The Effects of Milling and pH on Co, Ni, Zn and Cu Bioleaching from Polymetallic Sulfide Concentrate

Acid bioleaching of a low-grade and polymetallic sulfide concentrate was studied, in order to determine suitable feed material particle size and pH for efficient leaching of valuable metals. The sulfide concentrate consisted of pyrite (50 wt %), pyrrhotite (31 wt %), quartz (10 wt %) and lower amounts of cobalt, nickel, zinc and copper (each <1 wt %). After adaptation of microorganisms in shake flasks, stirred tank tests were conducted at different pH levels and supplementing feed material at different particle sizes (milled to d80 < 150 µm, <50 µm, <28 µm, <19 µm). The operation at pH 1.8 was seen prone to iron precipitation, while this was not observed at a pH between 1.3 and 1.5. Additional milling to decrease particle size from the initial d80 < 150 µm had a major positive effect on cobalt- and nickel-leaching yields, proposing that at least d80 < 28 µm should be targeted. The best leaching yields for the main economic elements, cobalt and nickel, were 98% and 94%, respectively, reached with d80 < 19 µm at pH 1.3. However, it was considered that at pH 1.5, similar results could be obtained. This research sets the basis for continuing the experiments at a continuous pilot scale.

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Leaching Behaviour of Construction and Demolition Wastes and Recycled Aggregates: Statistical Analysis Applied to the Release of Contaminants

Applied Sciences ◽

10.3390/app11146265 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6265

Author(s):

Alessandra Diotti ◽

Giovanni Plizzari ◽

Sabrina Sorlini

Keyword(s):

Particle Size ◽

Statistical Analysis ◽

Raw Materials ◽

Primary Source ◽

Recycled Aggregates ◽

Critical Parameters ◽

Material Particle ◽

Analysis Methodology ◽

Construction And Demolition Wastes ◽

Leaching Behaviour

Construction and demolition wastes represent a primary source of new alternative materials which, if properly recovered, can be used to replace virgin raw materials partially or totally. The distrust of end-users in the use of recycled aggregates is mainly due to the environmental performance of these materials. In particular, the release of pollutants into the surrounding environment appears to be the aspect of greatest concern. This is because these materials are characterized by a strong heterogeneity which can sometimes lead to contaminant releases above the legal limits for recovery. In this context, an analysis of the leaching behaviour of both CDWs and RAs was conducted by applying a statistical analysis methodology. Subsequently, to evaluate the influence of the particle size and the volumetric reduction of the material on the release of contaminants, several experimental leaching tests were carried out according to the UNI EN 12457-2 and UNI EN 12457-4 standards. The results obtained show that chromium, mercury, and COD are the most critical parameters for both CDWs and RAs. Moreover, the material particle size generally affects the release of contaminants (i.e., finer particles showed higher releases), while the crushing process does not always involve higher releases than the sieving process.

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Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics

Green Processing and Synthesis ◽

10.1515/gps-2021-0008 ◽

2021 ◽

Vol 10 (1) ◽

pp. 157-168

Author(s):

Biwei Luo ◽

Pengfei Li ◽

Yan Li ◽

Jun Ji ◽

Dongsheng He ◽

...

Keyword(s):

