| 摘要 |
<p>1,271,733. Sulphur dioxide; metal oxides. ELCOR CHEMICAL CORP. 22 July, 1969 [22 July, 1968], No. 36863/69. Headings C1A and C1N. A metal sulphate is converted to sulphur dioxide and the metal oxide, by first subjecting the sulphate to reducing conditions to produce sulphur dioxide, the metal oxide and the metal sulphide, and then subjecting the mixture of solids thus obtained to oxidizing conditions to convert the metal sulphide to metal oxide, metal sulphate and sulphur dioxide. Preferably the reactions occur in the range 2000-2500‹ F., and the reducing gas comprises a hydrogen/carbon monoxide mixture, while the oxidizing gas may be e.g. air. The process is especially suitable for alkaline earth metal sulphates but those of aluminium, cerium, chromium, cobalt, potassium, lithium, sodium, nickel, lead, thorium, titanium, vanadium and zinc may also be treated. A series of reduction-oxidation cycles may be invoked so that substantially all of the sulphur content of the sulphate is driven off as sulphur dioxide (which may then e.g. be converted to sulphuric acid). Suitable apparatus for the execution of the process is described. The process is particularly applicable to processing of CaSO 4 in lumps of 0À25-1À50 inches in maximum dimension.</p> |
