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By S. J. Liu

The conventional collector for bauxite mineral is oleic acid, which is highly insoluble and must be used in high dosage in bauxite flotation operations, that is the great drawback of oleic acid in use. A series of hydroxamic acid were synthesized, and their collecting ability to certain minerals in bauxite: diaspore, kaolinite were studied. The collecting power of various reagents to diaspore in an incremental sequence were shown as follows: benzyl hydroxamic acid<amylic hydroxamic ac-id<heptylic hydroxamic acid<oleic acid<octylic hydroxamic acid; while the incremental sequence of the collecting power to kaolinite was like this: benzyl hydroxamic acid<amylic hydroxamic ac-id<heptylic hydroxamic acid<octylic hydroxamic acid<oleic acid. It could be seen that octylic hydroxamic acid had the capability of high collectivity and good selectivity, and octylic hydroxamic acid was chosen to use in the following experiments. Reduced zeta potential showed the adsorption of the anionic collector on the mineral. By the adsorptive capability and IR tests, the adsorption of octylic hydroxamic acid on diaspore was determined to be chemical absorption, which was greater than that of oleic acid, as it was physical absorption. Results of floatation experiments on manually mixed minerals indicated that the collectivity and selectivity of octylic hydroxamic acid were better than oleic acid.

Jan 1, 2014

By A. Luszczkiewicz

An innovative hybrid technology for beneficiation of difficult-to-process sedimentary copper ores comprising acidic leaching stage of the feed combined with subsequent flotation has been presented. Acidic leaching, preceding the flotation process, plays a beneficial role of efficient chemical grinding for liberation of copper sulphide minerals finely disseminated in the copper-bearing carbonate-shale rocks. The process was applied on a fully industrial scale. Flotation results were analysed for both chemically modified and unmodified flotation feeds. After several months of industrial scale operation, it was found that both metals recovery and concentrate grade remarkably increased as a result of application of chemical modification of the flotation feed. Beneficial effects of chemical pre-treatment of flotation middlings on selectivity at a comparable concentrate yield in industrial flotation scale, revealed a considerable increase of the total copper recovery by 3.5percent. Based on the industrial and laboratory investigations we consider a further development of the process and introduction of hydrometallurgy for better recovering of metals from low-grade copper concentrates

Sep 1, 2012

By Zhen Hu, Chenghang Wang, Jianjian Zou, Xiujuan Li, Hanwen Li, Tai Wang, Baoxu Song

A rare earth deposit in Sichuan, China is rich in wulfenite in addition to bastnaesite and barite, and the deposit has already adopted high intensity magnetic separation technique to pre-enrich the rare earth minerals, during which the wulfenite and barite have been left in the non-magnetic product. Because the chemical composition of wulfenite is only 24.17% Mo and 42.15% Pb, it is very hard to obtain qualified lead or molybdenum concentrates by physical separation process. To pre-concentrate the wulfenite, flotation has been first introduced, and by using 100g/t GY-7 as dispersant, 1500g/t CP-1 as depressant and 160g/t GY-4 as collector, a floatation concentrate assaying 15.52% Mo with a recovery of 86.12% was obtained. Then a leaching process was conducted by using 1.2mol/L Na2S as leaching agent, and molybdenum can be translated into sodium molybdate in the solution with a leaching recovery of 99%. To recover rare earth oxides (REO) and lead from the leaching residue, a magnetic separation process has been conducted. Above all, by the whole process, the molybdenum recovery reaches 86.16% in the sodium molybdate solution, and a lead concentrate assaying 54.59% Pb with recovery of 27.99% could be obtained.

