Weight Of Dust Research Articles

Functional performance of composite nonwoven fabrics having varying packing density of constituent fabrics under different operating conditions

In this study, two types of composite nonwoven fabrics having gradient and inverse gradient of packing density of constituent fabrics were developed and tested for their filtration performance at different operating conditions. These composite nonwoven fabrics were produced by using sequential punching technique by varying the punch densities of the constituent fabrics. Box–Behnken three factors three level design was used, and air velocity, weight of dust fed, and operating time were considered as variables. An instrument for gauging the filtration performance of the composite nonwoven filters was designed and fabricated. The packing density of nonwoven fabrics was measured by using the X-ray computed tomography (XCT) technique. The results depicted those composite nonwoven fabrics having inverse gradient of packing density of constituent fabrics outperformed the composite nonwoven fabrics having gradient of packing density in terms of filtration performance with variable operating conditions.

Utilisation of dolomite dust with pure epoxy resin: Physical, mechanical and erosion wear analysis

AbstractUtilization of inorganic waste, if included in composite material, can be beneficial in reducing the accumulation of waste, which could help in resolving problems of disposal. beside from that, incorporating waste into composite materials also reduces the overall cost of the composites as a whole. The study examines the impact of dolomite content on the mechanical properties of the composites. Increasing the amount of dolomite in the composite significantly weakens its flexural strength, falling from 42.4 MPa at 0 % dolomite to 28.7 MPa at 15 % dolomite. Composite tensile strength also decreases by up to 25.8 % with rising dolomite dust concentration. Additionally, dolomite increases interlaminar shear strength (ILSS), with EDH15 composites showing the highest improvement. Dolomite dust in epoxy‐based composites increases the hardness value from 85 HRL to 95 HRL with an increase in dolomite dust content. The erosion test perform on air jet tester shows lowest wear rate was achieved under the following conditions: 10 % dolomite dust weight, 30° impingement angle, 10 m s−1 impact velocity, and 150 μm erodent size. Furthermore, scanning electron microscopy was used to examine the damaged, eroded surfaces for assumed wear mechanisms.

Effects of elevated temperatures and cooling regimes on the waste andesite dust-based geopolymer mortars

In this study, the geopolymer mortar mixtures were manufactured by activating andesite stone cutting waste dust with sodium silicate. The sodium silicate content in the mixtures was determined to contain 6%, 8% and 10% Na2O by weight of waste andesite dust (WAD). The produced mixtures were subjected to thermal curing at three different temperatures (60 ºC, 75 ºC and 90 ºC), and in two different periods (8 hours and 24 hours). Flexural strength (fs) and compressive strength (fc) tests of 1, 28 and 56 days were carried out on the specimens obtained from the geopolymer mortar mixtures. The effects of Na2O content, thermal curing temperature and time on the strength values of the geopolymer mortars were investigated. Moreover, the geopolymer mortar samples produced with 8 hours of thermal curing were exposed separately to 400 ºC, 600 ºC and 800 ºC. The specimens, which were kept for 1 hour at 400 ºC, 600 ºC and 800 ºC, were exposed to three different cooling conditions (slow-cooled in air, fast-cooled in air and water-cooled). The fs and fc tests were carried out on the cooled geopolymer mortars, and the effects of high temperatures and cooling conditions on the strength properties of the geopolymer mortars were evaluated. In addition, the changes in the microstructures were examined by performing XRD and SEM/EDAX analyses on the selected geopolymer mortars. The fs and fc values of the water-cooled geopolymer mortars significantly decreased.

