【摘要】 在锡尾矿选矿过程中产生大量低品位锡中矿,其砷、锡含量较高,回收利用价值大。研究基于此类锡中矿硫含量高的特点,创造性提出了一种自硫化焙烧方法,将该矿中砷、锡转化,分离和回收。包括还原焙烧和硫化焙烧两个阶段,在实施过程中无需额外添加硫化剂,可明显减少含硫污染气体的形成。在还原焙烧阶段,含砷物相FeAsS分解为FeS和As,As随后转化为As₄（g）和As₄S₄（g）挥发。通过烟气收尘工艺,可将砷高效富集回收。在焙烧温度973 K、焙烧时间90 min和CO分压30 vol.%条件下,还原焙烧渣中砷含量可降至0.72 wt.%。同时,生成的FeS可被矿样中共存态Fe₂O₃氧化成Fe_1-xS并进一步氧化成Fe₃O₄和SO₂（g）,SO₂（g）在气相扩散过程中被还原气氛中CO（g）还原并与矿样中独立态Fe₂O₃结合重新生成Fe_1-xS,稳定存在于焙烧渣中。在硫化焙烧阶段,Fe_1-xS可将SnO₂硫化成SnS（g）,实现锡的回收。在焙烧温度1223 K、焙烧时间90 min和CO分压60 vol.%条件下,锡在硫化焙烧渣中的含量可降至0.01 wt.%。此研究提供了一种从低品位锡中矿中分离回收砷和锡的有效方法。更多还原

【Abstract】 Massive amounts of low-grade tin middlings have been produced from tin tailings,in which arsenic and tin are worthy to be recycled.Owing to high sulfur content in these tin middlings,a novel self-sulfurization roasting was proposed to transform,separate and recover arsenic and tin in this research.There was no extra curing agent to be added,which decreased the formation of pollutant S-containing gas.The self-sulfurization process involved a two-stage roasting of reduction followed by sulfurization.First in reduction roasting,FeAsS decomposed to FeS and As and the As then transformed to As₄（g） and As₄S₄（g）,via which the arsenic was separated and recovered.The arsenic content in the first residue could be decreased to 0.72 wt.%.Accompanied with it,the FeS was firstly oxidized to Fe_1-xS and then to SO₂（g）by the coexisted Fe₂O₃,and finally reduced and combined with the independent Fe₂O to form Fe_1-xS.In the followed sulfurization roasting,the Fe_1-xS sulfurized SnO₂ to SnS（g）,due to which tin could be recovered and its content in the second residue decreased to 0.01 wt.%.This study provided an efficient method to separate and recover arsenic and tin from low-grade tin middlings.更多还原