Search Documents

By O. Kökkilic

This study covers the tests to develop separation process for production of clay and colemanite rich concentrates, and aims to serve the clay and colemanite concentrates extracted from the tailing dams to the industrial applications. For this purpose, samples from the tailing dams in Kestelek Boron Plant (Turkey) with an average B2O3 content of 8%~11 % were subjected to the investigations. The separation process of hydrocyclone--to make clear the way to obtain either clean clay or cole-manite--was initially discussed. Therefore, following the gentle scrubbing (to keep the bimodal size distribution between clay and colemanite) of the tailings to disperse the slurry, two alternative multistage hydrocyclone processes; allowing to recycling the overflows or underflows to concentrate clay and colemanite were respectively tested. As a result of the preliminary tests, the multistage hydrocyclone separation in direction to the clean colemanite concentrates (recycling the underflows) gave the better separation efficiencies. So, all the parameters such as apex and vortex finder diameters and feeding pressures were examined with the multistage hydrocyclone process allowing the recycling the underflows. The detailed multistage hydrocyclone separation process of the tailing dam wastes yielded with colemanite concentrates (approx. 12 % of the feed, w/w) with B2O3 content of 35.0 % and the clay concentrates (approx. 42 % of the feed, w/w) with B2O3 content of 2.1 %. Colemanite concentrates were found good enough either to re-feed in to the separation process or to keep upgrading for final product ready to use in Industry whereas the attempts on production of light bricks from clay concentrates has failed. But it is worth to point out that these clay concentrates can be used for agricultural purposes just in the form as it is.

Jan 1, 2014

By Klaus M. Hahn, Hermann Wotruba, Bernd G. Friedrich

"Due to an increasing demand for nickel and cobalt and the depletion of nickel sulphide deposits worldwide, the production of ferronickel from lateritic nickel ores becomes more significant. About 60 percent of nickel reserves are present in laterite deposits. Common production methods like acid leaching or smelting operations implicate high material and energy consumption. Physical processing methods are also not efficient, because of the fine microstructural intergrowth of the minerals carrying valuable elements such as nickel and cobalt. Due to the high energy consumption of metallurgical treatment of lateritic nickel ore (nickel grade: 0.8 - 3.0%, Co: 0.05 - 0.15%), the separation of waste material (about 75 - 85%) before the metallurgical treatment is desirable. Therefore, an alternative process has been developed, combining a pyro-metallurgical pre-treatment with selected mechanical processing methods. The developed process consisted of a selective pre-reduction and non-selective segregation of the contained metal phases in the first stage. By this, the properties of the metal carrying minerals were changed and could become subject to concentration by means of fine beneficiation processes afterwards. The parameters of the pre-reduction and segregation were varied and the pre-treated samples were examined concerning their efficiency of metalization grade and metal grain size. This paper describes the investigation of pre-treatment methods of a lateritic nickel ore. The pre-treatment and possible subsequent separation methods were examined with regard to the recovery of the valuable elements. Metalization grade was around 80% for both Ni and Co with metal phase grain sizes below 20 µm. Scanning electron microscopy revealed distribution of new metal phases not only on the reducing agent, but also on the “slag” material.INTRODUCTION Nickel laterites are characterized as strongly weathered regoliths with several zones containing reserves of nickel (Ni) and cobalt (Co). These laterites are formed on serpentinites and ultramafic rocks under climatic and/or tectonic conditions that have changed over time (Butt & Cluzel, 2013). The formation of Ni laterites is influenced by numerous geological and environmental factors. In general, there are three ore types named according to the dominant Ni hosting minerals: oxides, hydrous magnesia (Mg) silicates and clay silicates (Butt & Cluzel, 2013). The most Ni laterite deposits contain two of these ore types, usually an oxide zone and an either clay or Mg silicate zone. Distribution of these principal deposit types, their average Ni-bearing phases and mean Ni grade are shown in Table 1. A schematic profile of the different deposits based on the development on serpentized ultramafic rocks is given in Figure 1 (Butt & Cluzel, 2013)."