Jan 1, 2014

By Gulsen Tozsin, Ekrem Kalkan, Taskin Oztas, Elif Agirman Akturk, Ercument Koc, Ali Ihsan Arol

Marble wastes are generated by quarries (marble quarry waste-MQW) and processing plants (marble cutting waste-MCW). The large amount of marble wastes is becoming serious problem for industry and environment because of discarded into rivers and lagoons, without any treatment. Marble wastes can cause environmental problem and economic loss if the waste is not used. However, this type of wastes has a good potential to be used as an amendment for the neutralization of acid soils. In this study, MQW and MCW were applied to an acid soil at different rates and their effectiveness on neutralization was evaluated by a laboratory incubation test. The results showed that soil pH increased from 4.71 to 6.36 and 6.84 by applications of MCW and MQW, respectively. It was suggested that MQW and MCW could be used as soil amendments for the neutralization of acid soils, and thus the negative impact of marble wastes on the environment could be reduced.

Jan 1, 2014

By S. L. Gubin, T. V. Ignatova, A. V. Levshin, D. O. Sharkovsky

"Flotation process applied for concentration of unoxidized ferruginous quartzites by PJSC Mikhailovsky GOK (MGOK) is based on wet magnetic separation of strong magnetic minerals. However quality of the resulting concentrate (Fe65-66%) is insufficient for production of metallics. Quality upgrade of magnetite concentrate via flotation has been implemented by MGOK to produce premium quality magnetite concentrate.Flotation is a challenging process due to sensitivity to varied amounts of reagents, fine and coarse mineral ratio, particle contact (retention) time and temperature of feed. Tomah’s PA-14 reagent (USA) has proven efficient for application in flotation of MGOK’s magnetite concentrate.Objective of this work is to select and prove applicability of selective agents for flotation upgrade of magnetite iron ore concentrate.Series of flotation tests has been carried out with application of new highly selective collecting agents produced by Akzo Nobel (Sweden), Clariant (Germany) as well as Akzo Nobel’s and Tomah’s cationic collector mix to improve performance efficiency of flotation process. Tomah’s flotation agents and Akzo Nobel’s Lilaflotproved to be the most effective for purposes of concentrate quality upgrade to Fe69.0% via flotation.Testing Method: Following scientific research methods were applied for testwork: system analysis, mathematical statistics, observation, comparison, trial (experiment).To determine key process factors a series of pilot tests was carried out. Most of the testwork was performed by PJSC Mikhailovsky GOK’s Central Process Laboratory.Work Results:-optimized flotation performance modes were defined to ensure production of three types of low-silica concentrate, i.e. containing SiO25%, SiO24% and below SiO23% by weight. Most efficient selective agents applicable for flotation have been defined. Mixture of higher aliphatic amines has proven to intensify selective flotation of quartz. It enables higher yield of chamber product maintaining desired quality of concentrate.Achieved process operation and performance factors have been revaluated.Value for Advancement and Expansion of Mineral Processing:Flotation of concentrate has enabled expansion of PJSC Mikhailovsky GOK’s production capacity, improved production quality, helped to maintain sustainability and competitive advantage of the company."

Jan 1, 2018

By Renato S. Costa, Afonso H. Martins, Flávia D. Mendes

"This paper presents some important aspects regarding the ion exchange treatment of an Ni and Co sulphate acidic liquor using chelating resins. Chelating resins possessing iminodiacetic or bis-picolylamine functional groups were compared in terms of nickel and cobalt recovery. The experimental resin with bispicolylamine functionalities (Dowex M4195) was evaluated with respect to Ni and Co uptake, and compared with Rohm &Haas commercial chelating iminodiacetate acid resin. The Rohm & Haas chelating resin, Amberlite IRC 748, with its weakly acidic groups, did not work in acidic solution but exhibited good results at pH 4 and above. The resin that efficiently removed metals from high acidic solutions was the bis-picolylamine resin. Maximum nickel uptake values ranged between 85 g and 112 g Ni per Kg of resin.The experimental part dealt with the working conditions, resin characteristics and the influence upon the resin maximum exchange capacity of the following factors: nickel concentration, temperature, pH and resin-to- solution ratio. Based on the experimental data obtained, it has been proposed a innovative technological treatment."

