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By I. Yochev, A. A. Metelev, A. I. Stepanenko, A. P. Purgin, M. G. Viduetsky, A. M. Panshin, I. F. Garifulin

"Pneumatic flotation cells of the KFM series are intended for the concentration of various ores and technogenic materials. The key operating principle of the flotation cells of the KFM series is the preparation of pulp for flotation in blowers, offering the advantage of an accelerated flotation process. This report summarizes the results of the implementation and operation of the KFM cells at Russian and foreign projects in 2015-2017. Their implementation and operation experience confirms the high efficiency of the KFM cells, especially in the head of lead and zinc, copper and zinc, copper flotation processes:head KFM-600 flotation cell recovers from lead-zinc ore (Rudmetal AD modular concentrator) up to 52% of lead in a single stage (without cleaner flotation) in a salable lead head concentrate (grade of up to 76% lead, 2.3% zinc). The flotation cell proved to be much more efficient than originally expected in the process description in the design phase,flotation of the copper-zinc ore from Novo-Shemur deposit (PJSC Svyatogor concentrator) in two KFM- 1400M cells recovers up to 65% of copper and 70% of zinc in a high-grade bulk copper-zinc concentrate containing 12-13% of copper and 25-28% of zinc. The installation of the two cells with a combined capacity of 26 m3 allowed to decommission 4 chambers of FPM-16 pneumomechanical flotation cells with a combined capacity of 64 m3 with a simultaneous increase in the overall ore concentration performancea single KFM-1400M cell (13 m3) recovers from the copper ore from Volkov deposit (PJSC Svyatogor concentrator) 53% of copper into a high-grade copper head concentrate (33.0% of copper). For comparison, the pneumomechanical cell FPM-16 (capacity 16 m3) has almost half as low copper recovery (29.6%) into the head concentrate at a lower grade (30.5% copper)."

Jan 1, 2018

By J. Menuge, G. Barker

"Liberation (QEM-SCAN) and surface chemical (time of flight secondary ion mass spectrometry -ToF-SIMS) analyses have been undertaken on plant Pb circuit flotation samples with the aim of defining the factors resulting in sub-optimal recovery. Lead flotation circuit feed, cleaner concentrate and tails samples were examined on a size-by-size basis using QEM-SCAN. Sulfide minerals accounted for approximately one third of the flotation feed with pyrite making up 16 wt.%, followed by sphalerite (13 wt.%) and galena (3 wt.%). Non-sulfide gangue minerals comprised calcium carbonates calcite (26 wt.%), dolomite (14 wt.%) with quartz, feldspars and barite all contributing > 5 wt.%. QEM-SCAN analysis indicated that liberation was not the primary cause of the poor flotation response. Principal component analysis was applied to the ToF-SIMS data derived from five samples (as for QEM-SCAN plus rougher concentrate and tails) to enable identification of correlated surface chemical components. Although a significant range of correlations were observed we focus here on those that show a discernible pattern throughout the float circuit. It was found that for the flotation feed the surface of galena were largely obscured but where Pb was observed there was a strong correlation to surface Fe. For the rougher and cleaner concentrates the galena surfaces were relatively clean with no correlation to Fe for the rougher concentrate and minor correlation in the cleaner concentrate. However, in the rougher and cleaner tails the clear correlation of galena with Fe was again apparent. These results suggest, in combination with prior studies of pyrite morphology, that the principal factor effecting grade is the rapid oxidation of the framboidal pyrite resulting in the contamination of the galena surface with a high loading of hydrophilic oxidised Fe species, thus depressing flotation."

