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By Q. Zhang

Phosphate tailings through Flotation contains large amount of dolomite which is difficult to be separated from apatite. In this present research, phosphate tailings is recycled by Flotation i.e. re-processing. High-purity dolomite with purity as high as 91.17% is seperated, which contains 19.82% of MgO. The results of orthogonal test show that the effect of various levels of different factors on the high-purity dolomite floatated. Future utilization of purified dolomite is also discussed: magnesium fertiliser especially magnesium phosphate is expected to be an ideal product from high-purity dolomite.

Jan 1, 2014

By S. M. Viduka

This paper presents a numerical investigation of solid separation in jigging device, which is a gravity separation method widely used in ore processing. Separation is recognized as being heavily dependent on fluid motion in the jig. This study explores the effects of the inlet time dependent velocity profile on jigging performance. Modelling of the liquid-solid system is performed through a combination of computational fluid dynamics (CFD) to simulate liquid flow and discrete element method (DEM) to resolve particle motion. The initial packing conditions consist of a binary-density particle system of 1130 particles each 1 cm in diameter. A variety of jigging profiles are implemented in jigging. The saw tooth pulsation profile is selected with three variations in both amplitude and frequency. The performance of each profile variant is compared in terms of solid flow patterns, separation kinetics, energy, and mean particle position. These quantitative comparisons demonstrate significant differences in the segregation rate, energy, and solid phenomena, helping find an alternative optimum operating setting for the system.

Sep 1, 2012

Flinders Power, formerly NRG Flinders, is considering the possible use of low rank coal from Lake Phillipson, South Australia (SA) in its power stations at Port Augusta, SA. Typically, this coal contains about 35% moisture and 10% ash. Unfortunately, it also contains high levels of sodium (1% Na) and chloride (0.95% Cl) with a Na2O level in ash of 18.9%. Such levels cause serious problems during coal combustion, making the use of as-mined coal impractical for power generation. This paper describes the development of an aqueous leaching technique to remove 90% of the sodium and chloride and to yield a product with a Na2 O level in ash of less than 3%. Small-scale agitation leaching tests with good quality tap water at ambient temperatures showed that the coal needed to be crushed to minus 5.6 mm to obtain maximum removal of water-soluble sodium and chloride in 30 min. Leaching kinetics, but not the ultimate removal of salt, were enhanced by the use of higher temperatures (up to 150°C), but this was deemed uneconomic. Varying the pulp density between 20% and 50% had little effect on extractions and there was no benefit in multiple stage water washing. The best results by water leaching were 69%~74% extraction for sodium and 95%~97% for chloride, meaning that the sodium removal was well below the target level. From SEM examinations of the leached product it was concluded that the remaining sodium was organically bound to the carbon atoms in the coal. Further tests using aqueous solutions containing cation exchange additives such as calcium chloride (CaCl2) or ammonium chloride (NH4Cl) or sulphuric acid (H2SO4) showed that significantly enhanced sodium extractions were possible and target specifications were met. Two options, namely a single-stage and a two-stage leach, were then investigated. In a single-stage leach with additive, minus 5.6 mm coal was leached at 33%~50% solids for 30 min at ambient temperature and then filtered and washed with fresh water. This gave a sodium removal level of about 81% and a Na2O level in ash of about 5%. These levels do not quite meet tar-get specifications. In a two-stage leach, the coal was first leached with water alone without an additive as in the single stage leach, and the washed residue re-leached under similar conditions for about 5 min with an additive (CaCl2), and then filtered and washed. This gave a cumulative sodium removal of 96% and a Na2O level in ash of 1.4%~2.4%. These levels are well within target specifications.

Jan 1, 2014

By E. Szelag

The adsorption and stabilization of mineral dispersed systems by using Pluronic copolymers with different molecular weights and EO content has been studied. The role of sequential adsorption of EO-PO copolymers and cationic surfactant (CTAB) on the carbonate particle properties and in determining the stability of their suspension was studied with particular attention to the conformation of the polymer at the solid-liquid interface. The purpose of this work was to investigate the flocculation phenomena, influence of polymer molecular size on stability of suspensions of magnesite and dolomite and the effect of addition mode of polymer and surfactant. The suspension stability measurements and the determination of sedimentation speed were carried out using an optical analyser (Turbiscan). In most of investigated cases, the biggest floccs and the fastest sedimentation were found for low concentrations of copolymers.

