scholarly journals Ammoniacal System Mechanisms for Leaching Copper from Converter Slag

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 712
Author(s):  
Alvaro Aracena ◽  
Andrés Valencia ◽  
Oscar Jerez
Keyword(s):  
Particle Size ◽  
Converter Slag ◽  
Research Work ◽  
Ammonium Hydroxide ◽  
Copper Extraction ◽  
Solution Ph ◽  
Intraparticle Diffusion Model ◽  
Electron Microscopy Analysis ◽  
Leaching Solution ◽  
Conversion Stage

In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution pH, agitation, temperature, NH4OH concentration and particle size. Results showed that the hydronium ion resulting from ammonium hydroxide dissociation was the main oxidant of copper compounds in slag, such as CuO, Cu2O and Cu, with the exception of CuFeO2. The particles contain a large amount of microcracks (porosity) in their refractory structure (analyzed by compositional image capture (BSE)). Thus, the diffusion of the leaching solution through the microcracks making contact with the copper oxides would be allowed. Leaching mechanisms were corroborated by X-ray diffraction and scanning electron microscopy analysis. Increasing temperature and NH4OH concentration while decreasing particle size obtained higher copper recoveries, reaching values of 84.8%. Under the same conditions, the main impurity (iron) was minimal (<2%). Solution pH also affected slag leaching. Agitation of the solution positively affected the rate of copper extraction. Leaching kinetics of the leaching solution through the porosity formed in the slag was analyzed under the intraparticle diffusion model. The reaction order was 1.2 with respect to the concentration of ammonium hydroxide and the model was inversely proportional to the square of the particle radius. The activation energy obtained was 42.3 kJ/mol for temperature range 283 to 333 K.

scholarly journals Leach-SX-EW copper revalorization from overburden of abandoned copper mine Cerovo, Eastern Serbia

2009 ◽  
Vol 45 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Z. Stevanovic ◽  
M. Antonijevic ◽  
R. Jonovic ◽  
Lj. Avramovic ◽  
R. Markovic ◽  
...  
Keyword(s):  
Ph Value ◽  
Cathode Current Density ◽  
Copper Recovery ◽  
Open Pit ◽  
Copper Extraction ◽  
Leaching Tests ◽  
Solution Ph ◽  
Mine Waters ◽  
Leaching Solution ◽  
Cathode Current

Hydrometallurgical processes for copper revalorization from overburden of abandoned mine Cerovo in Eastern Serbia were studied. Paper contain results of percolation leaching tests, performed with acidic mine waters accumulated in the bottom of the former open pit, followed by solvent extraction (SX) and electrowinning (EW) processes on achieved copper pregnant leach solutions. Usage of accumulated waste waters was objected to minimizing the environmental hazard due to uncontrolled leaking of these waters in nearby creeks and rivers. Chemical composition of acidic mine waters used for leaching tests was: (g/dm3): Cu - 0.201; Fe - 0.095; Mn - 0.041; Zn - 0.026; Ni - 0.0004; pH value - 3.3. Copper content in overburden sample used for leaching tests was 0.21% from which 64% were oxide copper minerals. In scope of leaching tests were examined influence of leaching solution pH values and iron (III) concentration on copper recovery. It was established that for 120 hours of leaching on pH=1.5 without oxidant agents, copper concentration in pregnant leach solutions enriched up to 1.08g/dm3 which was enough for copper extraction from solution with SX-EW treatment. As extraction reagent in SX circuit was used LIX-984N in a kerosene diluent. Cathode current density in electrowinning cell was 220Am-2 while electrolyte temperature was kept on 50?2oC. Produced cathode copper at the end of SX-EW process has purity of 99.95% Cu.