Jan 1, 2018

By K. D’Elia, L. D. Ogrel, O. A. Malyshev, T. I. Yushina, I. M. Petrov

"The purpose of this research is to develop enhancements in the mineral processing by flotation methods of nonferrous ores. Currently, 180-190 million tons of ore are processed by flotation in Russia. The annual processing volume of copper-nickel and copper-zinc ores exceeds 20 million tons. In the total volume of processed ores by flotation, non-ferrous ores account for roughly 35% and ores of precious metals for another 15%. The total demand of flotation reagents in Russia in 2016 was estimated at 170,000 tons. Sulfur-based collectors used in the flotation of non-ferrous sulfide ores (typically, xanthates) do not always offer sufficiently high recovery of valuable components.It has been found that reagents like DMIPEC and DK-80 improve the recovery of metals into concentrates. To identify the reasons of that higher recovery, quantum chemical calculations of the mechanism and interaction forces of DMIPEC with non-ferrous sulfides were undertaken by determining the stabilization energy of the resulting chemical complexes. It has been shown that, in the interaction of DMIPEC and DK-80 with the surfaces of sulfide minerals, ethylene and acetylene bonds act as the reaction centers, and the formation of molecular p-complexes is the result of metal-cation interactions with the surface and the flotation reagents.In the flotation of non-ferrous ores, DMIPEC and DK-80 act as selective supplementary collectors with foaming properties, and at a flow rate of 3-35 g/ton, they reduce the flotation time, and increase copper recovery by up to 3.5%, zinc recovery by up to 12%, gold recovery by up to 8-10%, allowing to increase the recovery of valuable components by 1.5-12.0%, basically this kind of reagents nearly double the flotation rate, improve the grade of the concentrate, improve the stability of the flotation process parameters, and reduce the environmental impact of flotation plants."

Jan 1, 2018

By Jacek Kolacz

A new sensor based sorting system related to complex image analysis has been developed at Comex AS - Norway. It makes it possible to separate different mineral particles regarding their color, shape, texture, size, density and indirectly their composition. The sorting system has been successfully tested and applied for sorting minerals providing high separation efficiency in the range of 95-99.9 %. The main advantage of this system is connected with its universality where many material parameters are analyzed in the same processing unit by a single passage.

Sep 1, 2012

By Jaime Sepúlveda

"A broad diversity of critical operating conditions may influence, in very convoluted ways, the actual performance of any given mineral processing system, to the extent that it becomes nearly impossible to empirically determine the independent, decoupled impact of each condition. An effective approach to better understand the behaviour of such complex systems is via the extensive use of sufficiently detailed and reliable mathematical models, allowing the process analyst to explore and learn about the independent effect of all relevant operational conditions. Certainly, these tasks are greatly facilitated if the appropriate software tools - such as the Moly-Cop Tools software package - are readily available. Moly-Cop Tools 3.0 is a set of 63 easy-to-use EXCEL spreadsheets designed to help process engineers characterize and evaluate the operating efficiency of any given grinding circuit, following standardized methodologies and widely accepted evaluation criteria. Moly-Cop Tools 3.0 covers conventional and semiautogenous mills, crushers, HPGR’s, rod mills and vertimills, with the corresponding mass balance and parameter estimation routines; plus complementary spreadsheets regarding Bond’s Law calculations, grinding media selection and performance evaluations and other useful utility functions. As a relevant example of application, specifically focusing on semiautogenous grinding operations, the current publication describes how the models can help us learn and rationalise critical empirical observations such as the relationship between feed particle size and optimal ball filling, the role of the rocks as autogenous grinding media as well as the impact of feed size and discharge grate opening on the mill grinding capacity. Over the last 20 years, Moly-Cop Tools has gained wide acceptance around the mineral processing community in recognition to the quality of the mathematical models contained, their simplicity of application and ease of sharing of the calculations amongst all interested parties, since it is available free-of-charge with no restrictions to make as many copies as needed."

