scholarly journals Describing Mining Tailing Flocculation in Seawater by Population Balance Models: Effect of Mixing Intensity

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 240
Author(s):  
Gonzalo R. Quezada ◽  
Luís Ayala ◽  
Williams H. Leiva ◽  
Norman Toro ◽  
Pedro G. Toledo ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Aggregate Size ◽  
Population Balance ◽  
Cost Effective ◽  
Time Dependent ◽  
Balance Model ◽  
Optimal Conditions ◽  
Reflectance Measurement ◽  
Correct Representation

A population balance model (PBM) is used to describe flocculation of particle tailings in seawater at pH 8 for a range of mixing intensities. The size of the aggregates is represented by the mean chord length, determined by the focused beam reflectance measurement (FBRM) technique. The PBM follows the dynamics of aggregation and breakage processes underlying flocculation and provides a good approximation to the temporal evolution of aggregate size. The structure of the aggregates during flocculation is described by a constant or time-dependent fractal dimension. The results revealed that the compensations between the aggregation and breakage rates lead to a correct representation of the flocculation kinetics of the tailings of particles in seawater and, in addition, that the representation of the flocculation kinetics in optimal conditions is equally good with a constant or variable fractal dimension. The aggregation and breakage functions and their corresponding parameters are sensitive to the choice of the fractal dimension of the aggregates, whether constant or time dependent, however, under optimal conditions, a constant fractal dimension is sufficient. The model is robust and predictive with a few parameters and can be used to find the optimal flocculation conditions at different mixing intensities, and the optimal flocculation time can be used for a cost-effective evaluation of the quality of the flocculant used.

scholarly journals Improving the Flocculation Performance of Clay-Based Tailings in Seawater: A Population Balance Modelling Approach

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 782
Author(s):  
Gonzalo R. Quezada ◽  
Matías Jeldres ◽  
Pedro Robles ◽  
Norman Toro ◽  
David Torres ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Goodness Of Fit ◽  
Aggregate Size ◽  
Population Balance ◽  
Magnesium Content ◽  
Balance Model ◽  
Collision Efficiency ◽  
Reflectance Measurement ◽  
Vacuum Filtration ◽  
The Impact

A population balance model described the flocculation of clay-based mining tailings in treated seawater with reduced magnesium content. For the treatment, 0.06 M of lime was added to the liquor, generating solid magnesium complexes that were subsequently removed by vacuum filtration. Magnesium content varied between 10–1440 ppm when mixing raw seawater with treated seawater. The aggregate size was analysed by the Focused Beam Reflectance Measurement (FBRM) technology. The model follows the dynamics of the aggregation-rupture and it provides a good approximation to the temporal evolution. A decrease in collision efficiency was implemented as an indicator of the polymer depletion, describing the size reduction. Lower magnesium content makes larger aggregates with a higher fractal dimension, but an increase in the concentration of clays reduces both the size of aggregates and the fractal dimension, indicating more open and porous structures, with higher permeability to the passage of fluid. The model efficiently illustrates the experimental data, with R-square (R2) greater than 0.9 and Goodness of Fit (GoF) greater than 95% in most cases, wherein the fitting parameters allowed for analysing the impact of magnesium and clays on the collision efficiency, collision frequency, and fragmentation rate. The model is predictive with few parameters, and it is potentially a powerful tool for water management optimisation.

scholarly journals QMOM-based population balance model involving a fractal dimension for the flocculation of latex particles

2016 ◽  
Vol 155 ◽  
pp. 65-82 ◽  
Author(s):  
Mélody Vlieghe ◽  
Carole Coufort-Saudejaud ◽  
Alain Liné ◽  
Christine Frances
Keyword(s):  
Fractal Dimension ◽  
Population Balance ◽  
Balance Model ◽  
Population Balance Model ◽  
Latex Particles

scholarly journals Dynamic simulation of industrial-scale gibbsite crystallization circuit

2021 ◽  
Vol 247 ◽  
pp. 88-101
Author(s):  
Vladimir Golubev ◽  
Tatyana Litvinova
Keyword(s):  
Aluminum Hydroxide ◽  
Population Balance ◽  
Industrial Scale ◽  
Balance Model ◽  
Population Balance Model ◽  
Precipitation Process ◽  
Oscillatory Process ◽  
Quality Of Control ◽  
Cyclic Changes

Population balance model is crucial for improving the method of aluminum hydroxide massive crystallization and enhancing the quality of control over industrial precipitation trains. This paper presents the updated population balance model, which can be used for simulation of industrial-scale precipitation. Processes of birth-and-spread and particle breakage are considered integral parts of the precipitation process along with secondary nucleation, growth and agglomeration of particles. The conceptual difference of the proposed system of equations is its ability to reproduce the oscillatory process that occurs in precipitation circuits as a result of cyclic changes in the quality of the seed surface. It is demonstrated that self-oscillations can occur in the system without any external influence. The updated model is adjusted and verified using historical industrial data. The simulation of seed-recycle precipitation circuit showed an exact correspondence between the calculated dynamic pattern of changes in particle size distribution of aluminum hydroxide and the actual data.