Jan 1, 2003

By Li Tianxia, Zhou Jing, Zhu Yimin

"A typical low-grade of high sulfur bauxite fr contains 54.71% Al2O3, 11.35% SiO2 while the ratio of aluminum and silicon was 4.25, and harmful components such as Fe and S graded 7.3% and 1.33% respectively. The ore is characterized by complex mineral compositions, fine dissemination of particle size of pyrite and diaspore, low desulfurization efficiency, and difficult separation of aluminum and silicon. In order to improve the degree of concentration, recovery and desulfurization efficiency on the basis of process mineralogy studies, the floatation behavior of high sulfur bauxite in the process of desulfurization and desilication were studied through laboratory tests and pilot plant tests. KEYWORDS high-sulfur bauxite; low grade; flotation; desulfurization;desilicication INTRODUCTION In order to solve the selection problem of bauxite mine area, we carried out technological mineralogy, laboratory test, small-expansion Dalian test to solve the problem of the refractory ore. Main research contents and conclusions were presented as followings :(1)Process mineralogy research shows: the main mineral components include diaspore, kaolinite, chlorite, pyrite, limonite. (2)Batch flotation tests indicated that slime can be dispersed well during desulfurization floatation when Na2CO3 was used as modifying agent. (3)Poilot plant tests shows that Batch flotation tests results are correct. 2?PROCESS MINERALOGY 2.1 Chemical Composition of Ore 2.1.1 Spectral Analysis of Sample The results of the semi-quantitative analysis of X-Ray -fluorescence spectra of the original ore are shown in Table 2-1. The results of spectral analysis show that the main components of the sample are O, Al, Si, followed by Fe, Mg, Ti, S and so on, while the content of other elements is very small. The value is Al, and maybe Ti, for bauxite, while Fe and S are unfavorable elements, and Si and Mg and Ca are the main impurity elements."

Jan 1, 2018

By C. B. Wu

This paper presents an analysis of comminution behavior of using cast iron segment (CIS) as fine grinding media with comparison to conventional steel ball. Grinding experiments utilize just one-size medium and mixed size media in laboratory were carried out and its efficiency is expected to be improved. The results show that no matter whether one-size medium or mixed size media employed, grinding efficiency of CIS media can be considerably equal to that of steel ball, on the other hand, grinding product by two kinds of media can conform to Robin-Rammler?s size characteristic curve and distribute in function of . )exp(100nbxy-= Comparing with steel ball, the milling capacity with CIS media could be increased up to about 8.6 percent, overcomminution decreased 3.96 in percentage and qualified size increased 3.98 in percentage in case of grinding fineness retained. At the same time, due to the improvement of grinding product size characteristic and its metal distribution characteristic, the grade and recovery of easy to separation size increased 0.24 in percentage and 6.47 in percentage respectively. Based on these results, the CIS media can be employed as novel fine medium for grinding process substituting for steel ball.

Jan 1, 2014

By Liu Fan, Shang Yanbo, Wang Zhongming

"Besides valuable metals of Cu, Sn, WO3, Zn, there are S, Ag, CaF2, In and so on in a complex ore deposit in south China (which belongs to Hu Nan Shizhuyuan Non-ferrous Metal Limited Liability). Although it proved reserve amounts to 3.5×107 ton, its crystal character limits its utilization in large-scale. It features complex relationships between valuable minerals, finest crystallized particle size, low-graded valuable metals (Cu 0.30%, Zn 0.5-0.7%, Sn 0.2%, W<0.1%). If only tungsten minerals are considered, it means WO3 grade is too low (the cut-off grade of WO3 is 0.1% in China). Only Cu and Sn minerals are recovered from 2006 and Cu recovery is less than 70%, Sn 15-20%. Other valuable metals of W, Zn, S and CaF2 were lost in the tailings. To make good use of the ore, the technology of fully recovering Cu, Sn, W, Zn, CaF2 and rare metals are in urgent need. After systematic researches, the flow sheet of "bulk flotation of Cu-Zn minerals at first, then Cu-Zn separation, then recovering sulphide by flotation, then recovering iron minerals by magnetic separation, then bulk flotation of Sn-W minerals after desliming" is developed. Furthermore, specific Sn-W collectors of BK411 and BK412 are applied into the processes and better indexes are obtained. The industrial indexes are listed as followings: the content of Cu, Zn, Sn, WO3 of ROM ore is 0.31%, 0.65%, 0.13%, 0.03%; Cu and Zn recovery are 82.23% and 37.79% respectively; 63.76% of Sn and 34.34% of WO3 go into the Sn-W bulk concentrates. Economic benefits are remarkable."