Direct generation of DBPs from city dust during chlorine-based disinfection

Chlorine-based disinfectants, such as sodium hypochlorite, are extensively used in our daily lives. In particular, during the recent Covid-19 pandemic and post-pandemic period, excessive amounts of chlorine-based disinfectants were used both indoors and outdoors to interrupt virus transmission. However, the interaction between disinfectants and city dust during the disinfection process has not been sufficiently evaluated. In this study, we conducted a comprehensive investigation into the intrinsic characteristics (e.g. morphology, size, elemental composition, and organic content, etc.) of dust collected from various indoor and outdoor areas. The results showed that the organic carbon content of indoor dust reached 6.14 %, with a corresponding measured dissolved organic carbon value of 4.17 ± 0.23 mg/g (normalized to the dust weight). Concentrations of regulated DBPs, resulting from the interaction between dust and NaClO, ranged from 57.78 ± 2.72 to 102.80 ± 22.63 µg/g for THMs and from 119.18 ± 6.50 to 285.14 ± 36.95 µg/g for HAAs (normalized to the dust weight). More significantly, using non-target analysis through gas chromatography quadrupole time-of-flight mass spectrometry (GC-qTOF-MS), we identified a total of 68, 89, and 87 types of halogenated DBPs from three typical indoor and outdoor sites (R-QH, C-JS, and W-BR, respectively). These unknown DBPs included compounds with higher toxicity compared to regulated DBPs. These findings highlight that city dust is a significant source of DBP generation during chlorine-based disinfection, posing potential harm to both the ecological environment and human health.

Investigation of the usability of industrial mining wastes in agriculture

In this study, the usability of the mixtures consisting of lignite coal taken from Tekirdag region and marble and travertine wastes taken from the marble factory in Gumushane region in local bean (Kelkit) cultivation was researched. First, control samples were created using only humus soil without coal, marble, or travertine dust. Then, for each coal or coal waste, coal/coal waste—waste marble dust and coal/coal waste—travertine dust mixtures were formed. These mixtures were obtained by mixing 25%, 50%, 75%, and 100% by weight of coal and 25%, 50%, and 75% by weight of marble and travertine dust. Afterwards, local beans were planted in these mixtures and their development was followed under laboratory conditions. Additionally, temperature and humidity values were recorded at certain intervals, pH and heavy metal analysis measurements were made on the mixtures before and after bean planting, the height and leaf measurement of the beans grown and the number of beans grown in these beans were also followed, and chlorophyll analysis was performed on the bean plants grown in these mixtures. As a result, 50% Coal-3D + 50% Travertine mixture had the maximum length increase, that 25% Coal Waste (Powder)-K3 + 75% Marble mixture had the highest number of beans, and that 50% Coal Waste -AK + 50% Marble mixture had the maximum leaf formation. In these mixtures, maximum 12 beans were grown and maximum 93 leaves were formed. Also, the bean plant was grown in all mixtures. The chlorophyll contents were at least as much as the values of the beans grown only in soil. However, heavy metal values do not exceed the permissible limit values in soil.

Green Synthesis of the Effectively Environmentally Safe Metakaolin-Based Geopolymer for the Removal of Hazardous Industrial Wastes Using Two Different Methods.

Untreated wastewater pollution causes environmental degradation, health issues, and ecosystem disruption. Geopolymers offer sustainable, eco-friendly alternatives to traditional cement-based materials for wastewater solidification and removal. In this study, we investigate how wastewater containing organic and inorganic pollutants can be removed using geopolymer mixes based on metakaolin incorporation with cement kiln dust as an eco-friendly material. The present investigation compares the efficacy of two different techniques (solidification and adsorption) for reducing dye contaminants and heavy metals from wastewater using a geopolymer based on metakaolin incorporation with cement kiln dust. This study investigated the adsorption capacity of a geopolymer based on metakaolin incorporating two different ratios (20% and 40% by weight) of cement kiln dust (MC1 and MC2) for the reactive black 5 dyeing bath effluent (RBD) only and in a combination of 1200 mg/L of Pb2+ and Cd2+, each separately, in aqueous solutions under different adsorption parameters. The results of the adsorption technique for the two prepared geopolymer mixes, MC1 and MC2, show that MC1 has a higher adsorption activity than MC2 toward the reactive black 5 dyeing bath effluent both alone and in combination with Pb2+ and Cd2+ ions separately. The study also looked at using MC1 mix to stabilize and solidify both the dyeing bath effluent alone and its combination with 1200 mg/L of each heavy metal individually inside the geopolymer matrix for different time intervals up to 60 days of water curing at room temperature. The geopolymer matrix formed during the process was analyzed using FTIR, SEM, and XRD techniques to examine the phases of hydration products formed. The results showed that MC1 effectively adsorbs, stabilizes, and solidifies the dying bath effluent for up to 60 days, even with high heavy metal concentrations. On the other hand, geopolymer mixes showed an increase in mechanical properties when hydration time was increased to 60 days. According to our findings, the type of geopolymer developed from metakaolin and 20 wt.% cement kiln dust has the potential to be employed in the treatment of wastewater because it has good adsorption and solidification activity for the reactive black 5 dye effluent alone and for a mixture of dye pollutants with both Pb2+ and Cd2+ ions separately. Our results have significant implications for wastewater treatment and environmental remediation efforts, as they offer a sustainable solution for managing hazardous waste materials.

