A Thermodynamic Analysis of the Selective Sulphidation of Nickel from a Nickeliferous Lateritic Ore

2012 ◽  
Vol 31 (4-5) ◽  
pp. 603-611 ◽  
Author(s):  
C. T. Harris ◽  
C. A. Pickles ◽  
J. G. Peacey
Keyword(s):  
Liquid Solution ◽  
Production Method ◽  
Pure Component ◽  
Maximum Amount ◽  
Iron Sulphide ◽  
Nickel Sulphide ◽  
Potential Production ◽  
Percent Nickel ◽  
Lateritic Ore ◽  
Thermodynamic Basis

AbstractThe production of a nickel sulphide concentrate through selective sulphidation of a nickeliferous lateritic ore at temperatures lower than current smelting temperatures, is being studied as a potential production method for upgrading lateritic ores. The ability to produce such a nickel sulphide concentrate at economically attractive grades, while achieving reasonable nickel recoveries, relies on the conversion of the maximum amount of nickel oxide to sulphide, while minimizing the amount of iron sulphide. This paper examines the thermodynamic basis for this selective sulphidation. The analysis includes both pure component equilibrium as well as various solid and liquid solution phases, which are anticipated to set limits on the maximum achievable grade/recovery combinations. Thermodynamic calculations show that, for high iron limonitic ores, grades of up to 20 to 25 mass percent nickel should be possible, while maintaining recoveries of greater than 80 percent.

scholarly journals An overview of potential production of bio-lubricant in Indonesia

2022 ◽  
Vol 951 (1) ◽  
pp. 012061
Author(s):  
L Mairiza ◽  
Zuhra ◽  
M Khadafi ◽  
Muhibbul ◽  
I Budiman ◽  
...  
Keyword(s):  
Rice Bran ◽  
Palm Oil ◽  
Raw Materials ◽  
Production Method ◽  
Rice Production ◽  
The Other ◽  
Raw Material ◽  
Crude Palm Oil ◽  
Potential Production ◽  
Oil Reserves

Abstract The European Union’s embargo on Indonesian crude palm oil (CPO) has resulted in excess of domestic palm oil reserves. The embargo has resulted in a build-up of domestic CPO due to the fact that the majority of Indonesia’s CPO production is exported overseas. The CPO price has dropped in recent months as a result of CPO overstock. On the other hand, as a by-product of rice production, Indonesia produces millions of tons of rice bran. The bran is treated more as waste than a resource for raw material to produce valuable products, such as bran oil. The need for lubricants in Indonesia is expected to rise as the number of cars and industries grows. As a result, some lubricant requirements must be met through importation because domestic manufacturing is insufficient. Palm oil and bran oil are both excellent candidates for conversion into biolubricants. This paper looks at the possibility of biolubricant production in Indonesia using alternate raw materials rather than petroleum-based sources. The paper begins by detailing the country’s lubricant demand, then moves on to the probable availability of biolubricant raw materials in Indonesia, and finally to the biolubricant process production method.

Statistical analysis of classification

1966 ◽  
Vol 24 ◽  
pp. 188-189
Author(s):  
T. J. Deeming
Keyword(s):  
Multivariate Analysis ◽  
Statistical Analysis ◽  
Classification Scheme ◽  
Analytical Procedure ◽  
Narrow Band ◽  
Scientific Research ◽  
Maximum Amount ◽  
Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

Electron Microscopic Analysis of Myonecrosis Induced by a Pure Component Isolated From Rattlesnake Venom

1976 ◽  
Vol 34 ◽  
pp. 292-293
Author(s):  
Charlotte L. Ownby ◽  
David Cameron ◽  
Anthony T. Tu
Keyword(s):  
Gel Filtration ◽  
Microscopic Analysis ◽  
The United States ◽  
Exchange Chromatography ◽  
Pure Component ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Mouse Muscle ◽  
Major Health Problem ◽  
Rattlesnake Venom

In the United States the major health problem resulting from snakebite poisoning is local tissue damage, i.e. hemorrhage and myonecrosis. Since commercial antivenin does not usually prevent such damage to tissue, a more effective treatment of snakebite-induced myonecrosis is needed. To aid in the development of such a treatment the pathogenesis of myonecrosis induced by a pure component of rattlesnake venom was studied at the electron microscopic level.The pure component, a small (4,300 mol. wt.), basic (isoelectric point of 9.6) protein, was isolated from crude prairie rattlesnake (Crotalus viridis viridis) venom by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25), and shown to be pure by electrophoresis. Selection of the myotoxic component was based on light microscopic observations of injected mouse muscle.

