Analysis of the Microwave Heating Effect in the Comminution Efficiency of Iron Ore Particles

2017 ◽  
Vol 899 ◽  
pp. 383-388
Author(s):  
Leonardo Martins da Silva ◽  
M. Nascimento ◽  
I.O. Mota ◽  
E.M. Oliveira ◽  
J.A. Castro
Keyword(s):  
Ultrafine Particles ◽  
Iron Ore ◽  
Fine Particles ◽  
Microwave Energy ◽  
Heating Effect ◽  
Heating And Cooling ◽  
Micro Cracks ◽  
Pellet Feed ◽  
The Magnetic Field ◽  
Scanning Electron

Heating iron ore fine particles using microwave energy has been effective due to the different interactions between minerals and gangue in the magnetic field generated by the microwave. In this way, this paper proposes to use microwave energy to heat the particles of iron ore to promote micro cracks and fissures, which would facilitate the comminution and pulverization process to produce pellet feed. It was analyzed different conditions of heating and cooling in the comminution step. By using techniques of scanning electron microscopy (SEM) and image analysis it was possible to assess and quantify the micro cracks and subsequent analysis of the energy and size fragmentation in the comminution step of ultrafine particles.

scholarly journals On the Recovery of Hematite from an Iron Ore Fine Fraction by Electroflotation Using a Biosurfactant

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1057
Author(s):  
Carolina R. Simões ◽  
Ronald R. Hacha ◽  
Antonio G. Merma ◽  
Maurício L. Torem
Keyword(s):  
Current Density ◽  
Ultrafine Particles ◽  
Iron Ore ◽  
Fine Particles ◽  
Ph Value ◽  
Size Fraction ◽  
Fine Fraction ◽  
Rhodococcus Opacus ◽  
Iron Recovery ◽  
Iron Grade

Electroflotation is a clean technique potentially able to recover fine particles from mineral suspensions. The aim of the present work was to evaluate the electroflotation of fines and ultrafine particles of an itabiritic iron ore using a biosurfactant extracted from Rhodococcus opacus bacteria. Infrared spectroscopy and zeta potential measurements confirmed the interaction between the biosurfactant and the mineral surface. The isoelectric point of hematite presented a value of about pH 5.3; after interacting with the biosurfactant, a charge reversal point of pH 3.5 was observed. The biosurfactant reduced the air/water surface tension from 71 to 40 mN/m, using 25 mg/L concentration. The electroflotation process of fine and ultrafine particles was evaluated as a function of pH, biosurfactant concentration, stirring of the aqueous suspension and current density. It was observed that the iron recovery (%) and iron grade (%) were negatively affected by increasing pH value. Therefore, best results were achieved at pH 3. Biosurfactant concentration and current density positively affected both response variables. An iron recovery value of about 83% and an iron grade of about 59% were achieved for the −38 + 20 µm size fraction; whereas, higher values were attained (98% and 64%, respectively) for the finer size fraction −20 µm.

scholarly journals Effect of particles size range on iron ore flotation

2013 ◽  
Vol 66 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Neymayer Pereira Lima ◽  
George Eduardo Sales Valadão ◽  
Antônio Eduardo Clark Peres
Keyword(s):  
Iron Ore ◽  
Net Present Value ◽  
Fine Particles ◽  
Corn Starch ◽  
Economic Feasibility ◽  
Main Process ◽  
Particle Sizes ◽  
Particle Size Distributions ◽  
Size Fractions ◽  
Pellet Feed

Flotation is one of the main concentration processes being employed for many classes of minerals (sulfides, oxides, silicates, phosphates, for example) at different particle sizes. In the iron ore industry, reverse quartz flotation has been successfully employed for particle sizes below ISOfim after the desliming process. The high demand for iron ore products has made flotation the main process for concentration in this industry, thus a better understanding of its mechanisms and the effect of the particle sizes in the process has become imperative. Flotation tests were carried out with three different size fractions of an itabirite iron ore, obtained using cyclone classification after desliming. The results showed distinct behaviors of the different size ranges. Higher etheramine dosages are required when coarse and fine fractions are floated separately and also this procedure is more sensitive to variations in etheramine dosages and pH values. The differences in particle size distributions and the specific surface area may explain the different flotation behavior of the distinct size fractions. The split flotation circuits for coarse and fine particles indicated an increase of 3% points in the metallurgical recovery with reduction of SiO2 content in final concentrate, increase of etheramine dosage and reduction of corn starch dosage. Economic feasibility analysis indicated a positive net present value of 50 million of dollars with split circuits for coarse and fine particles, considering a production of 10 million tons per year of pellet feed.

