Effect Of Solids Concentration Research Articles

An Invitation on Characterization of H2-Reduced Bauxite Residue and Recovering Iron through Wet Magnetic Separation Processes

Recovering iron from the bauxite residue (BR) is one of the long-standing challenges in the mining industry. However, there is a substantial lack of information in the literature regarding sample properties and iron extraction by reducing hydrogen. The present study aims at reducing a Greek BR using hydrogen, its characterization, and separating iron by magnetic separation processes. To this end, the reduced sample was characterized using X-ray diffractometry analysis (XRD), X-ray fluorescence spectrometer analysis (XRF), thermomagnetic analysis (TMA), automated mineralogy (AM), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The effect of particle size (−200 + 100 µm, −100 + 75 µm, and <75 µm) was investigated through a medium-intensity magnetic separation (MIMS, Davis Tube) at 1000–2500 Gauss and a Slon® magnetic separator (1000 G). The effects of solid content (3% and 10% w/w) in a wet low-intensity magnetic separation (WLIMS, 350 G) and a two-stage MIMS followed by WLIMS were investigated. It was revealed that through reduction at 500 °C and 2 h with 20 wt% NaOH under 5 vol.% H2 + 95 vol.% N2, iron oxides and ferric oxyhydroxide (Fe2O3 and FeOOH) were converted into magnetite (Fe3O4), whereas aluminum (oxy)hydroxides (Al(OOH), Al(OH)3) were reacted with Na+ towards sodium aluminates (NaAlO2). The AM observations indicated that only 3% of iron was in the phase of liberated magnetite, and the remaining was associated with Na, Al, and Ti phases with different intensities. The dissemination of iron throughout the matrix of the sample was recognized as the principal challenge in the physical separation processes. It was found that increasing magnetic intensity from 1000 G to 2500 G resulted in improved recovery for all studied particle size fractions in Davis Tube tests. The particle range of −106 + 74 µm was chosen as the most appropriate size to achieve the maximum Fe content of 41%. The results of WLIMS (350 G) showed the maximum Fe grade but revealed less recovery of 52% and 27% at 10% and 3% solid contents, respectively, compared to the Davis Tube trials.

Effect of High Solid Concentration on Friction in a Transitional and Turbulent Flow of Bioliquid Suspension

Some suspensions in nature have a complex structure and demonstrate a yield shear stress and a non-linear relationship between the shear rate and the shear stress. Kaolin clay suspension is such an example in engineering, whereas in nature it is blood. This study represents an innovative approach to simulate bioliquid flow, similar to that of blood when the solid concentration is high. The objective of this study is to examine the influence of high solid concentration of bioliquid, similar to blood, on energy losses and velocity profiles in turbulent and transitional flow in a narrow tube. Using the analogy between the suspension of kaolin clay and blood, the physical model and the mathematical model were formulated. The mathematical model comprises continuity and time-averaged momentum equations, a two-equation turbulence model for low Reynolds numbers, and a specially developed wall damping function, as such suspensions demonstrate the damping of turbulence. Experimental data on blood rheology for solid concentrations equal to 43% and 70% by volume, gathered from the literature, were used to establish a rheological model. The results of the simulations indicated that an increase of solid concentration in bioliquid suspension from 43% to 70% causes an increase in wall shear stress to approximately 10% and 6% for transitional and turbulent flow, respectively, and changes in velocity profiles. Such simulations are important if an inserted stent or a chemical additive to the bioliquid suspension is considered, as they can influence the shear stress. The results of the simulations are presented in graphs, discussed, and conclusions are formulated.

Preparation of hydrogels based on poplar cellulose and their removal efficiency of Cd(II) from aqueous solutions.

