The Preliminary Investigation of Low Grade Zinc Oxide Ore

Flotation is a conventional way for treating low grade metal oxide ore which has some advantages such as high efficiency and low cost. In order to recover the zinc from a low grade complex zinc oxide ore in which the grade of Zn is 13 wt.%, this paper presents a preliminary investigation of this type of ore by flotation method. In the experiments, the effects of different parameters such as grinding fineness, amount of Na2SiO3, amount of Na2S and amount of octadecylamine were investigated in relation to the metal contents of concentrates. The results show that about 35% of initial Zn content was obtained with 70% -200 mesh grinding fineness, 1000g/t Na2SiO3, 2000g/t Na2S and 500g/t octadecylamine. It is clear that the preliminary flotation tests with the ore sample indicated that there was no selectivity in terms of zinc recovery. Almost 65% zinc remained in the tailings and could not be recovered by flotation due to its complicated mineralogical structure. Therefore, application of metallurgical processes is proposed for zinc recovery from the tailings in the following investigations.

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Alkaline Leaching of Low Grade Complex Zinc Oxide Ore

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.158.12 ◽

2010 ◽

Vol 158 ◽

pp. 12-17 ◽

Cited By ~ 5

Author(s):

Shao Jian Ma ◽

Jin Lin Yang ◽

Gui Fang Wang ◽

Wei Mo ◽

Xiu Juan Su

Keyword(s):

Zinc Oxide ◽

Metal Oxide ◽

Ammonium Chloride ◽

Ammonium Carbonate ◽

Preliminary Investigation ◽

Low Grade ◽

Leaching Rate ◽

Alkaline Leaching ◽

Solid Ratio ◽

Zn Content

Alkaline leaching is an important way for treating low grade metal oxide ore, which has some advantages such as low corrosion and low pollution compared to acidic leaching. In order to recover the zinc from a low grade complex zinc oxide ore in which the grade of Zn and Fe are 13 wt.% and 40.2 wt.%, respectively, and 52.8% of Zn is contained in siderite, 34.63% in limonite and 11.55% in smithsonite, this paper presents a preliminary investigation of this type of ore by alkaline leaching method. In this study, ammonia-ammonium chloride and ammonia-ammonium carbonate were used as the leaching reagents. The effects of alkaline concentration, leaching time, leaching temperature and liquid to solid ratio (L/S) were studied, respectively. The results show that 43.15% of initial Zn content was extracted adopting ammonia-ammonium chloride as the leaching reagent in 4.5M at 30°C for 3h with a liquid to solid ratio of 4:1, while 43.07% of Zn recovery was achieved employing ammonia-ammonium carbonate as the leaching reagent at 5M, 30°C and 4:1(L/S). The low leaching rate of Zn is probably attributed to that the zinc contained in siderite was not extracted completely because Zn and Fe exist as isomorphism in siderite.

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Impact of Pre-Desliming on Flotation of Low-Grade Zinc Oxide Ore from Lanping

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.3385 ◽

2013 ◽

Vol 634-638 ◽

pp. 3385-3389

Author(s):

Wen Juan Zhao ◽

Dian Wen Liu ◽

Xiao Lin Zhang ◽

Shu Qin Zeng ◽

Guo Yin Xu ◽

...

Keyword(s):

Zinc Oxide ◽

Economic Benefit ◽

Low Grade ◽

Zinc Recovery ◽

Calcium And Magnesium ◽

Flotation Performance ◽

The Impact

Zinc oxide ore from Lanping contained large amount of fine slime which badly deteriorated flotation performance, and it complexly intergrowed with plenty of alkaline gangues with calcium and magnesium. In order to investigate the impact of pre-desliming on flotation, experiments of direct flotation and pre-desliming flotation were carried out in the work. Finally, a zinc recovery of 88.73% with a Zn grade of 13.93% was obtained in direct flotation test, and a higher zinc recovery of 95.25% with a Zn grade of 13.56% was achieved by pre-desliming flotation. Pre-desliming flotation test was superior to direct flotation test, because of an increase of nearly 7% in zinc recovery under the condition of similar Zn grade. At the same time, dosage of sulfurization agent used in pre-desliming flotation was lower by 46.67% than that in direct flotation, which obviously improved the availability of sulfurization agent. So both product index and economic benefit were enhanced after pre-desliming.

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Removal of Heavy Metals (Lead, Cadmium and Iron) from Low-Grade Nanoscale Zinc Oxide Using Ammonium Carbonate Solution as a Leaching Agent

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.778.132 ◽

2018 ◽

Vol 778 ◽

pp. 132-136

Author(s):

Muhammad Yasir Khan ◽

Ali Dad Chandio ◽

Muhammad Sohail ◽

Syed Zeeshan Abbas ◽

Rao Shakeel Ahmed ◽

...

