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By Gjergj Dodbiba, Toyohisa Fujita, Li Pang Wang, Masashi Yamane

"The platinum-group metals (PGMs), are currently receiving worldwide attention as they have major industrial uses. PGMs, i.e. ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt), are widely used as catalysts in petroleum and chemical processes. In addition, they find wide applications in automotive exhaust-gas control converters and are of immense importance to the electronic industry. Broadly speaking, PGMs are extracted in minute quantities from a limited number of ores, found mainly in South Africa and Russia. As the PGMs are both costly and almost indestructible, they are usually recycled from various forms of scrap. In other words, the recycling of the PGMs is an essential factor in the overall management of the PGM economy. In addition, the ever-increasing user areas have created renewed interest in the search for new sources or deposits of PGM, which in turn requires an in-depth knowledge of its characteristics. In this work, the emphasis is placed on the need to analyze the composition and microstructure of blast-furnace slag for recovering PGM metals. In other words, chemical composition, surface analysis and microstructure analysis of the DC arc furnace slag have been carries out. The aim is to provide a detailed analysis of this material for anyone with an interest in gaining further knowledge of its specific content for recovering PGMs."

Jan 1, 2014

By M. L. Wu

A moderately thermophilic acidophiles strain had been isolated from the bio-heap leaching plant in Zijinshan Copper Mine, and the identification based on the PCR-16S rRNA gene sequence homology analysis with morphologic and physiologic methods was conducted by polyphasic taxono-my and phylogeny research. The results show that the strain by depurated belongs to Acidthiobacillus genus and is considered as Acidthiobacillus albertensis.

Jan 1, 2014

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 N. R. Mandre

In the present work an attempt has been made to study beneficiation of low-grade iron ore associated with manganese clay by selective flocculation. The representative samples obtained for this purpose were initially subjected to chemical and mineralogical studies. The chemical analyses indicated 42.56 % Fe, 6.25% Mn, 8.72 % SiO2 and 13.60 % Al2O3 in the representative sample. The mineralogical analyses carried out under optical microscope showed that the ore mineral predominantly comprised of iron oxides and hydroxides along with manganese and silicate as gangue minerals. Prior to the beneficiation studies, the samples were subjected to settling tests. These tests were carried out by using poly acrylic acid (paa), poly acryl amide (pam) and guar gum (gg) as the flocculants. From these studies it was observed that settling rate of particles increases with increase in pH and a maximum settling rate of 0.23 cm/secwas obtained at pH 9 in presence of poly acryl amide. Further, the samples were subjected to selective flocculation studies using above-mentioned reagents. From these studies better results were obtained in the experiments carried out with poly acryl amide as the flocculant. Thus, it was possible to upgrade the iron content from 42.5 to 53%, with a recovery of 92%. However, 51% Fe with recovery of 87% and 50% Fe with recovery of 94 % was obtained using poly acrylic acid and guar gum respectively.

Sep 1, 2012

By X. O. Xia

This paper introduces a kind of flotation machine for nonferrous metal, ferrous metal and non-metal minerals. With the application and development of flotation machine, researching the designment of master parts, including tank, impeller, stator, false bottom. Through the commercial run to validate the correctness of designment, achieving satisfied technical and economic target and supplying a kind of efficient and reliable flotation machine.

Jan 1, 2014

By H. J. Cao

Valuable elements could be extracted by microorganism ferment fluid from bauxite, which mainly due to bacteria acid namely organic acid. And after leaching, reclaiming the remainder organic acid in leaching solution was an important procedure for bauxite leaching process. the re-searching status about organic acid reclaiming process from bauxite ore bioleaching solution was summarized. Common processes for recycling organic acid from bauxite bioleaching solution in this period and their advantages and disadvantages, research aspects which need being confirmed for the future were Indicated

Jan 1, 2014

The air recovery from a flotation cell is the fraction of inlet air which overflows the weir as un-broken bubbles. The air recovery is an important factor in froth phase phenomena; such as gangue entrainment and froth recovery. Increasing the air recovery, results in a higher recovery of attached mineral particles. Air recovery can be measured experimentally on plant using image processing of the top surface of an overflowing froth. The air recovery is directly linked to froth stability and the bursting rate of the bubbles at the froth surface, making it very difficult to predict. Experimental results show a very strong correlation between the superficial velocity of the inlet air and the superficial velocity of the air leaving the cell through the froth surface due to bursting, calculated from the experimentally measured air recovery. This correlation holds over multiple banks from different plants. Development of a power law equation around the inlet air velocity and the bubble solids loading on the froth surface allows the superficial air velocity through the top surface of the froth to be predicted, and from this the air recovery. This model is valid for use when operating beyond the peak in air recovery.