Jan 1, 2014

By Ibrahim Alp, Ersin Yazici, Oktay Celep, Haci Deveci

Low extractions (<80%) in cyanide leaching impose the application of physical and chemical pre-treatment methods (e.g., ultra-fine grinding, roasting, alkaline leaching) prior to cyanide leaching to achieve acceptable recoveries. The effectiveness of the selected pre-treatment method is linked intimately with inherent mineralogical properties of ore. In this study, a refractory silver ore assaying 145 g/t Ag was subjected to various pretreatment tests in an attempt to eliminate its refractoriness. Direct cyanidation of the ground ore (d80: 65 µm) produced a low silver extraction of only 29.5% over 24 h indicating its high refractoriness. Previous studies have shown that silver occurs mainly as Sb/As containing sulfide minerals such as pyrargyrite (Ag3SbS3), tetrahedrite (Cu12Sb4S13) and proustite (Ag3AsS3), which do not respond well to cyanide leaching. Also, silver-containing minerals are closely associated with and/or encapsulated in other mineral phases that can restrict the contact of cyanide with silver. Therefore, alkaline leaching (using 3 M of Na2S, NaOH or KOH solution) and ultra-fine grinding as pre-treatment methods were tested to improve the extraction of silver. All the alkaline leaching tests were carried out for 3 h at800C. Neither NaOH nor KOH leaching produced the desired effect on the extraction of silver (i.e., ~30%). Even, a sharp decrease in the extraction of silver (i.e., 10%) was observed in Na2S leaching. On the other hand, ultra-fine grinding (UFG) (d80: 3 µm) substantially improved the extraction of silver in cyanide leaching (95% Ag at 24 h after UFG). It can be inferred from these findings that the refractoriness of the ore is essentially physical in character (i.e. the encapsulation of silver presumably in non-sulphide minerals such as barite and quartz).

Jan 1, 2014

By Takaaki Wajima

The slag was attempted to be converted into the adsorbent for phosphate removal from aqueous solution using the alkali fusion method. The slag was mixed with NaOH powder (NaOH / Slag = 1.6), and then the mixture was heated at 600 ? for 6 h to prepare the precursor. The precursor was stirred at room temperature in distilled water to synthesize the adsorbent, and the removal ability of the obtained adsorbent for phosphate from aqueous solution was investigated. The products, including hydrocalumite and calcite, were synthesized, and the removal efficiencies of the adsorbent for F- and PO43- showed higher than those of raw BF slag, especially removal of PO43- are excellent (99 %), while the removal of Cl- , SO42-, NO3- and Br- was minor. The adsorbent could remove PO43- selectively in the co-existing solution of Cl-, NO3-, F-, SO42- and Br-.The equilibrium adsorption capacity of the adsorbent for PO43- was extrapolated using Langmuir and Freundlich models, and experimental data are found to fit Langmuir than Freundlich. The calculated maximum adsorption capacity of the adsorbent for PO43- is higher than other adsorbent reported previously. The high affinity of the adsorbent for PO43- in aqueous solution was caused by the formation of hydroxyapatite [Ca5(PO4)3(OH)] and brushite [CaHPO4?2H2O]. The prepared adsorbent is expected to be anew inorganic adsorbent for the removal of phosphate ion from wastewater. Keywords: Blast furnace slag, Alkali fusion, Phosphate removal, High selectivity

Sep 1, 2012

By Jacqueline Satur, Yoshiaki Kon, Buenaventurada Calabia, Xiao Sheng Yang, Arvo Naumanen, Kenzo Sanematsu, Sayaka Morita, Tetsuichi Takagi