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 Mingfei He, Xianyang Qiu, Hongling Wang, Yude Gao, Qingbo Meng, Xiaoping Xu, Hao Bu, Guosheng Wang

"By the “HGMS-gravity separation-Flotation” combined technology, a Ta-Nb-Sn concentrates with the grades of Ta2O5 10.00%, Nb2O5 9.13% and Sn 42.62% at the recovery of 44.73% , 9.13% and 14.62% respectively , a Li concentrate with Li2O 3.11% at the recovery of 51.83% and a feldspar product are obtained. All the value elements are recovered. INTRODUCTION Tantalum and niobium widely used in electronics, atomic energy, aerospace and chemical industries with the advantages of high melting point, good ductility, low vapor pressure, strong corrosion resistance and high thermal conductivity are important strategic resources which occupy a special position in rare metals (Crockettand, 1993; GAO and Zou, 2004; LI and HUANG, 2012). China's tantalum and niobium resources are poor, and most of them are low grade, fine grain size, complex composition, and polymetallic associated with refractory mineral resources (GAO and Qiu,2013; Liang and Li, 2016). The Yifeng Lion Ore containing lithium and other rare metals (tantalum, niobium and tin) is an important lithium polymetallic deposit in China Jangxi province. While extensive previous studies have settled on the recovery of lithium minerals by flotation only for the extremely low grade of Ta, Nb and Sn. The regular gravity concentration is used, and the recovery of tantalum niobium is low. This paper sets out to investigate a combined flowsheet of “high gradient magnetic separation (HGMS),-gravity separation-flotation” to effectively comprehensively recover the Li, Ta, Nb, Sn and the feldspar resources in the Yifeng Lion Ore.ORE PROPERTIES Chemical analysis The run of mine comes from Jiangxi Yifeng Lion ore. The main elements of the ore chemical analysis results shows in Table 1. From Table 1, the grades of lithium and rubidium are relatively high, but the grades of tantalum and niobium are lower than the industrial grade; feldspar with high content of potassium and sodium and low content of iron can be used as high-quality ceramic raw materials."

Jan 1, 2018

By W. Rubarth

The kaolin losses in hydrocyclone classification are determined by the fines, which are discharged together with the water to the underflow. This paper presents an improved technique of water injection to the conical part of the cyclone applied especially for small cyclones in kaolin preparation. In small hydrocyclones water, injection is a sensitive process. Therefore, the process was stabilized by controlled water injection dependent on the measurement of the underflow shape. Three applications of this innovation are presented. In the first case, the water injection is applied for the separation stage in dilute suspension where the final product is produced in the overflow of a 50mm hydrocyclone. The underflow contains sand and residual kaolin. For a higher kaolin recovery, the underflow is usually treated downstream in washing cyclones. The wash water injection results in a 45 ? 50% - reduction of the kaolin fraction <25µm in the underflow. Thus, water injection to the classifying cyclone leads to a separation comparable with a downstream washing stage. An additional hydrocyclone stage can be deleted. The second application refers to a classification in dense suspension. Here, the underflow of the last hydrocyclone stage was directed to a washing in a 50mm hydrocyclone. The additional injection of 3L/min water in to the conical part of the cyclone reduced the kaolin losses by half.The third application was executed in the washing stage equipped with 75mm hydrocyclones where the underflow is directed to flotation. Using the water injection the kaolin recovery in this stage was increased by approximately 20%. Keywords: hydrocyclone, classification, kaolin beneficiation, water injection, underflow washing

Sep 1, 2012

This article takes the OMRON C200HE PLC for example introducing its application in mica-paper production equipment, including style selection, address assignment of I/O point, and programming for different function. In the transformation process of simulated data and digit data, the corresponding relations between two data and so on are also discussed.

