Search Documents

By Lev Filippov, Lorène Dessalas, Inna Filippova, Yves Foucquet

"Seafloor massive sulphide (SMS) deposits, similar in composition and genesis to terrestrial volcanogenic massive sulphide deposits, are generally found in volcanic seafloor environments along major rifts and mid-ocean ridges. Theyare associated to extensional tectonic settings such as nascent-arc, rifted-arc and back-arc environments. They may represent important source of base metals and be an alternative to on-land resources. Seafloor massive sulphide deposits have particular mineralogical compositions and textural features differentiating them from terrestrial one. When extracted from salty water and exposed to the ambient air, massive sulphide samples strongly oxidize and soon become covered by thin layers of iron, copper and zinc rich sulphates and oxides, as well as elemental sulphur. The textural properties vary according to the degree of maturity and the sample position within the hydrothermal deposit. The total porosity of that type of samples is also relatively high, especially for immature samples such as black smoker chimneys, which can reach 15% of total porosity. Because the secondary mineralization and porosity level are different, seafloor massive sulphides ores respond differently from terrestrial ore to processing methods. Froth flotation, commonly applied to separate all type of sulphides from the gangue, is one possible technique for processing seafloor ore. Sulphide recovery rate is, in most cases, excellent (>90%) however separation of the various mineral phases is difficult to obtain even when applying known methods used for terrestrial ore. Moreover, the flotation behaviour decreases drastically with the time of conservation at the surface, even when the samples were stored in a confined environment. High pH values, which is a good way to depress pyrite and therefore to favour the flotation of copper and zinc sulphides, do not have the same effect on seafloor ore. Consequently, careful flotation procedure must be elaborated to obtain efficient mineral separation technique for this specific marine ores."

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 P. Fawell, C. Castillo, C. Ihle

"The need to reduce fresh water consumption has pushed many Chilean mining companies to utilize seawater obtained from distant locations. At the same time, increasing amounts of fine particles in copper tailings raise new operational challenges, in particular, the thickening and transport of tailings featuring significant fine fractions, which are predominantly clays. In the present paper, we study the role of salinity – using seawater and NaCl – on the flocculation efficiency of copper sulphide tailings to which kaolinite was added. To mimic the water recovery stage in thickeners, flocculation has been induced in jar tests and the corresponding aggregate size distribution has been estimated from chord length distribution data obtained using a focused beam reflectance measurement (FBRM) probe, at various mean turbulence intensities. Results show that for constant flocculant dosing, a measurable influence of the salt on the resulting aggregation exists. For each case, resulting optimal turbulence levels are also reported, a particularly interesting feature when comparing flocculation efficiency of the coarse and fine fraction. INTRODUCTION The concentration of copper minerals through comminution and flotation is intensive in the use of fresh water. The need to reduce the consumption of fresh water and the environmental standards associated with increasingly demanding mining operations have driven improvements in the techniques of recovering water from tailings. The challenges are even greater when required to treat minerals with high clay contents. In Chile, kaolinite is one of the most important clays to consider due to its abundance in the tailings from many operations. The most common and highest throughput unit operation in the mining industry for the recovery of water from tailings is gravity thickening, with sedimentation of fine particles assisted by flocculation. Flocculation is the process of forming aggregates by contacting the suspended particles with a flocculant. The flocculant is typically a water-soluble synthetic long-chain polymer, where copolymers of acrylamide and sodium acrylate are the most common types used in the Chilean mining industry. The aggregation mechanism includes the following key steps: (1) flocculant distribution through the suspended particles, (2) flocculant adsorption onto particle surfaces, and (3) collisions between particles leading to polymer bridging to form aggregates, but concurrently (4) breakage of aggregates becomes a factor under prolonged shear (Gregory, 1988)."