Daily prediction method of dust accumulation on photovoltaic (PV) panels using echo state network with delay output

Dust accumulation over time can be one of the main causes of uncertainty in the output of photovoltaic (PV) systems. In order to better understand these losses, this paper established a daily dust accumulation prediction model for PV panels based on the delay output echo state network (DESN). A pigeon-inspired optimization (PIO) algorithm with adaptive Cauchy (AC) mutation strategy was proposed, which can optimize the reservoir parameters (such as leakage rate, spectral radius, and input scaling) of DESN, shorten the solution time, and improve search speed. Based on typical meteorological and air quality data, as well as daily accumulated dust weight recorded from the experimental platform, model training and testing were carried out. According to the Pearson correlation coefficient, the relationship between the environment parameters (humidity, wind speed, wind direction, PM2.5, PM10, and rainfall) and the dust accumulation was obtained. The results show that the prediction accuracy of AC-PIO-DESN is better than other methods for meteorological and air quality data. The mean absolute percentage error (MAPE) for humidity, irradiance, PM2.5 and PM10 were 4.0743%, 4.4958%, 10.6231% and 12.8402%, respectively. In addition, the proposed daily dust prediction model has good robustness for 10-day samples, with an average relative error ranging from 0.65% to 54%. This method can provide data support for grid scheduling and PV panel cleaning strategy of PV power plants.

Metal recovery from spent Ni-Mo-V hydrodesulphurisation catalyst in oxalic acid media by mechanochemical treatment

ABSTRACT The spent hydrodesulphurisation (HDS) catalysts used for the removal of sulphur from petroleum products can be a secondary source of especially Mo and V. This work describes the mechanochemical extraction of Mo, Ni, V, Al and P from spent petrochemical catalysts in H2C2O4. The effect of rotational speed, H2C2O4 concentration, ball to the dust weight ratio and solid-to-liquid ratio on the extraction rate of roasted spent catalyst was investigated. The reactions proceed with an increase in H2C2O4 concentration for extraction of Mo, V and P. The reactions for the extraction of Mo, V and P proceed with an increase in H2C2O4 concentration, but the dissolution behaviour of Ni is different from other elements. 87% of Mo, 44% of Ni, 82% of V, 36% of Al and 78% of P were extracted at optimum experimental conditions.

Investigating the Effect of Dust on the Rate of Photosynthesis and Air Pollution Tolerance Index of the Leaves of Ziziphusspina-christi (L.) Willd. in the City of Ahvaz

