| 摘要 |
<p>A process for thermally decomposing salts which contain mainly iron sulfate, in a fluidized bed circulating in a vertical shaft, wherein a major part of the resulting metal oxide is discharged together with the gas from a top part of the shaft and is separated from the gas in a recycling cyclone and is recycled at least in part to the fluidized bed, the exhaust gas from the fluidized bed is contacted with feed salt containing mainly iron sulfate, the fluidized state is maintained by oxygen-containing fluidizing gas, which optionally has been preheated, and by oxygencontaining secondary gas, which optionally has been preheated and which has been fed above the inlet for the fluidizing gas, and fuel is fed into a zone between the inlets for the fluidizing gas and secondary gas. The process of the invention is characterized in that the salt which contains at least one mole of water of crystallization and mainly contains iron sulfate is contacted in a single suspension-type exchanger with exhaust gases formed by reaction of the oxygen-containing gases in the fluidized bed, the fluidizing gas and at least a partial stream of the secondary gas stream are heated by an indirect heat exchange in a fuel-heated heat exchanger, and the quantity of oxygen introduced via the fluidizing gas and the secondary gas, is controlled in dependence on the quantity of fuel in order to receive an exhaust gas from the suspension-type exchanger with a free oxygen content of 1-6% by volume and a temperature of 300-450.degree.C. The process has proved to be satisfactory for the decomposition of salts which contain iron sulfate and especially when such salts contain also adherent sulfurin acid.</p> |
