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By U. M. J. Boin, E. V. Verhoef

Pyrometallurgical reactors constitute a key processing component in the total primary and industrial/recycling resource cycle, being involved both in primary smelting, converting and extraction, as well as the reprocessing of scrap, from aluminium cans to end-of-life automobiles. Therefore the pyrometallurgical reactor?s role in achieving sustainability is the central theme discussed in this paper since optimising their operation minimises waste, residue and offgas (NOx, dioxin, CO2) and maximises product quality and therefore efficiency. To effectively control the overall resource cycle, one needs to take a systems modelling approach of the whole cycle, seeking to also understand the dynamic process behaviour of the individual components of the cycle, and then especially the part that contributes most to the chemical conversion, namely the pyrometallurgical reactor. This paper highlights the role of pyrometallurgical thermodynamics in the whole resource cycle and specifically places equilibrium thermochemistry in the context of process dynamics where large, variable inventories are recycled or maintained within the system. This paper will therefore review the semi-empirical dynamic modelling tools, which are used to model complex systems with the specific goal of developing dynamic predictive models, which also include slag-alloy chemistry, towards controlling the recycling in a feed forward manner. To illustrate the primary production of metals, high carbon ferrochrome and Ni-Cu-matte smelting will be presented as a brief case study. Also fundamental studies in blast furnace and waste incineration kilns will be given. It also will show how the distributed nature of the chemistry of melts in the case of primary extraction, and industrial (recycling) materials such as recycled end-of-life vehicles, have a significant impact on the process outcomes and model predictions. It is therefore argued that the fundamental thermodynamics and kinetics in metallurgical reactors play a final crucial role in modelling the closed material cycle, but only when it is used in conjunction with process systems theory based on reconciled data for parameter estimation and model calibration. System models for aluminium and car recycling will be given as well as a dynamical system model that describes the interconnected material flows for Ag, Au, Bi, Cu, Fe, Ni, Pb, PGM, Sn and Zn for a study on lead-free solder.

Jan 1, 2003

By P. A. Bepswa

A numerical study done to test the efficacy of heuristics developed for the design of measurement networks for high precision metallurgical accounting is presented in this paper. The heuristics considered were designed to maximise variance reduction of terminal stream measurements through data reconciliation for observable linear flow systems. A complex metallurgical process flow sheet from the mineral sands industry was used as a case study. Monte Carlo type simulations coupled with a non-linear programming based steady state data reconciliation algorithm were used as tools to investigate the heuristics. The results obtained suggested a close correlation between magnitudes of measured variances and the respective levels of variance reduction obtained through data reconciliation for both internal and terminal streams. It was observed that variance reduction through data reconciliation was maximised for terminal stream measurements in networks characterised by high precision measurement of internal streams and/or in flow sheets characterised by high ?stream to node ratios?. Terminal streams attached to highly interconnected parent nodes were observed to experience higher reductions in variance compared to terminal streams attached to less interconnected parent nodes. The results generally highlight the additional benefits of highly interconnected flow sheets and high precision internal stream measurement regimes on the maximisation of variance reduction of terminal stream measurements through data reconciliation. These findings are significant to metallurgical accounting and to process accounting applications in general in that they provide a conceptual basis for design decision making regarding the construction of measurement networks aimed at maximising variance reduction of targeted streams through data reconciliation.

Jan 1, 2014

By H. R. Manouchehri

"In mining and minerals industry, except profitability, there are some crucial factors that represent components in economic machinery of a mine and related activities. These are sustainability and minimizing environmental impact factor. Environmental concerns combined with the water and energy availability and related costs, as well as public license to operate all contrive to demand for more efforts targeting sustainability. Mining industry is highly energy-intensive (estimated to consume 6-7% of total world’s energy), with varying the energy efficiency across the industry resulting in significant costs. Size reduction is the main energy consumer contributing to almost 50% of the total energy used in mining. That means efforts must be made to introduce energy efficient comminution flow-sheets and machineries for sustainable development. Since the crushers are more energy efficient than mills, it is logic to push down-sizing in crushing stage(s) as far as technically possible. That has been strategy for Sandvik Mining and Rock Technology in supplying advanced and effective crushers to provide fine crushed product for subsequent milling stage. Lowering the energy consumption and related costs as well as increasing throughput have been the main objectives in design and development of comminution circuits and related machineries. Inefficiency in comminution technology, particularly in grinding, has long been regarded as a major area for investigation and development, especially when production of fines and ultra-fines are considered. In an attempt to explore the potential of fine crushing and its effects on subsequent milling process the fine crushing performance of Sandvik’s conventional cone crusher and Vertical Shaft Impactor (VSI) in pilot scale to define the energy consumption and circulating load in fine crushing. Tests were conducted to obtain fine crushed products at P = 2 mm in a close circuit. Furthermore, the crushed products were characterized and compared by grind-ability, morphology, and surface area measurement tests. Finally, the energy consumption to grind the crushed products to specific grind size was calculated."

