“Geber's Method” in Environmental Perspective Revisited

Green and sustainable production of secondary products from waste sources is needed for a global circular economy. The primary aim of this work was to produce ferric ammonium sulfate (FAS) from acid mine drainage (AMD). AMD with a Fe content of approximately 240 mg/L was used as a matrix to model FAS formation under different solution concentrations of Fe and S (as ferric sulfate and sulfuric acid). This approach offered the benefit of identifying boundary conditions for FAS synthesis from wastes, so that the results of this study can be applied to many different AMD compositions. Results showed that increased Fe concentrations were associated with higher crystal yields and more selective crystallisation. Fe, S, and Al were more selectively incorporated over other elements present in AMD, however, XRD analysis did not show additional Al-bearing alum products. FAS was produced for AMD solutions where Fe was above 2500 mg/L, which demonstrates that FAS could be formed from iron-rich waste solutions.

Fine particles are those less than 10 microns in diameter and are often not detected as single particles by a light microscope. They have a very large relative surface area which tends to accelerate any reaction as well as increasing their ability to adsorb another substance. Flue-gas corrosion is caused by sulphur compounds and water vapor forming sulphuric acid which attacks iron to form ferric and ferrous sulphate. The former is a catalyst in the formation of sulphur trioxide from sulphur dioxide. Sulphur trioxide and ferric sulphate also raise the dew point. Fine particles consist of unburned fuel and ash spheres known as cenospheres or fragments of the latter. They increase the reaction rate as well as the condensation temperature and rate. They can attain a temperature lower than that of the gas stream by radiation and are good condensation nuclei. A qualitative test of the formation temperature, extent, and nature of deposits from cleaned and dirty gas showed that deposits tend to build up in a narrow range and that cleaning the gas greatly decreases the rate of deposit build-up.

This study investigates the leaching kinetics of chalcopyrite concentrate using three different lixiviants: sulfuric acid (H SO ), ferrous sulfate (FeSO ), and ferric sulfate (Fe (SO ) ) across a temperature range of 25C to 65C.Characterization of the chalcopyrite concentrate via X-ray fluorescence (XRF) revealed copper and iron as the dominant components at 32.88% and 27.82%, respectively, confirming economic viability for copper extraction.Xray diffraction (XRD) analysis identified a complex mineralogical assemblage including chalcopyrite (CuFeS ), bornite (Cu FeS ), chalcocite (Cu S), covellite (CuS), and various gangue minerals.Scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) confirmed stoichiometric composition and revealed smooth, angular particle morphology with minimal surface oxidation.Kinetic modeling using the Shrinking Core Model (SCM) demonstrated temperature-dependent mechanistic transitions.For H SO leaching, diffusion through the product layer dominated with correlation coefficients (R) ranging from 0.90 to 0.99 and activation energies between 51.2 to 79.8 kJ/mol.FeSO leaching exhibited chemical reaction control at elevated temperatures (55-65C) with R values reaching 0.98, while diffusion control prevailed at lower temperatures (25-45C).Fe (SO ) leaching showed the most pronounced mechanistic shift, with diffusion control dominating below 45C (R up to 0.9959) and chemical reaction control above 55C (R = 0.9815).Copper recovery increased substantially with temperature across all lixiviants, ranging from 6-10% at 25-45C to 15-22% at 55-65C after eight hours.The formation of passivating elemental sulfur layers at lower temperatures and their breakdown at elevated temperatures explain the observed mechanistic transitions.These findings provide critical insights for optimizing industrial hydrometallurgical copper extraction processes from chalcopyrite concentrates.

One method of industrial manufacture of red ferric pigments is based on the thermal decomposition of FeSO4⋅7H2O into α-Fe2O3(copperas red). The difficult reproducibility of the color quality of the final pigment is the main problem of this process. One of the factors that can influence the pigment color is contamination by some of the intermediates formed during the transformation process. The identification of two groups of intermediates is the basic result of an extensive laboratory investigation carried out using 57Fe Mossbauer spectroscopy and X-ray powder diffraction (XRD). The first group of intermediates includes sulfato-phases as FeSO4⋅H2O, FeSO4, Fe(OH)SO4, Fe2O(SO4)2, Fe2O(SO4)2⋅xH2O x∈(0,1), and Fe2(SO4)3. Thermally metastable polymorphs of iron(III) oxide, β-Fe2O3, γ-Fe2O3 and e-Fe2O3, represent the other group. Mossbauer characterization of all intermediate products is given. A significant influence of β-Fe2O3 on the pigment color was found.

