Use of Multi-Anionic Sodium Tripolyphosphate to Enhance Dispersion of Concentrated Kaolin Slurries in Seawater

This research aims to analyze the impact of sodium tripolyphosphate (STPP) as a rheological modifier of concentrated kaolin slurries in seawater at pH 8, which is characteristic of copper sulfide processing operations. The dispersion phenomenon was analyzed through chord length measurements using the focused beam reflectance measurement (FBRM) technique, complementing size distributions in unweighted and square-weighted modes. The reduction of the rheological properties was significant, decreasing from 231 Pa in a reagent-free environment to 80 Pa after the application of STPP. A frequency sweep in a linear viscoelastic regime indicated that by applying a characteristic dosage of 0.53 kg/t of STPP, the pulp before yielding increases its phase angle, which increases its liquid-like character. Measurements of the chord length verified the dispersion of particles, which showed an apparent increase in the proportion of fine particles and a reduction of the coarser aggregates when STPP was applied. Measurements of the zeta potential suggested that the high anionic charge of the reagent (pentavalent) increases the electrostatic repulsions between particles, overcoming the effect of cations in seawater. The results are relevant for the mining industry, especially when the deposits have high contents of complex gangues, such as clays, that increase the rheological properties. This increases the energy costs and water consumption needed for pumping the tailings from thickeners to the tailing storages facilities. The strategies that allow for the improvement of the fluidity and deformation of the tailings generate slack in order to maximize water recovery in the thickening stages.

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Reducing Magnesium within Seawater Used in Mineral Processing to Improve Water Recovery and Rheological Properties When Dewatering Clay-Based Tailings

Polymers ◽

10.3390/polym14020339 ◽

2022 ◽

Vol 14 (2) ◽

pp. 339

Author(s):

Matías Jeldres ◽

Norman Toro ◽

Sandra Gallegos ◽

Pedro Robles ◽

Iván Salazar ◽

...

Keyword(s):

Yield Stress ◽

Aggregate Size ◽

Complete Removal ◽

Mineral Processing ◽

Water Recovery ◽

Concentrated Suspensions ◽

Reflectance Measurement ◽

Pre Treatment ◽

A Minor ◽

The Impact

In areas where access to water for mineral processing is limited, the direct use of seawater in processing has been considered as an alternative to the expense of its desalination. However, efficient flotation of copper sulfides from non-valuable phases is best achieved at a pH > 10.5, and raising the pH of seawater leads to magnesium precipitates that adversely affect subsequent tailings dewatering. Seawater pre-treatment with lime can precipitate the majority of magnesium present, with these solids then being removed by filtration. To understand how such treatment may aid tailings dewatering, treated seawater (TSw) was mixed with raw seawater (Rsw) at different ratios, analyzing the impact on the flocculated settling rate, aggregate size as measured by focused beam reflectance measurement (FBRM), and vane yield stress for two synthetic clay-based tailings. A higher proportion of Tsw (10 mg/L Mg2+) led to larger aggregates and higher settling rates at a fixed dosage, with FBRM suggesting that higher calcium concentrations in Tsw may also favor fines coagulation. The yield stress of concentrated suspensions formed after flocculation decreased with higher proportions of Tsw, a consequence of lower flocculant demand and the reduced presence of precipitates; while the latter is a minor phase by mass, their high impact on rheology reflects a small particle size. Reducing magnesium concentrations in seawater in advance of use in processing offers advantages in the water return from thickening and subsequent underflow transport. However, this may not require complete removal, with blending Tsw and Rsw an option to obtain acceptable industrial performance.

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The Impact of Durian Rind in Water-based Mud in Combating Lost Circulation

Jurnal Teknologi ◽

10.11113/jt.v74.3323 ◽

2015 ◽

Vol 74 (1) ◽

Author(s):

Issham Ismail ◽

Anum Bisyarah Mohd Nor ◽

Mohd. Fauzi Hamid ◽

Abdul Razak Ismail

Keyword(s):