Particle Size ◽

Fly Ash ◽

Reaction Time ◽

Carbothermal Reduction ◽

Industrial Waste ◽

Phosphate Rock ◽

Molar Ratio ◽

Low Grade ◽

Carbon Excess ◽

Fluxing Agent

Abstract The feasibility of industrial waste fly ash as an alternative fluxing agent for silica in carbothermal reduction of medium-low-grade phosphate ore was studied in this paper. With a series of single-factor experiments, the reduction rate of phosphate rock under different reaction temperature, reaction time, particle size, carbon excess coefficient, and silicon–calcium molar ratio was investigated with silica and fly ash as fluxing agents. Higher reduction rates were obtained with fly ash fluxing instead of silica. The optimal conditions were derived as: reaction temperature 1,300°C, reaction time 75 min, particle size 48–75 µm, carbon excess coefficient 1.2, and silicon–calcium molar ratio 1.2. The optimized process condition was verified with other two different phosphate rocks and it was proved universally. The apparent kinetics analyses demonstrated that the activation energy of fly ash fluxing is reduced by 31.57 kJ/mol as compared with that of silica. The mechanism of better fluxing effect by fly ash may be ascribed to the fact that the products formed within fly ash increase the amount of liquid phase in the reaction system and promote reduction reaction. Preliminary feasibility about the recycling of industrial waste fly ash in thermal phosphoric acid industry was elucidated in the paper.

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Distinct Roles of Acidophiles in Complete Oxidation of High-Sulfur Ferric Leach Product of Zinc Sulfide Concentrate

Microorganisms ◽

10.3390/microorganisms8030386 ◽

2020 ◽

Vol 8 (3) ◽

pp. 386 ◽

Cited By ~ 3

Author(s):

Maxim Muravyov ◽

Anna Panyushkina

Keyword(s):

Microbial Community ◽

Zinc Sulfide ◽

Elemental Sulfur ◽

Waste Product ◽

Sulfur Oxidation ◽

Low Grade ◽

Sulfide Concentrates ◽

Sulfide Concentrate ◽

Elemental Sulfur Oxidation ◽

Ferric Leaching

A two-step process, which involved ferric leaching with biologically generated solution and subsequent biooxidation with the microbial community, has been previously proposed for the processing of low-grade zinc sulfide concentrates. In this study, we carried out the process of complete biological oxidation of the product of ferric leaching of the zinc concentrate, which contained 9% of sphalerite, 5% of chalcopyrite, and 29.7% of elemental sulfur. After 21 days of biooxidation at 40 °C, sphalerite and chalcopyrite oxidation reached 99 and 69%, respectively, while the level of elemental sulfur oxidation was 97%. The biooxidation residue could be considered a waste product that is inert under aerobic conditions. The results of this study showed that zinc sulfide concentrate processing using a two-step treatment is efficient and promising. The microbial community, which developed during biooxidation, was dominated by Acidithiobacillus caldus, Leptospirillum ferriphilum, Ferroplasma acidiphilum, Sulfobacillus thermotolerans, S. thermosulfidooxidans, and Cuniculiplasma sp. At the same time, F. acidiphilum and A. caldus played crucial roles in the oxidation of sulfide minerals and elemental sulfur, respectively. The addition of L. ferriphilum to A. caldus during biooxidation of the ferric leach product proved to inhibit elemental sulfur oxidation.

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Surface and Catalytic Properties of NiO and Co3O4 Solids Doped with Cobalt and Nickel Ions

Adsorption Science & Technology ◽

10.1260/026361702320644752 ◽

2002 ◽

Vol 20 (5) ◽

pp. 467-484

Author(s):

G.A. El-Shobaky ◽

A.M. Turky ◽

A.M. Ghozza

Keyword(s):

