Iron & steel production sees the most pollutant emissions in the sintering of iron ore, a process in which iron-making materials that cannot be directly put in a furnace (including iron powder, rich ore fines, roll scale, and blast-furnace dust), mixed with a certain amount of fuel (including coke powder and anthracite) and flux (including limestone and dolomite), are heated up to XX-XX℃ to make the powder sintered to blocks, which, after undergoing a range of processes including crushing, screening, and cooling, will become finished sinter available for blast furnace iron-making.^[1] A great deal of flue gas is generated during sintering, which is responsible for roughly XX%­–XX% of total gaseous pollutant emissions in iron & steel production. ^[2-5]
 

烧结过程需要消耗大量的燃料和矿石，燃料和矿石中除含一定量的硫分外，还含有一定量的汞、铅、铬、镉等重金属。烧结机头排放的高温烟气除二氧化硫、氮氧化物及颗粒物等常规污染物外，其汞、铅、铬、镉等重金属的排放问题也广受关注^[6-7]。据报道，铁矿石中的汞含量一般为XX-XXmg/kg^[8]。相关研究表明，每生产1吨粗钢将排放40mg左右的汞，其中XX%以上是以气态零价态汞的形式随烧结烟气排入大气，其余是气态二价汞及颗粒汞^[9-11]。

Sintering requires large quantities of fuel and ores, which contain certain amounts of heavy metals such as mercury (Hg), plumbum (Pb), chromium (Cr), and cadmium (Cd), in addition to a certain amount of sulfur content. Apart from conventional pollutants like sulfur dioxide (SO₂), nitric oxides (NO_X), and particulate matters — among the high-temperature flue gases emitted by the head of sintering machines — heavy metal emissions such as mercury, plumbum, chromium, and cadmium are sparking increasing attention^[6-7]. Reportedly, the mercury content in iron ore is generally XX-XXmg/kg^[8]. As shown by relevant studies, each tonne of produced crude steel means around 40mg of mercury emissions, above 80% of which go into the air in the form of gaseous zero-valent mercury along with sintering flue gas, with the remaining XX% existing in the form of gaseous divalent mercury and mercury particulates^[9-11].
 

污染治理设施对重金属污染物有一定的去除效果，国内外对烧结机烟气汞排放有相关研究^[12-17]，而对铅、铬、镉等重金属污染物研究较少，重金属污染物具有难生物降解，危害程度大、周期长等特点。因此研究烧结机Hg、Pb、Cd和Cr 等重金属污染物排放特征，对控制大气重金属污染，降低生态环境和人体健康危害有重要的现实意义。小型烧结机分布较广，大多数未完成超低排放改造，研究污染治理设施对重金属污染物的去除效果，可为超低排放控制措施的选择提供依据。

    As pollution control facilities can help to remove heavy metal pollutants to some extent, studies have been carried out in both China and elsewhere with respect to mercury emissions from flue gas of sintering machines. However, there have been few studies out there regarding such heavy metal pollutants as plumbum, chromium, and cadmium, all of which feature difficulties in biodegradation, great harm, and prolonged cycles, among others. As such, delving into the characteristics of heavy metal pollutants (Hg, Pb, Cd, and Cr) emitted by sintering machines can be of great realistic significance to control heavy metal pollution in the air, and thus to minimize harms to the ecological environment and human health. Small-sized sintering machines are widely distributed and many of them have yet to complete upgrading towards ultra-low emissions (ULE). In light of this, this study into the efficiency of pollution control facilities on removing heavy metal pollutants may provide a basis for selecting ULE control measures.