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By Turgay Gurun

"Digital simulation can be used as an analytical tool to optimize the design of crushing plants without need for large-scale experimental programs.General mathematical description of a crushing operation permits the simulation of a crushing plant flowsheet under various operating conditions. The process model encompasses multistage open- and closed-circuit crushing of hard and soft rock. Crushing balances are analyzed in the light of crusher and screen performance and a comparison of different closed-circuit arrangements is made in terms of process and layout criteria.The simulation model allows comparison of process alternatives to be made in terms of equipment selection and capital and operating cost estimation. It thus provides the pertinent practical information to maximize plant efficiency, and to minimize expenditures in such items as equipment, structures, power consumption, and so on."

Jan 1, 2014

By T. Gerritsen, R. MacRosty, R. Pula

For several years Hatch has been installing fibre optic temperature sensors on the copper cooling elements of smelting furnaces to improve monitoring capabilities in critical locations. The metal/matte tapblock is a key area to monitor in the furnace as it undergoes severe wear from the molten material repeatedly drained through it. The high wear rate around the tapblock means downtime is necessary to perform refractory repairs. A good understanding of the tapblock condition allows the operation to maximize safety and production; consequently the metal/matte tapblocks have been the focus of this study. Fibre optic technology allows the installation of numerous sensors in locations that are very sensitive to refractory thickness, thereby providing information previously unavailable with traditional measurements. The transient nature of the thermal response to tapping and the three-dimensional geometry of the tapblock confound the interpretation of refractory thickness from temperature measurements. This paper focuses on the analysis of both plant data and thermal modelling simulations and details the progress made in relating the temperature measurements to the refractory thickness in front of the copper tapblock.

Jan 1, 2014

By J. K. Williams, M. P. Wells

"As part of the planning system at each division of Nchanga Consolidated Copper Mines, Limited, the Mine Planning Department is required to produce a detailed production schedule for each shaft.Because of the difficulties in producing a schedule which satisfies all the mining constraints, and because of the large clerical effort involved, the full range of possible schedules can never be considered.It has been found possible to produce a schedule using linear programming which satisfies the majority of the many varied mining constraints. Computer programs have been written to enable the mine planning department to use this mathematical system without assistance.The system has a large degree of flexibility to enable the planner to include conditions which cannot be incorporated readily in the linear program. This system permits the more efficient production and evaluation of schedules and reduces the amount of clerical effort."

Jan 1, 2014

By Adriaan van Seters

"Abstract The content of Eurocode 7 – Part 1 and Part 2 – with respect to piled foundations is outlined. The important role of pile testing is presented and the derivation of the characteristic value of pile bearing resistance is explained. Recommendations for the use of correlation factors are given. The ongoing work of the Evolution Groups on piling is to prepare a revision of Eurocode 7 after 2019. Future topics and changes are highlighted.General outline of pile design by Eurocode 7In his paper for this conference Frank (2014) outlined the various aspects of standardisation for pile foundations, which involves Eurocode 7 as leading for pile construction in Europe. Standards for pile testing and execution of piling works were established in the last 15 years.This paper focuses on the design of piled foundations according to the design code Eurocode 7, which consists of 2 parts:EN 1997-1 Geotechnical design - Part 1: General Rules (CEN, 2004);EN 1997-2 Geotechnical design – Part 2: Ground investigation and testing (CEN, 2007) In Eurocode 7-1, Section 7 – Pile Foundations - deals with the design of piles. The safety concept for pile design is given in Section 2 – Basis of Geotechnical Design - for the three Design Approaches.In Section 7 presents the design of piles according to four methods:1. Results of static load tests2. Empirical or analytical calculation methods3. Results of dynamic load tests4. Observed performance of a comparable pile foundation.Guidelines for the ground investigation for piles is provided in Eurocode 7-2, Annex B.3. In the Annexes of Eurocode 7-2 examples of analytical methods to determine the bearing resistance of a single pile based on the results of various ground investigation techniques are given. Thus calculation models are presented based on design using the results of Cone Penetration Tests (D.6 and D.7) and Pressuremeter Tests (E.3). The Annexes of Eurocode 7-2 are informative.For the interpretation of Eurocode 7, reference is made to Frank et al (2004) and Bond and Harris(2008)."