Jan 1, 2014

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

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

Jan 1, 2014

By Fang Liu, Xin Tan, Zhong-ming Wang, Yan-bo Shang, Jie Zhao

"The flotation separation of sulphides bulk concentrate containing Cu, Zn, Mo and Bi, which was obtained by both table-flotation of gross sand of gravity separation of wolframite and bulk flotation of wolframite slimes using butyl xanthate and oil No. 2, etc., has been conducted by using the cyanide process in the tungsten concentrator. The process has problems of high reagents consumption (25 tonne of cyanide dosage per year) and mineral processing cost (800~1000 RMB reagents cost per tonne of by-product concentrates), high mutual containing loss in the by-product concentrates and serious environmental pollution caused by lots of cyanide-containing wastewater. In order to solve this problem, a new cyanide-free separation technology is studied, which is used to process this sulphides bulk concentrate with 8.68% Cu, 8.98% Zn, 0.26% Mo, 1.58% Bi and 40.12% S. The results of the closed circuit test show that Cu, Zn, Mo and Bi can effectively be separated from this sulphide minerals concentrate by using the reasonable flotation-gravity flowsheet, high-efficiency collectors and regulators simultaneously. The metallurgical recovery and concentrate grade are as follows: molybdenum recovery is 94.63% with 50.62% Mo content; copper recovery is 85.18% with 29.29% Cu content; zinc recovery is 75.92% with 46.49% Zn content; total Bi recovery is 65.08% with 16.86% Bi content. The new technology is an alternative to the cyanide process due to its low cost for reagents, satisfying separation results and economic profits, and solves the problem of environmental pollution caused by the use of large quantities of cyanide. Some important parameters in separating the Cu-Zn-Mo-Bi sulphides concentrate are also introduced in this paper. This study provides pretty good technical support for separating the polymetallic sulphide ores containing Cu, Zn, Mo and Bi by cyanide-free technique."

Jan 1, 2014

By N. Nehoroshev, P. Solozhenkin, N. Voyloshnikova, A. Pshennikov

"Molecular modeling of clusters of major bismuth minerals, Bi2S3, was carried out whereby molecular models of minerals and reagents clusters were created. Their HOMO and LUMO energy levels were calculated and using known modelling equations, the absolute hardness ?, eV and electronegativity were calculated. The charges of separate atoms of clusters and the change of properties of the minerals were determined which allowed predictions of the flotation properties of raw ores containing rare bismuth minerals. Modeled complexes containing the clusters of minerals and various collectors were constructed, consisting of atoms and bonds within clusters of minerals. Major physical and chemical parameters were determined for the complexes created, including the total and electronic energy. Based on the energy calculations, predictions of the collector efficiency were proposed. The efficiency of collector was established for various thiolic reagents, the compounds of phosphorus (III) and mixtures of reagents. Theoretical results were checked and confirmed against laboratory ore flotation tests. A gold-bismuth-magnetite ore type was studied where gold, bismuth and iron (magnetite) are of industrial interest. The ore contains 2.8 g/t Au, 1.0 g/t Ag, 0.26% Bi, 45% Fe and 1.25% As. Sulphide mineralization can be mainly found in the form of pyrrhotite, pyrite and arsenopyrite. Bismuth can be mainly found in the form of bismuthite and native bismuth. Gold is fine. A flow sheet for Zhelezny Kryazh ore treatment was proposed. This flow sheet consists of grinding to 95-98% -74 µm, sulfide flotation with two cleaner with xanthate addition, cyanidation of flotation concentrate and flotation tailings included treatment with with CaO (6 kg, 6 hours), cyanidation (8 hours) and CIL (8+24 hours). Saleable products are gold doré, bismuth and iron concentrate."

Jan 1, 2014

By O. A. Bascur

It is difficult to analyse the economics without an integrated view of mine transactions, stockpile inventories, process flows and assays. The lack of integration of mining and metallurgical information with sufficient detail to analyse and act is a problem. However, to take action requires real time information from manufacturing assets, corrected for gross errors from trucks, shovels, conveyors, faulty sensors, bad instrument calibration. Validation methods use process models to identify inconsistent information in the case of corrupt actionable information. This paper presents new strategies that transform the data into business information for continuous improvement and optimization. This technical presentation will review recent implementations enabling large metallurgical complexes to improve their data quality for overall production and energy management. A competence center emerges as an enabler for implementing operational intelligence. The evolution of Web services to troubleshoot plant information and to collaborate at the enterprise level is presented.

