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Anionic, cationic and cationic/anionic flotation is widely used in the concentration process for low-grade oxidized zinc ores. In the cationic flotation route, sodium silicate is used as a depressa...

An integrated hydrometallurgical process was used for the zinc leaching and purification from a zinc ore containing 9.75 wt% zinc. The zinc minerals in the ore were hemimorphite, willemite, and calcophanite. Main gangue minerals were quartz, goethite, hematite, and calcite. Central composite design (CCD) method was used to design leaching experiments and the optimum conditions were found as follows: 30% of solid fraction, 22.05% sulphuric acid concentration, and the leaching temperature of 45 °C. The PLS containing 35.07 g/L zinc, 3.16 g/L iron, and 4.58 g/L manganese impurities was produced. A special purification process including Fe precipitation and Zn solvent extraction was implemented. The results showed that after precipitation of iron, Zn extraction of 88.5% was obtained with the 2 stages extraction system composed of 30 vol% D2EHPA as extractant. The overall Zn recovery from the ore was 71.44%. Therefore, an appropriate solution containing 16.6 g/L Zn, 0.05 g/L Fe, and 0.11 g/L Mn was prepared for the electro-winning unit without using the roasting and calcination steps (conventional method), which result in environmental pollution.

The advent and development of new technologies that will provide better yields, cleaner and a safer environment is a global challenge for the researchers. Traditional solvents used in extraction of minerals are at many times hazardous thereby constituting threats to the ecology. The work reports the direct bioleaching of zinc sourced from Abakaliki-Ishiagwu complex zinc sulphide ore deposit. The sphalerite ore is predominant in Zn with other associated metals Pb, Cu, Fe, Ni, Sb, As, Cd, Au, V, Co, Ag, K, Al and Ca. It covers the pre extraction processes of mineral comminution (crushing and grinding); separation by froth flotation; and roasting. Agro-cyanide was extracted from cassava plant (Manihot esculenta Crantz) leaves and was used as leachant without any additive. The result of atomic absorption spectrometry (AAS) analysis of the leached liquor (pregnant solution) shows that lead, copper and iron in addition to Zinc, were obtained from the leached ore roast at 149.25 ppm (Zn), 79.25 ppm (Pb), 0.25 ppm (Cu) and 4.25 ppm (Fe) extraction after 21 days. Elongated contact of ZnO ore is not encouraging for Zn extraction as there is a decline in the quantity of Zn, Fe and Cu as the leaching time (days) increases. The mechanism of the Leach next faction is yet to be fully ascertained, hence the need for further work in the area.

Shaimerden oxidized zinc ore containing more than 21% wt.% zinc is studied in this work. When the first research on hydrometallurgical processing of this ore was conducted the authors of this research determined the following parameters for ore leaching: the size of ore reduction, sulfuric acid concentration, temperature, and leaching duration. These tests serve as a basis for zinc recovery from the given ore with a size of – 2.5 mm and a regime is recommended providing zinc recovery into solution at the level 93.5%. However, the production regime proposed for sulfuric-acid leaching of this zinc ore requires further development as this process is characterized by inadequate production, high energy consumption for heating leaching pulp, and considerable sulfuric acid consumption. In order to avoid these disadvantages the authors develop a production regime of four-stage sulfuric-acid leaching of Shaimerden ore – 1.0 mm in size. The regime developed in this article provides zinc recovery from ore into solution at the level 94.65% compared with the regime of sulfuric-acid leaching developed previously. At the same time, consumption of sulfuric acid for leaching is reduced by 22%, the leaching period is six times shorter, and energy consumed for heating leaching pulp is lower by approximately a factor of three.

The hexagonal plate lead iodide (PbI2), with band gap energy of 2.31 eV, was firstly synthesized from mixed sulfide-oxide lead and zinc ore by an in-situ reduction-selective leaching-precipitation ...

Pre-concentration of lead and zinc ore in Calcimin (public Co) which is done using heavy-medium cyclones (HMC) undergoes lots of inefficiencies and not in the desired manner. Considering th...

The present study deals with a microwave-assisted oxidation roasting oxide–sulphide zinc ore technology of with addition of manganese dioxide. Effects of roasting parameters such as MnO2 addition level, roasting temperature, and holding time are studied by using the Central Composite Design (CCD). Meanwhile, zinc calcines are characterized by phase compositions analyses(XRD), structure characteristics of minerals (FT-IR), micro-area chemical analyses (SEM-EDAX) and elemental valence bonding analyses (XPS), which prove to be in accordance with the CCD results. The optimum roasting conditions are decided as MnO2 addition level being 85.14 %, roasting temperature 680 °C, and holding time 41 mins, and oxidation degree of zinc can reach 88.22 %. Besides, when MnO2 addition level reaches a certain value, zinc will aggregate in a form of ZnMn2O4, one battery material.