Jan 1, 2014

By Maurício Torem, Gabriela Huaman, Antonio Merma

The purpose of this review paper is to succinctly present the most significant works related to Mineral Processing and Environmental Bioremediation and developed by the Mineral and Environmental Technology Group (METG) of the Materials Engineering Department of the Pontifical Catholic University of Rio de Janeiro (PUC-Rio). In mineral processing it was emphasized the use of the Rhodococcus opacus bacteria as a bioreagent in the bioflotation of some mineral samples (magnesite, calcite, hematite, quartz and apatite). The adsorption of the bacterial cells on the mineral surface can be due to specific and/or non-specific interactions, which will depend on several factors, as their surface charge and hydrophobic character. The zeta potential evaluation of the mineral particles before and after interaction with the R. opacus cells showed that the biomass modified the zeta potential profiles of the minerals, which confirm the adsorption of bacterial cells on the mineral surface. Moreover, the bacterial cells adsorbed caused a change in the mineral flotability which is related to a change in their hydrophobic character, thus, the mineral bioflotability was found to be dependent on the pH and the bacterial concentration. On the other hand, the environmental bioremetiation assessed the biosorption potential of three metal ions (lead, copper, and cobalt) by four different biomass Streptomyces lunalinharesii, Rhodococcus opacus, Rhodococcus ruber and coconut shell powder. For this purpose, biosorption process was characterized under different operating conditions such as initial pH and biosorbent dosage. The Freundlich and Langmuir isotherm models were applied to the equilibrium data obtained at different concentration.

Jan 1, 2014

By V. A. Luganov

Methods of treatment of pyrite concentrates differ, depending on the content of pyrite and non-ferrous metals: oxidation roasting, sulphatization roasting, smelting, direct hydrometallurgical treatment and so on. Existing technologies do not provide for high recovery of metals, expenses associated with existing technologies are high, and environmental issues, associated with the existing technologies need serious attention. We have developed universal technology of the activating-dissociating autogenous roasting of pyrite concentrates using air based, or air, enriched with oxygen, blow. The basic process is taking place in accordance with the following reaction: (1-x)FeS2 + (1-2x)O2 = Fe1-xS + (1-2x)SO2 +Q The products of this reaction are pyrrhotinized cinder and roasting gases, rich in SO2 (up to 18 % in case of air blow) and poor in SO3, that contain up to 1 % of elemental sulphur. Cinder contains different forms of pyrrhotite. These forms of pyrrhotite differ by its content (from Fe0.843S to Fe0.945S), thermodynamic, magnetic (from 4.10-1 to 3.6 SI units), flotation properties (with pyrite dissociation the ?-potential of the product is moving towards more electrically positive charge, from 0.95 for pyrite to 0.2 for dissociation products) and other properties that depend on the conditions of roasting. The combination of pyrrhotizing roasting with different methods of cinder treatment allows to increase the level of sulphatization of non-ferrous metals during the roasting; reduce the amount of blow used during the processing; reduce dust losses to the gas phase; reduce the capacity of gas cleaning system and increase resistance to corrosion of the gas-treatment system, used for the production of sulfuric acid from pyrites. This combination of treatments also allows to use magnetic separation and flotation for separation of ferrous and non-ferrous metal compounds during cinder treatment; perform de-arsenation of arsenic containing concentrates and by-products. Pyrrhotinized cinder may be treated by oxidizing and non-oxidizing hydrometallurgical methods. Keywords: Pyrite, polymetallic ores, sulphidization roasting, pyrrhotite, magnetic separation, arsenic sulphide