Fractionation of polymethylene chains: An electron crystallographic investigation

1986 ◽  
Vol 44 ◽  
pp. 794-795
Author(s):  
Douglas L. Dorset
Keyword(s):  
Cross Section ◽  
Binary Systems ◽  
Linear Chain ◽  
Pure Component ◽  
Organic Substrates ◽  
Crystallographic Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Sizes ◽  
The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

Studies of copper selenide ultrafine particles by newly developed gas evaporation method

1990 ◽  
Vol 48 (4) ◽  
pp. 306-307
Author(s):  
Chihiro Kaito ◽  
Yoshio Saito
Keyword(s):  
Crystal Structure ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Production Method ◽  
Atmospheric Temperature ◽  
Copper Selenide ◽  
Quartz Boat ◽  
Selenium Vapor ◽  
Ar Gas ◽  
Ultra Fine Particles

The direct evaporation of metallic oxides or sulfides does not always given the same compounds with starting material, i.e. decomposition took place. Since the controll of the sulfur or selenium vapors was difficult, a similar production method for oxide particles could not be used for preparation of such compounds in spite of increasing interest in the fields of material science, astrophysics and mineralogy. In the present paper, copper metal was evaporated from a molybdenum silicide heater which was proposed by us to produce the ultra-fine particles in reactive gas as shown schematically in Figure 1. Typical smoke by this method in Ar gas at a pressure of 13 kPa is shown in Figure 2. Since the temperature at a location of a few mm below the heater, maintained at 1400° C , were a few hundred degrees centigrade, the selenium powder in a quartz boat was evaporated at atmospheric temperature just below the heater. The copper vapor that evaporated from the heater was mixed with the stream of selenium vapor,and selenide was formed near the boat. If then condensed by rapid cooling due to the collision with inert gas, thus forming smoke similar to that from the metallic sulfide formation. Particles were collected and studied by a Hitachi H-800 electron microscope.Figure 3 shows typical EM images of the produced copper selenide particles. The morphology was different by the crystal structure, i.e. round shaped plate (CuSe;hexagona1 a=0.39,C=l.723 nm) ,definite shaped p1 ate(Cu5Se4;Orthorhombic;a=0.8227 , b=1.1982 , c=0.641 nm) and a tetrahedron(Cu1.8Se; cubic a=0.5739 nm). In the case of compound ultrafine particles there have been no observation for the particles of the tetrahedron shape. Since the crystal structure of Cu1.8Se is the anti-f1uorite structure, there has no polarity.

COMPUTER MODELING OF CHEMICAL EQUILIBRIUMS IN WO3–H2O SYSTEM

2017 ◽  
pp. 35-48 ◽  
Author(s):  
V.P. Bondarenko ◽  
O.O. Matviichuk
Keyword(s):  
Transition Temperature ◽  
Gas Phase ◽  
Single Phase ◽  
Reference Data ◽  
Maximum Amount ◽  
Reaction Products ◽  
Influence Of Temperature ◽  
Equilibrium Chemical ◽  
Program Data ◽  
Good Agreement

Detail investigation of equilibrium chemical reactions in WO3–H2O system using computer program FacktSage with the aim to establish influence of temperature and quantity of water on formation of compounds of H2WO4 and WO2(OH)2 as well as concomitant them compounds, evaporation products, decomposition and dissociation, that are contained in the program data base were carried out. Calculations in the temperature range from 100 to 3000 °С were carried out. The amount moles of water added to 1 mole of WO3 was varied from 0 to 27. It is found that the obtained data by the melting and evaporation temperatures of single-phase WO3 are in good agreement with the reference data and provide additionally detailed information on the composition of the gas phase. It was shown that under heating of 1 mole single-phase WO3 up to 3000 °С the predominant oxide that exist in gaseous phase is (WO3)2. Reactions of it formation from other oxides ((WO3)3 and (WO3)4) were proposed. It was established that compound H2WO4 is stable and it is decomposed on WO3 and H2O under 121 °C. Tungsten Oxide Hydrate WO2(OH)2 first appears under 400 °С and exists up to 3000 °С. Increasing quantity of Н2О in system leads to decreasing transition temperature of WO3 into both liquid and gaseous phases. It was established that adding to 1 mole WO3 26 mole H2O maximum amount (0,9044–0,9171 mole) WO2(OH)2 under temperatures 1400–1600 °С can be obtained, wherein the melting stage of WO3 is omitted. Obtained data also allowed to state that that from 121 till 400 °С WO3–Н2O the section in the О–W–H ternary system is partially quasi-binary because under these temperatures in the system only WO3 and Н2O are present. Under higher temperatures WO3–Н2O section becomes not quasi-binary since in the reaction products WO3 with Н2O except WO3 and Н2O, there are significant amounts of WO2(OH)2, (WO3)2, (WO3)3, (WO3)4 and a small amount of atoms and other compounds. Bibl. 12, Fig. 6, Tab. 5.

