Dust Treatment Research Articles

Thermodynamic Study of the Sustainable Hydrometallurgical Treatment of Copper Converter Flue Dust Based on Pb, Zn, and Sn Oxides

Thermodynamic Study of the Sustainable Hydrometallurgical Treatment of Copper Converter Flue Dust Based on Pb, Zn, and Sn Oxides

Physiological changes in shrub species due to different sources of dust pollution in an urban environment.

Plants effectively filter ambient air by adsorbing particulate matter. The correct selection of landscape plants can exert greater dust retention benefits in different polluted areas. However, few studies have focused on the dust retention ability and related physiological responses of plants under continuous dust pollution from different dust sources. Here, we assessed the particle retention dynamics and plant physiology (chlorophyll content, soluble protein content, soluble sugar content, and peroxidase activity) of six shrubs (Berberis thunbergii var. atropurpurea, Ligustrum vicaryi, Rosa multiflora, Sorbaria sorbifolia, Swida alba, and Syzyga oblata) under continuous dust pollution from different dust sources (industrial sources: area below the direction of the coal-fired thermal power plant in Chengyang District, Qingdao, China; traffic sources: both sides of the road in each direction at the intersection of Great Wall Road and Zhengyang Road, Chengyang District, Qingdao, China; clean sources: Qingdao Agricultural University Campus, Qingdao Olympic Sculpture Park). The results showed that R. multiflora had the highest dust retention per unit leaf area of 3.27 ± 0.018g·m-2 and 2.886 ± 0.02g·m-2 in the experimental treatments of fuel source dust and clean source dust, respectively. The chlorophyll content of the tested shrubs significantly decreased due to the influence of dust treatment time, the range of cellular osmoregulatory substances (soluble sugars, soluble proteins, proline) tended to first increase and then decrease, and the antioxidant enzyme activities (superoxide dismutase, peroxidase) tended to increase and then decrease after continuous dust treatment. The greatest physiological changes were observed in plants within the industrial dust treatment area. The peroxidase activity and chlorophyll could be used as sensitive indicators of dust pollution in plants. R. multiflora showed better resistance to dust and had a greater dust retention capacity than other shrubs, making it more suitable for planting as a greening tree in industrial and traffic-polluted areas. S. alba and S. sorbifolia are sensitive to dust pollution, so they can be used as sensitive tree species to indicate atmospheric dust pollution. Our results may help design a feasible approach for urban shrub greening.

Evaluation of steel metallurgical dust management: combining treatment methods and resource attributes

The escalating challenges of resource scarcity and environmental pressures have drawn significant attention to heavy metal-containing dust generated during steel production. While previous research on heavy metals in steel manufacturing has primarily focused on emission inventories, health and ecological risks, and recycling technologies, the assessment of steel metallurgical dust management has been largely overlooked. To address this research gap, this study employed statistical entropy analysis to evaluate the effectiveness of dust treatment in the steel production process, aiming to identify potential issues in dust management. Furthermore, an evaluation framework was established to systematically assess the resource attributes of steel metallurgical dust, thereby supporting evidence-based decision-making in dust management. Results indicate that Cd, Pb, As, Zn, Cr, and Hg tend to accumulate in dust during steel production. Given its high resource attribute, converter dust should be prioritized for recovery. Further analysis suggests that the rotary kiln process plays a transitional role in dust recovery. This study provides a scientific foundation for dust management in the steel industry and offers guidance for the sustainable development of dust utilization.

