Study On Key Technique Of Resource Utilization Of Sintering Dust

As a kind of important second resource, utilization of the sintering dust not only meet the political requirement of energy saving and discharge decreasing, but also bring the iron and steel makers a big economic benefit.In the paper, we have done benefication research on No.1,2,3 electrode dust made by 130m2 sintering machine. Through size analysis of these 3 dusts, we know that all these 3 dusts were fine particle dusts whose average size from 1 to 3 is 0.106mm, 0.102mm, 0.064mm respectively; and the chemical analysis shows that, the S, P content in this 3 dusts is relatively low which is easy to obtain high-quality Fe concentrate after benefication. As to the valuable elements like Fe, the content in this 3 dusts is 53.11%,49.32%,23.22%, the Pb content in these 3 dusts is 0.40%,1.39%,20.64%, all the information above suggests that recover Fe is the main target for No.1 and 2 dust, however as for No.3 dust, we need not only recover the Fe but also think of recover the Pb. XRD result of this 3 dusts tells us that, the Fe-bearing ores existed in this 3 dusts are mainly magnetite, hematite and so on. Besides No.3 dust has a lower content of Fe and non-magnetic ore takes up the most, so we have to use the roast and magnetic separation.The result of wet magnetic separation tells us that after low intensity magnetic separation and high intensity magnetic separation, we can get concentrate with 62.01% of TFe, and the recovery of Fe reach up to 92.57%; as to No.2 dust, under the optimum condition of benefication, concentrate with 57.47% of Fe grade as well as 92.38% of recovery will be obtained.The result of roasting-magnetic separation shows that the best conditions are: make the lignite be the reducer, 7% of the dosage, roasting temperature 850℃, roasting time 60min , grind granularity -0.038mm make up 73.25% of the total, maintain the magnetic field intensity at 150KA/m, we will obtain the fine with 51.12% of TFe, and recovers Fe as much as 84.25% of the total, besides the content of Pb in the fine is 1.75%, but 29.72% in the gangue, all the information above shows that the gangue of magnetic separation can be the material of recovering Pb.The flotation separation for recovering Pb to the magnetic separation gangue showed that under the optimum conditions we can get Pb concentrate with 34.14% for the grade and 76.27% for the recovery, yet Pb grade in the flotation gangue is still as much as 19.09%, that shows flotation actually is not the effective solution to separating Pb. Through the XRD analysis we learn that Pb has different existing forms in the gangue and PbO₂ as the most one, so we did acid leaching to recover Pb. The result showed that: dilute hydrochloric acid and NaCl of high concentration acted as the acid leaching media, raise the temperature as soon as possible to 80℃, keep the stirring rate at 500r/min, the liquid-solid ratio stay at 12:1, reacted about 60min, finally we got 96% of leaching rate .the magnetic separation gangue has around 14% of the Fe, which will accelerate in the leaching solution after recycling. In the paper we did research on influence caused by Fe ion in the liquor, the result tell that, Fe ion really has a certain impact on Pb leaching so after recycled for 3 times we need to add alkali to precipitate Fe and then filtrate the sedimentation, after which the supernatant can go back to the acid leaching system to make up new leaching solution.