NiCrMo-alloys are usually tested in a ferric sulfate-sulfuric acid solution according to ASTM G-28 to make sure that intergranular attack due to sensitization of grain boundaries will not occur. An attempt was made how, in this case, application of electrochemical techniques would allow a better under- standing of the test. Current density potential curves were established for various NiCrMo alloys with up to 22% chromium, 13 to 16% molybdenum, up to 3 % tungsten and up to 3% iron in 50% sulfuric acid, heated close to the boiling point and compared to composition and microstructure of the alloys. In addition, potentiostatic measurements in 50% sulfuric acid and at free corrosion potential in ferric sulfate - 50 % sulfuric acid were performed. Electrochemical testing can provide more reliable test conditions than the ASTM immersion test and shorter testing times might be possible. Whereas reliable testing of alloy C-276 for irregularities requires lower sulfuric acid concentrations than 50%, the alloy C-22 type of materials exhibits a sufficient degree of passivity. The TTS-diagram indicates sensitization after an anneal of 1 hr. in the 750-800° range. Sensitization makes passivation more difficult and increases the passive current mainly because of enlargement of the corroding surface. TIG welds show a more noble behaviour than the base metal. Substituting molybdenum for tungsten in the 22% chromium bearing alloys results in essentially the same electrochemical and corrosion behaviour in the test solution and in 50% sulfuric acid.

Preliminary field and laboratory observations have been made on the acidification of calcareous and artificially alkalized soils using aluminium sulphate, ferrous sulphate and sulphuric acid. In calcareous soils aluminium sulphate was much more effective than ferrous sulphate in giving persistent acidity; in neutral soil acidity from aluminium sulphate persists for a year but that produced by sulphuric acid is small and short‐lived. The effects of continuous irrigation of the soil are reported. The effects of the three acidifiers on manganese mobilization, phosphate fixation and solubilization are also recorded.

D a t a for the ternary system ferrous sulfatesulfuric acid-water a r e presented for Oo, 27O, 40°, 60°, and looo C. Such data a r e helpful in solving the problem of recovery and utilization of waste pickle liquor. E r r o r s in existing data for binary and ternary systems a r e a lso discussed. The steel industry has worked assiduously to solve the technical problem of recovery and utilization of waste pickle liquor. Numerous processes have been prcJposed (8, 10, 11, 13, 16,23,24). Many of these call for the separation by crystallization of ferrous sulfate in various hydrated forms from the waste solution. To have complete information for engineering calculations, data for the system ferrous sulfate-sulfuric acid-water should be available over the complete range of sulfuric acid concentrations and from Oo to looo C. This paper presents such solubility data. An enthalpy-concentration diagram for the system ferrous sulfate-water has previously been prepared (20). The amount of waste pickle liquor produced annually i s not known definitely, Hoak (12) estimates it to be in excess of 600 million gallons, and Hodge (14) estimates it from 500 to 800 million gallons. The concentrations vary with pickling processes; typical analyses a r e given by Hodge. In modern continuous s t r ip picklers a typical analysis would be 7% sulfuric acid, 15% ferrous sulfate, and 78% water. Bramer and Coull ( 5 ) estimate nearly a billion gallons of waste pickle liquor annually with an average composition of 5% sulfuric acid and 15% ferrous sulfate.

In recent years, recovering precious and base metals such as silver and copper from end-of-life products has become a fundamental factor in the sustainable development of many countries. This not only supports environmental goals but is also a profitable economic activity. Therefore, in this study, we investigate the recovery of silver and copper from an end-of-life photovoltaic panel powder using an alternative leaching system containing sulfuric acid and ferric sulfate instead of nitric acid-based leaching systems, which are susceptible to producing hazardous gases such as NOx. To obtain this goal, a series of experiments were designed with the Central Composite Design (CCD) approach using Response Surface Methodology (RSM) to evaluate the effect of reagent concentrations on the leaching rate. The leaching results showed that high recovery rates of silver (>85%) and copper (>96%) were achieved at room temperature using a solution containing only 0.2 M sulfuric acid and 0.15 M ferric sulfate. Analysis of variance was applied to the leaching data for silver and copper recovery, resulting in two statistical models that predict the leaching efficiency based on reagent concentrations. Results indicate that the models are statistically significant due to their high R2 (0.9988 and 0.9911 for Ag and Cu, respectively) and the low p-value of 0.0043 and 0.0003 for Ag and Cu, respectively. The models were optimized to maximize the dissolution of silver and copper using Design Expert software.

Due to the government pressure and public awareness, industries are bound to incorporate sustainability in their manufacturing process. In this context, the concept of lean manufacturing and value stream mapping (VSM) process has been used widely in various manufacturing industries to minimize the waste in their production process. The objective of this study is to propose a conceptual model for the integration of VSM tool integrated with various sustainability indicators. The proposed model is capable to assess the manufacturing process into three sustainability dimensions such as economic, social, and environmental. This methodology was applied to two different manufacturing industries such as automotive component manufacturing organization and PVC pipe manufacturing organization, situated in India. The result demonstrated that the proposed methodology identified the areas of improvement after applying these integrated methodologies and clearly enabled the opportunities for improvements in both manufacturing organizations.