Jan 1, 2014

By Ronel du Plessis, John C. Davidtz, Jan D. Miller

Recent results from electrochemical measurements demonstrate that trithiocarbonate (TTC) collectors are more readily oxidized to their corresponding dithiolates than the dithiocarbonate/xanthate (DTC) collectors. Based on the traditional analysis of collector adsorption, trithiocarbonates might then be expected to be effective for bulk sulfide mineral flotation. Previous bench-scale flotation research had shown that TTC collectors are very effective for the flotation of copper sulfide minerals and PGM (platinum group metal) sulfide minerals. More recently, the TTC collectors were evaluated for auriferous pyrite recovery in benchscale plant scale flotation testing in the United States and in plant tests at Anglogold in South Africa. TTC collectors were also applied in bench-scale testing of a PGM ore. In each case an improved separation efficiency was realized. Fundamental studies at the University of Utah examining the effect of collector structure (functional group, -O-CS2 versus .S-CS2), specifically with respect to auriferous pyrite flotation, are in progress. The effect of collector structure was evaluated with air as well as nitrogen as the flotation gas medium. Experimental techniques utilized included electrochemically controlled contact angle measurements to evaluate mineral hydrophobicity and infrared spectroscopy to explain collector adsorption phenomena at the mineral surface.

Jan 1, 2003

By C. Dorfling, W. A. Rossouw

"Hydrometallurgical processes used for metal recovery from waste printed circuit boards (PCBs) typically involve dismantling, shredding and physical separation prior to successive leaching stages for selective dissolution of different metals. The principles of the physical separation units are well understood, but valuable metal losses of more than 30 % can be incurred during these processing steps. The impact of the physical separation units’ performance on downstream leaching operations have not been defined; this prevents the development of a well-integrated process. The objective of this project was to determine to what extent the base metal leaching behavior depends on the physical separation pre-treatment. PCBs were shredded to 100 % passing 2 mm before physical separation by dense medium separation (DMS) as well as magnetic separation. Batch leaching tests using various concentrations of sulfuric acid were conducted on three feed fractions: (1) shredded PCBs without any physical separation, (2) heavy fraction recovered from DMS, and (3) non-magnetic fraction recovered from the DMS heavy fraction. DMS increased the metal content in the feed from 48 % to 75 % on a mass basis, but 70 % of the gold and 20 % of the copper reported to the light fraction. The application of magnetic separation to the heavy fraction produced by DMS removed 67 % and 61 % of the iron and nickel, respectively, while negligible amounts of non-magnetic metals were removed. Although DMS successfully concentrated the feed and magnetic separation removed the majority of iron and nickel, these steps did not result in any improvement in the rate or extent of copper leaching. Metals generally leached faster when the sulfuric acid concentration was increased from 1 M to 2.5 M; this effect was seen to be more pronounced for pretreated feed. INTRODUCTION The fast rate of technological development has led to a decrease in the service life of electronic devices. This is resulting in an increased rate of electronic waste generation. The recovery of metals from electronic waste is of environmental and economic interest. The majority of these metals are typically located on printed circuit boards (PCBs) within electronic devices (Tuncuk, Stazi et al., 2012). Hydrometallurgical processes are considered a viable option for small scale metal recovery from waste PCBs, and generally involve the following steps: disassembly for removal of hazardous and reusable parts, size reduction, physical separation, successive leaching stages for metal dissolution and finally recovery of metals from leach solutions."

Jan 1, 2018

By I. Yelkin, Erico Tabosa, Alex Jankovic, R. Hayashida, R. Faveere

"The mining industry faces growing challenges from more complex and lower grade deposits, rising costs, limited energy and water availability, and increasing societal pressure to operate more sustainably. Mining operations need to be more efficient, not just to reduce environmental impact, but also to remain economically viable.To maximize profitability and sustainability, existing operations and new projects must consider integration and optimization of all stages of production. A mining operation is essentially a series of inter-connected processes, with the performance and outputs of each stage affecting the subsequent ones. Optimizing stages in isolation can result in sub-optimal overall performance.The industry has long recognized the benefits of holistic optimization using the Mine-to-Mill concept, and there are many well documented successes. However, it is increasingly common to observe operations simply increasing explosive consumption in the mine and expecting optimization of the entire value chain (mining and processing). For true holistic optimization, blast intensity is not necessarily increased, but rather adjusted to best suit the requirements of the different types of ores treated, the circuit configuration and equipment, installed comminution power and the downstream beneficiation processes. It is a fully integrated effort with optimization of many aspects in the mine, comminution and separation processes.To be successful, optimization of the production chain from mine to process requires a site-specific, structured methodology supported by extensive ore characterization, auditing, surveys, data analysis, mathematical modelling simulations and a cost / benefit analysis. Following this methodology, optimization strategies are rapidly identified and implemented considering mine and plant constraints. Management needs to set up appropriate KPIs and site personnel need to be trained for the new operating strategies to be successfully incorporated into site practices and procedures in the production environment. This will ensure the benefits are achieved and maintained. This paper describes the methodology employed by Hatch to improve overall efficiency and profitability from mine to process. Two case study examples at Russian gold operations and benefits achieved are presented."

