Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Rare earth metal
Patent
1989-10-24
1993-01-19
Lewis, Michael
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Rare earth metal
423 211, 423 50, 423 55, 423140, C01F 1700, C22B 5900, C22B 4700, C22B 700
Patent
active
051805634
ABSTRACT:
A process for treating a sludge comprises digesting the waste material with a mixture of sulfuric acid and hydrogen peroxide to form an acidic digestion solution and a digestion residue. The digestion residue containing the major portion of tungsten and other refractory metals is reacted with NaOH to solubilize the major portion of tungsten values to a liquid concentrate that is separated from the insoluble solid that contains the major portion of the other refractory metals such as tantalum and niobium. The digestion solution containing the major portion of the transition and rare metals is treated with a base to selectively recover iron as a solid iron hydroxide precipitate which is separated from the resulting liquor. The liquor is then treated again with a base to selectively recover the other metals such as Sc, Cr, rare earths, but not Mn, as a solid metal hydroxide precipitate that is separated from the solution. The resulting solution containing the major portion of Mn is treated with a base to a pH of about 9.5 under an oxidative environment to recover manganese as a solid manganese hydroxide precipitate that is separated from the solution. The final waste effluent at a pH of 9.5 can be used for its alkali values and for diluting the concentrated acidic solution from the initial digestion of the waste materials.
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Lai Wen-Chao
Natansohn Samuel
Rourke William J.
Bos Steven
GTE Products Corporation
Lewis Michael
Ruoff Carl F.
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