Jan 1, 2014

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 M. Evertsson, K. Bhadani, E. Hulthén, M. Bengtsson

"Modelling and simulations for mineral processing plants have been successful in replicating and predicting predefined scenarios of an operating plant. However, there is a need to explore and increase the potential of such simulations to make them attractive for users. One of the tools to increase the attractiveness of the simulations is through applying optimization schemes. Optimization schemes, applied on mineral processing simulations, can identify non-intuitive solutions for a given problem. The problem definition itself is subjective in nature and is dependent on the purpose of the operating plant. The scope of this paper is to demonstrate two optimization schemes: Multi-Objective Optimization (MOO) using a Genetic Algorithm (GA) and Multi-Disciplinary Optimization (MDO) using an Individual Discipline Feasible (IDF) approach. A two stage coarse comminution plant is used as a case plant to demonstrate the applicability of the two optimization schemes. The two schemes are compared based on the problem formulations, types of result and computation time. Results show that the two optimization schemes are suitable in generating solutions to a defined problem and both schemes can be used together to produce complementary results. INTRODUCTION The comminution process for a mineral processing plant consists of multiple crushing and classification stages and aims to produce fine material to liberate ore from the minerals. The modelling and simulation of such processes are well established using static process models (King, 2001; Napier-Munn et al., 1996). A recent development in the dynamic modelling for such processes has shown further increase in fidelity compared to the static process models (Asbjörnsson, 2015). The developed simulations can be utilized to design, operate and control mineral processing plants based on the requirements of users (Bhadani et al., 2017). Typically, the requirements in the operation of the comminution process are conflicting in nature, as for instance, reduction of power draw by process units, maximization of production of fine materials, and increasing utilization of the process units. These conflicting requirements leads to a Multi-Objective Optimization (MOO) problem to operate a mineral processing plant. The MOO problems are normally referred to as non-linear problems and its fundamental understanding with respect to process behaviour is difficult to achieve."

Jan 1, 2018

By X. Cui

Hydrocyclone is widely used in closed-circuit grinding process. However, in the first classification operation of coarse particles with high pulp density, the shortcomings of traditional cyclone are that the grinding cycle load is much high, the apex of cyclone is easily to be blocked and classification efficiency is less. Specifically, the problems of traditional cyclone used in grinding process are as follows: (1) Mill utilization factor is low and its handling capacity is small. (2) Coarse particles mixing in cyclone overflow affects the following separation process and fine particles mixing in underflow causes over-grinding, which affects the total recovery rate of valuable minerals. (3) High grinding cycle load leads to large amount of high-density slurry pumping, which causes high energy consumption and severe wear of cyclones, pipelines and pumps. The applications of new type pre-classification hydrocyclone with centrifugal volute in the first classification process of Iron Mine Mill are introduced in the paper. Pulp particles fed in the centrifugal volute were arranged in advance, so that coarse particles can be far away from the overflow pipe, which can reduce the short circuit current to avoid coarse particles entering overflow and improve classification efficiency and accuracy of cyclone. The strong points of the new cyclone in the coarse classification operation are as follows: (1) finer overflow and less fine particles mixing in underflow improves classification efficiency more than 10%; (2) lower ball mill load cycle improves ball capacity more than 10%;(3) grinding energy consumption reduces by more than 20% and cyclone feed pump reduces energy consumption by more than 12%. In short, new type pre-classification cyclone with centrifugal volute solves the problems of fine particles mixing in underflow, high grinding cycle load and less classification efficiency in the coarse classification operation. Therefore, it has broad application prospects in ferrous metal and non-ferrous metal ore dressing plant.

