Iron Ore Suspensions Research Articles

Role of nonionic natural dispersing agent Acacia Concinna on the slurryability and stability of concentrated iron ore suspension

The present study examines the impacts of saponin, extracted from the fruits of Acacia Concinna, in its effectiveness as a dispersant and stabilizer during the pipeline conveyance of iron ore particles. The basic fundamental characteristics of iron ore, which comprises a majority of hematite and has a size of (≤75 µm), have been examined and characterized. Iron ore water slurry (IWS) rheological behavior has been investigated as a function of saponin doses, pH, particle concentration, and the shear rate-shear stress correlation. The change in zeta potential with pH is used to compute the isoelectric point of IWS. An appropriate mechanism has been presented to explicate the interaction between saponin and particles of Iron ore. The surface-modified particles exhibit improved dispersion characteristics in the aqueous solution due to the modification of electrostatic force that the surface charge on each particle causes. Investigation indicates that the optimal proportion of saponin had a significant favorable effect on the fluidity and stability of the suspension. The analysis of the economic impact of the dispersant has been conducted through the evaluation of slurry head loss and specific energy consumption (SEC) pertaining to the implementation of the IWS pipeline in its intended commercial application.

Improving Rheology, Slurryability and Stability of Iron Ore Suspension Employing Variances in Size Distribution

Improving Rheology, Slurryability and Stability of Iron Ore Suspension Employing Variances in Size Distribution

Characterization and stabilization of iron ore suspension and influence of the mixture of natural additive Sapindus mukorossi and SDS on the slurryability

The traditional way of transporting iron ore from mine to end-use plants often causes the industry significant economic hardship and degradation of the ecological system. Hydrotransportation of slurry through a pipeline is a remarkably viable strategy for effectively transporting iron ore in terms of economics, dependability, and safety, with minimal environmental impact. In the present investigation, a blend of bimodal samples is prepared by mixing medium and coarse particles of Indian iron ore of size 38–75 (I-2) and 75–106 (I-3) µm, respectively, with finer particles of size <38 µm (I-1) in 10–40% (by weight) proportion. Rheological characterization of the blend samples is done to finalize the optimum particle size. To enhance the flowability and stability of the concentrated iron ore samples, they are amalgamated with a mixture of plant-based nonionic saponin extracted from Sapindus mukorossi (Ritha) and the anionic sodium dodecyl sulfate (SDS) surfactants. The correct proportion of SDS in saponin is obtained through a thorough analysis of critical micellar concentration, zeta potential, and rheological parameters. Finally, the stability and slurryability of iron ore suspension with a Saponin–SDS mixture are established through rheological properties, dispersant concentration, and stabilization mechanisms. It is found that the optimum proportion of a mixture of saponin–SDS significantly improved the slurryability and stability of iron ore suspension and the maximum iron ore loading was enhanced by up to 81% by weight. The head loss and specific energy consumption analysis successfully evidence the significance of the surfactants in transporting the slurry through pipelines.

Microwave assisted synthesis of guar gum based biopolymeric macromolecule optimized as a flocculant for mineral ore processing

The research endeavour to synthesize a novel, non-toxic, eco-friendly guar gum based biopolymeric macromolecule, [2-(methacryloyloxy) ethyl] trimethyl ammonium chloride grafted guar gum (GG-g-P (MAETMAC)) that has been optimized as a flocculant for mineral ore processing. The synthesis was performed using non-radiation and microwave assisted technique to compare and ensure the superiority of the latter. The intended grafting of monomer[2-(methacryloyloxy) ethyl] trimethyl ammonium chloride on to the biological macromolecule (guar gum) was confirmed through standard physico-chemical characterization techniques namely X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV–visible) spectroscopy, intrinsic viscosity study, etc. The flocculation efficacy of the synthesized novel graft copolymer was thoroughly investigated in kaolin, coal fine, and iron ore suspensions. We have explored a graft copolymer, [2-(methacryloyloxy) ethyl] trimethyl ammonium chloride grafted guar gum that has not been studied yet to the best of our knowledge. To establish the superiority of the synthesized biomaterial, the flocculation study revealed that the best grade of the synthesized novel graft copolymer showed flocculation efficacy of 90 % in kaolin, 69 % in Iron ore, and 29 % in coal fine suspensions which was significantly higher than using alum as a coagulant which provided 36 % efficacy in kaolin, 29 % in iron ore and 10 % in coal fine suspensions.

