scholarly journals Deashing and desulfurization of subbituminous coal from the East field (Bogovina Basin, Serbia) - insights from chemical leaching

2021 ◽  
pp. 61-61
Author(s):  
Katarina Pantovic-Spajic ◽  
Branislav Markovic ◽  
Miroslav Pavlovic ◽  
Miroslav Sokic ◽  
Snezana Zildzovic ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
Acid Leaching ◽  
Acid Mixture ◽  
X Ray Diffraction ◽  
Chemical Leaching ◽  
Leaching Process ◽  
Acid Ph ◽  
Different Temperatures ◽  
Coal Organic Matter

The study is focused to determine the most effective chemical leaching process for simultaneous demineralization/deashing and desulfurization of subbituminous coal from the Bogovina Basin. Coal was treated for 30 minutes, at different temperatures, using variable concentrations of hydro-chloric, nitric, acetic and citric acids; hydrogen peroxide, mixture of hydrogen peroxide and nitric acid (pH 2), as well as by the stepwise leaching process (nitric acid + mixture of hydrogen peroxide and nitric acid, pH 2). The changes in mineral composition, caused by chemical leaching, are followed using X-ray diffraction, whereas alterations of coal organic matter are tracked by Fourier-transform infrared spectroscopy and content of fixed carbon. Inorganic acid leaching, regardless of temperature and acid concentration, enabled successful deashing of coal, whereas percent of desulfurization was insufficient. Organic acid leaching was not satisfactory for both, deashing and desulfurization. Leaching by H2O2 and H2O2/HNO3 mixture (pH 2) resulted in moderate desulfurization, but ash reduction was low. The most suitable method for simultaneous effective ash (78 wt.%) and sulfur (66 wt.%) removal from Bogovina coal is the two-step leaching, combining 10 vol.% HNO3 and mixture of 35 vol.% H2O2/10 vol.% HNO3 of pH 2 at 60?C.

scholarly journals Research of Polymetallic Sulfide Industrial Waste Nitric Acid Treatment

2017 ◽  
Vol 2 (2) ◽  
pp. 174
Author(s):  
Rogozhnikov D.A. ◽  
Dizer O.A. ◽  
Shoppert A.A.
Keyword(s):  
Nitric Acid ◽  
Industrial Waste ◽  
Mutual Influence ◽  
Acid Leaching ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Mathematical Methods ◽  
X Ray ◽  
Nitric Acid Leaching ◽  
Kinetic Features

<p>Thermodynamic and kinetic features studies of polymetallic sulfide industrial waste nitric acid leaching were carried out. Elemental and phase composition of investigated raw material were studied with X-ray diffraction and electron microscopy methods. Calculations of the Gibbs energy change for the likely reactions of sulfide minerals with nitric acid were performed. In order to determine the most probable conditions of the sulfide industrial waste leaching in nitric acid, as well as the mutual influence of the produced pulp components on the performance of the process, the kinetics evaluation of multicomponent sulfide industrial waste in a nitric medium was studied using mathematical methods.</p>

Hydrogen Peroxide Decomposition in an Environmentally Friendly Pickling Solution for AISI 316L Stainless Steel

CORROSION ◽  
2005 ◽  
Vol 61 (1) ◽  
pp. 21-29 ◽  
Author(s):  
L. Narváez ◽  
E. Cano ◽  
J. M. Bastidas
Keyword(s):  
Hydrogen Peroxide ◽  
Stainless Steel ◽  
Environmentally Friendly ◽  
Acid Mixture ◽  
Ferric Ion ◽  
Aisi 316L ◽  
Pickling Solution ◽  
Peroxide Decomposition ◽  
Different Temperatures ◽  
Ion Contents

Abstract There is increasing interest in the utilization of ecological bath solutions for the pickling of stainless steel (SS), because conventional nitric (HNO3) and hydrofluoric (HF) acid mixtures generate high NOx emissions. A mixture of hydrogen peroxide (H2O2), sulfuric acid (H2SO4), and HF has been tested in this study as an environmentally friendly pickling solution for AISI 316L SS (UNS S31603). The decomposition of H2O2 and the H2SO4-HF-H2O2 mixture was assessed at different temperatures from 25°C to 60°C, with ferric ion contents from 0 to 40 g/L, with and without stirring of the aqueous acid mixture. The p-Toluene sulfonic, 3-hydroxybenzoic, and 4-dodecylbenzene sulfonic acids were tested as stabilizers for H2O2. The AISI 316LSS pickling rate found at 50°C was 2.35 × 103 mg/dm2-day (mdd) and 0.12 × 103 mdd, respectively, in the absence and presence of 40 g/L ferric ion.

scholarly journals Preliminary Study for the Determination of Rare Earth Elements Using the ICP-MS Technique