scholarly journals Reducing the Magnesium Content from Seawater to Improve Tailing Flocculation: Description by Population Balance Models

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 329
Author(s):  
Gonzalo R. Quezada ◽  
Matías Jeldres ◽  
Norman Toro ◽  
Pedro Robles ◽  
Ricardo I. Jeldres
Keyword(s):  
Fractal Dimension ◽  
Population Balance ◽  
Magnesium Content ◽  
Reflectance Measurement ◽  
Vacuum Filtration ◽  
Irregular Structure ◽  
Mean Size ◽  
The Mean ◽  
Magnesium Removal ◽  
Suitable Environment

Experimental assays and mathematical models, through population balance models (PBM), were used to characterize the particle aggregation of mining tailings flocculated in seawater. Three systems were considered for preparation of the slurries: i) Seawater at natural pH (pH 7.4), ii) seawater at pH 11, and iii) treated seawater at pH 11. The treated seawater had a reduced magnesium content in order to avoid the formation of solid complexes, which damage the concentration operations. For this, the pH of seawater was raised with lime before being used in the process—generating solid precipitates of magnesium that were removed by vacuum filtration. The mean size of the aggregates were represented by the mean chord length obtained with the Focused beam reflectance measurement (FBRM) technique, and their descriptions, obtained by the PBM, showed an aggregation and a breakage kernel had evolved. The fractal dimension and permeability were included in the model in order to improve the representation of the irregular structure of the aggregates. Then, five parameters were optimized: Three for the aggregation kernel and two for the breakage kernel. The results show that raising the pH from 8 to 11 was severely detrimental to the flocculation performance. Nevertheless, for pH 11, the aggregates slightly exceeded 100 µm, causing undesirable behaviour during the thickening operations. Interestingly, magnesium removal provided a suitable environment to perform the tailings flocculation at alkaline pH, making aggregates with sizes that exceeded 300 µm. Only the fractal dimension changed between pH 8 and treated seawater at pH 11—as reflected in the permeability outcomes. The PBM fitted well with the experimental data, and the parameters showed that the aggregation kernel was dominant at all-polymer dosages. The descriptive capacity of the model might have been utilized as a support in practical decisions regarding the best-operating requirements in the flocculation of copper tailings and water clarification.

scholarly journals Copper Tailing Flocculation in Seawater: Relating the Yield Stress with Fractal Aggregates at Varied Mixing Conditions

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1295 ◽  
Author(s):  
Matías Jeldres ◽  
Eder C. Piceros ◽  
Norman Toro ◽  
David Torres ◽  
Pedro Robles ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Rheological Properties ◽  
Yield Stress ◽  
Structural Changes ◽  
Structural Characteristics ◽  
Mixing Time ◽  
Aggregate Size ◽  
Mixing Rate ◽  
Reflectance Measurement ◽  
Mixing Intensity

The implications of physical conditions of the feedwell on the rheological properties of synthetic copper tailings, flocculated in seawater, were analysed. The mixing intensity of flocculation was related to the structural characteristics of the aggregates, and the outcomes were linked to the yield stress of the pulp sediments. Tailings settling assays were conducted by using a 30 mm turbine type stirrer with an in-situ aggregate size characterisation. The structural characteristics of the aggregates were determined by using the focused beam reflectance measurement (FBRM). After a mixing time between the pulp and the flocculant, the sample was allowed to settle for 2.5 h, where the variation of the sediment height was minimal. The sediment was gently removed and subjected to rheological characterisation. The yield stress was measured on an Anton Paar MCR 102 rheometer (ANAMIN Group, Santiago, Chile), with a vane-in-cup configuration. The mixing intensity was related to the characteristics of the aggregates, and the outcomes were linked to the yield stress of the flocculated pulp sediments. More aggressive hydrodynamics deteriorated the structure of the aggregates, promoting the reduction of both its size and the fractal dimension. This brought direct consequences on the rheological properties of the sediments: at higher mixing level, the yield stress was lower. The explanation lies in the structural changes of the aggregates, where at a fixed mixing rate, the yield stress presented a seemingly exponential increase over the fractal dimension. Additionally, correlations were found between the rheological properties with settling rate and aggregate size.

Influence of mineral elements on the yield and quality of grain of the prospective line in winter tritikale

2020 ◽  
Author(s):  
I.N. Voronchikhina ◽  
◽  
A.G. Marenkova ◽  
V. S. Rubets ◽  
V. V. Pylnev
Keyword(s):  
Cost Effective ◽  
Mineral Elements ◽  
Early Spring ◽  
High Potential ◽  
Winter Triticale ◽  
Yield And Quality ◽  
Fertilizer System

The results of elements development of varietal agrotechnics of a new high-potential line 238h of winter triticale presented. It was identified that under the conditions of 2020 the most cost effective fertilizer system is an early spring application of NPK (S) (15-15-15 (10)) at a dose of 200kg/ha. The profitability level of this fertilizer was 88,9%.