Study on Dispersion Behaviors of Oolitic Hematite Ultrafine Particles in Water

2011 ◽  
Vol 383-390 ◽  
pp. 3169-3173
Author(s):  
Fu Sheng Niu ◽  
Shu Xian Liu ◽  
Jin Xia Zhang ◽  
Yi Miao Nie
Keyword(s):  
Water Quality ◽  
Ultrafine Particles ◽  
Iron Ore ◽  
Fine Particles ◽  
Mixing Time ◽  
Selective Flocculation ◽  
Essential Condition ◽  
Dispersing Agent ◽  
Hematite Ore ◽  
Oolitic Hematite Ore

The fine oolitic hematite ore (＜20μm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent use level. In this article, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

Evaluation of Heat Absorption in Iron Ore Using Microwave Energy Source

2014 ◽  
Vol 802 ◽  
pp. 367-372
Author(s):  
L.M. Silva ◽  
M. Nascimento ◽  
I.O. Mota ◽  
Marcio T. Fernandes ◽  
J.A. Castro
Keyword(s):  
Iron Ore ◽  
Phosphorus Content ◽  
Rietveld Method ◽  
Rapid Heating ◽  
Acid Leaching ◽  
Microwave Energy ◽  
Additional Energy ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Short Period

The phosphorus content has significant effect on the steels quality and their applications. The iron ore resources around the world has continuously increased the amount of phosphorous due to the increase of the mining volume with less sterile generation aiming at the efficient utilization of the mining resources, as consequence larger amount of materials with high iron content but with higher phosphorous has been incorporated in the mining body. An alternative to enhance the mining efficiency is to perform a pre treatment of part of the mining body and subsequent blending to attain the acceptable phosphorous in the steelmaking. A viable alternative for reducing the phosphorus content of these residue is to use the acid leaching process which is considered an economical process for the dephosphorization of the iron ore, however, depending on the way the element phosphorus is contained in the ore it will demand additional energy. The objective of the present paper is to study the effective heating and cooling rates of iron ore using microwave energy and its subsequent cooling effect in a short period (thermal shock). Through the X-ray diffraction analysis and applying the Rietveld method it has been possible to demonstrate the mineralogical composition of the iron ore samples and the effect of rapid heating and cooling suitable to promote the fissure formation, thus enhancing the leaching efficiency. The scanning electron microscopy (SEM) was used to analyze the structure of ore due to the effect of its heating and cooling rates.

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.

Titanium Effect on Microstructure and Fracture toughness of Al2O3-BASED Composites

2011 ◽  
Vol 691 ◽  
pp. 32-36
Author(s):  
José G. Miranda-Hernández ◽  
Elizabeth Refugio-García ◽  
Eduardo Térres-Rojas ◽  
Enrique Rocha-Rangel
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Fine Particles ◽  
Ceramic Matrix ◽  
High Energy ◽  
Titanium Content ◽  
Indentation Method ◽  
Sintered Temperature ◽  
Scanning Electron

The effect of different titanium additions (0.5, 1, 2, 3 and 10 vol. %), milling intensity (4 and 8 h) and sintered temperature (1500 and 1600 °C) on microstructure and fracture toughness of Al2O3-based composites was analyzed in this study. After high energy milling of a titanium and Al2O3mixtures, powder mixture presents fine distribution and good homogenization between ceramic and metal. After milling powders during 8 h they were obtained very fine particles with 200 nm average sizes. Microstructures of the sintered bodies were analyzed with a scanning electron microscopy, where it was observed that the microstructure presents the formation of a small and fine metallic net inside the ceramic matrix. From fracture toughness measurements realized by the fracture indentation method, it had that when titanium content in the composite increases, fracture toughness is enhanced until 83% with respect to the fracture toughness of pure Al2O3. This behavior is due to the formation of metallic bridges by titanium in the Al2O3matrix.

Research on Sticking Failure Characteristics of Cemented Carbide Blade

2012 ◽  
Vol 500 ◽  
pp. 211-217
Author(s):  
Zhe Li ◽  
Min Li Zheng ◽  
Xian Zhi Chen ◽  
Meng Tong
Keyword(s):  
Electron Microscopy ◽  
Cutting Tool ◽  
Influence Factors ◽  
Rake Face ◽  
Tool Breakage ◽  
Failure Characteristics ◽  
Micro Cracks ◽  
Cutting Zone ◽  
Element Density ◽  
Scanning Electron

Through the analysis on damaged tool in sticking failure experiment by cutting austenitic stainless steel (1Cr18Ni9Ti) with scanning electron microscopy (SME), found that there are micro cracks existent on rake face near the tip of the cutting tool, through the research of the emergence, development and distribution direction of the crack, the direct reason for tool breakage is the crack being out of control. Combining the study of cutting tool element density change in cutting zone and grooving wear on rake face, this paper analyzed the cause of the binding between chip and tool and the influence factors of sticking failure during the cutting process.