Jan 1, 2018

By R. Mukherjee

Consistency of Run-Off-Mine (ROM) quality plays an important role in mineral processing which is not very often talked about. The major impediment is limitation of sampling ROM ore, which makes processing plants to run without any realtime feedback on ore quality that comes in. The process of direct determination of Run-Off-Mine (ROM) ore quality is expensive and time consuming as drawing and preparing representative samples from blasted muckpiles are constrained by large sample size and inherent heterogeneity in terms of size and chemistry. In absence of techniques for direct measurement of quality, monitoring and control of ROM, feed to the processing plant at Joda East Mine, like all other iron ore beneficiation plants worldwide, is largely based on blasthole sampling and subsequent chemical analyses of blastcone chips. While such indirect methods proves to be more accurate for representing whole of a mining block or blasted muckpile (~30-50KT/blast), it is indeed a challenge to ascertain and predict day to day input quality for a part there off. This eventually leads to a gap between predicted and actual ROM quality, resulting in difficulties in process control, in turn, and leading to wide swings in product quality. Hence, it is imperative to bridge the gap between predicted and actual ROM quality by arriving at means, which ensure consistent plant feed grade to deliver consistent output. The paper discusses an efficient and affordable alternative for effective prediction of ROM alumina which has been developed by integrating blasthole quality database in GPS based Truck Dispatch System (GPS-TDS) at Joda East Mine. Initially, GPS-TDS has been installed for optimizing production parameters only, but this development has helped in further utilization of GPS-TDS for real time quality monitoring by improving ROM grade prediction and scheduling from several ore blocks in active mining areas. Keywords:run-off-mine (ROM), blast hole, feed grade, GPS-TDS

Sep 1, 2012

By Bhargav Dhavala, Sristy Raj, Ashok Kumar, Suman Krishna Sit, Adity Ganguly, D. P. Chakraborty

"Tatasteel’s West Bokaro washery#3 is designed to deslime raw coal at 0.5mm; the oversize (+0.5mm) is beneficiated in dense media cyclones (DMC) while the undersize (-0.5mm) is beneficiated in froth flotation (FF) cells. Nearly, 80% of the raw coal feed reports to the DMC circuit consisting of four parallel streams. Presently, the performance of DMCs at washery#3 is interpreted by: (a) comparing the actual plant yield w.r.t the lab predicted yield and (b) misplacement of clean coal to middllings.However, the comparison between actual & lab predicted yield is fallacious given the fact that the lab predicts yield of the borehole sample while the feed received at the plant has different characteristics altogether due to the dilution during mining. To mitigate the said limitations, a quick diagnosis tool using the past data has been developed that will give a prediction of performance of different coal seams in the DMCs, inputs being feed ash to DMCs and stream wise feed specific gravity (coal & magnetite combined).The tool also will help in identifying the root cause on real time basis thereby helping the operator to take necessary corrective actions. The operator can intimate the mining personnel in cases of shale reporting to the feed as a result of dilution during mining. In events of higher standard deviations between the parallel streams w.r.t feed specific gravity, the operator can adjust the parameters accordingly to minimize the yield loss. INTRODUCTION West Bokaro came into existence in 1948, as an independent coal company, managed by M/S Anderson Wright. Tata Steel acquired the Company in 1956 to meet its requirement of metallurgical grade coal for Iron making. Subsequently, in 1976, it was made a division of Tata Steel. In 1974, when coal mines were nationalized, West Bokaro was exempted as it produced coal only for captive consumption of the Steel Works. The first washery of India was set up in West Bokaro. The business objective of the West Bokaro division is to produce clean coal at optimum cost for captive use in the steel plant of Tata Steel at Jamshedpur. The strategy is to reduce ash with minimum loss of yield so that quality of coal improves and yet the cost is beneficial vis-a vis imported coal. The primary product is the metallurgical grade coal for coke ovens, which converts coal into coke for use in the Blast Furnaces."