Regulatory Issues in Pakistan Telecommunication

1998 ◽  
Vol 37 (4II) ◽  
pp. 873-882 ◽  
Author(s):  
Sarfaraz Khan Quershi
Keyword(s):  
National Economy ◽  
Cost Effective ◽  
Market Forces ◽  
Global Trends ◽  
Regulatory Issues ◽  
Competitive Price ◽  
Modern Services ◽  
A Company ◽  
Telecom Infrastructure

Growth in telecom infrastructure and provision of modern telecom services to consumers at a cost based tariff helps growth of national economy. Modern telecoms serve as the engine of growth of national economy. Following the global trends of liberalisation and deregulation in telecoms monopolies which have thus far been providing inefficient communication at a greedily high tariffs are falling apart. Mergers in telecoms are not for increasing the size of the monopoly but to provide more efficient and cost effective services to the consumers. In Pakistan the erstwhile T&T department played a needful role at its time. Conversion of the department into a corporation and then into a company were steps necessary for following the global trends. Need now is to continue this trend further, eliminate the monopolistic approach by allowing more players in the field thus permitting the market forces to decide the provision of better quality of modern services at competitive price.

A Sample Preparation on Decapsulation Methodology for Effective Failure Analysis on Thin Small Leadless (TSLP) Flip Chip Package with Copper Pillar (CuP) Bump Interconnect Technology

2014 ◽  
Author(s):  
Gwee Hoon Yen ◽  
Ng Kiong Kay
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Flip Chip ◽  
Fault Localization ◽  
Cost Effective ◽  
Fault Isolation ◽  
Voltage Contrast ◽  
Interconnect Technology

Abstract Today, failure analysis involving flip chip [1] with copper pillar bump packaging technologies would be the major challenges faced by analysts. Most often, handling on the chips after destructive chemical decapsulation is extremely critical as there are several failure analysis steps to be continued such as chip level fault localization, chip micro probing for fault isolation, parallel lapping [2, 3, 4] and passive voltage contrast. Therefore, quality of sample preparation is critical. This paper discussed and demonstrated a quick, reliable and cost effective methodology to decapsulate the thin small leadless (TSLP) flip chip package with copper pillar (CuP) bump interconnect technology.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

Fracture-Tolerant and Shear-Resistant Interlayers for Mitigation of Reflective Cracking

2019 ◽  
Vol 2673 (10) ◽  
pp. 35-46
Author(s):  
Cristian Cocconcelli ◽  
Bongsuk Park ◽  
Jian Zou ◽  
George Lopp ◽  
Reynaldo Roque
Keyword(s):  
Asphalt Pavement ◽  
Aggregate Size ◽  
Cost Effective ◽  
Design Guidelines ◽  
Reflective Cracking ◽  
Rubber Membrane ◽  
Near Surface ◽  
Field Evidence ◽  
Cracking Performance ◽  
Interface Cracking

Reflective cracking is frequently reported as the most common distress affecting resurfaced pavements. An asphalt rubber membrane interlayer (ARMI) approach has been traditionally used in Florida to mitigate reflective cracking. However, recent field evidence has raised doubts about the effectiveness of the ARMI when placed near the surface, indicating questionable benefits to reflective cracking and increased instability rutting potential. The main purpose of this research was to develop guidelines for an effective alternative to the ARMI for mitigation of near-surface reflective cracking in overlays on asphalt pavement. Fourteen interlayer mixtures, covering three aggregate types widely used in Florida, and two nominal maximum aggregate sizes (NMAS) were designed according to key characteristics identified for mitigation of reflective cracking, that is, sufficient gradation coarseness and high asphalt content. The dominant aggregate size range—interstitial component (DASR-IC) model was used for the design of all mixture gradations. A composite specimen interface cracking (CSIC) test was employed to evaluate reflective cracking performance of interlayer systems. In addition, asphalt pavement analyzer (APA) tests were performed to determine whether the interlayer mixtures had sufficient rutting resistance. The results indicated that interlayer mixtures designed with lower compaction effort, reduced design air voids, and coarser gradation led to more cost-effective fracture-tolerant and shear-resistant (FTSR) interlayers. Therefore, preliminary design guidelines including minimum effective film thickness and maximum DASR porosity requirements were proposed for 9.5-mm NMAS (35 µm and 50%) and 4.75-mm NMAS FTSR mixtures (20 µm and 60%) to mitigate near-surface reflective cracking.

Sign in / Sign up

Export Citation Format

Share Document