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Alumina Miniplant Operations--production of Misted Raw Kaolin Feed.

Schaller JL; Hunter DB; Sawyer DL Jr.
MISSING :20 pages
The Bureau of Mines, U.S. Department of the Interior, has investigated the extraction of alumina from domestic kaolin clay by leaching with boiling 26 wt-pct hydrochloric acid. Acid leaching of crushed calcined kaolin feed yields slurries that are slow settling and difficult to filter because of the presence of fine particles generated in crushing, calcining, and leaching. Laboratory research showed that tumbling and moistening crushed raw kaolin on a pelletizing disk caused the fines to agglomerate on the surfaces of the larger particles, while the sharp edges and corners of the larger particles were rounded off. Minus 16-mesh crushed raw kaolin was misted on a 36-in-diam, 8-in-deep pelletizing disk at rates of 175 to 250 lb/hr, and was calcined in either a rotary or a fluidized- bed calciner; negligible degradation occurred. The physical properties of the misted calcined kaolin were evaluated in the leaching system of the clay-hydrochloric acid miniplant. Only minor attrition occurred during leaching, and the slurry was readily filtered on a continuous belt filter.
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
Identifying No.
RI 8712
NIOSH Division
Source Name
Page last reviewed: November 19, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division