| 摘要 |
<p>1,242,938. Purifying roasted iron pyrites. MONTECATINI EDISON S.p.A. 7 July, 1969 [8 July, 1968], No. 34115/69. Heading C1A. Iron pyrites cinders (haematite) is freed from arsenic and non-ferrous metals by reducing the cinders, using air and a carbonaceous fuel, at 850-950‹ C. with a contact time of 30-90 minutes to effect a 10-50% reduction of haematite to magnetite; chlorinating the partially reduced cinders in a fluidized bed at 650-950‹ C. with a contact time of 30-120 minutes in an oxidizing atmosphere such that the oxygen content of the exhaust gases is at least 3% by volume; and then leaching the chlorinated product with a 0À2-2% by wt. aqueous solution of a mineral acid, e.g. HC1 and/or H 2 SO 4 using a liquid/solid weight ratio of at least 2 : 1 and a contact time of 15-30 minutes. The fluidized bed chlorination may be effected in 2 or more stages. If the iron content of the chlorinated cinders is low, they may be subjected to a magnetizing reduction and magnetic concentration before the acid leach. The purified cinders may be pelleted.</p> |