Jan 1, 2018

By V. K. Chandaliya

N-Methyl-2-pyrollidone (NMP) has already been proven a good solvent for extraction of coal. It is believed that organic components of coal are likely to be dissolved with the solvolytic power of NMP. During dissolution process, original coal also gets disintegrated and thus helps in further extraction. Coal extraction highly depends on temperature, coal to solvent ratio, N-Methyl-2-pyrollidone (NMP) to Ethylenediamine (EDA) ratio and the size of coal particles. The process has been established in the laboratory. There is no reference available beyond lab scale. In present study, we are running a bench scale plant with 40 kg/batch capacity. Design of experiment was done in such a way that the optimum zone of the process gets evaluated for clean coal having low ash with high yield. Bench scale plant trial was conducted based on optimum zone developed during design of experiments (DOE). From the DOE analysis it was observed that feed size and coal to solvent ratio are important parameters for this process. Total 27 experiments (four factors with 3 level of variation) were designed through Box-Behnken model. It was observed that -0.5 mm feed size of coal, 150 °C extraction temperature, 17:1 NMP to EDA ratio, 1:9 coal to solvent ratio was optimum conditions. The results obtained at optimum conditions are 50% clean coal yield with 5% ash.

Sep 1, 2012

By Herman Mendoza, Luisa Ciriaco

An investigation of the seeding mechanism using heterocoagulation and the Derjaguin - Landau - Verwey - Overbeek (DLVO) theory of two pure minerals is the objective of this study. The seed was silica with modal diameters of 4.529 µm (fine particles) and 5.216 µm (coarse particles) and the test powder was hematite with a modal diameter of 0.883 µm. Parameters included variations in the concentration and particle size of silica. Both particles were first subjected to size determination and settling tests via Stoke’s Law. The silica-hematite system was then suspended in 0.001 M KNO3 electrolyte solutions where pH was adjusted. Afterward, the suspension was agitated and was allowed to settle at different time intervals while obtaining turbidity readings. Results through settling time and turbidity vs. pH graphs indicate that maximum heterocoagulation occurs from pH 2 to 5 while minimum heterocoagulation occurs from pH 6 to 7. At these pH levels the zeta potentials of silica and hematite are negative and positive, respectively. On the contrary, repulsive forces dominate the system from pH 8 to 11 due to the particles’ negative zeta potentials. Furthermore, the attachment of hematite to silica increases when the parameters become larger thereby increasing the effectivity of heterocoagulation at acidic to neutral pH levels.

Jan 1, 2014

Anglo American Platinum practices fine grinding in its processing plants to enhance the liberation of valuable minerals. If the fine particles of valuable minerals generated during fine grinding are not recovered during the flotation process, this could significantly contribute to the overall losses. This study examines the flotability of fine moncheite (PGE mineral) particles in a controlled environment (moncheite size distribution, concentration and liberation). A barren Norite ore ground to 40% and 80% passing 53µm was spiked, with four different size fractions of moncheite (-5, -10+5, -25+10 and -53+25µm) in order to evaluate the effect of particle size on flotation. The investigation also included the effect of energy input and collector dosage on the flotation of two moncheite size fractions, namely -5µm and -10+5µm. The results showed that the moncheite particle size has a significant impact on flotation. Coarse particles (-53+25µm) showed the highest Pt flotation kinetics and overall recoveries. The -5µm size fraction of moncheite could also be recovered by flotation, however, at a lower rate compared to the other size classes investigated. The increased collector dosage of 300g/t at the finer Norite grind of 80% passing 53µm enhanced the flotation rate of the -5µm size fraction of moncheite when compared to the lower collector dosage of 150g/t. The higher energy input during laboratory flotation, at an impeller speed of 1000rpm also increased the flotation rate of the -5µm size range, however, at a lower concentrate grade, when compared to the lower impeller speed of 700rpm. More favourable Pt flotation kinetics data was obtained for the -53 +25µm size fraction of moncheite at the fine Norite grind when compared to the coarse Norite grind. Keywords: flotation, moncheite, particle size, energy input and SIBX

Sep 1, 2012

By Richard K. Komarek, Antonios Zavaliangos, Roman T. Dec

Roller presses are widely utilized in mineral industry for fine milling and compaction. Recently used models are providing only limited information about the material behavior in the roll bite. This paper introduces a 2-dimensional finite element model for analyzing those two basic processes. A pressure-dependent plasticity model with linear elasticity was used as a constitutive model for the particular material. Coulomb friction law was used to describe phenomena on the material/roller surface interface. Two basic roller geometries are considered: smooth (used for milling and compaction) and with cavities, commonly used for briquetting. Comparison of the results obtained from the model with experiment indicates that they are following the general trends of experimental values recorded with laboratory roller presses. It is shown, that the model is suitable to analyze material behavior through all stages of the rolling process: feeding zone, nip region, neutral plane and release section. It can predict pressure, shear stress, slip of the material over the roller surface, material velocity field, failure of the compact during release and the course of other important process variables. This allows the process engineer to gain an improved understanding, leading to a better process and equipment design and control.

