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By I. A. Podkamennyi, O. E. Kovalchuk, G. P. Dvoychenkova

"Using the methods of electron microscopy and IR spectroscopy, mineral components in the run-of-mine kimberlites and on the surface of diamonds were identified. The mechanism and sequence of mineral formation on the surface of diamond crystals were established. Systematization and classification thereof were undertaken for the first time ever.INTRODUCTION The high content of diamonds sized -5 mm in the kimberlite ores of Western Yakutia determines their processing depth in the size class 0.5 mm and finer [1, 2]. These diamonds are recovered by grease and froth separation based on the natural hydrophobic properties of the crystals. When refractory altered kimberlite ores are fed into the industrial process, the performance of grease and froth separation of the diamond ore greatly deteriorates. [4, 10, 15, 17]. Altered kimberlites are known to contain up to 90% of secondary minerals. This reduces by up to 40% the recovery of diamonds by grease and froth separation. [6].Diamond crystals from the grease and froth separation tailings were investigated. On the surface of the examined diamonds, hydrophilic mineral formations were identified, responsible for reduced recovery by physicochemical separation methods [3, 12, 18]. The aim of this study was to identify and describe the relationship between the composition of kimberlite ores and mineral formations on the surface of diamond crystals in order to systematize, classify, and then develop methods of removal in grease and froth separation processes. MATERIALS Following materials were examined in this study: - kimberlites of various material composition, - resulting slimes, - diamond crystals from kimberlite ore processing products."

Jan 1, 2018

By J. Y. Tian

In view of the fact that many domestic iron ore-dressing plant applying flotation cells in the re-verse flotation, to improve the technical level of magnetite reverse flotation, we apply such a technological process of one stage rougher and two stages scavenger flotation column respectively. The middling from the two stage scavenger process are returned to magnetic separation for condensing. By contrast, the technological process of one stage rougher and one stage cleaning flotation cells is made up of by multi-magnetic separation and magnetic middling regrinding separations. It has been proved that the flotation column we offer can simplify the technological process structure, obtain advanced technical indexes, run the system smoothly, reduce energy consumption, and be environ-mental friendly.

Jan 1, 2014

By C. L. Tang

Parts of the wastewater are reused directly and the rest moderately purified and reused, so the utilization rate of wastewater of the whole processing plant reaches 100 percent. At the same time, beneficiation indicators have been improved stably, and great economic and social benefits have been achieved.

Jan 1, 2014

By Stephen Simukanga, Jewette Masinja

"Mining has been going on commercially in Zambia for over 100 years. The backbone of the mining industry has been copper production and its by-products of cobalt and gold. Over these years, the mining industry ownership structure has swung from private ownership to state ownership in 1972, and back to private ownership in 1995. Environmental management was first introduced into the body of Zambian legislation in 1991 through the promulgation of the Environmental Protection and Pollution Control Act (EPPCA). The Act’s main functions included the protection of the environment and control of pollution, and in particular to provide for the health and welfare of the people, animals, plants and the environment in general. This Act, was replaced in 2011 by the Environmental Management Act (EMA). The new Act has a number of new elements including: mainstreaming environment in national planning, it provides for the domestication of multilateral environmental agreements, enhances public participation issue, creates a central environmental information depositary, elaborates access to information principles, establishes an environment fund, creates enforcement orders, provides for both Zambia Environmental Management Authority and members of the public to sue for damages following environmental pollution, and provides for the appointment of honorary Inspectors. In addition to this, the Mines and Minerals Act of 1995 provided, for the first time, a section on environmental management in the mining sector. This section also created the Environmental Protection Fund (for mining), and made it obligatory to undertake environmental impact assessment before mining permits could be issued. The Environmental Protection Fund has now been established, as provided for by the law, and currently has more than USD9.0 million in the account. Secondly, environmental auditing is now being carried out annually on mines around the country, the effect of this has been a significant improvement in the environmental management of mining in Zambia. This paper looks at the response of the Zambian mining sector to these pieces of environmental management legislation, and the direction that the mining sector is expected to take on environmental management going forward."