The reuse of minerals from tailings is essential to generate less impact on the environment. The investigation of methods that aim to recover elements that can generate by-products from mining tailing has been studied, such as, for example, the zinc beneficiation tailing. The tailing acquired in the flotation step of the zinc beneficiation was initially characterized to investigate alternatives routes to obtain by-products from the gangues found in this tailing. The gangue of zinc tailing may contain dolomite, hematite, and impurities that are considered toxic elements, e.g. lead and cadmium. This work aimed to obtain MgSO4 and CaSO4 from real flotation tailing generated in zinc beneficiation. Thus, using physical processing, thermodynamic simulation (FactSage software), and hydrometallurgical route from dolomite. The following composition was identified in the characterization of zinc tailing by inductively coupled plasma optical emission spectrometry (ICP-OES): 7.96% Fe, 10.3% Mg, 17.4% Ca, 1.47% Si, 1.74% Zn, 0.2% Pb, 0.33% Al, 0.02% Cd, and 0.07% Mn. X-ray diffractometry (XRD) identified the phases of dolomite, hematite, and quartz. In the SEM-EDS analyses, it was possible to observe the disintegrated hematite, dolomite, and quartz particles, which allow the physical processing of these phases. Therefore, a dolomite concentration was investigated in the magnetic and gravity separation to eliminate mainly iron from the material understudy. The magnetic separation with the rougher cleaner route showed a better concentration of dolomite (90.3%) found in the non-magnetic fraction. The non-magnetic fraction was characterized by ICP-OES and presented a composition of 0.34% Al; 21.6% Ca; 0.04% Cd; 2.7% Fe; 11.9% Mg; 0.08% Mn; 0.2% Pb; 1.37% Si; and 1.73% Zn. Subsequently, a simulation was performed with the FactSage software to evaluate the leaching conditions varying the S:L ratio, the sulfuric acid concentration, and temperature were studied. Initially, pure dolomite was used in the simulation as a reference. Afterward, the composition was provided in the non-magnetic fraction of 90.3% and the other phases found in the zinc tailing were considered. The conditions for the pure dolomite were selected in 1.2mol.L-1 in a S:L ratio equal to 1:10, at room temperature showed 100% Mg extraction. Then, the simulation with 90.3% dolomite had 100% Mg extraction in 1.0mol.L-1 H2SO4 in a S:L ratio equal to 1:10 at room temperature. The leaching tests were performed using these conditions, varying the temperature in 25 - 50 - 75 and 90°C and the time from 5 to 180min, which a Mg and Ca extraction yield of 72% ± 5% and 2%, respectively, were obtained at 50°C in 35min. Using the cementation step, the purification method resulted in a 92.3% cadmium removal in the liquor from leaching with zinc powder in a 100:1 ratio in 5min at 25°C. The by-products obtained were MgSO4 and CaSO4, to be used in agriculture, magnesium sulfate (40% of MgSO4·7H2O for each 1kg) as a fertilizer (secondary macronutrient), and calcium sulfate as a soil conditioner (7.5% for each 1kg). O reaproveitamento de minerais a partir de rejeitos é fundamental para gerar menos impactos ao meio ambiente. A investigação de métodos que visam recuperar elementos que possam gerar subprodutos a partir de rejeitos de mineração vêm sendo estudada, como por exemplo, o rejeito do beneficiamento do zinco. O rejeito da etapa de flotação do beneficiamento do zinco foi caracterizado, inicialmente, para investigar novas rotas para obtenção de subprodutos a partir de gangas. A ganga do rejeito do zinco contém dolomita, hematita e impurezas, que são consideradas elementos tóxicos, ex.: chumbo e cádmio. O trabalho teve como objetivo a obtenção de sulfato de magnésio e sulfato de cálcio a partir do rejeito utilizando processamento físico, simulação termodinâmica (software FactSage) e rota hidrometalúrgica a partir da dolomita. Identificou-se na caracterização do rejeito de zinco, por espectrometria de emissão óptica por plasma acoplado indutivamente (ICP-OES) a seguinte composição: 7,96% Fe, 10,3% Mg, 17,4% Ca, 1,47% Si, 1,74% Zn, 0,2% Pb, 0,33% Al, 0,02% Cd, e 0,07% Mn. A difratometria de raios-X (DRX) identificou as fases de dolomita, hematita e quartzo. Nas análises realizadas no MEV-EDS foi possível visualizar as partículas desagregadas de hematita, dolomita e quartzo o que permitiu uma separação física dessas fases. Portanto, a concentração de dolomita foi investigada na separação magnética e gravítica para eliminar principalmente o ferro do material em estudo. A separação magnética rougher cleaner apresentou uma melhor concentração da dolomita encontrada na fração nãomagnética a qual foi caracterizada por ICP-OES e apresentou uma composição de 0,34% Al; 21,6% Ca; 0,04% Cd; 2,7% Fe; 11,9% Mg; 0,08% Mn; 0,2% Pb; 1,37% Si; e 1,73% Zn. Posteriormente, realizou-se uma simulação com o software FactSage para avaliar as melhores condições de lixiviação referente a relação S:L, variação da concentração de ácido sulfúrico e da temperatura. Inicialmente, utilizou-se na simulação, como referência, a dolomita pura e, em seguida, considerou-se a composição obtida na fração não-magnética (90,3%) e os demais elementos encontrados. As condições da dolomita pura foram selecionadas em 1,2mol.L-1, em uma relação S:L igual a 1:10, e temperatura a 25°C, obtendo-se uma extração de 100% do Mg na simulação. Em seguida, a simulação com 90,3% de dolomita obteve uma extração do Mg de 100% utilizando 1,0mol.L-1 de H2SO4 na relação S:L igual 1:10 a 25°C. Os ensaios de lixiviação foram realizados utilizando essas condições, variando-se a temperatura em 25 - 50 - 75 e 90°C e o tempo de 5 a 180min. Obteve-se um rendimento da extração de Mg de 72%± 5% a 50°C em 35min. Na etapa de purificação, utilizando o método de cementação, houve uma remoção do cádmio de 90,2% no licor da lixiviação com o pó de zinco numa relação de 100:1 em 5min a 25°C. Os subprodutos obtidos a partir da rota hidrometalúrgica foram MgSO4 e CaSO4, com o intuito de serem utilizados na agricultura, sendo o sulfato de magnésio (40% de MgSO4·7H2O para cada 1kg) como fertilizante (macronutriente secundário) e o sulfato de cálcio como condicionador do solo (7,5% para cada 1kg).

In this paper, three different processes—chelation accompanied by oxidation, oxidation followed by chelation, and oxidative acid leaching followed by chelation—are designed for extraction of zinc from oxide-sulphide zinc ore, and through a comparison of the redox potentials, suitable oxidation additives are determined for each process. Besides, effects of oxidant additives doping level on zinc recovery are investigated. The results show that the zinc leaching degree can reach 83.72% with addition of NaO being 0.3 mol/L in the process of chelation accompanied by oxidation, the zinc leaching degree can reach 92.40% with NaO adding 0.5 mol/L in the process of oxidation followed by chelation, and the zinc leaching degree can reach 93.02% under a condition of NaClO doping level being 0.1 mol/L in the process of oxidative acid leaching followed by chelation. All three processes prove their value on extraction of oxide-sulphide zinc ores.

Because zinc consumption rises and the high-grade zinc ore reserves decrease year by year, the secondary zinc resources have been paid close attention. The effect of sulfuric acid solution on the zinc recovery from industrial waste residue was studied in this paper. The results showed that under the conditions of sulfuric acid concentration of 0.61 M, liquid–solid ratio of 4:1, stirring speed of 400r/min, temperature of 25 °C, and leaching time of 30 min, the system had a relatively high zinc leaching rate, which reached 86.34%.

The study examined samples of soils and sediment (dumps) in areas exposed to the zinc ore enrichment of the Chaabet-al-Hamra deposit, by their color according to the Munsell color scale, determined the content of heavy metals and other elements, analysis of mercury, mineral composition, PH. It is shown that almost the entire studied territory, except for a small area in the foothills, has an excess of normative indicators for zinc, lead and cadmium. Copper contamination is less significant and is localized mainly on the territory of the plant itself.

The lead-zinc and polymetallic mineralization potential of Mongolia has been studied since the 1900s by joint Russian-Mongolian geological expeditions. Lead-zinc and associated metal deposits are mostly located in Eastern Mongolia, in relation to Mesozoic volcano-plutonic rocks. Geological survey in Mongolia has identified about 15 deposits and 120 occurrences in seven metallogenic belts. According to information by the Mineral Resources and Petroleum Authority of Mongolia, the current known lead resources of Mongolia are about two million tonnes. These include the Khar Tolgoi, Ulaan, Mungun-Undur, Tsav, and Dulaankhar Uul deposits. Since 2006, Mongolia started exporting polymetallic ore concentrate. By 2017, Mongolia exported 70,000 tonnes of zinc concentrate; however, this accounts for less than 1% of the world’s zinc exports. This export is from Tumurtiin Ovoo open pit mine in Eastern Mongolia, which produces annually 350–400 tonnes of zinc ore at 50% concentrate.

