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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 Z. T. Yuan, S. L. Qi, Q. Y. Meng, G. X. Zou, L. X. Li, J. W. Lu

"The selective separation of pentlandite from serpentine was investigated using the magnetic coating-magnetic separation by conditioning slurry pH value, stirring speed, magnetic field intensity and controlling dosages of sodium hexametaphosphate (SHMP) and sodium oleate (SO). The optimal conditions were obtained as follows: the natural pH of 6.8-7.2, stirring speed of 2300 rpm, magnetic field intensity of 200 kA m-1, SHMP of 60 mg L-1, and SO of 400 mg L-1. Results showed that the Ni grade was 21.4% with the Ni recovery of 81.4% and MgO content of 3.8%. FTIR indicated that coagulant of SO preferentially adsorbed onto pentlandite and magnetite particles while hardly adsorbing onto serpentine particles when dispersant of SHMP was used. Thus, the selective magnetic coating of magnetite on pentlandite surfaces could be formed due to the formation of hydrophobic surfaces on pentlandite and magnetite particles. Calculations of DLVO (Derjaguin-Landau-Verwey-Overbeek) confirmed that interactions between magnetite and pentlandite particles were much stronger than that between magnetite and serpentine due to the existence of hydrophobic interactions with the addition of SO. Consequently, the pentlandite was successfully separated from serpentine. Therefore, this study exhibits the potential to separate pentlandite from serpentine minerals for practical applications and thus deserves further study.INTRODUCTION It has been well known that the separation of pentlandite from serpentine is a worldwide challenging issue in the processing of sulphide nickel-copper ores. Because the serpentine mainly causes the high pulp viscosity and slime coating on the pentlandite, which interferes with the flotation process of pentlandite (Cao et al., 2016; Feng et al., 2012). The fibrous mineral of serpentine preferentially attaches to the air bubble, forming bubble-macrofibers aggregates, which are easily floated into the nickel concentrates, resulting in the decline of Ni grade (Alvarez-Silva et al., 2016; Kusuma et al., 2014). In addition, the serpentine adheres to the pentlandite as hetero-aggregation or slime coating via the electrical interaction between a positively charged serpentine and a negatively charged pentlandite, which decreases the hydrophobicity of pentlandite and reduces the collector adsorption (Feng et al., 2013). In other words, the presence of serpentine or the occurrence of aggregates (including slime coating and bubble-macrofibers aggregates) seriously affects the flotation process and deteriorates the flotation of pentlandite. Therefore, we propose magnetic separation to recover pentlandite from serpentine with the magnetic coating technology, which is different from forth flotation."

Jan 1, 2018

By B. K. Saikia

A preliminary attempt has been made to study the particle size distribution (PSD) of minerals in one of the industrially important pulverized Indian coal sample using computer-controlled scanning electron microscopy (CCSEM). The results show that clay minerals, quartz, pyrite, and pyrrhotite form the bulk of the mineral matter. Minor minerals, such as calcite, dolomite, ankerite, barite, oxidized pyrrhotite, and gypsum are also observed in the coal sample. The PSD of the included minerals is generally observed to be finer than that of the excluded ones in the coal. Thus, the coal rich in included minerals has more small mineral particles, which may affect its reactivity. The proportion of included to excluded is found to be higher in major cases. Si is found to be mostly occurred as quartz and clay minerals, while Al mostly occurs as silicate minerals. Fe is primarily present as iron sulfides, iron oxide, and Fe-Al-silicate. S is partitioned into iron sulfides and gypsum. Most Ca occurs as carbonates and gypsum, with a minor fraction associated with clay minerals. Mg is found to be mainly present as dolomite and clay minerals, with a very minor fraction present as ankerite. The majority of alkali elements are associated with aluminosilicates. P is mostly associated with kaolinite and/or present as more complex compounds containing Al, Si, and other elements as apatite are found to be absent in the coal studied. Ti is mainly present as rutile and kaolinite. The geo-chemical association of the trace elements has also been discussed. Keywords: minerals, Assam coals, Indian coals, CCSEM study

