Research status and development of extraction process of zinc-bearing dust from ironmaking and steelmaking—a critical review

Almost 29.57–38.46 million tons of zinc-bearing dust were produced in Chinese iron and steel enterprises annually.The recovery of Zn and other metals in zinc-bearing dust from ironmaking and steelmaking could improve economic efficiency.However,zinc-bearing dust was classified as hazardous waste,and the volatile metals(like Zn,Na,Pb,etc.)in zinc-bearing dust limited the direct reusing in a blast furnace.Therefore,the formation process,fundamental characteristics,and current extraction process of Zn from zinc-bearing dust,associated with thermodynamics and kinetics of the pyrometallurgical process,hydrometallurgical process,and pyro-hydrometallurgical process,were analyzed.It is indicated that industrialized pyrometallurgical processes are undergoing high energy consumption and pollution such as rotary kiln and rotary hearth furnace process.The vacuum carbothermal reduction process can realize low carbon emission and no waste produced in the process.The hydrometallurgical leaching processes in strong acid,strong alkali,and ammonium solutions result in serious liquid pollution and equipment corrosion.The pyrometallurgical process involves complex kinetics and lacks kinetic research on semi-industrialization and industrialization.Water-soluble components in zinc-bearing dust can be removed by water leaching.The kinetics of the strong acid leaching is mainly controlled by the leaching kinetics of Fe_(2)O_(3) and ZnFe_(2)O_(4),while the alkali leaching and weak acid leaching are controlled by the kinetics of ZnO leaching.Zn in the zincbearing dust can be extracted by a low-temperature sodium roasting–weak acid leaching process that reduces equipment corrosion and environmental pollution.

Cellular structure of detonation utilized in propulsion system

How to confine a detonation in a combustor is a key issue of detonation applications in propulsion systems.Based on achieving schemes,detonations applied in the combustor,including pulse detonation wave(PDW),oblique detonation wave(ODW) and rotating detonation wave(RDW),are different from that described by the classic CJ theory in fine structures and its self-sustaining mechanisms.In this work,the cellular structures and flow fields of ODW and RDW were obtained numerically,and the fundamental characteristics and self-sustaining mechanisms of the detonations were analyzed and discussed.ODW front consists of three parts:the ZND-like front,the single-headed triple point front and the dual-headed triple point front.Cellular structures of RDW are heterogeneous,and the cell size near the outer wall is smaller than that near the inner wall.