Particle Size ◽

Thermal Treatment ◽

Surface Area ◽

Catalytic Properties ◽

Excess Oxygen ◽

Average Particle ◽

Surface Excess ◽

Nickel Ions ◽

Nickel Species ◽

Cobalt And Nickel

The effects of doping NiO and Co3O4 solids with cobalt and nickel species on their surface and catalytic properties were investigated. The amounts of dopant, in the form of the corresponding nitrate, were varied between 0.5–6.0 mol% cobalt ions and 2.0–6.0 mol% nickel ions. Pure and variously doped solids were subjected to thermal treatment at 300–700°C. The techniques employed were XRD, nitrogen adsorption at −196°C, decomposition of H2O2 at 30–50°C and estimation of the amount of surface excess oxygen on the variously prepared solids as determined by the hydrazine method. The results obtained revealed that the pure and variously doped NiO samples precalcined at 300°C consisted of a finely divided NiO phase having an average particle size of ca. 40 Å. Pure and variously doped Co3O4 specimens preheated at 500°C and 700°C were composed of a Co3O4 phase with a much bigger particle size (230 Å and 350 Å, respectively, for the solids precalcined at 500°C and 700°C). Doping of NiO followed by thermal treatment at 300°C and 500°C resulted in a measurable decrease in its BET surface area (19–23%), while doping of Co3O4 with nickel species followed by heating at 500°C and 700°C brought about a significant increase in its specific surface area (56–60%). Doping each of the NiO and Co3O4 solids with cobalt and nickel species greatly increased the amount of surface excess oxygen and effected a considerable increase in their catalytic activities. This increase was, however, much more pronounced in the case of NiO which attained a value of ca. 100-fold. Doping of NiO with cobalt species followed by thermal treatment at 300°C and 500°C decreased the activation energy (DE) of the catalyzed reaction to an extent proportional to the amount of dopant added. On the other hand, doping of Co3O4 with nickel species followed by thermal treatment at 500°C and 700°C did not change the value of DE. These results suggest that doping of Co3O4 with nickel species did not modify the mechanism of the catalyzed reaction but increased the concentration of catalytically active sites without changing their energetic nature.

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Characteristics of an air-fluidized-bed biofilm reactor system with a multi-media filter

Water Science & Technology ◽

10.2166/wst.1994.0550 ◽

1994 ◽

Vol 30 (11) ◽

pp. 101-110

Author(s):

Toshiaki Tsubone ◽

Seiichi Kanamori ◽

Tatsuo Takechi ◽

Masahiro Takahashi

Keyword(s):

Particle Size ◽

Fluidized Bed ◽

Suspended Solids ◽

Pilot Scale ◽

Biofilm Reactor ◽

Reactor System ◽

Multi Media ◽

Bod Removal

A pilot scale study was conducted using an Air-Fluidized-Bed Biofilm Reactor (AFBBR) system with a Multi Media Filter (MMF). Soluble BOD (S-BOD) concentration in the effluent of the AFBBR had a correlation with total BOD (T-BOD) and Suspended Solids (SS) concentration in the effluent of the MMF. The lower the S-BOD in the effluent of the AFBBR was, the lower was not only T-BOD but also SS in the effluent of the MMF. It was found that as treatment proceeded, S-BOD was removed and the particle size of SS increased in the AFBBR. These results suggested that the mechanism of BOD removal in this system was: S-BOD was removed and a part of the S-BOD was changed to SS and the particle size of the SS increased in the AFBBR, and then the SS was removed by the MMF. Thus not only the T-BOD but also the SS in the effluent of MMF was lower when the S-BOD in the effluent of the AFBBR was lower. When the S-BOD in the effluent of the AFBBR was 8mg/L, T-BOD and the SS in the effluent of the MMF were 10mg/L and 4mg/L, respectively. In order to have an average S-BOD value in the effluent of the AFBBR of about 8mg/L, the T-BOD loading and the S-BOD loading needed to be less than 1.3kg/m3/day and 0.45 kg/m3/day, respectively. Even when the BOD loading was high, nitrification still occurred in this system.

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Bioleaching of Phosphorus from Low Grade Ores and Concentrates with Acidophilic Iron- and Sulphur-Oxidizing Bacteria

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.825.266 ◽

2013 ◽

Vol 825 ◽

pp. 266-269 ◽

Cited By ~ 2

Author(s):

Tuija H. Sarlin ◽

Outi K. Priha ◽

Mona E. Arnold ◽

Päivi Kinnunen

Keyword(s):