2020 ◽  
Vol 71 (4) ◽  
pp. 277-288
Author(s):  
Gina Alina Catrina (Traistaru) ◽  
Gabriela Geanina Vasile ◽  
Ionut Nicolae Cristea ◽  
Georgiana Cernica ◽  
Cristina Ileana Covaliu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Rare Earth ◽  
Nitric Acid ◽  
Rare Earth Elements ◽  
Aqua Regia ◽  
Calcination Process ◽  
Icp Ms ◽  
Different Temperatures ◽  
Digestion Methods

This paper proposes an optimized method for the determination of rare earth elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) from soils using ICP-MS technique. First, the soil samples were thermal treated at three different temperatures 550ºC, 700ºC and 8500C in order to eliminate organic matter interferences. Then, the residual samples remaining from the calcination process were extracted in acidic medium with two different digestion methods (method I - a mixture of nitric acid and hydrogen peroxide; method II - aqua regia mixture) in order to quantify rare earth elements content. The highest recovery percentages for the major rare earth elements analyzed (Sc, Y, La, Ce, Pr, Nd. Sm) were situated in the range 86.13% to 99.90%, in sample residues thermally treated at 700�C and extracted with nitric acid and hydrogen peroxide.

Recovery of Nickel and Cobalt from Dimethyldithiocarbamate Precipitation of Pyrolusite Leaching Process

2013 ◽  
Vol 634-638 ◽  
pp. 258-262 ◽  
Author(s):  
Hai Feng Su ◽  
Bo Ji Li ◽  
Qing Lu ◽  
Yan Xuan Wen ◽  
Jing Su
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Acid Leaching ◽  
Sulfuric Acid Leaching ◽  
Leaching Process ◽  
Sulfuric Acid Medium ◽  
Cobalt Recovery ◽  
Reductive Leaching ◽  
High Nickel ◽  
Leaching Condition

Dimethyldithiocarbamate precipitation is a secondary resource containing nickel and cobalt, which are formed by adding sodium dimethyldithiocarbamate to purify the neutralized filtrate of pyrolusite reductive leaching process. The extraction of nickel and cobalt from dimethyldithiocarbamate precipitation was investigated using nitric acid as oxidant in dilute sulfuric acid medium in this paper. The effects of concentrations of nitric acid and sulfuric acid, leaching temperature as well as reaction time were discussed. The results showed that high nickel and cobalt recovery could be obtained by analyzing the leaching efficiencies of nickel and cobalt during the leaching process. The optimal leaching condition was 1.47 mol/L H2SO4 and 1.16 mol/L HNO3 for 30 min at 45 °C while using particles smaller than 0.420 mm. And the leaching efficiencies were 98% for Co and 95% for Ni, respectively.

Preliminary Study on the Effect of Sulphuric Acid to Nitric Acid Mixture Composition, Temperature and Time on Nitrocellulose Synthesis Based Nata de Coco

2021 ◽  
Vol 317 ◽  
pp. 312-319
Author(s):  
Nursyafiqah Jori Roslan ◽  
Siti Hasnawati Jamal ◽  
Keat Khim Ong ◽  
Wan Md Zin Wan Yunus
Keyword(s):  
Nitric Acid ◽  
Nitrogen Content ◽  
Sulphuric Acid ◽  
Hydroxyl Group ◽  
Acid Mixture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Reaction ◽  
Preliminary Study ◽  
Low Nitrogen

Nitrogen content is a paramount significance in predicting nitrocellulose. Nitrocellulose with high nitrogen content (>12.5%) can be used for propellant, while low nitrogen content (<12.5%) can be applied for the production of ink, paint and leather finishes. In this preliminary study, the effect of mole ratio of sulphuric acid to nitric acid, reaction temperature and time towards nitrogen content in nitrocellulose was investigated. Nitrocellulose was synthesized using nata de coco as bacterial cellulose source via nitration method. Nitrocellulose with percentage of nitrogen content of 11.74% to 12.75% was obtained when 2 to 4 mole ratio of sulphuric to nitric acid was used with operating temperature and time ranging 20°C to 40°C and 20 minutes to 40 minutes respectively. Analysis of Fourier transform infrared (FTIR) displayed the reduction of hydroxyl group in nitrocellulose proving that several hydroxyl group in cellulose was successfully replaced by nitryl group. Other characterizations such as elemental analyser, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were evaluated to support the result.

One-Step Oxidation of Benzene Producing Eight High Value Compounds Using Nitric Acid and Hydrogen Peroxide

2015 ◽  
Vol 19 (0) ◽  
pp. 55-58
Author(s):  
Zhen-xue Liu ◽  
◽  
Zhong-xue Gan ◽  
Jun-jie Gu ◽  
Qing-feng Song
Keyword(s):  
Hydrogen Peroxide ◽  
Nitric Acid ◽  
One Step ◽  
Oxidation Of Benzene

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

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