Sep 1, 2012

By M. Blagojev, R. Tomanec

"Studies reported in this paper used polymetallic Pb-Zn-Sb-As-(Ag, Au) ore from Dražnja, Kosovo. The ore is comparatively rich in Zn (6.56%) and Pb (2.87%), but with high rates of Sb and As. Conventional lead and zinc concentration by flotation produced galena and sphalerite rich concentrate with high recovery, but with excessive As and Sb. After chemical analyses, which could not detect the reason for the excessive elements, ore minerals were identified under the ore microscope, their texture characterized, and degree of liberation of useful minerals was assessed. Microscopy of the mineral concentrates revealed complex intergrowths of galena and marmatite minerals mostly with sulphosalt minerals (boulangerite, jamesonite and bournonite) and also with arsenopyrite mainly responsible for the unsatisfactory quality of the concentrate. These complex sulphosalts, among other things have similar behaviour during the flotation concentration, and in spite of their interlocking with galena, therefore inadequate liberation, sulphosalts remain in the lead concentrate. Microscopic analyses indicated that a better galena concentration product is possible with a higher rate of mineral liberation, and then by selective floc flotation of some sulphosalt minerals. Purpose of this work was to show that only chemical analysis is not sufficient, according to that we solved the problem by precise mineral identification and time consuming mineral liberation measurements. INTRODUCTION The polymetallic Pb-Zn-Sb-As-(Ag, Au) ore body of Dražnja, Kosovo, fairly rich in Zn (6.56%) and Pb (2.87%) was repeatedly explored and once even worked. Mineralization at Draznja was primarily represented by sphalerite, galenite and marcasite/pirite. Some sections comprise massive sulphides, and others are lower grade zones of semi-massive sphalerite/galena or marcasite/pyrite dominant sulphides. The ore body II was formed in the southern gallery in the structure Çukë – Lajthishtë (with content of 3.16% Pb and 7.31% Zn). Pb-Zn ore with increased content of As, Sb sulphosalts is not rare phenomenon in the world. While previously treated as unprofitable, economical uninteresting ore, today with development processing and new reagents (organic, ecologic), are the topic of scientific papers. The examination of Pb-Zn ore with high content of sulphosalts we find in deposits as: The hydrothermal vein deposit of Harja in the Baia Mare area, contain a wide variety of sulphosalts [Cook, N. & Damian, G., 1997]; also the deposits Fankou Mine in Guangdong Province and the Dachang Mine in Guangxi Province, where the flotation concentration of galena and jamesonite takes place [Runqing Liu et al. 2015], [Zhang Ting, Qin Wen-Qing, 2015];. On a samples from Tibet in China flotation separation test of galena and jamesonite was conducted [Sun Wei, Han Haisheng, Tao Hongbiao, Liu Runqing, 2015]. According to history of investigation, the mineralized area of Dražnja has a long history of exploration and possible exploitation activities [Slowey, Galen, 2009]. Recent workings were carried out in three stages through the 20th century."