Industrial heavy metal-contaminated wastewater is one of the main water pollution problems. Adsorbents are a promising method for the removal of heavy metal contaminants. Herein, polyaspartic acid/carboxymethyl poplar sawdust hydrogels (PASP/CMPP) and ascorbic acid/carboxymethyl poplar sawdust hydrogels (VC/CMPP) were prepared by aqueous polymerization using alkalized poplar sawdust (CMPP) as the substrate and PASP and vitamin C (VC) as modifiers. The effective results, provided by the characterization analysis of SEM and BET, indicate that the surface of the PASP/CMPP hydrogel has a larger number of loose pores and a larger pore volume than the VC/CMPP hydrogel. The treatment effects of the two hydrogels on simulated wastewater containing Cd(II) were investigated by a batch of experiments. The results showed that PASP/CMPP had a better adsorption effect than VC/CMPP under the same adsorption conditions. Interestingly, the solid concentration effect was found in the process of sorption kinetics and sorption isotherms. The sorption kinetic curves of Cd(II) on PASP/CMPP were well-fitted by the quasi-second-order kinetics under different adsorbent concentrations. The adsorption conforms to Langmuir and Freundlich adsorption isotherm models. More importantly, PASP/CMPP composites are expected to be used as a new kind of environmental adsorbent for wastewater treatment.

Effects of Organic Additives on the Properties of Boronsilicate Glass/Al2O3 Composites Tape Casting Slurries and Green Tapes

Tape casting was a new type of low temperature co-fired ceramic (LTCC) forming process, the key to which was the formation of slurry. Suspensions consisting of boronsilicate glass/Al2O3 powders and organic solvent system were studied, in addition, the effect of solid content and mixing time on the property were also investigated. The results indicated that the optimized parameters of the slurry are 55 wt. % boronsilicate glass/Al2O3 composites powders, the three azeotropic solvents (Ethanol/ Dimethylbenzene/ Dimethylcarbinol=30 wt.%: 10 wt.%: 60 wt.%), 3.0 wt.% dispersant, the ratio of plasticizer to binder(R=0.65), and mixing time (20 hours). The green tape had smooth and homogeneous surfaces without cracks, and the sintered sample had a high relative density.

High consistency enzymatic pretreatment of eucalyptus and softwood kraft fibres for regenerated fibre products

Sustainability of regenerated cellulosic fibres could be improved by using paper grade pulp instead of dissolving pulp as a raw material in the fibre spinning process. However, the use of paper grade pulp calls for adjustment of the molar mass distribution (MMD) prior to dissolution to obtain good solubility and spinnability. The objective of this work was to adjust MMD of softwood and eucalyptus kraft pulps by enzymatic treatments at high pulp consistency. The reduction of the MMD of eucalyptus kraft pulp was found to require a nearly 30-fold higher dose of endoglucanase compared to the treatment of softwood pulp. Interestingly, when xylanase was used in combination with endoglucanase to treat eucalyptus kraft pulp, 27% of the xylan was dissolved and the required endoglucanase dose could be decreased from 0.57 to 0.06 mg/g. The endoglucanase dose could be further decreased to 0.028 mg/g when 67% of xylan was removed chemically before the enzymatic treatment. This suggests that xylan hinders endoglucanase action on eucalyptus kraft pulp. For softwood pulp, the addition of xylanase and mannanase had only a minor impact on the treatment efficiency. The different processabilities of softwood and eucalyptus kraft pulps are suggested to originate from the deviating cellulose accessibility which is affected by the fibre structures as well as their hemicellulose composition and localisation. The effect of the treatment consistency was further studied with softwood kraft pulp. Treatment at high consistency clearly enhanced the endoglucanase action whereas the effect of solid content on the hemicellulase action was modest.

Effect of Pressure, Concentration and Sludge Volume on Two-phase Filtrate Volumes Using Bentonite Clay Sludge

The effect of pressure, solids concentration and volume of slurry on total and two-phase filtrate volumes was investigated to establish optimum conditions for routine laboratory filtration. Full factorial design with three levels was utilized to obtain 27 unique experiments. The slurry used was prepared by mixing crushed and sieved bentonite clay of 75 microns with distilled water at different concentrations as obtained from the design of experiment. A filter press was utilized and the results were used to calibrate a two-phase exponential equation for sludge filtration to extract the first and second stage filtrate volumes. The total filtrate volume improved with increasing applied pressure and decreasing solids concentration. A slurry volume of 0.22 litres was found to be ideal. Similar effects were noticed on the first and second stage filtrate volume except that an optimum was discovered at 0.18 litres of slurry. The second stage filtration produced an upward curve with a point of inflection at a range of 0.18 to 0.22 litres of slurry. The second stage filtrate volume is also discovered to be directly proportional to the total filtrate volume. This connection may be considered for use to assess the filterability of other slurries.

