The adsorption of cations on basal surfaces where negative charges occur, possibly as a result of isomorphous replacement within the structure, and/or adsorption on mineral surfaces where unsatisfied charges may occur often where there are incomplete coordination units. Surface adsorption is common on the basal oxygen atom plane of the 2:1 layer of phyllosilicates. Edge adsorption predominates in kaolin-type phyllosilicates having 1:1 layers (modified from O’Bannon, 1984).
See suspension.
Aesthetic medicine is a discipline involving all medical methods, including the application of materials such as some clays, to skin for cosmetic purposes (e.g., to tighten skin, add/change color, stimulate circulation, or reduce a scar ). Such procedures are generally non-invasive or minimally invasive. Procedures that are non-invasive or minimally invasive are typical.
Cf., active principle, antibacterial clay, geotherapy, healing clay, medicinal clay, pelotherapy
An obsolete, local term for a fibrous talc from New York State, USA; or for pyrophyllite from China (also obsolete).
An obsolete term for pyrophyllite or a mixture with dominant pyrophyllite.
Ageing refers to:
a) a process where the physical properties, for example the rheology, of wet clay are improved by allowing the clay to sit undisturbed for a period, sometimes for years but more often for days or months, to allow the water to become more homogeneously distributed or to promote the growth of microorganisms. An improvement in plasticity by ageing is important for pressing and drawing of the clay for commercial production of ceramics.
Syn., aging, maturation;
b) in soil mechanics, aging is also referred to the process of secondary consolidation or drained creep.
Cf., drained creep, secondary compression
See flocculation.
See flocculation.
See ageing.