Study On Preparation And Characteristics Of Doped Nano-iron Oxide From Metallurgical Iron-containing Dust

In recent years,my country's national economy has developed rapidly and people's living standards have continued to improve.The reason is that the iron and steel industry has played a mainstay role.However,due to the imperfect steel smelting technology in our country,a large amount of metallurgical solid waste will be generated during the process of producing steel.If it is not treated and utilized,it will cause waste of resources and environmental pollution.As one of the main solid wastes,metallurgical dust contain valuable elements such as iron,aluminum,zinc,copper,etc.,and have high utilization value.This subject uses the process of acid leaching-precipitation-roasting to transfer the valuable element Fe in the metallurgical dust to the acid leaching solution.The target precipitate is obtained by adding alkali to the leaching solution to adjust the p H value,and then the precipitate is roasted to obtain doped nano-iron oxide.By exploring the best preparation process,product particle size and adsorption performance,a new way to use metallurgical dust with high added value is obtained.First,use metallurgical dust as raw materials to explore the total leaching law of iron and elements in hydrochloric acid.And the best process parameters are obtained.On this basis,the preparation of doped nano-iron oxide is studied by precipitation roasting method,and the particle size and adsorption performance of the product are analyzed.The specific operation is as follows:explore the influence of hydrochloric acid concentration,acid leaching temperature,acid leaching time,and liquid-solid ratio on the total leaching rate of iron and elements in metallurgical dust in hydrochloric acid through the single control variable method.On this basis,the doped nano-iron oxide is prepared by precipitation method and roasting,and the influence of reaction temperature,ammonia concentration,roasting temperature and roasting time on the particle size of doped nano-iron oxide is explored,and the particle size is measured with a laser particle size analyzer and a transmission electron microscope.Finally,the prepared doped nano-iron oxide is used to adsorb the rare earth ions Nd³⁺and La³⁺to explore the adsorption performance.The main conclusions are as follows:The optimal leaching conditions of metallurgical dust obtained in the experiment are:hydrochloric acid concentration 7mol/L,acid leaching temperature 50?,acid leaching time 30min,liquid-solid ratio 10:1,and the leaching rate of iron in metallurgical dust is about 80%,the total leaching rate of elements is about 90%.On this basis,the optimal conditions for preparing doped nano-iron oxide are as follows:reaction temperature 70?,ammonia concentration 3mol/L,calcination temperature200?,calcination time 2h,the particle size of the obtained doped nano-iron oxide is about 277.25nm measured with a laser particle size analyzer.,which is the same as the best process conditions obtained by measuring the particle size of doped nano-iron oxide by transmission electron microscopy.Under this condition,the particle size of the product measured by transmission electron microscope is about 50nm.The calcining temperature is in the range of 100-600?.The specific surface area and porosity of the prepared doped nano-iron oxide increase first and then decrease with the increase of the calcination temperature.When the calcination temperature is200?,the specific surface area and porosity reach maximum.The doped nano-iron oxide prepared under the optimal conditions is used to desorb the rare earth ions Nd³⁺and La³⁺,and the influence of dosage,adsorption temperature and adsorption time on the adsorption performance of the doped nano-iron oxide is explored.The optimal adsorption conditions are:dosage is 50mg,adsorption temperature is 70?,and adsorption time is 3h.At this time,the adsorption rates of doped nano-iron oxide for Nd³⁺and La³⁺are 50.74%and 51.84%,respectively.