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 Yu. Gurevich, M. Teremova, I. Prokopev, A. Razvjaznaya, N. Algebraistova

"The objective of this work is the scientific justification and development of efficient and environmentally-friendly method of bulk concentrate preparation for selection with application of microbiological practices. This research suggests to apply Pseudomonas Japonica bacterial culture to the bulk concentrate before the selection circuit in order to clear the surface of sulphides from the xanthate skin. It is also suggested to apply bacterial consortium Ochrobactrum ?nthropi and Pseudomonas aeruginosa JCM 5962 for desorption of diesel residual concentrations. High-efficient and environmentally friendly method of copper-molybdene and lead-zinc bulk concentrate selection was developed based on theoretical and experimental research work with application of microbiological practices. In comparison with conventional methods (steaming, sodium sulphide washing) the above suggested bio-technological method of bulk concentrate preparation before selection cycle will allow to reduce material and power expenditures, and it is also environmentally friendly. INTRODUCTION High-efficient selection of sulphide bulk concentrate is gained exclusively after collecting agent is removed from mineral surface. Therefore, the problem of bulk concentrate preparing before the selection cycle is acute, since the further technological parameters of the subsequent separation depends on the effectiveness of pulp preparation. Existing traditional ways of bulk concentrate preparation. such as washing or steaming, are characterized by high energy and material costs in industrial conditions [1,2]. The microbiological treatment before separation of the bulk concentrate into different kind of concentrates appear one of perspective processes for treatment of bulk concentrates [3,4]. At the present time, the world practice of processing mineral raw materials demonstrates the wide application of technologies using microorganisms: bacterial leaching and oxidation, purification of industrial wastewater. This is due to the fact that biotechnological methods are environmentally safe, low-cost, and suitable for refining complex ores and raw materials of industrial origin."

Jan 1, 2018

By Thenepalli Thriveni, Seong-Young Nam, Nam-Il Um

New modern water treatment technologies required for arsenic removal from waste waters contaminated extensively by various background sources from mining, industrial waste, agricultural waste, painting industry and natural geological bed rock system etc. Arsenic is a widely dispersed element in the earth's crust and exists at an average concentration of approximately 5 mg/kg. Arsenic (As) and heavy metals may be released from the mine wastes to the ground and surface water systems, as well as the geological environment due to their solubility and mobility. This research focuses on the effect of accelerated carbonation process for successful removal of heavy metal arsenic anions from artificial waste water and mining waste waters. This accelerated carbonation process is a simple and novel method with 85 ~ 88% removal efficiency. Carbonation has been studied as a process to further improve immobilization of solidified/stabilized waste and granular waste. After successful removal of arsenic anions from solid mining waste and its potential benefits for producing construction materials. Besides, the industrial and urban management systems are generating bulk solid mining wastes, and most often dumping them in open fields. To prevent the landfilling with mining waste, many efforts are being made for the recycling of different types of mining solid wastes with a view to utilizing them in the production of various construction materials.

Jan 1, 2014

By S. K. Chaurasiya

o meet the ever increasing demand of iron oxide feed stock for rapidly growing domestic steel industries and to effectively manage the depleting reserve of high grade lumpy iron ore, Pelletization of iron ore fines/slimes are expected to play a dominant role in the near future. Use of pellets will also enable the blast furnace operator to achieve higher levels of productivity with lowering of operating cost. The effective utilization of Iron Ore Slimes is important not only from the point of view of optimum utilization of Iron values in the mined ore but also for preventing environmental pollution. A significant amount of slime is being accumulated at the tailing dam of one of the iron ore mines and with the present scale of operation the tailing dam will be filled in another 10 years. Hence to increase the life of tailing dam and for better utilization of the iron values a study has been carried out for the suitability of pellet manufacturing with slimes and fines at our laboratory. The pelletization studies are aimed for optimization of various parameters for production of Blast furnace/ DR grade pellets from beneficiated slimes and Fines. This paper attempts to describe the production of blast furnace grade pellets from beneficiated slime and fines and its characterizations.

Sep 1, 2012

By Y. H. Zhang

Mechanism of BK501 in desiliconization from bauxite was studied by use of flotation test, EDS, ?-potential, FTIR. Results of flotation show that almost all of diaspore can be depressed when BK501 is put into pulp ranging from pH 4~12, in the meanwhile kaolinite is slightly activated. In the light of surface analyses, it is concluded that the adsorption of reagent on the diaspore is dominant by chemical interaction. Moreover, kaolinite may float more by addition of BK501 because of flocculation.