In this work, the dissolution properties of a dolomite containing zinc carbonate (smithsonite) oresample having 24.22% ZnO were determined in sodium hydroxide solutions using X-ray diffraction(XRD), Fourier-transform infrared spectroscopy (FT-IR), thermal (TG/DTA) and chemical analysesmethods. It was observed that the dissolution efficiency value of zinc continuously increased withthe increase of sodium hydroxide concentration from 1 to 4 M and the highest zinc dissolutionefficiency of 70.7% was reached after dissolution in 4 M NaOH solution at temperature of 298 K.The XRD, FT-IR, TG/DTA and chemical analyses of undissolved solids obtained after dissolutionof ore sample in 4 M NaOH solution at 298 K revealed that the smithsonite phase in the samplecompletely dissolved whereas the main gangue mineral dolomite remained practically unaffected,showing the selectivity of sodium hydroxide solution considering zinc dissolution. Although thesmithsonite phase in the sample totally dissolved, hundred percent zinc dissolution efficiencycould not be reached, which may indicate the presence of zinc in the gangue components, i.e.dolomite, clay minerals etc., of the studied ore sample., Bu çalışmada, dolomit içeren bir çinko karbonat (simitsonit) cevher numunesinin (%24,22 ZnO)sodyum hidroksit çözeltilerindeki çözünme özellikleri X-ışını kırınımı (XRD), Fourier dönüşümlükızılötesi spektroskopisi (FT-IR), ısıl (TG/DTA) ve kimyasal analiz yöntemleri kullanılarakbelirlenmiştir. Sodyum hidroksit derişiminin 1’den 4 M’ye artırılmasıyla çinko çözünme verimideğerinin sürekli olarak arttığı gözlenmiş ve %70,7’lik en yüksek çinko çözünme verimine 298K sıcaklıktaki 4 M NaOH çözeltisinde yapılan çözme işlemi sonrasında ulaşılmıştır. Cevhernumunesinin 298 K’deki 4 M NaOH çözeltisinde çözündürülmesi sonrasında elde edilençözünmemiş katıların XRD, FT-IR, TG/DTA ve kimyasal analizleri, numune içindeki simitsonitfazının tamamen çözündüğü halde ana gang minerali dolomitin büyük ölçüde çözünmeden kaldığınıortaya çıkarmakta, bu durum da çinko çözünmesi dikkate alındığında sodyum hidroksit çözeltisininseçiciliğini göstermektedir. Numunedeki simitsonit fazının tümünün çözünmesine rağmen yüzdeyüz çinko çözünme verimine ulaşılamaması, çalışılan cevher numunesi içinde bulunan dolomit, kilmineralleri vb. gibi gang bileşenlerindeki muhtemel çinko varlığını işaret etmektedir.

The flotation process is used to concentrate the zinc ore known as willemite. The process generates a residue consisted of hematite and dolomite. The residue used in this work presents desegregated hematite and dolomite particles, previously identified by MEV. In such a way, this work aims through gravity separation to concentrate the mineral phase hematite. The Wilfley shaking table was used to process 500 g of the tailing. Three different materials were obtained after the separation process: hematite concentrate, middling, and gravity separation tailing (GST). The characterization was carried out in SEM-EDS, XRD, and ICP-OES. SEM-EDS presented for concentrate, an iron content increasing from 7 to 44.5%. In concentrate, the XRD showed hematite peak intensity greater than the initial sample, different from other fractions. Analyses in ICP-OES showed that the concentrate material had 40.4% of iron, while in raw material, it was 7%. Therefore, gravity separation using Wilfley shaking table is seen as an interesting alternative since it reduces the zinc mine tailing, requires less energy and makes possible the material return to process in the steel industry.

In Viet Nam, non-sulfide zinc ore in the Cho Dien deposit has been exploited for a long time. Up to the present, zinc ore remains the major exploited ore in Cho Dien. There are numerous studies of Pb-Zn ore in Cho Dien. However, most of the studies have dedicated only to description of mineralogical and chemical composition of Pb-Zn ore. There has been no publication on this non-sulfide zinc ore. Based on the mineralogical studies, the content of Pb and Zn in groundwater determined by reflective microscope, SEM, EPMA and ICP-MS methods, the study explained the formation of secondary non-sulfide zinc ore in the Cho Dien deposit. Strong weathering process makes the upper part of ore bodies completely oxidized. Difference in geochemical behavior of lead (Pb) and zinc (Zn) in the oxidation process of Pb-Zn ore is the reason to form non-sulfide zinc ore in the Cho Dien deposit. Oxidation of primary Pb-Zn ore is mainly sphalerite, pyrite, galena minerals which creates a low pH environment and transforms of zinc from immobile (sphalerite - ZnS) to mobile (Zn2+) and retained in solution under acid pH conditions whereas lead has the tendency to form soluble minerals (anglesite, cerussite). The acid neutralization actions of the surrounding rocks make zinc precipitate, to form secondary non-sulfide zinc minerals.ReferencesAndreas Nuspl, 2009. Genesis of nonsulfide zinc deposits and their future utilization (www.geo.tu-frei berg.de/oberseminar/OS_09/Andreas_Nuspl.pdf.Boland M.B., et al., 2003. The Shaimerden supergene zinc deposit, Kazakhstan: Economic Geology, 98(4), 787-795.Chau N.D., Jadwiga P., Adam P., D.V. Hao, L.K. Phon, J. Paweł, 2017. General characteristics of rare earth and radioactive elements in Dong Pao deposit, Lai Chau, Vietnam, Vietnam J. Earth Sci., 39(1), 14-26.Dao Thai Bac, 2012. 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Society for geology applied to mineral deposits (SGA) News, Number 15. https://www.e-sga.org/fileadmin/sga/newsletter/news15/art01.html.McPhail D.C., et al., 2003, The geochemistry and mobility of zinc in the regolith: in Roach, I.C., ed., Advances in Regolith, 287-291.Murray W. Hitzman, et al., 2003. Classification, genesis, and exploration guides for non-sulfide zinc deposits: Economic Geology, 98(4), 685-714.Nguyen V.P., 2013. Wet tropical wethering in Viet Nam. Natural Science and Technology Publisher.Nicola Mondillo, 2013. Supergene Nonsulfide Zinc-Lead Deposits: The Examples of Jabali (Yemen) and Yanque (Peru). Doctoral thesis.Nordstrom D.K., Alpers C.N., 1999. Geochemistry of acid mine waste. Review in Economic Geology, the environmental geochemistry of ore deposits/Eds. G.S.Plumlee, M.J. Logsdon. Part A: Processes, techniques, and health issues, 6A, 133-160.Reynolds N.A., et al., 2003. The Padaeng Supergene Nonsulfide Zinc Deposit, Mae Sod, Thailand. Economic Geology, 98(4), 773-785.Sangameshwar S.R., Barnes H.L., 1983. Supergene Processes in Zinc-Lead-Silver Sulfide Ores in Carbonates: Economic Geology, 78, 1379-1397.Stumm W., Morgan J.J., 1996. Aquatic Chemistry, Third Edition. John Wiley & Sons, New York, NY.Takahashi T., 1960. Supergene alteration of zinc and lead deposits in limestone: Economic Geology, 55, 1083-1115.Thornber M.R. and Taylor G.F., 1992. The mechanisms of sulphide oxidation and gossan formation, in: Butt, C.R.M., and Zeegers H., (Eds.)., Regolith exploration geochemistry in tropical and subtropical terrains, in Govett G.J.S., ed., Handbook of exploration geochemistry: Amsterdam, Elsevier, 4, 119-138.Tran Trong Hoa, 2005. Potential assessment of By- products in lead-zinc and copper deposits of Northeast Vietnam. Final report.Tran Tuan Anh, 2010. Studying accompanying component in the types of potential deposits of basic metals and precious - rare metals of north Viet Nam to improve the efficiency of mining and environmental protection. Final report. KC.08.24/06-10.Tran Tuan Anh, et al., 2011. Mineralogical and geochemical characteristics and forming conditions of lead - zinc deposits in Lo Gam structure, northern Vietnam. J. Sci. of the Earth, 33(3DB), 393-408 ( in Vietnamese).Vito Coppola et al., 2009. Nonsulfide zinc deposits in the Silesia - Cracow district, Southern Poland. Springer Link, 44, 559-580.Vito Coppola, et al., 2007. Non-sulfide zinc deposits in Upper Silesia, Southern Poland. Proceeding of the Ninth Biennial SGA Meeting, Dublin, 1401-1404.Williams P.A., 1990. Oxide zone geochemistry: Ellis Horwood Ltd., Chichester, UK, 286p.