Keyword(s):

Zinc Oxide ◽

Ammonium Carbonate ◽

Low Cost ◽

Polymer Nanocomposite ◽

Device Fabrication ◽

Carbonate Solution ◽

Low Grade ◽

Axis Orientation ◽

Lead And Cadmium ◽

Removal Of Heavy Metals

This study investigated the purification and refining method for producing a nanometer size zinc oxide (ZnO) from the low-grade ZnO commercial powder using low cost ammonium carbonate solution as a leaching agent. The atomic absorption spectroscopy results show that the concentration of iron, lead and cadmium can be dramatically reduced by ammonium carbonate leaching and washing. X-ray diffraction (XRD) and scanning electron microscope (SEM) results show that structural properties can improve the degree of the preferential c-axis orientation, grain size, and surface morphology of ZnO by solvent evaporation. All physical and chemical results are of particular significance for the preparation of purified ZnO for device fabrication in photovoltaic industry, functional ZnO coatings, and polymer nanocomposite applications.

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Removal of Ethyl Orange Dye Using Hybrid Chitosan and Zinc Oxide

Jurnal Teknologi ◽

10.11113/jt.v67.1665 ◽

2014 ◽

Vol 67 (1) ◽

Cited By ~ 1

Author(s):

Norzita Ngadi ◽

Mohamad Akmal Mahmud ◽

Mazura Jusoh ◽

Roshanida Abd Rahman ◽

Hajar Alias

Keyword(s):

Zinc Oxide ◽

Azo Dye ◽

Large Scale ◽

High Efficiency ◽

Low Cost ◽

Mixing Time ◽

Freundlich Isotherm ◽

Water Soluble ◽

Scale Production ◽

Mixing Rate

Ethyl Orange is a type of water-soluble azo dye, which is widely used in the textile, printing, paper manufacturing, pharmaceutical and food industries. Due to a large-scale production and extensive application of azo dyes, it can cause considerable amount of polluted wastewater and can generate serious health-risk factors. Chitosan, a low cost adsorbent has been widely used to treat azo dye. Recent studies had discovered heterogeneous photocatalysis using semiconductors such as zinc oxide is quite applicable because of its ability to decolorize dye-containing wastewater more effectively. The purpose of this research is to hybridize the low-cost adsorbent chitosan and semiconductor zinc oxide to produce an adsorbent which has high efficiency for removing azo dye. The parameters that were used in this study are pH values (pH 5.0 to 9.0), temperature (25 to 60◦C) and the initial dye concentration (0.10 to 1.00 mg/L). The results obtained showed that hybrid chitosan and zinc oxide adsorbent had successfully decolorized ethyl orange dye in water. The optimum conditions for the highest removal of ethyl orange (85%) were achieved at following conditions; temperature of 60°C, using adsorbent containing 1 g of chitosan and 2.0wt % of zinc oxide, 1.0 mg/L of dye concentration, at pH 7 and 2 hours of mixing time with 130 rpm of mixing rate. In this study, the adsorption process was found to fit the Freundlich isotherm than of the Langmuir isotherm.

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Synthesis and Performance Evaluation of Chitosan/zinc Oxide Nanocomposite as a Highly Efficient Adsorbent in the Removal of Reactive Red 198 From Water

10.21203/rs.3.rs-915379/v1 ◽

2021 ◽

Author(s):

Najmeh Amirmahani ◽

Hakimeh Mahdizadeh ◽

Neda Seyedi ◽

Alireza Nasiri ◽

Ghazal Yazdanpanah

Keyword(s):

Zinc Oxide ◽

Adsorption Capacity ◽

High Efficiency ◽

Low Cost ◽

Industrial Effluents ◽

Textile Wastewater ◽

Secondary Compounds ◽

High Adsorption ◽

Reactive Red 198 ◽

High Adsorption Capacity

Abstract Disposal of textile industrial effluents causes many environmental problems. The presence of chemical dyes in textile wastewater lead to the primary environmental pollution as well as the production of hazardous secondary compounds that are toxic and carcinogenic. In this study, Chitosan and Chitosan-zinc oxide (ZnO) nanocomposite were prepared and selected as a low-cost adsorbent with high adsorption capacity for removing reactive red 198 (RR 198) dye from contaminated. After preparation, it was characterized using Fourier-transform infrared spectroscopy [FT-IR], X-ray diffraction spectrophotometer [XRD], and scanning electron microscopy [SEM]. The effect of pH, temperature, time, adsorbent amount, and initial dye concentration were investigated in the removal efficiency of reactive red 198 (RR 198) dyes. The results showed that the maximum adsorption capacity (qm) obtained from the Langmuir equation was 172.41 mg/g in adsorbent dose of 0.1 g/L, pH: 4, temperature of 25°C, adsorption time of 40 min. The thermodynamic parameters demonstrated the spontaneous and endothermic nature of the adsorption process. Due to the high efficiency of chitosan/ZnO nanocomposite in removal of RR 198 from water and advantages such as high adsorption capacity, simple synthesis, and easy application, it can be used as an effective method in removal of RR 198 from water.

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Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118692 ◽

1985 ◽

Vol 43 ◽

pp. 364-365

Author(s):

K.M. Hones ◽

P. Sheldon ◽

B.G. Yacobi ◽

A. Mason

Keyword(s):

High Efficiency ◽

Lattice Mismatch ◽

Low Cost ◽

Growth Conditions ◽

Nonradiative Recombination ◽

Device Structure ◽

Si Substrates ◽

Transmission Electron ◽

Dislocation Densities ◽

Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

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Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

10.26434/chemrxiv.7991129 ◽

2019 ◽

Author(s):

Charlys Bezerra ◽

Géssica Santos ◽

Marilia Pupo ◽

Maria Gomes ◽

Ronaldo Silva ◽

...