Jan 1, 2014

By Y. M. Zhu, G. C. Gong

"The influences of citric acid (CA) on the flotation behavior of cassiterite using styrene phosphonic acid (SPA) as the collector were studied via single mineral flotation tests, contact angle measurements, zeta potential determinations and solution chemistry calculations in this paper. The results of single mineral flotation tests revealed under the conditions that pH=4 and the dosage of SPA 100 mg/L, the recovery of cassiterite reached 76.78%. The addition of 20 mg/L AC decreased the recovery by 12.42% at pH=4. Contact angle measurements demonstrated the adsorption of CA prior to SPA made the cassiterite more hydrophilic. The results of zeta potential determinations and solution chemistry calculations indicated the chemisorption of C6H7O7- and C6H6O72- filled parts of the Sn site on cassiterite surface and prevented the SPA from getting adsorbed. The hydrophilic effect of AC was stronger than the hydrophobic effect of SPA and the flotation of cassiterite was crippled. INTRODUCTION Tin is an important metal which is widely used in medical instruments, marine engineering materials, electronic and electrical devices, welding, weapon manufacturing and organotin compounds industries (Angadi et al., 2015). Cassiterite is the only mineral from which the tin can be extracted, thus it is of great importance to efficiently exploit the cassiterite mineral. Flotation is an indispensable method for the recovery of cassiterite (Li et al., 2015). However, cassiterite is usually in association with many other gangue minerals which are of similar floatability, such as quartz, calcite, fluorite, iron oxide, wolframite, scheelite and tourmaline (Sreevinas, 1997). So some modifiers are necessary in the cassiterite flotation process. The amounts of the modifiers used in the flotation must be judicious and the overmuch modifiers may cripple the recovery of cassiterite (Parsonage et al., 1987). Nevertheless, the research about the effects of the modifiers on the flotation behavior of cassiterite has been rarely reported. In this paper, the influences of citric acid (CA) on the flotation of cassiterite using styrene phosphonic acid (SPA) as the collector were investigated by flotation tests, contact angle measurements, zeta potential determinations and solution chemistry calculations."

Jan 1, 2018

By Zehong Wang

Selecting sodium polyacrylate (PAAS) as grinding aid, the effect of grinding aid on the grinding efficiency of bauxite taken from Shanxi province was studied and its mechanisms were analyzed by measuring the variation of adsorption characteristic, pulp viscosity, surface electric potential of the bauxite and the surface appearance of particles. The results showed that, compared with no grinding aids added the content of -0.074mm in the ground product was increased by 5.45 percentage points under the optimal grinding conditions adding PAAS as grinding aid when the amount of PAAS was 0.7%wt of bauxite. Because the physical adsorption and chemical adsorption were occurred on the bauxite surface, which could reduce the pulp viscosity, change the surface electric potential of the bauxite, enhance the surface appearance of particles and lower the surface hardness of the bauxite, the grinding efficiency of bauxite was increased by PAAS. Keywords: bauxite, grinding aids, grinding efficiency, mechanism

Sep 1, 2012

By M. F. He

The depression of pyrite in marmatite flotation by a new depressant Sodium Glycerine-xanthate (SGX) has been investigated through microflotation, zeta potential, and adsorption measurements in systems open to the atmosphere. The flotation tests of single mineral show that in the presence of SGX, marmatite can be activated by Cu2+ and shows good flotability, while pyrite can?t be activated and therefore shows poor flotability, as a result these two minerals can be separated using butyl xanthate as the collector. The depression mechanism of SGX on sulfide minerals is discussed based on Zeta potential and adsorption isotherm. Zeta potential experiments demonstrate that at the presence of Cu2+, SGX can strongly adsorb on the surface of pyrite, while it can?t adsorb on the surface of marmatite, thus the results are in accordance with those of flotation experiments; the results of adsorption isotherms show that the adsorption density of SGX on pyrite is greater.

Jan 1, 2014

By K. Saberyan

In this study, solvent extraction of zirconium by using triphenylphosphine oxide as extractant has been investigated. The results showed that extraction of zirconium by triphenylphosphine oxides in nitric acid and hydrochloric acid media were negligible. Extraction of zirconium in acetic acid media with concentration of 0.01~0.2 M has been studied and the results showed that the maximum percent of zirconium extraction was 40% in acid acetic with concentration of 0.01 M. By addition complexing agents such as potassium thiocyanate with the concentration of 0.01~0.2 M zirconium extraction increased up to 86% in 0.2 M potassium thiocyanate. By addition of sodium salicylate with concentration of 0.01 M and in pH=2.5, the maximum extraction of 96% was achieved. The striping of zirconium from organic phase can be carried out by 0.5 M solution of sulfuric acid.