Investigations into the closed-loop hydrometallurgical process for heavy metals removal and recovery from biosolids via mild acid pre-treatment

Biosolids contain heavy metals (HMs), restricting their beneficial reuse in agricultural land. However, these metals can be a valuable resource in many applications if recovered efficiently. Therefore, the removal and recovery of HMs and other limiting contaminants in biosolids without degrading the organic nutrients of the resulting treated biosolids demands holistic investigations. A closed-loop hydrometallurgical treatment process for metal removal and recovery from biosolids was developed in this study. Firstly, mild acid treatment using 3% v/v H2SO4 at 25 °C, 600 rpm for 30 min was performed in a 1 L continuous stirred tank reactor to extract common HMs (such as As, Cd, Co, Cr, Cu, Ni, Pb, and Zn) from biosolids into the aqueous phase. The effects of solids concentration and acid types on the HMs extraction efficiency were studied. Then, the primary acid leachate stream was continuously recycled for metal extraction from biosolids until the dissolved metals in the solution reached saturation concentration. After that, the dissolved metals were recovered in staged NaOH precipitation and adsorption. Low solids contents (<5% w/v) using mineral acids having pH <2 and oxidation-reduction potential (ORP) ∼500 mV (versus SHE) favoured HMs solubilisation from biosolids with an average extraction efficiency of 70%. The dissolution of ferric iron (Fe3+) by H2SO4 and subsequent in-situ formation of ferric sulfate enhanced the metal extraction strength of the spent leachate stream during recycling. However, the solids loading in each leaching process must be kept low to prevent ferric concentration build-up and precipitation as the leachate pH steadily increases above 2 during recycling. Amongst the metal recovery methods investigated, H2O2 oxidation prior to 2-stage NaOH precipitation had the highest efficiency with 75–95% HMs recovery. The clarified stream was used to neutralise the acidic treated biosolids to close the process loop. The complete process flowsheet was developed with mass balances, and the fate of nutrients (mainly C, N, and P) and major per- and polyfluoro alkyl substances (PFAS) were overviewed.

Nanoparticle Tracking Analysis: Enhanced Detection of Transparent Materials

AbstractThis study proposes a novel and simple in‐house design of a nanoparticle tracking analysis (NTA) device for the online characterization of nanoparticles in an aqueous solution. The particle size distribution of two sets of model nanoparticles, for example, transparent (SiO2) and opaque (TiO2) materials with respect to water as a dispersion medium could be successfully analyzed. Experiments are conducted using two different laser wavelengths of 632.8 (red) and 510 nm (green) and a range of concentrations. The accuracy of the green laser is larger compared to the red laser for all particle concentrations used. The measured average diameter using the presented in‐house NTA setup is in the acceptable range compared to the electron microscopy data. The average diameter of the transparent (SiO2) and opaque (TiO2) samples is calculated as 36.29 and 27.26 nm using NTA, 36.44 and 27.8 nm analyzing field emission scanning electron microscopy images, and 23.97 and 19.7 nm analyzing transmission electron microscopy images. In the new viewing sample holder, nanoparticles undergo mere Brownian motion with no bulk drift velocity. The effect of solid concentration and wavelength of the laser light on the performance of the NTA sensor is investigated, and the optimal concentration range for model particles is reported.