Granite ores are composed of silicate minerals and a variety of valuable REE (rare earth elements)-bearing minerals, however the processing technique to recover these valuable minerals is not yet developed. In this study, the recovery of REE-bearing minerals by dry magnetic separation and wet high intensity magnetic separation (WHIMS)-settling from surface sample and from drill core sample, respectively, of a granitic REE-Zr-Nb ore deposit was investigated. The two samples have different mineralogy however in both samples, light REE are commonly contained in REE carbonate minerals while Y and heavy REE are commonly contained in zirconium silicate minerals and pyrochlore. The liberation size of the REE-bearing minerals in the two samples ranges from 10-250 ?m. Previous flotation testwork conducted on the drill core sample reported high recoveries of La2O3 (88%) and Ce2O3 (88%) but low recoveries of Y2O3 (42%), ZrO2 (17%), and Nb2O5 (29%). The objective of this study was to obtain higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling. Both processes implemented the application of a low magnetic intensity to initially separate the ferromagnetic minerals then a high magnetic intensity to recover the REE-bearing minerals. The results showed higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling indicating the potential of magnetic separation and gravity separation in recovering the heavy REE-bearing minerals. WHIMS-settling is more recommendable than dry magnetic separation because of its applicability in treating a wider range of particle size. In the WHIMS-settling, the light REE, Y, and Zr minerals were recovered mainly by applying four stages at high magnetic intensity of 21,500 gauss while the weakly magnetic pyrochlore was recovered mainly by decantation of the nonmagnetic slurry after a short settling time of 0.25 to 0.50 h. (MAX.300 words)

Jan 1, 2014

By Paulo Castillo, Cesar Gomez, Jaime Alvarez

Operations using flotation to produce mineral concentrates require testing of frothers to characterize their ability to preserve bubble formation size and to build a stable froth. Many techniques have been proposed to measure parameters associated with these two roles. These techniques focus, in general, on only one of these roles and are based on special equipment operated at conditions quite different from those existing in industrial cells and columns. Both roles have been simultaneously characterized in a laboratory flotation column, but the requirements associated with the installation and operation of one of these units, are a serious limitation for its use on-site. A technique based on the use of a laboratory mechanical cell, a common piece of equipment in operations, will have wider application. Establishing the ability of a frother to control coalescence by preserving bubble formation size is done through bubble size measurements as a function of frother concentration. Froth build-up and stabilization is associated with the amount of water carried by bubbles into the froth layer, which has been demonstrated to correlate with the gas holdup in the collection zone. Procedures devised for determining the critical coalescence concentration (CCC) from measurements of bubble size as a function of frother concentration, and the gas holdup by collection of water displaced from the cell by the presence of bubbles at different frother concentrations, were tested. Three analytical-grade frothers were utilized: a straight-chain (1-heptanol) and a branched (MIBC) alcohol and a polyglycol (PPG425). The results obtained at a standard set of conditions, demonstrated consistent differences between these frothers, and the ranking from least to most effective for reducing bubble size or decreasing water drainage followed the same sequences found when more complex frother characterization techniques are used.

Jan 1, 2014

By Y. M. Zhao

Reutilization of waste printed circuit boards (PCB) can not only prevent potential environmental pollution, but also achieve recycling of secondary resources. Study on recycling of discarded PCB belongs to the front edge of environmental pollution prevention and resource recycling. In order to effectively crushing waste PCB, and solve the problem of secondary pollution of fugitive odor and dust during the crushing process, a wet impacting crusher was adopted to achieve comminution liberation of PCB in water medium. 96.79% of the crushed yield was distributed in ?2mm, and metal took 97.18% in this grade of production. Size distribution of PCB particles was characterized double peaks at the sizes of ?1+0.5mm and ?0.074mm. A double Rosin-Rammler function, is called DRR function, is put forward to describe the size distribution of PCB particles. The DRR function of cumulative weight percentage oversize of PCB was non-liner fitted by self-defining DRR function of the Origin 7.0. The evaluation indexes of the fitting results are the correlation coefficients R2 of 0.9994 and residual E of 0.18671, those show that DRR function is perfectly accurate. Based on the research the mechanical separation and material properties of PCB, a wet process of reclaiming metals from PCB using a new style separator ? tapered diameter separation bed (TDSB) in water medium was designed, and the related separation mechanism was studied. The fluid field of the tapered diameter separation equipment was simulated by the Ansys Flotran software, the variation laws of the velocity in each position in the fluid field as well as the equation of axial distribution sectional max velocity were analysed according to the simulation result, the stress change and motion trajectory of the pellet in the certain fluid field were analysed. The results show that the expanding tubular structure of the varied diameter separation bed indicates gradually decreasing velocity of water flow along the axis, assuming a certain angle in the bed, as a result of the gravity?s influence, and there was corresponding change to the distribution of the flow velocity, thus the whole formed a special fluid field where velocity variations exist in different positions. When the material passed through the fluid field along with the water flow, as a result of the difference to the particle density, the granularity and the shape, there would appear the difference to the motion trajectory as well as the movement distance under the action of the fluid: The lower density materials discharge along with water flow, but the higher density materials would be kept in bottom of the bed and discharge through material mouth. Therefore, light and heavy products were separated effectively according to the density. Using tapered diameter separation bed to process the ?1mm size crushed material of waste printed circuit boards, with the discharge of water 5.5m3/h, feed-rate of the material 250g/min and with an obliquity 35°, product with 93.92% in integration efficiency and 93.73% in recovery ratio of the metal were obtained by the primary separation. Compared with other mechanical methods, the range of particle size was broaden using the TDSB to recovery metals from PCB, and lower limit size of separation almost approach to 0. An innovative process of ?wet impact crushing+ classifying+ tapered diameter separation? recycling metals from waste PCB was developed.

