| 摘要 |
In a continuous process for roasting arsenopyrites ores the ore is preheated in a separate stage, by direct heat exchange with a portion of the sulphur dioxide gases from the roasting stage, to a temperature e.g. 500-550 DEG C. such that arsenic compounds e.g. arsenic sulphide, are distilled off, but labile sulphur is not, the preheated ore is passed to the roasting stage and the remainder of the sulphur dioxide gases are recovered as arsenic-free gas. The preheating and roasting stages are fluidized, and are both in the same vessel, in the apparatus described. The arsenic-free gas is also passed in indirect heat exchange with the ore in the preheating stage and some may be recycled to the roasting stage. The portion of the sulphur dioxide gases is cooled to condensate the arsenic compounds. |