Hydrothermal treatment enhances energy recovery from pig manure digestate and improves the properties of residues

Energy recovery from biowaste is of high significance for a sustainable society. Herein, hydrothermal treatment (HT) was applied to valorize pig manure digestate. The effects of hydrothermal operational parameters, including temperature (130-250 °C), residence time (15-90 min), and total solid (TS) concentration (10%-20%), on reducing sugar yield were investigated in this study. Among them, hydrothermal temperature was identified as the most important factor influencing reducing sugar yield, followed by the TS concentration and time. The optimal hydrothermal conditions for the pig manure digestate were 175.6 °C, 35.4 min and a TS concentration of 10% with a reduced sugar yield of 9.81 mg gTS−1. The addition of hydrolysate could enhance methane production by 21.6-50.4% from the anaerobic digestion of pig manure than that without the hydrolysate addition. After HT, the hygienic quality, including fecal coliform number and ascaris egg mortality, was improved in the residual digestate. Antibiotics such as sulfamonomethoxine, oxytetracycline, doxycycline and sulfaclodazine in the pig manure digestate were decomposed during HT and decreased environmental risk. These findings indicated that the hydrothermal process might be an effective technique to recover energy from the digestate of livestock and poultry manure and to improve the residual digestate for subsequent utilization.

Effect of solid particle type, concentration and size on DC breakdown voltage of short needle‐plate air gap: An experiment and simulation study

AbstractUnclean air discharge refers to the discharge phenomenon of a large number of polluting gases, droplets or solid particles floating in the air, which will cause insulation breakdown and safety accidents for the power transmission equipment that have been left outdoors for a long time. In order to investigate the effects of particle concentration, particle size and dielectric constant on DC breakdown characteristics of unclean air gap, a self‐made discharge chamber was designed in this study. The air was filtered and passed into the discharge chamber to remove the influence of impurities contained in the air on the experimental results. Then, solid particles with different concentration, particle size and particle dielectric constant were added to the discharge chamber to carry out the DC positive polarity breakdown characteristic experiment. The experimental results show that compared with dry clean air, the presence of solid particle increases the breakdown voltage of the gap, and the increase proportion of breakdown voltage is related to the particle concentration, particle size and particle dielectric constant. With the same particle type and particle size, the increase proportion of breakdown voltage increases with the higher concentration, which up to 10.49%. For further investigating, the fluid mechanics model was selected to simulate the process of streamer discharge in unclean air. The results show that compared with dry clean air, the presence of particles enhances the gap discharge ionisation process, but also enhances the adsorption of particles, and the latter has stronger effect than the former, thus increases the gap breakdown voltage. At the same time, the enhancement of adsorption effect increases the electric field intensity of the gap and speeds up the development process of streamer discharge.

Effect of Solid Concentration and Particle Size on the Flotation Kinetics and Entrainment of Quartz and Hematite

Despite the importance of solid concentration in froth flotation, its effect on flotation kinetics and entrainment has rarely been studied. In this study, the flotation kinetics and entrainment in quartz and hematite single-mineral flotation systems as a function of the solid concentration and particle size were investigated using dodecylamine acetate as a collector. Kinetics modeling showed that the Gamma distribution achieved the best agreement with the experimental data, whereas the Classical and Klimpel models poorly fit the data (e.g., RMSE). The flotation rate constants (k) of both quartz and hematite at a higher solid concentration showed a concave shape, with the inflexion point at the middle-size range, whereas this trend altered at lower solid concentrations. Overall, quartz exhibited higher equilibrium recoveries (R∞) than hematite, which indicates its better overall rate constants. The degree of water recovery in both the quartz and hematite systems was higher at higher solid concentrations, but the hematite system exhibited higher water R∞ than the quartz system, meaning that the entrainment of gangue could be higher in direct hematite flotation than the reverse one. Therefore, a higher solid concentration is associated with better overall quartz recovery and can reduce hematite loss by entrainment during reverse flotation. An inverse relationship was identified between the solid concentration and particle size in terms of the ratio of water recovery to the concentrate. In the reverse flotation of iron ore, refraining from achieving equilibrium recovery could help limit entrainment, but this was not necessarily the case in direct flotation. No entrainment model or method other than the Warren and Ross model approximated the overall trends of flotation at the finest size range (−38 µm). However, extending the Warren method to polynomial distribution led to an improved fit with the experimental results. In addition to the solid concentration, particle density and size were revealed to be key to developing new entrainment models. Finally, after the fast recovery period (true flotation) was over, the slow recoveries were mainly driven by the slow-floating water fraction.