Sep 1, 2012

By X. Q. Cao

As the second largest phosphate resource in the world, Chinese phosphate ores generally grades with low of P2O5. The presentation of beneficiation test on the low grade of phosphate rock in this paper may be used for a reference for development and utilization of the similar reserves. The ore is a marine sedimentary phosphate rock containing low grade of P2O5 and high content of MgO and R2O3; The banded structure shows its suitability for heavy medium separation. The laboratory heavy liquid testing results indicate that as specific gravity of the heavy liquid is 2.85 g/cm3, a rougher concentrate assaying 28.71% P2O5 could be obtained while the rougher tailings contain only 4.47% P2O5. When the combined process with heavy liquid separation followed by direct & re-verse flotation is employed to treat the feed containing 21.15% P2O5, 3.79% MgO, 1.86% Fe2O3, 3.66% Al2O3, 23.75% A.I, and specific gravity of heavy liquid is 2.84 g/cm3, the optimum mesh of grind is 67.5% minus 200 mesh, a phosphate concentrate contained 32.51% P2O5, 0.48% MgO, 0.81% Fe2O3, 1.69% Al2O3 can be produced at a yield of 55.24%. The concentrate P2O5 recovery is 85% with which quality comply with the Class A specifications for production of phosphate fertilizer.

Jan 1, 2014

By Shibayama A.

In this research, an investigation of a process to selectively remove arsenic (As) and antimony (Sb) contained in enargite (Cu3AsS4) and tennantite/tetrahedrite ((Cu1,Fe)12(As,Sb)4S13) copper resources by leaching and precipitation were performed. First in the leaching process, the target was to selectively leach As/Sb and reduce their contents in the ores to <0.5 wt% followed by a second process to remove As/Sb dissolved in solution for environmental control. Enargite ore contained 3.65 wt% As while tennantite/tetrahedrite ore contained 5.40 wt% As and 4.85 wt% Sb. Alkaline leaching using NaHS?NaOH media at varying experimental conditions (temperature, pulp density, time, reagent concentrations) were performed to investigate the process. As/Sb precipitation studies were also performed to control high As/Sb concentrations in leach solutions by using elemental sulphur (So). Results from leaching studies showed that over 99% of As/Sb in the impure copper ores can be removed and their contents in the final solids reduced to <0.5 wt%. It was also established that such very high leaching could be achieved at 80°C within 1?6 h and pulp densities as high as 1000 g/L. The study also revealed that leach solution containing very high As/Sb concentration ranging from 5 to 20 g/L can be used as fresh solution for leaching of fresh ores until concentrations exceeding 35 g/L when it was sent to precipitation circuit for As/Sb removal. Addition of elemental sulphur at 90°C and fast cooling to 30°C allowed over 60% As/Sb precipitation and removed as Na3AsS4 and solution with reduced As/Sb concentration to leaching circuit for continuous use. Keywords: Enargite; Tennantite/Tetrahedrite; Selective Leaching; Precipitation; Sodium hydrosulfide;