TREATMENT OF COPPER FLUE DUST FROM FLASH FURNACE WASTE HEAT BOILER FOR IMPURITIES CONTROL

During the pyrometallurgical processing of copper sulphide raw materials, part of the charge leaves the furnace space together with the exhaust gases in the form of dust entrainment. Volatile components also pass into the dust-gas flow, due to which it is enriched with impurities, some of which are harmful to the technological process. The formed dust-gas flow passes through dust collection equipment, where the main part of it is captured. Most often, the captured dust is recirculated, which leads to a decrease in the productivity of the furnace unit and a gradual increase in the content of impurities in the condensed products of the smelting. To overcome these disadvantages, it is necessary to take part or all the recirculating dust out of the melting cycle and process it independently to extract the valuable metals and dispose of the harmful substances. In metallurgical practice, industrial application for the processing of recirculating dust entrainment has mainly been accomplished by hydrometallurgical methods based on treating the flue dust in aqueous solutions of acid or alkaline reagents. In the present research work, laboratory results on hydrometallurgical leaching of flue dust from a flash furnace waste heat boiler (FF-WHB) are presented. The effect of the main technological parameters affecting the degrees of recovery of the main metals in solution was studied. Based on the experimental results, the optimal conditionsfor hydrometallurgical treatment of the FF-WHB flue dust were determined. By treating the dust under optimal conditions, the main tasks of the research are achieved - removal of impurities harmful to the technological process and reduction of the amount of flue dust processed in the flash furnace.

Rossby wave instability and substructure formation in 3D non-ideal MHD wind-launching discs

ABSTRACT Rings and gaps are routinely observed in the dust continuum emission of protoplanetary discs (PPDs). How they form and evolve remains debated. Previous studies have demonstrated the possibility of spontaneous gas rings and gaps formation in wind-launching discs. Here, we show that such gas substructures are unstable to the Rossby wave instability (RWI) through numerical simulations. Specifically, shorter wavelength azimuthal modes develop earlier, and longer wavelength ones dominate later, forming elongated (arc-like) anticyclonic vortices in the rings and (strongly magnetized) cyclonic vortices in the gaps that persist until the end of the simulation. Highly elongated vortices with aspect ratios of 10 or more are found to decay with time in our non-ideal magnetohydrodynamic (MHD) simulation, in contrast with the hydro case. This difference could be caused by magnetically induced motions, particularly strong meridional circulations with large values of the azimuthal component of the vorticity, which may be incompatible with the columnar structure preferred by vortices. The cyclonic and anticyclonic RWI vortices saturate at moderate levels, modifying but not destroying the rings and gaps in the radial gas distribution of the disc. In particular, they do not shut-off the poloidal magnetic flux accumulation in low-density regions and the characteristic meridional flow patterns that are crucial to the ring and gap formation in wind-launching discs. Nevertheless, the RWI and their associated vortices open up the possibility of producing non-axisymmetric dust features observed in a small fraction of PPDs through non-ideal MHD, although detailed dust treatment is needed to explore this possibility.

Efficacy of steam and diatomaceous earth dust against the tropical bed bug Cimex hemipterus (F.) under laboratory and field conditions.

Over the past two decades, bed bugs (Cimex spp.) have resurged as common urban pests around the world. The search for efficient and safe control measures has become a key interest among researchers, manufacturers, and pest control professionals. In this study, we evaluated and compared the efficacy of steam, diatomaceous earth (DE) dust, and a combination of both against tropical bed bugs (Cimex hemipterus (F.)) under laboratory and field conditions. In the laboratory study, the mortality of bed bugs after 2 days of exposure to DE dust was 100%. When bed bugs stayed on the surface of an object or in cracks, a brief steam treatment (1 s) caused 100% mortality. However, when bed bugs were hidden under a fabric cover, steam application for 10 s only caused 89 ± 6% mortality. Bed bugs that survived steam treatment exhibited reduced feeding activity. In a 14-week long study, there was no significant difference in the reduction rate of bed bugs between steam treatment and DE dust treatment. A 37-week long control study showed that steam and steam plus DE dust treatments eliminated 97-100% of the infestations. Applying steam and DE dust are effective strategies for eliminating natural tropical bed bug infestations. Continuous follow-up monitoring and treatment until no bed bugs are found are crucial in completely eliminating the infestation of tropical bed bugs. © 2024 Society of Chemical Industry.