Background & Aims: Dust is one of the phenomena affecting the environment’s quality. The change in the vital indices of plant species is one of its important effects. The present study was conducted to investigate the effect of dust on the rate of photosynthesis and air pollution tolerance index (APTI) of the leaves of Ziziphus spina-christi (L.) Willd. in the city of Ahvaz in 2020. Materials and Methods: A number of 10 Z. spina-christi (L.) Willd. trees were selected in each municipal district of Ahvaz metropolis. From each tree, one leaf sample was selected in the 4 main geographical directions, i.e., 4 samples from each tree species; overall, 40 leaf samples were collected in the whole region and sent to the laboratory to investigate the level of dust particles deposited in the four seasons of the year. Photosynthesis was measured based on the amount of chlorophyll by a spectrophotometer, and the APTI was calculated using Agbaire et al.’s method. Results: The results of measuring the weight of dust deposited on the leaves of Z. spina-christi (L.) Willd. trees in the city of Ahvaz showed that the greatest amount of dust was deposited on the leaves in the geographical north direction. The highest rate of photosynthesis was in the fall (53.76), and the lowest was in the spring (35.97). The mean APTI score of Z. spina-christi (L.) Willd. species in Ahvaz was 4.77. Conclusion: These results indicate that this species has a favorable APTI against environmental pollutants, including dust. In general, the results of the present study confirm the significant association of the dust deposited on the leaves of Z. spina-christi (L.) Willd. with the rate of photosynthesis and the APTI.

Role of dust loading in dynamic transport of semi-volatile organic compounds (SVOCs) into house dust: From multilayer to monolayer

House dust is an important transfer and storage medium of semi-volatile organic compounds (SVOCs) in indoor environments. Dust loading (dust weight per surface area) has been identified as a key factor affecting SVOC transport into dust. As the increment of dust loading, house dust can be classified as monolayer and multilayer dusts. Most of existing studies have only investigated the multilayer dust though the monolayer dust is also ubiquitous on indoor surfaces, precluding the comprehensive explanation of dust loading effects. Therefore, this study proposed a mass transfer model to describe SVOC transport into house dust by differentiating SVOC diffusion distance in monolayer and multilayer dusts. High consistence between model predictions and measurements justified the model performance. Characteristic parameters of SVOCs in house dust, dust-air partition coefficient (Kd) and diffusion coefficient (Dd), were determined by fitting the model to the measurements. Further analysis indicated that: (1) SVOC transport mechanism in monolayer dust (dust size-dependent) was different from that in multilayer dust (dust loading-dependent), and (2) dust loading (in the range of 2.55–30 g/m2) might have insignificant effects on Kd. This study should be helpful for the deep understanding of SVOC transport into house dust and the accurate exposure assessment of indoor SVOCs.

Utilization of Basaltic Quarry Dust as a Partial Replacement of Cement for Hollow Concrete Block Production

This research was conducted to examine the potential of basaltic crusher dust as a partial replacement for Portland Pozzolana cement in hollow concrete block (HCB) production. Quarry dust is one of the waste materials abundantly available and pozzolanic material in the quarry industry. In doing so, physical tests of cement pastes and hollow concrete blocks of different classes, i.e., A, B, and C, were produced by partially replacing the cement content with 10%, 20%, 30%, and 40% by weight of basaltic crusher dust using vibrating block molding machine. The units without basaltic crusher dust (0%) serve as a control variable. The cement pastes were examined for consistency and setting time, and the blocks produced were tested to determine their compressive strength, water absorption rate, and density. Furthermore, the possible cost advantages of using basaltic crusher dust as a partial replacement of cement in the hollow concrete block were analyzed. The result indicates that the experimental HCB of classes A and C surpassed the required standard of compressive strength, water absorption, and density specified by the Ethiopian standard ES 596:2001; whereas, the compressive strength of class B fails at 40% cement replacement. It was concluded that hollow concrete blocks of classes A and C with up to 40% replacement and class B with up to 30% replacement can be used for load-bearing walls and save the e cost of hollow concrete blocks with comparable properties.

