Zinc Production Research Articles

Global strategic level supply planning of materials critical to clean energy technologies – A case study on indium

Many clean energy technologies depend on some rare materials, and significant concerns about the sufficient supply of these materials have been raised recently. Most of the rare materials are so called by-product materials, and thus their supplies heavily rely on the demand of base metals. This study develops a generic mixed integer linear programming to investigate global strategic level capacity and production planning for both base and by-product materials. Other decisions relevant to capacity expansions and productions are also considered. The model is demonstrated using indium as a case study. Indium is a key material needed by two emerging clean energy applications, copper indium gallium selenide photovoltaics and light-emitting diode lighting. Supply of indium exclusively depends on primary zinc production, and concerns have been raised on whether there will be sufficient supply to support widespread applications of these two technologies. Capacity expansions of indium refinery facilities can be the first solution to overcome its supply risk. All the decisions included in the model are numerically analyzed. Sensitivity of all the parameters to the total cost are also studied. Indium content in the ore, inflation rates, and discount rates are found to have significant impact on the total cost.

Heavy metals contamination and human health risk assessment in soils of an industrial area, Bandar Abbas – South Central Iran

ABSTRACTThe purpose of this study was to determine the contamination level, distribution, health risk and potential sources of Cr, Cd, Pb, Zn, Cu, Ni and As in 66 topsoil samples from industrial areas in Bandar Abbas County. The geoaccumulation index, pollution index and pollution load index were calculated to assess the pollution level in the industrial soils. The hazard index and carcinogenic risk were used to assess human health risk of heavy metals. Results showed that the contamination levels of heavy metals were in the descending order of Cu> Cd> Pb> Zn> As> Ni> Cr. Moreover, based on principal component analysis, Cd, Zn, Cu, and Pb originated mainly from anthropogenic sources, including power plants, oil and gas refinery, steel and zinc production factories and municipal waste landfills. For non-carcinogenic effects, hazard index of studied metals decreased in the order of Cr> As> Cd> Pb> Ni > Cu> Zn. Arsenic, chromium and cadmium were regarded as the priority pollutants. Carcinogenic risks due to Cd and As in suburban soils were within tolerable risk to human health; however, children faced more health risk in their daily life than adults via their unconscious ingestion and dermal contact pathway.

Characterization of cast iron and slag produced by jarosite sludges reduction via Arc Transferred Plasma (ATP) reactor

Jarosite process is the most widely adopted method for zinc production via a hydro-metallurgical route. Jarosite sludges are classified as hazardous waste by the European Waste Catalogue. Up to now, jarosite sludges were stored in lined pounds within the zinc refinery, representing a pollutant source for subsurface and groundwater. Landfilling is possible only after a stabilization treatment that covers twice the amount of waste to be disposed of. In this paper, a new method to recover the residual iron content within jarosite sludges through an Arc Transferred Plasma (ATP) reactor is presented. Reduction of jarosite sludge leads to the production of cast iron, accompanied by the formation of a glassy inert slag that can be easily disposed of in inert waste landfills, or better, recovered as alternative to stone materials. This process results in the recovery of the whole amount of jarosite sludges, reducing to zero the waste to be disposed of.

Assessment of spatial distribution pattern of heavy metals surrounding a lead and zinc production plant in Zanjan Province, Iran

The present study aimed at characterizing the spatial distributions and investigating the contents of six heavy metals (Co, Ni, Cu, Zn, Cd and Pb) in top soils, surrounding the National Iranian Lead and Zinc Company (NILZ) in Bonab Industrial Estate (Zanjan-Iran) by Geostatistical analyst and Moran's I autocorrelation index. The soil samples (126) were collected from the area with a radius of 5km of the NILZ Company. The average amount of Co, Ni, Cu, Zn, Cd and Pb metals were 4.16mgkg−1, 26.38mgkg−1, 18.31mgkg−1, 684.11mgkg−1, 5.79mgkg−1, and 119.59mgkg−1, respectively. Principal Components Analysis (PCA) classified the investigated heavy metals in two groups. These groups were Factor I (Pb and Cu) and Factor II (Co, Ni, Zn and Cd) that confirm exist the anthropogenic source of the pollutants. Moran's I autocorrelation index was cleared that the high–high spatial clusters of topsoils contaminated with heavy metal were located in the center of study area, near NILZ Company. It was deduced that the company activities have a big impact on distribution of heavy metal in study area. Geostatistical analysis revealed that the high values of all studied heavy metals were located near the NILZ Company. According to comparison the prepared and land use maps, it was cleared that pesticides and chemical fertilizers, geochemistry and anthropogenic sources are the main factors in spatial variation of heavy metals.

