Ni-Silicides nanoparticles as substitute for noble metals for hydrogenation of nitrobenzene to p-Aminophenol in sulfuric acid

2016 ◽  
Vol 520 ◽  
pp. 151-156 ◽  
Author(s):  
Zhen Dong ◽  
Tao Wang ◽  
Jie Zhao ◽  
Teng Fu ◽  
Xuefeng Guo ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Noble Metals ◽  
Ni Silicides

scholarly journals OBTAINING SOME THERMOD AINING SOME THERMODYNAMIC PARAMETERS CONTAINING ME AINING METACRYLATE AND ALL TE AND ALLYL GROUPS CON YL GROUPS CONTAINING IN COMPOSITION

2019 ◽  
Vol 2019 (1) ◽  
pp. 69-75
Author(s):  
Kh Akhmedov ◽  
Zh Bekpulatov ◽  
G Solijonova ◽  
N Sharifova
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Noble Metals ◽  
Material Composition ◽  
Rational Analysis ◽  
Sulfuric Acid Treatment ◽  
Chemical Assay ◽  
Sulfide Ore ◽  
Content Of Gold ◽  
Gold Bearing

The article discusses the results of studying the material composition and the development of technology for processing gold-bearing sulfide ore samples. The material composition of the ore samples was studied by spectral, chemical, assay and rational analysis of gold and silver. Based on a study of the material composition of the ore samples, the following conclusions were made: gold and silver are the industry's most valuable components. It is shown that the use of sulfuric acid treatment of a cinder of graviofloraf concentrate can allow to improve the technological performance of the process. As a result of the mixture of gravio-flotation concentrate after sulfuric acid treatment drying, grinding to a size of 95% CL. -0,074+0 mm and subjected to sorption cyanidation. In the initial cake, the content of gold -77.83 u. e. and silver-16.3 u. e., the concentration of sodium cyanide 0.15%, the ratio W:t=2:1; resin AM-2B-5% of the pulp volume, the duration of cyanidation 36 hours.the Content in the tailings of cyanidation of gold - 6.5 u. e., and silver - 4.8 u. e. the Extraction of noble metals in solution and on the resin was 91.65 and 70.55%, respectively. Through extraction of 87.63% gold and 55.6% silver from ore.

scholarly journals The Study Of The Selection Of Lead-Copper Concentrate By The Sulfite Method

2021 ◽  
Vol 03 (03) ◽  
pp. 13-21
Author(s):  
Markhamat Akramovna Mutalova ◽  
◽  
Nargiza Abdurasulovna Abdurakhmanova ◽  
Keyword(s):  
Sulfuric Acid ◽  
Noble Metals ◽  
Sodium Sulfite ◽  
Copper Concentrate ◽  
Selection Processes ◽  
Selection Of

Currently, sulfoxide methods are of greatest interest for the practice of separation of lead-copper concentrates. The selection processes based on the use of sulfoxides such as sulfuric acid, sulfite salts, etc. should be included in this subgroup.d. Typically, these reagents are used in combination with other depressors [3]. The main advantage of sulfoxide methods is the lack of dissolution of noble metals and higher efficiency compared to many known methods. The subgroup under consideration includes a method using sodium sulfite, iron vitriol and sulfuric acid for halenite depression Currently, about thirty methods of flotation separation of lead-copper concentrates are known.

scholarly journals Hydrometallurgical Processing of the Wastes of Polymetallic Ore Dressing

2020 ◽  
Author(s):  
Aleksander Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Noble Metals ◽  
Ferrous Metal ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Gold Recovery ◽  
Flotation Tailings ◽  
Hydrometallurgical Processing ◽  
Two Samples ◽  
Sulfide Concentrates

The possibility of hydrometallurgical treatment of old flotation tailings to extract base and noble metals was investigated. Two samples of old flotation tailings samples containing 0.26% and 0.36% of copper, and 0.22% and 0.23% of zinc were the subjects of this study. Agitation and percolator leaching was performed with distilled water and sulfuric acid solutions (of 0.5 to 10% H2SO4). It was shown that under certain conditions (sulfuric acid concentration) it was possible to achieve selective leaching of non-ferrous metals and obtain solutions with relatively low concentrations of iron ions, which is necessary for further effective extraction of non-ferrous metal ions from the solution. The effect of acid leaching on further gold recovery from the first sample containing 0.7 g/t of gold by cyanidation was investigated. The sample of the tailings after leaching with a 1% sulfuric acid solution was leached with 10% sulfuric acid. After that, the tailings sample and the acid leach residues were subjected to sorption cyanidation. Two-stage acid leaching with 1 and 10% sulfuric acid provided the higher gold recovery than one-stage (49 and 65%, respectively). Also it was shown that pregnant solution obtained during leaching of the second sample with 10% sulfuric acid may be used for oxidative leaching of substandard copper-zinc concentrate that allowed to 13 and 48% of copper and zinc from the concentrate during the leaching at 80∘C. Keywords: flotation tailings, leaching, substandard sulfide concentrates

scholarly journals Kinetics of Dissolution of Copper-Zinc Alloy in Nitric-Sulfuric Acid Solutions

2019 ◽  
pp. 214-221
Author(s):  
Natalya М. Vostrikova ◽  
Elena D. Kravtsova
Keyword(s):  
Sulfuric Acid ◽  
Noble Metals ◽  
Chemical Processes ◽  
Zinc Alloy ◽  
Acid Solutions ◽  
Copper Zinc ◽  
Kinetics Of Dissolution ◽  
Sulfuric Acid Solutions ◽  
Kinetics Of ◽  
Base Substrate

Studies were carried out on the dissolution of a copper-zinc alloy imitating a base substrate of an electron scrap containing noble metals in nitric-sulfuric acid solutions. A mathematical model is obtained that allows calculating the rate of copper and zinc transition to nitric-sulfuric solutions by varying the concentration of H+ ions from 1 to 4 g-ion / dm3 and NO3 – ions from 0,5 to 1,0 g-ion / dm3. In the range of concentrations of H+ and NO3 – ions studied, the maximum rate of copper transition into the solution is 6,5·10–5, and zinc is 4,5·10–5 kg / m2s. The equation of regression allowing to carry out a choice of conditions for proceeding with necessary speed of the chemical processes taking place in metallurgical practice is presented

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

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