Jan 1, 2014

By Markus A. Reuter, Albert Scholte, Ewoud V. Verhoef, Gerard P. J. Dijkema

A dynamic, interactive map has been developed of the life cycle of a number of metals, from mining through to minerals processing, metal production, product manufacturing, recovery and waste management. Whilst the existing metal process network and waste management infrastructure provide substantial scope for (product) design, these also limit change due to the complex interdependence of metals, both in production and recovery, and the strong path dependency of industry and infrastructure development. Therefore, models for dynamic simulation were constructed that allow the specification and evaluation of the metal process network and waste management infrastructure ‘products’ over a longer time span. The model has been constructed using a bottom-up approach, to enable assessment of the environmental aspects of metallurgy and to simulate changes in the system structure and technology, i.e. from reactor or individual process step up to integrated material cycles. The model comprises hierarchical mass balances and linear models of individual processes and sub-processes. Thus, at lower system aggregate levels an increasing level of technical detail is represented. Data reconciliation has been used literature data on process feed, products and residue composition to calculate representative and reliable split factors around each (sub-)process. World production figures on process capacity and recovery rates are be used to calculate the relative contribution of processes. The dynamic map is illustrated with a case on the introduction of lead-free solder.

Jan 1, 2003

By Linghu Changjin

Based on the characteristics of typical marine sedimentary phosphate rock in Guizhou, Southwest China, together with the research findings made on the surface electric properties of pure collophanites taken from different areas in pure water and under the action of collectors, a pure minerals flotation test of collophanite was conducted in this research. The differences of collophanite flotation behavior and the effects of the different pH values, varieties, and dosage of collector on flotation separation of collophanite were studied. It is suggested that that in pure water, collophanite had a negative charge within a wide pH range. The electro negativity values of collophanite increased with the addition of collectors GJBW and WF-01. When GJBW and WF-01 were used as collectors, the collophanite was depressed in acid medium, but had a good flotability in basic medium.

Sep 1, 2012

By T. V. Chnyrenkova, J. Troncoso, V. A. Luganov, G. P. Kluev

"Arsenic-gold bearing ores are used as flux in smelting or are leached out with extraction of gold. For decreasing arsenic content in processed materials and for breaking up the lattice and opening up of gold the raw materials are roasted. Some regularity was established for sulfidizing of arsenic bearing compounds in a presence of pyrite and for oxidation of ores and concentrates in the presence of soda.This article analyses the results of laboratory and pilot testing of dissociating and oxidizing roasting of gold-arsenic bearing concentrates. During the dissociation roasting under vacuum arsenic is sublimated into elemental and sulfide forms. This process allows minimizing the negative influence on the environment but requires costly engineering solutions. Roasting in a limited quantity of oxygen in the gaseous phase makes it possible to sublimate arsenic in the form of oxides and sulfides and may be carried out in fluid bed furnaces."