Jan 1, 2018

By S. V. Balikov

A close association of fine gold with pyrite and arsenopyrite is observed at many gold ore deposits. Gold forms and gold distribution in sulfides of different deposits were studied. A comprehensive method including optical spectrum analysis, X-ray diffraction analysis, high-temperature X-ray diffraction analysis, scanning electron microscopy and X-ray microanalysis was used for the de-tailed investigation of the defectiveness of the structure of pyrites from different deposits. It was shown that gold content in pyrites varied from 1.5 g/t to 100 g/t compared with 30 g/t to 230 g/t in arsenopyrites. The nature and arrangement of inner inclusions of foreign minerals in pyrites as well as occurrence of fractures and macro- and microdefects were examined. Iron, sulfur and arsenic contents in all pyrite samples were determined. Chemical composition of the detected inclusions was defined. Parameters of submicroscopic structure of pyrite were estimated using X-ray Fourier line shape analysis. Estimation of real structure characteristics with calculation of submicroscopic D-blocks and root-mean-square lattice deformation 2()evalues was performed. Defectiveness of the pyrite structure can be defined by the following parameters: K?1 and K?2 reflection resolution and its intensity within high Bragg angles; S content to Fe content ratio; the arsenic content and the local variation in its concentration within the pyrite grain; the size of submicroscopic blocks and the crystal lattice disturbance value. The performed analysis showed some relationships between these parameters and refractoriness of the pyrite concentrates. It was observed that at S/Fe ratio close to or higher than stoichiometry and at a low arsenic content (less than one per cent) pyrite concentrates were not refractory. The analysis results showed that concentrates of the Beryozovskaya gold plant (0.02~0.07 As%) and concentrates of the Kommunarovskaya gold plant (less than 0.05 As%) as well as some pyrites from the Sukhoi Log gold deposit had the same characteristics. It was found that average arsenic content did not excess 0.2 per cent. Arsenic distribution within the grain of all these pyrites was uniform. At S/Fe ratio lower than or close to stoichiometry and at high arsenic content (more than one per cent) and significant variation in its distribution within a pyrite grain the pyrite concentrates are refractory. Such pyrites are typical for the Sukhoi Log, the Bakyrchik and the Mardzhanbulak gold deposits. Direct correlation between arsenic and gold contents, in particular, in fine grains of pyrite was observed by many researches. This correlation was explained by impregnation of arsenopyrite which normally contains more gold than arsenic pyrites. The analyses results showed that no arsenopyrite impregnation was found: arsenic distribution within the grain was uniform but its concentration varied greatly. Such pyrite concentrates are more refractory. This paper presents the results of analyses of sulfides to determine the amenability of the associated gold recovery by hydro- and pyrometallurgy.

Jan 1, 2014

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

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

Jan 1, 2014

By L. Rintala

The design of a hydrometallurgical process starts with the analysis of the raw materials to be treated, for example mineralogy, chemistry, deposit size are analysed. Based on this information suitable unit processes for pre-treatment, leaching, solution purification and product recovery are selected. Typically, process design for the new ore deposit relies on laboratory tests such as pre-treatment and leaching experiments. The experimental work is the most time consuming and expensive part of the process design. Reducing the number of experiments would shorten the time of designing a new flowsheet or development of new process technology. A large amount of information is available about the hydrometallurgical experiments and the amount is increasing continuously. For example, word search using ?hydrometallurgy? from Scopus database results in over 4 000 publications with the word in title, abstract or keywords. This number consists of 2 500 articles, 900 conference papers, and 90 reviews since 1972. The number of hydrometallurgical publications per year has increased from 13 in 1972 to 150-200 in the last few years. The objective of this study was to analyze how detailed data of experiments about the gold extraction is published and how that data could be exploited more effectively when designing hydrometallurgical processing for new ore. The leading idea is that similar ores should have the similar response in leaching. If the published information was used more efficiently, the amount of experiments would be reduced. More than 200 cases of experimental data of gold leaching have been analyzed for this study. There are over 30 factors that could be used in comparison when selecting process alternatives, but challenging fact is that not all these factors are documented in all publications. Results show that the usefulness of the published data in the development of hydrometallurgical flow sheet for gold using decision-support tools is not that straightforward. The quality of the published information about gold extraction varied between the publications and the descriptions of the raw materials, experimental arrangements and results were often missing details. Methods to normalize the data for description of the cases and a system to describe different features unambiguously are needed. Keywords: refractory gold, host mineral, leaching, data analysis, case-based reasoning

Sep 1, 2012

By H. M. Gao

According to the difficulty of dolomite removal from collophanite,normal-reverse floatation process has been adopted in floatation with the use of highly selective collector G-4 and depressant S721. Good indexes of flotation have been obtained with the run-of-mine ore containing 17.96 % P2O5 and 2.31 % MgO being upgraded to a concentrate containing more than 30% P2O5 and less than 1% MgO. The reagent interaction mechanism in low grade collophanite flotation has been stu-died by FTIR analysis and theoretical calculation. The results indicate that the interaction between collector G-4 and collophanite is the result of chemical adsorption in combination with physical ad-sorption with chemical adsorption playing the major role. Depressant S721 adsorbs on dolomite surface to form a water film and effectively depresses the flotation of dolomite and reduces the MgO content in the concentrate.