A hydrodynamic model of U-type reduction chamber for iron ore suspension roaster

U-type reduction chamber plays a significant role in the suspension roaster which has been proven to be one of the most highly efficient and clean magnetization equipment to utilize complex refractory iron ores. In the present work, a hydrodynamic model has been developed for the operation that the materials in the fluidization chamber are fluidized while the particles in the supply chamber are in a moving packed bed. Through fluid dynamic analysis, a hydrodynamic model including four equations has been established, whose solution results in the solids concentration in the fluidization chamber and materials' height in the supply chamber. Meanwhile, the effects of operating conditions such as fluidizing gas velocity and delivery rate on solids concentration in the fluidization chamber and materials' height in the supply chamber were studied by a combination of model analysis and experiments. The experiments were carried out in a U-type reduction chamber cold test apparatus with alumina particles. The model predictions showed good agreement with the experimental data, giving average errors below 6.28% and 4.96% respectively.

Studies on the fluidization performance of a novel fluidized bed reactor for iron ore suspension roasting

A U-type reduction chamber (URC) is developed as the key component of the novel iron ore suspension roaster. It consists of a fluidization chamber (FC) and a supply chamber (SC), and functions dually as sealing valve and reduction chamber. This roaster has been applied successfully to iron ore reduction roasting, while only limited information is available on its working mechanism. The fluid dynamic behavior of solid particles within URC and effects of operating parameters, i.e., the fluidizing air velocity, aeration air velocity and delivery rate, on its performance were investigated in this study. Simulation experiments on the fluid behavior of feed ores were conducted in a cold operating URC apparatus using alumina particles with an average size of 147 μm. It was found that the feeding particles descend in moving-bed mode in the supply chamber, while the particles move upwards in fluidization mode in the FC under suitable operating conditions. The differential pressure fluctuation reaches the maximum at the middle region of the FC, indicating vigorous gas-solid interactions at this area. The solids holdup presents an “S” shape distribution along the height of the FC. The average solids holdup and axial nonuniformity index range from 0.35 to 0.50 and from 0.10 to 0.40, respectively, which are relatively higher than those found in conventional fluidized bed reactors, ensuring better gas-solids contacting and mixing and promotion of reduction performance. In addition, the solids height in the SC could self-adjust to maintain pressure balance in the URC system under various operating conditions, and the pressure difference produced by solids at a certain height in the SC is the main driving force to keep normal flow of solid particles. The information obtained from this study could be helpful, especially for the regulation and control of industrial iron ore suspension roasting.

Synthesis, characterization and applications of polyacrylamide grafted fenugreek gum (FG-g-PAM) as flocculant: Microwave vs thermal synthesis approach

Fenugreek gum is modified using two different techniques: microwave-assisted and thermal synthesis technique of graft copolymerization. The synthesis was done by varying the concentration of acrylamide monomer and CAN initiator to get the best-grafted product. The physicochemical characteristics were determined by elemental analysis, FTIR spectroscopy, SEM, XRD, DSC, TGA, number-average molecular weight and intrinsic viscosity. All the grafted materials were tested by flocculation of different synthetic suspension media as well as river water. The process of deflocculation and refloccculation was also carried out and it was observed that refloccculation process has a good potential as the flocculation efficacy increased to a considerable extent. The flocculation efficacy increased from 92.05% to 94.32% upto a maximum of 95.98% in refloccculation process. The flocculation efficacy was found out to be 95.98%, 40.52% and 68.94% respectively kaolin, coal fine and iron ore suspensions. Flocculation was done in kaolin suspension of pH 2, 4, 7 and 10 and at different temperature range of 100, 250, 400 and 550C. It is expected that this material can be used as a highly efficient flocculant in future.

