scholarly journals Sulfidizing Behavior of Complex Lead-Silver Ore: A Flotation Study

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 434
Author(s):  
Yibing Zhang ◽  
Jianhua Chen
Keyword(s):  
Closed Circuit ◽  
Low Grade ◽  
Circuit Testing ◽  
Silver Recovery ◽  
Total Recovery ◽  
Recovery Yield ◽  
Industrial Sites ◽  
Chemical Phase ◽  
Lead Recovery ◽  
Different Types

In this study, we investigate a low-grade oxidized lead ore containing noble metal silver, with complex mineralogy. The sulfurization behaviors of different types of lead-silver minerals at different pH values were analyzed using the chemical phase analysis method. The interactions between different types of lead-silver minerals and different types of collectors were investigated. An effective laboratory process was developed, and closed-circuit tests were carried out at industrial sites. We found that the order of difficulty for sulfidizing various lead minerals and silver minerals was (PbFe6(OH)12SO4)4 < PbCO3 < PbSO4 < Pb5(P/As/VO4)3Cl; Ag2AsS2 < AgCl < natural-Ag. Aerophine 3418A had the best selectivity and capture capacity of the silver minerals. In the laboratory, the total recovery of lead and silver was 65.16% and 87.81%, respectively. In industrial closed-circuit testing, flotation alone was used, which produced a total lead recovery yield of 67.71%, and a total silver recovery yield of 87.64%.

scholarly journals Assessment of the mercury contamination of landfilled and recovered foundry waste – a case study

2021 ◽  
Vol 19 (1) ◽  
pp. 462-470
Author(s):  
Marta Bożym ◽  
Beata Klojzy-Karczmarczyk
Keyword(s):  
Negative Impact ◽  
Mercury Content ◽  
Mercury Contamination ◽  
Reference Level ◽  
Organic Carbon Content ◽  
Foundry Sands ◽  
Industrial Sites ◽  
Different Types ◽  
Main Component

Abstract Environmental pollution by mercury is a local problem in Poland and concerns mainly industrial sites. Foundry waste are usually characterized by low mercury content compared to other heavy metals. Spent foundry sands with low content of Hg are the main component of foundry waste. However, Hg may be present in foundry dust, which may also be landfilled. Due to Hg toxicity, even a minimal content may have a negative impact on biota. This study focuses on assessing the mercury content of landfilled foundry waste (LFW), to assess its toxicity. Currently tested waste is recovered and reused as a road aggregate. The results were compared with the mercury content of local soils as the reference level. Waste samples were taken from foundry landfill. The mercury content, fractional composition, organic matter (OM) and total organic carbon content, pH and elementary composition of waste were analysed. It was found that the mercury content in LFW was very low, at the level of natural content in soils and did not pose a threat to the environment. The statistical analysis shows that mercury was not associated with OM of the waste, in contrast to soils, probably due to different types of OM in both materials.

scholarly journals Adiponectin as Link Factor between Adipose Tissue and Cancer

2019 ◽  
Vol 20 (4) ◽  
pp. 839 ◽  
Author(s):  
Erika Di Zazzo ◽  
Rita Polito ◽  
Silvia Bartollino ◽  
Ersilia Nigro ◽  
Carola Porcile ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Immune Cells ◽  
Active Role ◽  
Low Grade ◽  
Poor Clinical Outcome ◽  
Different Types ◽  
Obesity And Cancer ◽  
Low Grade Inflammation ◽  
Circulating Levels ◽  
Proliferation And Invasion

Adipose tissue is a key regulator of energy balance playing an active role in lipid storage as well as in synthesizing several hormones directly involved in the pathogenesis of obesity. Obesity represents a peculiar risk factor for a growing list of cancers and is frequently associated to poor clinical outcome. The mechanism linking obesity and cancer is not completely understood, but, amongst the major players, there are both chronic low-grade inflammation and deregulation of adipokines secretion. In obesity, the adipose tissue is pervaded by an abnormal number of immune cells that create an inflammatory environment supporting tumor cell proliferation and invasion. Adiponectin (APN), the most abundant adipokine, shows anti-inflammatory, anti-proliferative and pro-apoptotic properties. Circulating levels of APN are drastically decreased in obesity, suggesting that APN may represent the link factor between obesity and cancer risk. The present review describes the recent advances on the involvement of APN and its receptors in the etiology of different types of cancer.