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

Photocatalysis is an advanced oxidation process that can degrade and mineralize organic pollutants in wastewater to carbon dioxide and water which was employed in this study. Tannery effluent was treated via batch photoreduction using Zinc oxide photocatalyst supported on y-Al2O3 and irradiated under visible light at the ambient condition of temperature. Zinc oxide obtained from Zinc ore and y-Al2O3 prepared from local kaolin were used to synthesize the ZnO/y-Al2O3. The synthesized photocatalyst was characterized by Brunnaer Emmett Teller (BET), X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscope (SEM), and X-ray Fluorescence (XRF). The result of the analysis reveals that the total surface area, total pore volume and mean pore size of the photocatalyst prepared were 65.452 m2g-1, 0.151 cm3g-1 and 9.892 nm respectively. The photocatalyst is crystalline and the SEM image shows the presence of pores. The ZnO/y-Al2O3 was used as a photocatalyst to reduce Chromium (VI) of a typical tannery wastewater. 96% reduction of 20 mg/L of Cr (VI) was achieved at 60 min, pH of 3, and a photocatalyst dosage of 2.5 g/L under visible light of 400 W intensity. The kinetic study revealed that the photoreduction was fitted into the pseudo-first-order Lagmuir-Hinshelwood kinetic model. This research demonstrated that ZnO/y-Al2O3 photocatalyst was effective in the photoreduction of the selected response for the treatment of tannery wastewater.

International audience; The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran. They include the Mehdiabad, Irankouh and Angouran world-class deposits, as well as the Zarigan and Haft-har deposits. These deposits were formed by supergene oxidation of primary sulfide minerals during the complex interplay of tectonic uplift, karst development, changes in the level of the water table, and weathering. Zn (Pb) carbonates, Zn-hydrosilicates and associated hydrated phases directly replace the primary ore bodies or fill cavities along fractures related to uplift tectonics. Direct replacement of primary sulfides is accompanied by distal precipitation of zinc non-sulfide minerals in cavities or internal sediments filling. The mineralogy of the non-sulfide mineralization in all six deposits is generally complex and consists of smithsonite, hydrozincite, and hemimorphite as the main economic minerals, accompanied by iron and manganese oxy-hydroxides and residual clays. Commonly, non-sulfide minerals in these deposits consist of two types of ore: red zinc ore (RZO), rich in Zn, Fe, Pb-(As) and white zinc ore (WZO), typically with very high zinc grades but low concentrations of iron and lead. Typical minerals of the RZO are Fe-oxyhydroxides, goethite, hematite, hemimorphite, smithsonite and/or hydrozincite and cerussite. Common minerals of the WZO are smithsonite or hydrozincite and only minor amounts of Fe-oxyhydroxides and hemimorphite. Ó 2017, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

In this study, a new flotation approach, a low-alkaline and non-desliming process, was introduced for improving lead and zinc recoveries, lowering production cost and reducing environmental pollution. Lab-scale experiments results show that the new process contributed to the flotation of the complex mixed sulfide-oxide lead and zinc ore regarding two aspects: (1) High alkaline process (pH = 12±) was replaced by low alkaline process (pH = 9±) by using collector WS (a mixture of ethyl thiocarbamate, ammonium dibutyldithiophosphate and dithiophosphate-25) and combined depressant Na2S/ZnSO4/Na2SO3 for lead sulfide flotation; (2) Non-desliming process was successfully achieved by using collector MA (a mixture of ether amine, hydroxyethyl cellulose and polyacrylic acid) and combined depressant SHP/SS (sodium hexametaphosphate/sodium silicate) for zinc oxide flotation. And 43.37% Pb in the Pb concentrate was recovered, the corresponding Pb grade was 52.73%, total 84.42% Zn was recovered by the flotation of zinc sulfide minerals and zinc oxide minerals. Moreover, the two aspects of the new approach were systematically verified from lab-scale to industrial-scale application. The industrial-scale flotation tests show that Pb recovery in Pb concentrate increased by 1.86% compared with that of original system during industrial-scale tests period, and the Pb recovery increased by 4.09% compared with that of original system before industrial-scale tests period, while the Zn operating recovery in zinc oxide concentrate improved by 19.52%. Moreover, the total reagent cost of the whole new process significantly declined by 3.93 yuan per ton of ore.

In our study, a detailed survey was conducted with the aim to determine the distribution and possible anthropogenic sources of molybdenum in river and stream sediments in the central Upper Silesian Industrial Region (Southern Poland), where for many years, iron and zinc smelters as well as coking and thermal power plants were operating. At the same time, this has also been a residential area with the highest population density in the country. Sediments (1397 samples in total) were collected from rivers and streams, and analysed for the content of molybdenum and 22 other elements. ICP-AES and CV-AAS methods were applied for the determination of the content of elements. The studies revealed molybdenum content in the range of < 0.5–204.8 mg·kg−1with the average content 1.9 mg·kg−1. About half of the samples contained < 0.5 mg·kg−1of molybdenum, and only 4.6% of the samples showed values > 5 mg·kg−1. The spatial distribution of molybdenum demonstrated by the geochemical map has indicated that the principal factor determining its content in sediments is the discharge of wastewater from steelworks and their slag heaps. Another source of this element in sediments has been the waste of the historical mining of zinc ore and metallurgy of this metal. Additionally, molybdenum migration from landfills of power plants, coal combustion and Mo emission to the atmosphere and dust fall-out have been significant inputs of Mo pollution to the sediments.

Life cycle assessment was carried out via ReCiPe H method to evaluate environmental impact of the hydrometallurgical zinc production chain in China. National statistical data and process-based life cycle inventory (LCI) were used to build a zinc production LCI at the macro level. To confirm the credibility of this study, an uncertainty analysis was conducted via Monte-Carlo simulation. The impacts of climate change, human toxicity, marine ecotoxicity, freshwater ecotoxicity, metal depletion, and fossil depletion categories on the overall environmental burden were examined. The overall environmental burden was dominated by key processes, such as zinc ore mining and energy (i.e., electricity and natural gas) consumption. In 2013, the amounts of carbon dioxide, sulfur dioxide, nitrogen oxide, particulate matter, zinc, and copper generated by hydrometallurgical zinc production were 2.60 × 10 7 , 4.29 × 10 4 , 6.77 × 10 4 , 1.23 × 10 4 , 1.38 × 10 3 , and 3.20 × 10 2 t. The first four substances accounted for 0.25%, 0.21%, 0.30%, and 0.10% of the overall national emission. Effective approaches to reduce the overall environmental impact of hydrometallurgical zinc production include improving the efficiencies of electricity, natural gas, and zinc ore consumption; substituting clean energy for coal-based electricity production; reducing the direct emission of zinc and copper; and increasing the national zinc recycle rate.

