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

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

Jan 1, 2003

By M. Prasad

Growing concern over increased levels of atmospheric carbon dioxide has prompted new interests in development of materials and techniques for its sequestration. Various research and developmental work on different aspects of carbon capture technology are being extensively carried out worldwide. The main objective of the present work is to synthesize a HAS material having high capacity and robust ability for recycling to capture greenhouse gases with special reference to carbon dioxide (CO2) from the sources from where it is released to the atmosphere. Existing CO2 capture techniques involves the use of solid materials that lack sufficient stability for repeated use or liquid adsorbents that are expensive and require significant amounts of energy. Keywords: greenhouse gases, carbon capture, solid adsorbent, HAS material

Sep 1, 2012

By A. V. Nguye, P. A. Harvey

Previous studies have reported that inorganic electrolytes can enhance floatability of coal. The research has shown that the enhancement, if any, is highly dependent on changes in solution pH, type of electrolyte, and electrolyte concentration. The reasons for this are still not clear. In this study the floatability of coal particles in mono and divalent salt solutions was investigated. The zeta potential and hydrophobicity of the coal was measured experimentally, and a modified Hallimond tube was used to determine the floatability of coal particles by single bubbles, where the collision efficiency was equal to unity. The experimental information was used in conjunction with the Hogg-Healy-Fuerstenau equation to quantify the electrical double layer interaction. It was found that for low electrolyte concentration (less than 0.1 M) solutions the flotation recovery of coal particles was less than that for distilled water, and decreased with increase in concentration. Conversely, at electrolyte concentrations above 0.1 M, flotation recovery increased with increasing concentration. Both of these results are consistent with previous observations, but are inconsistent with expectations when considering the possible influence of electrical double layer interaction. A possible mechanism, based on the existence of the pre-existing submicron-sized gas bubbles, known as bubstons (i.e. bubbles stabilized by ions), present in water in close proximity to the hydrophobic coal surfaces is discussed in line with the early observation of flotation improvements by microbubbles “nucleating” on hydrophobic surfaces. In particular, the dependence of the bubble-particle attachment efficiency on electrolyte concentrations supports hypothesis on the salt-dependent and ion-specific existence of bubstons. However, a theoretical explanation of the transition salt concentration (at about 0.1M) is deficient at present. The existence of these submicrobubbles in close proximity to hydrophobic surfaces is not trivial. They can (as can individual gas molecules or other solutes) mediate and extend the range and magnitude of the attraction between hydrophobic macroscopic surfaces. These bubbstons may explain the curious phenomena of the socalled long-ranged hydrophobic attraction measured with the Surface Force Apparatus and Atomic Force Microscopy, and the slippage at hydrophobic surfaces. Finally, the coalescence of bubbstons affects the rupture of liquid films at a very large thickness (over 100 nm), observed, but unexpected, by flotation chemists.

Jan 1, 2003

By Yimin Zhu

This paper introduces the sixteen mappings and rules of mineral flotation and the subgroup, period etc in periodic table of chemical element to provide mineral flotation workers to refer in theory and practice research. the nine mappings and rules of mineral flotation and the subgroup, period are Saline minerals including the first main groups and collectors of aliphatic acid and aliphatic amines, Minerals including the second main group elements and collector of aliphatic acid, Hydrated ion of the second main group elements and quartz flotation, The floatability of oxidized minerals including the four main group elements, Organic acid including the fifth main group elements and wolframe, tin flotation collectors, The floatability of sulfide minerals including the fifth main group elements, Inorganic compounds including the seventh main group elements and mineral flotation regulator, Oxidized minerals including the forth Subgroup elements and organic flotation agents with phosphorus and arsenic, Oxidized minerals including the fifth subgroup elements and organic floating agents including the fifth main group elements, Minerals including the first subgroup elements and CN-, Sulfide minerals including the second subgroup elements and CN-, The effect of the highest N-valency inorganic acids or salts including p area elements of the third period in mineral flotation, Oxidized minerals including transition elements of the forth period and 3# flocculating agent, The floatability of minerals including elements of the sixth period, Element area of generating compositions and the collecting theory of mineral flotation and so and. Keywords: mineral flotation, periodic table of chemical element, subgroup, period, regulator, coordination chemistry