scholarly journals The effect of the type of fixators reinforcement on strength and deformation characteristics of reinforced concrete

2019 ◽  
Vol 97 ◽  
pp. 02034
Author(s):  
Evgenij Borisyuk
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Steel Reinforcement ◽  
Low Grade ◽  
High Grade ◽  
Building Structures ◽  
Deformation Characteristics ◽  
Reliable Operation ◽  
Different Types ◽  
Strength And Deformation

Rebar fixators of various types (plastic and concrete) became widespread with manufacturing of building structures of precast and monolithic reinforced concrete in order to fix steel reinforcement cage in strictly design position and to exclude the probability of its displacement during concreting. Such sufficiently rigid fixing is necessary for the following reliable operation of the structure in the building, as well as for the preservation of steel reinforcement which protected by a necessary layer of concrete from corrosion. Information available in the literature does not allow us to judge about the effects that different types of fixators apply to exploitative properties (such as strength and crack resistance) of reinforced concrete. The experiments, according to the accepted method, showed that these characteristics are slightly worse for the samples with plastic fixators and fixators made of low grade concrete than for the samples without fixators or fixators made of high grade concrete. On the base on the research results it becomes possible to substantiate the distinction between the areas of application of plastic and concrete fixatives

scholarly journals Beneficiation research on a low grade linnaeite ore with hema-tite-pyrite type

2019 ◽  
Vol 136 ◽  
pp. 02008
Author(s):  
Xinfang Zhang ◽  
Qinqin Wang ◽  
Chengdong Wang ◽  
Lang Zhu ◽  
Shujie Shi ◽  
...  
Keyword(s):  
Copper Sulfate ◽  
Recovery Rate ◽  
Closed Circuit ◽  
Low Grade ◽  
Butyl Xanthate ◽  
Ethyl Xanthate ◽  
Type Complex

Mineralogy and separation experiments were carried out for a low-grade linnaeite ore (0.052%), which belonged to limonite-hematite-pyrite type complex mineral. Under the grinding fineness of 80% -0.074 mm, linnaeite concentrate which contained cobalt grade of 0.51%, recovery rate of 80.99%, sulfur grade of 23.79%, recovery of 88.03% was obtained by closed-circuit processes of one roughing, two scaenging and one cleaning, which used sulfate acid (4500 g/t) and copper sulfate (300 g/t) as activator, so-dium silicate (1000 g/t) and CMC (30 g/t) as inhibitor, ethyl xanthate（100 g/t）and butyl xanthate (100 g/t) as collector, 2# oil (40 g/t) as forther in roughing, no agent in cleaing and first scavenging, used ethyl xan-thate（50 g/t）and butyl xanthate (50 g/t) as collector, 2# oil (20 g/t) as forther in second scavenging.

Influence of Salt Quantity on Recovery Yield of Heterogeneous Aluminium Scrap

2016 ◽  
Vol 1139 ◽  
pp. 16-19
Author(s):  
Stefano Capuzzi ◽  
Giulio Timelli ◽  
Leonardo Capra ◽  
Luca Romano
Keyword(s):  
Analysis Of Variance ◽  
Aluminium Content ◽  
Recovery Yield ◽  
Different Types ◽  
Anderson Darling

The influence of the salt quantity on the recovery yield of aluminium scrap was studied considering an heterogeneous charge. The analysed heterogeneous charge was composed by different types of scrap such as turning, shredded materials and dross. The amount of salt was related to the scrap quality using the salt factor, which is defined as the ratio between the non-aluminium content in the scrap and the quantity of salt required. Two levels of salt factor were considered, 1.2 and 1.8. The analysis of variance was then implemented to verify the influence of the salt quantity on the recovery yield. The results were statistically confirmed using the Anderson-Darling test, the Dixon’s outliers test and the coefficient of variance. An increment of the recovery yield from 95% to 97% was revealed by increasing the salt factor from 1.2 to 1.8.