Sep 1, 2012

By Pan, Jian, Siwei Li, Deqing Zhu

"It is great significance to realize the efficiently and comprehensively utilization of iron, manganese and aluminum from refractory high-aluminum and high-manganese iron ores. Aimed at the two types of low grade refractory iron ores, mineralogical characteristics were studied. The direct reduction behaviors and evolution of mineral compositions of single iron ores and their blended ones were analyzed, and the corresponding reduction mechanisms were demonstrated. The results showed that only a part of iron oxides in high-aluminum ore are transformed to metallic iron after reduction, while the other react with aluminum and silica to form fayalite and hercynite which are difficult to be reduced. For the high manganese iron ore, most iron oxides can be reduced to metallic iron and manganese oxides can combined with aluminum-silica minerals to form galaxite and tephroite, promoting the reduction of iron oxides. Co-reduction results demonstrate that reduction of high- aluminum ore can be promoted by adding with high-manganese ore. Metallization and metallic iron grains increase dramatically by elevate high-manganese blending ratio. At the ratio of 60% high- manganese iron ore in the pellet feed, iron-slag separate well with a slag assaying 28.51%~36.35% Al2O3 and the recovery of iron and manganese can be reached 93%, respectively. The high-aluminum rich manganese residue was recycled with H2SO4. INTRODUCTION The growth of the Chinese iron and steel industry has been pushed forward by its rapid economic development in recent years, and 1126 million tons of iron ore have been consumed in 2014, where 933 million tons were imported according to the data from World Steel Association [1]. However, iron resources are limited, and especially the reserves of high-grade iron ores are declining, so it is of significant importance to optimize the mining rate of iron resources [2] and to utilize low- grade refractory iron resources, such as high-aluminum iron ore."

Jan 1, 2018

By E. L. Chanturiya

During the mineral processing of pyrites sulphide ores of some deposits of Russia loss of gold with tailings and pyrite concentrates amounts up to 40%~90%. The problem of selective allocation of gold-bearing pyrite is crucial. There are 4 mineralogy-technological groups of pyrite determined in copper-zinc sulphide ores, based on the increase of contents of gold in pyrite. The gold associated with group 4 pyrite contents of 85% the total mass of gold found in the pyrite. The flotation behaviour of the enriched fractions of pyrite (98%), of the allocated from the ore of Gay deposit, were studied essentially in various conditions ?? and the charge of Butyl xanthogenate of potassium (ButX). Some products of selective pyrite flotation were investigated by methods of scanning electronic microscopy, energy-dispersive and X-ray spectral microanalyses, definition of specific resistance and thermoelectric moving force.