Jan 1, 2018

By Willis Forsling, Prabhakar Swarna, Hanumantha Rao Kota

The solubility of wollastonite and its Hallimond flotation behavior as a function of dodecylamine concentration and pH are examined. The flotation response is characterized by adsorption and surface energy in the presence of amine. The methods of UV-Visible and FT-IR spectroscopy for adsorption and sessile-drop contact angle for surface energy estimation are employed. The results of wollastonite dissolution clearly showed its non uniform dissolution. The surfaces are depleted with calcium ions and became rich in silicon within 10 min of flotation time. Maximum flotation of wollastonite corresponds to a half monolayer coverage of amine, which is substantiated by the surface energy parameters. A good correlation between flotation, adsorption and surface energy as a function of amine concentration and pH was observed. The sudden increase in wollastonite flotation and amine adsorption at and above 5x10-5 M initial amine concentration is thought to be due to two-dimensional precipitation of amine on surface in accordance with the recent 2D-3D precipitation model of amine adsorption on silicate minerals.

Jan 1, 2003

By Leming Ou, Longsheng Yi, Qiming Feng, Yiping Lu, Qing Shi, Kun Liu, Guofan Zhang, Yanfei Chen

"Three important components of stirred tanks involved in energy consumption, the impellers and baffles, were investigated to intensify the agitation pretreatment on the flotation of nickel ores. Flotation tests revealed that the stirred tanks with two impellers had an advantage over those with one impeller in intensifying agitation pretreatment, and the higher agitation speed led to better flotation performance of nickel ores. Installation and removal of baffles were also employed in the stirred tanks, and flotation tests demonstrated that with baffles, the flotation grade increased significantly. These agitator design improvements were used to demonstrate that the energy supplied to the system significantly influences the flotation recovery and that if the energy consumption of the agitation pretreatment is ideal, flotation efficiency can be improved. Data from full-scale operations backed up these results.INTRODUCTIONThe flotation recovery of nickel-copper sulphide ore at the Western China nickel mine has historically been difficult due to the presence of large amounts of serpentine minerals (Feng, et al., 2012). Many studies reported that serpentine minerals tend to have a positive potential at pH values up to 9.5, while sulphides (such as pentlandite and chalcopyrite) have a low isoelectric point(Feng, et al., 2012). Serpentine minerals can form surface coatings on negatively charged sulphides surface due to electrostatic attraction when they interact with each other, which may also reduce collector adsorption and increase the hydrophilicity of the sulphide particles. In order to improve the flotation of nickel sulphides, sodium hexametaphosphate, sodium silicate, carboxymethyl cellulose (CMC), and other agents are used to disperse serpentine coating from sulphide surfaces in the flotation of the Jinchuan deposit and other nickel ores in China ( Kirjavainen and Heiskanen, 2007; Lu, et al., 2011). However, it is difficult to improve of the sulphide flotation due to the high dosage and the lack of selectivity."

Jan 1, 2018

By Yuexin Han, Jie Liu, Shuai Yuan, Yanjun Li

"In order to improve recovery efficiency of iron minerals from iron ore tailings and to reduce its connected environmental pollution, this article investigated the reducing roasting of iron ore tailing in a laboratory fluidized magnetization roasting reactor to optimize the roasting method and conditions. The examined parameters included roasting temperature, roasting time and reducing atmosphere. The parameters evaluating magnetizing roast efficiency and theoretical value were determined. X-ray diffraction (XRD) analysis was used to investigate the conversion of iron phase after roasting. The results show that the best magnetizing roast conditions are roasting temperature of 540?, holding time of 15min, and CO concentration of 20%. The magnetization conversion ratio of roasting products is over 80%, under the best magnetic separation condition, the concentrate grade of iron is 65.61 % and the recovery of iron is 83.77 %. The XRD analysis shows that Fe exists in hematite and siderite before roasting and exists in magnetite after roasting. The technique not only recovers the iron minerals from tailings with good economic benefit, but also reduces the environmental pollution of tailings accumulation.INTRODUCTION Iron ore tailings are the solid wastes generated during the beneficiation process of iron ore concentration and are one of the main pollution concerns in the mining industry (Das et al., 1996). Continuous development of the iron and steel industry has led to the increasing amount of iron ore tailings; there are over 300 million tons of iron ore tailings discharged per year (Rao et al., 2016). The huge amount of stockpiled iron ore tailings brings a series of environmental and social problems. Comprehensive utilization of iron ore tailings can not only reduce environmental load but also conserve resources, promoting sustainable development of the society. In recent years, iron ore tailings as secondary resources have received considerable attention in many countries in the word and numbers of studies on utilization of iron ore tailings were carried out, such as recycling the valuable minerals (Datta et al., 1996; Jia et al., 2013; Panda et al., 2018), used in construction material compositions as alternative source of raw materials (Das et al., 2012; Zhou et al., 2012; Luo et al., 2016) and other utilization. The iron minerals were recovery by magnetization roasting (Rao et al., 2016; Yang et al., 2013; Yang et al., 2011) and flotation (Kumar and Mandre, 2016). By comparison the reduction roasting has more advantages, but it was found that the conventional roasting equipment was inefficient, high energy consumption and un-economically applied on an industrial-scale."