scholarly journals Unsafe Abortion: Changing Pattern of an Avoidable Tragedy

2016 ◽  
Vol 10 (2) ◽  
pp. 19-23
Author(s):  
A Agrawal ◽  
MC Regmi ◽  
P Rijal ◽  
DK Uprety ◽  
J Agrawal
Keyword(s):  
South African ◽  
Current Trend ◽  
Low Grade ◽  
Unsafe Abortion ◽  
Oral Drugs ◽  
Obstetrics And Gynaecology ◽  
Incomplete Abortion ◽  
Different Types ◽  
Common Clinical Presentation ◽  
A Prospective Study

Aims: The study was done to analyze current trend of unsafe abortion.Methods: It was a prospective study where all the abortion related admissions from January 2009 to December 2011, in Obstetrics and Gynaecology unit at B.P. Koirala Institute of Health Sciences were analyzed. Sixty-six women with diagnosis of unsafe abortion were enrolled in the study. Cases of unsafe abortion were identified and classified using the classification developed by The South African National Incomplete Abortion Study conducted in 1994. Morbidity pattern was compared among the patients using the above classification system.Results: There were 66 cases of unsafe abortion admitted in three years. Most common mode of unsafe abortion was by taking different types of oral drugs in various doses prescribed by medical shops, in 65.2% of women.  Most common clinical presentation was heavy vaginal bleeding in 77% of women. After evaluation, commonest diagnosis made was incomplete abortion in 56.1% of women. In 57.6% of women, unsafe abortion was of low grade. In previous similar study done at the same centre, 16 (22.8%) of unsafe abortions were of low grade, 17 (24.2%) were of moderate grade and 37 (52.8%) were of high grade.Conclusions:  Unsafe abortion is still a significant medical and social problem. The mode of unsafe abortion, presentation and morbidity has changed significantly in recent years. However the morbidity pattern of unsafe abortion is going towards low grade.

scholarly journals Novel methodology for assessing total recovery time in response to unexpected perturbations while walking

2019 ◽  
Author(s):  
Uri Rosenblum ◽  
Lotem Kribus-Shmiel ◽  
Gabi Zeilig ◽  
Yotam Bahat ◽  
Shani Kimel-Naor ◽  
...  
Keyword(s):  
Recovery Time ◽  
Center Of Mass ◽  
Principal Component ◽  
Random Order ◽  
Step Length ◽  
Step Width ◽  
Total Recovery ◽  
Age Related ◽  
Different Types ◽  
Anterior Posterior

AbstractWalking stability is achieved by adjusting the medio-lateral and anterior-posterior dimensions of the base of support (step length and step width, respectively) to contain an extrapolated center of mass. We aimed to calculate total recovery time after different types of perturbations during walking, and use it to compare young and older adults following different types of perturbations. Walking trials were performed in 12 young (age 26.92 ± 3.40 years) and 12 older (age 66.83 ± 1.60 years) adults. Perturbations were introduced at different phases of the gait cycle, on both legs and in anterior-posterior or medio-lateral directions, in random order. A novel algorithm was developed to determine total recovery time values for regaining stable step length and step width parameters following the different perturbations and compared between the two participant groups under low and high cognitive load conditions, using principal component analysis (PCA). We analyzed 829 perturbations each for step length and step width. The algorithm successfully estimated total recovery time in 91.07% of the runs. PCA and statistical comparisons showed significant differences in step length and step width recovery times between anterior-posterior and medio-lateral perturbations, but no age-related differences. Initial analyses demonstrated the feasibility of comparisons based on total recovery time calculated using our algorithm.

