| Blast furnace dust is one of the main solid wastes produced by iron and steel industry,which contains zinc and alkali metals such as potassium,sodium.When it is returned to sintering burdening,it will affect the air permeability of sintering material layer,affect the strength of material column,interfere with the distribution of gas flow and reduce the service life of blast furnace.At present,the harmful components of zinc-containing dust are mainly removed by fire reduction in rotary furnace and rotary kiln in China,but the applicability of high alkali metal blast furnace dust is poor,which limits the utilization of high alkali dust.This paper targeted removal of potassium,sodium,lead,zinc,chlorine and other harmful impurities in blast furnace dust,and the application of each recovery components through different processing technology.Reduce the environmental pressure of blast furnace smelting,and realize the green and comprehensive utilization of resources;It provides a new idea for the treatment and comprehensive utilization of the solid industrial wastes with complex composition,reduces the environmental cost of enterprises,and recycles the valuable components in the wastes to obtain profits.The high solubility of alkali metals was used to explore the process of removing alkali metals from Blast furnace dust by water leaching.After studying the influence of various factors on the leaching of alkali metals from blast furnace dust,the test results showed that the leaching was conducted at 40℃ for 45min with a liquid-solid ratio of 10:1.The potassium leaching rate reached 92.17%,and the potassium content in desalinated ash decreased to 1.08%.The sodium removal rate reached 81.90%,and the sodium content in the alkali ash decreased to 1.17%The dezincification experiment of blast furnace dust by carbothermal reduction was investigated based on the reduction characteristics of zinc.Thermodynamic analysis showed that direct reduction of zinc began at 950℃.After studying the influence of various factors on the dezincization by carbothermal reduction of blast furnace dust,the test results show that the content of dezincized dust can be reduced to 0.12%at 11 00℃ for 60min.At the same time,the mass loss of dezincized dust is the least,and the largest mass of Zinc hypoxide powder can be obtained.The analysis of carbon allocation shows that the optimum carbon allocation ratio is 1:10 when the mass ratio of carbon to dust is used for dezincting.After dealkalification and dezincization,the dust can be directly returned to sintering for utilization.Zinc hypoxide powder obtained by separation contains about 96.16%zinc oxide,which can be directly used as a secondary resource of zinc.Recrystallized KCl and coarse salt products were prepared by adsorption on activated carbon,pH adjustment of hydrochloric acid and evaporational recrystallization of the alkali solution.The results show that the recrystallized KCl contains about 93.6%KCl,the crude salt contains 38.39%KCl and 51.23%NaCl.The recrystallized product can be used as a secondary resource of potassium and sodium. |
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