Jan 1, 2018

By V. I. Ryaboy, V. P. Kretov, S. E. Levkovets, I. V. Ryaboy

"Using the flotation of a gold-containing ore from a deposit in Kazakhstan as an example, we have conducted a study designing dialkyldithiophosphate collectors, in addition to xanthates, for the flotation of hard-toenrich gold-containing ores to increase gold recovery.The increased flotational ability of the dialkyldithiophosphates was determined by their surface activity at the liquid-gas interface and their hydrophobic ability, the changing of which allowed us to control the collecting power and selective ability of the dialkyldithiophosphates. The studying of the surface activity of aqueous solutions was done using the stalagmometric method and the evaluation of the hydrophobic ability was done in percentage of the relative value of the zinc ion binding in the solution in standard conditions.Studying the influence of surface activity in our designed dialkyldithiophosphate collectors, with their close hydrophobic ability, showed that even with a small increase in surface activity in their aqueous solutions, gold recovery increased by 2-3% in laboratory conditions. Using this enabled us first to apply the dialkyldithiophosphate collector BTF-161 at a plant in Kazakhstan, and then to introduce the specially designed dialkyldithiophosphate collector BTF-163, which has been in use since. Further study of dialkyldithiophosphate activity based on this concept showed us that for the range of short-chain dialkyldithiophosphate collectors with a chain length of up to ?5, the effectiveness of ore processing became lower the higher their surface activity got, with relatively small differences in their hydrophobic ability. For long-chain dialkyldithiophosphates with a chain length of over ?5, ore processing effectiveness increased with the increase of their hydrophobic ability.Based on these studies, a new effective dialkyldithiophosphate collector, BTF-1517, was designed. Using this reagent in continuous gold recovery tests allowed us to reach an 84.21% recovery with a concentrate quality of 15.66 g/t, while using the applied collector BTF-163 in similar conditions led to the recovery of 82.87% with a concentrate quality of 15.65%. As a result, the Kazakhstan processing plant decided to conduct industrial tests with the BTF-1517 collector."

Jan 1, 2018

By Güven Önal, Gülay Bulut, Mustafa Özer, Yunus Emre Benkli, Olgaç Kangal, Mustafa Tarkan

There are various types of natural zeolite deposits in Turkey. Naturally occurring zeolites are excluded from many important commercial applications where uniformity and purity are essential. In this paper, the beneficiation of natural zeolite, taken from western part of Turkey, was investigated. According to X-Ray Diffraction (XRD) and mineralogical studies carried out on the representative ore sample, the natural zeolite was found to be in the forms of clinoptilolite and heulandite. Clinoptilolite forms as a devitrification product of volcanic glass in tuffs. Quartz, clay minerals, orthoclase, plagioclase, biotite, seruzite-muskovite and epidote were observed as impurities. Several types of mineral processing methods were performed in order to remove impurities from the natural zeolite sample to produce high purity zeolite. Gravity separation methods such as shaking table and superpanner were carried out for separating heavy minerals, while high intensity dry magnetic separation was used for discarding magnetic minerals.

