Separation and recovery of potassium chloride from sinter dust of a steel plant

Abstract

Many companies return sinter dust to sintering directly, resulting in circulation and accumulation of harmful elements, which will affect the collection efficiency, sinter quality, and the grade of blast furnace seriously. A new separation and recovery process of potassium from the dust was proposed, which included water leaching, solid liquid separation, purification, vacuum evaporation and cooling crystallisation. The results showed that the optimum conditions were as follows: the ratio of solid to liquid = 1:3, leaching time = 40 min, and leaching temperature = 80°C, leaching rate of potassium chloride reaches 99.99%. When solution weight loss is 97.5%, the evaporation of potassium chloride product reaches 97.96%, purity of potassium chloride in the crystal can be 75.15%. Based on experiment results, a mathematical model of leaching kinetic of potassium chloride including stirring temperature and leaching ratio is proposed.

Characterization and abatement of SOx, NOx and PCDD/Fs in iron ore sinter machine wind legs

“…Low-temperature pyrolysis (in the shortage of air) is a source of SOx, NOx emissions in the iron ore sintering process (Yang et al 2005;Zhang et al 2015;Zhou et al 2015a;Liu et al 2020). Combustion of solid fuel (in the abundance of air) is the source of CO 2 and high-temperature emissions such as KCl and PCDD/Fs (Ji et al 2017b;Yu et al 2019). The melting point of KCl is 771 o C and the boiling point 1437 o C. The formation of KCl is exothermic as given in Eq.…”

“…The chlorine present in the ESP deposit was essentially from KCl and PCDD/Fs. Based on the research of Shiu and Yu (Shiu et al 1988b;Yu et al 2019), 10 grams of ESP deposit was dissolved in 100 ml of acetone, hexane, and toluene. The ltrates were examined in QEMSCAN and EDAX and the results are shown in Fig.…”

“…The ner particles that fail to settle down in ESP (particulates) exit into the atmosphere through the stack and pose an environmental issue. The stack emission contains particulates of SOx, NOx, KCl, VOCs, PCDDs, and PCDFs (commonly referred to as PCDD/Fs) which pose healthrelated hazards (KAWAGUCHI et al 2002a, b;Yu et al 2019). The emission pro le of SOx, NOx, and VOCs in sinter pot apparatus was investigated by Juexiu Li (Li et al 2019).…”

Dissolution Kinetics of Chlorine from Iron Ore Sintering Dust

“…It has a production about 28 to 45 kg per ton of steel, as evaluated by previous data [4], meanwhile it is also considered as a kind of hazardous waste because of its complicated components such as chlorides, heavy metals and dangerous organics [5]. As one of the main solid wastes of iron and steel plants, the treatment of sintering dust is still a headache of a steel plant [6,7]. Recycling this waste materials back into the iron ore sintering process is a general disposal approach worldwide.…”

“…However, most of the previous studies only removed the chlorine as a side-effect of extracting potassium from iron ore sintering dust in the form of KCl [7], while the investigation of chlorine removal was neglected. The chlorine mainly exists in the form of chlorides such as KCl, NaCl, ZnCl , PbOHCl, etc.…”