Jan 1, 2003

By Per Svedensten

One of the most significant behaviour of a crushing plant is the constant variation in the process. The variation is caused by two major effects. The first and constantly changing is the rock material properties. During operation rock material with different strength and particle size distribution is fed to the plant which makes the performance of the equipment to vary. The second and more slowly changing variation is caused by wear on the processing equipment. These effects must be predicted in order to be able to optimise a crushing plant. This paper demonstrates how Monte Carlo simulation can be utilised to study and operate crush-ing plants. By introducing Monte Carlo simulation the varying process can be study and also optimised. To maintain the optimised process performance supervision is needed. This paper demonstrates how results from the Monte Carlo simulation can be utilised for process supervision. Charts for process measurements can for example be derived. These can then be used to guide decision making and understand how the variation and performance of the plant changes over time.

Jan 1, 2014

By L. S. Gertsch

The production of minerals for human use at locations other than the Earth is expected to ?advance ? human prosperity in ? ways that [do] not compromise the potential prosperity and quality of life of future generations? (Brundtland, 1987); in other words, sustainably. This paper examines the interaction of extra-terrestrial mineral production (ETMP) with the following sustainability imperatives: ? The sustainability of human activities on Earth; ? The sustainability of human activities elsewhere; ? Human survival in general, the ultimate sustainability goal. Some of the consequences of mineral production on Earth are widely considered to decrease the future prosperity and quality of human life. Examples include noxious by-products or wastes and unsettling economic up- and downswings. Moving mineral production activities to extra-terrestrial locations, where appropriate, will decrease many of its deleterious effects. Terrestrial mineral production presently is decreasing in some countries and increasing in others, moving from the cheaper and easier ores to more expensive, difficult materials. When the full costs of maintaining the terrestrial environment in a sustainable manner are included, total mineral pro-duction costs must increase. The cost of extracting mineral products from extra-terrestrial sources will be substantially higher, especially in the initial phases, but as the full costs of terrestrial production increase, at some point in the future (different points for different minerals), the curves will cross (Fig.1). This will occur at different points for different materials, a process whose prediction will be complicated by substitution of cheaper materials for some uses as prices of the original material rise. In summary, mineral products from extra-terrestrial sources will tend to increase the sustainability of human civilization, once steady state has been reached.

Jan 1, 2014

By Steven Wright, Sharif Jahanshahi, Shouyi Sun

"While there is a large industry based on recovering platinum group metals (PGM) from complex sulphide ores containing Cu and Ni, there is little information on the thermodynamics of the matte phase formed on smelting the ore and in particular the behaviour of Pt in the matte.The equilibrium between metallic platinum and industrial mattes was studied in a series of experiments where a small quantity of matte (5g) and platinum foil of 150 µm thickness (0.5 g) were equilibrated in magnesia crucibles at 1400°C under conditions where the oxygen and sulphur partial pressures were fixed.The chemical composition of the phases was determined from EDS analysis using a scanning electron microscope. Line scans were initially used to confirm that the foils had attained a uniform composition across their thickness. The composition of the matte was determined from analysis of an area of matte including the small metallic droplets and dendrites.The results of the equilibrium study are presented in terms of how the oxygen and the sulphur pressure affect the distribution of Pt, between the matte and the alloy foil (Lmatte/alloy). Other variables investigated were matte chemistry, i.e., the Fe content and the temperature. The activities of platinum in the mattes were calculated using a regular solution model describing the activity-composition relationship in the alloy."

Jan 1, 2003

By J. J. Liu

In the Bayer process, control of alumina trihydrate particle size, oxalate stability and morphology and foaming is crucial for improving the yield and quality of alumina trihydrate. One way to economically achieve such control is to employ specifically developed chemical additives, termed, crystal growth modifiers (CGM?s). In this paper, the mechanism of action and practical application of CGM?s in the Bayer process are summarized. The application of CGM additives allows for both enhanced agglomeration and secondary nucleation control, and hence coarsening of the particles. Current research efforts have utilized the information gained from mechanistic studies to enhance the performance of CGM products. It was demonstrated in both laboratory tests and industrial operations that the newly developed CGM formulations have a range of properties with enhanced performance, compared to the current commercial products.

