Application Of Flue Ash Of Arc Furnace In Exothermic Insulation Riser Sleeve

The arc furnace flue ash is the main solid waste in the steelmaking electric of arc furnace,mainly containing iron,zinc,calcium,cadmium,manganese and chromium oxides,making arc furnace flue ash become a solid hazardous waste.In this paper,the alkali leaching zinc and zinc extraction test of arc furnace flue ash was carried out,and the crude zinc was obtained.The research focus is on the physical non-toxic treatment test of arc furnace flue ash,whcih can make it become general solid waste;the experimental study on the preparation of exothermic insulation riser sleeve by using arc furnace flue ash as oxidant can obtain the exothermic insulation riser sleeve with good performance.Firstly,the sodium hydroxide leaching test was carried out on the arc furnace flue ash.Through single factor and orthogonal experiments,the optimum conditions were determined as follows:sodium hydroxide concentration of 10%,liquid-solid ratio of 5:1,reaction temperature of 65℃,reaction time of 2 h.At this time,the leaching rate of zinc was 92%.At the same time,1mol/L sulfuric acid was used to adjust the leaching solution Ph,and 20%sodium carbonate was used to recover the zinc in the leaching solution to obtain Zn CO₃,with a recovery rate of 90%.Secondly,the experimental study on the physical non-toxic treatment of the flue ash of the arc furnace was carried out by using the general solid waste arc gas explosion ash,steel cord skin and fine casting dust.Three kinds of solid waste were mixed with arc furnace flue ash at a ratio of 1:1,2:1,3:1,4:1,and the mixture was leached by sulfuric acid nitric acid method.The toxicity of solid waste leaching was deteccted by ICP,and the concentration limit of dangerous components in the leaching solution could be lower than the national limit.Therefore,the arc furnace flue ash can be generally used as solid waste for resource utilization.Thirdly,the experimental study on the preparation of exothermic insulation riser sleeve with arc furnace flue ash as oxidant.It is determined that the new exothermic insulation riser sleeve takes aluminum powder,silicon powder and aluminum chips as the main heating materials,takes arc furnace flue ash,manganese dioxide and sodium nitrate as the oxygen supply materials,takes sodium fluoroaluminate as the cosolvent,takes hollow floating beads as the aggregate insulation material,takes liquid phenolic resin as the binder,and adds alcohol and other auxiliary materials to carry out the research and development test of the new exothermic insulation riser sleeve.During the experiment,the addition of heating materials and aggregate hollow floating was tested.It was found that the heating material was increased from 40%to 48%,and the hollow cenosphere was reduced from 32%to 24%.The maximum combustion temperature of the prepared exothermic insulation riser sleeve was 1472℃,the compressive strength was5.921 MPa,and the holding time was 228 s.The maximum combustion temperature increased by 4.3%,the holding time increased by 9.6%,and the compressive strength was not much different.The appropriate proportiont of each parameter was determined by single factor test,namely:heating material（aluminum powder 15%,silicon powder 26%,aluminum scrap7%）,oxygen supply material（arc furnace flue ash 9%,manganese dioxide 7%,sodium nitrate 8%）,combustion-supporting material（sodium fluoroaluminate 4%）,adhesive（liquid phenolic resin 14%）.At this time,the maximum combustion temperature of the prepared exothermic insulation riser sleeve is 1471℃,the compressive strength is 6.543 MPa,the permeability is 197.5,the ignition time is 40 s,the holding time is 223 s,and the secondary combustion time is 38 s.Fourthly,the experimental study on the addition of 9%arc furnace flue ash in the exothermic preservation riser sleeve was replaced by the non-toxic mixed solid waste of arc furnace flue ash.It is concluded that when the arc furnace flue ash is mixed with the arc gas ash by 1:1,the arc furnace flue ash is mixed with the steel cord skin by 3:1,and the arc furnace flue ash is mixed with the fine casting dust by 1:1 to replace the arc furnace flue ash respectively,the performance of the prepared exothermic insulation riser sleeve is the best.