Jan 1, 2003

By S. I. Anufrieva, N. A. Permyakova, E. G. Likhnikeevich

"Russia’s rare metal reserves are composed of compositionally and structurally complex ores and are characterized by an increased content of natural radionuclides due to their geochemical similarity with rare metals. For instance, concentrates of Zashikhinsky daeposit are characterized by an increased content of uranium (0,06%) and thorium (0,59%); Beloziminsky deposit holds pyrochlore-apatite-magnetite-carbonate ores characterized by increased radioactivity (130 mkR/h) and containing 0,0016-0,0025% of uranium; Etykinsky deposit is characterized by columbite-pyrochlore-microlith mineralization with an average ore grade of 0,013% of uranium and 0,0020% of thorium; eudialyte concentrate of Lovozero deposit (Alluaiv area) belongs to Class II of mineral reserves. Industrial development of these mineral reserves involves the need to comply with environmental standards, public health requirements applicable to finished core and by-products, to take into account the amount and class of the generated radioactive waste, the possibility of disposal or recycling of the radioactive production waste. Concentration processes of radioactive rare metal feeds most often lead to a concentration of natural radionuclides and their accumulation in concentrates. Comprehensive hydrometallurgical processes are currently under development for such concentrates, aimed at producing salable products compliant with the radiation safety standards. The choice of the hydrometallurgical processing method for radioactive rare metal concentrates is based on the mineralogical component of the concentrate, textural and structural features, the distribution of valuable components and impurities, and the content of radionuclides. A systemic approach to the selection of processing methods, in particular integrating several methods, is an effective solution. Methods may not only be combined, but also inextricably linked with each other. Hydrometallurgical processing methods include leaching by acidic and alkaline agents; sulfatization for selectively decomposing the minerals and moving the bulk of U and Th into solution; fluorine extraction process. Methods of precipitation and co-precipitation, extraction (by liquid and solid extractants), sorption, and ion exchange are used to decontaminate the solutions by removing thorium, mezathorium, uranium, and their radioactive decay products. Agents used in hydrometallurgical processing of radioactive rare metal ores include sulfuric, nitric, hydrochloric, hydrofluoric acid, alkali (NaOH, KOH), sorbents (for example, AB-17) for sorption of uranium and extractants (mono- and bidentate organophosphorus compounds, diamides, etc.) for the extraction separation of rare, rare-earth, and radioactive elements."

Jan 1, 2018

By Song Z. Guo

Calcite and magnesite are both carbonate minerals and their crystals belong to trigonal system. Flotation tests were carried out to investigate the flotation behaviors of calcite and magnesite. The test results show that the floatability of calcite and magnesite under different grinding environment had obvious differences. The floatability of calcite using sodium oleate as collector after dry grinding is better than wet grinding, but the floatability of magnesite after wet grinding is better than dry grinding. The XPS surface elements test and zeta potential measurement show that, wet and dry grinding process makes the distribution difference of surface anion and metal cation, then influence the floatability of the two carbonate minerals using sodium oleate as collector. Difference of the carbonate crystal structure and solubility properties was also investigated. Research shows that crystal structure difference of calcite and magnesite causes the difference of solubility, which can influence the flotation behaviors under different grinding environment. Keywords: carbonate mineral, crystal structure, solubility properties, flotation, surface character

Sep 1, 2012

By Sushanta Majumder

The physico-chemical characteristics of raw materials used for the production of iron ore pellets have a strong influence on the productivity of pelletization operations and on the quality of pellets. Since iron ores from different sources are used for making iron ore pellets and since the quality of the ores varies with time, there is a need to optimize and control pellet plant operations on a regular basis to achieve optimum productivity while maintaining pellet quality within the desirable specifications. In order to achieve this objective, a model-based on-line optimization system was implemented on two industrial scale induration furnaces. The optimization system consists of a rigorous mathematical model of the induration process, a model for the permeability of the bed of pellets, a statistical model for the quality of iron ore pellets and an optimization module based on sequential quadratic programming. The rigorous model is tested on-line using the wind-box temperature available real-time. The process was optimized to enhance induration furnace productivity for the given constraints on pellet quality parameters such as the cold compressive strength (CCS) and Tumble Index (TI), and other equipment design parameters. Process variables such as induration machine speed, cold air flow rate and hood temperature profile were used as the optimization variables. The on-line optimization system was successfully implemented in two industrial induration furnaces and lead to enhanced productivity. Details of the on-line optimization system and results of process optimization will be presented.

