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By Masoud Askari, Ahmad Rafizadeh, Shahamat Rostami, Mohammad Qaredaqi

Gole - Gohar Iron ore mines located in Sirjan, Southeast of Iran, have more than 1 billion Iron ore deposit and this area comprises 45 % of Iran Iron reservoirs. The aim of Wet tailing processing line is recovering Hematite ore from wet tailing of Gole - Gohar iron ore processing plant. The Investigations of Hematite recovery plant showed that the recovery of Iron ore to concentrate in Wet Tailing Processing (WTP) line is very lower than that has been predicted, sampling, and designing of the process parameters are not accurate and designed magnetic field intensity is not reasonable for the recovery of Iron in form of Hematite in this line feed. Applying of MIMS in WTP separator and changes in circuit caused in overwhelming increase of Fe recovery, from 11 to 40%. Although recovery of WTP line was improved, but low recovery of this processing line and high content of Hematite ore in WTP tailing, made applying Wet High Intensity Magnetic separators unavoidable. Two kinds of WHIMS have tested for processing of WTP line tailing. Results showed that traditional Jones separator with grooved plate matrix, is more suitable to achieve a better quality of concentrate compared to Slon® separator.

Jan 1, 2014

By Gianni Shena, Francesco Montanari

"Recent improvements in the resolution of X-ray computed tomography (CT) make it a promising alternative to traditional time consuming, error prone laboratory procedures for mineral liberation analysis, such as heavy liquid fractioning and measurements on polished sections. All indications are that in a few years CT will be well-established in many laboratories as a rapid technique for accurate liberation studies. In this scenario it would be able to provide liberation spectra or washability data in tens of minutes following sampling. However, although CT is a fast evolving technology, its on-line application is unlikely in the foreseeable future.Dual-energy (DE) radiography is another X-ray technique originating from non-destructive evaluation (NDE) and medical fields, which allows retrieval of the volumetric content of valuable components from two-phase particles in a fraction of second. Two radiographic images at different X-ray energies of a single particle or a monolayer of particles are taken in short time sequence. The thickness of the two phases is calculated particle by particle by image subtraction, whereupon particle grades can be derived. The development of the method for on-line applications requires the presentation of non-overlapping particles in the gap in the X-ray source detector measurement couple. Straightforward extension of the principle to multiphase systems is not possible. The paper reviews the state of the art of these two techniques as applied to mineral liberation problems."

Jan 1, 2003

By Q. Shi

An investigation into the hydrophobic aggregation of ultrafine smithsonite in surfactant solution has been undertaken through a combination of hydrophobic flocculation experiments, zeta potential measurements, surface tension measurements, and contact angle measurements. The experimental results have revealed that the behaviors of hydrophobic aggregation were closely correlated with the particle hydrophobicity, but they were not lowered byte change of the particle surface charges due to surfactants adsorption. On the other hand, the liquid (solution) surface tension (?LV) plays an important role in hydrophobic aggregation, and the hydrophobic aggregation could not occur below the critical liquid (solution) surface tension (?c). Meanwhile, this flocculation has been observed to require sufficient stirring strength and magnitudes of kinetic energy input to achieve the maximum aggregation degree. From the microflotation results, it has been found that the flotation kinetics response of smithsonite fines is markedly improved due to sufficient stirring strength, and the stirring strength influenced the floc flotation in a manner quite similar to their influence on the hydrophobic aggregation, suggesting that the formation of hydrophobic flocs is a promising means to recover smithsonite in the fine size range.

Sep 1, 2012

By B. Das

Waste water produced from coal preparation plants posses several problems during dewatering and solid/liquid separation. The natural sedimentation rate of the particles present in colloidal and finely divided suspended form is very slow. Flocculation technology is being applied in most of the coal washeries to recover water which is being accomplished through the use of inorganic salts, polymeric flocculants or both depending on the chemical and physical characteristics of the pollutants present in the waste water. The waste tailing water from Piperware coal preparation plant, Central Coalfield Limited (CCL), India, is highly turbid containing ~ 16000 NTU with negative surface charge in the pH range of 2 to 10. Polymeric flocculants in conjunction with fine magnetite is investigated to achieve faster settling rate with lowest level of water turbidity. The conditions affecting the interaction between the reagents and the turbid particles present in the tailings water are investigated. It is possible to bring down the turbidity of the water to < 90 NTU from very high turbid tailing water by using 2 mg/L of the polymeric flocculent in combination with 0.1 g/L of magnetite at natural pH of the tailing slurry. It has been found that finely divided positively charged magnetite particles in combination with the flocculent selectively coat the negatively charged impurities present in water and thereby increase the settling rate under the influence of a magnetic field.