Sep 1, 2012

By Bent Babel, Martin Rudolph

"The characterization of reagent-mineral interactions in flotation systems of finely intergrown ores holds difficult challenges for the applicability of standard techniques like Hallimond tube tests and contact angle experiments or renders them impossible due to a lack of sufficient samples in terms of quality and quantity. This disadvantage may not apply to more sophisticated techniques, but these often do not work in an aqueous environment. We present the utilization of an atomic force microscope with a hydrophobic colloidal probe to characterize the wettabilities of individual mineral domains of an ore sample, while additional spectral information is gathered by Raman spectroscopy. The exemplary ore sample investigated is mainly containing cassiterite and quartz, therefore the reference measurements like Hallimond tube tests and contact angle experiments were carried out with this binary system as a comparison. The focus of the study lies in the correlation of data gathered by the atomic force microscope and the Raman spectrometer with data from standard techniques. Finally, the applicability of the colloidal probe atomic force microcopy technique for reagent-mineral investigations is critically evaluated.INTRODUCTIONThe focus of this paper is the application of colloidal probe atomic force microscopy (CP-AFM) for theinvestigation of reagent-mineral interactions on a binary system of cassiterite and quartz. This and similar concepts using hydrophobic AFM probes have been applied by multiple authors (Rudolph and Peuker, 2014a; Rudolph and Peuker, 2014b; Wada et al., 2017; Xie et al., 2017). The hydrophobic interaction is the main interacting mechanism for the hydrophobic colloidal probe with hydrophobic sample surfaces and the long range attractive component has been accounted to nanobubbles on the interacting surfaces (Yakubov et al., 2000). More detailed information on nanobubbles are available in two reviews compiled by Attard and Hampton (Attard, 2003; Hampton and Nguyen, 2010). This paper is based on the work by Rudolph and Peuker comparing different AFM based measuring concepts, additionally gathering data with Raman spectroscopy and correlating results of microflotation and CPAFM measurements (Rudolph and Peuker, 2014a; Rudolph and Peuker, 2014b)."

Jan 1, 2018

By W. Kobal

The extraction of nickel (Ni) and cobalt (Co) from the laterite deposit of Ramu nickel-cobalt Project in Papua New Guinea was performed in this study. Chemical analysis by Inductively Coupled Plasma (ICP-AES) atomic emission spectrometer, SPS-3000 (Seiko Instruments (Inc.), shows the ore contains 48% Fe, 1% Ni, 0.1% Co, 1.8% Al, 0.14% Mg, and 0.8% Mn. Characterization by X-ray diffraction (XRD) analysis of the laterite ore obtained from the mine site shows the ore contains 70 to 80% goethite (FeOOH), assuming Fe content of 48% is mainly from geothite. The main leaching parameters investigated include; slurry temperature, leaching time and sulphuric acid (H2SO4) concentration to evaluate nickel and cobalt extraction. For all experiments, 10g batch samples are put into 300 ml beaker containing 100 ml of sulphuric acid of varying concentrations (1M, 2M, 4M). During the leaching period, 5 ml slurry samples are withdrawn at different times and filtered to obtain filtrate for ICP analysis to monitor nickel and cobalt extraction. Solid samples at the end of all tests are also obtained by filtration and after drying, XRD and ICP tests are performed to monitor nickel and cobalt contents. According to the test results performed at normal atmospheric pressure, over 99% of nickel and over 50% cobalt were extracted into solution within 120 min at 95ºC in 2M H2SO4 solution. Similar results were obtained when only temperature was reduced to 90ºC, but cobalt extraction increased to over 70% when leaching time was increased to 240 min. Further reduction in temperature to 80 and 60ºC resulted in reduction of nickel and cobalt extraction. At the end of each leaching test, magnetite was seen to attach to magnetic stirrer. The study showed nickel can be completely leached into solution but cobalt only up to 70%. Keywords: atmospheric pressure, sulphuric acid leaching, nickel laterite