Characterization of dust produced during the 2021 first campaign in EAST tokamak

• The dust collected from 2021 first experimental campaign in EAST was characterized and analyzed. • By using the diagnostic observation window, dust was collected during the campaign for several times. The local dust production rate decreases as the plasma operation goes. • Ferromagnetic dust with the shape of strips, flakes, irregular blocks and spheroids has been found in EAST. Dust has been collected and characterized by various methods during the 2021 first experimental campaign in EAST tokamak. It was found that the weight of the in-vessel dust collected at the mid-plane port varied from about 265 mg to about 966 mg. And the dust appeared mainly in the shape of spheroids, flakes, stripes and irregular-shaped particles with the sizes ranging from micrometers to several millimeters. The dust consisted of different elements, which was from the wall-conditioning, erosion of plasma-facing materials (PFMs) as well as the flaking of deposits. The dust collected from the lower port K contained different elements from those collected from the in-vessel port K, with more Fe in the lower port and more Li in the vacuum vessel. The ferromagnetic dust with different shape has been found, and different shape has different O content and size. By using the diagnostic observation window, dust was firstly collected during the campaign and the local dust production rate is calculated, which is found to decrease as the plasma operation goes.

Aerosol Mineralogical Study Using Laboratory and IASI Measurements: Application to East Asian Deserts

East Asia is the second-largest mineral dust source in the world, after the Sahara. When dispersed in the atmosphere, mineral dust can alter the Earth’s radiation budget by changing the atmosphere’s absorption and scattering properties. Therefore, the mineralogical composition of dust is key to understanding the impact of mineral dust on the atmosphere. This paper presents new information on mineralogical dust during East Asian dust events that were obtained from laboratory dust measurements combined with satellite remote sensing dust detections from the Infrared Atmospheric Sounding Interferometer (IASI). However, the mineral dust in this region is lifted above the continent in the lower troposphere, posing constraints due to the large variability in the Land Surface Emissivity (LSE). First, a new methodology was developed to correct the LSE from a mean monthly emissivity dataset. The results show an adjustment in the IASI spectra by acquiring aerosol information. Then, the experimental extinction coefficients of pure minerals were linearly combined to reproduce a Gobi dust spectrum, which allowed for the determination of the mineralogical mass weights. In addition, from the IASI radiances, a spectral dust optical thickness was calculated, displaying features identical to the optical thickness of the Gobi dust measured in the laboratory. The linear combination of pure minerals spectra was also applied to the IASI optical thickness, providing mineralogical mass weights. Finally, the method was applied after LSE optimization, and mineralogical evolution maps were obtained for two dust events in two different seasons and years, May 2017 and March 2021. The mean dust weights originating from the Gobi Desert, Taklamakan Desert, and Horqin Sandy Land are close to the mass weights in the literature. In addition, the spatial variability was linked to possible dust sources, and it was examined with a backward trajectory model. Moreover, a comparison between two IASI instruments on METOP-A and -B proved the method’s applicability to different METOP platforms. Due to all of the above, the applied method is a powerful tool for exploiting dust mineralogy and dust sources using both laboratory optical properties and IASI detections.

Abrasion testing of anti-reflective coatings under various conditions

PV modules can quickly accumulate a light hindering layer of dust on the front glass, especially in arid regions. This soiling needs to be removed regularly, often using dry brushes as water is usually not easily available to wash the panels. Repeated cleaning negatively affects the anti-reflective coating (ARC) on the glass, leading to permanent transmittance loss and therefore a reduced energy yield. Within this work, two different ARCs and a reference glass are investigated regarding their resistance against harsh abrasion with a dry linear brushing abrasion cycle tester for laboratory and mobile use. The reduction of the spectral transmission is studied as a function of brushing cycles (0, 100, 1000) and integral relative transmittance loss has been calculated. Furthermore, a sensitivity analysis is performed for additional test parameters being type of dust, brush speed and weight. In particular, the type of dust shows a significant influence on the abrasion behavior. Less influential are the brush weight and the speed in the range used here. The dusts used in this setup were Feldspar, Calcite, Corundum and Arizona test dust in different particle size distributions. Using the hard Corundum dust, 1000 brush cycles lead to a relative loss in transmittance of about 3%. The application potential of the presented linear abrasion test for quality assessment and benchmarking of commercial glass coatings will be discussed. In particular, the implementation of region-specific test dusts in laboratory test procedures is of high interest for further standardization activities. • Linear brush abrasion test setup was used to test two different Anti-Reflective Coatings (ARCs). • Huge differences in transmittance loss between the coatings detected. • Investigation of the impact of test parameters brush speed, weight, brush cycles and type of dust. • Dust type and hardness are the most important influencing factors on the transmittance loss while brush speed and weight show no significant impact. • Method can be used for the development of site-specific ARC.