Jan 1, 2014

By Vishal Shukla, Ashok Kumar, Manas Ranjan, D. Chakraborty, Narayan Sharma

Jigging has a very important role in mineral processing Industry. Upgrading of Iron Ore by jigging has been an emerging trend. A detailed investigation is carried out to understand the influence of Jig feed granulometry and bed height during jigging operation. Noamundi jig plant data shows that variation in jig feed granulometry, feed quality and bed height are major contributors to fluctuation in jigging performance. At Noamundi the feed size (-10.0+0.5mm) fraction is used for fines jigging operation. To understand the effect of granulometrey on jig plant performance such as yield, separation efficiency and Fe recovery. In this context The performance of jigging was evaluated by daily average data from jig operation was used to study the influence of feed distribution on jigging performance .Coarser fraction (+6mm) has a positive influence , whereas fines fraction (-0.5mm) tends to lower performance . During Jigging rearrangements of Particles takes place due to an alternate expansion and compaction of Jig Bed .These particles are arranged by increasing density from top to bottom. During the particle stratification, Jig bed physically cut at desired horizontal particle density plant to separate the desired product. Investigation shows that optimum bed height is required at different Jig feed quality to achieve desired product quality, maximum separation efficiency and Fe recovery. This Paper will illustrate role of granulometry and Bed height control on Jigging plant performance.

Jan 1, 2014

By J. Y. P. Leite

In a small-scale mining in Brazil?s northeast, scheelite were exploited since 1940?s using a traditional gravity concentration flowchart (composed by jigs and shacking tables) that operates with low efficient for fine particles. Tailing of this plant was submitted to chemical, mineralogical and size characterization. Results pointed 50% smaller than 74µm with a grade of 0.11% WO3. The particle?s size is an important operational variable to heighten recuperation by shacking tables. Tests using Falcon SB40 centrifuge concentrators and shacking table were realized, optimizing their operational variables. Based on the tests results a new flowchart was proposed for concentrating and tailings recovery.

Sep 1, 2012

By Herman D. Mendoza

A rapid recovery/recycling process was introduced utilizing the surface-chemical properties of finely dispersed mercury and alumina (Al2O3) fibers in aqueous environment. The conventional method of amalgamation or .ball milling. involves the mixing of a substantial amount of mercury to collect free gold during the grinding stage. In effect, a portion of the mercury is transformed into minute droplets that readily float and disperse in the amalgamation effluent. The fine droplets of mercury in the dispersion readily attached onto the positively charged macroscopic alumina fibers (i.e. = pH 9.8) at conditions pH 3 to 10. When an effluent from settling procedure after an amalgamation-grinding stage is passed through a column-bed packed with alumina fibers, maximum collection of negatively charged finely dispersed mercury occurred at pH 3 to 6. The collection/attachment efficiency was 99.5%. The collected droplets of mercury, which are left in the column-bed of alumina fibers, were subsequently rinsed with alkaline solution at pH 10 to 11.5. At these conditions, both mercury and alumina fibers carry negative surface potentials and resulted in the partial detachment of mercury from the alumina fibers. The detachment efficiency was only 30-35%. The attachment/detachment mechanisms in this study were analyzed using the DLVO theory.