Rheological Characteristics of Uni/Bi-Variant Particulate Iron Ore Slurry: Artificial Neural Network Approach

A rigorous literature review has been carried out on rheological behavior of hard and soft particle slurries. The rheological characteristics of unimodal and bimodal suspension are presented. From experimentation, it was observed that mineral viscosity increases with solid concentration, while decreases with temperature. Addition of 30% (by weight) proportion of finer particles in coarse particles resulted in significant decrease in apparent viscosity of iron ore suspension. Artificial neural network approach was used for predicting the apparent viscosity of slurry.

A pressure drop model of U-typed reduction chamber for iron ore suspension roasting

A pressure drop model for a U-typed reduction chamber was proposed from the pressure balance law to predict pressure in the bottom of fluidization chamber under its stable operation state. During steady roasting, the feeding particles descend in moving-bed mode in the supply chamber, while the particles move upwards in fluidization mode in the fluidization chamber. A cold test system was established and operated to study the performance of the U-typed reduction chamber using alumina particles with average diameters of 70.77 μm, 101.09 μm and 146.66 μm, respectively. Experiments revealed that the pressure in the bottom part of fluidization chamber decreased with the increased fluidizing air velocity, while increased with the increase of delivery rate. Besides, the particles height of supply chamber would be automatically adjusted according to the system pressure balance. The simulated pressure drop was in good agreement with experimental data giving an average deviation of 7.30%, demonstrating the validity of proposed algebraic model. Therefore, it can be used to predict the pressure in the bottom of fluidization chamber for the U-typed reduction chamber.

Characterization of Iron-ore suspension at In-situ conditions

In present work, an attempt has been made to study the experimental characterization of Iron-ore suspension. Characterization of iron-ore suspension depends on physicochemical, morphological and flow characteristics. In this context, physical, chemical and flow properties of iron ore slurry had been investigated at solid concentration ranging from 20-50% (by weight). Rheological experiments were performed at shear rate ranging from 0-600 s-1. From experiments, it is observed that iron-ore slurry shows the Newtonian flow characteristics up to 30% solid concentration (by weight). Results showed that apparent viscosity of slurry increases with solid concentration. The modelling results obtained from Rosin-Rammler (RR) model found to be in good agreement with experimental data of mass distribution function F(d) as compared to Gates-Gaudin-Schumann (GGS).

Evaluation of the Flocculation Characteristics of Polyacrylamide Grafted Xanthan Gum/Silica Hybrid Nanocomposite

This manuscript illustrates the feasibility of polyacrylamide grafted xanthan gum/silica based nanocomposite toward its potential application as high performance flocculant for treatment of synthetic effluents and mine wastewater. The flocculation performance of the nanocomposite was systematically evaluated by floc size measurement as well as by traditional turbidity and settling velocity measurement. The flocculation kinetics is in good agreement with the aggregation of particle and particle collision model simultaneously. Furthermore, the effect of flocculant dosage on the synthetic effluent (kaolin and iron-ore suspensions) suggests that the bridging flocculation mechanism is predominating here. The graft copolymer-based nanocomposite also possesses a comprehensive color removal ability from mine wastewater.

Flocculation characteristics of polyacrylamide grafted hydroxypropyl methyl cellulose: An efficient biodegradable flocculant

Herein, the development and application of a high performance polymeric flocculant based on hydroxypropyl methyl cellulose grafted with polyacrylamide (HPMC-g-PAM) is reported. The flocculation characteristics were evaluated in two different synthetic effluents, namely kaolin and iron-ore suspensions using floc size measurement as well as traditional turbidity and settling velocity measurement. The flocculation kinetics demonstrate that it is in good agreement with both aggregation of particle and particle collision models. Moreover, raw mine wastewater was used for further investigation of the flocculation properties of HPMC-g-PAM. Above all, the flocculation experiments suggest that the HPMC-g-PAM based flocculants show better flocculation efficacy in compared to the base polysaccharide.

