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Method for producing solutions of high alumina concentration by alkaline extraction.

Authors
MacMillan-RT; Jackson-J Jr.
Source
U S Pat 3 700 766 1972 Oct; :
Link
NIOSHTIC No.
10011933
Abstract
Intermittent addition of predetermined amounts of naoh to the leach solution increases the tendency toward dissolution of al and minimizes the dissolution of si and other impurities, giving a higher concentration of al2o3 in the product. The 0.5-1N naoh solution is present in a sufficient amount that the mole ratio between na in the solution and al in the shale is in the range 2- 2.5:1 (Calculated as na2o-al2o3). The ph is kept at >12 during the extraction by addition of more naoh. The mole ratio between the additional naoh and undissolved al, expressed as na2o-al2o3, is 1.3:1. Thus, <8-mesh retorted oil shale containing 2.85 pct al was stirred 20 min at 30 deg. C with 100 ml of 0.8N naoh solution (na2o- al2o3 mole ratio was 3.2:1). The extract solution was fortified with additional naoh and water and used to extract another sample of retorted shale. After 4 or more cycles the al concentration was 46.4 G/l.
Publication Date
19721001
Document Type
PA; Patent
Fiscal Year
1973
NTIS Accession No.
NTIS Price
Identifying No.
PAT 3,700,766
NIOSH Division
CPRC
Source Name
U.S. Pat. 3,700,766; Oct. 24, 1972; Chem. Abstr. 78:60,302V
State
MD
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