Jan 1, 2003

By G. J. Mei

Separation of hematite and iron-containing silicate gangue - aegirine by Flotation using fatty acid collector and (NH4)2SiF6 depressant was investigated in this paper. The flotation tests with single minerals show Ammonium hexafluorosilicate (AHFS) is a selective depressant for aegirine in hematite flotation in weakly acidic medium, which can strongly reduce the flotation recovery of aegirine in the pH range of 4~5 while has no evident effect on the flotation of hematite. The results of flotation tests with actual ores show the separation of hematite from aegirine gangue by forth flotation was possible, and good selectivity was achieved. Chemisorptions were observed on aegirine mineral surface treated by AHFS solution by using SEM and IR spectrum measurements. On the basis of coordination chemistry, a comprehensive mechanism, which reasonably explains the selective depression of AHFS for iron-containing silicate, is also proposed.

Jan 1, 2014

By B. Vasanthakumar

In this study, the effect of adaptation of B.subtilis to sphalerite and galena with respect to the selective flotation of sphalerite from the sphalerite-galena synthetic mixture has been examined. The changes in the surface charge of the mineral and the bacterium, cell wall components and the profiles of secreted proteins are discussed. The flotation recovery of galena increases with the increase in the adaptation cycle of B.subtilis to sphalerite and galena, while the flotation recovery of sphalerite is independent of the adaptation cycle with either mineral. From the gel electrophoresis analysis, the protein profile for the unadapted and adapted cells is found to differ distinctly and this may be attributed to varying molecular weight fractions arising from different growth conditions. Electrokinetic measurements showed shifts in the iso-electric points of not only B.subtilis but also of the chosen minerals after adaptation. Additionally, the zeta potential of B.subtilis is found to become less negative after bacterial adaptation to the chosen sulfide minerals, while it showed an increase in the magnitude of surface negative charge after various enzymatic treatments. The change in the surface morphology and cell wall components such as phosphate, uronic acid and acetylated sugars of the bacterial species during adaptation to sphalerite and galena has been assessed. Selective flotation tests on a synthetic mixture of galena and sphalerite confirm that sphalerite can be preferentially floated from galena in the presence of the insoluble fraction of lysed B.subtilis cells initially adapted to sphalerite, with a high selectivity index. Keywords: bioflotation, b.subtilis, mineral adaptation, sphalerite, galena

Sep 1, 2012

By Chi Zhang, Junyi Wu

"With the increasing popularity of lithium cobalt oxide in lithium ion battery industry, which is driven by new energy vehicle and mobile device applications, the demand of cobalt is also growing rapidly in recent years. There is a significant trend of increasing investment on cobalt capacity in China, and the automation renovation is considered as an option of improving production efficiency. This study aimed at evaluating the practicability of stainless permanent cathode blank and automatic stripping process in cobalt electrowinning process. The purpose is to replace the old starter sheet process in cobalt electrowinning, which so far was used by most of cobalt refineries in China, but very labor intensive and exposed operators to serious aerosols that contained both cobalt and acid. In the old starter sheet process, the initial cobalt starter sheet is produced onto a plate made of titanium, while the titanium cathode blank and hanger bar fit the critical corrosive environment but is lack of mechanical strength for automatic production which has been mature in copper electrowinning process. To evaluate the proper materials instead of titanium, the coupon corrosion tests with different raw materials including 316L and other stainless steel grades were held for several months in production environment at a cobalt tank house in China. Following the comparison between titanium and other tested materials, a pilot production test in a cobalt tank house is also on-going.INTRODUCTION Cobalt has been known in early China and used in pottery glazes, and the ancient Greeks and Romans used its compounds to make colored glass since long time ago. The blue on the colored porcelain from the Tang Dynasty in China was also due to the presence of cobalt compounds. The word cobalt is known being derived from the German kobalt, from kobold meaning ""goblin"", because the cobalt-bearing blue ore, CoAsS, was called kobaltin in Europe in the Middle Ages, it may have been thought to be harmful to the health of the miners because of arsenic in the ores."

