CLAYS 293 
 
published." The article also discusses the physiochemistry of the three
main
paint components: pigment, medium (binder or vehicle), and solvent (thinner).
Special tables listing typical analyses for paint-grade kaolins as well as
the current British standard specifications for china clay extenders in paint
were also included. An interesting feature of the article was the wide range
of subStitutability possible in pigment material, chiefly to reduce raw material
cost yet still capable of producing a high-quality competitive paint. A similar
treatment was afforded the English cosmetics mdustry'3 A highlight of this
work was the technical specifications for face powder kaolins and special
clays used for their absorbing, degreasing, thixotropic, and pigment suspendingproperties.

 An indepth review was published of major mdustrial minerals, including bentonite
kaolin, plastic, and fire clays currently mined and processed in the Federal
Republic of Germany." The review covered the geology, mineralogy, output,
production flowsheets, and consumption of clays by the domestic refractory,
ceramics, glass, and paper industries. A special feature of the article was
a table on major areas of application for crude, acid, alkaline, and organically
activated bentonites. A similar detailed treatment, but more heavily oriented
toward a geological, mining, and mineralogical approach, was afforded sepiolite,
attapulgite, bentonite, and to a lesser degree, kaolin, produced in Spain."
Tables highlighting the physical and chemical properties of foundry and gelling
bentonite and ceramic grades were also listed. 
 The geological and production aspects of the industrial minerals exploited
in California," Greece,4' and Jamaica" were discussed briefly in
other publications.
The California paper stressed the mining and production flowsheets for the
lone kaolin, and the Greek work targeted bentonite and kaolin production.
A highlight of the latter paper was an industrial minerals map of Greece
depicting the major bentonite and kaolin production sites, largely on the
islands of Lesvos and Milos. The Jamaican article, strictly an overview,
dealt with its 16 major clay deposits, mostly bentonite, 
kaolin, and common clays, currently under investigation for ceramic and structural
product manufacturing. 
A concise but detailed study was published on the Chinese bentonite industry.4~
The article provides the latest information on Chinese bentonite resources,
exploration, mining, processing, physical and chemical properties, research,
and marketing goals. The Chinese bentonites are widely distributed, and China
is regarded as being second only to the United States as a worldwide source
of bentonites. Chinese specifications with typical analyses for sodium-exchanged,
organoclad drilling-mud and foundry and iron ore grades of bentonite were
listed and discussed. A case study of the Heishen open pit and Linan underground
mines was included. 
 The differences in thermal decomposition of sodium and calcium bentonites
and their role in foundry sand bonding during metal casting was explored
in detail." The data showed that bentonite burnout and consumption depend
on many factors, but the sand-to-metal ratio, cooling time, and time of casting
in the mold emerge as the most important. US. sodium and calcium bentonites
were used throughout the investigation as the reference base and/or standard
material. The technical rationale for the past, present, and future industrial
minerals usage by the U.S; drilling industry was published.~' The paper stressed
the indispensability of bentonite gelling clays and new material usages,
such as organoclays, in oil-based drilling fluids. 
 The preferential absorption of selected 
environmental toxins, such as dioxin, by modified smectites or bentonites
was researched." The investigation showed that smectites bound to hydroxy
aluminum are three times more effective than activated carbon, at present
the most commonly used industrial sorbent, in removing toxins from industrial
effluents. Future work should lead to additional modified clay systems capable
of removing other chemical pollutions and toxins. Clays have the advantage
of being a relatively inexpensive commodity compared with other industrial
and reagent chemicals, such as activated carbon and zeolites.