Sep 1, 2012

By W. H. Cheung

Nickel and cobalt production relies heavily on the processing of nickel laterite ores; these ores contain the majority of known Ni and Co reserves, 80% and 90% ~ 95%, respectively. The Caron process is used to extract Ni and Co metals from low-grade nickel laterite ores (1% Ni and 0.1% Co). It involves selective reduction of NiO and CoO minerals followed by ammoniacal leaching. Despite low metal recoveries, this process continues to be technically and economically reliable and thus commercially important globally. However, keeping the Caron process cost-effective has been a challenge for industries because of increasing economic and environmental pressures. Although studies of the Caron process have been extensive, significant improvements in recoveries of industrial processes have not been forthcoming. Reported industrial metal recovery from high iron content ore is only 80% ~ 85% for Ni and only 40% ~ 45% for Co; recovery is even lower for ores rich in magnesium. The real difficulty here is that there is no complete understanding of and control over the complex series of reactions in the ore and in the leaching solution during processing. Achieving effective metal recoveries from the Caron will require control of the mineral transformations, which affect the activation of minerals by reduction. In this study, the effect of over-reduction was investigated, which superseded the effect of activation by lowering the activity of the minerals and thus metal dissolution. Reduction was carried out in a batch reduction apparatus with 1:1 and 1:2.5 CO/CO2 gas mixtures from temperatures of 500 ~ 700°C and residence times up to 60 minutes. The pre-reduced ores were leached using a standard ammoniacal leaching test. Thermodynamic analysis and possible effects of stable phase field on leaching was examined. The results suggest that control of over reduction effects are directly related to the mineral transformation and reduction conditions.

Jan 1, 2014

By Rob Morrison, Andrew Scott

"Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data - especially with semi-automated data acquisition by instrumented mine equipment.However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model.An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc, not only have many areas of interest but also have very different conceptual models by which they evaluate performance.It is too ambitious to attempt to bring all of these cultures together - in a single step.However, the success of the Mine to Mill - project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from ore body model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling.However, in both cases the data collected is strongly focused on the technical requirements - not on the business model.This paper considers how to define at least some of the key decision points in terms of some case studies.Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning."

Jan 1, 2003

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition.The article is devoted to the promotion of the concept of mineral processing in modern realitiesof the deficit of high-quality ores and increase their demand.Normative and methodical documentationsfor specific types of analysis with the definition of the field of application are shown. For example,the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore fieldare tested. The development of mineralogical methods, and testing of specific raw materials are shown.The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field. KEYWORDS Technological mineralogy, rebellious ores, ore quality assessment, ?mineralogical-analytical methods INTRODUCTION A highly intense production of many types of mineral raw results in gradual depletion and deterioration of mining-geological and mining-technical conditions of development. Relatively easily accessible and rich deposits are getting exhausted in the first place, and it is necessary to involve poor and rebellious ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral raw, creation of scientific and methodological prerequisites for solving the problem of rational development of mineral raw, maximal extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and raw base. The article is aimed at updating tasks that should be addressed within the applied mineralogical researches: – the forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of raw, – interactive monitoring of these indicators by mineralogical and analytical methods; – assessment of environmental consequences of mining and processing of minerals and measures that eliminate these consequences."

Jan 1, 2018

By Xiaoming Wang

This paper describes a new magnetic separator integrating dynamic permanent magnetic force, gravity and flow dynamics to enhance the quality of the iron concentration. This equipment can increase the grade of concentrate by controlling the formation of magnetic agglomerations to reject most gangue. Test results indicates that the compound force field separator can be applied in improving the quality of iron concentrate and has a wide range of potential market applications. Keywords: magnetic separator, compound force field, rotating magnetic system, magnetite concentration

Sep 1, 2012

By Aziza A. Yousef, Suzan S. Ibrahim, Mahmoud A. Arafa, Mohamed A. Abdel Khalek

In view of the shortage of soft water all over the Middle East countries, seawater may be used to replace the fresh water in flotation beneficiation. The flotation process required about 7 m3 of fresh water/ ton ore. This article aimed to study the effect of seawater cations and anions on the flotation process of four important mineral commodities. The adsorption of collector, zeta-potential, zero point of charge and floatability of pure minerals were studied. The individual effects of different cations and anions that are predominant in seawater, within their more or less actual concentrations were studied on individual mineral and on groups of them. The troublesome Ca2+ and Mg2+ ions, in the anionic circuit could be controlled by soda ash addition to the pulp before the anionic collector. The addition of sodium silicate improved the floatation selectivity of mineral mixtures and natural ore. At the optimum conditions the calcareous phosphate ore yielded a concentrate recovery of 83% with a grade of 34% P2O5, with 0.61%MgO, which from an ore assaying (25.3% P2O5 and 9.4% MgO).