Jan 1, 2018

By B. Das

The processing of banded iron ore by direct anionic and reverse cationic flotation to produce pellet grade concentrate is investigated. This low-grade iron ore, known as banded hematite quartzite (BHQ) contains 41.8% Fe, 41.5% SiO2, 1.2% Al2O3, and 0.5% LOI. The flotation behavior of BHQ is studied by varying the effect of concentration of collector, frother, dispersant and pH. Oleic acid and dodecylamine are used as the anionic and cationic collectors respectively. The parameters that gave the best results in cell flotation are utilized in 100 mm diameter flotation column. All the results are compared with regard to the iron grade and recovery in concentrate. It is observed that, anionic collector with dispersant dosage of 220 g/ton, at pH ~8.5 is selective and yielded a high-grade iron concentrate with low silica as impurity. Also, it is possible to achieve an iron concentrate with 64% Fe at 30-37% weight recovery. The characterization studies of the BHQ ore using X-ray diffraction (XRD) technique and liberation analysis with QEMSCAN® are carried out. The sample contains 58.8% hematite and 37.7% quartz and the liberation of hematite particles are found to be 90.3% in -25 µm size. An alternative statistical modeling approach called response surface methodology was also undertaken to optimize the operating parameters in order to maximize the iron grade and recovery. The predicted results by the model are in agreement with the experimental values.

Sep 1, 2012

By Xiaoxu Sun, Jianchao Yao, Jiancheng He, Shijie Lu, Hongxi Zhou

"With the trend of increasingly more mineral resources turning low-grade and refractory, more and more new ore bodies being developed worldwide are more finely grained, which drives the rapidly development and application of techniques related to tower mills (vertical spiral stirred mills). However, the lacking in fundamentals of fine grinding, as well as standard procedures for equipment selection and scale up, seriously restraint high efficient application of tower mills. Taking grinding media motion characteristic and grinding intensity as a breakthrough point, this paper studies mechanisms behind how critical parameters affect grinding efficiency of tower mill, including ratio of screw pitch and diameter, agitator rotation speed, grinding media size. Several sets of orthogonal test are conducted on the quartz ore using the grinding system of KLM-3 tower mill. All the tests are under the same character of feeding mineral and undergo the consistent sampling for at least 60min grinding time. The input power is measured by a torque measurement system and the grinding products are analyzed by the laser particle size analyzer. The test results show the influence of parameters on grinding efficiency. Among the three important parameters, the effect of grinding media diameter is the biggest, followed by the agitator tip speed, and finally the ratio of screw pitch and diameter. For the different particle size of grinding products, the best combination of grinding parameters is different, with the mineral size becoming finer, the ratio of screw pitch and diameter become smaller, the diameter of grinding media become smaller, while the agitator tip speed does not change too much. The conclusions of the study help us to improve the grinding efficiency of the tower mill, to assist in the selection and optimization of working parameters, establish new scale up method on the basis of grinding model and eventually provide theoretical basis of rational selections of structural and media physical parameters within tower mill."