Jan 1, 2014

By Grigory Voyloshnikov, Sergey Petrov, Vladimir Petrov

"The treatment of high-grade copper gold-bearing ores is practiced extensively. However, due to low concentration of copper the application of a separate process for copper recovery can make this process uneconomical. The copper, in particular: in oxide minerals, intensively bounds with cyanide during conventional cyanidation. In this case, cyanide is not able to react with precious metals and the consumption of cyanide increases. The resulting copper cyanide complexes have a negative effect on the recovery of gold. Due to decreasing of the process parameters, a repeated use of the recycled solutions can be hindered, especially in the case of heap leaching. The technology of copper removal from the process solutions with simultaneous regeneration of free cyanide from copper-cyanide complex and producing of a saleable high-grade copper concentrate was developed. An important feature of this technology is simplicity, the absence of complex or dangerous operations and the use of common reagents. The choice of equipment depends on the ore treatment option: heap or vat leaching. Also, simpler equipment schemes are available. The studies, tests and industrial practice show that if the concentration of copper can be decreased down to the first numbers of mg per ppm or lower, it is reasonable to maintain the process copper grade in the recycled solutions at 30-50 mg/L. In this case, recycling of cyanide-bearing solutions is unlimited. The regeneration of free cyanide from that of bound with copper and other cyanide complexes is 95-98%. The grade of copper in the concentrate is 55-60%. This technology is an economically competitive option, in particular: with the account of the sales of copper concentrate. The removal of copper has a positive effect on gold recovery, especially during heap leaching. In addition to, this offers significant benefits in reduced costs."

Jan 1, 2014

By Herman D. Mendoza

A rapid recovery/recycling process was introduced utilizing the surface-chemical properties of finely dispersed mercury and alumina (Al2O3) fibers in aqueous environment. The conventional method of amalgamation or .ball milling. involves the mixing of a substantial amount of mercury to collect free gold during the grinding stage. In effect, a portion of the mercury is transformed into minute droplets that readily float and disperse in the amalgamation effluent. The fine droplets of mercury in the dispersion readily attached onto the positively charged macroscopic alumina fibers (i.e. = pH 9.8) at conditions pH 3 to 10. When an effluent from settling procedure after an amalgamation-grinding stage is passed through a column-bed packed with alumina fibers, maximum collection of negatively charged finely dispersed mercury occurred at pH 3 to 6. The collection/attachment efficiency was 99.5%. The collected droplets of mercury, which are left in the column-bed of alumina fibers, were subsequently rinsed with alkaline solution at pH 10 to 11.5. At these conditions, both mercury and alumina fibers carry negative surface potentials and resulted in the partial detachment of mercury from the alumina fibers. The detachment efficiency was only 30-35%. The attachment/detachment mechanisms in this study were analyzed using the DLVO theory.

Jan 1, 2003

By S. V. Bogdanov, S. I. Grishaev

"The article presents the materials about the appropriateness of the use of rental indices to assess the effectiveness of the use of deposits of rare earth elements (REE). The authors suggest from the standpoint of rent payments to rate for the owner the possibility of using the anticipated rental income as the indicator for the analysis of preferences and economic significance of enrichment of extracted raw materials in the emerging field of rare earth metals (REE). Usually from ore mined at the fields, for flotation technology to produce concentrates with collective REE, then they are subjected to chemical-metallurgical processing of the received products are divided into pure oxides, chemical compounds or isolated from them pure metals and alloys. This commercial product is shipped to the buyer. REE were a non-renewable natural resources, so the calculations for determining differential and specific rent showed that during the development of the technologies of mineral processing of a specific field it is necessary to consider what the expected rental income depends on the magnitude of differential rent is related to the volume of production of REE for the whole planned period of exploitation of natural resources. This income is determined by the amount of stock field. For long-term exploitation of the deposit is observed in almost direct proportional dependence between the annual differential rent and the rental income. The decrease in rents in the long run is determined by the change in the composition of ores included in the extracted raw materials and the balance between light and heavy REE. The largest 70% reduction of the rent projected for ""cerium"" fields, while for ""yttrium"" these losses are considerably smaller. Tomtor, Chuktukon and Katuginskoye Russian deposits are characterized by a level of rent that is comparable to the mastered foreign sources of REE. Thus, the enrichment of minerals with REM in the domestic deposits is quite competitive at the world level. INTRODUCTION Deposits of rare earth metals (REE) are non-renewable resources that should be developed and used so that it would be possible to provide a reduction due to payment of appropriate resources for future generations. This compensation, due to the reduction of natural resources, can be carried out both in natural and in economic terms (1). When analyzing economic compensation options, particular attention should be paid to rental income in assessing the attractiveness of using different REE deposits. It is known that absolute and differential rents are summands when calculating the value of natural rents. The value of the absolute natural rent is proportional to the unit price of the product obtained from mineral raw materials and sold on the commodity market. Limitations, as well as the use in production processes and business, contribute to the gradual reduction of natural resources, which increases their consumer value and affects the price of commodity products from primary raw materials."