Jan 1, 2014

By E. Pourjenaei, P. Ghobadi

High Pressure Grinding Roll (HPGR) is efficient equipment in comminution process. HPGR could be a good option for preparing ball mill feed at the first stage of grinding due to its high efficiency and low energy consumption. Closing with a screen, these mills are utilizing as one of the principle parts in mineral processing industries, especially for iron ores. Recently, HPGRs are working as primary mills at 4 developing lines in Gol-e-Gohar Iron Ore Processing Complex, Iran. Different mechanism of particle crushing in compare to the other tumbling mills makes the HPGR as certain equipment with its own particular controlling parameters. Hydraulic pressure, roller speed and level of material inside feeding hopper are the most important variables influencing grinding efficiency of the HPGR. To figure out how they impress the process and operation situation, different industrial tests were carried out and the best result (d80 about 8 mm for HPGR discharge) was achieved at 180-190 bar pressure (P), 300 rpm speed (S) and 50% of hopper level (L). It is worth noting that this finding has been observed through past pilot test too. We also used design expert method (DX7 software) to develop the best design and analysis the test results, as well. According to the mechanical restriction of HPGR and process limitation in the plant (based on the industrial results), we adjusted value of each parameter in a logical range. Therefore, 20 industrial tests were conducted, as DX7 recommended, and the various impacts of the parameters and their interaction were identified based on statistical analysis. As the authors expected, it was revealed that after presser, roller speed is a critical variable because of its significant role in residence time of the particles between the rollers. The function below has been determined to explain the relation between different parameters and the response.

Jan 1, 2018

By Leonardo Soto, Fernando Villanueva

"Antofagasta Minerals S.A. (AMSA), for its Centinela District Project, is currently developing, at a first stage, a new 90 ktpd Concentrator Plant incorporating Esperanza Sur (ESP Sur) and Encuentro (ENC) ores. In order to dimension properly main equipment, specifically for grinding circuit, a final decision has been taken using geological and metallurgical (comminution) data from both body ores. Data was analyzed internally within AMSA and its consultants to get a final proposed circuit for further engineering studies. Specific Energy Consumption (SEC) parameter is one of the main key factors for proper dimensioning. To get an accurate value different tests have been made and modelled to ESP Sur and ENC ores. Also, operational data from Esperanza operation has been taken into account due to its similar ore characteristics to ESP Sur ore and incorporated as input data for design. Depending on data, quality and amount, it is possible to estimate accuracy for project investment and risk level, hence investment decision can be taken under good and reliable information."

Jan 1, 2014

In this study, selective flocculating of diaspore using anion macromolecular reagent as flocculant was tested to separate diaspore from alum-silicate minerals. Firstly, the effect of pH on settling behavior of diaspore and kaolinite dispersions has been investigated. The results show that the maximum settling speed of diaspore and kaolinite appeared re-spectively at pH7 and pH3.33 which is close to the point of zero charge (PZC) of diaspore (6.8) and kaolinite(3.5). This result is in well agreement with the double electric layer theory. Secondly, the settling behavior of diaspore and kaolinite particles in different anion flocculant solution have been researched. The results indicate that flocculant solution concentration significantly affect the selectivity and the flocculating performance of anion molecular. In high concentration solution, both diaspore and kaolinite have faster settling rate compared to blank solution. How-ever, in low concentration solution, the anion macromolecular can enhance the settling rate of diaspore remarkably but has no apparent effect on the settling rate of kaolinite. This result suggests that the tested anion flocculant is a promising reagent for de-silica of diasporic bauxite. Lastly, FTIR method was employed to probe the adsorption mechanism of flocculant on diaspore and kaolinite. The results reveal that there are anion flocculant characteristic bands on the spectra of diaspore but no obvious characteristic bands of flocculant on the FTIR spectrum of kaolinite. This result is in good correspondence with settling test.

