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Bureau of Mines / Minerals yearbook: Metals and minerals 1978-79
Year 1978-79, Volume 1 (1978-1979)

Pressler, J. W.
Gypsum,   pp. 411-422 PDF (1.6 MB)

Page 421

Table 9.—Gypsum: World production, by country —Continued
(Thousand short tons) 
Asia: —Continued 
 Vietname                       Oceania:Australia                    
 eSetimate "Preliminary. rl~~ed. NA Not available. 
' Gypsum is also produced by Romania, but production data are not available.
2lncludes anhydrite. 
4Reported figure. 
5Excludes byproduct gypsum. 
 6lncludes byproduct gypsum. (In the case of Japan, series was revised to
include estimates for byproduct gypsum, which represents virtually all gypsum
consumed during 1976-79.) 
 A new system was patented in 1978 for anchoring mine roofbolts, using a
gypsumbase cement that is cheaper than the organic resins now being used.
The key ingredient in the new cementing system is specially encased water
in waxy microcapsules. A free-flowing mixture of the droplets, plus dry gypsum-based
cement with a chemical accelerator, is packed in sausage-shaped bags, and
inserted in the hole drilled for the roofbolt. During drilling, a viscous
paste is formed that hardens in 30 seconds and provides a pull strength of
8,000 pounds per foot of hole after 5 minutes.22 
 Heyward-Robinson Co. of New York, N.Y., a member of the Alusuisse Group
of Switzerland, marketed in 1979 the hemihydrate process for the manufacture
of wetprocess phosphoric acid developed by Nissan Chemicals of Japan. The
byproduct gypsum is in such a form that it can be used directly in the production
of plaster and as a set-retarder in cement production.23 
 In 1978, Central Glass Co. of Japan began marketing a glass fiber-reinforced,
foamed gypsum product, which is expected to find its chief usage in fireproofing
walls. The product was known as Partlex, and was claimed to be light, strong,
adiabatic, and easily processed on a continuous basis. Insulation properties
were very attractive, with fire resistance greater than ordinary lightweight
concrete, and thermal conductivity only 10% of that of concrete.24 
 Japan can utilize more of its phosphogypsum and other calcium sulfate products
of chemical and utility air and water desulfurization because it concentrates
on processes that produce a much purer byproduct. The new Nissan process
(discussed above) yields a hemihydrate byproduct gypsum that can 
be recrystallized to form the dihydrate. Similarly, the Nippon Kogan Kogyo
process is a hemihydrate-dihydrate process. The Central-Prayon process also
involves a recrystallization stage, but dihydrate is initially formed and
then dehydrated to the hemihydrate form. Although both these processes are
more expensive, it means that the byproduct gypsum may be used for plaster,
wallboard, and as a set-retarder in cement.25 
 In Italy, research by the Universities of Florence and Bologna in 1978 has
indicated the beneficial results of a soil conditioner on heavy clay soils.
A soil conditioner of calcium sulfate, ferric sulfate with minor amounts
of magnesium sulfate, and ferric oxide showed increases in the permeability
of clay to air and water, decreased erosion and surface crusting and cracking,
and reduced costs of cultivation and equipment maintenance.26 
 American Cyanamid Co. and Lemco, Inc., came to an agreement in 1979 to process
and sell the byproduct gypsum produced at Cyanamid's titanium dioxide plant
in Savannah, Ga. Lemco is building a plant to produce byproduct gypsum briquettes
for the cement industry in the area.27 
' Physical sc entist, Section of Nonmetallic Minerals. 2p~ & Quarry.
V. 72, No.4, October 1979, pp. 22-23. 
Rock Products. Industry News. V. 82, No.6, July 1979, p. 
 3Tazairt, A. The New Gypsum Plant at Fleurus, Algeria. Zement-Kalk-Gips
(Wiesbaden). No. 8, August 1978, pp. 187-189 (translation of No. 6, June
 4Keller, J. Sulphur Report. V. 14, No.4, December 1978, 
 5Coope, B. Australia's Industrial Minerals. md. Miner. (London). No. 142,
July 1979, p. 41. 
 6Manos, A. Industrial Minerals of Botswana. hid. Miner. (London). No. 130,
July 1978, p. 53. 
 7Canadian Mineral Survey. Department of Energy, Mines and Resources, ottawa,
Canada. 1978, p. 74, and 1979, p. 64. 

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