Jan 1, 2014

By Y. Rama Murthy

Around 90% of the chromite resources of India are concentrated in the Boula-Nuasahi Sukinda belt of Orissa state. In order to conserve these valuable ore resources strategically, several companies established chrome ore beneficiation plants in this region. The general beneficiation process in these plants consists of gravity unit operations such as Floatex density separator, spiral, wet shaking table etc. Most of these gravity circuits suffer huge losses of valuable minerals in the tailing. Any attempt towards decreasing these losses would not only increase the limited reserves in India but also make the economics of the operations more attractive. Apart from the liberation phenomena, in many of the operating plants considerable quantity of values are lost in the tailings, due to inconsistent feed quality, inappropriate selection of operating and design parameters. Mineral engineers in this regard have to play a proactive and continuous role to improve the performance of all separating units by modifying even small changes based on tests conducted in laboratory under controlled conditions followed by attempts to make necessary changes in the plant. For such improvements, accurate data collection and proper data interpretation followed by making necessary change which is implementable in an operating plant play a very critical role in performance of the circuit. Databank collected over a period of time under various conditions would also help in overcoming the future problems related to either variation in the feed characteristics or specific demand by metallurgical industries. The above concept was adopted in one of the operating chromite beneficiation plant at Sukinda. The approach adopted and practical problems encountered during the study were reported in this paper. The result of trial campaign has shown that, an overall product assaying 30.2% Cr2O3 from the feed (18% Cr2O3 ) can be produced to in single stage. The final discards of the process contain 12% Cr2O3. Keywords: chromite, chromite beneficiation, chromite losses, gravity concentration techniques, plant operating data bank

Sep 1, 2012

By Wang Xu, Tao Dongping, Zhang Jie, Tao Youjun

Based on the principle of fly ash triboelectrification, the mineral electrical index and testing method are introduced. The electric differences of various mineral components of fly ash are discussed in view of the results of chemical and mineral composition analysis of the fly ash sample acquired from the Xin-wen power plant. The dielectric constant and charge-mass ratio of carbon and ash in the fly ash are determined. The data were then used along with the rotary triboelectrostatic separator (RTS) testing results to investigate the charging characteristic of fly ash particles in different sizes. The results show that the dielectric constant of fly ash with different particle size decreased with the decrease in particle size, which led to a poor electrical conductivity. Thus particle size has an important effect on conductivity. The charges of carbon and ash particles increased with decreasing particle size. The charge-mass ratio of carbon and ash particles of the same size increased with decreasing particle size. This indicates that finer particle size is more favorable for triboelectrification separation from the charging efficiency point of view. The rotary triboelectrostatic fly ash separation tests show that the best decarbonization performance was achieved with particles in the size range of 0.038-0.074mm with which the decarbonization rate and efficiency index reached 38.93% and 120.83% spectively.

Jan 1, 2014

By M. Roy

Coke combustion during sintering process is significantly governed by coke breeze size distribution, which in turn affect sinter quality i.e. sinter granulometry, Tumbler index, Reduction Degradation Index and Reducibility Index of sinter. To know the effect of microfines of coke breeze on sintering process parameters, pot sintering tests were conducted and it was found that when microfines are eliminated and optimum coke size (1-3mm) is used yield of sinter increased by more than 7%. Similarly productivity increased by 9%, the strength of sinter i.e. ISO Tumbler Index increased by 2.3% and +10mm sinter size increased by 5.5%. Controlling of microfines during crushing and by improving crushing index will result in improved quality and productivity of sinter with lesser amount of coke breeze. This paper describes that how to optimize solid fuel i.e. coke breeze consumption in sintering process through granulometry control. Keywords: iron ore sintering, coke breeze granulometry, productivity of sinter, quality of sinter

Sep 1, 2012

By Tasuma Suzuki

Electrokinetic/permeable reactive barrier system is a promising in situ soil and ground water remediation technique to reduce toxic NO3- into less toxic NH4+. Using granular zero-valent iron (Fe0) as a reductant, the first objective of this study was to investigate the influence of the solid-liquid ratio and aqueouspHon NO3- reduction. The results obtained from a series of batch experiments showed that NO3- reduction was enhanced by either increasing solid-liquid ratio or decreasing aqueous pH. Based on insights obtained from batch experiments, the second objective of this study was set to design the remediation conditions of the electrokinetic/Fe0permeable reactive barrier system to maximize the NO3- reduction efficiency. Experimental results showed that the effectiveness of the system strongly depended on the Fe0 percentage in the reactive barrier, the pH in the anode reservoir, and the applied voltage, which were consistent with the results obtained from batch experiments. Under optimized treatment conditions, nearly 100 % NO3-was reduced into NH4+ in the permeable reactive barrier and collected in the cathode reservoir. Insights obtained from this study provided fundamental information on roles each of remediation design parameters plays, and will be useful to optimize the remediation conditions. Keywords: electrokinetic remediation, permeable reactive barrier, zero-valent iron, nitrate

Sep 1, 2012