Jan 1, 2018

By Roberto Galery, Priscila Esteves, Braz Cardoso, Marcelo Stopa

"It was developed in this work a computational tool to aid in anomaly detection present in the operation of ball mills. The tool uses a torque estimator that is based on measurements taken exclusively in the drive motor. The ball mill equipment widely used in the mining industry has, inherent to its principle of operation, high energy consumption and low efficiency. These characteristics are accentuated when the mill operates outside the ideal conditions of velocity and loading. Direct measurement of these variables is extremely difficult because it requires the installation of sensors in moving parts of the mill. Thus, systems that can help monitoring the operating conditions and predict anomalies are useful because they contribute to improving the performance of the process, help to reduce the energetic consumption, wear on the mill surface and frequency of maintenance shutdowns. The detection strategy implemented in this work is based on the fact that operational anomalies such as an inadequate percentage of balls and incorrect angular velocity manifest itself as a change in spectral components of the torque signal in the mill driven by an electric motor. The mill torque was estimated by processing motor variables measured by sensors commonly used for control purpose and installed exclusively in the motor. The mill was operated at various fault operating conditions and signals from electric motor and vibration on the mill shaft were measured. The spectral components present in the estimated torque signal were then compared with signals from a vibration sensor in order to establishing a correlation with anomalous operation condition of the mill. The experimental results showed that the signals obtained has an excellent correlation with other variables obtained by direct measurement and have potential to be used to construct a system for automatic fault detection in the operation of ball mills."

Jan 1, 2014

By L. S. Gertsch

The production of minerals for human use at locations other than the Earth is expected to ?advance ? human prosperity in ? ways that [do] not compromise the potential prosperity and quality of life of future generations? (Brundtland, 1987); in other words, sustainably. This paper examines the interaction of extra-terrestrial mineral production (ETMP) with the following sustainability imperatives: ? The sustainability of human activities on Earth; ? The sustainability of human activities elsewhere; ? Human survival in general, the ultimate sustainability goal. Some of the consequences of mineral production on Earth are widely considered to decrease the future prosperity and quality of human life. Examples include noxious by-products or wastes and unsettling economic up- and downswings. Moving mineral production activities to extra-terrestrial locations, where appropriate, will decrease many of its deleterious effects. Terrestrial mineral production presently is decreasing in some countries and increasing in others, moving from the cheaper and easier ores to more expensive, difficult materials. When the full costs of maintaining the terrestrial environment in a sustainable manner are included, total mineral pro-duction costs must increase. The cost of extracting mineral products from extra-terrestrial sources will be substantially higher, especially in the initial phases, but as the full costs of terrestrial production increase, at some point in the future (different points for different minerals), the curves will cross (Fig.1). This will occur at different points for different materials, a process whose prediction will be complicated by substitution of cheaper materials for some uses as prices of the original material rise. In summary, mineral products from extra-terrestrial sources will tend to increase the sustainability of human civilization, once steady state has been reached.

Jan 1, 2014

By Sonia Helle, Ursula E. D. Kelm

"From a metallurgical point of view, acid leaching of oxide zone copper ore is considered in the first place in terms of ore grade, whole rock mineralogy, rock granulometry, crushed aggregate size distribution, porosity, permeability and corresponding fluid flow characteristics. Despite exhaustive physicochemical and general mineralogical characterization, drops in copper recovery occur and are often attributed to and “unquantified mineralogical misbehaviour” of the gangue phases. This study establishes an experimental link to monitor and quantify the chemical interaction of chrysocolla, malachite and atacamite with reactive gangue phases.Laboratory-scale sulphuric acid (15%) leaching in small columns is carried out using a synthetic rock composed of 57% quartz, 1% ore phase, and 42% reactive gangue. Gangue phases were selected to represent mineralogy found in argillic, advanced argillic, and propylitic alteration zones. Exotic copper ores of Codelco Norte (in particular Mina Sur) served as model for the modal distribution of mineral phases. Natural reactive gangue phases (<200 Tyler mesh) were chosen as pure as possible: Saz-1 and Swy-1 montmorillonites, KGa-1B and KGa-2 kaolinites (all Clay Mineral Society, USA, Source Clays) Nau-2 nontronite, Imt-1 illite (both Clay Mineral Society Special Clays) and Chilean mordenite, laumontite and bentonite. Ore phases are: mineraloid chrysocolla from Radomiro Tomic (Codelco Norte), reagent grade malachite and a purpose synthesized atacamite-paratacamite mixture. Complete chemical, physicochemical and mineralogical characterizations were carried out for ore and gangue phases.The following observations hold for samples with and without mineralization: Smectite-rich gangue increased up to 75% in volume. Once wet, air-filled vesicles formed due to the rapid sealing effect of overlying smectite in the column. No volume change occurred for illite, mordenite and kaolinite gangues. For kaolinite mixtures acid puddles formed on top of the column during initial leaching due to the delamination and barrier formation of this phyllosilicate. Fluid recovery was <60% for expandable phases and reached up to 80% for non-expandable mixtures. These observations confirm the very low extractions obtained in ore with a combined smectite – kaolinite gangue for Mina Sur. The most important mineralogical changes observed in the solid residues are: reduction of basal smectite phase reflections (XRD), and slight loss of illite intensities. This is also reflected in the major element composition of the residues, which demonstrate a loss of Mg, Mn, Ca, Na, K followed by Fe, Al and Si; with their proportions depending on the starting materials. Furthermore, alunogen and meta-alunogen formed, with related phases coquimbite (illite) and godichite (nontronite) also depending on gangue mineral chemistry. For laumontite samples, meta-alunogen and alunogen precipitated from the leachate."

