Study On Recovery Of Iron And Carbon Elements And Removal Of Harmful Elements From Dust Of Iron Works

The dust of ironworks is a secondary resource of metallurgical solid waste,but it is difficult to utilize it efficiently at present.Iron carbide is a kind of high quality steel making raw material which can replace scrap with high added value and has broad application prospect.In this paper,high quality steel making raw materials such as iron carbide and high grade carbon ore can be prepared by reducing chlorination,carburizing,magnetic separation and acid leaching using blast furnace dust and sintered dust produced in the process of iron making.In addition,the mechanism of the removal of lead and zinc,the preparation of iron carbide concentrate and carbon ore was further studied.The research results of this paper can provide a new way and theoretical basis for the comprehensive utilization of dust in ironworks.In this paper,the process of producing iron carbide concentrate,high grade carbon ore and removal of harmful elements lead and zinc from dust in iron works is studied systematically,and the process parameters are optimized.The results showed that the reduction chlorination temperature of 1000℃,reduction chlorination time of 15 min,sodium carbonate additive content of 9%,CO-CO2-H2 as carburizing gas,carburizing temperature of 700℃,carburizing time of 120 min,grinding size less than 0.045mm accounted for 70.08%.Under the magnetic field intensity of 130 mT,high grade iron carbide with iron grade,combined carbon content and iron recovery of 86.95%,6.18%and 92.48%can be prepared,and the removal rates of lead and zinc are 79.94%and 74.79%,respectively.Under the conditions of acetic acid leaching concentration of 4 mol/L,acid leaching temperature of 80℃,acid leaching time of 80 min,sulfuric acid leaching concentration of 0.3 mol/L,acid leaching temperature of 80℃,acid leaching time of 70 min,the mass fraction of carbon 77.25%carbon ore can be obtained.The mechanism of reducing chlorination,carburizing and acid leaching of dust in iron works was studied.The results show that:1.In the process of reduction chlorination,the carbon in blast furnace dust dust promotes the reduction of iron oxide,strengthens the reduction chlorination reaction,and promotes the growth of iron mineral particles.The sodium carbonate additive accelerates the combustion reaction of carbon and further increases the reduction chlorination rate.In addition,the additives promote the lattice distortion of iron minerals and increase the particle size of iron minerals.2.In the process of carburizing,the sodium carbonate additive promotes the growth of iron carbide particles.Improve the distribution relationship between iron minerals and gangue.High temperature can promote the aggregation and growth of iron particles and gangue modification,but high temperature is not conducive to carburizing.When the carburizing time is short,the reduction reaction mainly occurs,and the content of iron carbide is low,and the degree of gangue sodium modification is low.Prolonging carburizing reaction time is beneficial to carburizing reaction and sodium reaction.3.In the process of acetic acid leaching,calcium salt in magnetic separation tailings can be effectively removed.After sulfuric acid leaching,the remaining sodium-bearing gangue can be further removed,and the grade of carbon ore can be significantly improved.