Search

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 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.

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.

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 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.

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.

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 processing mineralogy characteristics of an oxidized lead-zinc ore from Sichuan were studied systematically using numerous modern instruments. Results showed that lead and zinc oxide content in the ore exceeded the minimum industrial grade, and also included a relatively high concentration of silver and iron. This ore is composed of many different minerals. Major zinc-containing minerals include sphalerite, hemimorphite, smithsonite, hydrozincite, zinc-containing baileychlore, and zinc-containing dolomite and calcite. Lead-containing minerals are primarily galena and cerussite with small amounts of dechenite, cesaronite, anglesite, limonite and coronadite. Gangue minerals include dolomite and calcite. Dissemination size for the main minerals ranges from medium (0.04 mm) to fine (0.02 mm). All the valuable minerals are well liberated, including galena, sphalerite, cerussite, calamine, and smithsonite. However, the dissemination relationships are complex. Lead is concentrated mainly in galena and cerussite, while zinc occurs primarily in sphalerite, calamine, and smithsonite. The theoretical recovery for lead and zinc were estimated at 72% and 67%, respectively.

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.

Lead-Zinc mineralization in some parts of Izzi area has attracted a number of private miners into the area. The miners can not be said to have been very successful. This is due to the nature of mineralization which occur in isolated vein-lodes that are fracture controlled. Their information on the mineralization or prospecting has been based on reports of Villagers, Shallow hand-dug pits and of douncing rod exercise. Results of 30 electric Self Potential (SP) measurements at two prospective zones of the locality has positive responses for Sulphide mineralization indicated by high negative SP anomaly along two separate bands. The trend of anomaly shows prospective zones of mineralization in the North-South axis across the area, with dip direction towards the North, following the trend of the shale host rock and along the two prospective bands. Result of seven Vertical Electric Soundings (VES) show that the overburden material to the shale host rock consisting of Sandy-Siltstone and Shaly-Mudstone has average depth between 25-39m, given thickness of 11-19m across the area. The Shale host rock is classified into three layer-zones based on resistivity value. A non mineralized zone, with resistivity value less than 3000 (ohm-m). A mineralized zone with resistivity value between 3000 to 5000 (ohm-m) where sphelarite (Zinc ore) is predominant and a highly mineralized zone with resistivity value between 6000 to 8000 (ohm-m) where Galena (lead ore) is dominant. The two bands are due to faulting . Band A at the down throw portion of the fault corresponds to the topographically low area and Band B at the upthrown, corresponds to high topography zone of the study area. KEY WORDS: Fault-fractures, Vein-lodes, Dip, Contours, Resistivity, Geo-Electric Section, Anomaly and Mineralization Potential. Global Jnl Geological Sciences . Vol.2(1) 2004: 61-66

Low molecular weight polyacrylamide (PAM) polymers were used to separate copper-activated sphalerite from pyrite in the presence of isobutyl xanthate (IBX). The effects of carboxyl, sulfonate, hydroxyl or thiourea functional groups attached to the polymers on the flotation recoveries of sphalerite and pyrite were studied as a function of polymer concentration and order of reagent addition. It was found that all the PAMs depressed pyrite flotation with no or little depression of sphalerite. The following order for pyrite depression was obtained: hydroxy>carboxyl≥thiourea>sulfonate, and for mineral selectivity: carboxyl≥sulfonate>hydroxy≫thiourea. It was also found that a greater mineral depression was obtained for the coarser particles and when the PAMs were added before the collector.

The application of SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA) is reported for analysis of huge Raman image data of dust samples collected in the vicinity of lead and zinc smelters. The Raman data were carried out using Raman microprobe and automated mapping stage at 1 μm step size over at most 80 μm ×70 μm sample area for each experiment. Numerous significant pure spectra were extracted by the SIMPLISMA method. Results provide the number of major as well as minor chemical species. Concentration maps of the resolved components demonstrate the heterogeneity of individual particles at level of 1 μm spatial resolution. A discussion is given addressing the analysis aspects of SIMPLISMA and the relative merits and drawbacks of the technique in comparison with conventional analysis from two real Raman image data.

Three methods of improving zinc concentrate grade in the flotation of two massive sulphide ores were investigated. These methods involve the use of oxygen gas conditioning, copper specific collectors or selective polymeric depressants. The results obtained demonstrated that all three methods provide high zinc concentrate grades through depression of iron sulphide minerals. It was also found that by combining two methods, reagent consumption could be decreased without decreasing overall performance.