Solar chemical looping gasification of biomass with the ZnO/Zn redox system for syngas and zinc production in a continuously-fed solar reactor

The high-temperature solar-driven chemical looping gasification of lignocellulosic biomass with ZnO/Zn redox pair was investigated as a novel process producing both syngas and metallic zinc. A lab-scale solar reactor (1.5 kW) was operated for continuous combined biomass gasification and ZnO carbo-thermal reduction using solar energy as the source of high-temperature process heat. Experiments were performed at temperatures ranging from 1050 °C to 1300 °C with biomass/ZnO molar ratios from 0.5 to 1, using beech wood as a biomass feedstock. The objective of this study was to unveil the advantages and reliability of the combined process involving biomass pyro-gasification with solid ZnO as an oxidizing agent under continuous process operation for co-production of syngas and metallic Zn. The influence of temperature and reactant molar ratio on syngas production was highlighted and compared to the case of a pyrolysis process without any oxidant. Moreover, the chemical conversion of ZnO to Zn obtained by this endothermic step was also addressed, confirming pure Zn production with low recombination in the collected solid products. The evolved H2 increased significantly, CO production also tended to increase slightly, while CO2 and CH4 decreased when increasing the temperature. The syngas yield of the combined gasification/carbo-thermal reduction (up to ∼8 molsyngas/molbiomass for a biomass/ZnO molar ratio of 0.75 at 1250 °C) was much higher in comparison with pyrolysis. The calorific value of the feedstock was solar up-graded through syngas and Zn production in the case of the biomass gasification using ZnO, whereas pyrolysis was not energetically efficient because of the energy content still remaining in the produced char. The optimal biomass/ZnO molar ratio was evidenced at 0.75 yielding maximum syngas production. The energy upgrade factor of the feedstock by the solar power input and the solar-to-fuel energy conversion efficiency were 1.17 and 19.8% respectively for a molar ratio of 0.75 at 1250 °C.

Sonochemical synthesis and characterization of new seven coordinated zinc, cadmium and mercury nitrate complexes: New precursors for nanostructure metal oxides

The nitrate complexes of group 12 elements with a tridentate Schiff base ligand (L = (E)-N1-((E)-3- phenylallylidene)-N2-(2-((E)-((E)-3-phenylallylidene) amino)ethyl) ethane-1,2-diamine) were synthesized via sonochemical process and characterized by various physical and chemical methods. The structural analysis of the zinc nitrate complex by single crystal X-ray diffraction analysis shows that the central atom is seven-coordinated by three nitrogen atoms from the Schiff base ligand as well as four oxygen atoms from two different nitrate anions. The geometry around the metal center can be described as a distorted pentagonal bipyramid. The crystal packing analysis of zinc nitrate complex indicates that the intermolecular interactions related to nitrate groups plays the essential role in the orientation of supramolecular structure. Hirshfeld surfaces (HS) and their corresponding fingerprint plots (FP) have been also used for further investigation of crystal structure of zinc nitrate complex. Furthermore thermal analyses (TG/DTG) of three nanostructure complexes were carried out and discussed. Finally, direct thermolysis of zinc and cadmium nitrate complexes in air atmosphere led to the production of zinc and cadmium oxide nanoparticles.

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues (ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals (mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L−1, a liquid/solid ratio of 4:1 (mL/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L−1, a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.