Jan 1, 2018

By Artem Dolotov, Alexander Ter-Oranesyants, Saveliy Kaplan, Boris Axenov, Vasiliy Kovalev, Valeriy Tsyplakov, Konstantin Grigorjev, Nikolai Vorob’ev-Desyatovskii

The issues of double refractory gold ores pressure oxidation were considered. It was demonstrated that along with chloride autoclave preg-robbing which has been studied there are other negative external and intra-autoclave processes resulting in gold losses. It was found that an ingress of even low concentrations of NaCN, ferrum(II) and ferrum(III) cyanide complexes, as well as thiocyanate compounds into the autoclave leads to decrease of gold recovery during further cyanidation in a "carbon in leach" process (CIL). Admixtures depressing recovery of gold can get into the autoclave together with water in the result of industrial accidents or due to peculiarities of recirculation of industrial water used for feed pulp preparation or with quench-water used for process temperature maintenance. In contrast to a chloride preg-robbing which occurs only at pressure oxidation of double refractory gold ores, cyanide preg-robbing starts in the autoclave feeding tank (so-called «upper» preg-robbing). Possible causes of cyanide autoclave preg-robbing and requirements to the quality of water supplied to autoclaving were discussed.

Jan 1, 2014

By E. Guerrini, M. Maccagni, J. Nielsen

"Lead is the most important material able to meet the current demand for energy storage. The lead acid battery is reliable, efficient and inexpensive. Continuous developments in battery construction are providing improvements in all aspects of the batteries’ performance. The lead acid battery is both the main lead product and the main raw material for lead production. More than half of the lead produced is from secondary smelters where batteries are the most important feed material. The environmental pressure on lead production has been increasing for many years, and continues to become stronger and stronger. The lead production processes and technologies themselves will require updating to meet the new regulations. Although they are very strict now, they will become even more so and current technologies may not be sufficient. Because recyclability is a strong point for the lead acid battery, the secondary smelters need to reduce the environmental impact as much as possible. In recent years, the secondary smelters underwent impressive changes in this direction, but some more improvements are possible. Electrochemistry can offer a step change improvement in making secondary lead production more environmentally friendly. Engitec has developed an electrochemical process base on a very high current density (high productivity) cell using an inexpensive electrolyte and at a relatively low cost. In this paper, the latest update on the technology is provided. INTRODUCTION The lead acid battery is considered the “walking dead” by some new technologies trying to replace it. It has played and will continue to play a very important role in our lives because it is inexpensive, fully recyclable and the existing lead and the mine reserves guaranty enough material for the extended future. According to the life cycle, the lead acid battery is the cheapest and the most effective system to store energy. Lead is practically a close loop where lead battery production consumes more than 80 % of the produced lead but contemporarily it is the most important raw material for the production of metallic lead. In fact, nowadays, the secondary production has overcome primary production and this trend is expected to continue. Primary lead is the make-up material for the existing battery production and the source of lead for the construction of the new ones."

