Due to the increasing use of scrap galvanized steel in converter process, the content of zinc in converter dust is rising gradually as a result of zinc enrichment and accumulation, which will cause problems to dust recycling from long-term production stability and safety. The aim of this study was to reveal the chemical, physical, mineralogical and morphological characteristics of zinc-containing converter dust. The study shows that the concentration of Fe, Ca, Zn is 52.43~54.25%, 5.97~6.09%, 3.60~3.73% respectively. The phases such as Fe3O4, Fe2O3, FeO, ZnFe2O4, ZnO and C were detected through XRD analysis. Granulometric analysis indicated that, the particle size distribution is very concentrated and almost 80% of particles are finer than 1μm. Further researches on integrated utilization process are necessary in order to develop effective method to recycle zinc-containing converter dust.

Hydrothermal carbonization (HTC) technology was used to carbonize and improve biomass raw material to obtain hydrochar. The effects of HTC temperature and holding time on the yield, composition, structure, combustion behavior, and safety of hydrochar were studied systematically. In addition, the results show that with the increase in HTC temperature and the prolongation of holding time, the yield of hydrochar gradually reduces, the fixed carbon content of hydrochar increases, the volatile content decreases, and a large number of ash and alkali metals enter the liquid phase and are removed. Further, the analysis of the combustion properties and the structure of hydrochar can be observed in that, as the HTC process promotes the occurrence of polymerization reactions, the specific surface area gradually reduces, the degree of carbon ordering increases, and the combustion curve moves toward the high-temperature zone and gradually approaches bituminous coal. Since biomass hydrochar has the characteristic of being carbon neutral, blast furnace injection hydrochar can reduce CO2 emissions, and every 1 kg/tHM of biomass hydrochar can reduce CO2 emissions by 1.95 kg/tHM.

No abstract

No abstract

No abstract