Energy Source ◽

Acidithiobacillus Ferrooxidans ◽

Elemental Sulphur ◽

Phosphorus Leaching ◽

Low Grade ◽

Sulphide Minerals ◽

Bacterial Cultures ◽

Acid Generation ◽

Phosphorus Extraction ◽

Shake Flasks

Bioleaching experiments of phosphorus from low grade fluorapatite ore containing 8.2% P2O5 and from fluorapatite concentrate containing 29.8% P2O5 were carried out in shake flasks. Elemental sulphur was supplemented as an energy source for acid generation. Mixed and pure acidophilic bacterial cultures consisting of iron-and/or sulphur-oxidizing bacteria Acidithiobacillus ferrooxidans, A. thiooxidans and Leptospirillum ferrooxidans were used in the experiments. These acidophiles are commonly used in bioleaching of sulphide minerals, but their application on phosphorus bioleaching has been limited. Phosphorus leaching was shown to be a pH-dependant phenomenon. Phosphorus leaching yields of up to 97% and 28% were obtained in 3 weeks for low grade fluorapatite ore and concentrate, respectively. These results indicate a potential for applying bioleaching for phosphorus extraction from low grade materials.

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Theoretical and Experimental Evaluation of Particle size Effect of Iron , Cobalt ,and Nickel Powders Suspended in Al Dura oil on XRF Intensities

Baghdad Science Journal ◽

10.21123/bsj.4.3.475-481 ◽

2007 ◽

Vol 4 (3) ◽

pp. 475-481

Author(s):

Baghdad Science Journal

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Laser System ◽

Particle Size Effect ◽

Particle Sizes ◽

Iron Cobalt ◽

X Ray ◽

Nickel Powders ◽

Good Agreement ◽

Cobalt And Nickel

Iron , Cobalt , and Nickel powders with different particle sizes were subjected to sieving and He-Ne laser system to determine the particle size . 1wt% from each powders was blended carefully with 99wt% from Iraqi oil . Microscopic examination were carried for all samples to reveal the particle size distribution . A Siemens type SRS sequential wavelength dispersive(WDS) X-ray spectrometer was used to analyze all samples , and the XRF intensity were determined experimentally and theoretically for all suspended samples , Good agreement between theoretical and experimental results were found .

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Assessment of Lost Circulation Material Particle-Size Distribution on Fracture Sealing: A Numerical Study

SPE Drilling & Completion ◽

10.2118/209201-pa ◽

2022 ◽

pp. 1-15

Author(s):

Lu Lee ◽

Arash Dahi Taleghani

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Numerical Study ◽

Fluid Loss ◽

Material Particle ◽

Lost Circulation ◽

Fracture Sealing ◽

Discrete Element Methods ◽

Lost Circulation Materials

Summary Lost circulation materials (LCMs) are essential to combat fluid loss while drilling and may put the whole operation at risk if a proper LCM design is not used. The focus of this research is understanding the function of LCMs in sealing fractures to reduce fluid loss. One important consideration in the success of fracture sealing is the particle-size distribution (PSD) of LCMs. Various studies have suggested different guidelines for obtaining the best size distribution of LCMs for effective fracture sealing based on limited laboratory experiments or field observations. Hence, there is a need for sophisticated numerical methods to improve the LCM design by providing some predictive capabilities. In this study, computational fluid dynamics (CFD) and discrete element methods (DEM) numerical simulations are coupled to investigate the influence of PSD of granular LCMs on fracture sealing. Dimensionless variables were introduced to compare cases with different PSDs. We validated the CFD-DEM model in reproducing specific laboratory observations of fracture-sealing experiments within the model boundary parameters. Our simulations suggested that a bimodally distributed blend would be the most effective design in comparison to other PSDs tested here.

