scholarly journals Chemometric Optimisation of a Copper Sulphide Tailings Flocculation Process in the Presence of Clays

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 582 ◽  
Author(s):  
Claudia Castillo ◽  
Christian F. Ihle ◽  
Ricardo I. Jeldres
Keyword(s):  
Settling Rate ◽  
Mixing Conditions ◽  
Fine Content ◽  
Operational Conditions ◽  
Coarse Aggregates ◽  
Series Of Experiments ◽  
Sulphide Tailings ◽  
Solids Content ◽  
Two Stages ◽  
Flocculation Process

The presence of fine and ultra-fine gangue minerals in flotation plants can contribute to sub-optimal valuable ore recovery and incomplete water recycling from thickeners, with the performance of the latter equipment relying on adequate flocculation. In order to study the dependence of the flocculation process on the suspension-flocculant mixing conditions, a series of experiments—chosen using chemometric analysis—were carried out by varying mixing conditions, solid concentration, water salinity and flocculant dosage. To this purpose, two different tailings (both featuring coarse and fine content) were considered and a response surface methodology based on a Doehlert experimental design was used. The results suggest that the operational conditions to optimise the flocculated tailings settling rate and the suspended solids that report to a thickener overflow are not necessarily the same. This is a reasonable outcome, given that the settling rate depends on the coarse aggregates generated in the slurry, while the overflow solids content is governed both by either fine particle content (and its characteristics) or small aggregates. It is inferred that to maximise dewatering performance two stages should be involved—a separate treatment of the thickener overflow to remove fine content and thickening at optimal flocculant dosage to enhance this process.

scholarly journals Qualidade de frutos de mangabeira de diferentes estágios de maturação tratados com CaCl2

2021 ◽  
Vol 10 (3) ◽  
pp. e21010313340
Author(s):  
Alexandre Passos Oliveira ◽  
Pryanka Thuyra Nascimento Fontes ◽  
Luiz Fernando Ganassali de Oliveira Junior
Keyword(s):  
Storage Period ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Ambient Atmosphere ◽  
Climacteric Fruit ◽  
Organoleptic Characteristics ◽  
The Difference ◽  
Solids Content ◽  
Hancornia Speciosa ◽  
Two Stages

Hancornia speciosa is a fruit tree, popularly known as mangabeiras. The mangaba, fruits of this tree, are quite appreciated for their organoleptic characteristics. Because it is a climacteric fruit, this fruit has very high perishability. The use of products that extend the useful life is necessary. Calcium chloride (CaCl2) has been shown to be an alternative in post-harvest because it promotes few changes in fruit quality and increases the storage period. Thus, the objective of this work was to evaluate quality attributes of mangaba fruits in two stages of maturation, 'Immature' and 'Mature', submitted to CaCl2 application, in four storage times (0, 2, 4 and 6 days) under ambient atmosphere. During the experiment, the loss of fresh weight, color, pH, titratable acidity, soluble solids and SS/TA ratio were evaluated. It was verified that the 'mature' fruits showed a higher acidity and soluble solids content, even with the application of CaCl2, the difference that the loss with the application of CaCl2 was smaller. Unlike '‘Immature’ and ‘Immature’ fruits with CaCl2 in which these characteristics were acquired as the experiment was conducted, in addition to presenting lower values for weight loss, pH and color.

scholarly journals Modification of Grout Properties in Prepacked Aggregate Concrete Incorporating Palm Oil Fuel Ash

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Reza Hodjati ◽  
Hossein Aslani ◽  
Iman Faridmehr ◽  
A. S. M. Abdul Awal ◽  
Ziba Kazemi
Keyword(s):  
Compressive Strength ◽  
Palm Oil ◽  
Palm Oil Fuel Ash ◽  
Aggregate Concrete ◽  
Coarse Aggregates ◽  
Fuel Ash ◽  
Pozzolanic Materials ◽  
Oil Fuel ◽  
Two Stages

Prepacked aggregate concrete (PAC) is a type of concrete that is placed in two stages where the coarse aggregates are first placed inside the formworks and then the grout is pumped from underneath through a manual pump. Grout properties including density, grout consistency, bleeding, and compressive strength are of great importance in PAC. Such properties could be improved by application of pozzolanic materials like palm oil fuel ash. This paper is aimed at finding the most optimum percentage of POFA replacement by weight of cement. It was concluded that 30% POFA replacement yielded the most optimum results.

scholarly journals Influences of Saturation and Wetting-Drying Cycle on Mechanical Performances of Argillaceous Limestones from Liupanshan Tunnel, China

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Bo Meng ◽  
Hongwen Jing ◽  
Wenxin Zhu ◽  
Haijian Su
Keyword(s):  
Peak Strain ◽  
Mechanical Parameters ◽  
Cycle Number ◽  
Rock Interaction ◽  
Small Pore ◽  
Strength And Deformation ◽  
Series Of Experiments ◽  
Reduction Effect ◽  
Mechanical Performances ◽  
Two Stages

