| 摘要 |
Zinc and lead sulphide-contg. material is oxidatively roasted by forming the material into pellets of 2-15 mm. dia. with addn. of 2-20 (pref. 2-10) wt% zinc oxide powder and roasting in an oxygen-contg. gas in at least two stages, the first being at a lower temp. (pref. 850-950 deg.C) and the last being at a higher temp. (pref. 950-1050 deg.C). The process is used esp. for roasting mixed zinc sulphide and lead sulphide concentrates, or possible a lead sulphide core/zinc sulphide shell material (see GB2024792), to give an oxidic prod. suitable for charging to a blast furnace. The addn. of controlled amts. of zinc oxide, coupled with the use of carefully controlled oxidn. conditions, overcomes the problems of lead loss by volatilisation and incomplete sulphur elimination (i.e. lead loss is 25% or less and the residual sulphur content is less than 1%).
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