Rheological Properties ◽

Hot Rolling ◽

Fine Particles ◽

Drilling Fluid ◽

Performance Comparison ◽

Optimum Concentration ◽

Lost Circulation ◽

Water Based ◽

The Impact ◽

Durian Rind

A laboratory investigation has been done on durian rind, a fibrous material, as an alternative lost circulation material in water-based mud. The experimental works covered the rheological properties and lost circulation tests which were conducted before and after the hot-rolling tests as per API RP 13B. Those tests involved the use of standard mud testing equipment and a lost circulation test cell. The optimum concentration of the durian rind―which had been cleaned, cut into small pieces, dried in an oven at 60°C for 24 hours, and ground into small fine particles―was determined before a performance comparison study was done on both Hydro-plug (i.e., a commercial lost circulation material) and durian rind of different sizes, namely fine (0.5 mm), medium (1.0 mm), and coarse (2.0 mm). The experimental results showed that the durian rind worked well in combating the lost circulation. At its optimum concentration of 20 lb/bbl, the coarse durian rind was found to have performed excellently in combating lost circulation in 1 mm and 2 mm fractures. The standard rheological test showed that the rheological properties of drilling fluid were not too affected at standard temperature of 75°F but they changed significantly after the hot-rolling tests. The change in rheological properties was due to the flocculation of bentonite and chemical reaction of the pectin in durian rind.

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The Impact of Longer Consultation Time: A Simulation-Based Approach

Applied Clinical Informatics ◽

10.1055/s-0040-1721320 ◽

2020 ◽

Vol 11 (05) ◽

pp. 857-864

Author(s):

Abdulrahman M. Jabour

Keyword(s):

Waiting Time ◽

Quality Care ◽

Working Hours ◽

Discrete Events ◽

Simulation Based ◽

Patient Waiting Time ◽

Free Environment ◽

The Impact ◽

Consultation Time ◽

Patient Waiting

Abstract Background Maintaining a sufficient consultation length in primary health care (PHC) is a fundamental part of providing quality care that results in patient safety and satisfaction. Many facilities have limited capacity and increasing consultation time could result in a longer waiting time for patients and longer working hours for physicians. The use of simulation can be practical for quantifying the impact of workflow scenarios and guide the decision-making. Objective To examine the impact of increasing consultation time on patient waiting time and physician working hours. Methods Using discrete events simulation, we modeled the existing workflow and tested five different scenarios with a longer consultation time. In each scenario, we examined the impact of consultation time on patient waiting time, physician hours, and rate of staff utilization. Results At baseline scenarios (5-minute consultation time), the average waiting time was 9.87 minutes and gradually increased to 89.93 minutes in scenario five (10 minutes consultation time). However, the impact of increasing consultation time on patients waiting time did not impact all patients evenly where patients who arrive later tend to wait longer. Scenarios with a longer consultation time were more sensitive to the patients' order of arrival than those with a shorter consultation time. Conclusion By using simulation, we assessed the impact of increasing the consultation time in a risk-free environment. The increase in patients waiting time was somewhat gradual, and patients who arrive later in the day are more likely to wait longer than those who arrive earlier in the day. Increasing consultation time was more sensitive to the patients' order of arrival than those with a shorter consultation time.

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Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis

Environmental Science: Atmospheres ◽

10.1039/d1ea00025j ◽

2021 ◽

Author(s):

Weiqi Xu ◽

Chun Chen ◽

Yanmei Qiu ◽

Conghui Xie ◽

Yunle Chen ◽

...

Keyword(s):

Radiative Forcing ◽

North China Plain ◽

North China ◽

Fine Particles ◽

Large Fraction ◽

Organic Aerosol ◽

Size Distributions ◽

The North ◽

The Impact

Organic aerosol (OA), a large fraction of fine particles, has a large impact on climate radiative forcing and human health, and the impact depends strongly on size distributions. Here we...

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Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-777-2016 ◽

2016 ◽

Vol 16 (2) ◽

pp. 777-797 ◽

Cited By ~ 29

Author(s):

A Vara-Vela ◽

M. F. Andrade ◽

P. Kumar ◽

R. Y. Ynoue ◽

A. G. Muñoz

Keyword(s):

Size Distribution ◽

Metropolitan Area ◽

Atmospheric Aerosols ◽

Fine Particles ◽

Sao Paulo ◽

Vehicular Emissions ◽

São Paulo ◽

Mass Size Distribution ◽

Mass Size ◽

The Impact

Abstract. The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤  2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40–50 % of the total PM10 (i.e. those ≤  10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the ultraviolet radiation and induced a decrease in ozone formation. The ground-level O3 concentration decreased by about 2 % when the aerosol-radiation feedback is taken into account.