The Vazante deposit, which is the world's largest zinc silicate deposit, occurs in brecciated dolomite and comprises mainly willemite with various proportions of hematite, Fe-carbonate, minor franklinite and magnetite. Exploration for this type of deposit is more challenging than zinc sulfide deposits, as they do not exhibit similar geophysical anomalies. To improve the application of geophysical surveys to the exploration of hypogene silicate zinc deposits, data from 475 samples were investigated from drill holes representative of the various types of ore and host rocks as well as barren zones of known geophysical anomalies in the Vazante District. Lithogeochemical and mineralogical (optical, SEM and MLA) data were integrated with physical rock properties (density, magnetic susceptibility and K U Th gamma-ray spectrometry) to assist in exploring for this type of deposit. The most distinct physical property of the ore is density, compared with the host rocks due to high proportion of denser minerals (hematite and willemite). However, barren hematite breccias also have high densities. The zinc ore and hematite breccias yielded higher magnetic susceptibilities than the surrounding host rocks, with the highest values associated with greater proportions of franklinite and magnetite. The density and magnetic susceptibility contrasts are a result of hydrothermal fluids interacting with and altering the carbonate host rocks. Zinc ore also yielded elevated U concentrations relative to the various host rocks, yielding higher gamma-ray spectrometric values. The results of this investigation indicate that an integration of magnetic, gravimetric and radiometric surveys would be required to identify zinc silicate ore zones.

Pre-concentration consists of the preliminary discarding of a fraction of the mineral processing plant feed which contains little or none of the mineral of interest, reducing the mass to be processed in downstream operations (e.g. milling, concentration and dewatering), as well as the capital and operational costs. In this context, this study investigates the performance of density and sensor-based sorting separation methods in the removal of carbonate gangue of a zinc ore, in size fractions typical of crusher products, using sink and float tests with heavy liquids, jig stratification and laboratory scale ore sorting tests using an X-Ray Transmission (XRT) sensor. The best results were obtained through sink and float in heavy liquids, which indicated the possibility of discarding 30% of the feed mass, removing over 60% of the carbonates (CaO and MgO) and losing only 2% of the zinc. The ore sorting tests also presented positive results, with approximately 93% of metallurgical recovery in 70% of the mass for both size fractions tested. The jig stratification results were worse, since the zinc content discarded with this method was high. The results indicate significant reduction potential for Capex and Opex costs using pre-concentration strategy.

In this paper, a novel combination of phase transformation and leaching is proposed to recover zinc from an oxide–sulphide zinc ore. Accordingly, various analytical technologies, such as X-ray diffraction, chemical analysis, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, are employed. The phase transformation of a raw ore and the effects of microwave heating and Na2O2 addition on zinc leaching are investigated. The results show that the addition of a strong oxide Na2O2 can directly transform the refractory phases, particularly zinc sulphide, into zinc sulphate. As a result, SO2 emissions are avoided and an environmentally friendly zinc recovery process is realised. Both microwave heating and the Na2O2 level have significant effects on phase transformation and zinc leaching. The zinc leaching rate can reach 82.06% under the following conditions of microwave heating: adding Na2O2 at a mass ratio of 25%, leaching in an ammonium chloride solution with a total ammonium concentration of 7.5 mol/L and an ammonia/ammonium chloride molar ratio of 1:1, adding NaClO as an aid-leaching reagent and leaching for 1 h. By contrast, the zinc leaching degree for the ore samples roasted in a traditional electric resistant furnace is only 30.62%. Moreover, at the same oxidation degree, the total energy consumption by the proposed process is 0.78 kWh/(kg·ore), which is lower than that by traditional heating (same power). Thus, the combination technology of microwave-heated phase transformation and leaching is effective in treating oxide–sulphide zinc ore.

The object studied is Shaimerden oxidized zinc ore deposit containing zinc, lead, copper, iron, calcium, magnesium, aluminum, manganese and silicon. Chemical and mineralogical composition of the ore are investigated. It is established that ore coarse fraction contains more zinc carbonate and less zinc silicate compared with undersize particles. In addition, ore coarse fraction is richer in residual forms (nontronite, sphalerite) hardly soluble in sulphuric acid solution. Thermodynamic analysis of probable transformations during leaching is carried out, kinetics of coarse fraction and undersize particles of ore leaching is studied, and Pourbaix diagrams are plotted for analysis of processes occurring at a phase interface during leaching of oxidized zinc ore. Studies for stripping oxidized zinc ore are carried out on large (–20+1 mm) and small (–1+0 mm) fractions. Optimum leaching parameters are established for fine and coarse ore fractions: sulfuric acid concentration and process temperature and duration (C(H2SO4) = 150–160 g/liter, temperature 60°C, leaching time 60 min). Dependences are determined for the degree of zinc extraction into solution on sulphuric acid concentration, temperature, and leaching duration for coarse and fine ore factions.

The constantly increasing global demand of zinc metal along with the decreasing zinc ore reserves has led to an upward trend of zinc production from secondary sources. Galvanizing industry generates byproducts and wastes containing zinc in the form of intermetallic compounds or oxides (zinc dust). One such byproduct, waste pickling liquor (WPL) is generated in galvanizing industry during the pickling of defective galvanized material. WPL contains Zn and Fe in ionic form and is discarded after neutralization. In the present work, chemical precipitation method is used to recover zinc from WPL; with an objective to retain maximum possible iron within the WPL solution. The effect of precipitating agent concentration, number of reactions steps, temperature and stirring speed were considered to determine process parameters for maximum zinc recovery. The iron rich WPL solution with negligible quantities of zinc is a valuable ingredient for production of red oxide pigment. Thereby, two products are obtained by adopting this technique: (i) Zinc rich precipitates and (ii) iron rich pickling liquor. X-ray diffraction (XRD) analysis of precipitates (heated at elevated temperature), shows that zinc oxide and zinc ferrite phases were formed from the zinc rich precipitates.

Cementation is a prominent purification technique used for removal of copper, cadmium, cobalt, and nickel from impure zinc sulphate solution obtained after leaching of zinc ore. Zinc dust is primarily used for this purpose still the extent of purification is limited. The present study represents the encouraging result in context to utilization of zinc dust for better purification by altering its dosage, size and morphology. The investigations showed that 300% excess zinc dust dosage than stoichiometric results in enhanced cement formation. The study also revealed that fine size and ball milling of zinc dust favors cementation. Zinc dust of −300 mesh (BSS) after 2 h ball milling highly purifies the impure solution within 2 h contact time. The yield of the impurities removal after the optimized cementation is 100, 99.99, 100 and 15% for Cu, Cd, Ni and Co respectively. The kinetics of cementation has been also studied and revealed that the reaction is in mixed controlled mechanism for copper and cadmium cementation. At the same time, for nickel, it is considered to be chemically controlled. The activation energy for the cementation of copper, cadmium and nickel were 38.19, 30.87 and 68.15 kJ /mol, respectively. The estimated activation energies were found within the range which corroborates with the mixed and reaction model and ensures industrial feasibility of the proposed process.

Composite materials with polymers and waste materials like zinc ore, mill scale, ironwork dust are studied with respect to attenuation of electromagnetic radiation of high frequency. Samples of such composites were prepared and tested for several frequencies in X band (S-12 GHz). The composites relatively strongly attenuate electromagnetic radiation in the considered band. They could be used as material for cases of various devices that are sensitive for electromagnetic radiation. Using various waste materials has also ecological aspect.

The Proterozoic Vazante zinc silicate district in Minas Gerais, Brazil, hosts world-class hypogene willemite deposits in dolomitic rocks interbedded with siliciclastic rocks deposited in subtidal to supratidal environments. Willemite ore bodies are structurally controlled along regional NE-trending structures which are interpreted as being active during the Neoproterozoic Brasiliano orogeny. The hydrothermal alteration is characterized by an early stage of Fe-dolomite, which replaced the host dolomitic rocks, followed by precipitation of minor sphalerite and then hematite and willemite. Elements commonly enriched in the zinc ore include As, Ba, Be, Bi, Cd, Co, Fe, Ge, In, Mo, Ni, Sb, Se, U, V and W. Mineralogical, fluid inclusion and isotopic data indicates that mixing of S-poor metalliferous saline fluids with meteoric water favored the formation of willemite ore. Carbonaceous phyllites from the underlying thick siliciclastic sequence show evidence of early enrichment in zinc (and ore-related metals) and remobilization, respectively, prior to and during the Brasiliano orogenic event. This unit is interpreted as a possible source of ore-related elements. It is proposed that during the Brasiliano orogeny, hot (T > 170 °C) saline fluids (>15 wt % eq. NaCl) leached metals from siliciclastic source rocks and precipitated willemite ore in the overlying dolomitic sequence along structures that favored mixing with oxidizing meteoric water.