Development and Validation of Stability Indicating HPLC Method for the Determination of Impurities in the Sterile Mixture of Cefoperazone and Sulbactam

2019 ◽  
Vol 15 (7) ◽  
pp. 762-775
Author(s):  
Ramu Ivaturi ◽  
Thuttagunta Manikya Sastry ◽  
Satyaveni Sunkara
Keyword(s):  
Quantitative Estimation ◽  
Ammonium Hydroxide ◽  
Hplc Method ◽  
Forced Degradation ◽  
Buffer Solution ◽  
Solution Ph ◽  
Pharmaceutical Dosage Forms ◽  
Stability Indicating ◽  
Validation Parameters ◽  
Abdominal Infections

Background: Cefoperazone Sulbactam injection is a cephalosporin antibiotic with a β- lactamase inhibitor used in the treatment for intra abdominal infections, Urinary track infections, surgical infections, etc. The combination is not official in any of the pharmacopeia for their content and impurities determination. Introduction: The present study involves the development of a simple, rapid, accurate, sensitive and stability indicating RP-HPLC method for the quantitative estimation of Cefoperazone Sulbactam mixture and its impurities in bulk and pharmaceutical dosage forms. Methods: 0.005 M Tetrabutyl ammonium hydroxide buffer solution pH adjusted to 6.80 and Acetonitrile combination has been used in a gradient programme with a flow rate of 1.0 ml/min. The retention time of Cefoperazone and Sulbactam were observed at around 8.5 and 19.5 minutes respectively. The UV detection was carried out at a wavelength of 230 nm. The chromatographic separation was achieved using Waters xbridge C18-150*4.6 mm, 3.5 µm HPLC column. The method has been validated according to the current International Council for Harmonization (ICH) guidelines for the method validation parameters such as Specificity, linearity, range, accuracy, precision, robustness and sensitivity. Results: The validation results indicate that the method is specific, as the known impurities and other impurities formed during the forced degradation studies were not co-eluting with the main components. Moreover, all these impurities were found to be spectrally pure, proving the stability indicating power of the method. The linearity and range of the method is in the range of 0.01-150%, highly accurate (100.2%), precise (<1%) and robust. Conclusion: The proposed method was accurate and specific for the quantitative analysis of Cefoperazone and Sulbactam and their related impurities in the sterile mixture. Hence the proposed method can be used for the quantification of impurities in routine as well as stability analysis in the development as well as quality control laboratories.

Design and Evaluation of Long Acting Biodegradable PLGA Microspheres for Ocular Drug Delivery

2019 ◽  
Vol 10 ◽  
Author(s):  
Anjali Pandya ◽  
Rajani Athawale ◽  
Durga Puro ◽  
Geeta Bhagwat
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Degradation Products ◽  
Ex Vivo ◽  
Research Work ◽  
Entrapment Efficiency ◽  
Rational Approach ◽  
Plga Microspheres ◽  
Long Acting

Background: The research work involves development of PLGA biodegradable microspheres loaded with dexamethasome for intraocular delivery. Objective: To design and evaluate long acting PLGA microspheres for ocular delivery of dexamethasone. Method: Present formulation involves the development of long acting dexamethasone loaded microspheres composed of a biodegradable controlled release polymer, Poly(D, L- lactide-co-glycolide) (PLGA), for the treatment of posterior segment eye disorders intravitreally. PLGA with monomer ratio of 50:50 of lactic acid to glycolic acid was used to achieve a drug release up to 45 days. Quality by Design approach was utilized for designing the experiments. Single emulsion solvent evaporation technique along with high pressure homogenization was used to facilitate formation of microspheres. Results: Particle size evaluation, drug content and drug entrapment efficiency were determined for the microspheres. Particle size and morphology was observed using Field Emission Gun-Scanning Electron Microscopy (FEG-SEM) and microspheres were in the size range of 1-5 μm. Assessment of drug release was done using in vitro studies and transretinal permeation was observed by ex vivo studies using goat retinal tissues. Conclusion: Considering the dire need for prolonged therapeutic effect in diseases of the posterior eye, an intravitreal long acting formulation was designed. Use of biodegradable polymer with biocompatible degradation products was a rational approach to achieve this aim. Outcome from present research shows that developed microspheres would provide a long acting drug profile and reduce the frequency of administration thereby improving patient compliance.