Sep 1, 2012

By Thomas Pretz, Alexandra Pehlken

Sampling of municipal solid waste is known to be difficult to sample if it has to be representative. When dealing with municipal solid waste, the usual method is to study separately waste material below 40 mm and particles bigger than 40 mm. The material < 40 mm cannot be sorted manual and is termed the “fine fraction”. The particles > 40 mm can be separated manually and are usually sorted into pre-defined groups of materials. These groups can be defined depending on the demand of quality assurance. But standardisation of procedures is not far progressed, even for the widely practised sorting methods.

Jan 1, 2003

High flotation of iron sulfide minerals at high pH values in copper ores is mainly due to the activation of these minerals by copper species dissolved from copper sulfide minerals during grinding. Several methods have been tested to reduce this copper activation during grinding and therefore to depress iron sulfide flotation. They include grinding the minerals at high pH values or with a less reactive medium such as high chrome, and addition of a thiol collector or copper complexant during grinding. The efficacy of these methods in the flotation of a copper ore was tested against more common methods of depression of iron sulfide flotation. The mechanism of iron sulfide depression in these methods was also investigated.

Jan 1, 2014

By F. O. Milovich, V. A. Ignatkina, L. A. Samatova, E. D. Shepeta

"The aim of the research was to increase technological parameters of the flotation of finely disseminated scheelitecarbonate ore using selective reagent regime.In the studies the monomineral fractions of scheelite and calcite; samples of the scheelite-carbonate ore of the Primorsky deposit with the range of the carbonate module 3-65 were used. A carbonate module of ore is the ratio an initial assay of calcite to an initial assay of scheelite. Sodium oleate, iso-decyl alcohol, water glass, calcium chloride, soda or sodium hydroxide as flotation reagents were used. The flotation method in the Hallimond tube and in a mechanical cell, an adsorption method for study the kinetics of adsorption of oleate and isodecyl alcohol and its combinations on scheelite and calcite, IR spectroscopy including ATR to study the composition of surfacecompounds were applied. Selective reagent regime may include two ways - a combination of collectors or a modification of depressants of calcite and other gangue minerals. On one hand the combination of sodium oleate and higher fatty iso-alcohols of fractions C12-C16 in the rough scheelite flotation to reduce the flotation activity of calcite has been studied. On the other hand depression of calcite flotation by calcium chloride with water glass into rough flotation was used; modified the steaming cycle by Petrov's method applying change the concentration of water glass and other. Fatty iso-alcohols can adsorb on the surface of the calcite that reducing the adsorption of sodium oleate and floatability of calcite has been fallen. Their co-adsorbing with oleat on the scheelite surface were support the hydrophobization and flocculation of slime particles of scheelite. Flocculation of the particles of scheelite leads to increased up 3 times of the recovery of scheelite from the slime class, and calcite change up only 1.4-1.1 times it’s recovery.The growth of the carbonate module more than 11 is decreased the assay of WO3 in the scheelite concentrate of selection cycle."

Jan 1, 2018

By Bisweswar Das, Barada Mishra, Hrushikesh Sahoo, Swagat Rath

Banded hematite jasper (BHJ) containing 45.2% Fe, 32.64% SiO2, 0.63 % Al2O3 and 1.25 % LOI is found difficult to beneficiate either by magnetic or flotation techniques due to fine intergrowth of jasper with hematite. Phase transformation by reduction roasting with activated charcoal followed by low intensity magnetic separation to achieve a suitable iron concentrate has been attempted in this study. The mineralogy of the ore and different roasted products has been studied by X-ray powder diffraction (XRD) and scanning electron microscope (SEM) to understand the reduction mechanism. The magnetite formation is observed at 850ºC while metallic iron appeared at a higher temperature. The effects of reduction variables such as reduction time (30-270 min), temperature (750-1050ºC), and reductant (1-12 %) using activated charcoal are studied. An iron concentrate with 64.65% Fe and 55.8% recovery could be obtained under optimum conditions of temperature: 850ºC, time: 1.5 h, and reductant: 6% by weight.

Jan 1, 2014