The pilot-scale production of cathode zinc from low-grade zinc oxide ore through periodic extraction in NH3–NH4Cl–H2O system was studied. Leachant balance in circulation process was controlled by parameters of recycling rate (γ) and relative concentration error (De) between CMeLn and CMeL∞ according to the equation . The concentration of zinc in leach liquor was enriched in 39·085 g/L after five recirculation leaching cycles, which was consistent with the predicted value theoretically when recycling rate was supposed to 0·467.Cathode product containing more than 99·9% of Zn and current efficiency of 97·02% were obtained after purification of two-stage treatment. The liquid loss was confirmed to exist in electrowinning operation and the problem of solution balance was solved through partial diverging cycle and addition of washing water in residue washing unit. Mineralogical analysis results showed that about 90% of ammonia-soluble Zn (ZnCO3 + ZnSO4) dissolved out from zinc ore.

The article describes the geological structure of the Amur stratiform zinc deposit, including ore-bearing flysch and overlying volcanic strata, the position of the sulfide ore body in geological section. Given the fact that a large part of the main ore body lies among carbonaceous deposits, in the latter by means of thermal analysis was estimated the degree of metamorphic change with the introduction of large Suunduk granite massif, as well as the study of content in them tungsten. Rare metal specialty of granite was previously proved by works of many researchers. We found that the ore-bearing carbonaceous shales contain industrial concentration of tungsten. In some cases they reach hurricane levels (up to 2200 g/t). However, analysis of the results of studies of black shale formation showed a high content of tungsten only in the eastern, closest to Suunduk massif, part of the geological allotment, but west of the boundary of the amphibolite and greenschist metamorphism facies, that we have identified according to thermal analysis. This allowed us to identify the promising area within which an attempt was made to estimate inferred resources of tungsten by category P 2 . The main parameters for calculation of resources are the average content of metal in carbonaceous deposits and the average thickness of the ore zones, which were calculated on the basis of data sturry and furrow samples. The result is a medium-scale object with resources of about 5 thousand tons of tungsten. It is known that zinc ore of Amur deposit currently classified as off balance ore, uneconomical to develop. However, given the estimated inferred resources of such an important associated metal such as tungsten in ore-bearing carbonaceous shales, the field may be attributed to the group of complex and ore to balance.

Dating of lead-zinc deposits is of critical importance for better understanding of ore genesis, but has long been a big challenge due to the lack of suitable minerals that can be unequivocally linked to the ore genesis and that can be used for tradition radiometric methods. This kind of deposits have simple mineralogy dominated by galena and sphalerite commonly associated with calcite and other gangue minerals. Both galena and sphalerite have low and high variable Re concentrations and thus Re-Os dating of these minerals have been less promising. In addition, the recovery of Re is extremely low for galena when conventional method was applied, lending additional difficulty in precisely dating galena. In this study, we investigate the recovery of Re using different media for anion exchange separation and reporte a revised preparation method for Re-Os dating of galena and sphalerite. By using the new protocol, two reliable Re-Os isochron ages of galena and sphalerite from the Fule (20.4±3.2 Ma) and Laochang (308±25 Ma) Pb-Zn deposits in Yunnan Province, SW China, are achieved.

This study investigates an unusual source of environmental lead contamination - the emission and deposition of lead and zinc concentrates along train lines into and out of Australia's oldest silver-lead-zinc mine at Broken Hill, Australia. Transport of lead and zinc ore concentrates from the Broken Hill mines has occurred for more than 125 years, during which time the majority was moved in uncovered rail wagons. A significant amount of ore was lost to the adjoining environments, resulting in soil immediately adjacent to train lines elevated with concentrations of lead (695 mg kg(-1)) and zinc (2230 mg kg(-1)). Concentrations of lead and zinc decreased away from the train line and also with depth shown in soil profiles. Lead isotopic compositions demonstrated the soil lead contained Broken Hill ore in increasing percentages closer to the train line, with up to 97% apportioned to the mined Broken Hill ore body. SEM examination showed ceiling dusts collected from houses along the train line were composed of unweathered galena particles, characteristic of the concentrate transported in the rail wagons. The loss of ore from the uncovered wagons has significantly extended the environmental footprint of contamination from local mining operations over an area extending hundreds of kilometres along each of the three train lines.

In this article, the role of MnO2 in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO2 during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO2 will produce an aggregation of ZnMn2O4, a valuable energy material, while roasting on its own, results in generating undesirable Zn2SiO4, the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO2, which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO2 effectively avoids, thus MnO2 deems as a potential additive in the recovery of oxide-sulphide zinc ore.

This article is devoted to theoretical investigations into the thermodynamic simulation of a zincoligonite ore (Zhairem deposite, Kazakhstan)-carbon systems in the temperature ranges from 1000 to 3000 K and pressure range from 0.001 to 0.1 MPa using the Astra bundled software based on the entropy maximum principle. It is revealed that an increase in the amount of deoxidizer in the charge results in a decrease in the degree of conversion of silicon to elemental Si because of an increase in its conversion to carbides. The lower deoxidizer content results in an increase in the silicon fraction converted to SiO at the practically complete absence of reduced elemental Si. When reducing pressure in the system from 0.1 to 0.001 MPa, temperatures for the complete conversion of zinc (1500–1200 K) and lead (1900–1500 K) and for the beginning of silicon formation (2300–1900 K) decrease. The noticeable (>50%) formation of elemental Si at P = 0.001 MPa can be attained at T ≈ 2450 K.

Stemming from an examination of the zinc industry in early modern China, this article centers on a detailed survey of coal, the primary source of energy for processing zinc. On the basis of Qing archival documents, this article investigates the previously unknown spatial relationship of zinc ore deposits, coal mines, and zinc smelters; provides quantitative evidence of coal use by estimating the annual consumption of coal in processing zinc; offers a new perspective on the general use of coal in Qing China; and compares the coal-fuel efficiency problem in early European and Chinese zinc production.

In a VMS ore at Al Amar gold mine (level 640 FW-E), sulfide minerals are paragenetically ordered as follows: pyrite(I)–sphalerite–chalcopyrite–galena–pyrite(II), deformations vary from brittle to ductile deformation fabrics. Microscopically, the massive sulfides have pyrite porphyoblasts (up to ∼80%) that show evidence of creep dislocation as a result of low-temperature plastic deformation rather than brittle failure, whereas high-temperature annealment is completely lacking. Softer minerals such as chalcopyrite fill into fractures in pyrite as narrow slivers. Needle-shaped or lamellar morphology of chalcopyrite, together with the chemical composition of Fe-poor sphalerite (with maximum 0.99 wt% Fe) suggest a combined replacement–coprecipitation mechanism of chalcopyrite disease formation rather than an exsolution texture. Greenschist facies metamorphism produces an ore with distinct chalcopyrite disease into a stratified ore with microbands of chalcopyrite and sphalerite. Ore microfabrics and uncommon occurrence of epithermal stringers suggest noticeable effect of the Najd tectonics in the studied level. The EMPA analyses indicate that all sulfide minerals in the VMS ore are auriferous and the Au contents are considerable (up to 0.94, 1.31, 0.16 and 1.20 wt%; in sphalerite, chalcopyrite, galena and pyrite, respectively). Gold in pyrite is “invisible” whereas it occurs as submicroscopic inclusions in sphalerite, chalcopyrite and galena. The VMS ore of Al Amar deep horizons are characterized by the occurrence of “invisible gold”, Ag-free galena, Fe- and Ni-poor sphalerite, negligible hydrothermal alteration, plastic deformation of pyrite and non-exsolution origin of the chalcopyrite disease intergrowth which are together strong indicators of low-temperature (250–300 °C).