Jan 1, 2003

By Chuansheng Luo

If lead-zinc ores have high oxidation rate, separation of lead and zinc is very difficult. This paper studied the technology of preferential flotation by the coarse grinding and re-grinding. The lead concentrate grade is 51.40% and the lead recovery is 62.83% when feed grades Pb 1.74% and Zn 6.46% with oxidation rate being 13.75%. At same time, the zinc concentrate grade is 50.07% and its recovery is 90.01%.

Sep 1, 2012

By Guanghua Ai, Xiong Huang, Huashan Yan, Ting Li, Tingsheng Qiu

"Cyanide tailings of gold and silver concentrates contain considerable quantities of copper-lead-zinc sulfide minerals that can be recovered. However, the strong inhibition effect of cyanide often makes it difficult to recover these sulfide minerals effectively. In this research, a sample of cyanide tailings was investigated based on the principles of process mineralogy; activating flotation tests were carried out for the target minerals in the tailings, and the activation mechanism of the activator and its influence on the target minerals were investigated by Fourier transform infrared spectroscopy (FTIR). Mixed flotation of copper and zinc was carried out using QJ-01, a combined agent containing sulfite, as the activator of copper and zinc minerals, and ammonium dibutyl dithiophosphate (ADD) and butyl xanthate (BX) as the combined collector. Copper concentrate was obtained from the mixed concentrate by using a combined inhibitor of sodium sulfide and zinc sulfate to inhibit the zinc mineral. Zinc concentrate was extracted from the copper tailings by using copper sulfate as the activator and BX as the collector. The flotation test yielded copper concentrate with a grade of 22.56% and recovery of 76.96%, and zinc concentrate with a grade of 42.56% and recovery of 82.29%, which shows that comprehensive recovery of the sulfide minerals – copper and zinc –from the cyanide tailings was realized. The FTIR analysis showed that CN- was chemisorbed on the surface of chalcopyrite and sphalerite following cyanide treatment, while the combined activator QJ-01 containing sulfite reduced CN- into SCN- and weakened the complexing ability of CN- with metal ions on the mineral surface, thus achieving a good activation effect on chalcopyrite and sphalerite. The results of this study can provide practical guidance in increasing the resource utilization ratio of cyanide tailings in gold mines, and thus contribute to alleviating environmental problems caused by stockpiling cyanide tailings. INTRODUCTION Cyanidation, the most widely used technology for extraction of gold, has several advantages such as high recovery, process maturity, low cost, etc. According to available data, the annual discharge of cyanide tailings from China's gold mines exceeds 20 million tons (Li et al., 2011). Lower grades of exploitable gold ore entail increased discharge of cyanide tailings. Huge quantities of cyanide tailings are regarded as waste and stored, resulting in significant wastage of land resources. Moreover, residual beneficiation reagents, cyanide ions, and heavy metal ions in cyanide tailings cause severe pollution of water and land (Laitos et al., 2013; Donato et al., 2007; Mudder and Botz, 2004). In addition, cyanide tailings often contain valuable elements such as gold, silver, copper, lead, zinc, sulfur, and iron, which, if not recycled, would result in considerable wastage of resources. Hence, it is imperative to study the reduction and safety of cyanide tailings, and the mineral resources present in them."