Jan 1, 2003

By E. V. Bratygin, E. G. Dmitrieva

The aim of the research was to study the thermodynamic characteristics of high-temperature processing of ilmenite concentrate deposits "Central" in a neutral and oxidizing atmosphere, as well as its interaction with alkaline additives. The research was conducted using a scanning colonoscopy on thermogravimetrical analyzer NETZSCH STA 449 F3. A sample of the test material weighing 10 mg was placed in a crucible and heated at a rate of 10 °C/min to 1200 °C in argon or air. Studies have been conducted pure ilmenite concentrate and its mixtures with 5 % and 12.5% of sodium carbonate. The results of the analysis of the thermogravimetric curves it was found that the recovery of the concentrate carbon will come from ulvospinel, not pseudobrookite, and the reaction recovery is possible at temperatures above 900°C. While removing produced in the decay ilmenorutile of iron oxides in an inactive form, for example, iron (III) oxide, it is possible to reduce the quantity of the solution of ilmenite formed during the restoration of the melt anosovite. The analysis of data obtained during heating of ilmenite concentrate with sodium carbonate in concentrations of 5 and 12.5% transition pseudobrookite in ulvospinel is missing, it just breaks down into hematite and titanium oxide, which, in turn, react with N?2??3. It should be noted that increasing the concentration of sodium carbonate in the sample contributes to more complete interaction of iron oxides and N?2??3 with formation of ferrites of sodium. This can ensure full recovery of iron oxides in the concentrate, which is part of secondary ilmenite can not be dissolved in the melt formed by the lower oxides of titanium. In addition, the increase in the content of soda in the mixture significantly reduces the temperature of the initial melting point of the slag and facilitates the coagulation of metallic iron.The obtained results were used for laboratory studies of the solid-phase sintering of briquettes from ilmenite concentrate with additives of sodium carbonate and a reducing – coal, as well as for the development of technological mode of solid-phase sintering of the concentrate with the aim of obtaining product recovery with a titanium dioxide content of more than 75 %.

Jan 1, 2018

By T. X. Hu

Pyrite ore is one of the main raw materials in the production of sulfuric acid. For a long time, the raw material containing the pyrite, which is used to produce sulfuric acid, generally contains S only 32%~45%. A plenty of residue from the sulfuric acid production contains 40%~50% Fe and 1%~2% S. Some of the residue also contains Cu, Pb, Zn and other harmful elements like As, thus it pollutes environment seriously and is solid waste. The research on comprehensive utilization of the residue has been made by many scholars. Through the study, the residue can only be used to pro-duce iron concentrate and the iron oxide red pigment. But because of the complex techniques, the low recovery, the low grade of iron concentrate , high sulfur in iron concentrate, causing second waste residue and the environmental pollution, the residue is mainly used as an accessory material in the production of cement, and is of a low value. Therefore, the iron resource in pyrite has not been used efficiently until now. In the paper, the flotation condition test, the flotation open circuit test and the flotation closed circuit test to produce high-purity pyrite concentrate with the low-grade pyrite ore in oceanic ore deposit have been carried on. Flotation reagent scheme of sulfuric acid used as activator and butyl xanthate as collector is determined. After four times depth cleaning, high-purity pyrite concentrate containing 52.82% S, 44.29% Fe, and only 2.89% impurities has been obtained. The S recovery is 99.13%, and the Fe recovery is 96.00% in the high-purity pyrite concentrate. The oxidizing roasting depth desulfurization experiment of the high-purity pyrite concentrate has been conducted. The results show that the Fe grade in the residue obtained is 68.58%, the content of S is 0.25%, the content of P is 0.0084%, the content of As is 0.0065%. The residue is a kind of high-quality iron-smelting raw material. Based on the above experiments, the industrial experiments on producing high-purity pyrite concentrate with the low-grade pyrite ore, and producing sulfuric acid and iron concentrate with high-purity pyrite concentrate have been done. The results indicate that the high-purity pyrite concentrate with the S grade of 51.24%, the Fe grade of 44.15% has been obtained. The iron concentrate obtained with 65.73% Fe and 0.23% S is a sort of high-quality iron-smelting raw material applied to the production of steel and iron smelting. Through the experimental study, the sulfur and iron resources in the pyrite ore have been recovered and utilized efficiently.