Preparation of spherical WC-Co powder by spray granulation combined with radio frequency induction plasma spheroidization

In this paper, spray granulation and radio frequency plasma spheroidization were used to obtain spherical WC-Co powder for laser powder bed fusion from mixed WC and Co powder. The effects of solid content and polyvinyl alcohol content of the slurry on granulated powder were studied. Then the spheroidization effects of different granulated WC-Co powders were investigated and compared. Results show that the granulated powder obtained from the slurry with solid content of 65 wt% and polyvinyl alcohol content of 2.5 wt% has the best performance after plasma spheroidization, whose flowability and apparent density are 10.20 s/50g and 6.76 g/cm3, respectively. Moreover, W and C distribute uniformly in the spheroidized WC-Co powder while the Co element is mainly distributed in the gaps of tungsten carbide. It is also noted that W2C, free carbon and Co3W3C appear in the spheroidized WC-Co powders due to the decomposition of WC during the plasma spheroidization process. Furthermore, the decomposition of WC-Co powder particles with smaller size is more serious, which leads to the presence of black and white particles with significantly different carbon content distribution in the spheroidized powder.

Improving flotation separation of micro Si/SiC particles from silicon sawing waste by surface hydrophilic modification

Silicon sawing waste (MSW) produced by mortar cutting causes serious environmental issues and a waste of high-purity silicon. The major obstacle in the recovery of high-purity silicon (Si) is the separation of microscale Si and silicon carbide (SiC) in MSW. In this study, micro Si/SiC in silicon sawing waste was separated effectively by bulk-oil flotation after surface hydrophilic modification of Si particles. The structural evolution of micro Si surface after wet oxidization in water and acid was characterized by FT-IR, TEM, and XPS. Specifically, the wet oxidization process reduced the contact angle from 63 ± 0.3° to 18.5° of Si surface for the coating of an amorphous oxide with hydroxy groups on Si particles enhanced the wettability. The amorphous oxide layer with hydroxy coated on Si particles played a key role in enhancing the wettability of Si particles. The wet oxidization is essential to the subsequent flotation separation for the contact angle of SiC keeping at around 60.3°. The wettability of silicon sawing waste was further examined by the absorption of diesel. The effects of pH value and solid concentration on separation efficiency were studied. The best result obtained was 95% in Si recovery and 97.1 wt% in Si purity.

Mechanical Properties and Microstructure of Iron Tailings Cemented Paste Backfills Using Carbide Slag-Activated Ground Granulated Blast-Furnace Slag as Alternative Binder

For rational disposal of solid wastes, low-cost cemented paste backfills (CPB) were prepared with iron tailings, ground granulated blast-furnace slag (GGBS), and calcium carbide slag (CS). To ensure that CPB can be effectively utilized in mine backfill projects, the effects of solid contents, GGBS content, CS/GGBS ratio, and mixing water on the workability and mechanical properties of CPB were investigated. The results indicated that when the solid content was 70%, the GGBS content was 14%, the CS/GGBS ratio was 0.4, the mixing water was tap water, the fluidity of fresh CPB slurry was 167 mm, and 28d unconfined compressive strength (UCS) of CPB reached 2.89 MPa, at which time the effect of the activation of the GGBS with CS was optimal. The analysis of X-ray diffraction (XRD), scanning electron microscopic imaging (SEM), thermogravimetric analysis (TG-DTG), and Fourier transform infrared spectroscopy (FTIR) demonstrated that the hydration products are mainly C-S-H gels, C-A-S-H, hemicarbonate, and hydrotalcite in CS-GGBS cementitious material. The C-S-H gel content gradually increased with increasing curing time and CS content (15%–35%). When the CS content was increased to 25%, the C-S-H gel content significantly increased, which improved the overall structural compactness and increased the UCS of CPB.