Expanding the simulation of East Asian super dust storms: physical transport mechanisms impacting the western Pacific

Abstract. Dust models are widely applied over the East Asian region for the simulation of dust emission, transport, and deposition. However, due to the uncertainties in estimates of dust transport, these methods still lack the necessary precision to capture the complexity of transboundary dust events. This study demonstrates an improvement in the Community Multiscale Air Quality (CMAQ) model dust treatment during long-range transport of dust from northwestern China to the South China Sea (SCS). To accomplish this, we considered a super dust storm (SDS) event in March 2010 and evaluated the dust scheme by including adjustments to the recent calibration (Dust_Refined_1) and bulk density (Dust_Refined_2) refinements individually and in combination (Dust_Refined_3). The Dust_Refined_3 normalized mean bias of PM10 was −30.65 % for the 2010 SDS event, which was lower in magnitude compared to Dust_Refined_1 (−41.18 %) and Dust_Refined_2 (−49.88 %). Indeed, Dust_Refined_3 improved the simulated aerosol optical depth (AOD) value during significant dust cases, e.g., in March 2005, March 2006, and April 2009. Dust_Refined_3 also showed more clearly that, in March 2010, a “double plume” (i.e., one plume originating from the Taiwan Strait and the other from the western Pacific) separated by the Central Mountain Range (CMR) of Taiwan affected dust transport on the island of Dongsha in the SCS. On 15–21 April 2021, both CMAQ simulations and satellite data highlighted the influence of Typhoon Surigae on dust transport to downwind Taiwan and the western Pacific Ocean (WPO). The CMAQ Dust_Refined_3 simulations further revealed that many dust aerosols were removed over the WPO due to Typhoon Surigae. Hence, the model indicated a near-zero dust particle concentration over the WPO, which was significantly different from previous dust transport episodes over the Taiwan region. Therefore, our study suggested an effective method to improve dust management of CMAQ under unique topographical and meteorological conditions.

Effect of different leaching solutions on removal efficiency of K, Na, and Zn elements from blast furnace bag dust

ABSTRACT As a by-product of steel production, the efficient treatment of metallurgical dust is an important research topic in metallurgical industry. To recycle blast furnace bag dust into metallurgical process, harmful elements (K, Na and Zn) need to be removed. By using different acidic solvents and leaching conditions to treat the bag dust, the best leaching conditions of K, Na and Zn elements were explored. The results show that the optimal leaching conditions of harmful elements in water solution are: 4 ml/g liquidsolid ratio, 50°C temperature, 30 min stirring time. Water solution has a certain removal effect on K and Na elements but has little effect on Zn content. The leaching rates of K, Na and Zn were improved by using ammonia, hydrochloric acid and sulfuric acid solutions. Sulfuric acid with a concentration of 2 mol/L has the best removal efficiency for K, Na and Zn elements in bag dust, and the maximum removal rates of K, Na and Zn are 82.3%, 81.5% and 88.7%, respectively. Through this study, the potential to leach K, Na and Zn elements from bag dust was demonstrated, and an experimental basis for the resource utilization of bag dust in metallurgical process was provided.

Selective removal of zinc and lead from electric arc furnace dust by chlorination–evaporation reactions

Re-melting of scrap in an electric arc furnace (EAF) results in the accumulation of filter dust from off-gas treatment that predominantly consists of iron and zinc oxides. Filter dust is classified as hazardous waste due to its high contents of potentially toxic or ecotoxic elements such as Pb, Cr, Cd, and As. A promising processing route for this waste is selective chlorination, in which the non-ferrous metal oxides are chlorinated and selectively evaporated in form of their respective chlorides from the remaining solids via the process gas flow. Here, we investigate stepwise thermochemical treatment of EAF dust with either waste iron(II) chloride solution or hydrochloric acid at 650, 800, and 1100 °C. The Zn and Pb contents of the thermochemically processed EAF dust could be lowered from 29.9% and 1.63% to 0.09% and 0.004%, respectively. Stepwise heating allowed high separation between zinc chloride at the 650 °C step and sodium-, potassium-, and lead-containing chlorides at higher temperatures. Furthermore, the lab-scale results were transferred to the use of an experimental rotary kiln highlighting the possibilities of upscaling the presented process. Selective chlorination of EAF dust with liquid chlorine donors is, therefore, suggested as a potential recycling method for Zn-enriched steelworks dusts.