Keyword(s):

Thermal Decomposition ◽

Polyvinyl Alcohol ◽

High Efficiency ◽

Electrochemical Impedance ◽

Pechini Method ◽

Low Cost ◽

Charge Transfer Resistance ◽

Transfer Resistance ◽

Calcination Temperatures ◽

Service Lifetime

Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO2–IrO2 anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO2 and IrO2 have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO2–IrO2 anodes with improved properties that can be further extended to synthesise other MMO compositions.

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Light-Weight, Low Cost, High-Efficiency Solar Cells Space Planar Arrays.

10.21236/adb209013 ◽

1996 ◽

Author(s):

Michael L. Timmons

Keyword(s):

Solar Cells ◽

High Efficiency ◽

Low Cost ◽

Light Weight ◽

Planar Arrays ◽

High Efficiency Solar Cells

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Contradiction Analysis and Solution in the R&D of High-Power Solar LED Street Lamp Controller

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180314141920 ◽

2019 ◽

Vol 12 (1) ◽

pp. 12-19

Author(s):

Zhengwang Xu ◽

Wei Mei ◽

Jiaqi Yu ◽

Jiarui Zhang ◽

Yuchun Yi ◽

...

Keyword(s):

Power Supply ◽

High Efficiency ◽

Low Cost ◽

Solar Panel ◽

Battery Voltage ◽

Supply Circuit ◽

Led Light ◽

Power Supply Circuit ◽

Side Mode ◽

Dual Power

As being restricted by factors such as cost, efficiency and size, the development of high-power solar LED street light controller is faced with plenty of difficulties. In case that a structure of two independent DC/DC is applied as the main circuit, it has to face problems such as large size and high cost; in case of applying the bidirectional BUCK/BOOST circuit, it requires change-over switches to control the solar panel and LED light. As being restricted by withstanding voltage, on-resistance and cost, a PMOS device cannot be used as the change-over switch of solar panel and LED light. However, when being used as a change-over switch, an NMOS device must apply the low-side mode under which the negative ends of the mentioned three parts are cut off. In the condition of applying the low-side mode, a differential circuit must be used to detect the voltage of the solar panel. Furthermore, in order to make sure batteries can still be regularly charged after wearing out in daylight, the controller must be supplied with power through a dual power supply circuit that can obtain power from both the solar panel and the battery. The demander has a requirement on extremely low standby power consumption of the product, and thus it is necessary to minimize the circuit that is live while working in standby mode. Methods: The bidirectional BUCK/BOOST circuit structure is applied to the main circuit to realize a higher change-over efficiency while giving considerations to both cost and size. The NMOS device, model IRFB4410ZPBF, with a price of about three yuan, is used as the switching device, and the low-side mode is applied, that is the switches inserted in between negative end of the solar panel or LED light and that of the DC/DC circuit. The low-cost rail-to-rail operational amplifier LM358 is used to form a differential amplification circuit for detecting the voltage of the solar panel. A XL1509-12E1 chip that only costs 0.88 yuan/pc is selected as the main change-over chip for the power supply, which has realized the highly-efficient and low-cost change-over of the power supply. A dual power supply circuit and a step-down protective circuit are designed for the XL1509-12E1 change-over chip. By comparing solar panel voltage with battery voltage, the solar panel booting circuit is realized. Only when solar panel voltage is higher than battery voltage, does the system program start to power it up for running, so that the outage of most of the circuits of the system under standby mode does not consume energy. Furthermore, the solar panel voltage detecting circuit, the solar panel booting circuit and several return difference functions are corrected during system debugging. Results: The circuit board of the entire controller features small size, low cost and high efficiency. It measures about 100*62*18mm in size, costs about 60 yuan, and the charge/discharge change-over efficiency reaches up to over 95%. The controller has many functions: it is capable of operating within a large scope, in which, solar panel voltage is subject to 15~50V, LED light voltage is subject to 15~60V, battery voltage is subject to 10~35V and battery-end charge/discharge current is 10A; it is capable of adapting to monocrystalline silicon/multicrystalline silicon/thin-film and many other kinds of solar panels, as well as lithium/lead-acid and many other kinds of batteries; it is capable of detecting the conversion of day and night, automatically controlling charging and discharging and automatically making adaptive adjustment according to seasonal variations; the current to be consumed during standby will be maintained below 3mA, and thus the power consumption is extremely low. Conclusion: By selecting the bidirectional BUCK/BOOST circuit structure, applying low-side mode for switching of solar panel and LED light, using a differential circuit to detect solar panel voltage, using a low-cost DC/DC chip to realize power supply change-over, designing a dual power supply circuit, introducing solar panel booting circuit and other hardware design, as well as MPPT algorithm, state recognition and control, return difference control and other software design, a solar LED street light control product featuring small size, low cost, high efficiency and multiple functions is successfully developed.

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