Jan 1, 2018

By G. Bulut, Ü. Yenial

"Heavy metals contamination in aqueous systems can be found in a variety of industries, in particularly mining, metal processing, finishing and plating. Water containing more than 0.5 ppm heavy metal considered as a toxic due to harmful effects on health. The major techniques employed for heavy metal removal from industrial wastewaters include precipitation, reduction, ion-exchange, and adsorption. Adsorption is a heavy metal removal method for aqueous systems. As a common adsorbent, activated carbon has been used in treatment but it is ineffective on some elements. Thus, there has been a research for developing highly effective and selective adsorbents. In this study the adsorption of lead and arsenic ions on to coal waste and red mud waste was studied. The experimental parameters were determined as pH, equilibrium time and the initial concentrations, activation by heat treatment and the blend of adsorbents. According to their adsorption capabilities, red mud was found to adsorb lead and arsenic ion with high efficiency but coal waste did not adsorb arsenic ion. However the binary adsorptions of these ions were enhanced the adsorption efficiencies. In addition the blend of coal waste and red mud affected the adsorption efficiency. INTRODUCTION As a result of rapidly developing industry and excessive use of water resources, the need of clean water and wastewater management appear as a problem. Wastewater recycling activities and researches come to the fore for an effective use of wastewater. Recycling of wastewater, which contains heavy metals harmful to the environment and human, is a difficult process. Heavy metals are generally divided into three categories: toxic metals, precious metals, radionuclides. Wastewaters from various industries, containing heavy metals, are the main polluters of water and soil. Although their toxic structures, heavy metals are used extensively in industry as they have technological significance. Usually mining industry, metal industry and industrial organizations produce heavy metal containing wastewaters (Volesky 1990, Ting and Lawson 1991, Bishop 2002)."

Jan 1, 2018

By N. D. Ilankoon

"The use of thiosulfate as an alternative lixiviant for cyanide to treat complex refractory ores followed by the use of ion exchange resins (IX resins) for gold recovery has become an industrial reality. In this study, polyethylenimine (PEI) coated iron oxide magnetic nanoparticles (MNPs) were used to recover gold from the leaching solutions that consist of calcium thiosulfate, copper and gold. The gold loaded MNPs were easily separated from the solution using an external magnetic field. Proposing a novel adsorbent with characteristically easy solid-liquid separation, to recover gold from synthetic thiosulfate leaching solutions and gold elution and reuse of MNPs were the main objectives of this study. Adsorption isotherm studies revealed that the data fitted both Langmuir and Freundlich isotherm models equally well. The maximum adsorption capacity was 18.5 mg/g at pH 8 and 50?C. According to thermodynamic studies the physisorption process was exothermic and spontaneous. Gold and copper elution, and the regeneration and reuse of the nanoparticles were investigated and promising results were obtained. Different elution systems comprising sulfites, chlorides, glycine, EDTA (ethylenediaminetetraacetic acid) and sodium hydroxide were considered. Among them, EDTA for copper elution and NaOH for gold elution were the most efficient eluants. Regeneration and reuse studies revealed that the MNPs can be used for several cycles without significant performance loss. INTRODUCTION Although cyanidation has been used for gold leaching for more than 100 years, some major drawbacks associated with cyanidation have led to a quest for alternative lixiviants for gold leaching. Cyanide is ineffective in treating carbonaceous refractory ores as gold cyanide complex is adsorbed onto the native carbon in the ore itself known as preg-robbing. On the other hand environmental concerns associated with cyanidation drives the need for environmental friendly alternatives for cyanide. As of today, thiosulfate is known to be the most extensively studied and most promising alternative lixiviant for cyanide in both technical and environmental perspectives (Aylmore and Muir 2001, Oraby 2009)."

Jan 1, 2018

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition. This article is devoted to the promotion of the concept of mineral processing in modern realities of the deficit of high–grade ores and increase in their demand. Normative and methodical documentation for specific types analysis with the definition of the field of application are presented in this paper. . For example, the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore field were tested. The development of mineralogical methods and testing of specific raw materials are shown. The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field.INTRODUCTION A highly intense production of many types of mineral deposits results in gradual depletion and of mining-geological and mining-technical conditions of various ore reserves ?. Relatively easily accessible and rich deposits are getting depleted in the first place, and it is necessary to involve low grade and refractory ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral deposits, creation of scientific and methodological pre-requisites for solving the problem of rational development of mineral deposits, maximum extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and ores.The article is aimed at updating tasks that should be addressed within the applied mineralogical research: – forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of properties ore, – interactive monitoring of these indicators by mineralogical and analytical methods;"

Jan 1, 2018

By D. Z. Wang

A red copper plate, discovered in the ruins of Dachengshan in Hebei province, was recognized as a forged one rather than a cast one, which means it was probably made from natural copper during the Longshan Culture period (2200~2208 BC) in the Chinese history. The copperware, found in the Niangniang Tai relics in Wuwei city, Gansu province, contains 99.6% copper and 0.4% Sn, Pb, Sb and Ni, which was guessed to be made during the Qijia Culture about 2000~ 1900 BC in the Chinese history in the late Neolithic before Shang dynasty. This shows that Chinese ancestors were able to distinguish, sort and use some native metals and minerals more than 4000 years ago.