Jan 1, 2014

By R. S. Wang, S. Z. Zhou, L. Wan, K. W. Zeng, Z. J. Sun, W. G. Wu, Z. B. Qian, X. R. Zhang, Z. K. Hu, Y. Yu

"In view of the present situation that the traditional environment friendly depressants for galena aren’t very effective in the separation of mixed concentrate including copper sulfide and lead sulfide, this research describes a new environment friendly depressant PD-1 and investigates its effects and mechanism in the separation of chalcopyrite and galena. This study is carried out through flotation tests, analysis of infrared spectra and absorption measurements. It is shown that when O-isopropyl-N-ethyl thionocarbamate (Z200) is used as collector, chalcopyrite and galena can be separated in the presence of PD-1 under appropriate conditions. Therefore, it can be concluded that PD-1 has an excellent depression ability and great selectivity for galena. Meanwhile, analysis of infrared spectra demonstrates that PD-1 can strongly absorb on the galena surface by chemical interaction with Pb2+, while it hardly absorbs on the chalcopyrite surface. In addition, the results of absorption measurements reveal that competitive adsorption occurs on the galena surface between PD-1 and Z200, PD-1 can block the absorption of Z200 on the galena surface. However, PD-1 has a little effect on the absorption of Z200 on the chalcopyrite surface under above conditions. What’s more, the hydrophilic groups of PD-1 molecules can make galena effectively depressed. The results of mechanism analysis are in accordance with those of flotation tests.INTRODUCTION In the processing of copper-lead sulfide ores, the process, copper increase and lead reduction (Zhang et al., 2017) after reagents removal of rough concentrate produced by mixed flotation of chalcopyrite and galena, is usually adopted. However, as a result of tight symbiosis and the similar flotability of chalcopyrite and galena, the separation is difficult (Hu and Feng, 2006). There are 3 kinds of depressants for galena in the separation of chalcopyrite and galena concentrate,including dichromate, sulfite and combined depressants of organic or inorganic reagents (Wei, 2012). As dichromate would cause serious environmental pollution, it is gradually banned to be used in industry (Xu et al., 2017; Lin et al., 2017). what’s more, due to the need of acidic slurry, using sulfite is not conductive to the maintenance of equipment and stable production(Wang, 1999). As for the combined depressants, they also have disadvantages of complex pharmaceutical system and no ideal separation effect (Wei and Sun, 2008). Therefore, the development of new safe and effective depressants for galena is a research focus for researchers in the minerals processing (Chen, 2000). In this paper, a new type of organic depressant PD-1 is applied to the copper-lead separation process of ""copper increase and lead reduction"" using Z200 as the collector. In addition, the performances and mechanism of its depression to galena are studied emphatically."

