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Ten-Cycle Bench-Scale Study of Simplified Clay-Hydrogen Chloride Process for Alumina Production.

PB95217071

Publication Date	1995
Personal Author	Shanks, D. E.
Page Count	26
Abstract	This research simplified an earlier hydrogen chloride (HC1) leach-sparge process developed by the U.S. Bureau of Mines to recover reduction-grade alumina from domestic kaolin clay. Improvements were made by decreasing the initial leaching acid concentration from 25 to 20 pct, decreasing the leaching time from 1-2 h to 15-30 min, eliminating the solvent extraction step for Fe removal, and eliminating the step to recover the Al content of the bleedstream circuit. A 10-cycle bench-scale experiment of the simplified process showed that the FeCl3 concentration built up to 9.3 g/L in the recycle stream. This did not interfere with any of the unit operations or final alumina product purity because Fe forms stable soluble chloride complexes when sparged with HC1 and is easily washed from the large aluminum chloride hexahydrate (ACH) crystals. The reduced leaching time and acid concentration did not decrease Al extraction.
Keywords	Aluminum oxide Materials recovery Kaolin Leaching Clay minerals Solvents Extraction Hydrochloric acid Concentration(Composition) Crystallizers Hydrogen chloride
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries 99B - Industrial Chemistry & Chemical Process Engineering
Corporate Authors	Bureau of Mines, Reno, NV. Reno Research Center.
Document Type	Technical Report
Title Note	Rept. of investigations/1995.
NTIS Issue Number	199516

Ten-Cycle Bench-Scale Study of Simplified Clay-Hydrogen Chloride Process for Alumina Production.

Ten-Cycle Bench-Scale Study of Simplified Clay-Hydrogen Chloride Process for Alumina Production.
PB95217071

Publication Date	1995
Personal Author	Shanks, D. E.
Page Count	26
Abstract	This research simplified an earlier hydrogen chloride (HC1) leach-sparge process developed by the U.S. Bureau of Mines to recover reduction-grade alumina from domestic kaolin clay. Improvements were made by decreasing the initial leaching acid concentration from 25 to 20 pct, decreasing the leaching time from 1-2 h to 15-30 min, eliminating the solvent extraction step for Fe removal, and eliminating the step to recover the Al content of the bleedstream circuit. A 10-cycle bench-scale experiment of the simplified process showed that the FeCl3 concentration built up to 9.3 g/L in the recycle stream. This did not interfere with any of the unit operations or final alumina product purity because Fe forms stable soluble chloride complexes when sparged with HC1 and is easily washed from the large aluminum chloride hexahydrate (ACH) crystals. The reduced leaching time and acid concentration did not decrease Al extraction.
Keywords	Aluminum oxide Materials recovery Kaolin Leaching Clay minerals Solvents Extraction Hydrochloric acid Concentration(Composition) Crystallizers Hydrogen chloride
Source Agency	Bureau of Mines
NTIS Subject Category	48A - Mineral Industries 99B - Industrial Chemistry & Chemical Process Engineering
Corporate Authors	Bureau of Mines, Reno, NV. Reno Research Center.
Document Type	Technical Report
Title Note	Rept. of investigations/1995.
NTIS Issue Number	199516