Development of a combined solid and liquid wastes treatment integrated into a high purity ZnO hydrometallurgical production process from Waelz oxide

Electric Arc Furnace Dust (EAFD) is an important hazardous waste from the steel production industry, due to its heavy metals content. It is recycled through a pyrometallurgical process to generate a Zn and Pb concentrate called Waelz oxide. This concentrate can be processed hydrometallurgically in order to obtain high purity ZnO. But this hydrometallurgical process also generates as wastes different solid residues with high content of heavy metals and a liquid waste stream with significant concentrations of ammonia and heavy metals. This is why the objective of this work is to design a process that can simultaneously treat these solid and liquid wastes. In the developed process, an alkaline solution is used to leach solid residues so as to produce an inert final waste. After filtration, the leaching liquor is mixed with the liquid waste in order to increase its pH and to enhance the ammonia evaporation by air stripping. This stripped stream can be recycled to the leaching stage of the Waelz oxide treatment process. Furthermore, the ammonia stripping precipitates the dissolved heavy metals as a zinc concentrate that can be commercialized as a raw material for the metallic zinc production industry. Therefore, the developed process reduces by more than half the wastes generation, increases the Zn recycling yield >5% and recovers >75% of the needed ammonia for the fresh leaching liquor.

Sorption Removal of Fluorine Ions, Incoming with the Recycling Zinc-Bearing Materials

<p>The possibility of using inorganic sorbent, iron oxyhydrate (IOH) to remove F<sup>-</sup> ions from technological solutions of zinc production is considered in this article. The principal possibility of the use of ion-exchange resins as carriers modified by IOH is considered. The formation of the active substance on cation-exchange resins was studied. It was shown that the most durable composite sorbents were obtained using strong-acid cation-exchange resins with SO<sup>3-</sup>- groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The strong acid cation exchanger KU-2×8 is recommended as the basis of the composite. </p>

Investigation of Viscose Rayon Manufacturing Sludges, Considered as a Raw Material for Zinc Production

<p>At treatment of wastewater of viscose rayon’s spinning produces the sediment – zinc-bearing sludge, a humidity content of 66 to 95 %. To date, it is deposited up to 2.5 million cubic meters of zinc-bearing sludge in the ponds of plants in Russia. In the paper chemical composition and particle size distribution of sludge of viscose rayon manufacturing (OJSC “Balakovskoye khimvolokno”, OJSC “Ryazanskoye khimvolokno”, OJSC “Sibvolokno”) are presented. The percentage of zinc in sludge is of 6 to 23 %. Investigations by methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) are shown, that zinc is present in form of hydroxides, carbonates and silicates. Thermodynamic analysis of zinc dissolution of compounds, found in product of sludge roasting at a temperature of 850ºС, was conducted.</p>

Physiological performance of wheat seeds treated with micronutrients and protection products during storage

Abstract: Seeds with high quality are one of the important factors to consider in the crops establishment on field. Therefore, the physical and physiological quality of wheat seeds treated with mixes of micronutrients including zinc and protective products were aimed. The wheat seeds were analyzed in a factorial scheme 5x3x4, with five storage time: 0, 60, 120, 180 and 240 days; three micronutrients: micronutrients 1 (1% Mn; 0.1% Mo; 10% Zn); micronutrients 2 (0.3% B; 0.3% Co; 3% Zn) and no micronutrients, and four protective products: untreated seeds, polymer (Colorseed He), fungicide carboxin + thiram (Vitavax® Thiram 200 SC) + insecticide thiamethoxam (Cruiser® 350 FS) and polymer + fungicide + insecticide. After treatment, the seeds were stored under uncontrolled conditions for 240 days and at intervals of 60 days, the germination, accelerated aging and moisture content were determined. Wheat seeds untreated and treated with polymer have the best physiological performance during storage, regardless micronutrients treatments. The wheat seeds treated with carboxin + thiram + thiamethoxam and polymer + carboxin + thiram + thiamethoxam can be storage up to 120 days, under uncontrolled conditions, regardless micronutrients treatments. The seed treatment does not alter the moisture content of wheat seeds.