Water-rock interaction is a vital factor to affect the stabilities of rock projects. This paper conducted a series of experiments on argillaceous limestones to investigate the influences of saturation and wetting-drying cycle on the physical and mechanical performances of rocks. The results show that the increasing saturation increases the dissolution of clay minerals and lubrication among mineral grains, resulting in an obvious reduction effect on the strength and deformation performances of argillaceous limestones. Wetting-drying cycle increases the porosity and changes the pore structure of argillaceous limestones, leading to the pore transformation from small pore (0.01∼0.1 μm) to relatively large pore (0.1∼1.0 μm). Both the physical and mechanical performances of argillaceous limestones are weakened by the wetting-drying cycle. Besides, the variation process of the physical and mechanical parameters, including mass loss, density, ultrasonic velocity, compression strength, peak strain, elasticity modulus, and secant modulus, can be divided into two stages: 0∼6th wetting-drying cycle, gently changing, and 6th∼12th wetting-drying cycle, drastically changing. The whole change process of these physical and mechanical parameters with the increase in the wetting-drying cycle number can be expressed with the exponential function in general.

scholarly journals New Natural Coagulant Aid in Water Treatment

2018 ◽  
Vol 203 ◽  
pp. 03004
Author(s):  
Jenny Siew Lee Chew ◽  
Agnes Yin Yee Ho ◽  
Boon Chin Lim ◽  
Wai Loon Chan ◽  
Yeek Chia Ho ◽  
...  
Keyword(s):  
The Other ◽  
Acid Extraction ◽  
Annona Muricata ◽  
Natural Coagulant ◽  
Operational Conditions ◽  
Microalgae Harvesting ◽  
Other Hand ◽  
New Material ◽  
Harvesting Efficiency ◽  
Flocculation Process

Natural source of coagulant is certainly being considered in addressing the disadvantages associated with the use of inorganic coagulants. Annona muricata is hypothesized to be new material as natural coagulant aid in coagulation-flocculation process. On the other hand, due to the high lipids content in microalgae, namely, Chlorella vulgaris is used in producing renewable energy, i.e. biodiesel. Coagulation-flocculation is an effective method in microalgae harvesting. Thus, in this study, a novel natural coagulant aid extracted from fruit waste in algae harvesting. It is aimed to (1) to extract natural coagulant aid (hereafter is known as biopolymer) extracted from Annona muricata seeds in algae harvesting, and (2) to evaluate the operational conditions of coagulation-flocculation process by utilizing the biopolymer. As a result, it is observed that acid extraction and extraction through sodium chloride does not show any yield. On the other hand, the harvesting efficiency showed positive response as coagulant aid at 20 mg/L.

scholarly journals Flocculation performance of anionic starch in oil sand tailings

2018 ◽  
Vol 78 (6) ◽  
pp. 1268-1275
Author(s):  
Nana Zhao ◽  
Hani Al Bitar ◽  
Yunyin Zhu ◽  
Yuming Xu ◽  
Zhiqing Shi
Keyword(s):  
Specific Resistance ◽  
Kaolin Clay ◽  
Settling Rate ◽  
Oil Sand ◽  
Natural Polymers ◽  
Capillary Suction ◽  
Fine Tailings ◽  
Solids Content ◽  
Clay Suspensions

Abstract A series of carboxymethyl starches (CMSs), with various degrees of substitution from 0.1 to 0.79, were synthesized and selected as a model to study the feasibility of using natural polymers as flocculants for oil sand tailings treatment. The flocculation performance of modified CMS in kaolin clay suspensions and oil sand tailings was evaluated in terms of settling rate, solids content, capillary suction time, and specific resistance to filtration of the sediment phase. It was found that the synthesized CMS effectively accelerates settling of kaolin suspensions and oil sand fine tailings, thus demonstrating the feasibility of this application.

scholarly journals ELECTROLYTIC PLASMA POLISHING OF COPPER

2018 ◽  
Keyword(s):  
Surface Modification ◽  
High Speed ◽  
Physical Processes ◽  
Modification Process ◽  
Complex Geometric Shape ◽  
Low Energy Consumption ◽  
Modification Method ◽  
Series Of Experiments ◽  
Plasma Electrolytic ◽  
Two Stages

Modern industrial technological processes require special preparation of metal surfaces. Currently, there are different methods of surface treatment of metal. Among them, it is possible to distinguish the method of electrolytic-plasma polishing (PEP– plasma electrolytic polishing) is distinguished as an innovative, due to its ecological properties, low energy consumption per unit of surface to be processed, high speed of modification and the possibility of processing parts of complex geometric shape. The main advantage of this method of surface modification is its ecological purity, which makes it possible to apply this technology to the food and pharmaceutical industry. Despite the large number of journal publications, electrolytic plasma polishing remains an innovative surface modification method that needs to be thoroughly studied in order to improve understanding of physical processes and optimize the surface modification process. The process of obtaining electrolytic plasma polishing of copper products in a solution of ammonium sulfate with the addition of sulfuric acid is considered in the paper. The experiment was divided into two stages. At first, the samples were treated for 600 seconds each for the obtain of temperature characteristics, with a strong correlation between the load current and the electrolyte temperature was observed. Dependence of the current on the temperature of the electrolyte showed four different modes of treatment. One of the modes showed the best results. During the second series of experiments, the processing of objects from 30 to 600 seconds. As a result of the conducted studies, optimal regimes for polishing copper objects were obtained.

scholarly journals Factors affecting soluble solids content of muskmelon (Cucumis melo L.).