scholarly journals Chitosan Nanocarrier Entrapping Hydrophilic Drugs as Advanced Polymeric System for Dual Pharmaceutical and Cosmeceutical Application: A Comprehensive Analysis Using Box-Behnken Design

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 677
Author(s):  
Sara A. Abosabaa ◽  
Aliaa N. ElMeshad ◽  
Mona G. Arafa
Keyword(s):  
Particle Size ◽  
Sodium Tripolyphosphate ◽  
Chitosan Nanoparticles ◽  
Optimization Procedure ◽  
Entrapment Efficiency ◽  
Chitosan Solution ◽  
Polydispersity Index ◽  
Successful Implementation ◽  
Solution Ph ◽  
Box Behnken Design

The objective of the present research is to propose chitosan as a nanocarrier for caffeine—a commonly used drug in combating cellulite. Being a hydrophilic drug, caffeine suffers from insufficient topical penetration upon application on the skin. Chitosan nanoparticles loaded with caffeine were prepared via the ionic gelation technique and optimized according to a Box–Behnken design. The effect of (A) chitosan concentration, (B) chitosan solution pH, and (C) chitosan to sodium tripolyphosphate mass ratio on (Y1) entrapment efficiency percent, (Y2) particle size, (Y3) polydispersity index, and (Y4) zeta potential were studied. Subsequently, the desired constraints on responses were applied, and validation of the optimization procedure was confirmed by the parameters exhibited by the optimal formulation. A caffeine entrapment efficiency percent of 17.25 ± 1.48%, a particle size of 173.03 ± 4.32 nm, a polydispersity index of 0.278 ± 0.01, and a surface charge of 41.7 ± 3.0 mV were attained. Microscopical evaluation using transmission electron microscope revealed a typical spherical nature of the nanoparticles arranged in a network with a further confirmation of the formation of particles in the nano range. The results proved the successful implementation of the Box–Behnken design for optimization of chitosan-based nanoparticles in the field of advanced polymeric systems for pharmaceutical and cosmeceutical applications.

scholarly journals Effects of Fe+2 and Fe+3 in Pretreatment and Leaching on a Mixed Copper Ore in Chloride Media

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 866
Author(s):  
María E. Taboada ◽  
Pía C. Hernández ◽  
Aldo P. Padilla ◽  
Nathalie E. Jamett ◽  
Teófilo A. Graber
Keyword(s):  
Chloride Concentration ◽  
Solution Concentration ◽  
Copper Extraction ◽  
Curing Time ◽  
Ferrous Ions ◽  
Copper Ore ◽  
Second Stage ◽  
Acid Consumption ◽  
Nacl Concentration ◽  
Leaching Solution

A study of the pretreatment stage and subsequent leaching of a mixed copper ore with different chloride solutions containing iron was carried out. The first stage considered pretreatment tests to decide the best conditions. Two levels of each factor were analyzed, 20 and 50 kg/t of NaCl, 17 and 25 kg/t of H2SO4, 0 and 25 kg/t of Fe2(SO4)3·9.2H2O, 0 and 25 kg/t of Fe2SO4·7H2O, and a curing time of 15 and 30 days. The results showed a significant effect of NaCl and curing time on the extraction, and less effect was found with the variation of acid and iron salts. The second stage included column leaching using a solution with 0.5 g/L of Cu+2, 80 g/L of Cl−, 10 g/L of H2SO4, and variable concentrations of ferric and ferrous ions (0 and 2 g/L). The best copper extraction of 80.2% was found considering a pretreatment of 30 days, 25 kg/t of H2SO4, 50 kg/t of NaCl, and a leaching solution concentration described previously with 2 g/L of Fe+2. The results showed the leaching of all copper oxide species and 20% of the copper sulfide species. In addition, there was a reduction in the acid consumption as the resting time increases. Furthermore, to evaluate a possible decrease in time and acid in pretreatment and chloride in leaching, tests including 10 and 25 kg/t of H2SO4 and 1, 15, and 30 days of curing and a diminution of the NaCl concentration to 20 g/L (content from seawater) were executed. The results showed a significant effect on curing time below 15 days. Furthermore, the slight influence of the decrease of acid on copper extraction gives cost reduction opportunities. The diminution of chloride concentration (80 to 20 g/L) in leaching solution decreases the extraction from 79% to 66.5%. Finally, the Mellado leaching kinetic model was successfully implemented.

