Flame Spectrometry Research Articles

Chemical elements migration in underground waters of mining territory

Relevance. The need to study the forms of migration of chemical elements in the groundwater of flooded copper pyrite mines in order to correctly understand and predict their transfer and distribution in hydrogeochemical fields. Ground and surface waters are a complex mixture of substances in which, depending on pH, Eh and t °С, phase transitions are formed with subsequent dissolution or precipitation of minerals. To solve these problems, numerical hydrogeomigration modeling is used, including physicochemical, which allows drawing conclusions about the scale of pollution and the localization of such areas for subsequent development of measures to improve the state of the hydrosphere. Aim. To determine the forms of metal migration in groundwater and to calculate water saturation indices in relation to minerals. Objects. Groundwater in the territory of the closed Levikha copper pyrite mine. Methods. Laboratory studies of groundwater were carried out using flame emission spectrometry, flame atomic absorption, photometric method with Nessler's reagent, titrimetric, mercumetric and potentiometric methods; mass spectrometry with ionization in inductively coupled plasma and gravimetric method. Physical and chemical modeling using the software product Visual MINTEQ 3.1. Results. According to the results of processing chemical analyzes and physical and chemical modeling, all tested wells are divided into groups: 1) wells no. 1, 2, 3 and 6, located within the former mining allotment (near the Levikha XIV mine, a man-made reservoir, the Levikha II mine and a neutralization station); 2) represented by water in wells no. 4 near the shaft of the mine Tsentralnaya and no. 5 near the dump Yuzhny; 3) well no. 7, located near the mouth of the Levikha river. Saturation indices and forms of migration of components in the aquatic environment make it possible to identify the scale of pollution and the localization of such areas. Thus, with the current pumping system, there is no large-scale pollution of groundwater at the Levikha mine. It is localized in the area of the Tsentralny mine shaft (well no. 4) and the Yuzhny dump (well no. 5).

Portable X‐ray fluorescence spectrometry accurately measures metal concentrations in aqueous Mehlich III soil extraction solutions

AbstractAccurate measurement of metal concentrations in soil and water is vital for healthy crop production and decision making for environmental surveys. While there are a multitude of laboratory‐based soil analysis methods, such as inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), flame emission spectrometry, and atomic absorption spectroscopy, most are time and resource intensive. Additionally, there is a lack of information for rapid analysis of elements for aqueous soil extractions. The goal of this research is to establish elemental correlations between portable X‐ray fluorescence (pXRF) measurements of Mehlich III soil extractions and traditional elemental measurements via ICP‐OES. We hypothesize that certain metals can be accurately measured in aqueous soil extraction solutions by pXRF to the same degree as they are measured by ICP‐OES. To test this hypothesis, Mehlich III and 2% nitric acid solutions with known elemental concentrations were analyzed via ICP‐OES and pXRF. Soil samples extracted using Mehlich III were compared between ICP‐OES and pXRF to verify correlations. High correlations were found for As, Ca, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, V, and Zn in both the Mehlich III and 2% nitric acid solutions at concentrations between 5 and 85 mg L−1. P, S, and Si did not show high correlations at concentrations <100 mg L−1. These results indicate that between 5 and 85 mg L−1, pXRF analysis of aqueous solutions and soil extractions is a reliable technique; however, at low concentrations (i.e., <5 mg L−1 for metals and <100 mg L−1 for P and S), pXRF is not well suited.

Biomass flame spectroscopy technique to identify wood species through spectral emission during combustion processes

The energy emitted by a flame and its spectra provide critical information about fuels, such as energy type, temperature, and molecular properties. While traditionally used to analyze combustion, we introduce a spectral-time-based index, optical calorific power (OCP), to calculate the total energy released per mass unit (J/Kg), relating to the calorific value of wood-based fuels. Using novel optical variables and machine learning, we identified different wood species during the combustion of the wood samples. Homogeneous samples of four wood species (sapwood and heartwood) were ignited in a temperature-controlled furnace. Spectra were measured using a calibrated spectrophotometer in the 450–900 nm range with a 100ms integration time. Continuous and discontinuous spectral patterns were observed in all samples, used to calculate spectral-time-based optical variables, and separated using the AirPLS algorithm. Discontinuous spectra correlated with Na and K emissions (589.4 nm and 766.5 nm, respectively). Continuous spectra were analyzed to determine optical variables such as flame temperature (K), total continuous radiation (TCR, μW/cm2), and total continuous energy (TCE, μJ). Five supervised classification models, XGBoost, LR, SVM, LDA, and RF, were trained using normalized physical parameters and optical variables with stratified cross-validation. The proposed optical variables yielded an identification accuracy of 93%, precision of 95%, and recall of 93% during combustion using the XGBoost method. These promising results demonstrate the potential of our method for accurately identifying wood species, while offering a cost-effective and novel alternative to NIR-SWIR reflectance spectral identification techniques.