Jan 1, 2014

By Svetlana Krashenina, Nebojsa Petrovic, Oscar Lopez

"As easily mined gold deposits are becoming increasingly rare, gold producers are turning to the processing of ores with polymetallic and copper mineralization. These base metals can create metallurgical and waste handling/disposal challenges, which can render the project uneconomic. Base metals such as copper compete for the cyanide reagent used to extract gold, necessitating the need to increase cyanide volumes and consequently, cyanide consumption costs. Copper will also stabilize in tailings water as weak acid dissociable cyanide, a form that is both difficult and costly to destruct. SART (sulphidization-acidification-recycling-thickening) process technology can be applied to remove base metal interferences in gold projects. SART breaks the copper-cyanide complex and precipitates the copper as a saleable copper sulphide concentrate. With the copper removed, the cyanide can be regenerated as free cyanide for recycle to the gold recovery process. This improves cyanide utilization efficiency and mitigates copper presence in tailings. Additionally, copper recovery generates an incremental revenue source to further improve project economics. Engineering Dobersek GmbH together with BioteQ developed a SART and AVR testing program to recover cyanide and maximize operational efficiencies at a gold processing plant in Kazakhstan with high cyanide consumption in the leach circuit. Results from on-site testing demonstrated that up to 99.98% of copper can be removed and precipitated as copper sulphide and 60-90% of cyanide can be recovered from the AVR and recycled for leaching, reducing total overall cyanide use. This paper provides an overview of the testing methodology and results together with a discussion on the potential of SART to improve gold production operations to deliver both environmental and economic benefits."

Jan 1, 2014

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

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

Jan 1, 2014

Calcium carbonate has three polymorphs: calcite, aragonite, and vaterite. Needlelike aragonite CaCO3 with a high ratio of length to diameter (aspect ratio) is widely used in plastics, rubber and ceramics as a filler and in pigments and paints as a carrier. This paper investigated the influence of H3PO4 dosage, reaction temperature, CO2 flow rate, and initial Ca(OH)2 concentration on formation of needlelike aragonite CaCO3. It was found that the presence of H3PO4 in Ca(OH)2 suspension resulted in rapid formation of (Ca5(PO4)3(OH)) crystal nuclei, which facilitated nucleation and growth of aragonite CaCO3 on the formed (Ca5(PO4)3(OH)) crystal surfaces. The results revealed that H3PO4 addition of P/Ca of 0. 2~0. 3, high temperature of 75~85 °C, low CO2 flow rate and initial Ca(OH)2 solid concentration of 1. 5 %~5. 6 % are beneficial to formation of aragonite. Well crystallized needlelike aragonite CaCO3 whiskers with length > 20 µm and aspect ratio > 15 were directly synthesized.

Jan 1, 2014

By V. A. Ivanova, T. N. Perunkova, N. O. Dorozhanova, G. V. Mitrofanova

"Oxyethylated compounds are used as reagents-regulators in the flotation of non-sulfide ores, in particular, apatite-containing ores. Thus, the necessary degree of selectivity in the flotation separation of two calcium-containing minerals of apatite and calcite is achieved only by using, in addition to a collector, regulators-reagents from the nonylphenol ethoxylates class. In order to establish the most optimal structures, this paper presents a comparative assessment of the physical-chemical and flotation properties of several classes of oxyethylated compounds - alkylphenol ethoxylates, aliphatic alcohol ethoxylates and oxyethylated carboxylic acid. The authors have studied their dispergating ability with respect to the air phase and calcium soaps of the carboxylic collector. Dependences of foaming properties of regulators on the degree of oxyethylation have been determined. Adsorption isotherms of sodium oleate on apatite and calcite in the presence of regulators have been obtained. It has been shown that the presence of oxyethylated compounds in the solution reduces the amount of the adsorbed fatty acid collector. The influence of the considered classes of regulators on apatite flotation has been studied. The interrelation of flotation properties of oxyethylated compounds and their molecular structure has been established.INTRODUCTION Flotation plays a leading role in complex apatite-containing ores processing. However, two calcium-containing minerals - apatite and calcite, which compose apatite-carbonate ores, are characterized by close flotation properties. Selective separation of these minerals is a difficult task, the solution of which is impossible without using reagents-regulators. One of the ways to ensure the selectivity of the flotation separation of calcium-containing minerals is the use of reagents-depressants such as sodium silicate, starch, cellulose derivatives, and others (Liu et al., 2016; Rao et al., 1989). Another method is the application of nonionic reagent regulators (Filippov et al., 2016; Filippova et al., 2014; Ignatkina, 2017), which contribute to the adsorption of the ion collector (Filippov and Filipova, 2006 Rao and Forssberg, 1997) and stability of formed froth (Sis and Chander, 2003)."

Jan 1, 2018