Investigation of zinc extraction from different leach residues by acid leaching

With different properties, zinc is one of the most important non-ferrous metals and it is used in various application areas, especially as an anti-corrosion agent. In Turkey, zinc production was based on zinc carbonate ores (ZnCO3), at Cinkur plant from establishment to 1997 due to high reserves of zinc carbonate. After that, zinc concentrate coming from Iran was used in this plant over the last two decades. Thus, two different leach residues called as Turkish leach residue (TLR) and Iranian leach residue (ILR) were accumulated more than one million ton in Cinkur stock piles. In this study, it is aimed to investigate zinc recovery for each leach residue by use of sulphuric acid (H2SO4) and to compare the TLR and the ILR. Initially, detailed chemical, mineralogical and thermal analyses of these different leach residues were carried out. In order to investigate the effect of acid concentration and reaction duration on zinc recovery, leaching experiments were carried out at following conditions: 95 °C, 100 g/L pulp density and 600 rpm stirring rate. According to the characterization results, the chemical compositions for both residues are nearly similar; however, experimental results show that zinc recovery per cent of the ILR was higher than that of TLR for all experimental durations and acid concentrations. This may be due to the presence of Zn-containing compounds in the both residues at different percentages.

Sorption kinetics of indium, iron, and zinc ions on modified montmorillonite

Adsorption integral kinetic curves of indium and iron(III) ions were obtained from model solutions on a montmorillonite Metosol modified with di(2-ethylhexyl)phosphoric acid. The adsorption kinetics can be reliably described with pseudofirst and pseudosecond order models. Adsorption of metal ions on a Metosol reagent occurs in a mixed diffusion mode. The rate constants of external and internal diffusion on the Metosol reagent are greater for In3+ ions than those for Fe3+ one, so that it can be used for the selective sorption of indium from complex technological solutions in zinc production.

Sorption technology of recovery of indium from solutions of zinc production

Sorption of indium ions from polycomponent solutions with preliminarily reduced iron(III), which contain, g/dm3, 0.084 In3+, 6.2 Fe2+, 67.0 Zn2+, and 19.6 H2SO4, on the Metosol reagent, is investigated in the dynamic mode. The Metosol reagent represents montmorillonite of composition (Na,Ca)0.3(Al,Mg)2Si4O10(OH)2(H2O) n , modified with di(2-ethylhexyl)phosphoric acid. The absorption dynamics of ions by it is investigated by frontal chromatography. The values of working (DEC) and total (CDEC) dynamic exchange capacities of the mineral sorbent are determined depending on the eluent specific passing rate and temperature. The main parameters of the sorption technology of the selective recovery of indium from process solutions of the zinc production on the Metosol reagent in columns followed by the desorption of metal with the hydrochloric acid solution (1: 1) are substantiated and calculated.

Life cycle assessment of the hydrometallurgical zinc production chain in China

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 × 107, 4.29 × 104, 6.77 × 104, 1.23 × 104, 1.38 × 103, and 3.20 × 102 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.

Parameters optimization and kinetics of direct atmospheric leaching of Angouran sphalerite

In this research, a zinc sulfide (sphalerite) concentrate of Angouran mine was studied by direct atmospheric leaching process. This process is an alternative to the conventional method of roast-leach-electrowinning (RLE) for zinc production by assisting ferric ions as powerful oxidant. The independent sphalerite leaching parameters investigated were ferric ions concentration (0.4–1.2M), temperature (40–80°C), particle size (21–53μm), sulfuric acid concentration (0.5–1.5M) and time (2–6h). Response surface methodology (RSM) was used to optimize the process parameters. The most influencing parameter was found to be temperature and the less effective was acid concentration. Based on the results, ferric ions illustrate a complex effect on the recovery of zinc; In this regard, interaction of ferric ions with operational parameters was proposed. The optimum recovery for leaching of the zinc sulfide concentrate (e.g., 84.72%) was obtained at ferric ions concentration of 1.2 M, temperature of 80°C, mean particle size of 21μm and leaching time of 6h. The predicted percentage recovery of zinc at the optimum condition was found to be 84.96% which was very close to the experimental value of 84.72%. Kinetic investigation was carried out in the optimum condition that obtained by RSM. Kinetic results showed that there were two stages in the sphalerite leaching. At the beginning of the leaching process, kinetics of sphalerite leaching is fast, while after about an hour the overall rate of leaching has decreased. The kinetic of leaching in the first stage is affected by both rate of chemical reaction and rate of diffusion through the sulfur layer. In this stage, the contribution of chemical reaction gradually decreases by increasing the temperature. In the second stage, the leaching rate of sphalerite is controlled only by diffusion through the product layer.