Jan 1, 2014

By Venugopal Tammishetti

One of the important technological challenges facing the iron ore industry in India is to find commercially viable technologies to process alumina rich iron ore fines and slimes. The key to solving this problem lies in developing selective reagents for the separation of iron oxide minerals from associated gangue minerals like quartz, gibbsite, kaolinite and montmorillonite. We present in this paper our successful results on the dispersion-flocculation of three different natural iron ore slime samples from mines in India using the reagent combination of PVP dispersant and corn starch flocculent. All the three samples contained hematite, goethite, kaolinite and gibbsite minerals as confirmed by X-Ray Diffraction (XRD) analysis. The effect of various process parameters such as pH, dosage of reagents, settling time and pulp density was studied. We were able to produce a concentrate assaying 66.2% Fe and <2% Al with a yield of 67.4% by weight (with a recovery of 77% of iron values) using PVP (1 ppm dosage) and corn starch (20 ppm) for one of the slime sample (Sample I) assaying 58.2% iron (Fe) and 3.8% aluminium (Al). The XRD analysis of settled and dispersed fractions revealed that alumina-containing minerals like clay and gibbsite mostly remain in the dispersed phase while iron-bearing minerals tend to concentrate in the flocculated fraction. Keywords: iron ore, slime, flocculation, dispersion, beneficiation, starch, polyvinylpyrrolidone

Sep 1, 2012

By Jacek Kolacz

"Comex has carried out an extensive research work related to optimising sensor based sorting systems. The main target was to achieve efficient separation and maintain high capacity of the process. Eventually, the operating cost of the sorting process was investigated in terms of potential industrial applications and possible replacement of the existing traditional processing equipment. The study included an influence of the following factors on the separation efficiency: capacity, particle size and distribution, particle shape, material properties like colour, density and composition, as well as percentage of the rejected fraction. The above factors were also considered in the calculation models for the operating cost of the sorting process. In addition, other elements were considered like compressed air cost, cost of energy, labour cost, and necessary service and maintenance cost. All these elements were implemented into the calculation model allowing quick and effective evaluation of the major parameters for sorting applications. Finally, the study was carried out for two popular sorting principles: visible light sorting utilising differences in color, texture and shape and X-ray sorting using differences in density and chemical composition. GENERAL INFORMATION ABOUT SORTING POSSIBILITIES Application of the sensor based sorting systems, without any doubt, brings a lot of possible advantages in many mineral operations. The main advantage of the new system is related to its universality and at the same time very sophisticated image processing functions, which can be carried out in the same processing unit (Kolacz, 2014). Figure 1 shows the CXR-1000 system from Comex with 1 m belt width, in the configuration where many different analysed parameters can be used to provide particle separation. The image analysis system includes a camera installed either over the transport belt conveyor or at its discharge end. The system includes the X-ray attenuation analysis realized by the XRT system in the central part of the conveyor belt. The sorting system can be used with both optical and XRT analysis or separately depending on an application."

Jan 1, 2018

By Liu Jie

Refractory iron ore deposits in China have various genesis and complicated types, the nature of which is poor, fine-disseminated and complex. Therefore, refractory iron ore could scarcely be separated and utilized by traditional mineral processing technology at present. It is necessary to explore deep reduction technology to change the characteristics of refractory iron ore and to use effectively the iron resource. And deep reduction technology is that on the condition of higher reduction temperature than that of magnetic roasting and stronger reducing atmosphere, the iron oxides from iron ore was reduced to metallic iron particle that is easy to dissociate. And then production from deep reduction is easily separated by magnetic separation and iron powder production was obtained finally. Deep reduction technology for Lingyang iron ore from Jilin, China, as the refractory iron ore, was studied in this paper. The influences of such main factors as reduction temperature, time and coal content were investigated. The results showed that the Metallization rate of reduction product was up to more than 90% under optimum conditions, and then higher iron grade and recovery of reduction iron powder were obtained from subsequent magnetic separation. Furthermore, the deep reduction mechanism in the system was studied by the means of XRD and SEM analysis for reduction production and Physical Chemistry of Metallurgy. Analytical results indicated that during deep reduction, the size of iron particle from deep reduction materials was increasing as reduction temperature rising and reduction time extending. The growth of metallic iron particle from deep reduction production was divided into such three stages as reduction nucleation, deep reduction and growth of metallic iron particle.