Jan 1, 2014

By Tamara Matveyeva, Tatiana Ivanova, Nadezhda Gromova

"The paper presents the results of study of the sorption and flotation properties of the reagents of plant origin - tannin and natural extracts of the oak bark and stems of plants, with a view to their application as a low-cost environmentally friendly modifiers of iron sulfide flotation for the recovery of minerals containing precious metals. The technique of preparation of plant extracts with a fixed content of extractable tannins has been developed.The mechanism of flotation reaction of tannin extracts has been identified as based on their adsorption on the surface of pyrrhotite and arsenopyrite to form strong complexes with iron (III) at concentrations below micelle concentration. It has been found that adsorption of plant extracts occurs without displacement of primarily adsorbed xanthate, and preliminary adsorption of xanthate did not preclude fixation of tannin on the mineral surface.It has been shown that plant extracts having hydrophilizing properties at low concentrations could be applied as selective depressants for pyrite, pyrrhotite and arsenopyrite in a weakly acidic, neutral or weakly alkaline medium. The use of plant modifiers could help to increase the quality of gold- and platinumcontaining concentrates and reduce the ecological impact on the environment."

Jan 1, 2014

By Yiling Zhang, Paul A. Salvador, Gregory S. Rohrer

"Photocatalysis utilizes solar energy to produce hydrogen by splitting H2O. When a thin film of photocatalyst TiO2 is supported on a ferroelectric BiFeO3 substrate (band gap ~2.5 eV), the TiO2/BiFeO3 heterostructure is capable of photochemically reducing Ag+ to Ag0 in aqueous solutions under blue light with enhanced efficiency. The observation of spatially selective silver patterns on surface of the heterostructure after reaction suggests that photogenerated electrons and holes in ferroelectric BiFeO3 are driven in opposite directions to reduce their chance of recombination. Comparisons of the amounts of reduced silver on TiO2 film grains with distinct phases/orientations show that the reactivity is mildly preferential on anatase TiO2 phase and does not strongly depend on crystallographic orientation of BiFeO3.IntroductionTitania (TiO2) is capable of photocatalytically converting H2O to hydrogen and oxygen under the irradiation of ultraviolet light. [1, 2] One of the limiting factors for titania to be used as an effective photocatalyst is its band gap. Because the absorption edges of rutile and anatase titania are at 3.0 eV and 3.2 eV, respectively, they can only absorb light in the UV portion of the spectrum, which is about 3% of the available solar energy. [3-5] This limitation has motivated attempts to modify the absorption edge of titania so that it can absorb visible light.One strategy is to substitute a portion of the titanium and/or the oxygen with other atoms. There are numerous reports on visible light absorption of titania by doping and co-doping of Cr, V, Mo, Sb, Fe, N, S, C, and F. [6-34] Another strategy is to add an adsorbed molecular species that absorb visible light and donate an electron or hole to the titania, such as organic dyes [33, 35, 36] and Ce3+/Ce4+. [37, 38]The strategy in the present work takes the approach of depositing a pure titania thin film on a visible light absorbing substrate BiFeO3 to induce visible light activity of the heterostructure. BiFeO3 is a semiconductor with a band gap of about 2.5 eV [39-41] and is photocatalytically active in visible light. [42, 43] It is also ferroelectric with spontaneous polarization along pseudo-cubic <111> directions of 6.1 µC cm-2. [44] The spontaneous polarization gives rise to internal electric fields that drive photogenerated charge carriers, namely electrons and holes, in opposite directions to reduce their chance of recombination. [45-47] Additionally, the separation of electrons and holes leads to the spatial separation of reduction and oxidation half reactions so that the back reaction of intermediates is also suppressed. Such charge carrier separation has been reported in TiO2/BaTiO3 heterostructures with UV light illumination. [48-51] The TiO2/BiFeO3 heterostructures in this work combine both advantages of the relatively narrow band gap and the internal fields in BiFeO3 to enhance the overall photocatalytic activity."