Jan 1, 2014

By B. Suresh

Iron ore in Bellary-Hospet region is friable in nature and generates a significant amount of micro-fines (-150 µm) during mechanized mining, handling and processing. Present beneficiation practice generally employs spiral classification followed by hydrocycloning to remove slimes (-15 µm). The iron ore fines, beneficiated at JSW Steel Ltd., Karnataka generates tailing having 48-52% iron content in the form of slimes, which accounts for 50 to 55% by weight with respect to classifier overflow. The loss of iron as slime is considerably high. In this context, laboratory studies were carried out with different combination of beneficiation techniques with an objective to develop an efficient flow sheet to achieve better product grade and recovery from classifier overflow. The results revealed that de-sliming process by hydrocycloning in combination with either magnetic separation or froth flotation leads to increased iron loss in tailing. Based on investigation it is observed that forward flotation is beneficial over the reverse flotation. The experimental approach of forward flotation on classifier overflow followed by magnetic separation on flotation tailing resulted in overall product grade of 62.9% Fetotal and 70.3% yield. The tailing contains 34.6% iron, which accounts for 29.7% by weight with respect to classifier overflow.

Sep 1, 2012

By Q. W. Jiang

This paper presents a new process for producing industrial magnesium sulphate using waste water from titanium white plant and magnesium oxide from calcinations of magnesite ore as raw materials. With the laboratory experimental equipment, the waste liquid and magnesium dioxide react effectively at ambient temperature and under atmosphere pressure. Via the press filter, a clear liquid predominately containing magnesium sulphate is obtained. It is further evaporated and crystallized by cooling, separated by centrifuge and dried. Consequently a high quality of industrial magnesium sulphate is achieved as the final product. In the course of process, as the majority of valuable component (SO42-) is recovered in the final product, most of impurities from waste acid is being removed into the by- product. With the simple operational process, it is possible for titanium dioxide plant to resolve the environmental problem completely and benefit from the industrial magnesium sulphate product as well. The filter cakes containing valuable elements such as Mg, S, Fe, Mn, V, Ti are by-product proposed to be used for manufacture of agriculture fertilizer particularly for peanut planting.

Jan 1, 2014

By Regis Texeira, Leopoldo Gutierrez, Vicente Hernandez, Caludia Vidal, Lina Uribe

"Molybdenum is currently the most important by-product of Chile´s copper mining industry. This mineral has gained international relevance over the years, because of its price. At mining deposits in Chile, copper and molybdenum are extracted together and then separated in a concentration process consisting of several flotation steps using sodium hydrosulfide (NaHS) as copper depressant. However, there are environmental issues related to the potential emisions of toxic hydrosulfide gas and bad odours, which affects nearby communities and suppose a risk for operators. This problem has led to the need for development of new technologies to eliminate the use of NaHS in the process of selective flotation of Cu and Mo minerals. In this work, results of flotation tests in which lignin derivatives reagents are used to obtain the selective separation of Cu and Mo minerals by flotation are presented. In this technology molybdenite is depressed by the action of lignin derivatives (lignosulfonates), while copper sulfides remain hydrophobic and float. The use of lignin derivatives in the selective flotation of copper molybdenum minerals represents a non-toxic alternative to NaHS.INTRODUCTIONSeparation of copper sulfides from molybdenite is commonly achieved through a two-stage flotation process. In the first stage the collective flotation of copper sulfides and molybdenite is promoted to generate a collective concentrate which is then treated in a second stage with sodium hydrosulfide (2.5-3.0 kg/t NaSH) to depress copper sulfides flotation without affecting the flotation of molybdenite. As a result a copper concentrate with 30-35% Cu, and a molybdenum concentrate with 50-52% Mo are generated. Although this process is widely used at industrial level, environmental issues related to the risk of H2S generation and bad odors have always been a concern. Thus there is a need in the industry for a more environmentally friendly process to separate copper sulfides and molybdenite."

Jan 1, 2018