Jan 1, 2018

By I. Gombköto, G. Mucsi, S. Nagy, F. Kristály, Á. Rácz, R. Szabó, B. Egyed

"Present paper deals with the investigation of a Hungarian pumice. Grinding experiments were carried out in a stirred media mill for various residence time. Ground samples were tested with laser particle size analyzer to determine and calculate the material fineness (particle size distribution and specific surface area). The lime adsorption capacity was measured to monitor the reactivity. Alkali activated cement paste was prepared using ground pumice with various alkali activators. Cube shaped specimens were produced from the paste and the uniaxial compressive strength was measured at the age of 7 days. The resulted alkali activated material structure was investigated by XRD and FTIR. The results of the experiments show that pumice fineness has strong impact on its hydraulic activity, hence on the compressive strength and the structure of the resulted binder. Relationships between grinding fineness, material structure and strength of the raw and mechanical activated material as well as the alkali activated cement were revealed. INTRODUCTION Pumice is a natural pozzolan which can be used as raw material for cementitious materials in limited portion owing to its low reactivity. Furthermore, due to its mineralogical composition it can be used for developing a new environmental friendly binder, namely alkali activated cements (AAC) which are inorganic alumina-silicate materials with good cementitious properties (Almalkawi et al., 2017; Özodabas and Yilmaz, 2013; Najimi et al. 2018; Yadollahi et al., 2015). Despite being a rather recent research topic, many papers and books have been published focusing on various aspects of alkali activation. There is great variety of raw materials that can be utilized for AAC production. However, primary raw materials are very expensive and secondary materials are heterogenous in composition. Therefore, a more homogeneous and low price silicate would help to balance the properties and cost of resulting cement and easing the way for commercialization of AAC. However, the control of its reactivity is of great importance which can be realized using mechanical activation by grinding (Juhász and Opoczky, 1990; Djobo et al., 2016; Mádai et al., 2015). The goal of present paper is to investigate the effect of mechanical activation of pumice on the properties of the resulted alkali activated cement."

Jan 1, 2018

By Junwei Han, Kai Xue, Wenqing Qin, Tan Xu, Fen Jiao, Lianbing Cai, Wei Liu

"The research aimed at solving the problem of the stacked spent magnesia-chrome refractories using in non-ferrous metal smelters, which contain various heavy metals and are considered as a hazardous waste. The purpose of the research is to recycle the spent refractories environmentally and economically using gravity separation and flotation to obtain metal concentrates for smelting and using chloridizing volatilization to remove the trace metals from tailings, providing raw material to reprocess magnesia-chrome refractories. In the course of the study, laboratory techniques for the preparation of experimental samples of spent magnesia-chrome refractories were developed including the sequence of operations of material grinding, gravity separation, tails regrinding, flotation, filtration and subsequent unification of concentrates, filtration and chloridizing volatilization of tails, and collection of volatiles. Laboratory tests carried out on several types of samples of spent magnesia-chrome refractories from different smelters showed that gravity separation provided increase in quality of concentrates including about 80% metals (including Ag, Pb, Bi) and flotation separation provided increase in recovery of concentrates under the condition of 200g/t of emulsified kerosene, and 500g/t of combined collector. Based on combined technology of gravity and flotation separation, about 90% metals were recovered from the refractories by a closed-circuit test and the total concentrates contained 40% metals, which can be returned to smelting process as a feeding. Because a small amount of metal in raw materials will seriously affect the performance of refractories, chloridizing volatilization is necessary for removing the remaining 10% metals from tails mixed 8% coke and 13% magnesium chloride at a temperature of 1200°C. Thus, the tailings can be reused as a raw material for new refractories.INTRODUCTION Magnesia-chrome refractory has been used extensively in various industries such as secondary metallurgy, non-ferrous furnaces and cement making due to their high temperature stability, low thermal expansion and outstanding erosion-corrosion performance at high temperatures (Gotod et al., 2005; Vezza et al., 1997; Gregurek et al., 2015). Generally, the magnesia-chrome refractories are produced from a mixture of magnesia and massive variety of chrome ores. However, massive chrome ores are being depleted throughout the world. Even more serious is that the heavy metal chromium (Cr) can transfer into soil and water, which will have an influence on the survival and development of human beings (Zhao et al., 2006; Jiang et al., 2004; Qintie et al., 2013). As a result, regulations treating spent magnesia-chrome refractories as potentially hazardous waste are being enforced, making their disposal difficult and expensive."

