Study On Preparation Of Doped Iron-based Oxygen Carrier By Metallurgical Dust

With the increasingly prominent environmental problems,the realization of the resource utilization of metallurgical solid waste is an important issue facing the industrial upgrading of the iron and steel metallurgical industry.As a metallurgical solid waste produced by the iron and steel smelting process,metallurgical dust contains a large amount of valuable elements such as iron and calcium,which has a high utilization value.The research on the development and utilization of such solid waste resources is of great significance for resource conservation and environmental protection,and is an urgent need for technical upgrading of metallurgical enterprises.In this paper,the acid-decomposition-coprecipitation method is used to transfer the valuable elements?Fe,Ca,Mg,Al,Mn,etc.?in the metallurgical dust to the acid solution,and the target precipitate is obtained by adjusting the pH value.After the roasting process,the doped iron-based oxygen carrier is obtained.By exploring the preparation method,the structure of the product and the oxygen carrying capacity,a new method for metallurgical dust material utilization is obtained.Firstly,metallurgical dust was used as raw material to explore its leaching rule and kinetics in hydrochloric acid,and the preparation parameters were optimized.On this basis,the practice of metallurgical dust to prepare doped iron-based oxygen carrier was explored.The microstructure and oxygen carrying properties of the product were investigated experimentally.Specific content and method:Using metallurgical dust and hydrochloric acid as reactants,the effects of temperature,liquid-solid ratio,acid concentration and leaching time on the leaching of valuable metals in metallurgical dust were investigated under single factor conditions.On the basis of this,the doped iron-based oxygen carrier?X-Fe₂O₃?precursor was prepared by hydrothermal precipitation method,and the doped iron-based oxygen carrier was prepared after sintering.The doped iron-based oxygen carrier was investigated experimentally.The body?X-Fe₂O₃?,pure Fe₂O₃ oxygen carrier,iron-based oxygen carrier?SiO₂-Fe₂O₃?with SiO₂ as the inert carrier,and iron-based oxygen carrier?Al₂O₃-Fe₂O₃?with Al₂O₃ as the inert carrier Reduction characteristics and cycle characteristics of oxygen.The optimum conditions for metallurgical dust leaching were as follows:hydrochloric acid concentration 5mol/L,liquid-solid ratio:15:1,temperature 80°C,and leaching rate of 91%when the leaching time was 1050s.The optimal experimental combination of the theoretical leaching of the precursors of the orthogonal test is:liquid-solid ratio 15:1,temperature 90?,sulfuric acid concentration 5 mol/L,time 1050s.The main order of leaching of main metal elements in Fe-Al-Ca-Si-Mg?FACSM?system in metallurgical dust is time>sulfuric acid concentration>liquid-solid ratio>temperature.In the 5mol/L hydrochloric acid system,the leaching temperature is in the range of 293k-353k.The leaching kinetics equation of the metallurgical dust is in accordance with the unreacted shrinkage nucleus model with the internal diffusion of the control link,and the activation energy is 37.97k J/mol.The shape of the doped iron-based oxygen carrier product prepared by metallurgical dust is mainly composed of rod-shaped,spherical and massive particles,and there is no obvious particulate matter on the surface.The temperature increases the size of the particles gradually decreases,but the uniformity of the particle distribution becomes worse.As the calcination temperature increases,the specific surface area and the average pore size show a tendency to increase first and then decrease,and the specific surface area decreases continuously and the average pore diameter gradually increases.Under the condition of H₂ reduction,the degree of reduction of pure Fe₂O₃ carrier is gradually increased in a certain temperature range,and in the higher temperature range,the degree of reduction is reduced due to the high temperature sintering of the oxygen carrier.The addition of alumina and silica and the multi-element micro-doping prepared from metallurgical dust greatly greatly increase the reaction rate and overall reduction and anti-sintering characteristics of the first stage of the reduction reaction.The research results show that the process route of preparing doped iron-based oxygen carrier by using metallurgical dust as raw material is feasible and the process is controllable.The method can realize the simultaneous materialization of iron in the metallurgical dust mud and various trace metal elements,and has positive significance for saving natural resources and protecting the environment.At the same time,the experimental results also provide a new idea for the high added value and refined utilization of other metallurgical secondary resources.