Jan 1, 2014

By G. Mucsi, F. Kristály, Á. Rácz, É. Gregus, K. Bohács

"Stirred media mills are widely used in the industry for fine grinding. Most of the applications work in wet mode, however dry grinding in stirred media mill comes forward more frequently nowadays. The present paper deals with the differences and similarities of the wet and dry grinding in stirred media mill from energetic and mechanochemical point of view as well. Grinding experiments in batch stirred media mill were carried out with different materials. During the experiments zeolite and kaolin were used as feed material. The grinding experiments were carried out at different stress energy and stress number values; the grinding work was measured during milling. After grinding X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), particles size analyzes by laser scattering were carried out on the ground materials. As a result of the systematic grinding and analytical measurements a comprehensive comparison was carried out on the wet and dry grinding and their usefulness for mechanical activation in stirred media mill. INTRODUCTION The natural zeolites are crystalline hydrated aluminosilicates of alkali and alkaline earth characterized by the structure that contains frameworks responsible for the high cation exchange capacity (CEC) and absorption capacity. The frameworks are interconnected by cavities and resided by cations variable in size, coordinated by water molecules. Since zeolite comprises SiO4 and AlO4 tetrahedra interlocked by oxygen atoms that are situated in the structural nodes, their characteristics differ due to the varieties in the structure-directing agents and Si/Al ratio (Colella and Wise, 2014; Malekian et al., 2011; Terzic et al., 2017). The most common natural zeolite occurring in high amount, of industrial importance and involved in milling and MA is the clinoptilolite, in the literature equivalent to “natural zeolite” designated for high clinoptilolite bearing volcanic tuffs. Its amount in the host rock must reach ~ 40 % by weight to obtain the CEC and adsorption desired in its applications. In the highest quality rock might reach 80-90 % by weight (Favvas et al., 2016), but most often is the 40-60 % by weight content, associated with smectites, improving the CEC and adsorption of the tuffaceous rock. The application of such natural zeolites is problematic in many cases due to high silica (quartz, cristobalite and volcanic glass) content and beneficiation (concentration and extraction of pure zeolite) are not feasible. Thus, mechanical activation is a possible way to alter the other than clinoptilolite minerals generating high specific surface area and functionalized particle surfaces to enhance adsorption, reaction or particle adhesion. The zeolites easy availability and the utilization cost-effectiveness have prompted the research on their physicochemical and structural properties (e.g. adsorptive and molecular-sieve activity, heat resistance, and microporous cage structure) and finding new options for their application (Kusuma et al., 2013; Musyoka et al., 2014; Rida et al., 2013; Terzic et al., 2015b). Apart from the presence of exchangeable framework cations which are crucial for the adsorption ability, and a certain degree of pozzolanic reactivity. The thermal stability of dehydrated phases is another important characteristic for use of the zeolite in composite materials that are exposed to high temperature. Thereby, the zeolites found a wide application possibility in the design of the construction composites (Albayrak et al., 2007; Najimi et al., 2012; Vejmelková et al., 2015), as well as for resolving of the environmental protection issues like wastewater refining or heavy metal elimination (Gómez-Hortigüela et al., 2014) even from contaminated groundwater using passive methods like permeable reactive barriers (Gombköto et al, 2016). The grinding treatment of zeolite is a common and frequently applied procedure, both on laboratory (Bohács et al. 2017, Faitli and Czél, 2014)"

Jan 1, 2018

By Hong Zhong, Shuai Wang, Zhanfang Cao, Ting Dai

"Manganese is widely used in industries such as the steel industry and is now an essential element in modern industry. Technologies for the efficient and clean utilization of manganese resources must be developed and employed to ensure the sustainable growth of the manganese industry. Our research focuses on the use of beneficiation technologies to improve the grade of ores or the replacement of low-grade manganese carbonate ores with high-grade manganese oxide ores, and thus, to reduce reagent and energy consumption and the yield of electrolytic manganese residues from metallurgical processes; the study of leachate purification technologies; the study of electrochemical behaviors during electrolysis and energy-saving electrolysis methods; the development of chromium-free passivators as alternatives to the highly toxic potassium dichromate passivator; the non-hazardous treatment and resource utilization of electrolytic manganese residues and other manganese by-products; and the development of new manganese products. INTRODUCTION Manganese is widely used in the steel industry, nonferrous metallurgy, the chemical industry, electronics, batteries, agriculture, etc. Globally, more than 90% of manganese is consumed by the steel industry, and thus, it is said that ""No steel industry without manganese""(Banerjee et al. 2017, Zhang et al. 2017). Current manganese resources mainly include manganese ores, marine manganese nodules and waste catalysts. The total global output of manganese ore from land deposits is 18 million tons (metal volume), and the reserves, most of which is in the form of manganese oxide ores, are estimated to be 620 million tons (metal volume). More than 400 manganese ore deposits with a total reserve of 1.22 billion tons have been discovered in China. These deposits are predominantly manganese carbonate ores. Marine manganese nodules exist on the surface of the deep seabed at depths of 2000-6000 m. These nodules, which are also called polymetallic nodules, manganese balls, manganese aggregates and manganese tumors, are mainly composed of iron and manganese oxides. The total reserves of these resources add up to more than 3 trillion tons. Furthermore, the manganese in manganese-containing catalysts can be recycled after they become inactive."