Jan 1, 2018

The traditional technological flow sheets for processing of ferrous quartzite (magnetite ores) al-low production of the iron concentrates with Fe content of 65%~68 % and recovery level about 55 %. The losses of iron with the tails of wet magnetic separation are related to hematite and quartz-magnetite particles, which are not extracted under low magnetic field employed. This work presents the results of the application of reverse cationic flotation for production of hematite concentrates with weak silica content from the tailings of wet magnetic separation of mag-netite. Fine particle size, complex mineralogy and presence of locked particles determine the impos-sibility of direct production of hematite concentrate by flotation or magnetic separation. The gravity concentration allows obtaining of iron concentrate from the well-prepared feed (size fraction -53+20 µm) but with very low recovery. Thus, hematite concentrates with weak silica content and satisfactory iron recovery were obtained by reverse cationic flotation, when it was fed with iron pre-concentrate produced by high gradient magnetic separation. The best flotation results were obtained by the use of formulations based on amines of different molecular structure that modulate the structure of adsorption layer, and favour a shifting of hydro-philic-hydrophobic balance on the surface of silicates with adsorbed starch and their preferential transfer into the froth product.

Jan 1, 2014

By Jingzhong Kuang, Zheyu Huang, Chuanzhou Guo, Pengfei Liu

"In this paper, scheelite and scheelite coated with Pb2+ (SC) were synthesized by chemical precipitation with the help of ultrasonic. The role of the Pb2+ on scheelite was evaluated. Additionally, the dissolution behavior of minerals and the adsorption mechanism of collectors were investigated systematically via SEM, XRD, EDS. The results indicate that the ultrasonic cavitation can promote the formation of scheelite with large particle size and high crystallinity. Due to the exchange of WO4 2- and OH-, the dissolution of scheelite are not in a 1:1 equivalent amount by chemical formula and the concentration of WO4 2- is higher than that of Ca2+ in the solution because Pb2+ promotes the transfer of WO4 2- from scheelite surface into the solution. The dissolution of scheelite is an endothermic reaction and its enthalpy reaches the maximum value of 692.59J·mol-1 at pH=8~10. But the coating of Pb2+ changes the thermal effect of scheelite in the solution and the dissolution of SC is an exothermic reaction with the dissolution enthalpy of -262.30 J·mol-1. At pH=8~10, the adsorption capacity of sodium oleate and salicylhydroxamic acid on the surface of SC is higher than that of scheelite which delivers that Pb2+ contributes to the scheelite surface dissolution and enhances the adsorption of collectors on the mineral surface, thus achieving activation.INTRODUCTIONIn modern society, tungsten is a type of quite important rare metal and also a strategic resource. Because of its low vapor pressure, high melting point, good electrical and thermal conductivity properties, it is widely applied in high-temperature technology, lighting, machine and engine construction (Zhao,Z.W, 2013; Yan, W, 2017; Ilhan, S, 2013). Both scheelite and wolframite are the major tungsten deposits. With the depletion of easily-processed wolframite, scheelite has drawn a great deal of scientific and industrial attention. Scheelite can be recovered by flotation due to the metathesis of polarity and chargeability on minerals surface via adding regulators and collectors."

Jan 1, 2018

By M. A. Wei

Effects due to some metal cations, such as Ca2+, Mg2+,Fe2+, Fe3+, Cu+, Cu2+, Zn2+ and Al3+ etc., which are produced in the pulp when the complicated ore is dipped in the deioned water, on the flotation of chalcopyrite and galena with the isopropyl thionocarbamate as collector have been studied. It is found that chalcopyrite floatability is not influenced by these cations, and the cations can be di-vided into three types according to their effects on the purified galena?s floatability with the same conditions, as activator such as Cu+; as depressant such as Al3+, Fe3+, Fe2+, Zn2+ and Cu2+ , unaffective such as Mg2+ and Ca2+.