Quantitative and qualitative composition of solid particles released into the atmosphere when burning coal (a case study from a brick factory of Uzbekistan)

The fight against atmospheric air pollution by combustion products of natural coal, in particular coal ash, is an urgent task. The most refined definition of the qualitative and quantitative characteristics of coal ash, taking into account the specifics of the technological process for the production of burnt bricks, will serve to identify and justify the technological process and the main parameters of the dust and gas treatment device (PGOU) for use in the production of building materials that involve the use of natural coal as fuel.

Quantitative and qualitative composition of solid particles released into the atmosphere when burning coal (a case study from a brick factory of Uzbekistan)

The fight against atmospheric air pollution by combustion products of natural coal, in particular coal ash, is an urgent task. The most refined definition of the qualitative and quantitative characteristics of coal ash, taking into account the specifics of the technological process for the production of burnt bricks, will serve to identify and justify the technological process and the main parameters of the dust and gas treatment device (PGOU) for use in the production of building materials that involve the use of natural coal as fuel.

Flue Dust Behaviour in FSF - Arsenic Condensation in Offgas Line Conditions

The suspension smelting oxidation step has favourable conditions to generate chemical flue dust from the low-boiling elements of the feed mixture due to the high particle temperatures in the reaction shaft where combusting sulphide mineral particles reach temperatures above the melting point of magnetite. Arsenic, antimony, lead, and zinc are common impurity elements of high volatility in copper concentrates. They tend to accumulate in the flue dust due to the high volatility and closed mode of the flue dust circulation practiced in most industrial smelting-converting processes. Then, the only outlets for the volatile impurities are the anodes and the discard slag. A separate flue dust treatment for impurity removal is an option but it creates an additional step for the smelting plant and cost in the processing. When the concentrate grades decrease, and their impurity levels rise this outlet for the trace elements may become necessary. The arsenic condensation mechanisms in dust-free conditions in the copper flash smelting process gas train have been recently studied in SO2-air-N2 gas mixtures. It seems that the formation mechanism of arsenic-containing dust deposits is kinetically constrained, and their chemistries are influenced by the condensation temperature and atmosphere.

Research on treatment of indoor fine dust using a green plant model combined with negative ions

Air pollution is a growing environmental problem worldwide. Compelling epidemiological evidence shows that people spend more than 80% of their time indoors, and extensive studies have shown that indoor air pollution has an equal or greater impact on health when compared. with the surrounding environment. This article determines that the level of indoor fine dust pollution with PM2.5 and PM10 is quite high and changes over the seasons. Winter has the highest concentration, specifically PM2.5 accounting for 54g/m3, PM10 accounting for 97g/m3. The model for treating indoor dust with negative ions initially showed positive results with an efficiency of 70-84.8% at a device height of 75cm. This is the basis for further detailed research on fine dust treatment with negative ions.

