Return fines of sinter (return fines) are used to prepare cold‐bonded briquettes (CBBs). The reduction disintegration index (RDI) of RDI+3.15 and compressive strength after RDI experiment of CBB are higher than that of the sinter. For microscopic morphologies after RDI experiment, cracks initiate in the area of the return fines but do not propagate through the whole matrix of CBB. The reduction index (RI) of CBB is lower than that of the sinter; conversely, the compressive strength of CBB after RI experiment is higher than that of the sinter. For phase composition after RI experiment, there are phases of metallic iron, wüstite, and silicate in the periphery part, whereas there are calcium ferrite, wüstite, and silicate in the core part. The reduction behavior of CBB can be improved by decreasing the volume of CBB and adding coke in the CBB. The return fines are bonded by the compound binder in two ways: forming a mutually interlaced reticular structure and a dense and acicular solid connecting bridge. For the phase change of the compound binder with temperature, the total content of bredigite is above 63% at 300 to 1100 °C; moreover, the phases of melilite, Ca2(Al, Fe)2O5, and Ca(Al, Fe)2O4 appear respectively at different temperatures as new bonding phases.
An industrial furnace, such as a blast furnace, molten salt furnace and a basic oxygen furnace, is a popular reactor, where the distribution of liquid, flow pattern of the fluid and the velocity of the fluid determine the energy distribution and chemical reaction in the reactor. Taking a furnace as the research object, this paper studies the effects of different inlet velocities, liquid densities and viscosity on bubble and velocity distribution. A three-dimensional mathematical model of the furnace is set up by a numerical simulation, and the volume-of-fluid (VOF) method is used to study the behavior of bubbles. The accuracy of the simulation parameters selected in the simulation calculation is verified by comparing the simulation with the experimental results. The findings show that an excessive or too small an inlet velocity will lead to an uneven distribution of chlorine in the furnace, therefore, an inlet velocity of about 30 m/s is more appropriate. In addition, changing the liquid density has little effect on the bubble and velocity distribution while choosing the appropriate liquid viscosity can ensure the proper gas holdup and fluidity of chlorine in the furnace.
Brown corundum fly ash (BCFA), which is the collected ash in brown corundum production, has received lots of environmental concerns due to its ultra-fine particle size and complex composition. Aiming to recycle the major elements including K, Al and Si from BCFA environmentally, this work proposed a simple and non-pollution process to utilize BCFA by water leaching, size screening and solution evaporation. The influences of water leaching conditions including leaching temperature, time and liquid-to-solid ratio was considered to optimize the K2SO4 recovery efficiency. Results show that the potassium sulfate content of the product is 75.7% after water leaching at 60 °C for 15 min with the liquid–solid ratio of 20:1. The wet screening and size separation with a 1 μm sieve can separate and enrich aluminum and silicon significantly. The aluminum-rich product is composed of 54.65% of alumina and 11.04% silica, with the alumina and silica ratio (A/S) of 4.95. The silicon-rich product with a particle size of less than 1 μm has a silica content of 57.57% can be used as high-value micro-sphere silica. The research results revealed in this work offers a potential and environmentally industrial treatment technique for the BCFA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.