scholarly journals Study on Adsorption of Cu and Ba from Aqueous Solutions Using Nanoparticles of Origanum (OR) and Lavandula (LV)

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ghadah M. Al-Senani ◽  
Foziah F. Al-Fawzan
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Free Energy ◽  
Aqueous Solutions ◽  
Thermodynamic Parameters ◽  
Solution Ph ◽  
Environment Friendly ◽  
Removal Of Heavy Metals ◽  
Equilibrium Data ◽  
Langmuir And Freundlich Models

Wild herbs (Origanum (OR) and Lavandula (LV)) were used as environment-friendly adsorbents in this study. The adsorbents were used for adsorption of Cu and Ba from water. The adsorption of heavy metals onto OR and LV was dependent on particle size, dose, and solution pH. The diameter of adsorbent particles was less than 282.8 nm. The adsorption follows second-order kinetics. Langmuir and Freundlich models have been applied to describe the equilibrium data, and the thermodynamic parameters, the Gibbs free energy, ∆G°, enthalpy, ∆H°, and entropy, ∆S°, have been determined. The positive value of ∆H° suggests that the adsorption of heavy metals by the wild herbs is endothermic. The negative values of ∆G° at all the studied temperatures indicate that the adsorption is a spontaneous process. It can be concluded that OR and LV are promising adsorbents for the removal of heavy metals from aqueous solutions over a range of concentrations.

scholarly journals Development, Optimisation and Evaluation of Ketoprofen Lipospheres

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 1853-1863
Author(s):  
Shubhra Rai ◽  
Gopal Rai ◽  
Ashish Budhrani
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Research Work ◽  
Extended Period ◽  
Entrapment Efficiency ◽  
Inflammatory Activity ◽  
Scanning Calorimetry ◽  
Anti Inflammatory

Lipospheres represent a novel type of fat-based encapsulation system produced for the topical drug delivery of bioactive compounds. The goal of this research work was to develop lipospheres, including ketoprofen applied for topical skin drug delivery. Ketoprofen lipospheres were formulated by melt emulsification method using stearic acid and Phospholipon® 90G. The lipospheres were analysed in terms of particle size and morphology, entrapment efficiency, Differential scanning calorimetry, In-vitro drug release, In-vivo (Anti-inflammatory activity). Outcomes of research revealed that particle size was found to be 9.66 µm and entrapment efficiency 86.21 ± 5.79 %. In-vivo, the study of ketoprofen loaded lipospheres formulation shows a higher plain formulation concentration in plasma (5.61 mg/mL). For dermis, ketoprofen retention was 27.02 ± 5.4 mg/mL for the lipospheres formulation, in contrast to that of the plain formulation group (10.05 ± 2.8 mg/mL). The anti-inflammatory effect of liposphere drug delivery systems was assessed by the xylene induced ear oedema technique and compared with marketed products. Finally, it seems that the liposphere drug delivery system possesses superior anti-inflammatory activity as compared to the marketed product gel consistencies. Liposphere may be capable of entrapping the medicament at very high levels and controlling its release over an extended period. Liposphere furnishes a proper size for topical delivery as well as is based on non-irritating and non-toxic lipids; it’s a better option for application on damaged or inflamed skin.

scholarly journals Preparation and preclinical evaluation of aceclofenac loaded pectinate mucoadhesive microspheres

