Characterization of sinter flue dust to enhance alternative recycling and environmental impact at disposal

Abstract

Dust emission is one of the main environmental pollution impacts associated with steelmaking. In this sense, electrostatic precipitators (ESP) are regarded as the best available technique for treating this type of emission, thus generating two differentiated fractions: coarse and fine. Thorough chemical and structural characterization of both materials was carried out to recycle these byproducts in either the sintering process or other steps of pig iron production. Both types of dusts are crystalline heterogeneous materials mainly composed of sepiolite (Mg8Si12(OH)2•12H2O), hematite (Fe2O3) and calcite (CaCO3), the coarse fraction containing low amounts of Na (0.38  0.04%) and K (0.17  0.02%), which adversely affect blast furnace operation. Hence, the coarse fraction is suitable for recycling, whereas the fine one presents higher concentrations of these alkali elements. Besides, textural characterization revealed that dust particulates are essentially macroporous materials, with specific surface area values of 21.6 m 2 /g for the coarse fraction and 33.7 m 2 /g for dust fines. In order to ensure inoffensive dumpsites, the environmental behavior associated with dust particles accumulated in disposal areas was also evaluated by performing leaching studies simulating different rainfall scenarios. It was found that the specific leaching rates of Ca, Mg, K and S varied between 0.072  0.001 and 0.75  0.01 µgelement/(gdust•d), whereas slower leaching rates were obtained for heavy metals (Fe, Mn and Cu), the values ranging from (1.20  0.1)10-4 to (1.8  0.1)10-3 µgelement/(gdust•d). These low rates indicate that the leaching of sinter dusts compounds has minimal environmental impact.

The Physico-Chemical and Mineralogical Characterization of Mg-Rich Synthetic Gypsum Produced in a Rare Earth Refining Plant

“…It may also be indicative of the crystalline transition of anhydrous (anhydrite III-anhydrate II) form of the gypsum [47]. This can also be attributed to the partial dehydration of silicates [48,49]. The small endothermic peak which occurred between 658.64 • C (1.69%, weight loss), indicate the dehydration of iron and magnesium hydroxides [50].…”

Exploring the impact of dust storms on pastoralists’ livelihoods in West Iran: Social, economic, and environmental consequences

“…They damage crops, deplete soil fertility, and pose cardiovascular health risks (Mavhura, 2017). In general, it can be argued that the dust storm affects the livelihoods of pastoralists by contaminating the vegetation and water required for livestock and spreading livestock diseases (Alexander et al., 2018; Chen et al., 2018; Fraser, 2013; Masaguer et al., 2018). Therefore, it is a valid way to manage the dust storms, which increasingly requires initiatives to recognize farmers’ attitudes toward this incident (Taheri et al., 2020).…”

Stepwise extraction of zinc, indium and lead from secondary zinc oxide dusts Experimental study

“…At this stage, the specific processes for treating metallurgical dust solid waste include direct recovery and treatment process [6][7][8] , physical treatment process [9][10][11] , fire treatment process [12][13][14][15][16] and wet treatment process [17][18][19] . Among them, the pyrometallurgical treatment process is the most mature in industrial production and is the mainstream process of metallurgical dust recovery at this stage.…”