Jan 1, 2018

By Herman D. Mendoza

"The removal of finely dispersed mercury from the effluent of small-scale gold mining operations and the eventual recycling of the recovered mercury was investigated. The conventional method of amalgamation, or “ball milling”, involves the mixing of a substantial amount of mercury with ore to recover free gold during the grinding stage. During grinding, a portion of the mercury is transformed into minute droplets, which readily float and disperse in the effluent. A kilo of gold ore containing 20-30 g Au/t, when ground with 3 g of mercury, yields 0.005 to 0.050 mg/l of mercury in the effluent, exceeding the concentration of 0.002 mg/l allowed by law for surface water.A rapid recovery/ recycling process was introduced using the surface-chemical properties of finely dispersed mercury in aqueous suspension. It was observed that fine droplets of mercury in an aqueous environment readily attached onto a collector having positive surface potentials for pH 3 to 10. An example of a suitable collector is alumina (Al2O3), which has an iso-electric point of pH 9.8. When an effluent, coming from a settling procedure after an amalgamation-grinding stage, was passed through a column-bed packed with alumina fiber, removal and subsequent collection of finely dispersed mercury occurred under acidic conditions, pH 3-6. Recovery was around 99.5%, yielding an acceptable quality of water safe for disposal into the aquatic environment. The collected droplets of mercury, which are left in the column-bed of alumina fiber, were subsequently treated with a cleansing solution at alkaline conditions pH 10 -12. At these conditions, both mercury and alumina fiber carry negative surface potentials, which results in the eventual detachment of attached mercury from the alumina collector. The effective recovery of attached mercury from the alumina collector by the detachment procedure is only 30-35%. The collected mercury from the cleansing stage can be collected, cleaned and can be used for subsequent amalgamation processes. The attachment and detachment behaviour of finely dispersed mercury onto and from the microscopic collector alumina is shown in Figure 1. The result of attachment and detachment were analyzed using existing interaction energy theories like the Darguin-Landau- Verwey- Overbeek (DLVO) Theory."

Jan 1, 2003

By Yuriy V. Gulyaev, Galina V. Sedelnikova, Valeriy D. Lunin, Valentin A. Chanturiya, Igor J. Bunin

"In Russia the industrial exploitation of ore deposits is determined as a strategic direction of gold extraction industry development. The majority of gold-containing ores of Russia is referred to category of rebellious ores with 3-5 g/t gold content and is characterized by low factors of gold and silver extraction under cyaniding. The resistance of goldcontaining raw materials under their processing is caused by presence of very fine gold particles less than 0,1-0,01 µm in size, associated with the pyrite and arsenopyrite. Significance of the problem of rational rebellious ores beneficiation and high precious metals extraction is increasing from year to year.Group of scientists from IPKON and IRE, Russian Academy of Sciences, has developed highly effective, powereconomic and ecologically clean method of breaking-up of resistant gold-containing ores and their beneficiation products on the base of using an energy of powerful electromagnetic pulses. For the first time there have been designed laboratory installation for resistant raw materials treatment in dry and wet state (solid/liquid ratio = 5:1) and ground material less than 1-0,5 mm.Mechanisms of powerful electromagnetic pulses action on natural mineral components, including dielectrics (quartz, calcite), semiconductors (sulfides) and metals (gold, silver) have been theoretically accounted. Pulses action parameters and ways of pulses generating have been discussed in different conditions. At tension of electromagnetic field, exceeding the electric strength of processing material, an electric breakdown develops in the mineral matrix of sulfides and dielectrics. Under the series of pulses action the forming of plural breakdown channels occurs, leading to strength loss of material and microcrackes developing. Thus, the action makes it possible for leaching solution to access precious metals particles under cyaniding process. Distinctive changing of pyrite and arsenopyrite surface structures under the influence of powerful electromagnetic pulses is confirmed by studies using optical and scanning electron microscopy."

Jan 1, 2003

By A. Shibayama

Soil contamination by organic compounds is one of the most concerned issues on polluted soil. It is well known that there are limited methods to remediate the contaminated soil on site. Especially, the in-situ method for contaminated soil is too difficult to de-contaminate the organic pollutant. In this study, the fundamental ability of soil remediation, which aimed to decrease oil concentration in, in-situ process, have been researched by using a high pressure gas generated from ?crush composition? on artificially oil contaminated soil. The n-hexadecane (n-C16H34) and other organic compounds were selected as soil oil contaminators, gravimetric analysis by soxhlet extraction and GC-MS were used as qualitative and quantitative analysing methods. For the experimental examination, the influences on the difference in the concentration of n-hexadecane (and other organics), the tamping amount, position and repetition of crush composition in soil, and scale (size) of experimental model were investigated. The n-hexadecane concentration reduced by the explosive effect of crush composition showed a reasonable decrease of about 30 wt%~60 wt% compared to the initial n-hexadecane. The removed amount of n-hexadecane and distance from explosion point of the crush composition was related in scale and model of contaminated soil.