Ceric ion initiated synthesis of polyacrylamide grafted oatmeal: Its application as flocculant for wastewater treatment

Polyacrylamide grafted oatmeal (OAT-g-PAM) was synthesized by conventional method. The grafting of the PAM chains on the biomaterial backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H, N, S and O), SEM morphology and TGA study. The intrinsic viscosity of oatmeal appreciably improved on grafting of PAM chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied in coal fine suspension, kaolin suspension, iron-ore suspension and then in municipal wastewater through ‘jar test’ procedure.

Amphoteric amylopectin: A novel polymeric flocculant

Novel flocculant based on amphoteric amylopectin for wastewater and industrial effluents treatment has been developed in authors’ laboratory. Amphoteric flocculants have anionic and cationic moieties on the same macromolecule and is used to remove both positively and negatively charged contaminant particles in suspensions.Amylopectin based flocculants have been found to be highly efficient flocculant and hence it has been chosen as base polysaccharide. By grafting of polyacrylamide and subsequent hydrolysis, anionic amylopectin has been synthesized. Afterwards, a cationic moiety has been inserted both by chemical/microwave processing. The flocculation efficiency of the amphoteric amylopectin has been tested in kaolin and iron ore suspensions. The results indicate its high efficiency in comparison with anionic, grafted, and base amylopectin. The amphoteric amylopectin prepared via microwave irradiation showed best flocculation efficiency.

Grafted polysaccharides based on acrylamide and N,N‐dimethylacrylamide: Preparation and investigation of their flocculation performances

AbstractThe graft copolymerization of N,N‐dimethylacrylamide (DMA) and acrylamide (AM) were carried out onto different polysaccharide backbones separately. The graft copolymers were synthesized by ceric ion induced redox polymerization technique. Three polysaccharides were used, namely hydroxyethyl starch (HES), hydroxyethyl cellulose (HEC) and Amylopectin (AP), for the grafting reactions. Among the three polysaccharides, HEC has linear structure, while HES and AP have a branch one. The graft copolymers were characterized by intrinsic viscosity measurements, FTIR spectroscopy, NMR (both 1H and 13C) spectroscopy, and thermal analysis. Flocculation performances of the graft copolymers were evaluated in 1 wt % kaolin and in 0.25 wt % iron ore suspensions. A detailed comparative study of the flocculation properties of the synthetic graft copolymers was also made. It showed that graft copolymers based on DMA were better flocculants than those based on AM. Among the synthetic graft copolymers, HES‐g‐Poly (DMA) performed best when compared with the other synthetic graft copolymers as well as to the commercial flocculants in the same suspensions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis, characterization, flocculation, and rheological characteristics of hydrolyzed and unhydrolyzed polyacrylamide‐grafted poly(vinyl alcohol)

AbstractGraft copolymers of poly(vinyl alcohol) and polyacrylamide (PVA‐g‐PAM) were synthesized using a ceric ion–induced solution polymerization technique at 28°C. Three grades of graft copolymers were synthesized with varying acrylamide concentrations. Three grades of hydrolyzed products of PVA‐g‐PAM were synthesized with varying concentrations of sodium hydroxide solution. Hydrolyzed and unhydrolyzed PVA‐g‐PAM were characterized by viscometry, X‐ray diffractometry, infrared spectroscopy, and thermal analysis. Rheological investigation was also carried out on the aqueous solutions of various samples. The flocculation characteristics of various materials were investigated by the use of jar and settling tests in 0.25 and 5 wt %, respectively, using kaolin and iron ore suspensions. Among the series of graft copolymers, the one with fewest but longest PAM chains showed superior performance. The flocculation characteristics of the best‐performing graft copolymer were compared with those of various commercially available flocculants in the two suspensions under investigation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2109–2122, 2006

The flocculation and rheological characteristics of hydrolyzed and unhydrolyzed grafted sodium alginate in aqueous solutions