Jan 1, 2014

By Joseph Daly

This is the detailed evaluation of the establishment and implementation of an ‘oil recycle plant’ located on site at Boggabri Mine NSW, (Australia); its production, its use and its value. Also discussed in detail is the quality of the raw material produced, and the process and initial application of this raw material generated as well as the analysis of such, as a component within bulk explosive as applied to the mining industry as compiled during analysis. Laboratory analysis prior to field testing is also discussed including independent external laboratory analysis as well as the environmental benefits and a business case for recycled oil in blasting. This paper includes technical details of the product including densities, velocity of detonation and other associated key performance indicators. The intention is to off-set the amount of Distillate (Diesel) utilised as a component of bulk explosives, with a raw recycled oil and thus reducing both the environmental carbon footprint as well as production costs with regard to introduced petrochemical production and utilisation; an oil that is an existing recourse of controlled waste not only difficult but expensive to otherwise dispose of, whilst keeping the entire process ‘on-site’. Though recycled oil in blasting is not an entirely original idea, the key feature of this paper is the ability to complete the entire process on-site.

Jan 1, 2014

By N. Henderson, J. Weyer, J. F. Brune

"The mining industry worldwide is currently facing a significant restructuring process. In most underground mines, widespread mechanization of the mining processes increases production while reducing staff numbers. At the same time, mining depths as well as the lateral spread of the mine workings are increasing. This ever-changing mining environment requires sophisticated solutions for the design and operation of underground mines. In fact, a reduced number of mining engineers is taking responsibility for everincreasing mine operations. This applies not only to the excavation of the minerals, but also to all other aspects of the mining operation, including health and safety, disaster management, and mine rescue organization.Most mining engineering graduates entering the industry lack experience in mine emergency management. Young engineer trainees must learn mine emergency management and rescue work in addition to their normal training experience on the job. Often, and unfortunately, emergency and rescue training at different mining companies is not carried out to the highest level and standard and with the best possible training outcomes. The tasks and challenges a young engineer faces while being trained in a new position do not leave much room for additional training in mine rescue and emergency management. At the same time, experienced, ’old hands’ are retiring and cannot easily be replaced due to limited graduation numbers.Strategies are being developed at mining universities worldwide to train mining engineering students in handling mine emergency situations and to provide hands-on experience for managing potential accident and disaster scenarios underground. Two of these strategies, from the USA and from Central Europe, are presented in this paper. These specific strategies have to be seen under special consideration of the local and regional boundary conditions, but might serve as case studies for mining schools and universities in other countries."

Jan 1, 2014

By Peng Zhang

In previous research, the laminated overburden model from the LaModel program was effectively integrated with Analysis of Retreat Mining Pillar Stability (ARMPS) through ARMPS-like input to create a laboratory version of the new ?ARMPS-LAM? program. This program takes the basic ARMPS geometric input for defining the mining plan and loading condition, and then automatically develops, grids, runs, and analyzes a full LaModel analysis of the mining geometry to output the section stability factor (SF), all without further user input. The initial ARMPS-LAM results were encouraging with a case history classification accuracy of 55% to 71%; however, a few of the input variables that were nominally included in the SF calculation showed independent significance in the classification accuracy. Therefore, in order to further improve the accuracy of the ARMPS-LAM program, an investigation of the SFs calculated by the new ARMPS-LAM program and the ARMPS program is detailed in this paper. The initial results of a linear correlation between the ARMPS-LAM SF and the ARMPS SF showed a strong correlation (R2 = 0.88), with the ARMPS-LAM SF averaging about 8% higher. The difference in SFs between the programs were further investigated, and, ultimately, the results indicated that the laminated overburden model as implemented in ARMPS-LAM distributes relatively more load on the section pillars for depths less than about 1,000 ft and less load for depths more than 1,000 ft. The results of this research highlight the potential for improving the ARMPS-LAM program in the future by implementing a more accurate loading calculation on the section pillars.

Jan 1, 2014

By William Skinner, Jonas Addai-Mensah, Keith Quast, David Robinson, Jason Connor