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Relationship between particle-size and chord-length distributions in focused beam reflectance measurement: stability of direct inversion and weighting

Powder Technology ◽

10.1016/s0032-5910(03)00084-6 ◽

2003 ◽

Vol 133 (1-3) ◽

pp. 125-133 ◽

Cited By ~ 78

Author(s):

E.J.W Wynn

Keyword(s):

Particle Size ◽

Chord Length ◽

Reflectance Measurement ◽

Direct Inversion ◽

Focused Beam

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Analysis of the Impact of COVID-19 on the Current Farmer’s Market Business Model and Research on its Transformation in Smoke-Free Environment

Tobacco Regulatory Science ◽

10.18001/trs.7.5.10 ◽

2021 ◽

Vol 7 (5) ◽

pp. 921-932

Author(s):

Zhang Jia ◽

Xu Hui ◽

Zeng Zhi ◽

Yu Jingjing

Keyword(s):

Business Model ◽

Main Direction ◽

Business Model Canvas ◽

The Future ◽

New Business ◽

Free Environment ◽

The Impact

Objectives: The ban on smoking creates a good smoke-free environment for the traditional farmer’s market. However,the suddenly spread COVID-19 has greatly impacted the business model of the traditional smoke-free farmer’s market.Methods: In order to realize the effective transformation of the current farmer’s market, this paper uses the business model canvas of Osterwalder and Pigneur to compare and analyze the traditional smoke-free farmer’s market and the smart farmer’s market. Results:The study found that the new business model promoted by “Smart Farmer” can effectively solve the difficulties and problems faced by the current farmer’s market. Conclusions:On the basis of this research, this paper puts forward the main direction of the future transformation of the farmer’s market business model, in order to provide a theoretical and practical basis for the intellectualized reconstruction of farmer’s market in China.

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The impact of the integrated reporting framework on corporate social responsibility (CSR) disclosures – the case of South African mining companies

Social Responsibility Journal ◽

10.1108/srj-12-2020-0508 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Barry Ackers ◽

Susanna Elizabeth Grobbelaar

Keyword(s):

Corporate Social Responsibility ◽

Social Responsibility ◽

South African ◽

Mining Industry ◽

Integrated Reporting ◽

Content Type ◽

Stakeholder Orientation ◽

Mining Companies ◽

Corporate Social ◽

The Impact

Purpose Despite initially being lauded as a revolutionary approach for companies to account to all stakeholders, the shareholder orientation of the international integrated reporting (<IR>) framework gave rise to questions about whether integrated reports would still sufficiently disclose pertinent corporate social responsibility (CSR) information. This paper aims to investigate the extent to which the <IR> framework has impacted the CSR disclosures contained in integrated reports of South African mining companies. Design/methodology/approach The study deployed a mixed methods research approach, involving thematic content analysis of the CSR disclosures contained in the integrated reports of mining companies with primary listings on the Johannesburg Stock Exchange. The resultant qualitative data were subsequently analysed using a T-test of difference. Findings The study observes that the release of the <IR> framework appears to have had a limited impact on the CSR disclosures in the integrated reports of most companies included in the study. However, where significant differences were identified, the CSR disclosures of some companies were positively impacted after the release of the <IR> framework, whilst others were negatively impacted. Research limitations/implications As South Africa is acknowledged as a leader in the global <IR> movement, the paper’s observations have global relevance and suggest that the fundamental principles of <IR> should be reconsidered to improve the alignment with stakeholders’ information needs, as originally conceived. Originality/value Despite the shareholder orientation of the <IR> framework, the global mining industry is acknowledged as being at the forefront of implementing CSR interventions to mitigate the adverse impacts of their operations on stakeholders, supporting a stakeholder orientation. As the adoption of <IR> continues to gain traction around the world, this paper’s contribution is that it represents one of the few papers to use the global reporting initiative G4 indicators to specifically examine the impact of <IR> framework on the CSR disclosures on the South African mining industry, where both <IR> and CSR reporting are quasi-mandatory disclosure requirements.