In-situ two-dimensional temperature measurements using x-ray fluorescence spectroscopy in laminar flames with high silica particle concentrations

X-ray fluorescence spectroscopy (XRF) was used to measure temperatures and study mixing, for the first time in silica particle synthesis flames. Hexamethyldisiloxane (HMDSO) and trimethylsilanol (TMSO) were the particle precursors. A multi-element diffusion burner was used to produce a flat methane flame, and the precursors, dilute in inert gas, were injected via a central jet. Krypton was the fluorescent medium at 3.2 % concentration by volume. Scans with Kr in the central flow and not in the main flow were made to assess the mixing effects between the central and main gas flows. When HMDSO or TMSO were added, a secondary diffusion flame formed between the jet and the main methane flame. The results revealed a dramatic change in the centerline temperature profile of the jet gases when HMDSO or TMSO were added. The main methane flame stoichiometry also affected the temperature profiles. The results show HMDSO and TMSO reactions are initiated in a low-temperature and low-oxygen concentration region of the jet where thermal decomposition is not expected to be significant. Reaction of the particle precursors is therefore attributed to radical transport from the main methane flame. In the current work, particle number densities of up to 270 g/m3 locally are estimated. Thus, the study also demonstrates the capability of the XRF technique for high spatial fidelity measurements in flames with high concentrations of condensed-phase particles, leveraging the attribute that the XRF signal is generally not impacted by condensed-phase interferences. The observations and data obtained in this study inform likely reaction pathways for this important class of siloxane compounds.

Nutritional Composition of Some Selected Commercial Juice Made in Nigeria

Introduction: Nutrient-fortified food play a crucial role in addressing nutritional deficiencies among infants and children, making them more appealing for consumption. Research focuses on baby foods, particularly reconstituted juice drink, which serve as significant sources of essential minerals and vitamins. However, the nutrient composition of these products varies, leading to differences in quality. The objective of this study is to assess the disparities in the nutritional content of various children's juice drink available in the Nigerian market. Methods: Proximate analysis was carried out according to the standard procedure of Association of Official Analytical Chemists (AOAC) to evaluate the nutritional composition of the selected juice drink. Minerals content were determined using Atomic Absorption and Flame Spectroscopy Techniques. The determination of the Vitamin A content in the samples was conducted following a modified Spectrophotometric Method. For Ascorbic Acid (Vitamin C), the Vitamin C content in the samples was assessed utilizing a Spectrometric Method coupled with 2,4 Dinitrophenyl hydrazine (DNPH) procedures. Results: Examination of the proximate and mineral analyses of ten chosen fruit juice brands revealed notable variations. Capri sonne exhibited the highest moisture content at 94.2%, while Hollandia Yogurt has the lowest at 81.3%. Chapman, Nutri Milk, and Viju Apple Flavor Milk shared the highest ash content at 0.5%, whereas Hollandia Malt, Piko Orange, and Piko Strawberry displayed the lowest at 0.01%. Nestle Malt boasted the highest crude protein concentration at 4.38%, with Capri sonne recorded the lowest at 0.18%. Hollandia Yogurt and Hollandia Malt demonstrated the highest crude fiber content, while Vitavite Multivi, Piko Orange, and Piko Strawberry showed the lowest. Regarding total carbohydrates, Hollandia Yogurt topped the list at 14.6%, while Vitavite Multivi ranked lowest at 6.57%. Nestle Millo contained the highest vitamin C content at 25.7%, whereas Piko Strawberry has the lowest at 3.82%. Caprosonne registered the highest vitamin A content at 0.6%. In terms of mineral analysis, Hollandia Yogurt exhibited the highest sodium percentage at 22.6mg/g, while Nestle led in calcium, iron, and magnesium content at 120.4mg/g, 1.7mg/g, and 25.5mg/g, respectively. It can therefore be inferred from the outcome of this study that, Milo Nestle is the best drink for children due to its higher protein, carbohydrate, vitamins (A and C) and minerals (Ca, Mg, Fe, Na) contents, followed by Hollandia Malt as compared to other juice studied.