A review of the laboratory- and pilot plant-scale physical separation techniques for the beneficiation of nickel (Ni) laterites shows limited efficacy. To date, the only upgrade technique adopted commercially, prior to hydrometallurgical processing of Ni laterites, is the removal of a barren, coarse size fraction in the feed by classification. In the present work we investigated two low grade (~ 1%), goethite-rich Ni laterite ores’ upgrading by magnetic separation, attritioning/coarse, (lower Ni-grade) gangue rejection and flotation techniques. Low intensity (0.1T) dry magnetic separation at ambient temperature of raw samples and those pre-heated at temperatures up to 450 °C showed evidence of pay metal Co and Mn bearing asbolane and/or lithiophorite minerals pre-concentration in the magnetic fractions. Ni distribution, however, did not show any noticeable magnetic upgrade but followed the weight distribution. Other ore pre-treatment methods (e.g., desliming and sulphidisation) followed by froth flotation with anionic and cationic reagents also led to noticeable (~35%) Ni upgrade. This is due to the deportment of Ni across several gangue host mineral phases (i.e. Fe oxide/hydroxide and a range of silicate/aluminosilicate minerals). From chemical analysis, after disaggregation of ~ 1% Ni grade feed ore, coarse (-600 + 38 µm) and fine (-38 µm) fractions of ~0.6% and 1.3% Ni grades respectively, were also produced, suggesting that a significant upgrade in Ni content can be achieved by rejecting the + 38 µm fraction with the loss of <40% of the Ni. The ore mineralogy, particularly the complexity and high number of un-liberated Ni-bearing phases, greatly compromises physical separation methods for these ores, with the possible exception of screening after disaggregation of the fines inherent in the run of mine ores.

Jan 1, 2014

By Shinji Sassa, Naoki Takahashi, Eiji Kohama, Wakaki Tsuda, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"Abstract Deep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. Column-type solidification, however, has been thought to have little effect as a liquefaction countermeasure, because the shear deformation of unimproved soil between the columns cannot be reduced. In recent years, experimental results have been reported that imply that solidified columns can reduce the shear deformation of unimproved soil around them. A new arrangement has been proposed to mitigate lateral flow induced by liquefaction. In this study, a series of dynamic centrifuge model tests was conducted to verify the lateral flow resistance of stabilized columns. The results indicate that stabilized columns can reduce the lateral flow of liquefied ground if the column displacement and the column head rotation are restricted. This paper concludes that it is important to restrict the displacement and the rotation of the column head by surface improvement to mitigate the lateral flow of liquefied ground.INTRODUCTIONDeep mixing method has been employed increasingly in recent years as a countermeasure against subsoil liquefaction. The solidified body formed by the deep mixing method is usually block or lattice shape, composed of solidified columns that overlap each other horizontally. Lattice-type solidification has been shown to be effective as a liquefaction countermeasure despite the presence of unimproved soil inside the lattice wall, because the shear deformation of the interior soil is restrained by the wall (Suzuki et al., 1989). On the other hand, it has been thought that column-type solidification cannot reduce shear deformation of unimproved soil around columns, because the displacement of a solidified column is less restricted than that of a lattice wall. Column-type solidification has been reported to have little effect as a liquefaction countermeasure, but to be superior in terms of construction cost and applicability around existing underground structures (Koga et al., 1986). However, there are experimental results implying that solidified columns have reduced the shear deformation of unimproved soil and mitigated its liquefaction (Yasuda et al., 2003; Tanaka et al., 2003). Yamamoto et al. (2006) conducted dynamic analyses of ground improved with lattice- and column-type solidification. Their results showed that column-type solidification with an improvement ratio of more than 35% reduces excess pore water pressure generated by earthquakes. Furthermore, the new column arrangement shown in Figure 1(a) has been proposed to mitigate lateral flow induced by liquefaction. It was developed and has been verified using dynamic model testing in a 1 g field (Takahashi et al., 2010a; 2010b; 2013; Towhata et al., 2010). The stabilized columns in this configuration interrupt lateral flow in any direction, unlike those placed in square and triangular arrangements."

Jan 1, 2014

By Tristan H. Jones

Rib-related accidents in underground coal mines continue to cause injuries and take lives at a rate of 1.3 fatalities per year for the last 17 years. Prevention of these accidents cannot simply be a matter of installing more rib support, though the eventual final solution will undoubtedly include that component. Ultimately, rib safety will be brought about through an understanding of the causes and mechanisms that cause rib fatalities, and by fine-tuning mining methods and procedures that are currently in place. This paper investigates the factors likely to be most influential in the occurrence of rib fatalities. A careful analysis has been conducted of the rib fatality reports documented by the Mine Safety and Health Administration between 1996 and 2013. The primary outcome is the determination of the relative impact of each type of rib fatality factor and a better understanding of the impact each factor has. Among the rib fatality factors considered, the influence of rib profileis considered for the first time. Mining height, rib stratigraphy, mining cycle, and the standing position of a miner next to a pillar are also considered. Questions are also raised about the current interpretation of rib fatalities due to mining depth, with the indication being that mines operating at the greatest depths may actually have the most respectable rib fatality record among all mining depths. Additionally, a new method of considering rib exposure is developed. Based on the results, recommendations are made for future work. By gaining a better understanding of how particular factors contribute to rib fatalities as opposed to rib failure or stability, it is hoped that future efforts can be more precisely directed towards the desired outcome of fatality reduction.