Jan 1, 2018

By V. Panayotov

Slag and by-products of metallurgy bear valuable components and their processing raises an in-creasing interest. Coke and iron have to be separated and other components have to be depressed, in order to obtain sellable high quality copper concentrates. Use of classical mineral processing technologies, such as magnetic separation, sulphidization, hydrometallurgy, etc. yields copper concentrates with grade of 4%~6% Cu. Copper is lost in tailings and the whole technological cycle is low profitable. Technology proposed applies an electrochemical treatment of the industrial water entering the flotation cycle. Iron and iron compounds that do not bear Cu, coke and gangue materials are depressed during the copper flotation. Copper concentrate of grade of 9.8%~10% Cu is obtained at simultaneous increase of Ag recovery by 8%~10%. As a result company profitableness is increased. Technology proposed is easy to implement, it does not require changes in the existing technology flow-sheet, and additional investment is low. The flotation process can be aided by a specially developed system for real-time analysis of the obtained copper concentrate which allows in-time corrections in the flotation parameters and entire process control. Applied flotation schemes, technological parameters and results obtained are described.

Jan 1, 2014

By Kunihiko Yamaguchi, Gjergj Dodbiba, Toyohisa Fujita

Usually magnetic separation is performed to separate ferromagnetic, paramagnetic and diamagnetic particles by controlling magnetic field strength. In this research the wet high gradient magnetic separation at various kinds of magnetization of medium has been investigated to separate different kinds of magnetization of paramagnetic mineral particles from each other. Most of week paramagnetic particles are captured at high magnetic field using superconducting magnet. If the magnetization of fluid is larger than that of paramagnetic particle, the paramagnetic particle cannot be captured in the direction of magnetic field. The paramagnetic particles of different magnetization such as hematite, chromium oxide, perovskite and rutile are separated in different magnetization of fluids. These particles are present in the incinerated bottom ash. The separation is useful to recover titanium oxide from bottom ash and the removal of chromium of bottom ash is important to reuse the bottom ash as cement. The used fluids are paramagnetic liquids dissolving paramagnetic salts and the water based magnetic fluid dispersing the stable ultrafine magnetite. The dispersion condition of particles related to zeta-potential of the suspension feed is also important to separate effectively by controlling pH

Jan 1, 2014

By Xingshi Yang, Ghislain Bournival, Seher Ata

"Particle-laden interfaces are a fundamental research topic in froth flotation since the process involves particle-coated bubbles in both the pulp and the froth phase. In most experimental studies the characteristics of the particle layer in multi-bubble systems are poorly defined. An experimental setup has been developed based on a Langmuir-Blodgett (L-B) trough. The modified trough allowed introducing an air bubble beneath the particle monolayer formed at the air-water interface which made the study of the interaction between the bubble and the monolayer under various pH values possible. The monolayer characteristics of the particles were also studied and compared in terms of surface pressure (?-A) isotherms and packing factor. On compression, the particles formed branched structure at high pH whereas a uniform monolayer was formed at lower pH. Observations related to the behavior of particles during compression and expansion cycles, and the coalescence of a bare bubble with the flat particle laden interface were provided and the implication of the results for flotation process was discussed.INTRODUCTIONFroth flotation is known for its versatility and ability to concentrate low-grade, complex ores. It is considered a physico-chemical process in which particles attach to air bubbles, depending on their hydrophobicity as well as other factors, and are carried to the surface to form a froth layer. Reagents are used to stabilize bubbles and the froth layer (Pugh, 1996). However, particles, which are carried by the bubbles or entrained, significantly contribute to the stability of the froth phase (Ata et al., 2003; Zanin et al., 2009; Bournival et al., 2015a). Their relevance in mineral processing has led to a number of fundamental studies on the effect of particles and their properties on the process of froth flotation.Flotation systems are particularly difficult to characterize due to the broad range of properties of particles (e.g. size, liberation, hydrophobicity, etc.) and inconsistent operational conditions (e.g. changes in water quality, reagent addition, etc.). Several studies have made the use of well characterized particles in laboratory conditions. Such studies allowed the finding of an optimal contact angle for the stabilization of the froth phase (Johansson and Pugh, 1992; Ata et al., 2002). Froths have a large number of bubbles so that individual interactions are not observed. The study of two bubbles allows to determine the stability of the bubbles, with particles, and to some extend the stability of the bubble-particle aggregate (Gourram-Badri et al., 1997; Bournival et al., 2015b). The removing of particles between two bubbles may also be studied from a Scheludko cell (Johansson and Pugh, 1992) or by observing a bubble with a flat interface (Sethumadhavan et al., 2002). However, these systems provide limited information on the arrangement of the particles."