In recent years, recovering zinc from low grade oxidized zinc ore has been a matter of discussion. In this paper, the investigation for recovering zinc and iron from gossan ores was carried out. In generally, the conventional physical separation methods, such as flotation, gravity separation and magnetic separation, were used to treat the low grade ore, and flotation is the most commonly used method for beneficiation and pretreatment of oxidized zinc minerals. However, gravity separation and magnetic separation are used to deal with the gossan ores because of the special zinc oxide ore bearing iron 40.2% in this study. The effects of grinding fineness and magnetic intensity were investigated, respectively. The results show that the grade of zinc and iron increase slightly, and the best result is that the grade of zinc and iron are 13.35% and 40.25%, the recovery of zinc and iron are 53.45% and 52.19%.

This study was conducted to build up the inventories of Pb isotopic compositions of major Pb pollution sources in South Korea. Since non-ferrous metal smelters are one of major anthropogenic sources, two smelters for zinc, each one of smelter for lead and copper were selected for the study. The Pb concentrations and isotopic compositions of metal ores, wastewater, sludge, metal rod and produced sulfuric acid were analysed to understand the Pb isotopic patterns in environment. The isotopic ratio, , of zinc ores from zinc smelter were in the range of 1.179~1.198 and the ratio of waste, flue gas and products samples were 1.105~1.147. This results implied that the isotopic patterns of output samples showed mixing patterns between two distinct metal ore soerces. In 2011, major importing countries of zinc ore were Australia, Peru and Mexico. Thus Pb isotopic patterns from zinc smelter is originated from the mixing patterns between less radiogenic Australian ores and more radiogenic South America`s ores. Lead smelters also showed the same mixing patterns with those of zinc smelters. However copper smelter showed same Pb isotopic patterns with more radiogenic South America`s ores.

The unusually high grade hypogene zinc ore at Angouran in northwestern Iran (40.4% Zn, 1.9% Pb in the sulfide ore, 28.1% Zn, 4.4% Pb in the carbonate ore, and 110 g/t Ag) formed from an initially highly saline, reduced, relatively acid hydrothermal brine at two successive sulfide and carbonate ore stages. The early ore stage consists of multiple phases of sphalerite dominated sulfide ore breccia with subordinate amounts of galena (± Pb sulfosalts), minor pyrite, and abundant barite. Sphalerite precipitated at moderate temperatures (≥ 155 °C) because of pH increase in the presence of hangingwall marble. Smithsonite precipitated at a higher pH value (≥ 7) and at lower temperatures (≤ 120 °C) from dilute solutions (salinities close to zero) by mixing of the Zn bearing brines with cool, HCO 3 − bearing waters. The first melting points of the primary (LV) fluid inclusions in sphalerite and in hydrothermal quartz are unusually low (≤ − 60 °C), close to the eutectic point of the ZnCl 2 –H 2 O system (− 62 °C). Total salinities taken from the ZnCl 2 –H 2 O system as a best approximation correspond to 26–41 eq mass % ZnCl 2 . The initial brine evolved to a CaCl 2 –NaCl rich solution with 27 eq mass % salinity. Gas densities (≤ 0.1 g cm − 3 for water vapor and ≤ 0.18 g cm − 3 for CO 2 ) in the fluid inclusions indicate low pressure (≤ 5 bar for water vapor, and ≤ 100 bar for CO 2 ) at the entrapment temperatures. At the first carbonate ore stage sulfides continued to precipitate characteristically as arsenopyrite with minor amounts of galena and pyrite. The abrupt change of the fluid composition at the sulfide–carbonate boundary was accompanied by a change of the fluid temperature and pressure that produced brecciation of the sulfide ore matrix and an almost total dissolution of barite and replacement by the hypogene smithsonite. Alteration is restricted to ore deposition and consists of weak sericitization and silicification with local dolomitization at the sulfide ore stage, and pervasive dissolution of the hangingwall marble, in particular at the carbonate ore stage. The breccia orebody at Angouran is sited at the crestal portion of a domed antiform at the lithological and thrust boundary of Neoproterozoic–Lower Cambrian footwall schists and the hangingwall marble in rapidly uplifted and exhumated Angouran Block east of the Geynardjeh Thrust Fault. The footwall schists occupy a detachment fault zone above imbricated nappe sheets of the basement metamorphic complex of the Sanandaj–Sirjan zone. During the Pliocene, the nappe sheets were thrust toward the southwest onto the Miocene felsic volcanic rocks of the Urumieh Dokhtar Volcanic Belt that are intruded by 10 Ma late Miocene basalts. The 11.9 Ma and 18.4 Ma zircon ages of the felsic volcanic rocks indicate the lower age limit of the ore body emplacement. The associations with large scale, mid-late Miocene, felsic volcanism along the active Tethyan belt, as well as the ubiquitous presence of the volcanic rock clasts in the sphalerite ore matrix, provide strong evidence of the involvement of hydrothermal processes at Angouran. Ore fluids were successively and pulsatorily generated within the seismically active region. A following geothermal activity appears to have had a significant input in the formation of the carbonate ore of the hypogene, as well as the supergene stage. Stable isotope data suggest complex interaction of element sources and processes. Allowing a broad interpretation, the sulfur isotopic composition of the sulfides δ 34 S (3.9 to 7.4‰) suggests that the sulfur could be sourced from evolving, mixed magmatic–basinal brine. The isotopic composition of the hypogene smithsonites (δ 13 C: 2.72 to 5.51‰, δ 18 O: 18.4 to 22.8‰) broadly supports the local geology and field relationships, which comply with a marble wallrock source for the carbonate ores. They lend support to the assumption that smithsonite was deposited from solutions with isotopic composition similar to those involved in the hydrothermal dolomitization of the marbles. The excess of dissolved marble precipitated as large volumes of travertine and as late calcite veins (δ 13 C: 18.8 to 20.3‰, δ 18 O: 3.1 to 6.4‰) at the mineralization site. Isotope values of the travertine (δ 13 C: 4.5 to 6.6‰, δ 18 O: 20.1 to 21.1‰ V-SMOW) are consistent with the involvement of CO 2 derived from thermogenic decarbonization of the host marble by waters of dominantly meteoric origin, most likely concomitantly with ore forming processes. The Angouran deposit is the only reported case of a two stage, hypogene zinc sulfide–zinc carbonate mineralization, and represents a new style of nonsulfide zinc mineralization.

Leaching test on the Oxidized Zinc Ore coming from Yunnan Province is studied in the H2SO4 system;Systematic studies are made to show the effects of various factors on the leaching rate of zinc. The optimum conditions for leaching is finally confirmed, namely the grinding size is 75% of-0.074mm, concentration of sulfuric acid 15%, temperature 60°C, solid to liquid ratio 3:1, and leaching time 2.5h. Ultimately, the leaching rate of Zn could reach more than 59%.