Extracting zinc from ironworking dust having a high zinc content by vacuum silicothermic reduction

Zinc dust having a high ZnO content can be obtained after the preliminary treatment of zinc-bearing dust generated by the iron and steel industry by using a rotary kiln. However, this material has a high concentration of chloride salts that can affect the hydro-metallurgical extraction of metallic zinc. The present study used a vacuum distillation-vacuum thermal reduction process to recover zinc metal from this dust. This process first separated chloride and PbO by vacuum distillation and then extracted metallic zinc via the vacuum silicothermic reduction of ZnO. The results show that high-purity ZnO was prepared by vacuum distillation using the original zinc dust as a raw material. Both alkali metal chlorides and PbO in the dust could be removed with greater than 99 % efficiency by vacuum distillation at 1000 °C. Following this step, the slag contained more than 80 wt% Zn but less than 0.01 wt% chlorine and PbO. The vacuum thermal reduction process used the slag obtained from distillation as the raw material together with ferrosilicon alloy as a reducing agent. ZnO was reduced above 1000 °C and the recovery of this oxide exceeded 99 % using a reduction temperature of 1200 °C, reduction time of 2 h, and ferrosilicon mass ratio of 0.27. The main phase in the slag after reduction was SiO2 and the ZnO concentration was below 1 wt%, indicating a purity greater than 99 %. This method can realize the separation, recovery, and reuse of zinc-bearing dust to maximize the value-added utilization of this resource.

Preparation of nano zinc oxide by alkaline treatment of industrial zinc oxide dust

A new method for the preparation of nano-zinc oxide was proposed for the effective use of zinc oxide dust (ZOD) containing complex impurities recycled and processed from local plants. Fe2+, Fe3+, Ca2+, Mg2+, Mn2+, Cu2+, and Pb2+, Sn4+, Al3+, Si4+, Bi3+ were selectively extracted from ZOD by alkaline leaching combined with precursor firing process. The effects of thermodynamic analysis of ZOD, Sodium hydroxide(NaOH) concentration(2–8 mol/L), leaching time (15–75 min), autothermal temperature of leaching reaction (43–70 °C), leaching liquid/solid ratio (L/S:5–25 mL/g), and pH were investigated during leaching process. Thermogravimetry-differential thermogravimetry (TG-DTG) analyses were carried out on Zinc carbonate hydroxide (Zn5(CO3)2(OH)6) precursor. In addition, the effects of calcination temperature(400–700 °C) and holding time (1.5–4.0 h) of precursors on average particle size of nano-ZnO were also studied. The results showed the leaching rate of Zn2+ reached 98.35% under the optimum conditions as: NaOH concentration of 6 mol/L, L/S of 20 mL/g, and leaching time of 60 min. Separation rates of Pb2+, Sn4+, Al3+, Si4+ reached 94.63%, 85.08%, 98.03%, 91.48%, respectively at pH = 5.5. Zn5 (CO3)2(OH)6 nano precursors were obtained at pH = 7–8. After the precursor of zinc carbonate was calcined at 400–600 °C for 2 h, high purity (99.53%) nano-zinc oxide was obtained with a particle size of 20 nm, a specific surface area of 23.84 m2/g, a porosity of 32.66%, and a zeta potential of −13.2 mV. This article provides an alternative new idea for the green and comprehensive utilization of industrial ZOD dusts with complex compositions.

Eco-friendly treatment of copper smelting flue dust for recovering multiple heavy metals with economic and environmental benefits

Handling flue dust in an environmentally friendly manner has become an urgent task for pollution prevention in the copper industry. Here, driven by the low-carbon notion, we report a process that enables the selective retrieval of multiple metals (As, Cu, Pb, Zn, and Bi) from copper smelting flue dust (CSFD). This process employed low-temperature roasting to separate arsenic from heavy metals, thereby eliminating the tedious separation steps required by existing processes. Subsequently, Zn and Cu were dissolved in water, while Pb and Bi were left as a solid residue. We achieved 98.23% extraction of Cu via Zn cementation at a micro-voltage of 0.50 V. Utilizing the difference in solubility, Bi was selectively dissolved from the residue using a NaCl-HCl medium, which enabled the subsequent production of metallic Bi through electrowinning. Finally, more than 99% of Pb in the solid was reduced to elemental Pb by mechanochemical reduction. Through optimized process conditions, high-purity As2O3 (99.04%), lead ingot (99.95%), metallic copper (94.16%), and bismuth (99.20%) were obtained. Our economic assessment revealed significant advantages, demonstrating the industrial feasibility of this process. Consequently, this study presents an effective and cost-efficient system for CSFD disposal while minimizing the environmental impact and fostering a circular economy.