The technological transformation of Russia's industrial sectors: Difficulties and prospects

2020 ◽  
Vol 16 (9) ◽  
pp. 1674-1697
Author(s):  
O.P. Smirnova ◽  
A.O. Ponomareva
Keyword(s):  
Production Method ◽  
Industrial Sector ◽  
The State ◽  
Industrial Complex ◽  
Economic Activities ◽  
Resource Saving ◽  
Technological Transformation ◽  
Modern Approach ◽  
Industrial Enterprises ◽  
Industrial Sectors

Subject. The article focuses on contemporary trends in the industrial and socio-economic development of Russia during the technological transformation of its sectors. Objectives. The study is an attempt to analyze what opportunities and difficulties may arise for the development of the industrial sectors in Russia. We also examine the dynamics of key development indicators of the industrial sectors, point out inhibitors of their competitiveness. Methods. The methodological framework comprises general methods of systems, structural-functional and comprehensive approaches to analyzing economic phenomena. We applied graphic, economic-statistical methods of research, conventional methods of grouping, comparison and generalization, and the logic, systems and statistical analysis. Results. We display how industrial sectors develop over time by type of economic activities. The article provides the rationale for structural rearrangements and further innovation-driven development of the industries. We display that the Russian industries technologically depend om imported production technologies. We substantiate the renewal of assets and technologies at industrial enterprises, and retain and develop human capital. Conclusions and Relevance. Primarily, the Russian economy should be digitalized as a source of the long-term economic growth. Notably, industrial enterprises should replace their linear production method with that of the circular economy and implement resource-saving innovative technologies. The State evidently acts as the leading driver of technological retrofitting of the industrial sector. If the State holds the reasonable and appropriate industrial policy at the federal and regional levels and configure its tools to ensure the modern approach to developing the industries in a competitive fashion, the industrial complex will successfully transform into the innovative economy.

Uşak İli’nden Toplanan Taxus Baccata (L) Türünün Metanol Ekstresinin Yaprak, Dal ve Meyvesinde Biyolojik Aktivitenin Belirlenmesi

2019 ◽  
Vol 7 (10) ◽  
pp. 1533
Author(s):  
Yasemin Karafakıoglu
Keyword(s):  
Antioxidant Activity ◽  
Methanol Extract ◽  
Phenolic Content ◽  
Maximum Amount ◽  
Chemical Components ◽  
Taxus Baccata ◽  
Dpph Radical ◽  
Flavonoid Content ◽  
Future Studies ◽  
Different Parts

Taxus species in different parts of the world prevent the formation of hepatoprotective, anticoagulant, antiulcerogenic, anti-coagulant, antifungal and tumour cells. In this study, biological activity studies were performed on the leaves, branches and fruits of the methanol extract of Taxus baccata L. species collected from Sivaslı district of Uşak province. The methanol extract of the T.baccata species, the total amount of phenolic content of the sample was found to be 14.76 mg GAEQ/1g dry sample in the highest leaves. In T.baccata methanol extract, the maximum amount of flavonoid content was 0.468±mg QE/g dry sample. Antioxidant activity value as DPPH radical; % inhibition value was found as 93.21%. Based on the results; It can be concluded that the leaves of T.baccata have higher antioxidant activity than fruits and branches. Future studies need to explore the chemical components contained in the T.baccata species to determine and investigate in further detail.

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

2019 ◽  
Author(s):  
Matěj Velický ◽  
Sheng Hu ◽  
Colin R. Woods ◽  
Peter S. Toth ◽  
Viktor Zólyomi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Boron Nitride ◽  
Electron Tunneling ◽  
Hexagonal Boron Nitride ◽  
Large Body ◽  
Liquid Solution ◽  
Limiting Current ◽  
Electron Transfer Rate Constant ◽  
Electrochemical Parameters ◽  
Voltammetric Measurements

Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

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