Jan 1, 2003

By M. Zolghadri

MIBC and sodium metasilicate are used as a frother and a dispersant in coal flotation respectively. In order to study interaction between them, flotation experiments were performed on fine coal (<150 microns). It was found that if the frother (MIBC) dosage is in excess of a certain limit, it has an activation effect on the gangue minerals associated with coal. In addition, it was found that however sodium metasilicate can disperse clay slimes eliminating slime coating, but in the case of excess dosage, could intensify activation effect of MIBC, which is undesirable in coal flotation. Keywords: coal flotation, sodium silicate, frother, dispersion, activation

Sep 1, 2012

By Jens Markowski

The EU Directive 2000/53/EC on end-of life vehicles (ELVs) states that in 2015 at least 85 wt.-% of a vehicle has to be reused or recycled. This result in the obligatory need to separate additionally metallic and other components of the automotive shredder residues (ASR), so that they can be professionally prepared for recycling and reuse further. Currently the iron-containing fines of ASR are deposited as it is not possible to process in blast furnaces due to its particle size (< 4 mm), composition and material properties. Additionally problems are also caused in handling and transportation (dust) of the material. This work focuses mainly on the ASR materials utilization in blast furnaces. Material was further separated into two consecutive fractions by carrying out repeated crushing and magnetic separation twice. The two fractions have significantly higher iron content (up to 75 wt.-%) compared to the initial material mixture. The materials were assessed for their usage in blast furnaces based on the possible pelletisation with and without binders, stability of pellets, shape and size of pellets, etc. Pelletisation of the material was carried out with a single mould pellet press. Further lignite coal was added to the mixture as additive which improved the pelletisation behavior and the mechanical stability of pellets. Lignite coal was chosen as a reducing agent in the blast furnace process contributing towards additional savings in energy supplied. The experiments reveal that the production of pellets from iron-containing fines is possible with a lignite coal admixture of about 15 wt.-%. These pellets displayed good mechanical stability and can be used in blast furnace processes in recovery of the recyclable metals which are currently not recycled. The recycling of not yet recyclable metals would reduce the deposition and can be easily adopted into the economic cycle by their utilization. Keywords: Automotive shredder residue (ASR), FE-fines, pelletisation

Sep 1, 2012

By R. Singh

The paper presents the results of characterization and beneficiation studies carried out on a lean grade tungsten ore sample from Degana, India. Basically, three different routes, involving gravity separation, magnetic separation, and froth flotation were studied for concentration of the sample by physical and physico-chemical methods. Considering the low recovery by physical methods, efforts were put in to produce a tungsten concentrate by physical methods suitable for subsequent hydrometallurgical recovery of tungsten as ammonium para-tungstate. This strategy proved quite helpful in minimizing the losses of tungsten in tailings. Based upon these studies a novel integrated technological process flow-sheet was developed for the exploitation of lean grade tungsten ore deposit of Degana, India. Keywords: lean tungsten ore, characterization, beneficiation, gravity and magnetic separation, hydrometallurgical extraction, integrated process route