In-situ measurement of potassium and sodium concentrations in a 16 MW MSW incinerator employing the FES system

To comprehensively understand the release characteristics of alkali metals which can cause corrosion and slagging problems in municipal solid waste (MSW) incinerators, the temporal concentrations of sodium (Na) and potassium (K) in a 16 MW MSW incinerator were measured employing a calibrated flame emission spectroscopy (FES) system. The experimental results revealed that the concentrations of alkali metals increased first and then decreased from the left side to the right side of the MSW incinerator. The maximum concentrations of Na and K were 111 ppm and 184 ppm, respectively. The peak and average concentrations of K near the left wall were 27 % and 58 % higher than those near the right wall at the same height of the MSW incinerator, owing to the different combustion stages of the MSW. The differences of the peak and average concentrations of K at the different heights of the MSW incinerator were 33.7 % and 23.5 %, respectively. Moreover, a positive correlation between the concentration of alkali metals and flame temperature was confirmed during the char phase combustion stage. Since the primary air distribution pattern of MSW incinerator decreased form the left side to the right side, the concentration of alkali metals near the left wall was positively correlated with the primary air flow, and that near the right wall exhibited a positive correlation with the garbage caloric value. This research provided an effectual solution for in-situ measurement of alkali metal concentration and flame temperature in MSW incinerators.

The Influence of Voltage on Gliding Arc Discharge Characteristics, the Composition of Air Plasma, and the Properties of BG-11 Medium

A gliding arc discharge (GAD) plasma device has been developed and tested. Possible applications areas for GAD plasma could be microalgae suspension treatments and the creation of plasma-activated water. To understand its behavior, the influence of the input power on the electrical characteristics of the generated GAD plasma was investigated using an oscilloscope. The waveforms of the voltage and current of GAD plasma are presented. The duration of the discharge time and the evolution of the arc during discharge were determined and investigated. It was revealed that the increase in the output voltage prolonged the duration of the arc discharge. The composition of the air plasma was investigated using a flame-emission spectrometer and acousto-optic emission spectrometer. It was revealed that the main species in the emission spectra of the GAD air plasma were N2, N2+, N+, NO, and O species. Furthermore, the increase in the input power enhanced the ionization degree of the air plasma and increased the intensities of the emission lines associated with N2+, NO, and O species. An increase in the conductivity of the BG-11 medium was observed. Physicochemical analyses of the plasma-activated BG-11 medium indicated an increase in the concentration of nitrite and nitrate ions and hydrogen peroxide with an enhancement of the voltage.

In vitro Assessment of Antimicrobial potential of Siddha Polyherbal Formulation Tulasi oil against RTI pathogens

In Siddha medication, along with herbal formulations, some mineral formulations are used clinically to prevent or cure infectious diseases. The therapeutic values of some siddha formulations have been well documented earlier, but a huge number of them remain unexplored in terms of safety and efficacy. The aim of this study was to screen the antimicrobial potential of Siddha polyherbal formulation Tulasi oil (SPHTO) against respiratory tract infection (RTI) causing pathogens. The antimicrobial activity of SPHTO was examined by using the methods of agar well diffusion, Minimum inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC), Minimum Fungicidal Concentration (MFC) and Microbicidal action. Ciprofloxacin (bacteria) and Amphotericin B (fungi) were used as the positive control for this study. The potassium leakage was determined using a flame emission and atomic absorption spectroscopy. All tested concentrations gave notable antimicrobial activity against all tested pathogens. The 100mg/ml concentration showed the highest activity against E.coli followed by 200mg/ml against K. pnuemonia and C.neoformans when compared to 50 and 25mg/ml. For MIC, the highest activity was registered at 150mg/ml concentration against E. coli, while MBC/MFC was 200mg/ml concentration has shown the better activity against K. pneumonia and C. neoformans. Tulasi oil induced leakage of potassium ions from cells of E.coli and K.pneumonia suspended in glycil-glycine buffer solution and the leakage started within 10 minutes of contact of drugs with target cells. From this study, it may support the clinical claims of Tulasi oil to have potent antibacterial and antifungal activities and offer profound therapeutic benefits against respiratory tract infection.