Polymetallic sulfide ores (Zn, Pb, Fe, Cu, Ag, and Cd) found in the Alanish locality of northern Iraq are hosted by dolostone in the Late Permian Chia Zairi Formation. The Alanish locality is one of several Zn–Pb deposits that are widespread in northern Iraq, situated along the northern passive margin of the Arabian plate. This paper describes the ore deposit classification, mineral chemistry, and paragenetic sequence of the area and proposes an ore formation model. We report the presence of acanthite and greenockite for the first time in Iraq. A brine solution derived from the sedimentary basin formed the primary sulfide ore minerals (sphalerite, galena, acanthite, pyrite, chalcopyrite, greenockite, and marcasite). The pre-tectonic mineralization is characterized by replacement textures including (1) high-Fe, low-Zn, dark-colored, coarse-grained sphalerite; (2) deformed anisotropic coarse-grained galena; and, (3) idiomorphic cubes of crushed pyrite. Conversely, the post-tectonic mineralization is characterized by open-space filling textures, including (1) low-Fe, high-Zn, light-colored, fine aggregated sphalerite; (2) fine-grained galena; and, (3) the existence of acanthite and marcasite. Although galena is an Ag carrier, both mineralization phases contained non-argentiferous galena. Non-sulfides (smithsonite, cerussite, and goethite) have replaced older sulfides in many areas due to supergene process. Gangue minerals present are dolomite, calcite, barite, and siderite. Open spaces and cavity filling of small paleo-karsts, replacement, veins, and veinlets are common features of the ore body. Metals were sourced from brines generated in the sedimentary basin, whereas sulfur was derived from nearby evaporates. Sediment compaction and tectonic activity, probably during Late Cretaceous, were the driving forces that squeezed and moved ore-bearing fluids derived from the sedimentary basin. Multiple stages of ore-bearing fluids were epigenetically intruded into the Late Paleozoic dolostone, forming an epigenetic strata-bound Mississippi Valley-type deposit precipitated under a temperature of 120 °C, as indicated by the cadmium fractionation in sphalerite and galena. Dolomitization and tectonic activity provided the necessary permeability for accumulating ores. The main ore body is directly connected to a fault plane and to adjacent dolostone that is frequently fractured and brecciated.

The filtration problems on acid leaching sludge of high silicon zinc ore have been paid extensive attention in zinc hydrometallurgy. It was found that soluble silica can be effectively converted into silica precipitate with good settling, filtration and washing properties, and the filtration rate can be in excess of 800 L/m2 · h under certain leaching conditions. According to investigating on the filtration rate, viscosity and concentration of silica of leaching sludge or liquor, the filtering temperature can tremendously improve the filtration property of pulp. At the same time, the experimental data indicated that the viscosity of leaching liquor was the key factor influencing filtration property of leaching sludge.

Jarosite is a leach residue that can be produced by industrial bulk metal treatment processes and typically has the chemical formula Mx Fe3 (SO4 )2 (OH)6 , where M normally represents a metal cation. The largest source of jarosite is electrolytic zinc processing [1], which worldwide has an annual production of 11-12 Mt and an associated jarosite waste of 5-6 Mt that can cause important challenges due to its classification as a problem waste. Moreover, as zinc ore typically contains many other commercial/critical metals, the content of valuable materials in this material is significant. An analysis of jarosite from Kokkola, Finland shows that it contained as much metal as many present day commercial ores: ~15% iron, 2% zinc, 3 % lead, 150 g/t silver, 0.5 g/t gold, 100 g/t indium and 40 g/t gallium. Until now, jarosite related research has concentrated on its use in landfill and construction purposes [2], though there is increasing interest in finding methods to efficiently reprocess/recycle jarosite into valuable products [3, 4]. The hydrometallurgical process currently under development by VTT and Aalto University exploits jarosite powdery nature to undertake wet chemical processing. This low cost and energy efficient operation is targeted at the recovery of concentrates which contain the major value-added metals.

Streszczenie Występowanie złóż rud cynku i ołowiu w skałach dolomitowych sprawia, że otrzymane koncentraty sfa-lerytowe zawierają domieszkę dolomitu. Praktyka wskazuje, że znaczna część wprowadzanego magnezu z su­rowcami cynkowymi przechodzi do ostatniej fazy produkcji, elektrolizy cynku. Obecność magnezu w elektrolicie obniża przewodnictwo elektryczne elektrolitu i powoduje pogorszenie wskaźników techniczno-ekonomicznych. Celem opisanych w tym artykule badań było opracowanie metody usuwania magnezu z surowego koncentratu sfalerytowego na drodze chemiczno-flotacyjnej, stosując zużyty elektrolit pochodzący z elektrolizy cynku. Opracowanie ukierunkowano wokół doświadczalnego zobrazowania istniejących zależności i ustalenia opty­malnych warunków zaproponowanej procedury. Stopień wyługowania magnezu wynosił około 80%. Straty cynku wynosiły poniżej 2%, natomiast stężenie magnezu w roztworze wynosiło 20%. Z tych roztworów można odzys­kiwać magnez i cynk, co będzie przedstawione w następnej publikacji.

The catalytic-oxidative leaching of a mixed ore, which consists of low-grade oxide copper ore and oxide zinc ore containing ZnS, was investigated in ammonia-ammonium sulfate solution. The effect of the main parameters, such as mass ratio of copper ore to zinc ore, liquid-to-solid ratio, concentration of lixivant, leaching time, and temperature, was studied. The optimal leaching conditions with a maximum extraction of Cu 92.6 pct and Zn 85.5 pct were determined as follows: the mass ratio of copper ore to zinc ore 4/10 g/g, temperature 323.15 K (50 °C), leaching time 6 hours, stirring speed 500 r/min, liquid-to-solid ratio 3.6/1 cm3/g, concentration of lixivant including ammonia 2.0 mol/dm3, ammonium sulfate 1.0 mol/dm3, and ammonium persulfate 0.3 mol/dm3. It was found that ZnS in the oxide zinc ore could be extracted with Cu(II) ion, which was produced from copper ore and was used as the catalyst in the presence of ammonium persulfate.

The flotation performance of a complex lead and zinc ore were investigated by changing the grinding environments. Four groups of testing were conducted with different depressants or their combinations. Flotation results, size-by-size analysis, pulp potential (Eh) and dissolved oxygen (D0) were studied. It was found that the addition of depressants during grinding was beneficial to increasing the separation efficiency.

Natural resources such as ores contain radioactive nuclides at various concentrations. Therefore it is important to investigate the radioactivity in these resources as well as in the soil at the locations of ore deposits. For that reason we conducted preliminary measurements in the soil samples taken from the locations of lead and zinc ore deposits in Bosilegrad and Raška and from the locations of phosphate ore deposits in Bosilegrad to estimate the environmental conditions prior to the ore excavation. The activity concentrations of radionuclides in soil, water and plant samples were determined by gamma spectrometry (HPGe detector, relative efficiency 23%). Results showed the presence of natural radionuclides (226)Ra, (232)Th, (40)K, (235)U, (238)U as well as the produced radionuclide (137)Cs (from the Chernobyl accident). Ambient gamma radiation dose rate in ground level air was also measured. In order to estimate the influence of subsequent mining on the working and living environment, radium equivalent (Ra(eq)), external hazard index (H(ex)), external gamma absorbed dose rate ([Formula: see text]) and annual effective dose (D(E)) were determined.