Jan 1, 2014

By Tracy Shimmield, Philip Samar

"Metals have been mined as ores since pre-history but metal production has increased dramatically in modern times driven by expanding Global GDP. Metal ore mining produces large amounts of waste rock and mine tailings. Mine tailings are the wastes produced after extracting the desired metal from the ore. There are several ways of dealing with this waste, and Ritcey (2005) identifies the following possibilities, land-based storage, backfill to the mine, deep lake disposal and marine disposal. In Papua New Guinea (PNG), both Misima and Lihir Mines adopted the marine disposal option, releasing tailings through a submerged pipe onto the sea floor. This special case is referred to as Deep Sea Tailings Placement (DSTP) in which the tailings deposition is sufficiently deep as to be below the euphotic zone. The most important aspect of deep sea tailings placement is that the tailings are deposited at great depth where exchanges between the seabed and the surface layers are small. The first quantitative multidisciplinary study of tailings impact on the deep sea was carried out from 2006 to 2010 in Papua New Guinea. The physical, chemical and biological work carried out has placed PNG at the forefront of research into the assessment and management of deep-sea environmental impacts related to mining in PNG. The study has provided data which has led to a better understanding of the ecological and geochemical processes in deep water that accompany DSTP in PNG and provided baseline data on deep-sea ecosystems in a scientifically poorly known tropical ocean. Additionally, guidelines on best practice for DSTP have been developed Here we present geochemical data obtained from sediment samples from the marine environment surrounding Lihir and Misima Islands."

Jan 1, 2014

By Pentti Niskanen

"The ventilation system of the Pyhasalmi Mine is described. The mine is located in an area where the annual atmospheric temperature may vary from +30°C to -30°C. Natural ventilation causes serious difficulties because the underground mine is connected by drifts and finger raises to the bottom of the 120 m-deep open pit.The natural ventilation tends to make the ventilation net unstable. The paper describes how the instability characteristics of the ventilation net can be studied and how they have been taken into account when automating the control of the ventilation. In addition, the software, hardware and costs of the system are described. The system consists of 12 automated ventilation doors, two mine fans, 8 elements for sensing the air flow and temperatures, a control panel and a process computer."

Jan 1, 2014

By H. P. Kritzinger, T. C. Kingsley

Rotary kilns are used for a variety of mineral processing operations. Hatch makes use of a kiln model developed from first principles to evaluate designs for its clients. This tool has been applied to a variety of pyrometallurgical applications. This paper illustrates the application of numerical optimization techniques in combination with the kiln model in the interrogation of a generic iron-ore reduction process. The fundamental modelling concepts are explained, followed by a description of the optimization approach. The results show how the combination of the two methods, with modern computing power, can generate a large number of viable design and operating candidates.

Jan 1, 2014

By T. J. Chen

Stone coal containing vanadium is an important vanadium resource in China. Roasting and oxidation of vanadium is the foundation for extracting vanadium from stone coal. This article takes stone coal vanadium ore in Tongshan of Hubei Province as research target to conduct oxidation roasting test on it by using a self-developed low-sodium compound additive and a new optimized technology. Firstly, use potentiometric titration, X diffraction, energy spectrum and electron probe to study valence change, occurrence and phase transition of vanadium during oxidation roasting process. On this basis, primary work is done on oxidation kinetics of vanadium by exploring the steps that control reaction rate during vanadium oxidation process and determining the related dynamic parameter ? apparent activation energy. The study shows that occurrence of vanadium in stone coal of Tongshan is mainly in illite, and that the result of phase transition in roasting process is disappearance of illite containing vanadium, formation of soluble vanadate and potassium feldspar, albite. It further demonstrates that oxidation process of vanadium is step by step (V(?)? V(?)? V(?)), and its oxidation reaction is controlled by diffusion kinetics whose dynamic apparent activation energy is E1=81.19kJ.mol-1.