Study of the Physicochemical, Nutritional and Microbiological Quality of Toedo Candies Produced in Ouagadougou, Burkina Faso

In Burkina Faso, the pulp of the baobab tree (Adansonia digitata) is mainly used to produce fruit juices or candies called toedo candies. Teodo candies are produced and sold in the markets and popular with the people. However, there is little data on the physicochemical, nutritional and microbiological characteristics of teodo candies produced in Ouagadougou. Thus, this study aimed to evaluate the physicochemical, nutritional and microbiological characteristics of these teodo candies. To carry out the study, 9 samples of toedo candy were taken from different producers in the city of Ouagadougou. The physicochemical and microbiological characteristics were determined by standard methods. Mineral contents were determined by flame spectrometry. The results obtained show that the toedo candies have an average ash content of 1.3±0.21 to 1.9±0.06%, a titratable acidity of 0.131±0.001 to 0.168±0.002%, a pH varying from 3.87±0.10 to 3.91±0.10, a water content from 3.84±0.00 to 16.06±0.14% and a dry matter (DM) content of 84.04±0.14 to 96.16±0.00%. In addition, this study revelead that these samples are rich in micronutrients such as : iron (49.30 to 127.50 mg/100 g DM), magnesium (3.53 to 42.38 mg/100 g DM), zinc (1.37 to 14.92 mg/100 g DM) and calcium (17.60 to 43.30 mg/100 g DM). Microbiological analyzes indicate the presence of total mesophilic aerobic flora (TMAF), yeasts and molds (YM) and coliforms in the samples analyzed with loads of 2.2x103 to 4.9x104 CFU/g, ˂10 to 2.0x102 CFU/g and ˂10 to 5.0x102 CFU/g respectively. For all the germs studied, 11.11% of the samples were of unsatisfactory quality, 44.44% of acceptable quality and 44.44% of satisfactory quality.

Coaxial burner system for solid-sample flame emission spectroscopy.

We present a burner system to analyze solid, inflammable samples by flame emission spectroscopy without requiring any sample preparation procedures. An acetylene-nitrous oxide burner was designed to efficiently introduce solid particles into the flame through active injection, enabling real-time elemental analysis. Computational fluid dynamics (CFD) simulations were employed to study particle transport dynamics within the burner system. The emission was characterized through spectral analysis of the flame emission from copper- and iron-metal powder mixtures, demonstrating its ability to determine elemental compositions without prior sample treatment. An artificial neural network (ANN) was implemented to analyze spectral data obtained from binary Cu/Fe metal mixtures, enabling rapid and reliable identification of constituent elements with an uncertainty of σ = 2.7 mol%. The blackbody temperature could be determined in the range of 2200-2600 K with an accuracy of 7 K.

Flame emission spectroscopy of single droplet micro explosions.

Nanoparticles exhibit superior physical and chemical properties, making them highly desirable for various applications. Flame spray pyrolysis (FSP) is a versatile technique for synthesizing size and composition-controlled metal oxide/sulfide nanoparticles through a gas-phase reaction. To understand the fundamental mechanisms governing nanoparticle formation in FSP, simplified single-droplet experiments have proven to unravel the physicochemical mechanisms of liquid metal precursor combustions. This work introduces a novel method using flame emission spectroscopy and high-speed imaging to analyze combustion species and metal release during metalorganic single droplet combustions, with the example of the 2-ethylhexanoci acid (EHA)-tetrahydrothiophene (THT)-mesitylcopper (MiCu) precursor system. The method enables the tracing of precursor components released from droplet into the flame by spatial and temporal resolved emission tracking from combustion species (OH*, CH*, C2*, CS*, CS2*) and atomic spectral lines (Cu I). The tracking of metal emission enables the direct observation of the particle formation route, offering novel insights into the metalorganic precursor combustions. The findings of this work show a direct correlation between micro-explosions and nanoparticle formation through the gas-to-particle route. The release of copper emissions is observed with the micro-explosion event, marking the micro-explosions as the critical mechanism for the metal release and subsequent nanoparticle formation during the combustion process. The results indicate a metalorganic viscous shell formation (THT + MiCu) leading to the micro explosion. The EHA/THT ratio significantly affects the combustion behavior. Lower ratios lead to a gradual copper release before the micro explosion; higher ratios shorten the copper release and delay the micro explosion - the highest ratio results in two distinct burning stages.

(Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation) Aqueous Batteries for Grid-Scale Storage: Beyond Highly Concentrated Electrolytes

Aqueous electrolytes offer significant advantages over their organic counterparts, particularly for large-scale applications that prioritize non-flammability, scalability, and sustainability. However, the narrow electrochemical stability window of water imposes voltage limitations, resulting in low energy densities of aqueous batteries. Highly concentrated electrolytes have enabled high-voltage, mostly intercalation-type, aqueous battery chemistries, and over the past decade many additives, coatings, and highly soluble salts have been developed to manipulate the solution structure of the electrolyte and the interphasial chemistry at the electrode surfaces. However, the large amounts of specialized salts required in this approach, put into question whether GWh-scale storage is really the best application of this technology.Storage at such very large scale, however, is required for further integration of renewables and complete decarbonization of power grids. Flow batteries that decouple energy storage from power generation were developed to simplify scaling of very large batteries while maintaining cost and safety benefits of aqueous electrolytes. Here, the solubility of active materials governs the achievable energy density, which is typically an order of magnitude lower for aqueous flow batteries compared to state-of-the-art lithium-ion cells.Capitalizing on our experience with highly concentrated electrolytes and the impact of molecular symmetry and ion-pairing on electrolyte properties,1–5 we manipulate the solution structure of flow battery electrolytes to maximize active material concentration. We manipulate the hydrogen-bonding environment in the electrolyte and mediate anion-cation interactions via cation-engineering and additives, enabling more than four-fold higher concentrations for a series of metal-organic chelates and ferrocyanides than previously reported.6–8 We further developed a simple flame emission spectroscopy setup to track cation ratios in solution and study cation-dependent instabilities of presumably highly stable ferrocyanide anions.8,9 Achieving very high concentrations, however, presents a series of challenges for flow batteries. A two-molar lithium ferrocyanide electrolyte, for example, has an ionic strength comparable to a twenty-molar lithium chloride solution.8 Managing osmotic balance across the membrane thus becomes very challenging in a flow cell. Additionally, the high viscosity of concentrated electrolytes results in significant efficiency and power losses, suggesting that the “dissolve-as-much-as-possible” approach may not necessarily lead to better flow batteries.We thus studied the importance of energy density for real-world MWh-scale batteries by using satellite images to estimate the footprint of such large-scale deployments. We find that installations using lithium-ion batteries often have a comparable footprint to sodium-sulfur batteries and even demonstrator-stage flow batteries.10 This implies that low cell level energy density of flow batteries is not the key limitation of the technology, challenging the common narrative. For applications such as residential use, on the other hand, energy density certainly plays a critical role, and we discuss approaches that could enable much more compact systems.

Effect of Kaolin Addition on Combustion Behavior of Zhundong Coal Pellet Using Flame Emission Spectroscopy

ABSTRACT Kaolin, as an adsorbent, has been proven to be effective in inhibiting sodium release during high alkali coal combustion thereby alleviating severe slagging and fouling problems. Understanding the co-firing behavior of Zhundong coal with kaolin additives is essential for Zhundong coal utilization. In this study, the effect of kaolin additive on the combustion behavior of two Zhundong coals with different Na contents was investigated based on image analysis and flame emission spectroscopy (FES) method. Spectral and image results were able to distinguish the three stages of coal combustion. The addition of kaolin impacted all combustion stages for both types of coal. The results show the volatile combustion time of the blended coal sample was shortened, while the char burnout time was prolonged, which was attributed to the ash suppression effect. The two coals presented similar decrease trends with different blending ratios in terms of sodium concentration, pellet surface temperature, and thermal radiation. However, the changes were no longer evident after the blending ratio reached 8% and 12%. The replacement of combustible components in the coal by the kaolin altered the mineral fraction of the ash and thus affected the heat and mass transfer. Combining the online measurement results and the analysis of the ash fusion characteristics, the suggested addition of kaolin was 8% and 12% respectively.