Novel method of measuring solids settling velocity in concentrated slurry under sheared conditions using electrical resistance tomography (ERT)

Studying solids settling under sheared conditions is important for designing and operating slurry transportation pipelines. Electrical resistance tomography (ERT) is used for the first time to determine solids settling velocity under sheared conditions in a rheometer. The settling velocity of glass particles descending in 90 vol% glycerol solution located in the annular space between the ERT rheometer cup and bob was evaluated from conductivity data tracking particles' downward movement. The shear rate was varied from 5 to 125 s−1 by changing the bob rotational speed. Solids concentration ranged from 5 to 25 vol%. Settling velocity decreased with increasing solids concentration, slurry viscosity and shear rate. An empirical settling velocity correlation was developed using a modified Richardson-Zaki model incorporating the effects of solids concentration, slurry viscosity and shear rate. This correlation could be adopted as the basis for determining solids settling velocity for slurry transport in laminar flow in a pipeline.

Influence of rheology in the filtration of leach slurry generated by alkaline pressure leaching of a limestone ore

The Nuclear Power Plant, which uses uranium as a fuel, is considered as a clean source of energy with low carbon footprint and less environmental damage. In processing the uranium ore, the filtration of alkaline leach slurry generated by oxidative pressure leaching is a challenge due to very fine grind size coupled with high total dissolved solutes (TDS). The present study aimed at improving and understanding the filtration of the leach slurry with the help of slurry rheology. The effect of solid concentration, temperature, particle size, and dosages of dewatering aids on the rheological behavior of the slurry and the filtration performance was investigated. The slurry rheology was delineated by the Herschel–Bulkley model, temperature effects were incorporated using the Arrhenius type model, and particle size distribution (PSD) was represented by the Rosin–Rammler PSD model. The dosages of dewatering aids were compared using rheological parameters. It was found that the filtration rate decreases as solid concentration increases (10 to 75%, w/w) due to an increase in the shear stress (9.93 to 757 Pa at 1400 s−1). The leach slurry showed shear thickening at ≤ 60% solids (w/w) and shear thinning at ≥ 70% solids. The maximum solid packing volume fraction was found to be 0.59 and 0.54 at 1300 and 441 s−1, respectively. Increase in filtration rate was observed at elevated temperatures as the apparent viscosity (at 1300 s−1) decreased from 0.0195 Pa.s at 20 °C to 0.0135 Pa.s at 70 °C. The fluid flow activation energy was determined to be 5.5 and 7.1 kJ/mol at 1110 s−1 for 50 and 73% solid concentration (w/w), respectively. When the particle size (d90) was changed from 66 to 42 µm, a decrease in filtration rate was observed due to an increase in apparent viscosity from 0.0120 to 0.0163 Pa.s at 1400 s−1. The high molecular weight polyacrylamide based non-ionic synthetic flocculant N 100 and non-ionic biodegradable polysaccharide surfactant guar gum formed flocs through the bridging mechanism and gave best flocculation results, and therefore selected. The present work helps the researchers in better understanding and improving the filtration process of ore slurries.

Fibrous porous mullite ceramics modified by mullite whiskers for thermal insulation and sound absorption

In order to meet the demand for thermal insulation and sound absorption, fibrous porous mullite ceramics (FPMC) with high porosity and an interconnected pore structure were prepared, followed by a pore structure modification with in situ grown mullite whiskers on the three-dimensional framework of the FPMC. The resultant hierarchical material exhibited superior sound absorption performance in the low-to-medium frequency to most reported sound-absorbing materials, as well as a sufficient compressive strength of 1.26 MPa with low thermal conductivity of 0.117 W·m−1·K−1. Moreover, the effects of solid content and mullite whiskers on the microstructure and physical properties of the material were analyzed. The increase of solid content led to increased compressive strength and thermal conductivity and decreased frequency corresponding to the first sound absorption peak. The thermal conductivity and compressive strength of the material increased as the mullite whiskers grew, while the median pore size decreased.