Jan 1, 2014

By Sarah K. DeBono, Alan J. Monaghan, Emmanuel V. Manlapig, Gregory J. Harbort

"The Jameson Cell is a type of flotation machine in which air and pulp are brought together in a vertical tube called a downcomer. Within the downcomer the air and pulp are dispersed into a dense foam of fine bubbles, which creates a favourable environment for bubble-particle collision and subsequent collection of hydrophobic particles. The intense collection zone within the downcomer can be considered similar to the zone between the rotor and stator in mechanical flotation cells.Research into the bubble-particle collision and fluid dynamics of mechanical cells rotor-stator zone has been limited by the difficulty of achieving accurate measurements in production sized machines. With the Jameson Cell the downcomer is largely external and separated from the flotation tank, allowing ready access to the primary contacting zone for measurement and analysis.An investigation has been undertaken into the operating characteristics of the downcomer relating to bubble-particle collision. An effective mapping of the downcomer has been made through measurements of void fraction and bubble size taken across cross sections of the downcomer. Analysis of these measurements has provided an interpretation of the variations in the air and fluid dynamics, bubble size and distribution throughout the downcomer chamber."

Jan 1, 2003

By Leon Lorenzen, Trevor J. Britz, Pierre J. Van Zyl, Ellis R. Els

Enhanced granulation of UASB granules was tested on pilot scale with two different test reactors (about 5 litres capacity each). Sludge from a local sewage works was used, with peach cannery effluent as carbon source. Cyclic motion of the reactor contents, and a daily replenishment of feed material create the necessary stress conditions for enhanced growth. Sizable granules, bigger than 0.5 mm, were produced within 20 days. Of the two reactors tested, the reactor equipped with a horizontal agitation shaft proved more effective.

Jan 1, 2003

By T. Khonthu

The purpose of this investigation was to evaluate the relationship between different milling procedures, viz. a ball mill and an IsaMill respectively, and the flotation performance of the different mill products. Two ores were used, viz. a base metal sulphide (BMS) and a platinum group mineral (PGM) UG2 ore. Flotation was used as a diagnostic to investigate whether the different milling procedures may have different effects of the floatability of the particles. The present study is part of a research programme investigating this question using a wide range of comminutiondevices and procedures. Similar particle size fractions from the different milling procedures were used in the flotation tests. The particles were characterized in terms of particle size distribution, morphology (using scanning electron microscopy and image analysis software) and rheology tests. The results have shown that in general when comparing similar feeds to flotation in terms of equivalent particle size distributions as indicated by the d80 value, the ball mill generally yielded better recoveries and grades in the case of the BMS and lower chromite recoveries in the case of the UG2 ore compared to the IsaMill. No significant differences were observed in the morphological or rheological characteristics of the particles subjected to the different milling procedures. Although the results appear to indicate that IsaMilling is less advantageous than ball milling in terms of the flotation performance for the two ores studied it should be emphasized that these results do not take into account the relative advantage which IsaMilling has over ball milling in terms of direct and indirect energy consumption and GHG emissions nor, most importantly, does it consider the platinum group element recoveries in the case of the UG2 which may have increased significantly as a result of the finer grind which the IsaMill produces after 4 passes compared to the ball mill after 64 min. Such results which will be reported is due course may show that the greater liberation expected after IsaMilling of the PGMs outweighs any disadvantages indicated in this study.