In vitro techniques for evaluating smear layer removal by root canal irrigants: a literature review

Introduction: The purpose of this review is to address the most commonly used techniques for evaluating smear layer removal ability or chelating capacity of root canal irrigants, including Energy Dispersive X-Ray Spectroscopy (EDS or EDX), Atomic Absorption Flame Spectrometry (AASF), wavelength dispersive X-ray fluorescence spectrometry (WDXRF), inductive coupled plasma emission spectroscopy (ICP-AES), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). Methods: An electronic literature search was conducted in the Pub Med / MEDLINE database of indexed journals from 1992 to 2020. The search terms included chelating, chelation, calcium chelation, smear layer, smear layer removal, and demineralizing effect. Results: All the techniques were classified in terms of their results, both quantitatively and qualitatively. Even though smear layer removal and chelating capacity are not the same parameters, most of the studies included both techniques to correlate their results. SEM is the most commonly used technique for evaluating smear layer removal using various root canal irrigants. Ethylenediaminetetraacetic acid (EDTA) (17%) was the most widely studied root canal irrigant. Conclusion: Different techniques can be used to evaluate smear layer removal and chelating capacity of root canal irrigants. All of these methods have their corresponding advantages and disadvantages. This study aimed to provide researchers with a background for the selection of technique(s) to study the irrigant´s capacity for calcium chelation, which is applicable to smear layer removal.

Fence-Line Spectroscopic Measurements Suggest Carry-Over of Salt-Laden Aerosols into Flare Systems Is Common.

Pollutant emissions from gas flares in the upstream oil and gas (UOG) industry can be exacerbated by aerosols of coproduced liquid hydrocarbons and formation water that survive separation and enter the flare. Of noteworthy concern is the potential impact of salt-laden aerosols, since the associated chlorine may adversely affect combustion and emissions. Here, we use a novel approach to remotely detect carry-over of salt-laden aerosols into field-operational flares via flame emission spectroscopy targeting two of the most abundant species in produced water samples, sodium and potassium. Ninety-five UOG flares were examined during field campaigns in the Bakken (U.S.A. and Canada) and Amazon (Ecuador) basins. For the first time, carry-over of salt species into flares is definitively detected and further found to be concerningly common, with 74% of studied flares having detectable sodium and/or potassium signatures. Additional analysis reveals that carry-over strongly correlates with reported flared gas volume (positive) and well age (negative), but carry-over was also observed in flares linked to older wells and those flaring relatively little gas. Given the scale of global UOG flaring and the risk of salt-laden aerosols affecting emissions, these findings emphasize the need to review separation standards and re-evaluate pollutant emissions from flares experiencing carry-over.

REHABILITATION OF MAN-MADE FORMATION OF ABANDONED COPPER PYRITE DEPOSITS ON THE EXAMPLE OF LEVIKHINSKY MINE (MIDDLE URALS)

Link for citation: Rybnikova L.S., Rybnikov P.A., Navolokina V.Y. Rehabilitation of man-made formation of abandoned copper pyrite deposits on the example of Levikhinsky mine (Middle Urals). Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 137-150. In Rus. The relevance of the research is related to the need to rehabilitate of abandoned copper pyrite deposits affected by acid mine waters and justify measures to clean up the existing clarification pond. The main aim is to study the sludge composition and justify the measures to reduce the environmental load on the hydrosphere. Objects: clarification pond and neutralization sludge of the Levikhinsky copper pyrite mine acid mine waters. Methods. Laboratory studies of water and bottom sediments were carried out using atomic emission and mass spectral analysis; methods of flame emission spectrometry, flame atomic absorption, photometric method with Nessler's reagent, titrimetric, mercumetric and potentiometric methods; mass spectrometry with ionization in inductively coupled plasma and gravimetric method. Results. Sludge samples are dominated by sulfates (gypsum and bassanite), iron oxides and hydroxides (goethite), carbonates (calcite), clay minerals (mainly hydromica) and chlorine-containing salts (carnallite). The chemical composition of the sludge is dominated by oxides of iron, sulfur and calcium. The analysis of water and acid extracts showed that up to 24 elements belonging to hazard classes 2, 3 and 4 can be leached from the sludge in concentrations exceeding the maximum allowable values for fishery water bodies. Several options for the use of sludge from the clarification pond were analyzed: reclamation of waste rock dumps and substandard ores; backfilling of mined-out area of quarries; production of building materials; extraction of components; storage of sludge in geotubes (Geotube). The most rational is the disposal of sludge as the production of building materials on the basis of a public-private partnership, the implementation of which will allow the state and the private sector to derive mutual benefit.