Sep 1, 2012

By O. L. Kachor, A. V. Bogdanov

"In 2015 in the frames of federal special-purpose program «National system of chemical and biosafety of Russian Federation (2009-2014)» Federal State Budget Educational Institution of Higher Education ""Irkutsk National Research Technical University” (further–INRTU) performed works aimed at disposal of accumulated arsenical residues at industrial site of the former Angarsk arsenical plant (AAP) processing arsenious ores from Svirsk town in Irkutsk region. The plant in 1934-1949 produced arsenic trioxide for the defence industry. Prior to starting the works on disposal of industrial pollution focus the total amount of cinders stored on 13 ha of industrial site of AAP was 156 900 tons with 1% average arsenic content. Close to the cinders there were also remains of industrial buildings and process equipment in the amount of 6 600 m3 that contained 150 tons of arsenic. Additional source of pollution at the industrial site of AAP is contaminated soil amounted to 48 000 tons. Proven reserves of gold and silver in the cinders were 6.1 and 47 g/t respectively. In 2015 the source of arsenious pollution was detoxificated according to mineral matrix technology and stored in a special landfill with separate stocking of gold-containing cinder and other arsenious residues. This technology of waste disposal specifies extraction of valuable metals from cinder in future. The similar case is with Vershino-Darasunsky settlement in Trans-Baikal Territory where the abandoned industrial site of the former arsenic plant is located in the central part of the settlement. The concentration of arsenic and valuable components can be compared to the concentration at AAP. Since 2016 the demand for removal of such industrial pollution sources is legislated due to amendments in Federal Law No. 7-FZ on environmental protection. It results in a real possibility to remove such dangerous industrial residues deposits as the one located in Vershino-Darasunsky settlement. INTRODUCTION In the frames of federal special-purpose program «National system of chemical and biosafety of Russian Federation (2009-2014)» as well as the Irkutsk region program “Environment protection in Irkutsk region"" for 2006-2015, INRTU performed the works aiming at disposal of accumulated environmental deprivation–arsenical residues from the former Angarsk arsenic plant (further - AAP) (Figure 1) on processing of arsenopyrite ores of Svirsk town in Irkutsk regionThe plant produced arsenic trioxidein 1934-1949."

Jan 1, 2018

As a kind of collector, Xanthates are generally used to make sulfide minerals hydrophobic in flotation process. Xanthate adsorption on a galena surface has been widely studied experimentally. In this paper, DFT methods were employed to investigate the local adsorption interactions about the collectors,such as ethyl xanthate (CH3CH2OCS2?, EO) and ethyl trithiocarbonate (CH3CH2SCS2?, ES), absorbing on two different PbS clusters. From the results, it can be easily found that, on the edge or at the apex, both collectors, with two S atoms bidentate coordinating on the clusters, have surprising interaction energies, while on the surface, its interaction is relatively weak in the form of monodentate ligand. NBO analysis results reveal that there is at least a covalence bond with sulfur atom about 10% and lead atom about 90% when the absorbed lead is on the lattice edge or at apex, but, if the absorbed lead is on the lattice surface, no covalence band would be found. Meanwhile, the S-Pb bond, formed by the absorbed Xanthate and galena lattice, seems to have much more covalence characteristic than that formed in the PbS lattice inner. Furthermore, those data also imply that the difference of the collecting effect between the EO and the ES may be not notable, because of the similar distance and the interaction energy for the same interaction mode.

Jan 1, 2014

Traditional mineral processing techniques are more and more difficult to recover the increasingly low grade phosphate ores today. Although bioleaching method has been attempted to process low grade ores in hydrometallurgical field due to economical and environmental reason, it has been hardly used in leaching phosphate ore at home and abroad. Strains of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans were collected and separated from the acid drainage of a coal mine in Anhui province of China. Ultraviolet irradiation and Microwave inducement were applied to the bacterial cultivation process to produce strains of Acidithiobacillus thiooxidans and Acidithi-obacillus ferrooxidans able to tolerate extremely low pH conditions and generate sulphuric acid by oxidizing elemental sulfur or sulphide and the mutagenesis can achieve higher leaching rate. The bioleaching result will improve more by the addition of Tween series surfactants.