Jan 1, 2014

By Tatyana A. Ivanova, Tamara N. Matveyeva, Anatoliy A. Fedorov, Tatyana V. Nedosekina, Valentin A. Chanturiya

An ingenious methodology purposively developed by the authors for comprehensive assessment of flotation properties, electrophysical characteristics and. crystal chemistry features of natural gold-bearing sulfide minerals of different origin has been used in this study. Examination of the elemental composition of the minerals, ion-molecular components of the liquid phase in suspensions, surface properties of sulfides and different flotation reagents sorption forms was performed using the methods of X-ray phase and spectral analysis, potentiometry, UV and IR spectrometry, computer image analysis, and computer simulation techniques. The role of isomorphous impurities in the formation of hydrophobic sulfhydric collector layers on mineral surfaces in complex ore processing has been elucidated. The parameters characterizing the variability of the Fe:S ratio in pyrite of different origin have been determined based on non-stoichiometry characteristics of natural gold-bearing sulfide crystals. An ingenious method of formatting and linear approximation of experimental data was used to find out the quantitative relationships between the impurity content, electrophysical characteristics, non-stoichiometry and floatability of pyrite from a number of different deposits. The effect of the impurity species present in sulfides on the characteristic pH value marking the floatability peaks as such and their trend of shift towards higher alkalinity has been revealed. A theoretical substantiation has been given to prognostic assessment criteria for processing characteristics of gold-bearing sulfide minerals with varying composition. New flotation reagents and advanced reagent systems which help to increase the contrast of processing characteristics for different gold-bearing sulfides, resulting in improved selectivity, have been developed. The mechanism of selective flotation of precious metal-bearing Fe and As sulfides achieved by using short-chain dithiocarbamates and a mixture of cyclic trithiocarbonate with oxyalkylsulfides has been analyzed.

Jan 1, 2003

By Q. Zhang

This paper, by studying the surface properties of pure dolomite minerals separated from representative marine sedimentary rare earth-bearing phosphate ores in Zhijin, Guizhou, aims to study the effect of different anions on the ? potential of dolomite. The research findings showed that the dolomite mineral had a point of zero charge (PZC) at pH 6.5, and the PZC shifted towards lower pH values with addition of anion SiO32- and PO43-. However, addition of anion CO32- and F- resulted in higher PZC values. Keywords: dolomite, ? potential, PZC, anion

Sep 1, 2012

By B. Rezai

Impeller speed and air flow rate are two influence parameters on coarse particles flotation and collision and attachment angles. So, in this research recovery of quartz particles at four diameter classes carried out and collision and attachment angles investigated. It is found that maximum flotation response was observed at Impeller speed of 1100 rpm and 15 L/h air flow rate. For either more quiescent (Impeller speed<1100 rpm) or more turbulent conditions, flotation recovery decreased steadily. Furthermore, amount of attachment probabilities is calculated using suitable equation. According to this study, with decreasing particle size, air flow rate and impeller speed, probability of attachment increased and with increasing contact angle, probability of attachment increased. For various air flow rates, impeller speed and particle size, collision angle has been calculated. Maximum collision angle obtained at with 15 L/h air flow rate, particle size of 256 µm and impeller speed of 700 rpm and minimum collision angle obtained at with 45 L/h air flow rate, particle size of 545µm and impeller speed of 1300 rpm. In this study, maximum attachment angle, , was around 75 L/h air flow rate, particle size of 256 µm, contact angle of and impeller speed of 1300 rpm and minimum attachment angle was with 15 L/h air flow rate, particle size of 545 µm, contact angle of and impeller speed of 1300 rpm. ?82.72 ?64 cr??33.39 ?90 ?13.0 ?60

Jan 1, 2014

By Arkady Senchenko, Yury Kulikov

"Basic theoretical grounds of the methods applied for crushing and grinding parameters determination according to international standards are given in this paper. Statistical data about crushability and grindability research are shown. The potential relationship between the values of Fred Bond Work indices and John Starkey indices (Crushing index, Ball mill index, Rod mill index and AG/SAG index) are discussed in this paper. In order to establish correlation between the crushability and grindability indices the analysis of over 2 500 tests for 165 deposits located in different parts of the world was performed. The relationships among different types of energy consumed for crushing and grinding were determined. A method for preliminary estimation of energy consumption in semiautogenous + ball mill grinding circuit is suggested for its application in preliminary technological solutions development and technical-and-economic assessment."

Jan 1, 2014