| 摘要 |
Residual Bayer alumina process "Red Muds" are heated at 140-190 DEG C. with caustic soda lye containing a quantity of Na2O 25-30 per cent. by weight in excess of the amount necessary to form Na2O.Fe2O3 and Na2O.Al2O3 ground and lixiviated with hot water to produce hydrated iron oxide for desulphurizing gases. The material is preferably agglomerated with peat into shaped masses and dried in the open or in a kiln. The agglomerates may be freed from sulphur with solvents even above the melting point of sulphur without disaggregation. The lixiviation liquor containing dissolved alumina and vanadic acid may be recycled to a point at the Bayer cycle ahead at the final concentration of decomposed aluminate liquors according to their Na2O content. Specifications 332,259, [Class 1 (iii)] and 429,321 are referred to. |