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Analysis the Effect of Charcoal Mass Variation to Ni Content, Sinter Strength and Yield on Sintering Process of Limonitic Laterite Nickel Ore

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.867.25 ◽

2020 ◽

Vol 867 ◽

pp. 25-31

Author(s):

Fakhreza Abdul ◽

Sungging Pintowantoro ◽

Ari Maulidani

Keyword(s):

Nickel Content ◽

Low Grade ◽

Sintering Process ◽

Mass Variation ◽

Feed Material ◽

Nickel Iron ◽

Sinter Strength ◽

Ni Content ◽

Drop Tests ◽

Alternative Processes

The depletion of sulfide nickel ore and the growing of stainless steel demand each year cause the use of low-grade laterite nickel ore continues to increase. Due to very low nickel content, there is no optimal process to extract them. One of the alternative processes being developed now is the sintering-blast furnace process which produces Nickel Pig Iron (NPI). This research was conducted by sintering limonitic laterite nickel ore using charcoal as fuel and limestone as a flux. This research aims to analyze the effect of charcoal mass variation on Ni content, sinter strength, and the yield on the sintering process of limonitic laterite nickel ore. Charcoal and limestone demand calculated using energy balance and mass balance, then varied charcoal mass to feed material. Feed materials are fed in the furnace, heated at a temperature of 1200oC with 4 hours holding time. Next, the sinter yield was calculated. EDX, XRD, and Drop tests were also performed to determine Ni content, sinter compounds, and strength. The highest Ni content was 3.66% which was obtained by adding 9.9 kg charcoal. The highest sinter strength and yield also obtained by adding 9.9 kg charcoal (72.30% and 86.44%, respectively). Mayor phases which formed on sinter with 9.9 kg charcoal addition is nickel-iron oxide.

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Stormwater runoff treatment filtration system and backwashing system

Water Science & Technology ◽

10.2166/wst.2019.097 ◽

2019 ◽

Vol 79 (4) ◽

pp. 771-778 ◽

Cited By ~ 2

Author(s):

Junho Lee ◽

Myungjin Lee

Keyword(s):

Particle Size ◽

Removal Efficiency ◽

Recovery Rate ◽

Stormwater Runoff ◽

Pilot Scale ◽

Solid Loading ◽

Filter Media ◽

Turbidity Removal ◽

Filtration System ◽

Combined Sewer

Abstract This study has been carried out to evaluate the applicability of the pilot scale hybrid type of stormwater runoff treatment system for treatment of combined sewer overflow. Also, to determine the optimum operation parameter such as coagulation dosage concentration, effectiveness of coagulant usage, surface loading rate and backwashing conditions. The pilot scale stormwater filtration system (SFS) was installed at the municipal wastewater plant serving the city of Cheongju (CWTP), Korea. CWTP has a capacity of 280,000 m3/day. The SFS consists of a hydrocyclone coagulation/flocculation with polyaluminium chloride silicate (PACS) and an upflow filter to treat combined sewer overflows. There are two modes (without PACS use and with PACS use) of operation for the SFS. In case of no coagulant use, the range of suspended solids (SS) and turbidity removal efficiency were 72.0–86.6% (mean 80.0%) and 30.9–71.1% (mean 49.3%), respectively. And, the recovery rate of filter was 79.2–83.6% (mean 81.2%); the rate of remaining solid loading in filter media was 16.4–20.8% (mean 18.8%) after backwashing. The influent turbidity, SS concentrations were 59.0–90.7 NTU (mean 72.0 NTU), 194.0–320.0mg/L (mean 246.7mg/L), respectively. The range of PACS dosage concentration was 6.0–7.1mg/L (mean 6.7mg/L). The range of SS and turbidity removal efficiency was 84.9–98.2 (mean 91.4%) and 70.7–96.3 (mean 84.0%), respectively. It was found that removal efficiency was enhanced with PACS dosage. The recovery rate of filter was 92.0–92.5% (mean 92.3%) the rate of remaining solid loading in filter media was 6.1–8.2% (mean 7.2%) after backwashing. In the case of coagulant use, the particle size of the effluent is bigger than influent particle size. The results showed that SFS with PACS use more effective than without PACS use in SS and turbidity removal efficiency and recovery rate of filter.

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