Jan 1, 2014

By S. N. Sahu

Attempt was taken in this study to explore the misplacement phenomena in binary mixture in solid-liquid fluidisation system. The binary mixtures of hematite and quartz particles at different sizes were taken. The closed size range particles were taken to minimize the size and shape effect in fluidization. As both the minerals have appreciable density difference, the separation of both minerals with closed size range has an advantage. The experiments were conducted in different permutation and combination of different sizes of binary mixture to observe the fluidization phenomena. The samples were taken at different heights in fluidized zones and analyzed the distribution of particles of both minerals. The fluidization characteristics were evaluated with respect to operating and design parameters. It has been observed that when the terminal velocity of quartz and hematite particles is same or near to each other, then misplacement is significant. In general, the segregation index value is near to one, complete segregation takes place whereas this value is near to zero, complete mixing takes place. The experimental data were used to find out the segregation index for different size ratios of quartz and hematite particles and the values are within 0-1. When the size ratio is 1 or less, complete segregation takes place whereas this ratio is within 1.0-1.4, partial mixing takes place. Similarly, when the size ratio is within 1.4-2.0, complete mixing takes place whereas this ratio is within 2.0-4.6, then it moves towards complete segregation in inversion manner. Keywords: particulate fluidization, misplacement zone, bed expansion, terminal velocity, mixing characteristics, segregation index

Sep 1, 2012

By Kazutoshi Haga, Ryo Kawarabuki, Atsushi Shibayama, Masato Kosugi, Masanobu Kawata, Refilwe S. Magwaneng, Kohei Mitsuhashi, Altansukh Batnasan

"The recovery of copper and iron from carbonaceous sulfide ore is of economic and environmental interest despite its processing difficulty. Hydrometallurgical methods can be used to concentrate sulfide metals of these hard-to treat ores in a simple and eco-friendly manner. In this study, high pressure acid leaching process was comprehensively studied to dissolve metals from an ore with organic carbon and carbonaceous gangue material using autoclave equipment. The sample used for the experiment was reduced to an average particle size of 75 µm after undergoing flotation to reduce carbonaceous gangue minerals. A comparative study on two leaching reagents of sulfuric acid and iron sulfate and their dosage was used to observe dissolution of copper and iron. Other parameters of temperature (90-170 0C), solid-liquid ratio (1:10, 1:5, 1:3 and 1:1) were investigated through kinetic studies to access the influence of organic carbon and carbonaceous material on recovery of copper and iron. Materials balancing analysis was used to evaluate the efficiency of metal dissolution. The effects of parameters on leaching rate and concentration was demonstrated. Results obtained from the experiment indicated low concentrations of copper and iron in pregnant leached solutions, which was attributed to acid consumption by organic carbon and carbonaceous material in feed. However, the high efficiency rates of 92.4% and 86.3 % for copper and iron respectively in sulfuric acid can be concluded that leaching of concentrates of carbonaceous ore is possible provided system control on type of acid, pH and temperature. The purpose of this research is important in understanding mechanism involved in dissolution of copper and iron in concentrates of carbonaceous ore and marks an improvement in leaching of highly contaminated ores."

Jan 1, 2018

By Raquel Franco de Souza Lima, Isao Matsuoka

"Microflotation studies and abstraction experiments were conducted with synthetic oxide spinels relating to chromite (MgCr2O4, FeCr2O4, FeFe2O4 and FeAl2O4), using sodium oleate as collector. An attempt was done to correlate this data with the speciation of oleate in the bulk solution and at the interface solid-water, to explain the floatability curves. The microflotation tests were conducted using a microflotation cell. The abstraction of sodium oleate was measured at 25°C, with one gram of synthetic spinel and the abstraction time was 30 minutes. After centrifuging, the residual oleate concentration in the supernatant was measured by using the spectrophotometric method described by Mizuniwa et al. (1977), that covers the range from 1.5 to 9 ppm. To cover the range from 0.2 to 1.5 ppm, the residual oleate concentration was measured using the spectrophotometric method described by Gregory (1966). The amount of oleate abstracted was calculated from the difference between initial and residual (equilibrium) concentrations.Figure 1 shows the floatability of FeCr2O4, FeAl2O4, FeFe2O4, MgCr2O4 as a function of pH and sodium oleate concentration of 1 x 10-5 M. The IEP of each sample is indicated in the figure by a vertical line in the horizontal axis. The chromium-bearing spinels FeCr2O4 and MgCr2O4 show the lowest isoelectric points (IEP), around pH 6, while in the case of FeFe2O4 and FeAl2O4, the isoelectric points lie at pH 6.5 and 7.3, respectively. It is seen that the flotation-pH curve for FeFe2O4 has a peak at the pH of the IEP, while flotation peak for FeCr2O4 appears at pH below the IEP and that of MgCr2O4 does at pH above the PZC. On the other hand, FeAl2O4 is floated at pH range between about 4 and 7,3 (IEP). This suggests that the pH value at which the maximum flotation occurs is dependent on the sort of spinel to be floated, though it appears in the vicinity of the respective IEP."