Evaluating the Effectiveness of Push-Pull Ventilation System for Controlling Lead, Zinc and Sulfuric Acid Emitted from Zinc Electrolysis Units of a Zinc Production Industry

Evaluating the effectiveness of push-pull ventilation system for controlling lead, zinc and sulfuric acid emitted from Zinc electrolysis vans of a zinc production industry

Sorption technology of indium extraction from zinc production solutions

The article studies the dynamic sorption of indium ions from polycomponent solutions with pre-reduced iron (III) containing, g/dm3: 0,084 In3+, 6,2 Fe2+, 67,0 Zn2+ and 19,6 H2SO4, on the Metosol reagent. The latter is a montmorillonite with the following composition (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2(H2O)n, modified by di(2-ethylhexyl) phosphoric acid. Its absorption dynamics of metal ions was studied by the method of frontal chromatography. The article determines the values of working (DEC) and total (TDEC) dynamic exchange capacities of the mineral sorbent depending on the specific throughput rate and the eluent temperature. The article justifies and calculates the basic parameters of the sorption technology of selective indium extraction from process solutions used for zinc production operations on the Metosol reagent in columns with subsequent desorption of metal by hydrochloric acid solution (1 : 1).

Perfection Of Methods Of Mathematical Analysis For Increasing The Completeness Of Subsoil Development

The economy of Russia is based around the mineral-raw material complex to the highest degree. The mining industry is a prioritized and important area. Given the high competitiveness of businesses in this sector, increasing the efficiency of completed work and manufactured products will become a central issue. Improvement of planning and management in this sector should be based on multivariant study and the optimization of planning decisions, the appraisal of their immediate and long-term results, taking the dynamic of economic development into account. All of this requires the use of economic mathematic models and methodsApplying an economic-mathematic model to determine optimal ore mine production capacity, we receive a figure of 4,712,000 tons. The production capacity of the Uchalinsky ore mine is 1560 thousand tons, and the Uzelginsky ore mine - 3650 thousand. Conducting a corresponding analysis of the production of OAO “Uchalinsky Gok”, an optimal production plan was received: the optimal production of copper - 77961,4 rubles; the optimal production of zinc - 17975.66 rubles. The residual production volume of the two main ore mines of OAO “UGOK” is 160 million tons of ore.

USE OF ZINC ASH FROM GALVANIZATION AS A SOURCE OF ZINC OXIDE

This paper reports the possibility of using zinc ash as a secondary source for zinc oxide, which can be further used as white pigment. For the extraction of zinc from zinc ash, sulphuric acid was used. The impact of different parameters (ash fraction, contact time, sulphuric acid concentration and liquid:solid (L:S) ratio) upon the extraction degree of metallic ions from zinc ash was studied. The optimum conditions for the metallic ions extraction are: 20 % H2SO4, 30 minutes contact time, 1:1 L:S ratio and the fraction of the ash <0.315 mm. The obtained solid zinc products were submitted to a complex study: chemical analysis, thermal analysis and X-ray diffractometry. It was established that from the resulting zinc ash from the hot-dip galvanizing process the zinc ions can be recovered and reused as useful products avoiding the negative impact of these wastes on the environment and at the same time it was shown that these wastes represent valuable zinc sources. Based on the experimental data, the non-polluting technological process scheme of reuse of zinc ashes in useful products was proposed.