AbstractSodium alginate is a natural anionic polysaccharide obtained from natural and microbial resources. It is also used as a flocculating agent and thickener. It is grafted with polyacrylamide, in the presence of ceric ammonium nitrate (CAN) as an initiator. The graft copolymer (SAG‐g‐PAM) is again hydrolyzed with some amount of alkali. The flocculation characteristics of hydrolyzed graft copolymer (Hyd SAG‐g‐PAM) are compared with that of the unhydrolyzed ones, in 5 wt % kaolin and 10 wt % iron ore suspensions. The flocculation characteristics of the hydrolyzed graft copolymer are also compared with those of some of the commercial flocculants. The SAG‐g‐PAM and Hyd SAG‐g‐PAM are characterized by IR and intrinsic viscosity measurements. The rheological properties of aqueous solutions of hydrolyzed and unhydrolyzed graft copolymers are measured by Advanced AR‐1000 Rheometer. There is drastic enhancement in flocculation and viscosifying characteristics on hydrolysis of the graft copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1480–1488, 2004

High performance flocculating agent based on partially hydrolysed sodium alginate–g–polyacrylamide

The partial hydrolysis of the sodium alginate–g–polyacrylamide was carried out in alkaline medium. Four grades of partially hydrolysed products were synthesized by varying the reaction parameters. The neutralization equivalent of these products was determined by titrating with standard sodium hydroxide solution. Flocculation characteristics of all the hydrolysed graft copolymers and the unhydrolysed sodium alginate–g–polyacrylamide were determined in 10 wt% iron ore suspensions. The partially hydrolysed product with neutralization equivalent of 2865 gm shows better performance than other partially hydrolysed as well as unhydrolysed products in flocculation. The flocculation performance of the above best performing product was also compared with two commercially available flocculants Rishfloc-440 and Magnafloc-1011, as well as with one flocculant developed in our laboratory (amylopectin–g–polyacrylamide) in 10 wt% iron ore suspension. Here also it was found that the polymer with neutralization equivalent 2865 gm shows better performance than others.

Novel flocculating agent based on sodium alginate and acrylamide

Graft copolymers of sodium alginate with polyacrylamide were synthesized using a ceric ion initiated solution polymerization technique at 27±1°C. Six graft copolymers have been synthesized with a variation in the number and length of grafted polyacrylamide chains. The graft copolymers have been characterized by viscometry, IR spectroscopy, SEM and XRD study. Their flocculation characteristics were evaluated in 0.25 wt% kaolin and 10 wt% iron ore suspensions. The flocculation behaviour of one of the above grades has been studied on a 1 wt% coal suspension. The flocculation characteristics of these grafted polymers were also compared with various commercially available polymeric flocculants. Among the grafted alginates, it was observed that, the graft copolymers containing longer polyacrylamide chains were the most efficient.

The effect of iron ore suspensions and food on the shell growth rates and tissue weights of queen scallops Chlamys opercularis held in the laboratory

A machine to provide continuous supplies of Tazadit iron ore suspensions to queen scallops Chlamys opercularis held under controlled conditions of food supply, temperature and illumination, is described. The influence of iron ore suspensions, 0 to 70 mg litre -1, and micro-algae Tetraselmis suecica 0 to 1·3 × 10 4 cells per millilitre, on shell and tissue growth of C. opercularis has been studied. The main effect of iron ore was to reduce shell growth rates. Queen scallops exposed to iron ore suspensions (10·7 to 70 mg litre -1) from two experiments developed shell thickening on the interior surface of the shell valves. It is suggested that this condition, which is absent from queen scallops fed algal diets only, was caused by a general failure of the mantle edge to extend fully in the presence of iron ore particles in suspension. Unlike shell growth rates, there were no significant differences (p > 0·05) between the soft tissue weights of C. opercularis grown in concentrations of 0·4 to 70 mg Tazadit ore per litre and T. suecica and those grown only on T. suecica. Queen scallops provided with a diet of 6·67 × 10 3 Tetraselmis cells per millilitre produced average laboratory shell growth rates ranging from 19·0 to 110·0 μm day -1 depending on the size of the animal and time of year the experiment was carried out. These rates are comparable with rates found in suspended cages in the natural environment.