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U.S. Department of Energy
Office of Scientific and Technical Information

Phosphohemihydrate process for purification of gypsum

Patent ·
OSTI ID:7101269
A wet process for producing phosphoric acid and phosphohemihydrate by acidulation of phosphate rock. A strong phosphoric acid is obtained with concomitant production of an improved calcium sulfate that is extremely low in radioactivity by operation in Region II for shorter time so as to produce small sized hemihydrate particles, then hydration of a substantial proportion but less than all of the hemihydrate to coarse gypsum substantially free of radioactivity in a dilute acidic aqueous slurry at a temperature and P/sub 2/O/sub 5/ concentration selected so as to be within Region I of FIG. 1 and having a substantial weight proportion of coarser gypsum particles that are substantially free of radioactivity.
Assignee:
United States Gypsum Co., Chicago, IL
Patent Number(s):
US 4424196
OSTI ID:
7101269
Country of Publication:
United States
Language:
English