Effect of Dust Accumulation on the Performances of Solar Panels in Static and Tracking Systems in Bauchi Metropolis of Nigeria

The research aimed at comparing the effect of dust accumulation on the performances of solar PV modules in static position and on a tracking system within Bauchi metropolis of Nigeria , during the harmattan season –November to December. Dust deposition on the surface of PV panel reduces the conversion efficiency by absorbing and preventing the Solar radiation from reaching the cells of the panel. This necessitated the need to develop a reliable tool to relate energy production from solar cells with respect to dust deposition on both static and solar tracking PV modules. A test bed was designed for the field measurement of output current, voltage, temperature and dust weight data from the two PV modules.” Centsys” polycrystalline solarpanels () was used for the research. A statistical technique involving regression analysis in SPSS software was used to correlate between the various measured data from the test bed to predict the effect of dust accumulation on the surface of each module, which will enable solar power installers to take necessary measures for improving the PV module’s conversion efficiency during the period under review. The research result showed that the effect of dust on the tracking solar PV moduleis less significant compared to the static panel, giving the former a better conversion efficiency.

Value-added waste substitution using slag and rubber aggregates in the sustainable and eco-friendly compressed brick production

The current study aimed to analyse the viability of incorporating the post cryogenic discarded rubber and the air-cooled slag as an aggregate in partial replacement of stone dust in fly ash bricks production. A range of mechanical, non-destructive, and microstructural tests was performed on bricks thus produced by incorporating rubber and slag aggregates in various dosages (i.e., 5, 10, 15, 20 and 25% by stone dust weight). The result revealed that the compressive strength dropped from 71 to 43 % in the case of rubber aggregate replacement. Morphology study confirms that the rubber aggregates resulted in the porous microstructure of the bricks and leads to lesser unit weight and lighter structure. The rubber may be used as a lightweight aggregate in the brick possibly as it reduces the density of the final product. However, the use of rubber in bricks needs to be cautiously designed to get hold of productive solutions at the end. The findings demonstrate that the copper slag substitution of up to 15%, found to be enhanced the strength properties and it will be a better choice for low-cost construction as a promising alternative construction material.

Environmental impact analysis and enhancement of factors affecting the photovoltaic (PV) energy utilization in mining industry by sparrow search optimization based gradient boosting decision tree approach

This paper proposes a hybrid technique to recover the efficiency of solar photovoltaic (PV) energy system from the environmental impacts. The proposed technique is the combination of both sparrow search algorithm and gradient boosting decision tree; thus it is named SSA-GBDT method. The purpose of the proposed technique is to improve the efficiency of solar PV energy system and maximization of power removal from PV arrays. The PV module voltage, current and power is measured by SSA and it creates possible database offline. Database with electric parameters is utilized to develop the model online using GBDT. The data set contains some parameters like particle size and dust weight input and maximal power value output variables. Then, the proposed technique is implemented on the MATLAB/Simulink platform and the performance is compared with existing techniques. The performance of PV under normal condition, dust accumulation condition, water drops condition and partial shading conditions are the considered cases. In the cases, photovoltaic reference irradiance and temperature, PV current, voltage and generated power, active and reactive power, grid current and voltage, inverter power is also evaluated. The efficiency comparison of PV power for solution processes like ANN, GBDT, SSA and proposed system are also analyzed.