The fluorescence quenching of calcein (CA) is not iron specific and results in a negative calibration curve. In the present study, deferoxamine (DFO), a strong iron chelator, was used to regenerate the fluorescence quenched by iron. Therefore, the differences in fluorescence reading of the same sample with or without addition of DFO are positively and specifically proportional to the amounts of iron. We found that the same iron species but different anions (e.g. ferric sulfate or ferric citrate) differed in CA fluorescence quenching, so did the same anions but different iron (e.g. ferrous or ferric sulfates). Excessive amounts of citrate competed with CA for iron and citrate could be removed by barium precipitation. After optimizing the experimental conditions, the sensitivity of the fluorescent CA assay is 0.02 microM of iron, at least 10 times more sensitive than the colorimetric assays. Sera from 6 healthy subjects were tested for low molecular weight (LMW) chelator bound iron in the filtrates of 10 kDa nominal molecular weight limit (NMWL). The LMW iron was marginally detectable in the normal sera. However, increased levels of LMW iron were obtained at higher transferrin (Tf) saturation (1.64-2.54 microM range at 80% Tf saturation, 2.77-3.15 microM range at 100% Tf saturation and 3.09-3.39 microM range at 120% Tf saturation). The application of the assay was further demonstrated in the filtrates of human liver HepG2 and human lung epithelial A549 cells treated with iron or iron-containing dusts.

Acid and ferric sulfate bioleaching of uranium ores: A review #

This paper proposes a new approach to synthesize polymeric ferric sulfate (PFC). It was found that the basicity and stability of the synthesized PFS varied with the quantity of sulfuric acid used. The minimum amount of sulfuric acid needed for the synthesis of PFS to insure a residual Fe\U2+\N concentration in the product lower than 0.1 wt% is about 31.0 wt% of the stoichiometric requirement. However, to produce a stable product which can be stored for six months, the amount of sulfuric acid should be 51.7 and 62.0 wt% of the stoichiometric requirement for PFS produced at 55 and 85°C, respectively. The structure of PFS depended on the synthesis temperature, as observed through x-ray diffraction and transmission electron microscopy. A comparison of the coagulation performance of PFS and ferric sulfate (FS) showed that PFS is, in general, more effective than FS in reducing the turbidity of Kaolinite suspensions for various conditions.

ABSTRACTIC218 contains about 8.4% aluminum and about 7.8% chromium by weight and forms a tenacious alumina scale. In this work the ability of the scale to protect against aqueous corrosion and abrasive and adhesive wear was evaluated. Wrought IC218 was heat treated at 1150°C, yielding a microstructure of ordered FCC islands in a disordered FCC matrix. This material was more resistant to corrosion than common stainless steels in 96% or 98% sulfuric acid and in 5% hydrochloric acid. It was approximately equivalent to stainless steels in 10% sulfuric acid, 50% acetic acid, 50% sodium hydroxide, 5% sodium chloride, and in a sodium chloride + ferric sulfate + hydrochloric acid mixture used to test for pitting resistance. The IC218 performed poorly in 45% sulfuric acid, 20% or 65% nitric acid, 20% phosphoric acid, and in electrolytic 10% oxalic acid. It did not exhibit sensitivity to intergranular corrosion. It resisted stress corrosion cracking at a stress level equal to its yield strength, 645 MPa, in 45% magnesium chloride and in NACE TM0177, a test that simulates an oil well environment. IC218 wore more quickly than austenitic stainless steels do in a dry-sand-rubber-wheel test, but resisted galling as well as or better than most of them do.

The manufacturing companies in this contemporary competitive global business environment are facing different kinds of challenges in manufacturing activities regarding improvement of the safety, quality, and efficiency of the entire manufacturing operation. In order to improve quality, safety, and efficiency of the manufacturing activities, the contemporary manufacturing firms are capitalising the advantages created by IoT because it enhances strong values for the organisations in their manufacturing activities. Manufacturing process of an organisation can be improved through effective quality control, enhanced inventory management, and significant predictive maintenance activities. Overall, use of IoT in the manufacturing process helps the contemporary manufacturing organisations across the globe to improve resource optimisation process in their manufacturing activities. Like these ways, IoT assists the organisations in monitoring and improving the manufacturing process in the global manufacturing industry. Relevant research objectives properly aligned with the research title are created. In addition, relevant theories and models are used in the literature review section to determine the effects of IoT in the efficacy management of manufacturing process. In order to meet the created objectives, qualitative research method is considered in this investigative study. Most importantly, secondary data analysis has been conducted to determine the efficacy of IoT in the manufacturing process of the organisations. In findings, challenges associated with the implication of IoT also have been determined. Based on the analysis and findings, some effective recommendations are suggested to overcome the possible challenges associated with the application of IoT in manufacturing activities.

Oxygen solubility in copper bioleaching solutions