The removal of iron from aluminum chloride leach liquor by solvent extraction.
Sorensen-RT; Amey-EB III
Boulder City, NV: U.S. Department of the Interior, Bureau of Mines, RI 8560, 1981 Sep; :1-28
As part of its mission to maintain an adequate supply of minerals to meet national needs and maximize mineral production from domestic sources, the Bureau of Mines is investigating the recovery of alumina by hydrochloric acid leaching of kaolinitic clay. Most iron impurities are leached from the clay along with the alumina and must be removed before or during crystallization to aluminum chloride hexahydrate. The thermal decomposition step then provides an alumina product of acceptable iron analysis. Mini-plant studies of a Bureau-developed solvent extraction technique, using a Tertiary amine in kerosine diluent, have demonstrated that the iron content in aluminum chloride leach liquors can be reduced to levels of less than 0.007 wt-pct (7 ppm), expressed as Fe2O2. Entrained and dissolved organic matter in the purified pregnant leach liquor from the solvent extraction circuit can be reduced to less than 2 ppm by using a fabric-packed coalescer and subsequent activated carbon treatment. Investigators discovered that a steady buildup of zinc accumulated in the solvent phase within the extraction circuit, proportional to the amount of leach liquor treated. The solvent phase zinc analysis increased by 0.01 wt-pct ZnO for each 1,000 gal of pregnant leach liquor purified.
Aluminum halides; Aluminum oxide; Iron; Leaching; Liquids; Solvent extraction; Solvents; Tertiary amines
IH; Report of Investigations
NTIS Accession No.
Boulder City, NV: U.S. Department of the Interior, Bureau of Mines, RI 8560