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To what extent does the environmental magnetism technique acts as a way of assessing the uptake of atmospheric particles by plants?

10.5194/egusphere-egu21-8263 ◽

2021 ◽

Author(s):

Sarah Letaïef ◽

Pierre Camps ◽

Thierry Poidras ◽

Patrick Nicol ◽

Delphine Bosch ◽

...

Keyword(s):

Air Quality ◽

Endemic Species ◽

Fine Particles ◽

Magnetic Measurements ◽

Deposition Velocity ◽

Environmental Magnetism ◽

Air Pollutant ◽

Atmospheric Pollutants ◽

Area Index ◽

The Impact

Numerous studies have already shown the possibility of tracing the sources, the compositions, and the concentration of atmospheric pollutants deposited on plant leaves. In environmental geochemistry, inter-element and isotope ratios from chemical element assays have been used for these purposes. Alternatively, environmental magnetism represents a quick and inexpensive asset that is increasingly used as a relative indicator for concentrations of air pollutant on bio accumulator surfaces such as plants. However, a fundamental issue is still pending: Do plants in urban areas represent a sink for fine particles that is sufficiently effective to improve air quality? This is a very topical issue because some studies have shown that the foliage can trap fine particles by different dry deposition processes, while other studies based on CFD models indicate that plant hedges in cities can hinder the atmospheric dispersion of pollutants and therefore increase pollution at the level of emission sources such as traffic. To date, no consensus was made because several factors not necessary well known must be taken into account, such as, PM concentration and size, prevailing wind, surface structures, epicuticular wax, to mention just a few examples. A first step toward the understanding of the impact of urban greens on air quality is the precise determination of the deposition velocity (Vd) parameter. This latter is specific for each species and it is most of the time underestimated in modeling-based studies by taking standard values. In that perspective, we built a wind tunnel (6 m long, 86 cm wide and 86 cm high) to perform analogical experiments on different endemic species. All parameters are controlled, i.e, the wind speed, the nature and the injection time of pollutants (Gasoline or Diesel exhausts, brakes or tires dust, etc&#8230;). We can provide the PM concentrations upwind and downwind of natural reconstituted hedges by two dustmeters (LOACs - M&#233;t&#233;oModem). Beforehand, parameters such as the hedge resistance (%) or the leaf area index (LAI) have been estimated for each studied specie to allow comparability between plants removal potential. The interest would ultimately combine PM concentration measured by size bins from the LOACs with magnetic measurements (ARM, IRM100mT, IRM300mT and SIRM) of plant leaves. The idea is to check whether it would be possible to precisely determine in situ the dust removal rate by urban greens with environmental magnetism measurements. Up to now, we have carried out on different endemic species such as Elaeagnus x ebbingei leaves and Mediterranean pine needles, the results of which will be presented.

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Metal Removal from Acid Waters by an Endemic Microalga from the Atacama Desert for Water Recovery

Minerals ◽

10.3390/min8090378 ◽

2018 ◽

Vol 8 (9) ◽

pp. 378 ◽

Cited By ~ 2

Author(s):

Marcela Martínez ◽

Yanett Leyton ◽

Luis Cisternas ◽

Carlos Riquelme

Keyword(s):

Mine Drainage ◽

Metal Removal ◽

Atacama Desert ◽

Mining Industry ◽

Mining Activity ◽

Water Recovery ◽

Metallic Ions ◽

Mineral Extraction ◽

High Concentrations ◽

Acid Waters

The environmental problems generated by waste from the mining industry in the mineral extraction for business purposes are known worldwide. The aim of this work is to evaluate the microalga Muriellopsis sp. as a potential remover of metallic ions such as copper (Cu2+), zinc (Zn2+) and iron (Fe2+), pollutants of acid mine drainage (AMD) type waters. For this, the removal of these ions was verified in artificial acid waters with high concentrations of the ions under examination. Furthermore, the removal was evaluated in waters obtained from areas contaminated by mining waste. The results showed that Muriellopsis sp. removed metals in waters with high concentrations after 4–12 h and showed tolerance to pH between 3 and 5. These results allow proposing this species as a potential bioremediator for areas contaminated by mining activity. In this work, some potential alternatives for application in damaged areas are proposed as a decontamination plan and future prevention.

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