scholarly journals Silylated Thiol-Containing Cellulose Nanofibers as a Bio-Based Flocculation Agent for Ultrafine Mineral Particles of Chalcopyrite and Pyrite

2021 ◽  
Author(s):  
Ana Luiza Coelho Braga de Carvalho ◽  
Feliciana Ludovici ◽  
Daniel Goldmann ◽  
André Carlos Silva ◽  
Henrikki Liimatainen
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Cellulose Nanofibers ◽  
Aqueous Alkaline Medium ◽  
Selective Flocculation ◽  
Turbidity Removal ◽  
Floc Size ◽  
Mineral Particles ◽  
Tailing Ponds ◽  
Anionic Polyacrylamide

AbstractA considerable amount of very fine particles can be found, e.g., stored in tailing ponds, and they can include valuable or hazardous minerals that have the potential to be recovered. Selective flocculation, i.e., the formation of larger aggregates from specific minerals, offers a promising approach to improve the recovery of ultrafine particles. This study focuses on the use of a new bio-based flocculation agent made of silylated cellulose nanofibers containing a thiol-functional moiety (SiCNF). Flocculation was performed in separated systems of ultrafine mineral dispersions of pyrite, chalcopyrite, and quartz in aqueous alkaline medium. The flocculation performance of SiCNF was addressed in terms of the turbidity reduction of mineral dispersions and the floc size, and the results were compared with the performance of a commercial anionic polyacrylamide. SiCNF exhibited a turbidity removal efficiency of approximately 90%–99% at a concentration of 4000–8000 ppm with chalcopyrite and pyrite, whereas the turbidity removal of quartz suspension was significantly lower (a maximum of approximately 30%). The sulfide particles formed flocs with a size of several hundreds of micrometers. The quartz in turn did not form any visible flocs, and the dispersion still had a milky appearance after dosing 12,000 ppm of the flocculant. These results open a promising path for the investigation of SiCNF as a selective flocculation agent for sulfide minerals. Graphical Abstract

scholarly journals CHARACTERIZATION AND STUDY OF THE KINETICS OF SEDIMENTATION OF REJECT OF THE IRON ORE INDUSTRY

2018 ◽  
Vol 15 (30) ◽  
pp. 647-653
Author(s):  
J. H. M. SANTOS ◽  
P. C. M. SANTOS ◽  
F. T. VIEIRA ◽  
J. D. FABRIS ◽  
A. B. REIS ◽  
...  
Keyword(s):  
Iron Ore ◽  
Negative Impact ◽  
Mining Industry ◽  
Water Recovery ◽  
Recycle Water ◽  
Industrial Activity ◽  
The Earth ◽  
Energy Spectrometer ◽  
Kinetics Of ◽  
Scanning Electron

Currently the mining industry plays an important role in the generation of wealth of a country through the exploitation of natural resources of the earth, and in some cases, responsible for a significant fraction of the economic matrix. Like any other industrial activity, mining has a negative impact on the environment, which leads the industry to constantly face the challenge of achieving the sustainability of its activities. The study aimed to characterize the iron ore reject seeking the feasibility of reprocessing and water recovery. The reject sample was characterized using Scanning Electron Microscopy with Dispersive Energy Spectrometer. Studies of the sedimentation kinetics of the tailings were carried out to implement techniques to recover the iron present in the tailings and recycle water in the mineral processing. In the sedimentation tests it was possible to recover approximately 50% of water without compromising the transport operations of the material. It can be concluded that the ore reject analyzed is composed mainly of Fe and Si respectively, showing that the reject has reprocessing potential, and recovery of water present in the clarified.

A Study of Airborne Wear Particles Generated From a Sliding Contact

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Ulf Olofsson ◽  
Lars Olander ◽  
Anders Jansson
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Urban Environments ◽  
Airborne Particles ◽  
Wear Particles ◽  
Coarse Particles ◽  
Sliding Velocity ◽  
Airborne Particle ◽  
Particle Generation ◽  
Pin On Disk

Recently, much attention has been paid to the influence of airborne particles in the atmosphere on human health. Sliding contacts are a significant source of airborne particles in urban environments. In this study airborne particles generated from a sliding steel-on-steel combination are studied using a pin-on-disk tribometer equipped with airborne-particle counting instrumentation. The instrumentation measured particles in size intervals from 0.01μm to 32μm. The result shows three particle size regimes with distinct number peaks: ultrafine particles with a size distribution peak around 0.08μm, fine particles with a peak around 0.35μm, and coarse particles with a peak around 2 or 4μm. Both the particle generation rate and the wear rate increase with increasing sliding velocity and contact pressure.

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