Aeolian dust and hydro-biological characteristics: Decoding dust storm impacts on phytoplankton in the northern Arabian Gulf

Aeolian dust is an essential source of growth-limiting nutrients for marine phytoplankton. Despite being at the core of the Global Dust Belt, the response of the Arabian Gulf ecosystem to such atmospheric forcing is rarely documented. Here, the hydro-biological effect of mineral dust was studied in the northern Arabian Gulf (NAG) off Kuwait through monthly water sampling (December 2020 to December 2021), dust-storm follow-up sampling, and mineral dust and nutrient addition in-situ experiments. The multivariate analysis of oceanographic data revealed pronounced hydro-biological seasonality. The mineral dust deposition during two severe dust storm events in March and June 2021 showed a spatially varying effect of dust on coastal waters. The dust storms elevated the surface dissolved iron levels by several magnitudes, increased the dissolved inorganic nitrogen and phosphorous levels, changed their stoichiometry, and offset the hydrobiological seasonality. In the microcosms, dust input temporarily reduced phytoplankton phosphorous limitation in a dose-dependent manner when mesozooplankton (copepods) grazing was minimal. The microphytoplankton response to mineral dust inputs was comparable to that with nitrogen and phosphorous treatment. While Both treatments increased diatom size structure and biomass, the abundance of single-celled diatoms was comparatively higher in dust treatment. Multivariate analysis indicated that dust deposition alters the hydrographical properties of the surface ocean during dust storm events. The effects, though transient, were traceable for 3–16 days post-storm in coastal waters. The response of the summer phytoplankton to these changes, if delayed or muted, should be interpreted with caution given the summer water column stratification, the high nitrogen: phosphorous ratio and the low phosphorous solubility of aerosol dust, and the complex pelagic microbial food web interactions in the NAG. This study thus underlines the importance of a multivariate approach in documenting the ecological implications of Aeolian dust storms on marine environments closer to the dust source regions.

A Study on the Development of Waste Heat Recovery Equipment for Waste Heat Recovery and Fine Dust Treatment

A Study on the Development of Waste Heat Recovery Equipment for Waste Heat Recovery and Fine Dust Treatment

Thermal treatment of lead-rich dust to improve fresh characteristics and adsorption behavior of autoclaved geopolymer for methylene blue dye removal

Thermal treatment of lead-rich dust to improve fresh characteristics and adsorption behavior of autoclaved geopolymer for methylene blue dye removal

Hydrogen reduction process for zinc-bearing dust treatment: Reduction kinetic mechanism and microstructure transformations in a novel and environmentally friendly metallurgical technique

The iron and steel sector generates 80 million tons of zinc-containing dust annually, traditionally treated using carbon-based pyrometallurgical processes, which have significant drawbacks, including large carbon emissions, high energy consumption, and low production value. To address the above issues, a green hydrogen reduction method was developed for zinc-bearing dust treatment. This study examined the thermodynamics, reduction kinetics, and phase transformation during the process, revealing that at 800 °C, the hydrogen partial pressure for zinc oxide reduction is only 45.56 %. The direct reduction of zinc-containing dust pellets with hydrogen reveals that the limiting step of iron oxide and zinc reductions both are interfacial chemical reaction control at the reduction temperature of 800–950 °C, with an apparent activation energy of 16.42 kJ/mol and 71.39 kJ/mol. The kinetic mechanism indicates that reducing iron and zinc oxides is more accessible in a hydrogen reduction system, with lower apparent activation energies than carbothermal reduction. Consequently, hydrogen reduction offers a more efficient and environmentally friendly solution for treating zinc-bearing dust.