfuric acid. Schurecht reported that alkalis, such as the sodium hydroxide that produced the strongest air‐dried clay, appeared to have dispersed the clay particles resulting in a fine grain structure when examined with a microscope. In addition, the strength imparted by the addition of sodium hydroxide was translated to the fired clay that was also reported as having the greatest strength of all the modified clays.…”

“…In addition, the strength imparted by the addition of sodium hydroxide was translated to the fired clay that was also reported as having the greatest strength of all the modified clays. Apart from the difficulty of molding clays dispersed with NaOH, Schurecht's work revealed these clays also exhibited the highest densities and lowest percent porosity of all the acids and alkalis tested. A patent filed some years later by Bleininger laid claim to the use of alkalis and acids to control the plasticity and formability of clays, yet the true understanding of the surface charge imparted onto the particles by such additions was some years off.…”

Review: Variability, Non-uniformity and Complexity: From Product to Process

“…Even if a single species is received in the mill, it might be collected from different parts of the forest lands, which may contain juvenile and mature woods, for example. These woods normally have different bre lengths and cell wall geometries (e.g., bril angles in S2 wall), and thus result in different properties in end-products [3][4][5][6][7]. This variability is only the very beginning of the entire manufacturing chain.…”