Nutritional and economic value of local poultry feeds, formulated by design of experimental (DOE) method

A prospective study was conducted on feeds for local poultry in Burkina Faso. The objective of this study was to contribute to the improvement of the nutritional and economic quality of feeds for local poultry. Design of experimental (DOE) method was used to formulate ten feeds with mainly local raw materials and an evaluation of their nutritional and economic value has been carried out. Classical analytical methods were used to determine the macro elements. Chromatography and flame spectrometry were used to determine amino acids and minerals respectively. The results showed mass proportions (g/100 g DM) between 18.32±0.06 and 20.46±0.00 for proteins, 4.86±0.10 and 5.70±0.03 for lipids, 36.81±0.07 and 40.36±0.04 for total carbohydrates, between 10.28±0.09 and 12.34±0.12 for ash, between 7.03±0.09 and 7.79±0.00 for cellulose, 1.67±0.74 and 3.86±0.06 for calcium, 1.16±0.07 and 2.10±0.04 for phosphorus. Methionine contents ranged from 0.36±0.04 to 0.47±0.02, lysine from 0.78±0.07 to 0.94±0.00, and threonine from 0.68±0.02 to 0.83±0.03. The rations cost varied from 203.40 to 238.98 FCFA/kg with an average value of 213.77 FCFA/kg. The results obtained constitute new information in the breeding of local chicken in Burkina Faso. They will allow poultry farmers to make their activity more profitable.

Flame emission spectroscopy analysis of distributed liquid fuel combustion

Distributed combustion offers ultra-low pollutant emission, low susceptibility of thermoacoustic instabilities, and is highly fuel flexible, being an ideal choice for, e.g., boilers, furnaces, and gas turbines. It was recently demonstrated that Mixture Temperature-Control could also achieve distributed combustion and not restricted to Moderate or Intense, Low-oxygen Dilution combustion. The former approach is employed in the present paper. Online flame control is required by the need for dynamic operation, which is often performed via spectral flame measurements. Presently, the distribution of OH*, CH*, C2*, O2*, and two H2O* chemiluminescent emission peaks were evaluated; the first two represent ignition, while the latter four appear later in the reaction zone. Characteristics of distributed flames are compared to those of straight and V-shaped flames, which are well-known in the literature. The following observations were made. Distributed combustion is lifted and occupies the entire cross-section of the combustion chamber without featuring a characteristic shape. The OH*/CH* ratio shows a low dependence on the equivalence ratio, and the reactions start only 50 mm downstream of the burner lip. The dominant radical was CH* for all distributed flames. As the equivalence ratio increases, the reaction zone moves slightly upstream.

Spectroscopic characterisation of feedstock for copper smelters by machine-learning

ABSTRACT A flame-emission spectrometer was built to determine the elemental composition of powdered minerals that are important in copper smelting processes. The feedstock, consisting of milled concentrate, was fed into an oxyacetylene flame without sample preparation. The elemental composition (Cu, Fe, S, Si, and Zn) was determined by applying an artificial neural network (ANN) to a set of emission spectra obtained from Cu and Fe pure elemental powders, five pure mineral powders of known composition and 30 binary mixtures of these mineral samples. The ANN model was able to accurately predict the Cu and Fe content of these mineral powders within better than 2% of the value obtained from ICP-OES. The analysis was repeated on 12 industrial samples with well-known compositions. Spectra from these samples were analyzed both in isolation of the reference minerals and together with the reference minerals, giving similar results.

Alkaline gases emission estimation and paraconsistent logic techniques application to label bagasse combustion conditions

When some renewable energy sources are used, such as biomass solid waste, it is necessary to measure and control pollutant emissions. Since raw sugarcane comes from a wide variety of supply sources, it is necessary to monitor the behavior of the biomass residues during the burning process to control flame stability, emissions, and combustion efficiency. The variation in the combustion temperature of biomass affects the combustion efficiency and also the emission of alkaline metals, such as potassium (K) and sodium (Na), which can cause corrosion in boilers. The objective of the present work is to estimate the content of alkali gases in the flames during the burning of solid biomass residues, specifically sugarcane bagasse in this case. The flame emission spectroscopy (FES) spectrometry technique is used and flame emission spectra is captured during the combustion of bagasse in a pilot furnace. The flame temperature is calculated using the two-color method together with the inverse Levenberg-Marquard method. Models and correlations from literature are used to obtain a database of emission content of sodium and potassium. Using paraconsistent logic techniques, a predictor algorithm is implemented and bagasse samples were labeled to identify similar physical combustion conditions. The results of the emission of sodium and potassium estimated for groups labeled using the algorithm of paraconsistent logic are compared and show good agreement between them. A good and reasonable agreement was found in the estimation of the emission content of potassium and sodium.