2012 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
Santanu Chakraborty ◽  
Priyanka Nayak ◽  
Bala Murali Krishna ◽  
Madhusmruti Khandai ◽  
Ashoke Kumar Ghosh
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Polymer Concentration ◽  
Research Work ◽  
In Vivo Studies ◽  
Systemic Absorption ◽  
Cross Linking ◽  
Significant Difference

The aim of the present research work was to fabricate aceclofenac loaded pectinate microspheres by ionic gelation method and evaluate the effect of different cross-linking agents and polymer concentration on particle size, encapsulation efficacy and drug release behavior. It was also investigated that whether this pectinate dosage form was able to target the drug release in intestinal region and prevent the different side effect associated with the drug in stomach or not. It was observed that particle size, encapsulation efficacy and in vitro drug release were largely depended on polymer concentration and cross-linking agents. It was also observed that pectinate microspheres showed excellent pH depended mucoadhesive properties and they were able to restrict the drug release in stomach. <em>In vitro</em> drug release study showed that alminium-pectinate microspheres have more sustaining property as compared to barium-pectinate microspheres. Holm-Sidak multiple comparison analysis suggested a significant difference in measured t<sub>50%</sub> values among all the formulations with same cross-linking agent. In vivo studies revealed that the anti inflammatory and analgesic effects induced by pectinate microspheres were significantly high and prolonged as compared to pure drug. So, pectinate microspheres can be an excellent carrier for targeting the delivery of aceclofenac as well as help in improving the patient compliance by prolonging the systemic absorption.

Sethoxydim Response to Spray Carrier Chemical Properties and Environment

1994 ◽  
Vol 8 (3) ◽  
pp. 591-597 ◽  
Author(s):  
John D. Nalewaja ◽  
Robert Matysiak ◽  
Edward Szelezniak
Keyword(s):  
Low Temperature ◽  
Sodium Bicarbonate ◽  
Leaf Surface ◽  
Uv Light ◽  
Chemical Properties ◽  
Ammonium Hydroxide ◽  
Ammonium Salts ◽  
Uv Degradation ◽  
Solution Ph ◽  
Spray Solution

Experiments were conducted to determine the influence of spray carrier salts, UV light, and temperature on sethoxydim phytotoxicity to oat or yellow foxtail. Spray solution pH and ions present were both important to sethoxydim phytotoxicity to oat. Sodium and calcium salts were antagonistic to sethoxydim phytotoxicity only when the spray carrier pH exceeded 7. Ammonium salts and ammonium hydroxide were synergistic with sethoxydim, and the synergism was independent of spray solution pH. Ammonium sulfate, but not ammonium hydroxide, overcame sodium bicarbonate antagonism of sethoxydim. The antagonism of sethoxydim phytotoxicity by sodium bicarbonate was greatest in the presence of UV light and most pronounced when treated plants were exposed to mid-day sunlight. Sodium bicarbonate or low temperature may reduce the speed of sethoxydim absorption allowing for greater UV degradation of unabsorbed sethoxydim on the leaf surface.

Development of Thermal Spray Map for Liquid Feeding Thermal Spray System

2017 ◽  
Vol 866 ◽  
pp. 418-421
Author(s):  
Noppakun Sanpo ◽  
Jirasak Tharajak
Keyword(s):  
Data Mining ◽  
Particle Size ◽  
Thermal Spray ◽  
Experimental Work ◽  
Research Work ◽  
Reference Points ◽  
Range Data ◽  
Spray System ◽  
Liquid Feeding ◽  
Set Up

This research work exhibits a procedure to classify and reorder thermal spray data point so that relationships and correlations between competing processes and materials can be identified. The broad range data mining of published experimental work was performed to create thermal spray map (TS map). A single TS map displayed the correlation between standoff distance (SOD) and feeding particle size is mainly focused. The discussion and evaluation of TS map was taken place. These data mining could be useful to use and/or adapt as reference points for the thermal spray experiment set up in the future.

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