scholarly journals Research on Enrichment of P2O5 from Low-Grade Carbonaceous Phosphate Ore via Organic Acid Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Fei Xie ◽  
Jie Zhang ◽  
Jiyan Chen ◽  
Jianrui Wang ◽  
Lin Wu
Keyword(s):  
Organic Acid ◽  
Reaction Times ◽  
Acid Leaching ◽  
Gangue Mineral ◽  
Low Grade ◽  
Reaction Conditions ◽  
Phosphate Ore ◽  
Orthogonal Experiments ◽  
Different Types ◽  
Acid Acid

The theory of using dilute organic acid solutions to leach the carbonaceous part from low-grade carbonaceous phosphate ore has been proposed by researchers as an effective approach to increase the proportion of P and to utilize the abundant low-grade resource. In this paper, a comprehensive experimental study was carried out to confirm the feasibility of organic acid leaching and investigate the optimized leaching conditions. Utilizing the low-grade carbonaceous phosphate ore produced in Zhijin, southwest of China, the effects of different types of acid, acid concentrations, reaction temperatures, reaction times, and liquid-solid ratios on leaching rate of P2O5 were evaluated using single-factor experiments and orthogonal experiments. The reaction mechanism, examined by SEM technique and the reaction thermodynamic analysis suggested that the leaching of P2O5 mainly resulted from the process of dissolution of dolomite (the main gangue mineral) in organic acid, consequently enriching the phosphate rock (the mineral of value). The effectiveness and impacts of different types of acid and reaction conditions were also studied. To conclude, this study first confirmed the viability of enriching P2O5 from low-grade ores through organic acid leaching the carbonaceous part by experimental data, and the experimental results will provide an essential scientific support for further upgrade of the technology to commercial scale utilization.

Landfill mining : potential source for maintenance-free construction materials?

2017 ◽  
Author(s):  
Aarne Saareväli
Keyword(s):  
Construction Materials ◽  
Plastic Waste ◽  
Polymer Chains ◽  
Single Type ◽  
Low Grade ◽  
Vast Number ◽  
Plastic Recycling ◽  
Plastic Bags ◽  
Free Construction ◽  
Different Types

As the use of plastic products is very widespread, reuse of the plastic waste represents a huge challenge. Plastic packaging (e.g. thin plastic bags, foil, foodwrappings) and other plastic waste (pallets, garden furniture, buckets, sport and hobby equipment, car bumpers, canisters, pipes, bobbins, computer and TV cases, plastic refrigerator details, etc.) form the most problematic and continuously growing type of waste, that according to common solutions can be mainly landfilled, or incinerated.Initial sorting of waste and subsequent recycling of single-type plastics into uniform mass, granules or new products are the generally preferred solutions for recycling plastic. Recycling is normally performed based on one specific type of plastic, e.g. LDPE, HDPE, PS, PP or PET, in the course of which the sorted plastic waste is washed, shredded, dried and granulated. The biggest problem with mixed plastics is posed by the fact that polymers of different types are immiscible because of their different molecular weights and long polymer chains. Heating the polymers is not sufficient for decomposing polymer molecules; therefore, the polymers to be recovered must typically have identical compositions to achieve effective mixing. When plastics of different types are simultaneously melted together, they usually do not mix – like oil and water – and will form layers. Low-grade mixed dirty plastic is typically rejected from recycling. Rexest Grupp Ltd, however, has developed a technology for recycling mixed plastic waste.In this study it has been discovered that mixed plastic waste that was landfilled for over a decade did not differentiate from the fresh mixed plastic, neither had the landfilled plastic lost its polymeric properties. Landfilled plastic needs only to be separated from other materials (eg textile, paper) and soil. After mechanical separation, recycling technologies that are able to use of mixed plastic waste, were as also able to handle mixed landfill plastic.Experiments demonstrate that construction materials and products like decking boards, noise barriers, garden furniture etc. could therefore be produced also from landfilled plastic waste, turning this waste into the maintenance free products that are also recyclable after decades of use. Taking into account vast number of landfills that contain plastic waste it raises question whether turning these materials into recyclable construction materials could form a new challenge and possibility to support the environment, and lower the need for the usage of new resources.

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