Jan 1, 2018

By L. Weitkämper

The big challenge at present and in the future is the economization of resources. This is applied for the whole industry but particularly in fields of mineral processing. The most important resources are energy and water. The shortage and price advance of energy is worldwide noticeable whereas the shortage of water is regionally limited at present. However due to the increasing world population, associated with a rising standard of living, water will become more and more important. Studies of the Unesco from 2001 indicate that the total water consumption raised seven times since the last 100 years at a growth of population of just three times. (UNESCO-Currier, 10/2001). This trend is going to be increased. While today more than 90 % of the humanity has access to clean water, in 2050 just about 50 % will be in the same situation. These figures indicate the importance of a gentle handling with the resource water. Further more the disposal of fine products, containing most of the water, is an environmental concern and in the future the mining and processing of raw materials will become important and necessary in desert, arid or permafrost areas. In these areas just efficient dry cleaning technologies will allow an economical beneficiation or better enable the processing at all. Most of the separation technologies with high throughput rates in mineral processing are based on wet processes. This applies especially for the separation of fines. Though there are some dry technologies available for the separation of coarse materials, like pneumatic gravity separation [air jigs and air tables], magnetic separation and not least sensor based sorters. Dry separation of fines is bounded mostly on cost intensive and low throughput technologies. The pneumatic separation undergoes at present a renaissance, mainly due to the development of the all air jig by the German supplier Allmineral. This newly developed sorting device yields good results in the separation of coarse to medium size material. All these facts and figures show the potential and motivation for developing an efficient dry separation device for fines. The following article delineates the development, performance and chance of a new dry separation technology for fines.

Jan 1, 2014

By J. Zou

With the increasing applications of the Chinese metal magnetic liners, the requirement for their technical specifications has become stricter and stricter. It is necessary to deeply analyse the metal magnetic liners in order to improve their reliability and economics. The key issue of metal magnetic liners is magnetic forces: their attractions to mill shell and protection layer. Mathematical models were developed using finite-element analysis software and systematic simulation analyses of the two most critical indexes of magnetic liners were performed to find out the most important parameters and their effect on the liner?s characteristics. The relationships between magnetic forces and installation gaps, thickness of permanent magnets and thickness of protection layer may be used to guide the design of metal magnetic liners for ball mills in order to achieve good economic indexes.

Jan 1, 2014

By Xiaodong Jia, Williams. Richard A.

This paper describes the recent developments, arising from research at Leeds, in the computer modelling of packing of complex shaped particles and prediction of physical properties of the structures represented by the packing. The computer model DigiPac, is capable of packing particles of any shapes and sizes in a container of arbitrary geometry. The ability to predict packing structure of real particle shapes and to compute directly some structure-dependent physical properties (such as liquid permeability, mechanical strength/ stability, compaction and sintering, dissolution and leaching, etc.) is obviously highly desirable and has significant potential in industrial applications. Examples are presented relating to the packing of granular materials.

Jan 1, 2003

By C. Abbruzzese, F. Vegliò, S. Ubaldini, R. Massidda

"Gold solubilised during cyanidation can be recovered by precipitation (Merrill-Crow process) or by adsorption onto activated carbon, these being the techniques applied in industrial plants.Precious metals (Au, Ag) adsorbed onto activated carbon are extracted during a subsequent stage in aqueous phase, by various technologies, such as hot elution (70-80°C) or under pression desorption (100-130°), with hydro-alcoholic solutions.This stage is of great interest from an economic point of view, due to the high energy costs. Temperature represents the critical kinetic factor.The aim of this paper was to study the influence of different water/organic solvent mixtures (isopropyl alcohol, ethanol and ethylene glycol) on the desorption process.The experimental work was carried out on laboratory scale, using activated coconut carbon with different temperatures and extraction times, without adding cyanide.Best results have been obtained in this order: isopropyl alcohol > ethylene glycol > ethanol. Starting from gold concentration of about 5 g Au per kg of carbon, best kinetics resulted in 97-100% of gold extraction, after 8 hours of desorption, at a temperature of 80ºC."