Ferroalloy production from ferrosilicon manganese dusts

The article presents the results of studies on the influence of time, the amount of steel shavings and coke on the electric melting of ferrosilicon manganese dusts to obtain a ferroalloy. The research was carried out by the method of rotational planning of the second order (Box-Hunter plans) and by electric smelting of dust in laboratory ore-thermal arc furnace. Dust from the production of ferromanganese by LLP Taraz Metallurgical Plant, coke and steel shavings were used during the research. It was determined that to achieve αSi≥70%the process must be carried out in the presence of 25% coke and 8.1-9% steel shavings from the mass of dust for 55.8-60 minutes, to achieve αMn in an alloy of 80-85% the process must be carried out in the presence of 25% coke, 5.7-9.0% steel shavings for 41.2-54.4 minutes. When melting the charge containing 75.2% of dust, 18.8% of coke, 6% of steel shavings, within 60 minutes the weight of the ferroalloy was 258 g (38.8% of the weight of the charge or 51.6% of the weight of dust). The degree of extraction of manganese into the alloy was 82.3%, silicon - 66.1%. The resulting ferroalloy belongs to ferrosilicon manganese of the FeMnSi12 grade.

Loss Assessment of Stored Maize at Different Storage Durations and Maize Weevil Densities

Aims: The extent of stored grain losses depends on varieties and duration of storage, and most of the quantitative losses are attributed to insect pest infestations. The study was conducted to determine the damage caused by Sitophilus zeamais on maize stored at different durations.
 Methodology: Sitophilus zeamais at four varying population densities (5, 10, 15, 20 adults) and four storage durations (30, 60, 90 and 120 days) reared on 200 g sample of Jeka maize variety was kept in glass jars covered with muslin cloth in a 4 x 4 factorial fitted in a completely ramdomised design with four replicates at room temperature for 120 days.
 Results: Weight loss, seed damage and weight of dust caused by S. zeamais on maize seeds at 5-insect and 20-insect levels were statistically similar at 30 and 120 days but show significant difference at 60 days after storage. Sitophilus zeamais population continued to grow exponentially on maize grains after 120 days of storage, indicating that factors are not limiting, thereby causing significant losses to stored grains. Temperature and relative humidity were found to affect insect population growth positively (r = 0.73 and r = 0.70, respectively).
 Conclusion: The study concluded that S. zeamais, which is a major pest in The Gambia, in the absence of control measures at any number of infestations greater than 5 weevils could result to severe damage to stored seeds.

Recovery of Zn as ZnO from Steelmaking Waste Materials by Mechanochemical Leaching, Solvent Extraction, Precipitation, and Thermal Decomposition Route

A large amount of electric arc furnace dust (EAFD) is produced as hazardous waste materials during steelmaking in electric arc furnace. EAFD includes a considerable amount of zinc. Recovery of Zn as ZnO from EAFD via mechanochemical leaching, solvent extraction, precipitation, and thermal decomposition route was investigated. Dissolution behavior of Zn, Fe, Mn, Si, Mg, and Ca during the mechanochemical leaching of EAFD in H2SO4 solution was determined. Optimum mechanochemical leaching parameters were considered as 10 g of EAFD, 2 M H2SO4, 240 min of reaction time, ball to the dust weight ratio of 20, and rotational speed of 500 rpm. D2EHPA solution (20%, vv) was used for solvent extraction of Zn from mechanochemical leach solution. McCabe–Thiele diagrams constructed for extraction and stripping stages indicated that 95% of zinc in the leach solution was extracted in three stages at A:O = 1:1, while 97% of Zn was stripped from loaded organic phase at operating line of A:O = 4:1. ZnC2O4∙2H2O powder was precipitated from strip solution obtained by solvent extraction by adding oxalic acid solution at pH 4. Thermal properties of ZnC2O4·2H2O precipitated were investigated by thermogravimetric–differential thermal analysis technique. High-purity ZnO was obtained by thermal decomposition of ZnC2O4∙2H2O precipitated.