Sep 1, 2012

By N. I. Um

The coal bottom ash generated from coal-fired power plant accounted for approximately 5 mil-lion tons in Korea. Almost all of coal bottom ash was treated as reclamation of the landfill because of the content of unburned carbon. For recycling of coal bottom ash, effective removal of that is required. So, in this study, the removal of unburned carbon by flotation was studied with respect to adsorption ability in surface of a bubble in order to consider its application to recycle the coal bottom ash. The sample A, B and C were that the coal bottom ash contained 2.73%, 7.01% and 10.49% of the unburned carbon (UC) respectively. The column flotation was carried out for each time as the artificial injection of air at 10.0L/min flow rate and the reagents of 500g/ton kerosene and 80g/ton MIBC were used. The samples per water of 1.3 liters were from 0.5% to 4% (w/w.%). In the result of this study, the kinetic curves of unburned carbon adsorption from injected air bubbles were in-creased rapidly as equilibrium was approached; only 5 sec was needed from the sample A and B and 10 sec was from sample C. And the equilibrium isotherms of unburned carbon adsorbed by the infected air bubble from the sample B and C could appear the BET adsorption isotherm; MT = KMEEO/(EO-E)[EO+(K-1)E](K: adsorption affinity), but not the sample A that was not enough to express the adsorption curve.

Jan 1, 2014

By A. K. Mukherjee

In this apparatus closed sized particles are placed in a container and then fluidized by passing water through the load of particles. Water flow is adjusted to deposit particles in one or more layers depending on the specific gravity of each of the particles, after which the deposited particles are separated in portions of different specific gravity. The obtained portions represent different ore content of the closed sized fraction. The process is repeated for all other size fractions to generate washability curve of the feed. Three different types of iron ores and one coal sample are tested in this equipment. The theoretical yield-grade curve generated for iron ore feed is unique in absence of any such practice for ore minerals. Similar curve is generated for coal and it is compared with washability curve, an existing practice followed worldwide. This comparison validates the performance of the process and the equipment.

Sep 1, 2012

By U. S. Chattopadhyay

The estimated requirement of the nation by the year 2020 is approx. 80 Mt of steel and more than 0.2 million MW installed capacity of the electricity, thereby increasing the consumption of the coking and non-coking coal, which is expected to be in tune of about 75 Mt & 500 Mt respectively. One of the major deleterious factors in achieving the goal is the deteriorating quality of the feed coal used in both steel and power industries. Indian coking coals, in general, are typified by high ash, high inert (both organic and inorganic), low rank, low reactive macerals content, heterogeneous petrographic make-up, inferior coking properties and poor amenability to washing, thereby necessitating suitable washing measure. Coke-based steel industries in India require washed coking coal containing ash % varying between 17-19. The situation demands taking on immediate challenges to fill up the gap between the requirements and supply of coking coal. This paper reviews the R&D attempts in this laboratory and throws light on the key measures as long-term solution to the problem. Search for alternative source of coking coal, like LVC coal and their judicious preparation technology. The low volatile coking coal (LVCC) constitutes about 50% of the total coking coal reserves in India. These coals are characterized by high raw coal ash content (37 to 40%) and very difficult washability potential. If these coals are treated in the existing washeries, which are generally 2 or 3-product systems, the cost of clean coal is high as the byproduct sale value is low. It has been proposed to produce a new type of by product, which enjoys high demand and good coking properties.

Sep 1, 2012

By Gurubasayya Swamy

This paper presents the performance study of sag mill in the processing of gold ore. Deterioting ore grade and high demand of metals has tremendously influenced the SAG mills. Today?s high capacity Semi-autogenous grinding (SAG) mills expand vast amounts of energy and in doing so consume tons of shell liners and steel balls, while processing ore. Semi-autogenous (SAG) mill performance is influenced by ball charge, feed properties, shell, grate, and pulp lifter design. In the performance study of SAG mill, based on the results obtained it can be observed that SAG mill performed better at feed size +4 inch and grinding media consumption 0.90kg/mt. In the present study the effect of crusher bypass on SAG mill performance, an immediate drop of throughput ranging from 10-20tph is observed. Keywords: sag mill, pulp lifters, grinding media, energy, consumption, throughput

Sep 1, 2012