Jan 1, 2018

"The global demand for the copper metal is continuously increasing however, the high-grade copper ore deposits are constantly depleting. As a result, ore bodies with complex mineralogy characteristics and rich in arsenic-copper bearing minerals are increasingly processed. Arsenic-copper sulphides such as enargite can represent a significant amount of arsenic in concentrate, which causes high financial penalties by smelters. On the other hand, arsenic (As) is a highly toxic inorganic pollutant, which causes human health and environmental problems. Recent research studies have demonstrated promising results showing the possibility of separating arsenic-copper sulphides from copper sulphides using controlled pulp potential (Eh) flotation at laboratory scale. However, the selective removal of arsenic-copper minerals in real ore systems is not well understood. Two ore samples were selected from the Tampakan copper-gold deposit located in the Philippines named the HAS (high arsenic sample) and the LAS (low arsenic sample) samples and the mineralogical analyses were performed on both samples. The floatability of enargite in a batch flotation system under controlled pulp potential conditions was investigated for the HAS and the LAS samples. It was observed that it is possible to selectively separate enargite from other copper minerals after reducing the pulp potential to about -200 mV SHE at pH 11 in the LAS sample. However, no separation between enargite and other copper minerals was observed at a reducing potential for the HAS sample. Mineralogical analyses and surface chemistry studies were undertaken for both samples to find out the reasons for different observations. This study has an important implication in sulphide flotation to achieve sustainable development in the utilisation of arsenic-copper mineral resources. INTRODUCTIONAs the demand for copper is increasing, the extraction and development of resources including complex deposits is becoming necessary. These complex deposits often have issues such as: lower grade ores, floatable non-sulphide gangue, very fine-grained ore and therefore poor liberation and significant regrinding, mixed copper mineralogy, complicated galvanic interactions, economic levels of gold and silver, and high levels of impurities such as arsenic. There is currently no established methodology for separating arsenic-bearing copper minerals from other copper sulphide minerals by flotation. The possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp has been shown in previous studies. However most of these studies were conducted on single mineral systems and the selective removal of arsenic-copper minerals in complex ore systems is not well understood. The flotation behaviour of arsenic-bearing minerals within complex ores differs significantly from that of pure mineral systems due to the effects of mineralogical composition, the degree of liberation, and the surface oxidation. The understanding and manipulation of these effects can lead to improvements in the selective flotation recovery of arsenic-bearing species from complex ore systems."

Jan 1, 2018

By C. H. Zhou

Cryogenic grinding of Printed Circuit Board will bring less pollution, reduce energy costs, smaller particles, regular particle size, efficient process, separation various materials due to different fracture toughness. Systemic studies of recycling discarded Printed Circuit Board (PCB) by low-temperature modification and cryogenic grinding have been made in this paper. Firstly test mechanical property of PCB at different low-temperature, including impact strength, flexural strength, and shear strength. Do experiment on the power consumption of different cooling temperature, The results show that the average power consumption is lower between -30? to -60? and the average power is decrease in evidence at -30?. Use ZKB type double roll shear crusher to crush PCB to 20mm×20mm particle size, in a temperature range of -10 ~ -30? Used R type mill to grind sample to minus 3mm under different working condition, the average power consumption is decrease in evidence from -10 ? to -30 ?, power consumption is the lest at rotational speed is 1180rpm.

Jan 1, 2014

By Jacek Kolacz

A new sensor based sorting system has been developed, based on complex image analysis, where an image texture and a shape pattern is considered for identifying particles for separation. The sorting system employs different images generated by visual light and X-ray to provide maximal information about processed particles. Application of X-ray makes it possible to analyse the internal structure of the particles, which provides a 2D image with complicated texture, however, which contains valuable information. The advanced system for the texture and the pattern recognition is applied to analyse these images simultaneously, to provide the required identification of the particles for efficient separation. The mathematical models applied during identification and separation, are assisted by high speed calculations being specially optimised for this kind of process. This allows sorting with high capacity and high accuracy, which is critical for practical applications in mineral processing. The paper describes a number of tests during sorting of iron ore and coal with high separation efficiency.

Jan 1, 2014