Jan 1, 2003

At times the phosphate industry, in Florida, encounters phosphate rock that gives lower than expected P2O5 recovery in the rougher plant section. The drop in recovery is typically 10% and as much as 30% or more. Variations in feed quality from day to day, shift to shift and even from drag-line to drag line, represent a challenge to the beneficiation plant operators and reagents? suppliers. Therefore, this characterization study has been initiated to identify the reasons for the differences in flotation behavior of such feeds. The study involves many samples to cover such variations. The characterization work includes: ? Mineralogical and chemical analysis; ? Size, shape, surface roughness and porosity analysis; ? Surface charge and surface contamination with other phases (minerals); ? Clay content and its relationship to phosphate and silica particles. The results correlated with flotation data and adsorption density measurements clearly establish the statistically significant variability in characteristic features that influence flotation response. This article discusses results from the above listed studies. On the basis of the obtained data, recommendations of practical approaches to overcome the problem of feed variability in phosphate flotation plants are delineated.

Jan 1, 2014

By A. J. Ren

The ore, dealt with in this paper, is a certain rutile in Shanxi province, China. A trunk flowsheet with gravity concentration is used, and the TiO2 grade of rutile concentrate is about 90%, but the TiO2 recovery is less than 50%. In order to increase the rutile recovery, the laboratory test, using the truck flowsheet with flotation, is carried out. The flowsheet is that firstly floatable gangue is re-moved by flotation; secondly rutile is recovered by flotation; and thirdly impurity is separated by LIMS, HIMS, gravity concentration and flotation from the rutile concentrate. In rutile flotation, BK423, a phosphonic acid, is used as rutile collector, and Na2SiF6 is used as silicates depressant. The experimental result shows that the recovery of rutile concentrate is improved obviously, and the recovery of ultimate rutile concentrate is 68.01% TiO2 and 84.88% rutile. The TiO2 grade of first concentrate is 95.98%, and the TiO2 recovery is 45.60%. The TiO2 grade of second concentrate is 80.53%, and the recovery is 22.41%. Furthermore, magnetite and ilmenite are recovered in the flowsheet.

Jan 1, 2014

By P. T. Nguyen

The analysis of particle capture by an air bubble by two separate phenomena of collision and attachment has been difficult due to the uncertainty in determining when and where the two phenomena begin and terminate at the bubble surface, respectively. Therefore, a unified analysis was developed by solving the motion equation for the particle capture as one process. No distinction be-tween collision and attachment was made. Both the liquid film described by the micro-hydrodynamic resistance functions and the surface forces were included in the new model. The model predictions with the DLVO (Derjaguin-Landau-Verwey-Overbeek) surface forces did not agree with the experimental trajectories of latex and silica spheres. The model predictions with the inclusion of the non-DLVO attractive surface force agreed with the experimental data. The non-DLVO force reduced the repulsion between the non-attaching particle and the bubble, and significantly increased the attraction between the attaching particle and the bubble. The unified analysis is capable of predicting particle capture without the use of the induction time. The unified analysis also shows significant influence of the short-range hydrodynamic interactions on the collision which has been previously ignored.

Jan 1, 2014

By Carlos Gualdron, Elizabeth Gomez, Rafael Bolivar

The productivity index of the Coopracarcegua Ltda., a mid-size coal mining company of Norte de Santander, Colombia, was related absenteeism using accident, productivity and profit data four years. The analysis was based on type, severity and frequency of accidents, number of absentee days; price per metric ton, and other relevant parameters. The enterprise is formed by 5 different mines of thermic coal, each one with different exploitation technologies and different productivity. Each mine was analysed separately and the loss of profit due to absenteeism was calculate for each one. The study showed that the foregone earnings due to absenteeism in terms of the whole productivity of the enterprise was about of 6.6% of the total profit average the 4 years, with calculated values of 14.7%, 3.5%, 8.4% and 4% per year in the evaluated period. The study identified that the most important cause of absenteeism was "General Disease". The foregone earnings in 2009, the highest loss for the analysed period, was about US$ 0.937 million and during the whole evaluated period was US$ 2.46 million.

Jan 1, 2014