Effects of solid particles on bubble breakup and coalescence in slurry bubble columns

Bubble size distribution (BSD) is a crucial parameter in the design and scale-up of slurry bubble columns (SBCs) as it affects the hydrodynamics, heat and mass transfers, and, consequently, the column overall performance. It is necessary to understand the impacts of various parameters on the bubble size to adequately predict the BSD. The population balance model is widely adopted to estimate the BSD by considering the bubble coalescence and breakup rates. Many bubble coalescence and breakup models have been proposed in literature to predict the BSD. However, the available models have been developed for two-phase (gas–liquid) systems. They are, hence, less appropriate for three phase (gas–liquid-solids) systems, as the presence of particles in these systems has considerable impacts on their hydrodynamics. Novel bubble breakup and coalescence models are developed in the present study to predict the effects of solids concentration and particle size on the bubble breakup and coalescence rates. The results showed that the presence of solids can increase both bubble coalescence and breakup rates, while the effect is more pronounced on the coalescence rate. In addition, an increase in the particle size increases the bubble breakup rate and decreases the bubble coalescence rate. An integrated population balance and hydrodynamic model was also developed to estimate the BSD and gas holdup in a slurry bubble column. The developed models in this study were successfully validated by experimental hydrodynamic data from literature and those obtained in our pilot-scale slurry bubble column. A set of parametric studies were accomplished to investigate the effects of solid particles on the bubble breakup, bubble coalescence, and BSD in two common industrial applications of SBCs.

The Effect of Solid Content Percentage and Concentration of Dispersing Agent (Anionic-Nonionic) on Quality of Polyester Dyed Fabric with Disperse by High Temperature/Pressure Method

This study aims to determine the % solid content to the determination of the concentration of the dispersing agent / leveler. Therefore, in order to determine the correct concentration, the % solid content varied, namely 43.930%, 21.975%, and 14.650%, with each concentration of dispersing/averaging agent 0 g/l, 0.5 g/l, 0.75 g /l, and 1.5 g/l. Furthermore, preliminary testing of solid content and dispersing power was carried out before the immersion application. The results of the most optimal dispersing power test were obtained at a variation of the concentration of the dispersing agent/average 1.5 g/l with a solid content of 43.93%. The results of the dyeing process were evaluated related to testing for color evenness, color aging, color fastness to washing, and rubbing. Based on the results of tests and evaluations, it shows that the variation of %solid content and concentration of dispersing agent/leveler has no effect on the value of color fastness to washing and rubbing. However, solid content and concentration of dispersing agent/leveler have an effect on color evenness, and color darkening. In this experiment, it can be seen that the most optimal color darkening is 28.1380, while the most optimal standard deviation of 0.187 is found in the concentration of dispersing agent/average of 1.5 g/l with a solid content value of 43.93%. The value of color fastness to wet and dry rubbing is 4-5.&#x0D;

Numerical modeling and analysis of particle-fluid flow and wall erosion in centrifugal slurry pumps under different solid concentrations

Wall erosion is a critical problem encountered in operation and maintenance of centrifugal slurry pumps. This paper presents a numerical study of the particle-fluid flow and wall erosion of industrial pumps. This is done by the dense discrete phase model. The model is validated by comparing the simulated results with the experimental measurements of pump hydraulic performance and jet erosion. Then, the effects of feed solid concentration are quantified under fixed motor power. The numerical results show that with increasing solid concentration, the pump efficiency increases first to a maximum and then decreases. The volute casing suffers the most erosion, which is generally not much sensitive to solid concentration. This is not the case for pre swirl vane and frame plate, whose erosion rate increases rapidly at relatively high solid concentrations. The results suggest that the model can be used as a cost-effective tool for pump design and control. • The dense discrete phase model is applied to study centrifugal slurry pumps. • It focuses on the effects of solid concentration on flow and wall erosion. • Volute casing suffers most erosion but is much insensitive to solid concentration. • The erosion of pre swirl vane and frame plate is sensitive to solid concentration.