1988 ◽  
Vol 36 (3) ◽  
pp. 239-246 ◽  
Author(s):  
G.W.H. Welles ◽  
K. Buitelaar
Keyword(s):  
Leaf Area ◽  
Fruit Growth ◽  
Soluble Solids ◽  
Soluble Solids Content ◽  
Maturation Period ◽  
Factors Affecting ◽  
Series Of Experiments ◽  
Solids Content ◽  
Cucumis Melo L ◽  
Fruit Load

The effects of fruit load, leaf area, night temperature, cultivar and ripening stage on the soluble solids content (SSC) of muskmelons were studied in a series of experiments performed during spring, summer and autumn in heated glasshouses. All factors except fruit load were found to affect SSC. In every experiment the duration of the maturation period (i.e. from fruit set to harvest) was positively correlated with SSC. In order to obtain fruits with a high SSC, it is important to achieve a low rate of fruit growth, i.e. a long maturation period. Low night temperatures in the period of fruit growth, a high leaf area, harvesting only ripe fruits and selecting slow-ripening cultivars may contribute to the production of fruits with high SSC. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals CO2 introduced the coagulation-flocculation of oil acidized wastewater: pollutant removal and cost analysis

2021 ◽  
Vol 83 (5) ◽  
pp. 1108-1117
Author(s):  
Jinyi Qin ◽  
Yifan Gong ◽  
Chuan Qin ◽  
Hailong Meng ◽  
Yiwen He ◽  
...  
Keyword(s):  
Cost Analysis ◽  
Contact Time ◽  
Settling Time ◽  
Pollutant Removal ◽  
Settling Rate ◽  
Residual Oil ◽  
Co2 Utilization ◽  
Flocculation Process

Abstract It is difficult to adjust the pH of oil acidized wastewater rich in Ca2+, thus hindering the polyacrylamide (PAM) flocculation. This study aims at accelerating the flocculation process by introducing CO2 into the water to induce the formation of CaCO3 nuclei. The order in which CO2 and NaOH were added affected the floc structures. Compared with CO2-NaOH-PAM, the flocs of NaOH-CO2-PAM were more compact and more CaCO3 crystals were formed. The aqueous Ca2+ involved in the reaction reached 20%, and CO2 utilization was enhanced. The settling time was shortened by half (from 20 to 3 min), and NaOH consumption was reduced by one-tenth (from 0.03 to 0.003 mol), hence significantly reducing the costs. Due to the higher settling rate and shorter contact time, the NaOH-CO2-PAM flocs adsorbed less so that the residual oil was 124 mg·L−1, while in the case of CO2-NaOH-PAM it was 88 mg·L−1. As a promising coagulation aid, CO2 can also be used to mineralize pollutants in wastewater.

Settling behaviour of pellet flocs in pelleting flocculation process: analysis through operational conditions

2010 ◽  
Vol 62 (6) ◽  
pp. 1346-1352 ◽  
Author(s):  
Zhang Gang ◽  
Huang Ting-lin ◽  
Tan Chi ◽  
Li Zhan-peng ◽  
He Wen-jie ◽  
...  
Keyword(s):  
Flow Rate ◽  
Settling Velocity ◽  
Process Analysis ◽  
Water Concentration ◽  
Operating Conditions ◽  
Raw Water ◽  
Pellet Size ◽  
Operational Conditions ◽  
Settling Behaviour ◽  
Flocculation Process

Pellet flocs' settling velocity is an important parameter in the pelleting flocculation blanket (PFB) process, hence, it is necessary to investigate flocs' settling behaviour to achieve the optimum operation parameters of the process. To investigate the settling behaviour of pellets under different operational conditions, a dynamic experiment was carried out to concentrate ferric flocs sludge by pelleting flocculation blanket (PFB) process with the scale of 0.5–1.2 m3/h. Under different operating conditions such as raw water concentration, polyacrylamide (PAM) dosage, up-flow rate, and agitation speed, pellet particles were sampled from different locations of the blanket in various operating stages to analyze pellet size, setting velocity, and porosity. Experimental results indicated that, when the PAM dosage increased from 0.59 mg/L to 1.18 mg/L, pellets size would flocculated from 2.25 mm to 3.52 mm with the settling velocity accelerated from 3.28 mm/s to 7.37 mm/s, while under the same up-flow rate, agitation intensity and PAM dosage, accompany with the raw water concentration increased from 216 mg/L to 840 mg/L, pellets settling velocity would improved from 6.03 mm/s to 13.6 mm/s. Under the experimental condition, along with the up-flow rate increased from 13.3 m/h to 40 m/h, pellets settling velocity would decreased from 4.39 mm/s to 3.42 mm/s due to its lower density.

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