A new approach for recycling arsenic and tin from low-grade tin middlings using a self-sulfurization roasting  

自硫化焙烧法从低品位锡中矿高效回收砷和锡

作　　者：LI Lei XU Zhi-peng HE Jun-li XIAO Yang SUN Yi-xuan LEI Yun ZHOU Juan 李磊;徐志鹏;何俊力;肖阳;孙宜轩;雷云;周娟(College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China;Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,China;Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China [2]Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,China [3]Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China

出　　处：《Journal of Central South University》2024年第9期3050-3067,共18页中南大学学报（英文版）

基　　金：Project(52174384)supported by the National Natural Science Foundation of China;Project(LZB2021003)supported by Fundamental Research Funds for the Central Universities,China。

摘　　要：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 As_(4)(g)and As_(4)S_(4)(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−x)S and then to SO_(2)(g)by the coexisted Fe_(2)O_(3),and finally reduced and combined with the independent Fe_(2)O_(3)to form Fe_(1−x)S.In the followed sulfurization roasting,the Fe_(1−x)S sulfurized SnO_(2)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.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As_(4)(g)和As_(4)S_(4)(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Fe_(2)O_(3)氧化成Fe_(1−x)S并进一步氧化成Fe3O_(4)和SO_(2)(g),SO_(2)(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Fe_(2)O_(3)结合重新生成Fe_(1−x)S,稳定存在于焙烧渣中。在硫化焙烧阶段,Fe_(1−x)S可将SnO_(2)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。

关 键 词：low-grade tin middlings continuous sulfur transformation self-sulfurization separation of arsenic and tin RECYCLING 

分 类 号：TF843[冶金工程—有色金属冶金] TF814