Jan 1, 2014

By M. D. Budeba

Determining the efficiency of a surface coal mine operation is an essential activity, which can help in deciding on the optimal use of input resources, including effective capital allocation, in generating a desired quantity of coal of a specific quality. Mines operate today in challenging conditions, with diminishing reserves of high-quality coal, remote location of new coal deposits, infrastructure problems, environmental legislation, and the effects of climate. All these have an impact on the performance of a mine. Given such challenges, a company has to be technically efficient compared to other existing coal producers in order to generate profits. It can use the measurement of its efficiency to evaluate its productivity, benchmarking this against the best-performing mines and determining optimal variables in order to minimize slack and achieve the desired outputs. This paper discusses the use of Data Envelopment Analysis (DEA) in evaluating the efficiency of a surface coal mine supply chain for the coal export market. The supply chain is considered to be composed of subprocesses that are modelled as a multistage system. Numeric examples will be used to illustrate the application of DEA.

Jan 1, 2014

By Zhao wen Wang, Ramana G. Reddy, Min Li

"The electroreduction of Co(II) in l-butyl-3-methylimidazolium tetrafluoroborate (BMlMBF4) ionic liquid was investigated by cyclic volatrnmetry at 353 K. The results show that the reaction of Co(II) to Co is irreversible in one step with two electrons transferred. The diffusion coefficient of Co(II) was estimated to be 7.6 x 10-8 cm2 s·1 at 353 K. Then the electrodeposition of cobalt was studied at different cathodic potentials (-0.80 to -0.95 V) and different temperatures (333 to 363 K) in BMIMBF 4 containing 0.20 mol L-1 Co(BF4)z. The deposits were characterized using scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). SEM images show that a uniform, dense, and compact deposit was obtained at -0.80 V and 333 K. The deposits were identified as high-purity metallic Co for all experiments by EDS and XRD.IntroductionCobalt is known as a hard magnetic material and cobalt alloys have been shown to have excellent magnetic properties with adequate mechanical durability and corrosion resistance, which are needed for high performance magnetic recording applications [1-4]. The electrodeposition of Co alloy in the aqueous solution is generally difficult because of the narrow electrochemical potential window of water, which leads to the low current efficiency and worse quality of deposits due to the hydrogen embrittlement. Thus, aprotic ionic liquids (ILs) are expected to be the ideal alternative media for electrodeposition of cobalt or its alloy since ILs usually provide a wide working potential windows, negligible vapor pressure, and acceptable conductivity for electrolysis without the occurring of hydrogen evolution [5, 6]."

Jan 1, 2014

There is a strong demand for nickel metal due to quick development of stainless steel and new electrical materials, most of which is extracted from sulfide resources, resulting in a serious depletion of sulfide resources. Therefore, more attentions have been paying to extracting nickel from nickel laterite, which accounts for some 50% of total nickel metal production. In this paper prereducing?magnetic separation?reduction smelting process is developed to manufacture ferronickel rom two types of nickel laterite DN and GN, assaying 1.42% 1.83% Ni and 49.09% 26.08%Fetotal, respectively. Mineralogy of two types of nickel laterite was determined and optimization of process parameters was conducted to manufacture ferronickel. Prereduction?magnetic concentration process is used to upgrade low grade nickel laterite firstly, two kinds of Ni-Fe concentrates being prepared of DN assaying 2.26% Ni and 69.45% Fetotal and GN containing 2.76% Ni and 38.00% Fetotal. Finally, two types of ferronickel were produced by reduction smelting of prereduced concentrates DN and GN, DN and GN ferronickel contains 2.97% Ni and 6.58%Ni, 89.25%Fetotal and 89.95%Fetotal, respectively. The total recoveries of Ni and Fe of the two ferronickel are beyond 90% and 80%, respectively. There is significant difference in grade of magnetic concentrates and ferronickel between DN and GN laterite due to their different mineralogy, the former belongs to limonitic laterite and the latter saponite one. There are some advantages for this process to manufacture ferronickel from nickel laterite, including effectively upgrading low grade nickel laterite by prereducing?magnetic separation technique, higher throughput and lower energy available for reduction smelting section due to some 40% gangue being rejected in pre-upgrading section, and much less metallurgical coke consumption by using non-coking coal as reductant for prereducing?magnetic separation?smelting process.

Jan 1, 2014

By F. Q. Cheng

Despite the successful industrial practice to recovery KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of different collectors and their concentration are considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt sur-face, with finite contact angle values of between 30o and 40o. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collec-tor adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs.

Jan 1, 2014