| 摘要 |
<p>PURPOSE:To produce a compsn. for which iron making raw materials contg. Na2O and Al2O3 at low ratios and contg. Fe2O3 at a high ratio are usable by subjecting the residues after extraction of alumina by treating bauxite by a Bayer process to an acid treatment. CONSTITUTION:The bauxite is treated by an aq. caustic soda soln. and the alumina contained therein is separated and recovered as water-soluble sodium aluminate. Al(OH)3 is added as a precipitation seed to the soln. to precipitate the Al(OH)3 from the aq. sodium aluminate soln. This Al(OH)3 is used as the raw material for the Al2O3. The Al(OH)3 is precipitated from the aq. sodium aluminate soln. and the water-soluble silica is precipitated and separated from the aq. soln. recovered by filtration, thereby yielding the aq. sodium aluminate soln. of high purity. Fe2O3, Al2O3, Na2O, etc., remain in the remaining solid residues after the sepn. of the aq. sodium aluminate soln. and, therefore, a mineral acid is added thereto to elute the Al2O3 as an Al salt and to elute the Na2O as Na2Cl, Na2SO4, etc., by which the ratio of the Fe2O3 in the residues is increased. The raw material for iron making is thus produced by sintering, etc., together with limestone, coke, etc.</p> |