Sep 1, 2012

By V. F. Petrov

Today, sodium cyanide is extensively used for extracting gold, however it is highly toxic to the environment if not managed properly. This paper discusses the key challenges presented to gold operations in efforts to come into alignment with the Russian environmental regulations and suggests solutions to overcome these challenges. It is a fact that the major environmental threat cyanide poses to water sources. Therefore, natural water sources should be well protected from the adverse effect of cyanides used in hydrometallurgical processes. For this, the following site procedures and facilities are practiced: in-site and external water recycling systems, reclaim water treatment if required and tailings ponds with water impermeable screens (tailings ponds with controlled leakage). Cost comparison analysis of cyanide destruction methods was carried out. It was revealed that the aldehyde treatment method developed by Irgiredmet JSC demonstrated the best economics. Cyanide emissions are treated by mass-manufactured packed and membrane devices which allow to keep cyanides at the acceptable limiting values established by environmental regulatory agencies.

Jan 1, 2014

By Bent Babel, Martin Rudolph

"The characterization of reagent-mineral interactions in flotation systems of finely intergrown ores holds difficult challenges for the applicability of standard techniques like Hallimond tube tests and contact angle experiments or renders them impossible due to a lack of sufficient samples in terms of quality and quantity. This disadvantage may not apply to more sophisticated techniques, but these often do not work in an aqueous environment. We present the utilization of an atomic force microscope with a hydrophobic colloidal probe to characterize the wettabilities of individual mineral domains of an ore sample, while additional spectral information is gathered by Raman spectroscopy. The exemplary ore sample investigated is mainly containing cassiterite and quartz, therefore the reference measurements like Hallimond tube tests and contact angle experiments were carried out with this binary system as a comparison. The focus of the study lies in the correlation of data gathered by the atomic force microscope and the Raman spectrometer with data from standard techniques. Finally, the applicability of the colloidal probe atomic force microcopy technique for reagent-mineral investigations is critically evaluated.INTRODUCTIONThe focus of this paper is the application of colloidal probe atomic force microscopy (CP-AFM) for theinvestigation of reagent-mineral interactions on a binary system of cassiterite and quartz. This and similar concepts using hydrophobic AFM probes have been applied by multiple authors (Rudolph and Peuker, 2014a; Rudolph and Peuker, 2014b; Wada et al., 2017; Xie et al., 2017). The hydrophobic interaction is the main interacting mechanism for the hydrophobic colloidal probe with hydrophobic sample surfaces and the long range attractive component has been accounted to nanobubbles on the interacting surfaces (Yakubov et al., 2000). More detailed information on nanobubbles are available in two reviews compiled by Attard and Hampton (Attard, 2003; Hampton and Nguyen, 2010). This paper is based on the work by Rudolph and Peuker comparing different AFM based measuring concepts, additionally gathering data with Raman spectroscopy and correlating results of microflotation and CPAFM measurements (Rudolph and Peuker, 2014a; Rudolph and Peuker, 2014b)."

Jan 1, 2018

By S. Gaydardzhiev

Initial experiments towards preparation of hollow ceramic microtubes by dip-coating of fibrous plants with water based alumina gel-casting slurries using hemp and coconut fibres as templates have been done. It has been found that the wettability of fibres and accordingly the stability of the developed ceramic layer on their surface during slurry gelation varied significantly within the different fibre types. Good correlation between the diameters of the template fibres and the resulting channels has been found at the level of solids loadings used, 31 %. Hemp fibres used as bundles have led to formation of multi channel patterns while the coconut fibres-templated process resulted in uniform monochannel materials. The micro tubes have show good mechanical handling.