Jan 1, 2003

By G. C. Li

Gold extraction using iodide leaching from refractory carbonaceous gold ores was studied. Thermodynamic analysis of iodide leaching chemistry had been carried out. Eh-pH diagram of Au-I2-I--H2O leaching system showed that the coordinating active forms from iodides were I3- and I-, while the major coordinate compound formed during iodide leaching was AuI-. For leaching parameters optimization, technological parameters such as I2 concentration, I2 :I- ratio, oxidation assisting agents, liquid/solid ratio, and leaching duration were studied. The leaching results showed that the average Au leaching rate reached 91% and 92% for oxidized ore and roasted primary ore respectively. Leaching process proceeded in weekly acidic or neutral slurry at ambient temperature; the leaching duration was 4 hours. After that gold was extracted from the pregnant liquor by activated carbon adsorption ? desorption ? electrowinning process. Gold recovery was over 93% in the adsorption process, while the gold recovery in electrowinning process was about 95%, provided that the initial gold concentration is 40mg/L or larger. For iodine regeneration it is enough to add hydrogen peroxide in excess into the filtrate after gold electrowinning, all the iodides existing in the solution in any forms would be precipitated in the form of elemental iodine.

Jan 1, 2014

By Aziza A. Yousef, Suzan S. Ibrahim, Mahmoud A. Arafa, Mohamed A. Abdel Khalek

In view of the shortage of soft water all over the Middle East countries, seawater may be used to replace the fresh water in flotation beneficiation. The flotation process required about 7 m3 of fresh water/ ton ore. This article aimed to study the effect of seawater cations and anions on the flotation process of four important mineral commodities. The adsorption of collector, zeta-potential, zero point of charge and floatability of pure minerals were studied. The individual effects of different cations and anions that are predominant in seawater, within their more or less actual concentrations were studied on individual mineral and on groups of them. The troublesome Ca2+ and Mg2+ ions, in the anionic circuit could be controlled by soda ash addition to the pulp before the anionic collector. The addition of sodium silicate improved the floatation selectivity of mineral mixtures and natural ore. At the optimum conditions the calcareous phosphate ore yielded a concentrate recovery of 83% with a grade of 34% P2O5, with 0.61%MgO, which from an ore assaying (25.3% P2O5 and 9.4% MgO).

Jan 1, 2003

By Sravya Kosaraju, Christian Ekberg, Stefan Allard

Li-ion batteries are now used in electric vehicles (EVs), plug-in hybrid vehicles (PHEVs) and, hybrid electric vehicles (HEVs). Nanostructured Li(NiyMnzCo1-y-z)O2 is one of the more popular cathode chemistries for automotive Li-ion battery, due to its enhanced properties such as large surface area, short diffusion length, enhanced ionic and electronic conductivity, improved mechanical strength and structural integrity [Pan et al, 2013]. Recycling of Li-ion batteries helps to mitigate environmental effects of virgin metal extractions along with improper disposal of end of life batteries. To fulfill these objectives of the recycling, recovery of pure streams of the involved metals should be considered. In this study, the batteries were first discharged and dismantled in an inert atmosphere (Ar). The electrodes were then heat treated in a box furnace. This was done in order to break the chains of the adhesive (PVDF) and consequently separate the metallic substrates Cu and Al from the electrochemically active compound. This heat-treatment also helped to simplify the dissolution of the metal constituents in the electrochemically active compound from the cathode in the acid leaching process. Solvent extraction was chosen to achieve separation and recovery of metals with higher purity from these leachates. In the scope of the present work, a complete process from the point of dismantling to separation of constituent metals using solvent extraction was studied.

Jan 1, 2014