Sep 1, 2012

By A. P. Purgin, M. G. Viduetsky, I. F. Garifulin

"The combined treatment process for mine, tailings storage facility, quarry, circulating, and waste water in the mining and metals industry brings together the conventional chemical treatment processes and pneumatic flotation cells of the KFM series. The key principle of the process is preparing the water for treatment by saturating with finely dispersed air bubbles in the flotation cell blowers. Gas-air lift dispersers located in the lower part of the cell body additionally saturate the cell’s contents with finely dispersed air. Due to the residual content of flotation agents in the treated water, hydroxide ion-air aggregates form at the aerator outlet, supporting the efficient precipitation of hydroxide ions of heavy non-ferrous metals, calcium and magnesium ions. This process was tested in the pilot plant KFM-180 with a raw (untreated) water capacity of up to 18 m3/h per 1 m3 of the flotation cell volume using a mixture of the tailings storage facility and mine water from JSC Safyanovo Copper. The treatment process included raw water treatment with lime, aeration in KFM cells, and filtration in a sorbent bed. The content of metal ions in the treated water is lower than in the feed water by a factor of up to 170,000 and approaches the standards: aluminum 0.016-0.02 mg/l, copper 0.0043-0.0045 mg/l, zinc 0.049-0.052 mg/l. circulating water of Soryin Tailings Storage Facility at JSC Svyatogor. The treatment process included raw water treatment with lime and alkali, aeration in KFM cells, and filtration in a sorbent bed. The content of metals in the treated water is lower than in the feed water by a factor of up to 9000: copper 0.022 mg/l, zinc 0.012 mg/l, iron 0.012 mg/l, manganese 0.015 mg/l, nickel 0.132 mg/l, arsenic 0.016 mg/l. Water hardness is significantly lower: calcium - 12.6 mg/l, magnesium - 1.1 mg/l. This process can be used in the treatment of mine, quarry, tailings storage facility, and circulating water at mining and non-ferrous metals projects."

Jan 1, 2018

By S. Owada

A national project of ?Establishing ?Green-Hydrogen (G-H)? Society in Honjo-Waseda Area? is now being developed by Waseda University together with four other universities and ten companies. The project involves three tasks of technological development of, (1)?G-H? production, (2)?G-H? refining, transportation and storage, and (3)?G-H? utilization. This paper focuses the first task of ?G-H? production from aluminium dross. We developed the physical treatment process by combining selective grinding with vibrating rod mill and electrostatic separation, in order to produce two kinds of materials, one is metal aluminium concentrate to recover it and the other is raw material to produce ?G-H? and aluminium hydroxide which can be generated by the treatment with sodium hydroxide aqueous solution. Here, we described the concentration mechanism of metal aluminium in the selective grinding and electrostatic separation and proposed a separation flowchart for optimizing the ?G-H? system in Honjo-Waseda area.

Jan 1, 2014

By Yimin Zhu, Dezhou Wei, Haijun Liang, Zhifu Zhou

It has been fairly well established by many experiments that Thiobacillus ferrooxidans (T. ferrooxidans), also named Acidithiobacillus ferrooxidans(Kelly and Wood, 2000),can depress the floatability of pyrite. However, the mechanisms governing the process have not been known completely. In the present investigation, wettability and electrokinetic studies were carried out to examine the surface chemical changes on pyrite before and after interaction with T. ferrooxidans or its secretions. Attachment of T. ferrooxidans to pyrite was observed using a scanning electron microscope. The results of experiments showed that, under certain conditions, T. ferrooxidans and its secretions would obviously change the surface electricity of pyrite and result in the iso-electric point of pyrite shifting notably. However, the surface wettability of pyrite hardly changed and its hydrophobicity increased little after interaction with T. ferrooxidans and its secretions. Based on the results of the present investigation it can be reasoned that the depression of floatability of pyrite is due to the reduction of surface free energy, rather than the increase of surface hydrophilicity of pyrite. The decrease of surface free energy weakens the attachment of collector to pyrite; during the process bacterial protein plays the most important role and the bacterial chemotaxis strengthens the effect.