Jan 1, 2014

By Lilong Huang, Yuan Long, Li Shi, Guowang Zhang, Xiao Xiao

"Graphite is the key raw material of new carbon materials such as graphene and spherical graphite. The size and completeness of graphite flakes directly affect the performance of new carbonaceous materials.The research aims to increase the yield of large flake graphite by way of preventing the flake graphite from being damaged during the grinding process. A series of grinding and flotation studies on the flake graphite samples of Yichang in Hubei Province were carried out by vertical stirred mill . The damage coefficient L characterising the degree of graphite flake fractured and corresponding formula was proposed to determine the quality of the grinding and grinding of the flake graphite. The way the damage coefficient L of graphite flake would be affected if with different mill, different media material and size, stirrer speed were investigated. The test results show that vertical screw stirred mill helps the protection of large flake of graphite as well as the graphite liberation. When grinding to the same fineness, the damage coefficient L of graphite flake is 1.20 for vertical stirred mill, while the damage coefficient is 2.93 for ball mill. Minimum damage coefficient of graphite flake was obtained when using 6 mm polyurethane coated ball as grinding media, under the condition that rotation speed of the stirrer within the range of 100~130r/min. The grade of graphite in the concentrate floated from the ground product was 94.16%, the rate of recovery for graphite was 94.66%, and the content of +0.15mm was 54.83%.1 INTRODUCTION Flake graphite is a very important non-metallic mineral[1,2],and due to its special flake structure, the greater the scale and the higher the C grade, the value of its application is larger too. Therefore, in the grinding of graphite sorting process, We should minimize the destruction of graphite scales.. In this paper, graphite mine in Yichang, Hubei Province was used as the raw material for the study. Rough concentrate with C-grade of 36.49% was prepared by rough grinding and coarse separation. Then a series of grinding and flotation studies on the rough concentrate were carried out by vertical stirred mill , which aims to increase the yield of large flake graphite and to provide technical support for improving the beneficiation process of graphite ore."

Jan 1, 2018

By B. Q. Xiao

In surfactant flooding, surfactants added are often a mixture of the same type of molecules with different lengths of carbon chains. The relationship between a single, pure surfactant solution and crude oil is seldom studied. Additionally, up to now, alkylbenzene sulfonates are applied widely in surfactant flooding, such as Daqing oilfield, China. A factory producing alkylbenzene sulfonates will enlarge its yield to 20 000 tons per year over there. For the purposes of widening the alkylben-zene sulfonates? application, 16 kinds of pure alkylbenzene sulfonates were synthesized through Friedel-Crafts acylation and Wolff-Kishner reduction reactions, and the compounds? molecular structures were confirmed by 1HNMR and 13CNMR spectra. The factors affecting interfacial tension (IFT), such as, surfactant type, oil composition, electrolyte concentration, and alkali concentration were considered. The synthesized pure surfactants? critical micelle concentration (CMC) and optimal salinity were measured through interfacial tension technique. According to lab experiments results, heavy alkylbenzene sulfonate (2SY) was synthesized in magnifying scale in Jinzhou Wash Chemical Plant and the coretests were conducted using it. The results showed that the homemade heavy alkylbenzene sulfonate (2SY) flooding can improve oil displacement efficiency 20% more than water flooding at surfactant?s concentration from 0.05%(wt) to 0.2 %(wt).

Jan 1, 2014

By Kaustubh Joshi, Pradip, Beena Rai, Kesri L. Menaria, Venugopal Tammishetti

"Beneficiation of alumina rich iron ore slimes is a major challenge for the Indian iron ore industry. High alumina is deleterious for the performance of both blast furnace as well as sintering plants. Slimes generally contain 5 - 10% alumina, and hence despite assaying as high as 60% Fe, those are dumped in tailing ponds. The slimes are typically less than 37 microns. Selective flocculation of iron ore slimes using highly selective reagents is thus an option worth exploring. Our research is directed at employing state-of-the-art molecular modeling techniques for the selection/design of selective reagents for this separation. We have earlier reported our results on starch as a selective flocculant for iron ore slimes. In this paper, we present our results on the selective dispersion-flocculation of natural iron ore slimes using guar gum flocculant. With careful selection of various process parameters such as flocculant dosage, dispersant dosage, pH and settling time, we were able to obtain a concentrate assaying >66% Fe and <3.5% Al2O3 with an yield of 65 to 68% (recovery of iron values more than 70%) from a natural iron ore slime sample assaying 58% Fe and 7% Al2O3."

Jan 1, 2014

Mineral flotation is effective over a relatively narrow particle size range of approximately 10 µm to 150 µm. If the upper particle size limit can be increased, however, a run-of-mine ore may be coarse ground, and only the middlings are ground further to achieve required grades. This will result in significant energy savings and increased throughput. In this communication, methods of increasing the upper particle size limit will be discussed on the basis of a flotation model that can predict flotation from both hydrodynamic and surface chemical parameters. An example of increasing flotation recovery by control of a chemistry parameter is given.

Jan 1, 2014