Jan 1, 2003

By Leopoldo Gutierrez, Esau Arinaitwe, Marek Pawlik

"The effect of various polymers, including: anionic carboxymethyl cellulose (CMC), polystyrene sulfonate (PSS), humic acids (HA) and non-ionic hydroxypropyl cellulose, on the wettability of Athabasca bitumen was evaluated through dynamic contact angle measurements using the captive bubble technique. The tests were carried out as a function of pH at a constant ionic strength (0.01 mol/L sodium chloride). The evolution of the three-phase contact angle between the solution, bitumen and an air bubble was followed as a function of time over a period of ~6 minutes. The contact angle data were modelled using a first-order kinetic equation. The results were analyzed in terms of the initial contact angle, the evolution rate constant, and the steady-state contact angle value. In the case of anionic polymers, a pronounced decrease in the initial contact angle value was observed at pH 3. Under acidic conditions, there was no significant effect of CMC observed on the steady-state contact angle value but PSS and HA significantly decreased the steady-state contact angle value. At pH 8.5. the anionic polymers did not affect the wettability of the bitumen surface but they significantly decreased the contact angle evolution rate. These results suggested that CMC is not capable of permanently lowering the hydrophobicity of bitumen, and the polymer only slowed down the evolution of the contact angle to the steady-state value. The results also showed that polystyrene sulfonate and humic acids were capable of making bitumen hydrophilic but only under acidic conditions. Only hydroxypropyl cellulose (HPC) produced a large decrease in the steady-state contact angle under alkaline conditions (pH 8.5). The kinetics of contact angle evolution in the presence of HPC was also drastically lowered. The results were discussed in terms of the chemical composition of the polymers and their different affinities towards the bitumen surface."

Jan 1, 2014

By R. ?. Sherembayeva, ?. ?. ?uktybayeva, ?. B. Rakhimbekova, N. ?. ?m?rova

"Studying the interaction of the phosphorus-containing flotation reagent with the components of the flotation system ""liquid-gas-solid"" during flotation of non-ferrous metal ores allows regulating the enrichment process. The phosphorus-containing reagent-collector anabasinium-O,O-dimethyl-thiophosphate has beensynthesized under laboratory conditions and the concentrated aqueous solution of anabasin hydrochloride and the 40% solution of sodium hydroxide have been used as the raw material. The phosphorus-containing reagent has been obtained by interaction of the anabasine base, sulfur and dimethyl phosphite, due to sulfur and nitrogen atoms it can form complex compounds with heavy metal ions.Studying flotation of copper-sulfide ore of the Sayak field with the use of the phosphorus-containing reagent-collector anabasinium has been performed in the open and closed cycles. The degree of ore grinding was 60- 62% of the class -0.074 mm. There has been established the dependence of the ore flotation parameters on: a) pH of the pulp; b) the consumption of the reagent-collector anabasinium.The effect of the pulp pH on the technological parameters of copper ore flotation has been carried out with a reagent regulator that increases the difference in the surface properties of the minerals to be separated.There has been used lime as the regulator of the medium, the consumption of which varied from 750 to 1500 g/t; the consumption of the reagent-collector anabasinium was 10, 15, 20 and 25 g/t.It has been found that when flotation of copper ore without the use of lime at pH equal to 7.8 and at the reagent consumption, g/t: anabasinium - 25, T-92 - 55, copper recovery in the concentrate is 92.72%, the quality of concentrate is 7, 1%.In flotation according to the factory mode (the consumption of xanthate is 44 g/t, T-92 is 55 g/t, pH = 7.8 (without lime)) of copper ore, copper recovery in the concentrate is 87.38%, the concentrate quality is 7, 97%, with reducing the xanthate consumption to 25 g/t copper recovery is reduced to 83.39%, the quality of the concentrate is up to 6.69%.In the experiments using the factory reagent mode in the closed cycle, with the xanthate mass consumption of 44 g/t, T-92 blowing agent of 55 g/t, the third recleaning concentrate contained 19.13% copper with recovery of 86.89%.Using a phosphorus-containing reagent instead of xanthate with the same flow rate, the third recleaning concentrate with the mass fraction of copper of 19.82% has beenobtained with recovery of 87.77%."

Jan 1, 2018